CA2014355A1 - Information recording media - Google Patents
Information recording mediaInfo
- Publication number
- CA2014355A1 CA2014355A1 CA 2014355 CA2014355A CA2014355A1 CA 2014355 A1 CA2014355 A1 CA 2014355A1 CA 2014355 CA2014355 CA 2014355 CA 2014355 A CA2014355 A CA 2014355A CA 2014355 A1 CA2014355 A1 CA 2014355A1
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- Prior art keywords
- atom
- metallic layer
- hafnium
- aluminum alloy
- layer
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Abstract
ABSTRACT
In accordance with the present invention, there are provided information recording media having a substrate and thereon a recording layer, and a metallic layer composed of an aluminum alloy containing at least hafnium. The information recording media provided are excellent in corrosion resistance and also small in dependence of the recording power on linear velocity.
In accordance with the present invention, there are provided information recording media having a substrate and thereon a recording layer, and a metallic layer composed of an aluminum alloy containing at least hafnium. The information recording media provided are excellent in corrosion resistance and also small in dependence of the recording power on linear velocity.
Description
2~ 3 ,~
TIT~E
INFORMATION RECORDING MEDIA
FIELD OF THE INVENTION
S This invention relates to information recording media having a metallic layer and more particularly to information recording media excellent in corrosion resistance or stability, and small in dependence of their recording power on linear velocity.
BACKGROUND OF THE I~VENTIoN
In information recording media such as magnetooptical recording discs comprising a substrate and thereon a recording layer and a metallic layer and capable of -lS rewritlng information, it is to be desired that the dependence of the recording power on linear velocity is made small so that the recording power for recording information in said media does not largely vary with the inner peripheral and outer peripheral portions of the medium.
Usually, in the information recording medium such as the magnetooptical recording disc, a metallic layer is -formed, in addition to a magnetooptical recording layer, on a substrate. The metallic layers which have been used so ~ --far in the information recording media of the type such as magnetooptical recording discs are composed of nickel alloys, aluminum metal or aluminum alloys containing O.l-. . , , : ,.
10% by weight of titanium. However, the metallic layers composed of aluminum metal or aluminum-titanium alloys had such a disadvantage that they are poor in corrosion resistance and cannot withstand a long term-service.
The metallic layers composed of nickel alloys had also such a serious disadvantage that the recording power required at the time of writing information in the information recording medium largely varies with the inner peripheral and outer peripheral portions of said medium, -- -and thus the dependence of the recording power on linear velocity is still large.
With the view of developing information recording media which are excellent in corrosion resistance or long-term stability and which are small in llnear dependence of the recording power on linear velocity, the present inventors prosecuted extensive researches to find that the information recording media having a metallic layer composed of an aluminum alloy containing at least hafnium are excellent in corrosion resistance and small in 20 dependence of the recording power on linear velocity. -Thus, the present invention has been accomplished.
OBJ~CT OF THE I NVENTIQ~ -The present invention is intended to solve such problems associated with the prior art as mentioned above, and an object of the invention is to provide information recording media which are excellent in corrosion resistance ~- -~' ' ' ' ''',,"'.~'' ''','"'',''"', ,'' ~; .
and small in dependence of the recording power on linear velocity.
SUMMARY OF THE INVENTION
The information recording medium of the present invention has a recording layer and a metallic layer on a substrate. Broadly speaking, characteristic according to the invention is that the metallic layer is composed of an aluminum alloy that contains, in addition to aluminum, hafnium or niobium or both in an amount of 0.1 to 10 atom% based on the aluminum alloy as an essential element. The alloy may contain other metals such as chromium, titanium and magnesium. The total amount of these metals including hafnium or niobium is 15 atom%
when magnesium is included or is 10 atom% when magnesium is not included.
In a first embodiment, the metallic layer is composed of an aluminum alloy containing at least one element selected from among hafnium (Hf) and niobium (Nb) in an amount of 0.1-10 atom% based on all atoms constituting aluminum alloy layer.
In a second embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium and 0.1-5 atom% of chromium based on all atoms constituting aluminum alloy -layer, the combined content of said hafnium and chromium being less than 10 atom%.
In a third embodiment of the information recording -medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium, 0.1-5 atom%
of chromium and 0.1-9.5 atom% of titanium based on all atoms .
.. . . .
', ' , ' '' ' ',' '; ':' "., , ~, ' , .
,, , , ". ~ , constituting aluminum alloy layer, the combined content of said hafnium, chromium and titanium being less than 10 atom%.
In a fourth embodiment of the information recording medium of the invention, the metallic layer is composed of an --aluminum alloy containing 0.5-5 atom% of hafnium and 0.5-5 atom%
of titanium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium and titanium being 1-5.5 atom%.
In a fifth embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium and 0.1-10 atom% of magnesium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium and magnesium being less than 15 atom%.
In a sixth embodiment of the information recording :
medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom%
of magnesium and 0.1-10 atom% of titanium based on all atoms ,-constituting aluminum alloy layer, the combined content of said hafnium, magnesium and titanium being less than 15 atom%.
In a seventh embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom%
of magnesium and not more than 10 atom% of chromium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium, magnesium and chromium being less than 15 atom%.
~, : , . . . .
...
,., ,. , ~ ,, . , ,j " . , .
: ',, - . ~ "; , . ... .
.,: ., In an eight embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom~
of magnesium, 0.1-10 atom% of titanium and less than 10 atom~ of chromium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium, magnesium, titanium and chromium being less than 15 atom%.
The information recording medium of the present invention as illustrated above, which individually have a metallic layer composed of an aluminum alloy containing at least hafnium are excellent in corrosion resistance, small in the dependence of the recording power on linear velocity and excellent in performance of protecting the recording layer.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a rough sketch of one embodiment of the information recording medium in cross section of the present invention.
Fig. 2 is a rough sketch of another embodiment of the information recording medium in cross section of the present invention.
,~ ,, ~, "
,i' ' ' ' ',' ";,', ,', ;,, , " '' ' ", ' ' ' ' ' ' ''.' '',.' ' '' ' ' " , ' ', ' , ,, ' ' , ~ , ,, , ~r ', 1 .... Information recording medium 2 .... Substrate 3 .... Recording layer 4 .... Metallic layer 5 5 .... Protective film DETAILED DESCRIPTION OF THE INV~NTION
The information recording media of the present invention are illustrated below in detail.
Fig. 1 is a rough sketch of the information recording -medium in cross section of one embodiment of the invention, ' and Fig. 2 is also a rough sketch of the information recording medium in cross section of another embodiment of the invention.
In the information recording media of the invention, the information stored in said recording media is read out by means of light such as laser beam. Information recording media of this type include, in concrete, --postscript type optical disc capable of additional recording but incapable of erasing information recorded, rewriting type optical discs such as magnetooptical recording discs and phase change discs, capable of recording information as well as of erasing and reproducing the information recorded.
As can be seen from Fig. 1, for example, in an information recording medium 1 of the invention, a 2 ~ r ~3 ~ ,J
recording layer 3 and a metallic layer 4 are formed on a substrate 2 in that order.
Materials for the above-mentioned substrate 2 used in the invention are not particularly limited to specific ones. However, when laser beam is incident upon the substrate 2 (from the direction of an arrow A), the materials used therefor are preferably those which are transparent. Besides inorganic materials such as glass, aluminum and the like, such transparent materials include, for example, organic materials such as poly(methyl methacrylate), polycarbonate, polymer alloys of polycarbonate with polystyrene, such cycloolefin random copolymers as disclosed in U.S. Patent No. 4,614,778, such cycloolefin random copolymers (A) as mentioned below, poly-4-methyl-1-pentene, epoxy resins, polyether sulfone, polysulfone, polyether imide and the like. Of these organic materials, preferred are poly(methyl methacrylate), polycarbonate, such cycloolefin random copolymers as disclosed in U.S. Patent No. 4,614,778 and the cycloolefin 20 random copolymers (A) as mentioned below. -From the standpoint of good adhesion particularly to the recording layer and a small double refractive index, particularly desirable materials for the substrate used in the present invention are cycloolefin random copolymers (A) of ethylene and a cycloolefin represented by the following general formula lI], [I-a] or [I-b].
2 ~ r3 ~
~ n ' ' [I ]
wherein n is O or a positive integer, Rl to Rl2 are the same or different, and each reperesents a hydrogen atom, a halogen atom or a hydrocarbon group and R9 to Rl2, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have double bond or bonds, or R9 and Rl or Rll and Rl2, when taken together, may form an alkylidene group.
Further explanation of the cycloolefin represented by lS the general formula [I] will be given below. The cycloolefin represented by the general formula [I] may also be represented by the following general formula [I-a]. -General formula .
i I ~ ...[I-a]
In the general formula [I-a], n is O or 1, m is O or po8itlve integer, R1 to R18 represent each a atom or a . .
,. .. ..
.
~, . . ... ..
2~,3~
group selected from the group of a hydrogen atom, a halogen atom and a hydrocarbon group.
R15 to R18, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have 5 double bond or bonds.
Further more, R15 and R16, or R17 and R18, when taken together, may form an alkylidene group.
~
n~ n~
n 1 0 (C112)p n~ I
nl2 n )~J~n1 n-~ n n ...[I-b]
20 wherein p is an integer of at least 0, q and r are each 0,1 -or 2,R1 to R15 represent each an atom or a group selected from the group of a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group -and an alkoxy group, and R5 (or R6) and R8 (or R7) may be bonded together directly without an intermediate group or through an alkylene group of one to three carbon atoms. :
'.': '., ' . ,',' ' ,, ', ,'' :,' ' ' , ,',';' ,''': . . ' ' '' .. . ,:, ~ ' :,,' ,- , ," ,,, ,,. ', , , . ,: : ,,'" ,', :
' ~' ' ,''' ''' ' '' ', '"'.', '',,-' ",' ~'" .''' ' ' ... . .. . . ..
2 ~
I o The concrete example of the cycloolefins represented by the general formula [I] includesl,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, such octahydronaphthalenes as 2-methyl-1,4,5,8-dimethano-1,2,3,9,4a,5,8,8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-propyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-chloro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-bromo-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2,3-dichloro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-cyclohexyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-n-butyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-isobutyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, etc.
Furthermore, the cycloolefin represented by the general formula [I] includes, bicyclol2,2,1]hepto-2-en derivatives, tetracyclo[4,4,0,12 5,17 10]-3-dodecene derivatives, hexacyclol6,6,1,13.~,110.13,o2.7,o9.14]_4_ heptadesene, derivaties, "
' ~'., ' ' ;., , ,' .
,: , , ..
I 1 2~ J~
octacyclo[8~8~o~l2-9~l4 7~lll.l8~ll3~l6~o3~8~ol2 docosene derivaties, pentacyclo[8,8,0~l2 9~l4 7~ 8~ll3.l6~o3.8~ol2.
docosene derivatives, 5 pentacyclo[6,6,1,13 6,02 7,09 14]-4-hexadecene derivatives, heptacyclo-5-icosene derivatives, heptacyclo-5-henicosene derivatives, toricyclo[4,3,0,12-5l-3-decene derivatives toricyclol4,3,0,12 5]-3-undecene --derivatives, pentacyclo[6,5,1,13 6,02-7,09-13]-4-pentadecene 0 derivatives, pentacyclopentadecadiene derivatives, pentacyclo[4,7,0,12 5,o8 13,19 12]-3-pentadecene derivatives, pentacyclo[7~8~0~13 6~o2 7~110 17~oll~l6~112~15]_ 9-icosene derivatives, and nonacyclo~9,10,1,1,4 7,o3~8,o2~10~o12.21~113.20~ ol4.l9~ 115.18l_ 5-pentacosene derivatives.
The concrete examples of such componds as mentioned above are illustrated hereunder. - -,, , , , , - , , , :,, : ,., ,,, ",, ., " ..
, . . .. . ............ . . .. . . ... . . .
' ;,, , - , ', . , ' '' ' "''~ '' '' ' : :, , 1 2 2 ~
Bicyclo [2,2,1]hept-2-ene derivatives such as:
¢~ Bicyclot2,2,1]hept-2-ene 0--C ll, 6-Methylbicyclo~2,2,1]hept-2-ene 1~c 1l 5,6-Dimethylbicyclo[2,2,1]hept-2-ene C 1-1 " .
1 -Methylbicyclo[2,2, 1 ]hept-2-ene 1 5 ¢~ C 2 H ~ 6-Ethylbicyclo[2,2,1]hept-2-ene ,~n C4~1P
W 6-n-Butylbicyclo[2,2,1]hept-2-ene 2 0 ~ i C, 11 a Uw 6-Isobutylbicyclo[2,2, 1 ]hept-2-ene ~C H "
7-Methylbicyclo[2,2, 1 ]hept-2-ene: -,, . , ~ , . . ..... . ....... . ...... .
, ,. ., , , , , ,. ,,, ~ , . . . . .
1 3 2~3~
Tetracyclo[4,4,0,125,17 l0]-3-dodecene derivatives such as:
¢~ Tetracy¢10[4,4,0,12s,17 10]-3-dodecene S c }1, ~)~ 5,1 0-Dimethyltetracyclo [4,4,0,125,17 10]-3-dodecene C 1-1 !1 ' C 1-1" C ~J
~ 2, 1 0-Dimethyltetracyclo-~J 14,4,0,12-5,17-10]-3-dodecene -C }I a C 11 ~
If ~ 1 1,12-Dimethyltetracyclo-1 5 ~/J [4,4,0,12 5,17-10]-3-dodecene C 11, :
C 1 1, 2,7,9-Trimethyltetracyclo- -~(~ [4,4,0,12-5,17-10~-3-dodecene cll, C1~;, , a~ C 21~ r 9-Ethyl-2,7-dimethyltetracyclo-~ [4,4,0,125,17 l0]-3-dodecene ~ , C 1~ J
2 S C 11, c 1l l 9-1sobutyl-2,7-dimethyltetracyclo- : -~CII,C jl [4,4,0,1-5,1710]-3-dodecene .. , ,, ~ , : ;i , ............... .
,~,, ,,, ,~ , " " " , ,, , "~, .
1 4 ~ J .
C ~IJ C IIJ
~C lt 9,11,12-Trimethyltetracyclo-~VJ [4,4,0,12-5,17-10]-3-dodecene C I I ~ C l~ ~
~ C 2 11 O 9-Ethyl- 1 1,1 2-dimethyltetracyclo-4,4,0,12-5,17-10]-3-dodecene Cll ~ Cll ~, Cll "
1 O ~~CII2Cll 9-Isobutyl-11,12-dimethyltetracyclo-Gll J [4,4,0,12-5,17-10]-3-dodecene C IIJ
~ C 11 J 5,8,9,10-Tetramethyltetracyclo-~l~c 11, l4,4,0,12-5,17-10]-3-dodecene c tt .
8-Methyltetracyclo[4,4,0, ~¦ 125,17 lO]-3-dodecene C~l, 8-Ethyltetracyclo[4,4,0, 12-5,17-10]-3-dodecene C2~1~
':
2 5 ~ 8-Propyltetracyclo[4,4,0, ~V--C~117 12.5,17.101-3-dodcGene ", ' .' ', ,, ~ , , - , . 1 - ',. ... ' .. ' ' ' '. .. , , : ' ,' / , i ,, , ,, , ,, , , , ", . . . . ..
