JPH03192547A - Optical disk and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical disc and a method for manufacturing the same.

[Prior Art] Conventional optical disks have been bonded together using a roll coating method using a hot-melt adhesive, an epoxy resin, an ultraviolet curing resin, or the like.

[Problem to be solved by the invention] However, the conventional technology had the following problems.

In the roll coating method, the adhesive has no heat resistance, so the optical disc is not reliable at high temperatures. In bonding with epoxy resin, the adhesive is cured by heat, so when heated, the adhesive overflows from the edge of the disk, spoiling the appearance of the optical disk, resulting in poor workability. It is extremely difficult to realize a double-sided optical disc using ultraviolet curing resin.

The present invention is intended to solve such problems, and its objectives are as follows. By bonding them together using a thermosetting adhesive and heating them, an optical disc becomes more heat resistant than a hot melt adhesive. By making it possible to temporarily fix the disc with light such as ultraviolet rays, the appearance of the optical disc will not be damaged by the adhesive overflowing from the outer edge of the disc, which is common when bonding using ordinary epoxy resin. Moreover, it is possible to easily realize double-sided optical discs, which is difficult to achieve with UV-curable adhesives.

[Means for Solving the Problems] The optical disc and the method for manufacturing the same of the present invention provide a single optical disc on which a recording layer is formed, in which a recording layer is not formed on the outer circumferential portion and inner circumferential portion of the substrate. After forming an organic film by spin coding method.

means for applying an adhesive to one of the two substrates on which the above-mentioned recording layer is formed, using two substrates on which the organic film is formed;
A means for spreading the adhesive by heating or leaving it to spread the adhesive by bonding it to another single plate of the optical disk on which the recording organic layer has been formed; Means for temporarily fixing the optical disk by curing the adhesive in the portion where the film is not formed.

It is characterized in that it is produced by means of leaving the temporarily attached optical disc as described above to harden the above-mentioned adhesive, and then heating to heat-cure the above-mentioned adhesive.

In the present invention, the organic film formed on the side where the recording layer is formed is preferably an ultraviolet curing resin, but in order to have good adhesion with epoxy, it is preferable to use epoxy (meth)acrylate or urethane (meth)acrylate. A mixture of organic substances containing oligomers and monomers is preferred. Alternatively, an organic layer made of epoxy resin or urethane resin cured by heat may be used. Further, the thickness of this organic layer is preferably 3 to 15 microns from the viewpoint of stress after curing and ease of curing, and more preferably 4 to 8 microns.

In the present invention, the adhesive includes at least an epoxy main ingredient and a curing agent, a mixture of an ultraviolet curable resin main ingredient and a curing agent, and an organic peroxide added thereto, or a compound 1 having an epoxy group and a (meth)acryloyl group. For example, a photopolymerization initiator, an epoxy curing agent, and, if necessary, an organic oxide is added to a partially (meth)acryloyl-modified epoxy compound such as bisphenol A, bisphenol F type, phenol novolac type, or cresol novolac type. It is recommended to use In these adhesives, the ratio of the total amount of epoxy groups to the total amount of (meth)acryloyl groups is 9
5 to 60%, (meth)acryloyl groups 5 to 40%
It is best to create it so that Hopefully epoxy group 90
to 80%, (meth)acryloyl group 10 to 20%
is appropriate.

Examples of epoxy base agents include bisphenol A, bisphenol F, and novolak.

or by adding a reactive diluent, which is a low viscosity epoxy.

It is better to use one without adding it. When the content of the reactive diluent increases, the viscosity of the adhesive decreases and workability improves, but the heat resistance of the adhesive layer decreases.

It is better to limit the amount of addition as it will reduce the reactivity and deteriorate the properties of the adhesive layer.

