JPH0441057B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical recording media, particularly heat mode optical recording media. Prior Art Optical recording media have the characteristic that the recording medium does not deteriorate due to wear since the medium and the writing or reading head are not in contact with each other, and for this reason, research and development of various optical recording media are being carried out. Among such optical recording media, heat mode optical recording media are being actively developed because they do not require image processing in a darkroom. This heat mode optical recording medium is an optical recording medium that uses recording light as heat. One example is a heat mode optical recording medium that uses recording light such as a laser to melt or remove a part of the medium, which is called a pit. There are some devices that perform writing by forming small holes, record information using the pits, and perform reading by detecting the pits with a readout light. One example of such a pit-forming type medium is one in which a recording layer made of a light-absorbing dye is formed on a substrate and the dye melts to form pits, and one in which a recording layer made of a light-absorbing dye is formed on a substrate to form pits. A recording layer containing a resin and a light-absorbing dye is formed, and a recording layer that forms pits by decomposing nitrocellulose, etc., or a recording layer consisting of a thermoplastic resin and a light-absorbing dye is coated, and the resin and the dye are coated. Some are known that melt to form pits. However, in such media, by preservation,
The dye migrates and mixes into the substrate, re-agglomerates, recrystallizes, or bleeds out, resulting in disadvantages such as a decrease in writing sensitivity and a decrease in read S/N ratio. especially,
The readout S/N ratio decreases significantly due to high temperature storage after recording. Purpose of the Invention The present invention was made in view of the above circumstances, and its main purpose is to provide an optical recording medium with improved storage stability, especially storage stability at high temperatures after recording. . These objects are achieved by the invention described below. That is, the first invention is an optical recording medium characterized by having a recording layer made of a dye polymer or a composition thereof on a substrate. Furthermore, a second invention is an optical recording medium characterized by having a recording layer on a substrate, which is made of a dye polymer or a composition thereof, and further has a quencher added thereto. Specific Configuration of the Invention The specific configuration of the present invention will be described in detail below. The recording layer in the present invention is made of a dye polymer or a composition thereof. In this case, the dye polymer refers to a dye polymer having two or more molecules of one or more types of dye, or a copolymer of the dye and other components. Among these dye polymers,
One or more homocondensates or co-condensates of dyes having one or more functional groups, or one or more dyes having one or more functional groups; Preferably, it is a co-condensate with one or more co-condensate components having one or more functional groups. The condensation reaction for forming such a condensate is preferably one or a combination of two or more of the following condensation reactions involving functional groups. That is, the dye condensate in the present invention is
Two or more molecules of one or more types of dyes can be connected via one or more types of linking groups obtained by the following reactions, or via the following linking groups and co-condensation component residues described below. Preferably, it is a polymerized one. In the following, A represents a dye or a residue of a co-condensed component, R represents hydrogen or a substituted or unsubstituted alkyl group or aryl group, and X represents a halogen. (1) −COOH＋−OH→−COO−＋H ₂ O↑ (2) −COOH＋−NHR→−CONHR−＋H ₂ O↑ (7) −COCl＋−OH→−COO−＋H ₂ O↑ (8) −COCl＋−NH ₂ →−CONH＋H ₂ O↑ (11) −OH+−NCO→−OCONH− (12) −NH ₂ +−NCO→−NHCONH− (14) −NH ₂ +SO ₃ H→−SO ₂ NH−＋H ₂ O↑ (18) −SO ₃ H＋−OH→−SO ₃ −＋H ₂ O↑ (19) −SO ₂ Cl＋−OH→−SO ₃ −＋HCl↑ (20) −SO ₂ Cl＋NH ₂ →−SO ₂ NH−＋HCl↑ (23) −CHO+−NH ₂ →−C=N−+H ₂ O↑ (24) −OCOCl+−NH ₂ →−OCONH−+HCl↑ (25) 2−NHCO ₂ OH＋H ₂ NCONH ₂ →−NHCH ₂ NHCHNHCH ₂ NH − (26) −CONHNH ₂ +−COCl →−CONHNHCO− ₍ 28 ₎
It is preferable that it has one or more of the functional groups listed in (1) to (28). In this case, in particular, the above (1), (2), (3), (5), (6),
(7), (8), (9), (11), (12), (13), (14), (1
9),
(20) is preferred. In particular, the functional groups of the dyes and cocondensation components used are -OH, _-NH2 , -COOH, -
COCl, −NCO,

[Formula] One or more of -SO ₂ Cl, an acid anhydride group, and -SO ₃ H, and particularly the functional group of the dye is preferably -OH, -NH ₂ , -COOH, and -COCl. Note that two or more types of functional groups may be added to the dye and the cocondensation component, but considering problems in their synthesis and ease of control of the condensation reaction,
It is preferable that the dye and cocondensation component have one type of functional group, and in particular, the dye has about 2 to 4 functional groups, and the cocondensation component has 2 to 3 functional groups, especially 2 functional groups, respectively.