,, , , , , , , . .,, , , . , .. ,, ~ , .
1 5 2 ~
¢~ 8-Hexyltetracyclo[4,4,0, 1 2-5,17-l0]-3-dodecene C " 11 ", 1~ 8-Stearyltetracyclo[4,4,0, C, ~, 11 J T 1 2-5,17-l0~-3-dodecene ,~C 1I J 8,9-Dimethyltetracyclo[4,4,0, J 12-5,17-10]-3-dodecene - -~ C 11 " 8-Methyl-9-ethy1tetracyclo~4,4,0, ~\ C 21 1 ~ 1 2-5, 1 7- 1 l -3 -dodecene 8-Chlorotetracyclo[4,4,0, ~V~C I 12-5,17-l0]-3-dodecene - .-8-Bromotbtracyclo~4,4,0, ~B r 12-5,17-10]-3-dodecene 2 5 ~ 8-Fluorotetracyclol4,4,0, ~ F 12-5,17-10]-3-dodecene l 6 2 ~
~ C 1 8,9-Dichlorotetracyclo[4,4,0, U~C I 12-5,17-l0]-3-dodecene [~j,~ 8-Cyclohexyltetracyclo[4,4,0, 1 2-5,17-10]-3-dodecene 1 0 ¢~-C H 2 C 11 8-Isobutyltetracyclo[4,4,0, C' 11~ 125,17-10]-3-dodecene ~3 8-Butyltetracyclo[4,4,0, C ~ ll o l2-5,17-l0]-3-dodecene 8-Ethylidenetetracyclo[4,4,0, ~= C H C 1-1~ 12-5,17-10]-3-dodecene 8-Ethylidene-9-methyltetracyclo I~LcllCII~ 14,4,0,12-5,17-10]-3-dodecene 2 5 Call 5 8-n-Propylidene-9-ethyltetracyclo ~CIICI12CI13 [4,4,0,l2-5,l7-10]-3-dodecene 1 7 2 ~ 3 Cll ( Cll " ) 2 8-Ethylidene-9-isopropyltetracyclo ¢~= C II C ll ,, [4,4,0,12 5,17- 10~ -3 -dodecene C~ 11 n 8-Ethylidene-9-butyltetracyclo (~-CIICII~ [4,4,0,12-5,17-10]-3-dodecene ~ 8-n-Propylidenetetracyclo ~=C~ICII2CIIJ
[4,4,0,12-5,17-10] -3 -dodecene Cll jl ~ 8-n-Propylidene-9-ethyltetracyclo ~CIICII2CIIJ [4,4,0,12-5,17-10]-3-dodecene ~C211 ~ 8-Ethylidene-9-ethyltetracyclo [4,4,0,12 5,17-10]-3-dodecene '.:
CII~C113)2 8-n-Propylidene-9-isopropyltetracyclo[4,4,0,12 5,17-10]-3- .'-' ~CIICI12CII j, --dodecene -~
, "; ~, ,,, " ", , , , " , ,, " ,, , ", ., ,;", ~, , j ,, ~: , ,;, : . , . , , . :
1 8 2 ~ 3 ~ ~
~C 111~ 8-n-Propylidene-9-butyltetracyclo CIICll 2CII a [4,4,0,12-5,17-10]-3-dodecene S[~=C-CII a 8-Isopropylidenetetracyclo Cll J [4,4,0,12-5,17-10]-3-dodecene C11"
~C-C11 ~ 8-Isopropylidene-9-methyltetracyclo 10C11, [4,4,0,l2 5,l7-10l-3-dodecene ~=C-C11 " 8-lsopropylidene-9-ethyltetracyclo Cll ~ [4,4,0,12-5,17-10]-3-dodecene C11(C113)2 8-Isopropylidene-9-~LC-CI1~ isopropyltetracyclo[4,4,0,12-5,17 l0]-3- ~ -C11~ dodecene [~3-C-CH ~ 8-Isopropylidene-9-butyltetracyclo :-[4,4,0,l2-5,l7 10]-3-dodecene ~11, Hexacyclo[6~6~1~l36~ll0 l3~o2.7~o9~l4]-4-heptadecene derivates such as:
l 9 [~ HeXaCYCIO[6~6~1~13~6~l~0~13 027 09141 ~) 4-heptadecene 5C 11~ 12-Methylhexacyclo[6,6,1,136, ¢~1 110 13,02 7,09 l4]-4-heptadecene C 2 1I r ~l 12-Ethylhexacyclo[6,6,1,13 6, ~ 110 13,02 7,09 14]-4-heptadecene -C IIJ
~C 1~ 2 C 1l 12-lsobutylhexacyclo[6~6~1~13~6~ , -'V~-VJ C 11 110 13,02 7,09-14]-4-heptadecene 1 5 ' '"' "
C IIJ C 11~ 1,6,10-Trimethyl-12-isobutyl- --¢~~C 112 C 1I hexacyclo[6,6,1,13 6,110 13 02 7 o9 14]-C H J C ~ C 1I J 4-heptadecene Octacyclol8,8,0,129,147,1,11 l8,113 l6,038,0l2-l7]-S-docosen derivates such as:
~ Octacyclo[8,8,0,l2.9,l4.7,l,ll.l8, ~ 113.I6~O3.8~OI2-I7]-5-dOCOSene 2a~
CllJ 15-Methyloctacyclo[8,8,0,12 9,14-7, (~1 1,11.18, 113 16,o3 8,0l2 l7~-S-docosene S 1~ C211~ 15-Ethyloctacyclo[8,8,0,12-9,14-7, ~/J~/,~/J~/J I 11.18, 1l3~l6~o3~8~ol2~l7]-s-docosene:
pentacyclo[6,6, 1,13-6,02-7,09-14] -4-hexadecene 10 derivates such as:
n~ Pentacyclol6~6~ 3~6~o2~7 09-14] 4 hexadecene C 11~ C 11~
~ ~ ~ 1,3-Dimethylpentacyclo[6,6,1, [ ~ ~J 13 6,02 7,09-l4]-4-hexadecene c 11 , 2 0 ~ 1 ,6-Dimethylpentacyclo[6,6, 1, ~/~ 13-6,02-7,09 l4]-4-hexadecene c 11 , 15 ,1 6-Dimethylpentacyclol6,6, 1, W/~J 136,02-7,09 l4]-4-hexadecene ,, . ,,, , .,,,, , ,, ",, ", - ." . , ,, - : , " .
2 ~J
heptacyclo-5-icosene derivates or heptacyclo-t-henicosene derivates such as:
~/~1/~ Heptacyclo[8,7,0,129,14 7,11l l7, 5 ~ ~`J 03 8 012 l6]-5-icosene 1~1'`1 Heptacyclo[8,8,0,12.9,l4.7,lll.l8, ~ 03 8,0l2 17] -S -henicosene ,.. . .
toricyclo[4,3,0,12 5]-3-decene derivatives such as:
I~J Tricyclo[4,3,0,12-5l-3-decene c }I , J~ 2-Methyl-tricyclo[4,3,0, 1 2-5]-3-decene ll)~
~ S-Methyl-tricyclo[4,3,0,12-s]-3-decene:
C 11 . . ' . .
-,' '-", . . . .....
tricyclo[4,4,0,12 5l-3-undecene derivatives such as:
¢~) Tricyclo~4,4,0,1~5]-3-undccene C 11, ~1~ 10-Methyl-tricyclo[4,4,0,12-s]-l~) 3-undecene:
pentacyclo[6,5,1,13 6, 02 7,09-13]-4-pentadecene derivatives such as:
Pentacyclo[6~s~ 3.6, ~V~ 02 7 09 l3]-4-pentadecene c 11. c 11.
1,3-Dimethylpentacyclo[6,5,1,13-6, - -l~V 02 7,09-l3]-4-pentadecene c 11 , ¢ 1~6-Dimethylpentacyclo[6,5,1,13 6, ~/~ 02-7,09-13]-4-pentadecene cll.
C 11. C 1-1-14,15-Dimethylpentacyclol6,5,1,13-6, ~J o2-7,og 13]-4-pentadecene:
7~
,, , , - , .. , " . , ; . , ., ,: ,. . . .. . .
3? ~ J
diene compounds such as:
~ Pentacyclol6,5,1,13-6, 1 02.7,09 13~-4,10-pentadecadiene:
Pentacyclo[7,4,0,12-5,08-l3,19-12]-3-pentadecene derivatives such as:
,'.
Pentacyclo[7~4~o~l2.s~o8.l3~ls.
pen tadecene CllJ
f ~ Methyl-substituted pentacyclo ~V [7,4,0,12 5,08-13,19-12]-3-pentadecene 20 heptacyclo[8,7,0,13 6,02-7,110 17, 011-16,112 l5]-4-icosene derivatives such as:
Heptacyclo[8,7,0,13-6,02-7,1l0.17~ .
~ 0 1 l-16, 1 l2-l5] -4-icosene ' ' " ' 3, C ~I J C 1~ J Dimethyl-substituted heptacyclo ~1~ [8,7,0,136,02.7,110.17,01l.l6,1l~l5]-4 ~ ~V icosene S nonacyclo[10,9,1,14-7,03-8,02.lo~ol2.2l~ 113.20,014.19,115.18] 5 pentacosene derivatives such as:
NonacyclollO,9,1,14.7,o3.8,o2.lo,ol2,2 ~V 1 l3.20,ol4.19,1 1s.l8]-5-pentacosene C 11 ~ C f 1 3 Trimethyl-substituted nonacyclo 1lo~9~l~l4 7~o3 8~o2 lo~ol2.2l~ll3.2 C ~1 ~ 0l4.l9, l 15.18] 5 -pentacosene " , , , ,, , ," ~ , ~, , ", , ", . , . s,,,, .. . , . , , . , ' ..
The following compounds can be mentioned as concrete examples of cycloolefins represented by the formula [I-bJ.
~ 5-Phenylbicyclo[2,2,1]hept -2-ene 0 ~ 5-Methyl-5-phenylbicyclo [2,2,1~ :
C H, hept-2-ene 15 ~ C H 2 ~ 5-Benzylbicyclo[2,2,1]hept-2-ene ~ 5-Tolybicyc1o[2,2,l]hept-2-ene ~ 1,4-Methano-l,la,4,4a- -tetrahydrofluorene , ' : ,,'',, , ;', ' ' ', " ~ ' ' ' '~' '''' 1,4-Methano-1,4,4a,5,10,10a-hexahydroanthracene Cyclopentadiene-acenaphthylene ~ addition products ~ S-(a-naphthyl)blcyclo[2,2,1]hept-:' ~
.
, 3,~
, The cycloolefin random copolymers (A) comprise ethylene units and the above-mentioned cycloolefin units a~
the essential components as aforesaid, however, if necessary, in addition to these two essential components, said copolymers may contain other copolymerizable unsaturated monomer components so long as they will not throw hinderances in the way of accomplishing the object of the present invention. The unsaturated monomers which ~ay be copolymerized, if necessary, with the copolymer~ (A) may include,for example, alpha-olefins having from 3 to 20 carbon atoms such as propylene, 1-butene, 4-methyl-1-. .
pentene, 1-hexene, 1-octene, l-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene which may be used in an amount of up to an equimolar to the ethylene component unit in the resulting random copolymer.
In the cycloolefin random copolymer ~A] having a . -softening point (TMA) of at least 70C, the recurr~ng units ~-la] derived from ethylene are present in an amount of from :
40 to 85 mol%, preferably from 50 to 75 mol%, while the .
recurring units lb] derived from the cycloolefin are present in an amount of from 15 to 60 mol%, preferably from ~
25 to 50 mol%, and these recurring units [a] and [b] are arranged at random in the substantially linear chain of the copolymer lA]. The molar percentage of the recurring units [a] and [b] were determined by 13C-NMR. The fact that this cycloole~in random copolymer ~A] is completely soluble in 2 ~3 decalin at 135C confirms that it is substantially linear and free from a gel-forming crosslinked structure.
The cycloolefin random copolymer [A] has an intrinsic viscosity [~] of from O.OS to 10 dl/g, preferably from 0.08 5 to 5 dl/g as measured in decalin at 135C.
The softening temperature (TMA) of the cycloolefin random copolymer [A] as measured by a thermal mechanical analyzer is at least 70C, preferably from 90 to 250C, and further preferably from 100 to 200C. The softening temperature ~TMA) referred to above was determined by monitoring thermal deformation behavior of a 1 mm sheet of the copolymer [A] using a thermomechanical analyzer manufactured and sold by Du Pont. More specifically, a quartz needle was vertically placed on the sheet under a load of 49 g and the assembly was heated at a rate of 5C/min, and a temperature at which the needle penetrated into the sheet by the depth of 0.635 mm was taken as TMA.
This cycloolefin random copolymer [A] has a glass transition temperature (Tg) of normally from 50 to 230C, preferably from 70 to 210C.
The crystallinity of this cycloolefin random copolymer lA] as measured by X-ray diffractometry is normally from 0 to 10%, preferably from 0 to 7~, and further preferably from 0 to 5%.
The cycloolefin copolymers (A) constituting the cycloolefin random copolymer composition used in the pre~ent invention for forming the substrate may all be -" ,;"",, .,,. , , ,~., , , , ' .. ,'': ' .:, ' , : ~' 2 ~
prepared by the processes proposed by the present inventors in Japanese Patent L-O-P Publns. Nos. 168708/1985, 120816/1986, 115912/1986 and 115916/1986, 252406/1987, 252407/1987, 271308/1986 and 272216/1986, while suitab~y S selecting the conditions.
Furthermore, in the present invention, there may also be used as the substrate material a cycloolefin random copolymer composition comprising a cycloolefin random copolymer [A] prepared by copolymerizing ethylene with a cycloolefin represented by the following formula [I~, [I-a or [I-b] and having an intrlnsic viscosity 1~] of 0.05-10 dl/g measured in decalin at 135C and a softening temperature (TMA) of at least 70C, and a cycloolefin random copolymer [B] prepared by copolymerizing ethylene lS with a cycloolefin represented by the formula lI~, [I-a] or lI-bl and having an intrinsic viscosity [~] of 0.05-5 dl/g measured in decalin at 135C and a softening temperature (TMA) of less than 70C.
Furthermore, the substrate of the magnetooptical recording media according to the invention may be made of polymers having recurring units of the general formula ~III] resulting from ring opening of the cycloolefin monomers [I], or polymers having recurring units of the general formula [IV] resulting from hydrogenation of the 25 units [III]. -. .
, -,,,: , , , , , , ,, ' ' ' " , ' '' ', ' ' , '' , ' ' ' ' ~, ,, . , ' , ' ' ' I I I I I
~ ' ' ~ IVI
In the general formula lIII] or lIV~, n and Rl to R12 nre as deflned ln the general formula IIl.
~ thlckness of the aubstrate, though not partlcul~rly llmlted, la preferably 0.5-5 mm and especlally l 2 mm.
In the lnventlon, matorlals for the recordlng layer 3 are not partlcularly llmlted to spe¢lflc ones. However, when therecording layer-3 used is a magnetooptical recording layer havlng a monoaxlal anosotropy perpendlcular to the layer surface, thls recordlng layer 3 la preferably composed of at least one member selected from amonq (1) 3d trans1tion metals and at least one element selected from among tl~i) rare earth elementa, or compoaed of at leaat one member selected from among ti) 3d tran~ltlon metals, tll) a corroalon-reslstant metal, and at least one element selected from smong (ill) rare earth elements.