Epoxy curing agents include acid anhydrides, aromatic amines, aliphatic amines, amides, etc. Among them, it is best to use one with a poly-7 trilife of 1 to 50 hours at room temperature.
It is preferable to select a curing agent that can be cured at temperatures between 0°C and 80°C. Here, pot life is the time it takes to reach a viscosity that cannot be applied.

Examples of these include 2-ethyl-4methylimidazole, 1-benzyl-2-methylimidazole, 1-
Examples include imidazole series such as inbutyl-2-methylimidazole, and cycloaliphatic amines such as menthanediamine.

As the main ingredient of the ultraviolet curable resin, it is best to use one that has a relatively low viscosity at room temperature and one that has high reactivity; examples include 1. There are 6-hexanediol diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, tripropylene glycol diacrylate, etc., and these may be used as the main components.

As an example of the curing agent for the ultraviolet curable resin, one that absorbs at wavelengths longer than 300 nm is used. Examples include benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, benzoin, benzone ethyl ether, benzoin isobutyl ether, 1- (4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
Examples include 3.3-dimethyl-4-methoxybenzophenone.

Preferred examples of organic peroxides include those that decompose within several hours when heated from 40'C to 70'C; examples include di-n-propyl peroxydicarbonate, di-
Myristyl peroxydicarbonate, cumyl peroxy neohexanoate.

di(2-ethoxyethyl) peroxydicarbonate,
Di(methoxyisopropyl) peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanoate, 2.4
-dichlorobenzoyl peroxide, t-hexyl peroxypivalate.

t-butyl peroxypivalate, 3. 5. 5
- Trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxy octoate, succinic acid peroxide, acetyl peroxide, t-butyl peroxide (2-ethylhexanoate), m -) Ruyl peroxide, benzoyl peroxide, t-butyl peroxyisobutyrate, 1. 1-bis(t-butylperoxy)3,3.5-)limethylcyclohexane.

1. t-his(t-butylperoxy)cyclohexane, t-butylperoxymaleic acid, 1-butylperoxylaurate, t-butylperoxy3. 5
．． 5-trimethylhexanoate, cyclohexanone peroxide, t-butylperoxyallyl carbonate, t-butylperoxyisopropyl carbonate,
2. 5-dimethyl-2,5-di(benzoylperoxy)hexane.

2.2-bis(t-butylperoxy)octane.

t-butyl peroxyacetate, 2. Examples include 2-bis(t-butylperoxy)butane and t-butylperoxybenzoate. or.

A system containing cumene hydroperoxide or 1-butyl hydroperoxide, which have a high decomposition temperature, and an aliphatic amine as a reaction aid may also be used. However, in this case, the amine acts as a curing agent for the epoxy, so care must be taken in the amount added from the viewpoint of pot life.

In the present invention, the temperature at the time of bonding needs to be changed depending on the viscosity of the adhesive, and is preferably higher than room temperature, but is preferably 70° C. or lower in order to make it easier to obtain a constant constant temperature. More preferably from 40°C to 60°C
It is ℃. The substrate heating for curing the adhesive is preferably from 60°C to 100°C, depending on the curing temperature of the adhesive. More preferably the temperature is 70°C to 90°C.

In the present invention, as for the mixing ratio of epoxy and ultraviolet curing resin, the higher the mixing ratio of epoxy resin, the better the properties as an adhesive, and the ratio of epoxy and ultraviolet curing resin is 95% by weight.
: 5 to 70:30 is preferred. Here, epoxy refers to an epoxy main ingredient and a curing agent, and an ultraviolet curable resin refers to an ultraviolet curable resin in which an organic peroxide is added to the main ingredient and a curing agent.

In the present invention, if the bonding is performed under reduced pressure, the adhesive can be easily degassed and air bubbles are less likely to be incorporated into the adhesive layer.

In the present invention, it is preferable that the time for which the disks are left to stand after being bonded together and temporarily fixed by irradiation with light is set to be longer than the time for the adhesive to naturally harden. For example, if you leave it alone for 50
If the adhesive is bonded with an adhesive that loses fluidity and hardens over time, it is better to set the time to 50 hours or more.