Preferably, it is sensual. In particular, it is preferable to use difunctional compounds, since a linear polymer can be obtained and the thermoplasticity will be good. Then, two types of bifunctional dyes are usually used in a combination that causes the condensation reactions of (1) to (28) above, or
It is preferable to use a bifunctional dye and a bifunctional co-condensation component. As the dye to be used, the following are suitable. D1 Cyanine dye 2-thiazolyl, 2-(4,5-benzothiazolyl), 2-[naphtho(1,2-d)thiazolyl], 2-[naphtho(3,4-d)thiazylyl],
2-[phenanthrino(9,10-d)thiazolyl], 2-henzoxazolyl, 2-selenazolyl, 2-quinolyl, 4-quinolyl, 2-benzimidazolyl and other heterocyclic residues at both ends; , respectively substituted or unsubstituted 1, 3, 5, 7
-nonatetraenylidene, 1,3,5-heptatrienylidene, 3,5-dimethylene-1,
3,5-heptatrienylidene, 2,4-neopentylene-1,3,5-heptatrienylidene, 2-methine-4-propenyl-5,6-benzopyrylium, 1,3-pentadienylidene , 2-butenylidene, 3,5-trimethylene-1,3,5-heptatrienylidene, etc. In addition, since one heterocyclic residue has a positive charge, the substituent of that heterocyclic residue may have a negative charge, or I, Br, ClO ₄ ,
Salts may be formed with anions such as BF ₄ , p-toluenesulfonyl, and p-chlorobenzenesulfonyl. And in these cases -OH, -
COOH, _-NH2 , -CHO,

[Formula] A functional group such as -NCO is bonded directly to the heterocyclic residue or to the N atom of the heterocyclic residue via an alkyl group or the like. D2 Phthalocyanine dye The benzene ring of the phthalocyanine dye contains −OH,
-COOH, -NH ₂ , -COCl, -SO ₂ Cl, etc. are bonded together. As the central metal atom of the phthalocyanine, Pb, VO, Mn, Sn, Cu, etc. are particularly preferable. D3 squalirium pigment What is shown in Here, A and B each represent an aromatic ring, and the following are particularly preferred. In this case, R ₁ and R ₂ represent a substituent such as an alkyl group. In particular, the alkyl group is preferably -
Those to which functional groups such as OH, -COOH, and _-NH2 are bonded are preferable. D4 Choline or Corol A choline or corol proposed in Japanese Patent Application No. 1980-80487 with the above functional group bonded to it D5 Anthraquinone type Directly or through an alkyl group, -OH, -
D6 Azo type, especially bisazo type, trisazo type, azochrome type, etc., which have the above functional groups bonded to them. These dyes can be easily synthesized according to known methods. On the other hand, as the co-condensation component, the following are suitable. C1 Dialcohol Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
1,10-decanediol, 1,4-cyclohexanediol, p,p'-dihydroxy-2,2
-dicyclohexylpropane, bisphenol A, hydroquinone, p,p'-biphenol,
Hydroquinone dihydroxythyl ether, polyethylene glycol (n=2-50), etc. C2 Dicarboxylic acids and their acid chlorides Succinic acid, malonic acid, glutanoic acid, adipic acid, pimelic acid, suberic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, etc. Or these acid chlorides. C3 diamine 1,2-diaminoethane, 1,4-diaminobutane, hexamethylenediamine, diaminobenzyl, p,p'-diaminodiphenylmethane,
Diaminodiphenyl sulfide, diaminodiphenylsulfone, 3,3'-dichloro-4,4'-
Diaminodiphenylmethane, diaminodicyclohexylmethane, piperazine, 2,5-dimethylpiperazine, bisaminopropylpiperazine, 4,4'-diaminodiphenyl ether,
3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, isophorone diamine, etc. C4 di- or triisocyanate 2,4-tolylene diisocyanate, 2,6
- Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene diisocyanate, adduct polyisocyanate, etc. Coronate HL, Coronate AP, Coronate 2030, Coronate L, manufactured by Nippon Polyurethane Co., Ltd.