~, 2 ~ 3~-~
The 3d transition metals used include Ee, Co, Ti, V, Cr, Mn, Ni, Cu and zn. Of these metals, preferred is Fe or Co, or are both of them.
The corrosion-resistant metal (ii) is capable of improving oxidation resistance of this magnetooptical recording layer as the recording layer 3 by incorporation into this recording layer 3 of said corrosion-resistant metal. Such corrosion-resistant metal used includes Pt, Pd, Ti, Zr, Ta, Mo, Nb and Hf. Of these metals, preferred 0 are Pt, Pd and Ti, and particularly Pt or Pd, or both of them.
The rate earth elements (iii) used lnclude, for example, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, La, Ce, Pr, Nd, Pm, Sm and Eu. Of these elements, preferred are Gd, Tb, Dy, Ho, Nd, Sm and Pr.
Such magnetooptical recording layer as mentioned above -desirably contains the 3d transition metal (i) in an amount of 30-85 atom%, preferably 40-70 atom%, the corrosion-resistant metal (ii) in an amount of less than 30 atom%, preferably 5-25 atom%, and the rare earth element (iii) in an amount of 5-50 atom~, preferab~y 25-45 atom%.
When the recording layer 3 used is other than the magnetooptical recording layer, for example, said recording layer is a phase change type recording layer, this recording layer 3 is composed of such an alloy film, for example, as consisting essentially of Te or Se, and of Te-Ge-Sb alloy fllm, In-Sb-Te alloy film Te-Ge-Cr alloy film "
,,' "' ,-', ' ' ' " ,. '`, ' ,' ,, ', ' ~ : ' , -, ., -" ,', ', , ,. ~ , , ", . . ....
,, . , , , : , .
.
,,, , , :, , .
.
or Te-Ge-Zn alloy fllm. Further an organlc dye fllm composed of polymethlne compounds or cyanlne compounds may al~o be used as the phase change type recording layer.
A thlcknes~ of the recordlng lnyer 3, though not partlcularly limited, is 50-5000 A, preferably 100-2000 A.
In the flr~t em~odiment o~ the present lnventlon, the metalllc layer ls formed from an alumlnum alloy contalnlng 0.1-10 atom~ of at least one element (metal) selected from among hafnlum and nioblum.
0 Concretely, the metalllc layer 4 19 composed of an alumlnum alloy contalnlng 0.1-10 atom%, preferably 1-6 atom% of hafnlum ~llf), an alumlnum alloy contalnlng 0.1-10 atom~, preferably 1-6 atom~ of nloblum (Nb), or of an alumlnum alloy contalnlng both hafnlum and nloblum ln an 5 amount totallng to O.l-10 atom~. -The metalllc layer 4 as mentloned above may contain small amounts of at least one of other metals ~elements) ln addltion to alumlnum, hafnlum and~or nloblum. Such other metal as mentloned above lnclude, ~or example, chromlum 20 ~Cr, only ln case of Al-Nb alloy), alllcon ~Sl), t~nt~lum ~-~Ta), copper ~Cu), tungston ~W)~ zlrconlum ~ZrJ, manganese ~Mn), magne~ium (Mg, only ln case of Al-Nb alloy) and vanadlum ~V). The amount of these other metals contalned, lf any, ln the metalllc layer 1~ usually less than 5 atom~, -preferably les~ than 2 atom~.
In the second embodiment . of the lnventlon, the metalllc layer is ~ormed from an alumlnum ,~', ' ' ' ~:
. 72932-67 .
alloy containlng 0.1~9.5 atom%, preferably 1-5 atom~ of hafnlum and 0.1-5 atom%, preferably 1-3 atom% of chromlum.
In thls aluminum alloy, the comblned content of haLnlum and chromium 1B preferably le~s than 10 atom~.
In the third embodiment of the lnventlon, the metalllc layer i9 formed from an aluminum alloy contalning 0.1-9.5 atom%, preferably 1-5 atom~ of hafnlum, 0.1-5 atom%, preferably 1-3 atom% of chromlum ~nd 0.1-9.5 atom~, preferably 1-5 atom~ of titanlum.
In this aluminum alloy, the combined content of hafnium, chromium and titanium 18 preferably les~ than 10 atom%.
The metallic layers of the 8econd and thlrd embodiments o~ the lnventlon as illu~trnted above may nl90 contain, in addition to the alumlnum, hafnium, chromium and tltanium, small amounts of a~ least one of other elements ~metals~. Such other elements (metal) lnclude, for example, silicon tSl),tantalum ~Ta), copper ~Cu), tungsten ~W), zirconlum ~Zr), manganese ~Mnl, and vanadlum ~V). The amount of these other elements (metals) contalned, if any, ln the metallic layer 1B
usually less than 5 atom%, preferably less than 2 atom~. -In the fourth embodiment of the invention, the metallic layer i~ formed from an aluminum alloy contalning 0.5-5 atom~, preferably 1-3 atom~ of hafnium, and 0.5-5 atom%, preferably 1-3 atom% of tltanlum.
,~ "
~ 72932-67 In thls alumlnum alloy, the comblned content of hafnium and t~tanlum 1~ 1-5.5 atom%, preferably 2-4 atom~.
The metalllc layer of the fourth embodiment of the lnvention as illustrated above may al90 contaln, in addition to aluminum, hafnlum and tltanlum, small amounts of at least one of other elements ~metals).
Such other elements ~metals) lnclude, for example, sillcon (Sl), tantalum ~Ta), copper ~Cu), tungsten (W), zlrconlum (Zr), manganese ~Mn), and vanadlum ~V). The amount of 0 these other elements ~metals) contained, if any, ln the metalllc layer is usually less than 5 atom~, prefer~bly less than 2 atom%.
In the flfth embodiment o~ tho invention, the metalllc layer is foxmed from an fllumlnum alloy contalning 0.1-10 atom%, preferably 1-5 atom% of hafnlum and 0.1-10 atom%, preferably 1-5 atom~ o~ -magnesium.
In this aluminum alloy, the comblned content of - -hafnlum and magnesium i~ le~s than 15 atom%, preferably 1- ~ -10 atom%.
In the sixth . embodiment -of the lnventlon, the metallic layer 13 formed from an aluminum alloy contalning 0.1-10 atom%, preferably 1-5 atom% of ~ -hafnium, 0.1-10 atom%, preferably 1-5 atom~ of magneslum and 0.1-10 atom~, preferably 1-5 atom% of tltanium.
A
. . .
In thls alumlnum alloy, the comblned content of hafnium, magne~lum and tltanlum 18 deslrably leas than 15 atom%, preferably l-lO atom%.
In the ~eventh embodiment of the lnventlon, the metalllc layor is formed from an alumlnum alloy contalnlng 0.1-10 atomt, preferably 1-5 atom~ of hafnlum, 0.1-10 atom%, preferably 1-5 atom% of magneslum and not more th~n 10 atomt, pre~erably O.l-10 atom~, more preferably 1-5 atom~ of chromlum.
0 In thl~ alumlnum alloy, the combined content of hafnium, maqneslum and chromlum la deslrably les~ than 15 atom%, preferably 1-10 atom~.
In the elghth embodiment of the lnventlon, the metalllc layer 19 formed from an aluminum t5 alloy containlng O.l-10 atom%, preferably 1-5 atom% of hafnlum, O.l-lO atom~, pre~erably 1-5 atom~ of m~gneslum, lesa than 10 atom%, preferably 1-5 atom% of chromlum and O.l-10 atom%, preferably 1-5 atom% of tltanlum.
In this alumlnum alloy, the combined content of hafnium, magnesium, chromlum and titanlum 1~ deslrably lesJ
than 15 atom%, preferably l-lO atom%.
In the flfth, slxth, seventh and elghth embodiments of the lnventlon a9 lllu~trated above, the metallic layers may each contaln small amounts of at least one of other elements ~metals) ln additlon to hafnlum, mAgnesium, titanlum and chromlum. Such ~mall amounts of other elements ~metals) include, for example, sil~con ~Sl), ., , : , .... .
i , , ,, , ,, .",. :: , , , ,, ~ , ... .. . . . . ............. . . .
' '''~ ' ' ~'''` ' '' '', ,' "' ',' ' :
" .~ , ~
. .
.
tantalum (Ta), copper (Cu), tungsten (w), zirconium ~Zr), manganese (Mn) and vanadium ~v). The amount of such other elements (metals) contained, if any, in the metallic layer is usually less than 5 atom%, preferably less than 2 atom%
A thickness of the above-mentioned metallic layers i8 100-5000 A, preferably 500-3000 A and especially 700-2000 A.
The metallic layers used in the present invention fulfil their function as good heat conductive layers, and 0 in the presence of these metallic layers, the center portion of pits formed in the recording layers may be prevented from being excessively heated to high temperature -by the action of the recording laser beam applied thereto.
As the result, it is con~idered that the dependence of the information recording media of the invention on linear velocity is made small.
The metallic layers of the invention which are also excellent in corrosion resistance have such a characteristic feature that the dependence of the information recording media on linear velocity is small even after being used for a long period of time, and that said metallic layers are excellent in performance of protecting the recording layers.
The structure of the information recording media of the invention shown in Fig. 1 is given by way of illustration but not of limitation. For instance, they may -~
be prepared by providing a protecting film (enhancing film) -' 5 on the aforementloned substrate 2 and then provlding further the recordlng layer 3 and the metalllc l~yer 4 ln that order. The protectlve film (enhanclng film) 5 ls formed desirably from Si3N4, SiNX ~O<x~4/3), AlN, ZnSe, znS, Sl or CdS, though not llmlted thereto. A thickness of this protective film is loo-aooo A, preferably about 300-1500 A. Of these materials used for formlnq the protectlve fllm, particularly preferred are Si3N4 and SiNX ~O<x<4/3) from a viewpolnt of crack reslstance.
0 The functlon of the protectlve fllm 19 to protect the recording l~yer and, at the same tlme, lt enhances the lnformatlon recordlng medium in sensltlvlty and functlons as an enhanclng fllm. Such a protective layer deslrably has a refractlve lndex larger than that of the substrate.
I5 The lnformatlon recordlng medla of the present lnventlon may be prepared by formlng on the substrate the recordlng layer and the metalllc layer and, lf necessary, the protectlve layer uslng such fllm-formlng methods, for example, vacuum depos~tlon, sputterlng, electron beam depo~ltion or the llke.
The lnformatlon recordlng medla of the present lnvent~on comprlslng the metalllc lnyer compoaed of a 2S speclflc aluminum alloy are excellent ln corroslon reslJtance, small ln the dependence of the recordlng power ,, , ,: ', -.. . . .. . .
38 2 ~
on linear velocity and in performance of protecting therecording layer.
The present invention is illustrated below with reference to examples, but it should be construed that the invention is in no way limited to those examples.
The term "optimum recording power" used in the following Examples designates a recording power with which writing signals at a frequency of 1 MHz and a duty factor of SO% are recorded and which makes mlnimum the secondary harmonics of signals reproduced from the recorded signals.
Recording media show a lower degree of dependence on the linear velocity when the information recording media show smaller difference of the optimum recording powers determined at different linear velocities.
1 5 ~m~.
Hereinafter, corrosion resistance of the metallic layer was examined first by the following procedure.
On a glass substrate, a metallic layer composed of an aluminum-hafnium alloy was deposited to a thickness of 700 2 0 A by the sputtering process using an aluminum-hafnium --~
composite target. The hafnium content in the above- --mentioned aluminum-hafnium alloy (layer) constituting the metallic layer as formed was 4 atom% and the alumium content was 96 atom%.
This metallic layer as formed was immersed for 4 hours at 60C in an aqueous solution containing 10% by weight of 80dium chloride, whereby the corrosion re8istance of the '"" "'""'" ' '' ', ' ' ' " " ~' '' ' ' , '' '''' -',,: ' ''' ' ' ~ '''', "" "' ' ', ',,. ' i' 2 ~
metallic layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the sodium chloride aqueous solution of said metallic layer.
Example 2 On a glass substrate, a metallic layer composed of an aluminum-niobium alloy was deposited to a thickness of 700 A by the sputtering process using an aluminum-niobium composite target. The niobium content in the aluminum-niobium alloy (layer) constituting the metallic layer as formed was 4 atom%.
This metallic layer was immersed four hours at 60C in an aqueous solution containing 10% by weight of sodium chloride, whereby the corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change -before and after the immersion in the sodium chloride aqueous solution of said metallic layer.
Comparative Example 1 On a glass substrate, a metallic layer composed of aluminum was deposited to a thickness of 700 A by the sputtering process using an aluminum target.
This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containlng 10% by weight of sodium chloride, whereby corrosion resistance of the metallic , " ', ,,,, ", , ",. . . . . .
, , , ,, , : , , - , :
layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer measured after the immersion in the aqueous sodium chloride solution of said metallic layer was lower by about 30% than that measured before said immersion.
E~m~
On a disk substrate composed of an amorphous copolymer of ethylene with l,4,5,8-dlmethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene ~structure formula:abbreviated to DMON hereinafter), the amorphou~ copolymer having 59 mol% of an ethylene unit content determined by NMR analysis, an intrinsic viscosity ~ of 0.42 dl/g measured in decalin at 135C and a softening temperature (TMA) of 159C~ were deposited successively a protective film composed of Si3N4 to a thickness of 1100 A and a recording layer composed of PtloTb2gFessCo6 to a thickness of 260A by the sputter$ng process, and thereon was deposited a metallic layer composed of an aluminum-hafnium alloy to a thickness of 700 A by the sputtering process u-Qing an aluminum-hafnium composite target. The hafnium content in the aluminum-hafnium alloy (layer) constituting the metallic layer was 4 atom% and the aluminum content was 96 atom%.
The information recording medium thus obtained was held for about 720 hours under the circumstanceQ of 80C
and a relative humidity of 85%, whereby corrosion J
resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said metallic layer under the circumstance of 80C and a relative humidity of 85%.
This fact means that the metallic layer are excellent in corrosion resistance and in performance of protecting the recording layer.
Example 4 Example 3 was repeated except that the metallic layer formed had a thickness of 500 A.
The information recording medium obtained was held for about 720 hours under the circumstances of 80C and a relative humidity of 85% to measure reflectance of said information recording medium, whereby the reflectance of said information recording medium did not change.
The optimum recording power of this information recording medium at a linear velocity of 5.7 m/sec was 3.7 mW, and the optimum recording power at a linear velocity of 11.3 m/sec was 5.2 mW.
Comparative Example 2 On a substrate used in the Example 3, were deposited successively a protective film composed of Si3N4 and a recording layer composed of Pt1oTb2gFessCo6 by the ... . . . . . . . . ....................... .. .
' ', , ,: , ,, , :.................... , ., .. : .
,, ., , , -, . . . .......................... . .
;:: . , ~. , ~ 7 sputtering process, and thereon was deposited a metallic layer composed of aluminum to a thickness of 700 A by the sputtering process using an aluminum target.
The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated ~ ~ r ro ~t~`o r~
l~ by measuring a change in reflectance of ~aid mctallic rCC~r d"~ 'j ~d, ~ .
1 0 lc~yt ~
The reflectance of said information recording medium measured after holding said recording medium was lower by about 15% than that measured before said holding.