[Example] The present invention will be explained below based on the drawings.

FIG. 1 is a basic configuration diagram of the disk according to the present invention,
1 and 9 are polycarbonate substrates, 2 and 10 are 5i
AIN layers, 3 and 11 are TbFeC0 layers, 4 and 12 are 5iAIN layers, 5 and 13 are Al-Tl layers, 6 and 14
is a ceramic layer.

7 and 15 are organic layers, 8 is an adhesive layer, and 16 and 17 are hard coat layers.

The polycarbonate substrates of Nos. 1 and 9 were formed by injection compression molding. The 5iAIN layer of 2 and IO is SiAl
The film was formed by RF reaction magnetron sputtering using a mixed gas of nitrogen and argon using a sintered target. 3 and 11 NdDyFe
The Co layer is D using an alloy target of NdDyFeCo.
The film was formed by C magnetron sputtering.

Similar to the 5iAIN layers 2 and 10, the 5iAIN layers Nos. 4 and 12 were formed by the RF reaction magnetron sputtering method by introducing a mixed gas of nitrogen and argon. The Al--Tl layers 5 and 13 were formed by DC magnetron sputtering using an At--Ti alloy target and introducing argon gas.

Ceramic layers 6 and 14 were formed by RF reaction magnetron sputtering using a sintered target of 5iAI and a mixed gas of nitrogen, oxygen, and argon.

The organic layers 7 and 15 were formed to a thickness of 5 μm using a spin-coding method using a mixture of trimethylolpropane triacrylate, 1,6-benzenediol diacrylate, and epoxy acrylate to which Ciba Geigy's Irgacure 907 was added. After forming the film, it is cured by irradiating it with ultraviolet light.

FIGS. 2(a) to 2(f) are schematic diagrams of the method for manufacturing an optical disc according to the present invention. 18 is a portion on the outer periphery of the substrate where the recording layer is not formed, 19 is a portion on the inner periphery of the substrate where the recording layer is not formed, 20 is an organic layer, 21 is a dispenser, and 22 is an adhesive applied in a ring shape. layer, 23 is a heater, 24 is a metal halide lamp, 25 is an ultraviolet light, 2
6 is an oven.

The adhesive layer in No. 8 is Evicron S-1 from Dainippon Ink and Chemicals.
29 and oil-based shell epoxy Ebicure IBMI-1
2 and 1. 6-hexanediol diacrylate and t-
A mixture of butyl peroxyisobutyrate and Ciba Geigy's Irgacure 907 is applied in a ring shape as shown in 22 on the side where the recording layer is formed, and then combined with another substrate in a vacuum system. Spread the adhesive on the bonded substrates using a heater (No. 23), and irradiate it with ultraviolet light using a metal halide lamp or high-pressure mercury lamp (No. 24).

The adhesive in the areas where the recording layer was not formed, such as Nos. 18 and 19, was temporarily cured, and then left to stand for 15 hours to cure the adhesive layer. Thereafter, the adhesive layer was cured by heating at 50°C for 3 hours, 60°C for 8 hours, and 80°C for 2 hours.

For the hard coat layers 16 and 17, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and Irgacure 907 manufactured by Ciba Geigy were spin-coded on the substrate surface, and then cured by irradiating ultraviolet rays with a high-pressure mercury lamp. It is something.