Demosyur N, Demosyur HL manufactured by Sumitomo Bayer Urethane, Takenate manufactured by Takeda Pharmaceutical Co., Ltd.
Various di- or triisocyanates such as D110N, LDI-100 manufactured by Kyowa Hakko Co., Ltd., and Millionate MS50 manufactured by Nippon Polyurethane Co., Ltd. C5 Diepoxy compound ethylene glycol diglycidyl ether,
propylene glycol diglycidyl ether,
Glycerol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyethylene glycol glycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6
-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether,
Fatty acid diglycidyl ether, terephthalic acid diglycidyl ether, spiroglycol diglycidyl ether, etc. C6 Acid anhydride Pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, cyclohexanetetracarboxylic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride acids, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, etc. C7 Dihydrazide Sebacic acid dihydrazide, adipic acid dihydrazide, isophthalic acid dihydrazide, etc. C8 Diiminocarbonate N,N'-p-phenylenebis (ethyleneiminocarbonate), etc. One or more of these pigments, or one
The at least one type of dye and at least one type of co-condensed component are subjected to a condensation reaction separately in advance according to a conventional method, and the resulting product is purified and used. In this case, conventional methods may be followed for heating, pressure reduction, catalyst, etc. Alternatively, depending on the case, it is also possible to dissolve the dyes and the like separately in the composition liquid for coating the recording layer, apply the solution, and then heat it to cause a condensation reaction. The dye polymer preferably contains about 2 to 20 molecules, particularly about 4 to 10 molecules of the dye. Although the recording layer of the medium of the present invention is made of a polymer of such a dye, the recording layer may contain other resins separately. At this time, coating properties are improved, and recording sensitivity, readout S/N ratio, etc. are improved. Examples of such resins include, for example, Japanese Patent Application No. 1983-
Those described in No. 15229 etc. are suitable. The resin is 50% by weight of the dye polymer.