~x~mple 5 Hereinafter, corrosion resistance of a metallic layer composed of an aluminum-hafnium-chromium alloy was examined by the followlng procedure.
On a glass substrate, was deposited a metallic layer composed of an aluminum-hafnium-chromium alloy to a -thickness of 1000 A by the sputtering process using an aluminum-chromium-hafnium composite target.
The hafnium and chromium contents of the metallic ' -layer thus formed were each 2 atom%.
This metallic layer was immersed for 4 hours at 60C
ln an aqueous solution containing 10~ by weight of sodium chloride, whereby corrosion resistance of the metallic " ,, .,",".,~ .,,, ' . . " ', . ,,,' ~,r~S ~ , ;J
layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer.
The number of pinholes observed in the metallic layer after the above-mentioned immersion was less than 50 pieces ~49 pieces) per unit surface area (5 cm x 5 cm).
Example 6 On a substrate used in the Example 3, were deposited successively a protective film (1100 A in thickneqs) composed of Si3N4 and a recording layer (260 A in thickness) composed of Pt1oTb2gFessCo6 by the sputtering process, and thereon was deposited a metallic layer (500 A
in thickness) composed of an Al-Cr-Hf alloy by the sputtering process using a composite target of Al-Cr-Hf.
The Cr and Hf contents in the Al alloy (layer) constituting the metallic layer obtained were each 2 atom%.
The information recording medium obtained was held for -about 720 hours under the circumstances of 80C and a relative humidity of 85%, whereby'corrosion resistance of the metallic layer and proLective function of the metallic layer for the recording layer were evaluated by measuring a ~J change in reflectance of the metallic layer and surface profile of the metallic layer.
, , , , , ~ ' , , ':, .' ' , , , ' ', , , , . . . . . . .. .
'~", ,''''''' .,''' '' ~'' ' ','' ,' "',','.,', '' ,, s 1, ~3 ~ ~
r rn~,t~ l~ n ~ ~ c, ~ r d ~ r>7 ~ ~
The reflectance of the metalllc layer did not change before and after holding the same under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information recording medium at a linear velocity of (5.7) m/sec was (3.6) mW, and the optimum recording power at a linear velocity of (11.3) m/sec was (5.3) mW.
On a substrate used in the Example 3, were deposited successively a protective film (1000 A in thickness) composed of Si3N4 and a recording layer (500 A in thickness) composed of PtloTb2gFessco6 by the sputtering process, and thereon was deposited a metallic layer (700 A
in thickness) composed of an Al-Cr-Hf alloy by the sputtering process using a composite target of Al-Cr-Hf.
The Cr and Hf contents in the Al alloy (layer) constituting ~ -the metallic layer obtained were each 2 atom%.
The information recording medium obtained was held for about 720 hours under the circumstances of 80C and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated by measuring a ) r ~ r~ r lz c c~r d, ~ 7 ~ e~
change in reflectance of the mctallic laycr and su~face profile of the metallic layer.
o r rn Q~ o n r e c ~ ~ J. r~ ~ ~ ~d The reflectance of the metallic l~ycr did not change before and after holding the same under the circumstances of 80C and a relative humidity of 85%.
" :. "
,~, . ,, ", . .. ..
.
Comparative Example 3 On a glass substrate, a metallic layer composed of an aluminum-chromium alloy was formed to a thicknes~ of 1000 A
by the sputtering process using an aluminum-chromium S composite target.
The chromium content of the metallic layer thus formed was 2 atom%.
This metallic layer was immersed for 9 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride.
After the 4-hour immersion, changes in reflectance and surface profile of the metallic layer were measured. The reflectance of the metallic layer thus measured decreased by about 2%.
The number of pinholes ob~erved on the metallic layer was about 70 pieces per unit film surface area (5 cm x 5 cm).
Comparative Example 4 A metallic layer containing 4 atom~ of chromium was obtained in the same manner as in Comparative Example 3 but using a compo~ite target of an al~minum-chromium alloy --different in composition from the composite target used in Comparative Example 3.
- This metallic layer was immersed in an aqueous sodium chloride solution in the same way as in Comparatlve Example 3 to measure changes in reflectance and surface profile of the metallic layer after the immersion thereof.
, i . , : , . ....................... .
,, , , , , , , ~,, ~, , ., ~ , ... . .
~ r~ h~
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer after the immersion S thereof was about 70 pieces per unit film surface area (5 cm x 5 cm).
Example 8 Hereinafter, corrosion resistance of the metallic layers composed of an aluminum-hafnium-titanium alloy was .
examined.
On a glass substrate, a metallic layer composed of an aluminum-hafnium-titanium alloy was formed by the sputtering process using a composite target of aluminum(Al)-hafnium(Hf)-titanium (Ti).
lS The titanium content of the metallic layer thus obtained was 1 atom%, and the hafnium content thereof was 2 atom%.
~ ,, ~ ,, This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride, whereby corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of -.
said metallic layer and surface profile of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer after the immersion -" ''.~",; '"',~''" "' ,' '" "",'"'',",' " ", ''','~'' ".' ' : ' ,: , , , ,, i .,, , ,"
thereof was less than 40 pieces (38 pieces) per unit film surface area t5 cm x 5 cm).
Example 9 A metallic layer containing 2 atom% of titanium and 1 atom% of hafnium was obtained in the same manner as in Example 8 but using a composite target composed of an aluminum-titanium-hafnium alloy different in composition from the composite target used in Example 8.
This metallic layer was immersed in the same manner as in Example 7 in the aqueous sodium chloride solution to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of the metallic layer after the immersion thereof.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of sald metallic layer, and the number of pinholes observed in the metallic layer after the immersion -was less than 40 pieces (33 pieces) per unit film surface area (5 cm x 5 cm). -, Example 10 On a substrate used in the Example 3, were deposited . , successively a protective film (1100 A in thickness) composed of Si3N4 and a recording layer ~260 A in thickne,~s) composed of Pt1oTb2gFessCo6 by the sputtering process, and thereon was deposited a metallic layer (500 A
/, f~ J COh~ 'fo~ f cor~ QJrO~ T,' ln thickness) composed of an Al-Hf-Ti alloy\by the ' ~
sputtering process using a composite target of Al-Hf-Ti. ~)~y ,' ' ' '"'"''-", :', " "' ' '" '' ' . ',,,,"', ~,, ;;, ;. , ':
: . , . ,, , , :
!5 The information recording medium thus obtained wa~
held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said recording medium under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information --recording medium at a linear velocity of (5.7) m/sec was (3.3) mW, and the optimum recording power at a linear velocity of (11.3) m/sec was (4.7) mW.
Comparative Example 5 A metallic layer containing 2 atom% of titanium was obtained in the same manner as in Example 8 but using a composite target of aluminum-titanium in place of aluminum-titanium-hafnium used in Example 8.
This metallic layer was immersed in the aqueous sodium chloride solution in the same way'as in Example 8 to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of sald metallic layer after the immersion thereof.
The reflectance of the metallic layer decreased by about 8% by the immersion of said metallic layer.
,. . , , . ,-., . . . ,.. , ~, . . . . .
,, ,, ,, . . i ,, - : . ',',...... ........... " ,' , .
, ,, , , , , , ' :'' ' ' ' ' ' .
2 ~
The number of pinholes observed in the metallic layer was 51 pieces per unit film surface area (5 cm x 5 cm).
Comparative Example 6 A metallic layer composed of an aluminum-titanium alloy containing 4 atom% of titanium was formed in the same manner as in Comparative Example 5.
This metallic layer was immersed in the same way as in Example 8 in the aqueous sodium chloride solution to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of said metallic layer after the immersion thereof.
The reflectance of the metallic layer decreased by about 2% by the immersion of said metallic layer, The number of pinholes observed in the metallic layer was more than 115 pieces per unit film surface area (5 cm x 5 cm)-ExamDle 11 On a substrate used in the Example 3, were deposited successively a protective film (1000 A in thickness) composed of Si3N4 and a recording layer (500 A in thlckness) composed of PtloTb2gFe55Co6 by the sputtering - -proce~s, and thereon was deposited a metallic layer (700 A
z~ (A cO,"~ JD~ /~ Hf COht~r>t ~ oto~7~o/ T~c~ t~ ~
D in thickne~-c) composed of an Al-Hf-Ti alloy\by the - :
sputtering process using a composite target of Al-Hf-Ti. --The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whèreby corrosion '"'''',''' ''"'"''',''', ,'''' 'i','""','''", '''''''.',"';, ;'"' .~'.' ~'':
2 ~
so resistance of the metallic layer and protective function of the metallic layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said recording medium under the circumstances of 80C and a relative humidity of 85%.
m~le 12 On a glass substrate, a metallic layer ~1000 A in .
thickness) composed of an aluminum-hafnium-magnesium alloy was formed by the sputtering process using a composite target of aluminum (Al)-hafnium (Hf)-magnesium (Mg).
This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride, whereby corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of said metallic layer and surface profile of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer was less than 30 pieces (25 pieces) per unit film surface area (5 cm x 5 cm).
~x~m~ 13-14 Metallic layers were formed in the same manner as in Example 12 but using composite targets as shown in Table 1.
,,,. . , , , ,, - . ; ~ , - . ,:,, ' '.,, . .",.~ . .. ~,.,: ' . .' `' .' ;' . : . ., . . - . . .
'., ' ., ' ,.' ; ,' : . '," ':' .' . , . ; ,:. ,, ,, . ' . . ',, ', , - .
,. ~ , ,, ., : ., s~
The atom content and the number of plnholes of the metallic layers thus formed are shown in Table 1.
' ' ,' ',''' i' ' ,, ,',''~ " ''' ', ' , ,: , ,' , ,, ,; , :, ,, ,,, ' ,, . ~ :: ,....... .
2 ~
Table 1 Composite target usedAtom content and (at%) Composition Number of of Metallic Mg Hf Ti pinholes not more Example 12 Al-Mg-Hf 4 4 - than 30 pieces (25 pieces) , not more Example 13 Al-Mg-Hf 4 2 - than 30 pieces (30 Pieces) .-. _ Less than Example 14 Al-Mg-Hf-Ti 4 2 1 30 pieces . (30 pieces) Comparative Example 7 Al-Mg 5 - _ 70 pieces .xample 15 On a substrate used in Example 3, were deposited successively a protective film (1100 A in thickness) composed of Si3N4, and a recording layer (260 A in thickness) composed of PtloTb2gFèssco6~ by the sputtering process, and was deposited thereon a metallic layer (500 A
in thickness) composed of an Al-Mg-Hf alloy by the sputterlng process using a composite target of aluminum (Al)-hafnlum (Hf)-magnesium (Mg). The Mg content was 4 "..
2 ~
atom% and the Hf content was 2 atom% in the Al alloy (layer) constituting the metalllc layer as formed above.
The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%.
The reflectance of the information recording medium did not change before and after holding the information recording medium under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information recording medium at a linear velocity of ~5.7) m/sec was ~4.0) mW, and the optimum recordlng power at a linear velocity of ~11.3) m/sec was ~5.6) mW.
Comparative Examplc 7 On a glass substrate, was formed a metallic layer ~looo A in thickness) composed of an aluminum-magnesium alloy by the sputterlng process using a composite target of aluminum-magnesium.
The magnesium content in the metallic layer thus obtained was 5 atom%.
This metallic layer was immersed for 4 hours at 60C ~-in an aqueous solution containing 10% by weight of sodium chloride.
The reflectance of the metallic layer immersed 25 decreased by about 2% by the above-mentioned immersion. -.. .
, ~ , , .
2 ~
The number of pinholes observed in the metallic layer was about 70 pieces per unit film surface area (5 cm x 5 cm).
TIT~E
INFORMATION RECORDING MEDIA
FIELD OF THE INVENTION
S This invention relates to information recording media having a metallic layer and more particularly to information recording media excellent in corrosion resistance or stability, and small in dependence of their recording power on linear velocity.
BACKGROUND OF THE I~VENTIoN
In information recording media such as magnetooptical recording discs comprising a substrate and thereon a recording layer and a metallic layer and capable of -lS rewritlng information, it is to be desired that the dependence of the recording power on linear velocity is made small so that the recording power for recording information in said media does not largely vary with the inner peripheral and outer peripheral portions of the medium.
Usually, in the information recording medium such as the magnetooptical recording disc, a metallic layer is -formed, in addition to a magnetooptical recording layer, on a substrate. The metallic layers which have been used so ~ --far in the information recording media of the type such as magnetooptical recording discs are composed of nickel alloys, aluminum metal or aluminum alloys containing O.l-. . , , : ,.
10% by weight of titanium. However, the metallic layers composed of aluminum metal or aluminum-titanium alloys had such a disadvantage that they are poor in corrosion resistance and cannot withstand a long term-service.
The metallic layers composed of nickel alloys had also such a serious disadvantage that the recording power required at the time of writing information in the information recording medium largely varies with the inner peripheral and outer peripheral portions of said medium, -- -and thus the dependence of the recording power on linear velocity is still large.
With the view of developing information recording media which are excellent in corrosion resistance or long-term stability and which are small in llnear dependence of the recording power on linear velocity, the present inventors prosecuted extensive researches to find that the information recording media having a metallic layer composed of an aluminum alloy containing at least hafnium are excellent in corrosion resistance and small in 20 dependence of the recording power on linear velocity. -Thus, the present invention has been accomplished.
OBJ~CT OF THE I NVENTIQ~ -The present invention is intended to solve such problems associated with the prior art as mentioned above, and an object of the invention is to provide information recording media which are excellent in corrosion resistance ~- -~' ' ' ' ''',,"'.~'' ''','"'',''"', ,'' ~; .
and small in dependence of the recording power on linear velocity.
SUMMARY OF THE INVENTION
The information recording medium of the present invention has a recording layer and a metallic layer on a substrate. Broadly speaking, characteristic according to the invention is that the metallic layer is composed of an aluminum alloy that contains, in addition to aluminum, hafnium or niobium or both in an amount of 0.1 to 10 atom% based on the aluminum alloy as an essential element. The alloy may contain other metals such as chromium, titanium and magnesium. The total amount of these metals including hafnium or niobium is 15 atom%
when magnesium is included or is 10 atom% when magnesium is not included.
In a first embodiment, the metallic layer is composed of an aluminum alloy containing at least one element selected from among hafnium (Hf) and niobium (Nb) in an amount of 0.1-10 atom% based on all atoms constituting aluminum alloy layer.
In a second embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium and 0.1-5 atom% of chromium based on all atoms constituting aluminum alloy -layer, the combined content of said hafnium and chromium being less than 10 atom%.
In a third embodiment of the information recording -medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium, 0.1-5 atom%
of chromium and 0.1-9.5 atom% of titanium based on all atoms .
.. . . .
', ' , ' '' ' ',' '; ':' "., , ~, ' , .
,, , , ". ~ , constituting aluminum alloy layer, the combined content of said hafnium, chromium and titanium being less than 10 atom%.
In a fourth embodiment of the information recording medium of the invention, the metallic layer is composed of an --aluminum alloy containing 0.5-5 atom% of hafnium and 0.5-5 atom%
of titanium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium and titanium being 1-5.5 atom%.
In a fifth embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium and 0.1-10 atom% of magnesium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium and magnesium being less than 15 atom%.
In a sixth embodiment of the information recording :
medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom%
of magnesium and 0.1-10 atom% of titanium based on all atoms ,-constituting aluminum alloy layer, the combined content of said hafnium, magnesium and titanium being less than 15 atom%.