In addition, as the adhesive layer of No. 8, Ciba Geigy's Irgacure 907 was added to a bisphenol F-based epoxy resin in which 20% of all epoxy groups are acryloyl groups.
5%, oily shell epoxy Ebicure BMI-12
When an optical disc was prepared using 6% of γ-glycidoxypropyltrimethoxysilane and 3% of γ-glycidoxypropyltrimethoxysilane, with the other conditions unchanged from the configuration shown in Figure 1, the characteristics were almost the same as in Figure 1. We were able to create an optical disc with

Next, an example of creating an optical disc using a conventional method will be described. Optical discs bonded together using the roll foot method are
When a weather resistance test was conducted at 70° C. and 90% RH for 1000 hours, the recording layer was oxidized and the pit error rate increased. The optical disk according to the present invention shown in FIG. 1 was also tested at the same time, but there was no change in pit error rate. The optical disk bonded using a normal epoxy resin had a high viscosity at the time of bonding, so the adhesive layer was thicker, and the two-plane runout amount was larger than that of the optical disk according to the present invention shown in FIG.

The maximum power consumption was 7 milliradians for the ordinary one using epoxy resin, and the maximum power for the optical disk shown in FIG. 1 was 2 milliradians. Also, for optical discs that are bonded together using two ordinary epoxy resins.

When the adhesive cured, it overflowed from the outer periphery of the disc, spoiling the appearance of the optical disc. Temperature control is difficult with adhesives that cure with heat, and it is necessary to ensure that the substrate does not move while the adhesive layer is curing.If the adhesive is bonded with an adhesive that cures at room temperature, stress will be applied to the recording layer when the adhesive layer hardens. The envelope of the playback signal was disturbed and errors increased. As mentioned above, optical discs created using conventional methods have poor weather resistance.
It has problems such as a difficult manufacturing method and a low yield. However, it can be seen that the present invention provides an optical disc that is highly reliable and easy to produce without the problems that have conventionally occurred.

It should be noted that the present invention should not be considered limited to these examples (9 various modifications can be made without departing from the spirit of the present invention).

[Effects of the Invention] As described above, according to the optical disc and the manufacturing method thereof of the present invention, by bonding and heating using a thermosetting adhesive, an optical disc that is more heat resistant than a hot melt adhesive is produced. For optical discs, by making it possible to temporarily fix the disc using light such as ultraviolet light.

The adhesive does not overflow from the outer edge of the disc and spoil the appearance of the optical disc, which is common when bonding using ordinary epoxy resin, and it is easy to manufacture double-sided optical discs, which is difficult to do with UV-curable adhesives. This has the effect that it can be realized.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the optical recording medium according to the present invention.
FIG. 2(a) to FIG. 2(f) are schematic diagrams of the method for manufacturing an optical disc according to the present invention. 1, 9 ・ 2, 10 3, 11 4, 12 5, 13 6.14 7, 15 8 ・ ・ ・ 16, 1 18 ・ ・ ...Polycarbonate substrate - S1AIN protective layer - NdDyFeCo recording layer -・Protective layer of S IAIN・・AI layer・Ceramics layer・Organic layer・・Adhesive layer・・Hard coat layer・・Portion 19 on the outer periphery of the substrate where the recording layer is not formed・・・Substrate A portion 20 on the inner periphery where the recording layer is not formed...Organic layer 21...Dispenser 22...Adhesive layer 23 coated in a ring shape...
... Heater 24 ... Metal halide lamp 25 ... Ultraviolet rays 26 ... Oven or higher 7.15 ... 7M

Claims (1)

[Claims] A substrate on which an organic film is formed by a spin coating method on the surface on which the recording layer is formed of a single optical disk in which the recording layer is not formed on the outer and inner periphery of the substrate, and then the organic film is formed on the surface. using two discs, applying an adhesive to one of the sides on which the recording layer is formed, and bonding them together with the other optical disc veneer on which the organic layer has been formed, and then heating or leaving them. a means for spreading the adhesive, a means for temporarily fixing the optical disc by irradiating the bonded optical disc with ultraviolet rays to cure the adhesive in the portion where the recording layer is not formed, and a means for temporarily fixing the optical disc. 1. An optical disk and a method for manufacturing the same, characterized in that the optical disk is manufactured by leaving the optical disk to cure the adhesive, and then heating it to thermally cure the adhesive.