Contained below. Preferably, such a recording layer further contains a quencher. This reduces reproduction deterioration and improves light resistance. Various quenchers can be used as the quencher, but in particular, when the dye is excited and singlet oxygen is generated, it undergoes electron transfer or energy transfer from the singlet oxygen and becomes excited, returns to the ground state by itself, and , is preferably a singlet oxygen quencher that converts singlet oxygen to the triplet state. Various substances can be used as singlet oxygen quenchers, but transition metal chelate compounds are particularly preferred because they reduce regeneration deterioration and have good compatibility with dye polymers. preferable. In this case, the central metal is preferably Ni, Co, Cu, Mu, etc., and the following compounds are particularly preferred. (1) Acetylacetonate chelate system Q1 Ni () acetylacetonate Q2 Cu () acetylacetonate Q3 Mn () acetylacetonate Q4 Co () acetylacetonate (2) Bisdithio-α-diketone system Here, R ⁽¹⁾ to ^{R (4)} represent a substituted or unsubstituted alkyl group or aryl group, and M is 2
Represents a valent transition metal atom. In this case, M has a single charge and may form a salt with a quaternary ammonium ion or the like. Q5 Ni()dithiobenzyl Q6 Ni()dithiobiacetyl (3) Bisphenyl dithiol type Here, R ⁽⁵⁾ and R ⁽⁶⁾ represent an alkyl group such as a methyl group, or a halogen atom such as Cl, and M represents a divalent transition metal atom such as Ni. Furthermore, a and b are each 0
or an integer less than or equal to 4. Further, M in the above structure may have a single charge and form a salt with an anion, and further, other ligands may be bonded above and below M. As such, the following are commercially available. Q10 PA-1001 (product name manufactured by Mitsui Toatsu Fine Co., Ltd.) Q11 PA-1002 [Ni-bis(toluene dithiol) tetra(t-butyl) ammonium as above] Q12 PA-1003 (same as above) Q13 PA-1005 [Ni as above] -bis(dichlorobenzene)tetra(t-bethyl)ammonium] Q14 PA-1006 [Ni-bis(trichlorobenzenedithiol)tetra(t-butyl)ammonium] Q15 Co-bis(benzene-1,2-dithiol)tetra Butylammonium Q16 Co-bis(0-xylene-4,5-dithiol)tetra(t-butyl)ammonium Q17 Ni-bis(benzene-1,2-dithiol)tetrabutylammonium Q18 Ni-bis(0-xylene-4 ,5-dithiol)tetrabutylammonium Q19 Ni-bis(5-chlorobenzene-1,2
-dithiol)tetrabutylammonium Q20 Ni-bis(3,4,5,6-tetramethylbenzene-1,2dithiol)tetrabutylammonium Q21 Ni-bis(3,4,5,6-tetrachlorobenzene-1,2 dithiol) tetrabutylammonium (4) dithiocarbamate chelate system Here, R ⁽⁷⁾ and R ⁽⁸⁾ represent an alkyl group. Moreover, M represents a divalent transition metal atom. Q22 Ni-bis(dibutyl dithiocarbamic acid) [Antigen NBC (manufactured by Sumitomo Chemical)] (5) Bisphenylthiol type Q23 Ni-bis(octyl phenyl) sulfide (6) Thiocatechol chelate type Here, M represents a divalent transition metal atom.
Further, M has a single charge and may form a salt with an anion, and the benzene ring may have a substituent. Q24 Ni-bis(thiocatechol)tetrabutyl ammonium salt (7) Salicylaldehyde oxime type Here, R ⁽⁹⁾ and R ⁽¹⁰⁾ represent an alkyl group, and M represents a divalent transition metal atom. Q25 Ni()0-(N-isopropylformimidoyl)phenol Q26 Ni()0-(N-dodecylformimidoyl)phenol Q27 Co()0-(N-dodecylformimidoyl)phenol Q28 Co()0 -(N-dodecylformimidoyl)phenol Q29 Ni()2,2'-[ethylenebis(nitrilomethylidine)]-diphenol Q30 Co()2,2'-[ethylenebis(nitrilomethylidine)]-diphenol Q31 Ni()2,2'-[1.8-naphthylenebis(nitrilomethylidine)]-diphenol Q32 Ni()-(N-phenylformimidoyl)phenol Q33 Co()-(N-phenylformimidoyl) Phenol Q34 Cu()-(N-phenylformimidoyl)phenol Q35 Ni()salicylaldehyde phenylhydrazone Q36 Ni()salicylaldehyde oxime(8) Thiobisphenolate chelate system Here, M is the same as above, R ⁽¹³⁾ and
R ⁽¹⁴⁾ represents a substituent such as an alkyl group or a hydroxyl group. In addition, other quenchers include the following. (10) Benzoate Q51 Existing chemical substance 3-3040 [Tinuvin-120
(manufactured by Ciba Geigy)] (11) Hindered amine Q52 Existing chemical substance 5-3732 [SANOLLS-770
(manufactured by Sankyo Pharmaceutical Co., Ltd.)] Such a quencher is synthesized according to a known method. The quencher is generally 0.05 to 12 mol, especially 0.05 to 12 mol per mol of the dye in the dye polymer.