In a seventh embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom%
of magnesium and not more than 10 atom% of chromium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium, magnesium and chromium being less than 15 atom%.
~, : , . . . .
...
,., ,. , ~ ,, . , ,j " . , .
: ',, - . ~ "; , . ... .
.,: ., In an eight embodiment of the information recording medium of the invention, the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom~
of magnesium, 0.1-10 atom% of titanium and less than 10 atom~ of chromium based on all atoms constituting aluminum alloy layer, the combined content of said hafnium, magnesium, titanium and chromium being less than 15 atom%.
The information recording medium of the present invention as illustrated above, which individually have a metallic layer composed of an aluminum alloy containing at least hafnium are excellent in corrosion resistance, small in the dependence of the recording power on linear velocity and excellent in performance of protecting the recording layer.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a rough sketch of one embodiment of the information recording medium in cross section of the present invention.
Fig. 2 is a rough sketch of another embodiment of the information recording medium in cross section of the present invention.
,~ ,, ~, "
,i' ' ' ' ',' ";,', ,', ;,, , " '' ' ", ' ' ' ' ' ' ''.' '',.' ' '' ' ' " , ' ', ' , ,, ' ' , ~ , ,, , ~r ', 1 .... Information recording medium 2 .... Substrate 3 .... Recording layer 4 .... Metallic layer 5 5 .... Protective film DETAILED DESCRIPTION OF THE INV~NTION
The information recording media of the present invention are illustrated below in detail.
Fig. 1 is a rough sketch of the information recording -medium in cross section of one embodiment of the invention, ' and Fig. 2 is also a rough sketch of the information recording medium in cross section of another embodiment of the invention.
In the information recording media of the invention, the information stored in said recording media is read out by means of light such as laser beam. Information recording media of this type include, in concrete, --postscript type optical disc capable of additional recording but incapable of erasing information recorded, rewriting type optical discs such as magnetooptical recording discs and phase change discs, capable of recording information as well as of erasing and reproducing the information recorded.
As can be seen from Fig. 1, for example, in an information recording medium 1 of the invention, a 2 ~ r ~3 ~ ,J
recording layer 3 and a metallic layer 4 are formed on a substrate 2 in that order.
Materials for the above-mentioned substrate 2 used in the invention are not particularly limited to specific ones. However, when laser beam is incident upon the substrate 2 (from the direction of an arrow A), the materials used therefor are preferably those which are transparent. Besides inorganic materials such as glass, aluminum and the like, such transparent materials include, for example, organic materials such as poly(methyl methacrylate), polycarbonate, polymer alloys of polycarbonate with polystyrene, such cycloolefin random copolymers as disclosed in U.S. Patent No. 4,614,778, such cycloolefin random copolymers (A) as mentioned below, poly-4-methyl-1-pentene, epoxy resins, polyether sulfone, polysulfone, polyether imide and the like. Of these organic materials, preferred are poly(methyl methacrylate), polycarbonate, such cycloolefin random copolymers as disclosed in U.S. Patent No. 4,614,778 and the cycloolefin 20 random copolymers (A) as mentioned below. -From the standpoint of good adhesion particularly to the recording layer and a small double refractive index, particularly desirable materials for the substrate used in the present invention are cycloolefin random copolymers (A) of ethylene and a cycloolefin represented by the following general formula lI], [I-a] or [I-b].
2 ~ r3 ~
~ n ' ' [I ]
wherein n is O or a positive integer, Rl to Rl2 are the same or different, and each reperesents a hydrogen atom, a halogen atom or a hydrocarbon group and R9 to Rl2, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have double bond or bonds, or R9 and Rl or Rll and Rl2, when taken together, may form an alkylidene group.
Further explanation of the cycloolefin represented by lS the general formula [I] will be given below. The cycloolefin represented by the general formula [I] may also be represented by the following general formula [I-a]. -General formula .
i I ~ ...[I-a]
In the general formula [I-a], n is O or 1, m is O or po8itlve integer, R1 to R18 represent each a atom or a . .
,. .. ..
.
~, . . ... ..
2~,3~
group selected from the group of a hydrogen atom, a halogen atom and a hydrocarbon group.
R15 to R18, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have 5 double bond or bonds.
Further more, R15 and R16, or R17 and R18, when taken together, may form an alkylidene group.
~
n~ n~
n 1 0 (C112)p n~ I
nl2 n )~J~n1 n-~ n n ...[I-b]
20 wherein p is an integer of at least 0, q and r are each 0,1 -or 2,R1 to R15 represent each an atom or a group selected from the group of a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group -and an alkoxy group, and R5 (or R6) and R8 (or R7) may be bonded together directly without an intermediate group or through an alkylene group of one to three carbon atoms. :
'.': '., ' . ,',' ' ,, ', ,'' :,' ' ' , ,',';' ,''': . . ' ' '' .. . ,:, ~ ' :,,' ,- , ," ,,, ,,. ', , , . ,: : ,,'" ,', :
' ~' ' ,''' ''' ' '' ', '"'.', '',,-' ",' ~'" .''' ' ' ... . .. . . ..
2 ~
I o The concrete example of the cycloolefins represented by the general formula [I] includesl,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, such octahydronaphthalenes as 2-methyl-1,4,5,8-dimethano-1,2,3,9,4a,5,8,8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-propyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-chloro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-bromo-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2,3-dichloro-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-cyclohexyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-n-butyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, 2-isobutyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, etc.
Furthermore, the cycloolefin represented by the general formula [I] includes, bicyclol2,2,1]hepto-2-en derivatives, tetracyclo[4,4,0,12 5,17 10]-3-dodecene derivatives, hexacyclol6,6,1,13.~,110.13,o2.7,o9.14]_4_ heptadesene, derivaties, "
' ~'., ' ' ;., , ,' .
,: , , ..
I 1 2~ J~
octacyclo[8~8~o~l2-9~l4 7~lll.l8~ll3~l6~o3~8~ol2 docosene derivaties, pentacyclo[8,8,0~l2 9~l4 7~ 8~ll3.l6~o3.8~ol2.
docosene derivatives, 5 pentacyclo[6,6,1,13 6,02 7,09 14]-4-hexadecene derivatives, heptacyclo-5-icosene derivatives, heptacyclo-5-henicosene derivatives, toricyclo[4,3,0,12-5l-3-decene derivatives toricyclol4,3,0,12 5]-3-undecene --derivatives, pentacyclo[6,5,1,13 6,02-7,09-13]-4-pentadecene 0 derivatives, pentacyclopentadecadiene derivatives, pentacyclo[4,7,0,12 5,o8 13,19 12]-3-pentadecene derivatives, pentacyclo[7~8~0~13 6~o2 7~110 17~oll~l6~112~15]_ 9-icosene derivatives, and nonacyclo~9,10,1,1,4 7,o3~8,o2~10~o12.21~113.20~ ol4.l9~ 115.18l_ 5-pentacosene derivatives.
The concrete examples of such componds as mentioned above are illustrated hereunder. - -,, , , , , - , , , :,, : ,., ,,, ",, ., " ..
, . . .. . ............ . . .. . . ... . . .
' ;,, , - , ', . , ' '' ' "''~ '' '' ' : :, , 1 2 2 ~
Bicyclo [2,2,1]hept-2-ene derivatives such as:
¢~ Bicyclot2,2,1]hept-2-ene 0--C ll, 6-Methylbicyclo~2,2,1]hept-2-ene 1~c 1l 5,6-Dimethylbicyclo[2,2,1]hept-2-ene C 1-1 " .
1 -Methylbicyclo[2,2, 1 ]hept-2-ene 1 5 ¢~ C 2 H ~ 6-Ethylbicyclo[2,2,1]hept-2-ene ,~n C4~1P
W 6-n-Butylbicyclo[2,2,1]hept-2-ene 2 0 ~ i C, 11 a Uw 6-Isobutylbicyclo[2,2, 1 ]hept-2-ene ~C H "
7-Methylbicyclo[2,2, 1 ]hept-2-ene: -,, . , ~ , . . ..... . ....... . ...... .
, ,. ., , , , , ,. ,,, ~ , . . . . .
1 3 2~3~
Tetracyclo[4,4,0,125,17 l0]-3-dodecene derivatives such as:
¢~ Tetracy¢10[4,4,0,12s,17 10]-3-dodecene S c }1, ~)~ 5,1 0-Dimethyltetracyclo [4,4,0,125,17 10]-3-dodecene C 1-1 !1 ' C 1-1" C ~J
~ 2, 1 0-Dimethyltetracyclo-~J 14,4,0,12-5,17-10]-3-dodecene -C }I a C 11 ~
If ~ 1 1,12-Dimethyltetracyclo-1 5 ~/J [4,4,0,12 5,17-10]-3-dodecene C 11, :
C 1 1, 2,7,9-Trimethyltetracyclo- -~(~ [4,4,0,12-5,17-10~-3-dodecene cll, C1~;, , a~ C 21~ r 9-Ethyl-2,7-dimethyltetracyclo-~ [4,4,0,125,17 l0]-3-dodecene ~ , C 1~ J
2 S C 11, c 1l l 9-1sobutyl-2,7-dimethyltetracyclo- : -~CII,C jl [4,4,0,1-5,1710]-3-dodecene .. , ,, ~ , : ;i , ............... .
,~,, ,,, ,~ , " " " , ,, , "~, .
1 4 ~ J .
C ~IJ C IIJ
~C lt 9,11,12-Trimethyltetracyclo-~VJ [4,4,0,12-5,17-10]-3-dodecene C I I ~ C l~ ~
~ C 2 11 O 9-Ethyl- 1 1,1 2-dimethyltetracyclo-4,4,0,12-5,17-10]-3-dodecene Cll ~ Cll ~, Cll "
1 O ~~CII2Cll 9-Isobutyl-11,12-dimethyltetracyclo-Gll J [4,4,0,12-5,17-10]-3-dodecene C IIJ
~ C 11 J 5,8,9,10-Tetramethyltetracyclo-~l~c 11, l4,4,0,12-5,17-10]-3-dodecene c tt .
8-Methyltetracyclo[4,4,0, ~¦ 125,17 lO]-3-dodecene C~l, 8-Ethyltetracyclo[4,4,0, 12-5,17-10]-3-dodecene C2~1~
':
2 5 ~ 8-Propyltetracyclo[4,4,0, ~V--C~117 12.5,17.101-3-dodcGene ", ' .' ', ,, ~ , , - , . 1 - ',. ... ' .. ' ' ' '. .. , , : ' ,' / , i ,, , ,, , ,, , , , ", . . . . ..
,, , , , , , , . .,, , , . , .. ,, ~ , .
1 5 2 ~
¢~ 8-Hexyltetracyclo[4,4,0, 1 2-5,17-l0]-3-dodecene C " 11 ", 1~ 8-Stearyltetracyclo[4,4,0, C, ~, 11 J T 1 2-5,17-l0~-3-dodecene ,~C 1I J 8,9-Dimethyltetracyclo[4,4,0, J 12-5,17-10]-3-dodecene - -~ C 11 " 8-Methyl-9-ethy1tetracyclo~4,4,0, ~\ C 21 1 ~ 1 2-5, 1 7- 1 l -3 -dodecene 8-Chlorotetracyclo[4,4,0, ~V~C I 12-5,17-l0]-3-dodecene - .-8-Bromotbtracyclo~4,4,0, ~B r 12-5,17-10]-3-dodecene 2 5 ~ 8-Fluorotetracyclol4,4,0, ~ F 12-5,17-10]-3-dodecene l 6 2 ~
~ C 1 8,9-Dichlorotetracyclo[4,4,0, U~C I 12-5,17-l0]-3-dodecene [~j,~ 8-Cyclohexyltetracyclo[4,4,0, 1 2-5,17-10]-3-dodecene 1 0 ¢~-C H 2 C 11 8-Isobutyltetracyclo[4,4,0, C' 11~ 125,17-10]-3-dodecene ~3 8-Butyltetracyclo[4,4,0, C ~ ll o l2-5,17-l0]-3-dodecene 8-Ethylidenetetracyclo[4,4,0, ~= C H C 1-1~ 12-5,17-10]-3-dodecene 8-Ethylidene-9-methyltetracyclo I~LcllCII~ 14,4,0,12-5,17-10]-3-dodecene 2 5 Call 5 8-n-Propylidene-9-ethyltetracyclo ~CIICI12CI13 [4,4,0,l2-5,l7-10]-3-dodecene 1 7 2 ~ 3 Cll ( Cll " ) 2 8-Ethylidene-9-isopropyltetracyclo ¢~= C II C ll ,, [4,4,0,12 5,17- 10~ -3 -dodecene C~ 11 n 8-Ethylidene-9-butyltetracyclo (~-CIICII~ [4,4,0,12-5,17-10]-3-dodecene ~ 8-n-Propylidenetetracyclo ~=C~ICII2CIIJ
[4,4,0,12-5,17-10] -3 -dodecene Cll jl ~ 8-n-Propylidene-9-ethyltetracyclo ~CIICII2CIIJ [4,4,0,12-5,17-10]-3-dodecene ~C211 ~ 8-Ethylidene-9-ethyltetracyclo [4,4,0,12 5,17-10]-3-dodecene '.:
CII~C113)2 8-n-Propylidene-9-isopropyltetracyclo[4,4,0,12 5,17-10]-3- .'-' ~CIICI12CII j, --dodecene -~
, "; ~, ,,, " ", , , , " , ,, " ,, , ", ., ,;", ~, , j ,, ~: , ,;, : . , . , , . :
1 8 2 ~ 3 ~ ~
~C 111~ 8-n-Propylidene-9-butyltetracyclo CIICll 2CII a [4,4,0,12-5,17-10]-3-dodecene S[~=C-CII a 8-Isopropylidenetetracyclo Cll J [4,4,0,12-5,17-10]-3-dodecene C11"
~C-C11 ~ 8-Isopropylidene-9-methyltetracyclo 10C11, [4,4,0,l2 5,l7-10l-3-dodecene ~=C-C11 " 8-lsopropylidene-9-ethyltetracyclo Cll ~ [4,4,0,12-5,17-10]-3-dodecene C11(C113)2 8-Isopropylidene-9-~LC-CI1~ isopropyltetracyclo[4,4,0,12-5,17 l0]-3- ~ -C11~ dodecene [~3-C-CH ~ 8-Isopropylidene-9-butyltetracyclo :-[4,4,0,l2-5,l7 10]-3-dodecene ~11, Hexacyclo[6~6~1~l36~ll0 l3~o2.7~o9~l4]-4-heptadecene derivates such as:
l 9 [~ HeXaCYCIO[6~6~1~13~6~l~0~13 027 09141 ~) 4-heptadecene 5C 11~ 12-Methylhexacyclo[6,6,1,136, ¢~1 110 13,02 7,09 l4]-4-heptadecene C 2 1I r ~l 12-Ethylhexacyclo[6,6,1,13 6, ~ 110 13,02 7,09 14]-4-heptadecene -C IIJ
~C 1~ 2 C 1l 12-lsobutylhexacyclo[6~6~1~13~6~ , -'V~-VJ C 11 110 13,02 7,09-14]-4-heptadecene 1 5 ' '"' "
C IIJ C 11~ 1,6,10-Trimethyl-12-isobutyl- --¢~~C 112 C 1I hexacyclo[6,6,1,13 6,110 13 02 7 o9 14]-C H J C ~ C 1I J 4-heptadecene Octacyclol8,8,0,129,147,1,11 l8,113 l6,038,0l2-l7]-S-docosen derivates such as:
~ Octacyclo[8,8,0,l2.9,l4.7,l,ll.l8, ~ 113.I6~O3.8~OI2-I7]-5-dOCOSene 2a~
CllJ 15-Methyloctacyclo[8,8,0,12 9,14-7, (~1 1,11.18, 113 16,o3 8,0l2 l7~-S-docosene S 1~ C211~ 15-Ethyloctacyclo[8,8,0,12-9,14-7, ~/J~/,~/J~/J I 11.18, 1l3~l6~o3~8~ol2~l7]-s-docosene:
pentacyclo[6,6, 1,13-6,02-7,09-14] -4-hexadecene 10 derivates such as:
n~ Pentacyclol6~6~ 3~6~o2~7 09-14] 4 hexadecene C 11~ C 11~
~ ~ ~ 1,3-Dimethylpentacyclo[6,6,1, [ ~ ~J 13 6,02 7,09-l4]-4-hexadecene c 11 , 2 0 ~ 1 ,6-Dimethylpentacyclo[6,6, 1, ~/~ 13-6,02-7,09 l4]-4-hexadecene c 11 , 15 ,1 6-Dimethylpentacyclol6,6, 1, W/~J 136,02-7,09 l4]-4-hexadecene ,, . ,,, , .,,,, , ,, ",, ", - ." . , ,, - : , " .
2 ~J
heptacyclo-5-icosene derivates or heptacyclo-t-henicosene derivates such as:
~/~1/~ Heptacyclo[8,7,0,129,14 7,11l l7, 5 ~ ~`J 03 8 012 l6]-5-icosene 1~1'`1 Heptacyclo[8,8,0,12.9,l4.7,lll.l8, ~ 03 8,0l2 17] -S -henicosene ,.. . .
toricyclo[4,3,0,12 5]-3-decene derivatives such as:
I~J Tricyclo[4,3,0,12-5l-3-decene c }I , J~ 2-Methyl-tricyclo[4,3,0, 1 2-5]-3-decene ll)~
~ S-Methyl-tricyclo[4,3,0,12-s]-3-decene:
C 11 . . ' . .
-,' '-", . . . .....
tricyclo[4,4,0,12 5l-3-undecene derivatives such as:
¢~) Tricyclo~4,4,0,1~5]-3-undccene C 11, ~1~ 10-Methyl-tricyclo[4,4,0,12-s]-l~) 3-undecene:
pentacyclo[6,5,1,13 6, 02 7,09-13]-4-pentadecene derivatives such as:
Pentacyclo[6~s~ 3.6, ~V~ 02 7 09 l3]-4-pentadecene c 11. c 11.
1,3-Dimethylpentacyclo[6,5,1,13-6, - -l~V 02 7,09-l3]-4-pentadecene c 11 , ¢ 1~6-Dimethylpentacyclo[6,5,1,13 6, ~/~ 02-7,09-13]-4-pentadecene cll.
C 11. C 1-1-14,15-Dimethylpentacyclol6,5,1,13-6, ~J o2-7,og 13]-4-pentadecene:
7~
,, , , - , .. , " . , ; . , ., ,: ,. . . .. . .
3? ~ J
diene compounds such as:
~ Pentacyclol6,5,1,13-6, 1 02.7,09 13~-4,10-pentadecadiene:
Pentacyclo[7,4,0,12-5,08-l3,19-12]-3-pentadecene derivatives such as:
,'.
Pentacyclo[7~4~o~l2.s~o8.l3~ls.
pen tadecene CllJ
f ~ Methyl-substituted pentacyclo ~V [7,4,0,12 5,08-13,19-12]-3-pentadecene 20 heptacyclo[8,7,0,13 6,02-7,110 17, 011-16,112 l5]-4-icosene derivatives such as:
Heptacyclo[8,7,0,13-6,02-7,1l0.17~ .
~ 0 1 l-16, 1 l2-l5] -4-icosene ' ' " ' 3, C ~I J C 1~ J Dimethyl-substituted heptacyclo ~1~ [8,7,0,136,02.7,110.17,01l.l6,1l~l5]-4 ~ ~V icosene S nonacyclo[10,9,1,14-7,03-8,02.lo~ol2.2l~ 113.20,014.19,115.18] 5 pentacosene derivatives such as:
NonacyclollO,9,1,14.7,o3.8,o2.lo,ol2,2 ~V 1 l3.20,ol4.19,1 1s.l8]-5-pentacosene C 11 ~ C f 1 3 Trimethyl-substituted nonacyclo 1lo~9~l~l4 7~o3 8~o2 lo~ol2.2l~ll3.2 C ~1 ~ 0l4.l9, l 15.18] 5 -pentacosene " , , , ,, , ," ~ , ~, , ", , ", . , . s,,,, .. . , . , , . , ' ..
The following compounds can be mentioned as concrete examples of cycloolefins represented by the formula [I-bJ.
~ 5-Phenylbicyclo[2,2,1]hept -2-ene 0 ~ 5-Methyl-5-phenylbicyclo [2,2,1~ :
C H, hept-2-ene 15 ~ C H 2 ~ 5-Benzylbicyclo[2,2,1]hept-2-ene ~ 5-Tolybicyc1o[2,2,l]hept-2-ene ~ 1,4-Methano-l,la,4,4a- -tetrahydrofluorene , ' : ,,'',, , ;', ' ' ', " ~ ' ' ' '~' '''' 1,4-Methano-1,4,4a,5,10,10a-hexahydroanthracene Cyclopentadiene-acenaphthylene ~ addition products ~ S-(a-naphthyl)blcyclo[2,2,1]hept-:' ~
.
, 3,~
, The cycloolefin random copolymers (A) comprise ethylene units and the above-mentioned cycloolefin units a~
the essential components as aforesaid, however, if necessary, in addition to these two essential components, said copolymers may contain other copolymerizable unsaturated monomer components so long as they will not throw hinderances in the way of accomplishing the object of the present invention. The unsaturated monomers which ~ay be copolymerized, if necessary, with the copolymer~ (A) may include,for example, alpha-olefins having from 3 to 20 carbon atoms such as propylene, 1-butene, 4-methyl-1-. .
pentene, 1-hexene, 1-octene, l-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene which may be used in an amount of up to an equimolar to the ethylene component unit in the resulting random copolymer.
In the cycloolefin random copolymer ~A] having a . -softening point (TMA) of at least 70C, the recurr~ng units ~-la] derived from ethylene are present in an amount of from :
40 to 85 mol%, preferably from 50 to 75 mol%, while the .
recurring units lb] derived from the cycloolefin are present in an amount of from 15 to 60 mol%, preferably from ~
25 to 50 mol%, and these recurring units [a] and [b] are arranged at random in the substantially linear chain of the copolymer lA]. The molar percentage of the recurring units [a] and [b] were determined by 13C-NMR. The fact that this cycloole~in random copolymer ~A] is completely soluble in 2 ~3 decalin at 135C confirms that it is substantially linear and free from a gel-forming crosslinked structure.
The cycloolefin random copolymer [A] has an intrinsic viscosity [~] of from O.OS to 10 dl/g, preferably from 0.08 5 to 5 dl/g as measured in decalin at 135C.
The softening temperature (TMA) of the cycloolefin random copolymer [A] as measured by a thermal mechanical analyzer is at least 70C, preferably from 90 to 250C, and further preferably from 100 to 200C. The softening temperature ~TMA) referred to above was determined by monitoring thermal deformation behavior of a 1 mm sheet of the copolymer [A] using a thermomechanical analyzer manufactured and sold by Du Pont. More specifically, a quartz needle was vertically placed on the sheet under a load of 49 g and the assembly was heated at a rate of 5C/min, and a temperature at which the needle penetrated into the sheet by the depth of 0.635 mm was taken as TMA.
This cycloolefin random copolymer [A] has a glass transition temperature (Tg) of normally from 50 to 230C, preferably from 70 to 210C.
The crystallinity of this cycloolefin random copolymer lA] as measured by X-ray diffractometry is normally from 0 to 10%, preferably from 0 to 7~, and further preferably from 0 to 5%.
The cycloolefin copolymers (A) constituting the cycloolefin random copolymer composition used in the pre~ent invention for forming the substrate may all be -" ,;"",, .,,. , , ,~., , , , ' .. ,'': ' .:, ' , : ~' 2 ~
prepared by the processes proposed by the present inventors in Japanese Patent L-O-P Publns. Nos. 168708/1985, 120816/1986, 115912/1986 and 115916/1986, 252406/1987, 252407/1987, 271308/1986 and 272216/1986, while suitab~y S selecting the conditions.
Furthermore, in the present invention, there may also be used as the substrate material a cycloolefin random copolymer composition comprising a cycloolefin random copolymer [A] prepared by copolymerizing ethylene with a cycloolefin represented by the following formula [I~, [I-a or [I-b] and having an intrlnsic viscosity 1~] of 0.05-10 dl/g measured in decalin at 135C and a softening temperature (TMA) of at least 70C, and a cycloolefin random copolymer [B] prepared by copolymerizing ethylene lS with a cycloolefin represented by the formula lI~, [I-a] or lI-bl and having an intrinsic viscosity [~] of 0.05-5 dl/g measured in decalin at 135C and a softening temperature (TMA) of less than 70C.
Furthermore, the substrate of the magnetooptical recording media according to the invention may be made of polymers having recurring units of the general formula ~III] resulting from ring opening of the cycloolefin monomers [I], or polymers having recurring units of the general formula [IV] resulting from hydrogenation of the 25 units [III]. -. .
, -,,,: , , , , , , ,, ' ' ' " , ' '' ', ' ' , '' , ' ' ' ' ~, ,, . , ' , ' ' ' I I I I I
~ ' ' ~ IVI
In the general formula lIII] or lIV~, n and Rl to R12 nre as deflned ln the general formula IIl.
~ thlckness of the aubstrate, though not partlcul~rly llmlted, la preferably 0.5-5 mm and especlally l 2 mm.
In the lnventlon, matorlals for the recordlng layer 3 are not partlcularly llmlted to spe¢lflc ones. However, when therecording layer-3 used is a magnetooptical recording layer havlng a monoaxlal anosotropy perpendlcular to the layer surface, thls recordlng layer 3 la preferably composed of at least one member selected from amonq (1) 3d trans1tion metals and at least one element selected from among tl~i) rare earth elementa, or compoaed of at leaat one member selected from among ti) 3d tran~ltlon metals, tll) a corroalon-reslstant metal, and at least one element selected from smong (ill) rare earth elements.
~, 2 ~ 3~-~
The 3d transition metals used include Ee, Co, Ti, V, Cr, Mn, Ni, Cu and zn. Of these metals, preferred is Fe or Co, or are both of them.
The corrosion-resistant metal (ii) is capable of improving oxidation resistance of this magnetooptical recording layer as the recording layer 3 by incorporation into this recording layer 3 of said corrosion-resistant metal. Such corrosion-resistant metal used includes Pt, Pd, Ti, Zr, Ta, Mo, Nb and Hf. Of these metals, preferred 0 are Pt, Pd and Ti, and particularly Pt or Pd, or both of them.
The rate earth elements (iii) used lnclude, for example, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, La, Ce, Pr, Nd, Pm, Sm and Eu. Of these elements, preferred are Gd, Tb, Dy, Ho, Nd, Sm and Pr.
Such magnetooptical recording layer as mentioned above -desirably contains the 3d transition metal (i) in an amount of 30-85 atom%, preferably 40-70 atom%, the corrosion-resistant metal (ii) in an amount of less than 30 atom%, preferably 5-25 atom%, and the rare earth element (iii) in an amount of 5-50 atom~, preferab~y 25-45 atom%.
When the recording layer 3 used is other than the magnetooptical recording layer, for example, said recording layer is a phase change type recording layer, this recording layer 3 is composed of such an alloy film, for example, as consisting essentially of Te or Se, and of Te-Ge-Sb alloy fllm, In-Sb-Te alloy film Te-Ge-Cr alloy film "
,,' "' ,-', ' ' ' " ,. '`, ' ,' ,, ', ' ~ : ' , -, ., -" ,', ', , ,. ~ , , ", . . ....
,, . , , , : , .
.
,,, , , :, , .
.
or Te-Ge-Zn alloy fllm. Further an organlc dye fllm composed of polymethlne compounds or cyanlne compounds may al~o be used as the phase change type recording layer.
A thlcknes~ of the recordlng lnyer 3, though not partlcularly limited, is 50-5000 A, preferably 100-2000 A.
In the flr~t em~odiment o~ the present lnventlon, the metalllc layer ls formed from an alumlnum alloy contalnlng 0.1-10 atom~ of at least one element (metal) selected from among hafnlum and nioblum.
0 Concretely, the metalllc layer 4 19 composed of an alumlnum alloy contalnlng 0.1-10 atom%, preferably 1-6 atom% of hafnlum ~llf), an alumlnum alloy contalnlng 0.1-10 atom~, preferably 1-6 atom~ of nloblum (Nb), or of an alumlnum alloy contalnlng both hafnlum and nloblum ln an 5 amount totallng to O.l-10 atom~. -The metalllc layer 4 as mentloned above may contain small amounts of at least one of other metals ~elements) ln addltion to alumlnum, hafnlum and~or nloblum. Such other metal as mentloned above lnclude, ~or example, chromlum 20 ~Cr, only ln case of Al-Nb alloy), alllcon ~Sl), t~nt~lum ~-~Ta), copper ~Cu), tungston ~W)~ zlrconlum ~ZrJ, manganese ~Mn), magne~ium (Mg, only ln case of Al-Nb alloy) and vanadlum ~V). The amount of these other metals contalned, lf any, ln the metalllc layer 1~ usually less than 5 atom~, -preferably les~ than 2 atom~.
In the second embodiment . of the lnventlon, the metalllc layer is ~ormed from an alumlnum ,~', ' ' ' ~:
. 72932-67 .
alloy containlng 0.1~9.5 atom%, preferably 1-5 atom~ of hafnlum and 0.1-5 atom%, preferably 1-3 atom% of chromlum.
In thls aluminum alloy, the comblned content of haLnlum and chromium 1B preferably le~s than 10 atom~.
In the third embodiment of the lnventlon, the metalllc layer i9 formed from an aluminum alloy contalning 0.1-9.5 atom%, preferably 1-5 atom~ of hafnlum, 0.1-5 atom%, preferably 1-3 atom% of chromlum ~nd 0.1-9.5 atom~, preferably 1-5 atom~ of titanlum.
In this aluminum alloy, the combined content of hafnium, chromium and titanium 18 preferably les~ than 10 atom%.
The metallic layers of the 8econd and thlrd embodiments o~ the lnventlon as illu~trnted above may nl90 contain, in addition to the alumlnum, hafnium, chromium and tltanium, small amounts of a~ least one of other elements ~metals~. Such other elements (metal) lnclude, for example, silicon tSl),tantalum ~Ta), copper ~Cu), tungsten ~W), zirconlum ~Zr), manganese ~Mnl, and vanadlum ~V). The amount of these other elements (metals) contalned, if any, ln the metallic layer 1B
usually less than 5 atom%, preferably less than 2 atom~. -In the fourth embodiment of the invention, the metallic layer i~ formed from an aluminum alloy contalning 0.5-5 atom~, preferably 1-3 atom~ of hafnium, and 0.5-5 atom%, preferably 1-3 atom% of tltanlum.