It is contained in an amount of about 0.1 to 1.2 moles. Note that the maximum absorption wavelength of the quencher is preferably greater than or equal to the maximum absorption wavelength of the dye used. As a result, reproduction deterioration becomes extremely small. In this case, the difference between the two is preferably 0 or 350 nm or less. In order to form such a recording layer, it is generally necessary to apply the coating according to a conventional method, and the thickness thereof is generally as follows.
It is set to 0.03 to 100 μm. The thickness of the recording layer is usually 0.03 to 10 μm.
It is considered to be a degree. In addition, such a recording layer may contain other polymers or oligomers, various plasticizers, surfactants, antistatic agents, lubricants, flame retardants, stabilizers, dispersants, crosslinking agents, etc. Good too. To deposit such a recording layer, on the substrate,
What is necessary is just to apply|coat using a predetermined solvent and to dry. Examples of solvents used for coating include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, esters such as butyl acetate, ethyl acetate, carbitol acetate, and butyl carbitol acetate, and ethers such as methyl cellosolve and ethyl cellosolve. , aromatic systems such as toluene and xylene, halogenated alkyl systems such as dichloroethane, and alcohol systems. The material of the substrate on which such a recording layer is provided is not particularly limited, and may be any of various resins, glass, ceramics, metals, etc. Further, its shape may be a tape disk, a drum, a belt, etc. depending on the intended use. Note that the base body usually has a tracking groove. Further, if necessary, it may have a base layer such as a reflective layer, a heat storage layer, a light absorption layer, etc. Further, as the substrate material, a substrate without grooves, such as a highly heat-resistant epoxy resin, polycarbonate resin, polysulfone resin, polyethersulfone, or methylpentene polymer, is suitable. These substrates can also be coated with a primer to improve solvent resistance, wettability, surface tension, thermal conductivity, and the like. As the primer, for example, titanium-based, silane-based, or aluminum-based coupling agents, various photosensitive resins, and the like can be used. Further, on the recording layer, a reflective layer that functions as a back surface when a transparent substrate is used, various uppermost protective layers, a half mirror layer, etc. can be provided as necessary. The medium of the present invention may have the above-mentioned recording layer on one surface of such a substrate, or may have recording layers on both surfaces thereof. Also,
Two substrates with recording layers coated on one side are used, and the recording layers are placed facing each other with a predetermined gap between them, and they are sealed to prevent dust and scratches. You can also do it like this. Specific effects of the invention When the medium of the invention is running or rotating,
Recording light is irradiated in a pulsed manner. At this time, the dye in the recording layer is heated and the dye polymer and thermoplastic resin are melted, forming pits. The pits thus formed are read out by detecting the reflected or transmitted light of the readout light, particularly the reflected light, while the medium is running or rotating. In this case, recording and reading may be performed from the base side or from the recording layer side. It is also possible to erase the pits once formed in the recording layer with light or heat and rewrite. Note that the recording or reading light can be a semiconductor laser, He-Ne laser, Ar laser, He
-Cd laser etc. can be used. Specific Effects of the Invention According to the present invention, even if the medium is stored for a long time,