,~ "
~ 72932-67 In thls alumlnum alloy, the comblned content of hafnium and t~tanlum 1~ 1-5.5 atom%, preferably 2-4 atom~.
The metalllc layer of the fourth embodiment of the lnvention as illustrated above may al90 contaln, in addition to aluminum, hafnlum and tltanlum, small amounts of at least one of other elements ~metals).
Such other elements ~metals) lnclude, for example, sillcon (Sl), tantalum ~Ta), copper ~Cu), tungsten (W), zlrconlum (Zr), manganese ~Mn), and vanadlum ~V). The amount of 0 these other elements ~metals) contained, if any, ln the metalllc layer is usually less than 5 atom~, prefer~bly less than 2 atom%.
In the flfth embodiment o~ tho invention, the metalllc layer is foxmed from an fllumlnum alloy contalning 0.1-10 atom%, preferably 1-5 atom% of hafnlum and 0.1-10 atom%, preferably 1-5 atom~ o~ -magnesium.
In this aluminum alloy, the comblned content of - -hafnlum and magnesium i~ le~s than 15 atom%, preferably 1- ~ -10 atom%.
In the sixth . embodiment -of the lnventlon, the metallic layer 13 formed from an aluminum alloy contalning 0.1-10 atom%, preferably 1-5 atom% of ~ -hafnium, 0.1-10 atom%, preferably 1-5 atom~ of magneslum and 0.1-10 atom~, preferably 1-5 atom% of tltanium.
A
. . .
In thls alumlnum alloy, the comblned content of hafnium, magne~lum and tltanlum 18 deslrably leas than 15 atom%, preferably l-lO atom%.
In the ~eventh embodiment of the lnventlon, the metalllc layor is formed from an alumlnum alloy contalnlng 0.1-10 atomt, preferably 1-5 atom~ of hafnlum, 0.1-10 atom%, preferably 1-5 atom% of magneslum and not more th~n 10 atomt, pre~erably O.l-10 atom~, more preferably 1-5 atom~ of chromlum.
0 In thl~ alumlnum alloy, the combined content of hafnium, maqneslum and chromlum la deslrably les~ than 15 atom%, preferably 1-10 atom~.
In the elghth embodiment of the lnventlon, the metalllc layer 19 formed from an aluminum t5 alloy containlng O.l-10 atom%, preferably 1-5 atom% of hafnlum, O.l-lO atom~, pre~erably 1-5 atom~ of m~gneslum, lesa than 10 atom%, preferably 1-5 atom% of chromlum and O.l-10 atom%, preferably 1-5 atom% of tltanlum.
In this alumlnum alloy, the combined content of hafnium, magnesium, chromlum and titanlum 1~ deslrably lesJ
than 15 atom%, preferably l-lO atom%.
In the flfth, slxth, seventh and elghth embodiments of the lnventlon a9 lllu~trated above, the metallic layers may each contaln small amounts of at least one of other elements ~metals) ln additlon to hafnlum, mAgnesium, titanlum and chromlum. Such ~mall amounts of other elements ~metals) include, for example, sil~con ~Sl), ., , : , .... .
i , , ,, , ,, .",. :: , , , ,, ~ , ... .. . . . . ............. . . .
' '''~ ' ' ~'''` ' '' '', ,' "' ',' ' :
" .~ , ~
. .
.
tantalum (Ta), copper (Cu), tungsten (w), zirconium ~Zr), manganese (Mn) and vanadium ~v). The amount of such other elements (metals) contained, if any, in the metallic layer is usually less than 5 atom%, preferably less than 2 atom%
A thickness of the above-mentioned metallic layers i8 100-5000 A, preferably 500-3000 A and especially 700-2000 A.
The metallic layers used in the present invention fulfil their function as good heat conductive layers, and 0 in the presence of these metallic layers, the center portion of pits formed in the recording layers may be prevented from being excessively heated to high temperature -by the action of the recording laser beam applied thereto.
As the result, it is con~idered that the dependence of the information recording media of the invention on linear velocity is made small.
The metallic layers of the invention which are also excellent in corrosion resistance have such a characteristic feature that the dependence of the information recording media on linear velocity is small even after being used for a long period of time, and that said metallic layers are excellent in performance of protecting the recording layers.
The structure of the information recording media of the invention shown in Fig. 1 is given by way of illustration but not of limitation. For instance, they may -~
be prepared by providing a protecting film (enhancing film) -' 5 on the aforementloned substrate 2 and then provlding further the recordlng layer 3 and the metalllc l~yer 4 ln that order. The protectlve film (enhanclng film) 5 ls formed desirably from Si3N4, SiNX ~O<x~4/3), AlN, ZnSe, znS, Sl or CdS, though not llmlted thereto. A thickness of this protective film is loo-aooo A, preferably about 300-1500 A. Of these materials used for formlnq the protectlve fllm, particularly preferred are Si3N4 and SiNX ~O<x<4/3) from a viewpolnt of crack reslstance.
0 The functlon of the protectlve fllm 19 to protect the recording l~yer and, at the same tlme, lt enhances the lnformatlon recordlng medium in sensltlvlty and functlons as an enhanclng fllm. Such a protective layer deslrably has a refractlve lndex larger than that of the substrate.
I5 The lnformatlon recordlng medla of the present lnventlon may be prepared by formlng on the substrate the recordlng layer and the metalllc layer and, lf necessary, the protectlve layer uslng such fllm-formlng methods, for example, vacuum depos~tlon, sputterlng, electron beam depo~ltion or the llke.
The lnformatlon recordlng medla of the present lnvent~on comprlslng the metalllc lnyer compoaed of a 2S speclflc aluminum alloy are excellent ln corroslon reslJtance, small ln the dependence of the recordlng power ,, , ,: ', -.. . . .. . .
38 2 ~
on linear velocity and in performance of protecting therecording layer.
The present invention is illustrated below with reference to examples, but it should be construed that the invention is in no way limited to those examples.
The term "optimum recording power" used in the following Examples designates a recording power with which writing signals at a frequency of 1 MHz and a duty factor of SO% are recorded and which makes mlnimum the secondary harmonics of signals reproduced from the recorded signals.
Recording media show a lower degree of dependence on the linear velocity when the information recording media show smaller difference of the optimum recording powers determined at different linear velocities.
1 5 ~m~.
Hereinafter, corrosion resistance of the metallic layer was examined first by the following procedure.
On a glass substrate, a metallic layer composed of an aluminum-hafnium alloy was deposited to a thickness of 700 2 0 A by the sputtering process using an aluminum-hafnium --~
composite target. The hafnium content in the above- --mentioned aluminum-hafnium alloy (layer) constituting the metallic layer as formed was 4 atom% and the alumium content was 96 atom%.
This metallic layer as formed was immersed for 4 hours at 60C in an aqueous solution containing 10% by weight of 80dium chloride, whereby the corrosion re8istance of the '"" "'""'" ' '' ', ' ' ' " " ~' '' ' ' , '' '''' -',,: ' ''' ' ' ~ '''', "" "' ' ', ',,. ' i' 2 ~
metallic layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the sodium chloride aqueous solution of said metallic layer.
Example 2 On a glass substrate, a metallic layer composed of an aluminum-niobium alloy was deposited to a thickness of 700 A by the sputtering process using an aluminum-niobium composite target. The niobium content in the aluminum-niobium alloy (layer) constituting the metallic layer as formed was 4 atom%.
This metallic layer was immersed four hours at 60C in an aqueous solution containing 10% by weight of sodium chloride, whereby the corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change -before and after the immersion in the sodium chloride aqueous solution of said metallic layer.
Comparative Example 1 On a glass substrate, a metallic layer composed of aluminum was deposited to a thickness of 700 A by the sputtering process using an aluminum target.
This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containlng 10% by weight of sodium chloride, whereby corrosion resistance of the metallic , " ', ,,,, ", , ",. . . . . .
, , , ,, , : , , - , :
layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer measured after the immersion in the aqueous sodium chloride solution of said metallic layer was lower by about 30% than that measured before said immersion.
E~m~
On a disk substrate composed of an amorphous copolymer of ethylene with l,4,5,8-dlmethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene ~structure formula:abbreviated to DMON hereinafter), the amorphou~ copolymer having 59 mol% of an ethylene unit content determined by NMR analysis, an intrinsic viscosity ~ of 0.42 dl/g measured in decalin at 135C and a softening temperature (TMA) of 159C~ were deposited successively a protective film composed of Si3N4 to a thickness of 1100 A and a recording layer composed of PtloTb2gFessCo6 to a thickness of 260A by the sputter$ng process, and thereon was deposited a metallic layer composed of an aluminum-hafnium alloy to a thickness of 700 A by the sputtering process u-Qing an aluminum-hafnium composite target. The hafnium content in the aluminum-hafnium alloy (layer) constituting the metallic layer was 4 atom% and the aluminum content was 96 atom%.
The information recording medium thus obtained was held for about 720 hours under the circumstanceQ of 80C
and a relative humidity of 85%, whereby corrosion J
resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said metallic layer under the circumstance of 80C and a relative humidity of 85%.
This fact means that the metallic layer are excellent in corrosion resistance and in performance of protecting the recording layer.
Example 4 Example 3 was repeated except that the metallic layer formed had a thickness of 500 A.
The information recording medium obtained was held for about 720 hours under the circumstances of 80C and a relative humidity of 85% to measure reflectance of said information recording medium, whereby the reflectance of said information recording medium did not change.
The optimum recording power of this information recording medium at a linear velocity of 5.7 m/sec was 3.7 mW, and the optimum recording power at a linear velocity of 11.3 m/sec was 5.2 mW.
Comparative Example 2 On a substrate used in the Example 3, were deposited successively a protective film composed of Si3N4 and a recording layer composed of Pt1oTb2gFessCo6 by the ... . . . . . . . . ....................... .. .
' ', , ,: , ,, , :.................... , ., .. : .
,, ., , , -, . . . .......................... . .
;:: . , ~. , ~ 7 sputtering process, and thereon was deposited a metallic layer composed of aluminum to a thickness of 700 A by the sputtering process using an aluminum target.
The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated ~ ~ r ro ~t~`o r~
l~ by measuring a change in reflectance of ~aid mctallic rCC~r d"~ 'j ~d, ~ .
1 0 lc~yt ~
The reflectance of said information recording medium measured after holding said recording medium was lower by about 15% than that measured before said holding.
~x~mple 5 Hereinafter, corrosion resistance of a metallic layer composed of an aluminum-hafnium-chromium alloy was examined by the followlng procedure.
On a glass substrate, was deposited a metallic layer composed of an aluminum-hafnium-chromium alloy to a -thickness of 1000 A by the sputtering process using an aluminum-chromium-hafnium composite target.
The hafnium and chromium contents of the metallic ' -layer thus formed were each 2 atom%.
This metallic layer was immersed for 4 hours at 60C
ln an aqueous solution containing 10~ by weight of sodium chloride, whereby corrosion resistance of the metallic " ,, .,",".,~ .,,, ' . . " ', . ,,,' ~,r~S ~ , ;J
layer was evaluated by measuring a change in reflectance of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer.
The number of pinholes observed in the metallic layer after the above-mentioned immersion was less than 50 pieces ~49 pieces) per unit surface area (5 cm x 5 cm).
Example 6 On a substrate used in the Example 3, were deposited successively a protective film (1100 A in thickneqs) composed of Si3N4 and a recording layer (260 A in thickness) composed of Pt1oTb2gFessCo6 by the sputtering process, and thereon was deposited a metallic layer (500 A
in thickness) composed of an Al-Cr-Hf alloy by the sputtering process using a composite target of Al-Cr-Hf.
The Cr and Hf contents in the Al alloy (layer) constituting the metallic layer obtained were each 2 atom%.
The information recording medium obtained was held for -about 720 hours under the circumstances of 80C and a relative humidity of 85%, whereby'corrosion resistance of the metallic layer and proLective function of the metallic layer for the recording layer were evaluated by measuring a ~J change in reflectance of the metallic layer and surface profile of the metallic layer.
, , , , , ~ ' , , ':, .' ' , , , ' ', , , , . . . . . . .. .
'~", ,''''''' .,''' '' ~'' ' ','' ,' "',','.,', '' ,, s 1, ~3 ~ ~
r rn~,t~ l~ n ~ ~ c, ~ r d ~ r>7 ~ ~
The reflectance of the metalllc layer did not change before and after holding the same under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information recording medium at a linear velocity of (5.7) m/sec was (3.6) mW, and the optimum recording power at a linear velocity of (11.3) m/sec was (5.3) mW.
On a substrate used in the Example 3, were deposited successively a protective film (1000 A in thickness) composed of Si3N4 and a recording layer (500 A in thickness) composed of PtloTb2gFessco6 by the sputtering process, and thereon was deposited a metallic layer (700 A
in thickness) composed of an Al-Cr-Hf alloy by the sputtering process using a composite target of Al-Cr-Hf.
The Cr and Hf contents in the Al alloy (layer) constituting ~ -the metallic layer obtained were each 2 atom%.
The information recording medium obtained was held for about 720 hours under the circumstances of 80C and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer for the recording layer were evaluated by measuring a ) r ~ r~ r lz c c~r d, ~ 7 ~ e~
change in reflectance of the mctallic laycr and su~face profile of the metallic layer.
o r rn Q~ o n r e c ~ ~ J. r~ ~ ~ ~d The reflectance of the metallic l~ycr did not change before and after holding the same under the circumstances of 80C and a relative humidity of 85%.
" :. "
,~, . ,, ", . .. ..
.
Comparative Example 3 On a glass substrate, a metallic layer composed of an aluminum-chromium alloy was formed to a thicknes~ of 1000 A
by the sputtering process using an aluminum-chromium S composite target.
The chromium content of the metallic layer thus formed was 2 atom%.
This metallic layer was immersed for 9 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride.
After the 4-hour immersion, changes in reflectance and surface profile of the metallic layer were measured. The reflectance of the metallic layer thus measured decreased by about 2%.
The number of pinholes ob~erved on the metallic layer was about 70 pieces per unit film surface area (5 cm x 5 cm).
Comparative Example 4 A metallic layer containing 4 atom~ of chromium was obtained in the same manner as in Comparative Example 3 but using a compo~ite target of an al~minum-chromium alloy --different in composition from the composite target used in Comparative Example 3.
- This metallic layer was immersed in an aqueous sodium chloride solution in the same way as in Comparatlve Example 3 to measure changes in reflectance and surface profile of the metallic layer after the immersion thereof.
, i . , : , . ....................... .
,, , , , , , , ~,, ~, , ., ~ , ... . .
~ r~ h~
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer after the immersion S thereof was about 70 pieces per unit film surface area (5 cm x 5 cm).
Example 8 Hereinafter, corrosion resistance of the metallic layers composed of an aluminum-hafnium-titanium alloy was .
examined.
On a glass substrate, a metallic layer composed of an aluminum-hafnium-titanium alloy was formed by the sputtering process using a composite target of aluminum(Al)-hafnium(Hf)-titanium (Ti).
lS The titanium content of the metallic layer thus obtained was 1 atom%, and the hafnium content thereof was 2 atom%.