There is very little deterioration in writing sensitivity or S/N ratio. In particular, the deterioration of the S/N ratio when read after being stored at a high temperature after recording is extremely small. Furthermore, the read S/N ratio is extremely high. In addition, according to the second invention, reproduction deterioration is significantly reduced and light resistance is extremely high. The present inventors conducted various experiments to confirm the effects of the present invention. An example is shown below. Experimental Example 1 Using the following dyes A, B, C, D, and E and the following cocondensation components M and N, a dye polymer was synthesized by equimolar condensation. As a result of IR and thin layer chromatography measurements, it was confirmed that these all formed polymers. This polymer was dissolved in dichloroethane and deposited on a polymethyl methacrylate substrate to a thickness of 0.07 μm to form a recording layer. Further, the following resins R1 and R2 were added to these recording layers at a weight ratio of 20% based on the polymer to form recording layers. Separately, for comparison, a recording layer was formed in which the following dyes F and G and a resin were added at a weight ratio of 7:3. The dyes, cocondensation components, and resins used are as follows. Dye A 3,3'-di(2-hydroxyethyl)-
11-diphenylamino-10,12-ethylene-
5,6,5',6'-dibenzothiatricarbocyanine perchlorate dye B 5,5'-dichloro-11-diphenylamino-3,3'-di-(2-carboxyethyl)-
10,12-Ethylenethiatricarbocyanine perchlorate dye C Lead phthalocyanine-3,3'-dicarboxylic acid chloride dye D 3,3',4,4'-tetraaminovanadyl phthalocyanine dye E Hydroxysquarylium dye F 3,3'-diethyl-11-diphenylamino-10,12-ethylene-5,6,5',6'-dibenzothiatricarbocyanine perchlorate dye G 3,3',4,4'-tetraoctyloxycarbonyl lead phthalocyanine cocondensation Component M Hexamethylene dicarboxylic acid chloride cocondensation component N p,p'-diaminodiphenylmethane resin R1 α-methylstyrene (number average molecular weight 1
10,000) Resin R2 Polymethyl methacrylate (number average molecular weight 10,000) For each sample prepared in this way,
While rotating at 1800 rpm, a semiconductor laser (830 nm) or a He--Ne laser was focused to a diameter of 1 μm from the back side of the substrate (output of the focusing section 10 mW), and writing was performed with a pulse width of 100 nsec. After that, for those on which semiconductor laser writing was performed, a 1 mW semiconductor laser readout light was irradiated from the back side of the substrate as a 1 μsec width, 3 KHz pulse, and the reflected light was detected to measure the C/N ratio. . In addition, when performing He-Ne laser writing, C/N is determined by irradiating a He-Ne laser readout light with the same intensity and pulse as the semiconductor laser readout light from the recording layer side and detecting the reflected light. The ratio was measured. Next, each sample was stored at 50° C. and 90% relative humidity for 1000 hours, and then the deterioration of the C/N ratio was measured. Table 1 shows the deterioration rate (%) of the C/N ratio after storage.

[Table] From the results shown in Table 1, the effects of the present invention are clear. Experimental Example 2 Sample 25 was obtained by adding Quencher Q14 in a weight ratio of 50% to the dye polymer in Sample No. 2 of Experimental Example 1. 1mW, 1μsec, 300Hz for samples No.2 and No.25
Table 2 shows the reproduction deterioration rate (%) of the C/N ratio after irradiation with the readout laser beam for 4 minutes.

[Table] From the results shown in Table 2, the effect of the second invention is clear.

Claims (1)

[Scope of Claims] 1. An optical recording medium comprising a recording layer made of a dye polymer or a composition thereof on a substrate. 2. The optical recording medium according to claim 1, wherein the dye polymer is a homocondensate or a cocondensate of one or more dyes. 3. The optical recording medium according to claim 1 or 2, wherein the dye is cyanine, phthalocyanine, squalirium, choline or corrole. 4. The optical recording medium according to any one of claims 1 to 3, wherein the recording layer comprises a dye polymer composition containing a dye polymer and a resin. 5. An optical recording medium comprising, on a substrate, a recording layer made of a dye polymer or a composition thereof and further containing a quencher. 6. The optical recording medium according to claim 5, wherein the dye polymer is a homocondensate or a cocondensate of one or more dyes. 7. The optical recording medium according to claim 5 or 6, wherein the dye is cyanine, phthalocyanine, squalirium, choline or corrole. 8. The optical recording medium according to any one of claims 5 to 7, wherein the dye polymer composition contains a dye polymer and a resin. 9. The optical recording medium according to any one of claims 5 to 8, wherein the quencher is a transition metal chelate compound.