~ ,, ~ ,, This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride, whereby corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of -.
said metallic layer and surface profile of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer after the immersion -" ''.~",; '"',~''" "' ,' '" "",'"'',",' " ", ''','~'' ".' ' : ' ,: , , , ,, i .,, , ,"
thereof was less than 40 pieces (38 pieces) per unit film surface area t5 cm x 5 cm).
Example 9 A metallic layer containing 2 atom% of titanium and 1 atom% of hafnium was obtained in the same manner as in Example 8 but using a composite target composed of an aluminum-titanium-hafnium alloy different in composition from the composite target used in Example 8.
This metallic layer was immersed in the same manner as in Example 7 in the aqueous sodium chloride solution to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of the metallic layer after the immersion thereof.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of sald metallic layer, and the number of pinholes observed in the metallic layer after the immersion -was less than 40 pieces (33 pieces) per unit film surface area (5 cm x 5 cm). -, Example 10 On a substrate used in the Example 3, were deposited . , successively a protective film (1100 A in thickness) composed of Si3N4 and a recording layer ~260 A in thickne,~s) composed of Pt1oTb2gFessCo6 by the sputtering process, and thereon was deposited a metallic layer (500 A
/, f~ J COh~ 'fo~ f cor~ QJrO~ T,' ln thickness) composed of an Al-Hf-Ti alloy\by the ' ~
sputtering process using a composite target of Al-Hf-Ti. ~)~y ,' ' ' '"'"''-", :', " "' ' '" '' ' . ',,,,"', ~,, ;;, ;. , ':
: . , . ,, , , :
!5 The information recording medium thus obtained wa~
held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whereby corrosion resistance of the metallic layer and protective function of the metallic layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said recording medium under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information --recording medium at a linear velocity of (5.7) m/sec was (3.3) mW, and the optimum recording power at a linear velocity of (11.3) m/sec was (4.7) mW.
Comparative Example 5 A metallic layer containing 2 atom% of titanium was obtained in the same manner as in Example 8 but using a composite target of aluminum-titanium in place of aluminum-titanium-hafnium used in Example 8.
This metallic layer was immersed in the aqueous sodium chloride solution in the same way'as in Example 8 to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of sald metallic layer after the immersion thereof.
The reflectance of the metallic layer decreased by about 8% by the immersion of said metallic layer.
,. . , , . ,-., . . . ,.. , ~, . . . . .
,, ,, ,, . . i ,, - : . ',',...... ........... " ,' , .
, ,, , , , , , ' :'' ' ' ' ' ' .
2 ~
The number of pinholes observed in the metallic layer was 51 pieces per unit film surface area (5 cm x 5 cm).
Comparative Example 6 A metallic layer composed of an aluminum-titanium alloy containing 4 atom% of titanium was formed in the same manner as in Comparative Example 5.
This metallic layer was immersed in the same way as in Example 8 in the aqueous sodium chloride solution to evaluate corrosion resistance of the metallic layer by measuring changes in reflectance and surface profile of said metallic layer after the immersion thereof.
The reflectance of the metallic layer decreased by about 2% by the immersion of said metallic layer, The number of pinholes observed in the metallic layer was more than 115 pieces per unit film surface area (5 cm x 5 cm)-ExamDle 11 On a substrate used in the Example 3, were deposited successively a protective film (1000 A in thickness) composed of Si3N4 and a recording layer (500 A in thlckness) composed of PtloTb2gFe55Co6 by the sputtering - -proce~s, and thereon was deposited a metallic layer (700 A
z~ (A cO,"~ JD~ /~ Hf COht~r>t ~ oto~7~o/ T~c~ t~ ~
D in thickne~-c) composed of an Al-Hf-Ti alloy\by the - :
sputtering process using a composite target of Al-Hf-Ti. --The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%, whèreby corrosion '"'''',''' ''"'"''',''', ,'''' 'i','""','''", '''''''.',"';, ;'"' .~'.' ~'':
2 ~
so resistance of the metallic layer and protective function of the metallic layer were evaluated by measuring a change in reflectance of said information recording medium.
The reflectance of the information recording medium did not change before and after holding said recording medium under the circumstances of 80C and a relative humidity of 85%.
m~le 12 On a glass substrate, a metallic layer ~1000 A in .
thickness) composed of an aluminum-hafnium-magnesium alloy was formed by the sputtering process using a composite target of aluminum (Al)-hafnium (Hf)-magnesium (Mg).
This metallic layer was immersed for 4 hours at 60C
in an aqueous solution containing 10% by weight of sodium chloride, whereby corrosion resistance of the metallic layer was evaluated by measuring a change in reflectance of said metallic layer and surface profile of said metallic layer.
The reflectance of the metallic layer did not change before and after the immersion in the aqueous sodium chloride solution of said metallic layer, and the number of pinholes observed in the metallic layer was less than 30 pieces (25 pieces) per unit film surface area (5 cm x 5 cm).
~x~m~ 13-14 Metallic layers were formed in the same manner as in Example 12 but using composite targets as shown in Table 1.
,,,. . , , , ,, - . ; ~ , - . ,:,, ' '.,, . .",.~ . .. ~,.,: ' . .' `' .' ;' . : . ., . . - . . .
'., ' ., ' ,.' ; ,' : . '," ':' .' . , . ; ,:. ,, ,, . ' . . ',, ', , - .
,. ~ , ,, ., : ., s~
The atom content and the number of plnholes of the metallic layers thus formed are shown in Table 1.
' ' ,' ',''' i' ' ,, ,',''~ " ''' ', ' , ,: , ,' , ,, ,; , :, ,, ,,, ' ,, . ~ :: ,....... .
2 ~
Table 1 Composite target usedAtom content and (at%) Composition Number of of Metallic Mg Hf Ti pinholes not more Example 12 Al-Mg-Hf 4 4 - than 30 pieces (25 pieces) , not more Example 13 Al-Mg-Hf 4 2 - than 30 pieces (30 Pieces) .-. _ Less than Example 14 Al-Mg-Hf-Ti 4 2 1 30 pieces . (30 pieces) Comparative Example 7 Al-Mg 5 - _ 70 pieces .xample 15 On a substrate used in Example 3, were deposited successively a protective film (1100 A in thickness) composed of Si3N4, and a recording layer (260 A in thickness) composed of PtloTb2gFèssco6~ by the sputtering process, and was deposited thereon a metallic layer (500 A
in thickness) composed of an Al-Mg-Hf alloy by the sputterlng process using a composite target of aluminum (Al)-hafnlum (Hf)-magnesium (Mg). The Mg content was 4 "..
2 ~
atom% and the Hf content was 2 atom% in the Al alloy (layer) constituting the metalllc layer as formed above.
The information recording medium thus obtained was held for about 720 hours under the circumstances of 80C
and a relative humidity of 85%.
The reflectance of the information recording medium did not change before and after holding the information recording medium under the circumstances of 80C and a relative humidity of 85%.
The optimum recording power of this information recording medium at a linear velocity of ~5.7) m/sec was ~4.0) mW, and the optimum recordlng power at a linear velocity of ~11.3) m/sec was ~5.6) mW.
Comparative Examplc 7 On a glass substrate, was formed a metallic layer ~looo A in thickness) composed of an aluminum-magnesium alloy by the sputterlng process using a composite target of aluminum-magnesium.
The magnesium content in the metallic layer thus obtained was 5 atom%.
This metallic layer was immersed for 4 hours at 60C ~-in an aqueous solution containing 10% by weight of sodium chloride.
The reflectance of the metallic layer immersed 25 decreased by about 2% by the above-mentioned immersion. -.. .
, ~ , , .
2 ~
The number of pinholes observed in the metallic layer was about 70 pieces per unit film surface area (5 cm x 5 cm).
Claims (20)
1. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of at least one element selected from the group consisting of hafnium and niobium based on all atoms constituting the aluminum alloy.
2. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium and 0.1-5 atom% of chromium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and chronium being less than 10 atom%.
3. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium, 0.1-5 atom% of chromium and 0.1-9.5 atom% of titanium based on all atoms constituting the aluminum alloy, the combined content of the hafnium, chromium and titanium being less than 10 atom%.
4. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.5-5 atom% of hafnium and 0.5-5 atom% of titanium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and titanium being 1-5.5 atom%.
5. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium and 0.1-10 atom% of magnesium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and magnesium being less than 15 atom%.
6. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and 0.1-10 atom% of titanium based on all atoms constituting aluminum alloy, the combined content of the hafnium, magnesium and titanium being less than 15 atom%.
7. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and not more than 10 atom% of chromium based on all atoms constituting the aluminum alloy, the combined content of the hafnium, magnesium and chromium being less than 15 atom%.
8. An information recording medium having a substrate and thereon a recording layer and a metallic layer, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and 0.1-10 atom% of titanium and less than 10 atom% of chromium based an all atoms constituting aluminum alloy, the combined content of the hafnium, magnesium, titanium and chromium being less than 15 atom%.
9. The information recording medium as claimed in any of claims 1-8 wherein the recording layer is a magnetooptical recording layer.
10. The information recording layer as claimed in any of claims 1-8 wherein the metallic layer has a film thickness of 100-5000 A.
11. An information recording medium which comprises:
a substrate, a metallic layer, and a recording layer between the substrate and the metallic layer, wherein the said information recording medium may also comprise a protective layer between the substrate and the record-ing layer and the metallic layer is composed of an aluminum alloy having the following composition:
(i) from 0.1 to 10 atom% of at least one element selected from the group consisting of hafnium and niobium;
(ii) from 0 to not more than 10 atom% of chromium;
(iii) from 0 to 10 atom% of titanium;
(iv) from 0 to 10 atom% of magnesium; and (v) the remainder being essentially aluminum and impurities including silicon, tantalum, copper, tungsten, zirconium, manganese, magnesium and vanadium;
the total content of the elements (i) through (iv) being less than 15 atom% when magnesium is included or being less than 10 atom% when magnesium is not included; and the total content of the impurities being less than 5 atom%, all based on the aluminum alloy.
a substrate, a metallic layer, and a recording layer between the substrate and the metallic layer, wherein the said information recording medium may also comprise a protective layer between the substrate and the record-ing layer and the metallic layer is composed of an aluminum alloy having the following composition:
(i) from 0.1 to 10 atom% of at least one element selected from the group consisting of hafnium and niobium;
(ii) from 0 to not more than 10 atom% of chromium;
(iii) from 0 to 10 atom% of titanium;
(iv) from 0 to 10 atom% of magnesium; and (v) the remainder being essentially aluminum and impurities including silicon, tantalum, copper, tungsten, zirconium, manganese, magnesium and vanadium;
the total content of the elements (i) through (iv) being less than 15 atom% when magnesium is included or being less than 10 atom% when magnesium is not included; and the total content of the impurities being less than 5 atom%, all based on the aluminum alloy.
12. A magnetooptical information recording medium which comprises:
a transparent substrate, a metallic layer, and a magnetooptical recording layer between the substrate and the metallic layer, wherein [A] the said information recording medium may also comprise a protective layer between the substrate and the recording layer, [B] the magnetooptical recording layer has a monoaxial anisotropy perpendicular to the layer surface and contains (i) a 3d transition metal in an amount of 30 to 85 atom%, (ii) a corrosion-resistant metal in an amount of less than 30 atom% and (iii) a rare earth element in an amount of 5 to 50 atom%, and [C] the metallic layer is composed of an aluminum alloy having the following composition:
(i) from 0.1 to 10 atom% of at least one element selected from the group consisting of hafnium and niobium;
(ii) from o to not more than 10 atom% of chromium;
(iii) from 0 to 10 atom% of titanium;
(iv) from o to 10 atom% of magnesium; and (v) the remainder being essentially aluminum and impurities including silicon, tantalum, copper, tungsten, zirconium, manganese, magnesium and vanadium;
the total content of the elements (i) through (iv) being less than 15 atom% when magnesium is included or being less than 10 atom% when magnesium is not included; and the total content of the impurities being less than 5 atom%, all based on the aluminum alloy.
a transparent substrate, a metallic layer, and a magnetooptical recording layer between the substrate and the metallic layer, wherein [A] the said information recording medium may also comprise a protective layer between the substrate and the recording layer, [B] the magnetooptical recording layer has a monoaxial anisotropy perpendicular to the layer surface and contains (i) a 3d transition metal in an amount of 30 to 85 atom%, (ii) a corrosion-resistant metal in an amount of less than 30 atom% and (iii) a rare earth element in an amount of 5 to 50 atom%, and [C] the metallic layer is composed of an aluminum alloy having the following composition:
(i) from 0.1 to 10 atom% of at least one element selected from the group consisting of hafnium and niobium;
(ii) from o to not more than 10 atom% of chromium;
(iii) from 0 to 10 atom% of titanium;
(iv) from o to 10 atom% of magnesium; and (v) the remainder being essentially aluminum and impurities including silicon, tantalum, copper, tungsten, zirconium, manganese, magnesium and vanadium;
the total content of the elements (i) through (iv) being less than 15 atom% when magnesium is included or being less than 10 atom% when magnesium is not included; and the total content of the impurities being less than 5 atom%, all based on the aluminum alloy.
13. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of at least one element selected from the group consisting of hafnium and niobium based on all atoms constituting the aluminum alloy.
14. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium and 0.1-5 atom% of chromium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and chromium being less than 10 atom%.
15. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-9.5 atom% of hafnium, 0.1-5 atom% of chromium and 0.1-9.5 atoms% of titanium based on all atoms constituting the aluminum alloy, the combined content of the hafnium, chromium and titanium being less than 10 atom%.
16. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.5-5 atom% of hafnium and 0.5-5 atom% of titanium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and titanium being 1-5.5 atom%.
17. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium and 0.1-10 atom% of magnesium based on all atoms constituting the aluminum alloy, the combined content of the hafnium and magnesium being less than 15 atom%.
18. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and 0.1-10 atom% of titanium based on all atoms constituting aluminum alloy, the combined content of the hafnium, magnesium and titanium being less than 15 atom%.
19. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and not more than 10 atom% of chromium based on all atoms constituting the aluminum alloy, the combined content of the hafnium, magnesium and chromium being less than 15 atom%.
20. The information recording medium according to claim 12, wherein the metallic layer is composed of an aluminum alloy containing 0.1-10 atom% of hafnium, 0.1-10 atom% of magnesium and 0.1-10 atom% of titanium and less than 10 atom% of chromium based on all atoms constituting aluminum alloy, the combined content of the hafnium, magnesium, titanium and chromium being less than 15 atom%.
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP97206/1989 | 1989-04-17 | ||
| JP9720689 | 1989-04-17 | ||
| JP1127532A JPH0214482A (en) | 1989-05-19 | 1989-05-19 | Disk cartridge |
| JP129553/1989 | 1989-05-23 | ||
| JP12955389 | 1989-05-23 | ||
| JP129554/1989 | 1989-05-23 | ||
| JP12955489 | 1989-05-23 | ||
| JP157532/1989 | 1989-06-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2014355A1 true CA2014355A1 (en) | 1990-10-17 |
Family
ID=27468520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2014355 Abandoned CA2014355A1 (en) | 1989-04-17 | 1990-04-11 | Information recording media |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2014355A1 (en) |
-
1990
- 1990-04-11 CA CA 2014355 patent/CA2014355A1/en not_active Abandoned
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |