JPH02132663A - Optical recording medium - Google Patents

Abstract

PURPOSE:To prevent flawing and staining from the outside and to decrease the pitting deterioration of a magneto-optical recording layer by using a UV curing type compsn. of a photocation polymn. type as a protective layer. CONSTITUTION:An epoxy resin compsn. of the photocation polymn. type which does not contain acrylic acid, etc., and does not generate org. acids in high- humidity atmosphere, i.e. the UV curing type epoxy resin compsn. contg. an epoxy resin, aluminum compd., org. silicon compd. having a peroxysilyl group, and a photosensitizer is used for the protective layer 5. The phenomenon that the transition metal of the magneto-optical recording layer 3 is ionized by the org. acids, etc., to dissolve all the components is, therefore, prevented. The flawing and staining from the outside are prevented in this way and the pitting deterioration of the magneto-optical recording layer is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application in "Industry" 2] The present invention relates to an optical recording medium in which only reproduction or recording, iQ generation, and erasing can be performed using a light beam.

[Prior Art] Conventionally, protective layers in optical recording media have been disclosed in Japanese Unexamined Patent Publications No. 1235.9/1982 and Japanese Unexamined Patent Publication No. 13/1983.
Publication No. 3067. As disclosed in Japanese Unexamined Patent Publication No. 61-1:19961, Japanese Patent Publication No. 4\Kaishi 61-153844, etc., those made of ultraviolet curable acrylate resin compositions are used.

- Typical conventional optical recording media in which the magneto-optical recording layer is protected using the protective layer described in L are vacuum evaporation or sputtering on a resin substrate having guide grooves and a brief matte signal. SiN, SiOx,
A laminated film is formed by combining one or more types of inorganic dielectrics such as lnS and SiC, and one of them is GdTb.
, TbFe, GdTbFe, TbFeCo, Gd
An amorphous magneto-optical recording layer such as TbFeCo is provided, a laminated film similar to the inorganic dielectric is formed on the magneto-optical recording layer, and a protective film made of an ultraviolet curable acrylate resin composition is formed on top of the layer. A layer is provided to protect the magneto-optical recording layer.

The ultraviolet curable acrylate resin composition forming the protective layer usually includes (A) a Brevolimer component, and (B
) a reactive diluent component, (C) a photopolymerization initiator component, and the component (A). (R). (C
) usage ratio is (A) component 5-95% (B) component 95%
~5% (weight ratio). Component (C) is 0.1 to 10% (
(by weight) is used. (A)
The ingredients are polyol polyacrylate. Examples include polyester acrylate, urethane acrylate, and epoxy acrylate. Further, as the component (B), an acrylic ester of a polyhydric alcohol is used. As the component (C), a known photopolymerization initiator is used, and those with good storage stability after blending are particularly preferred.
Examples include penzoin alkyl ethers, acetophenones, probiophenones, anthraquinones, and thioxanthones. These are used singly or in a mixture of two or more in any proportion.

[Problems to be Solved by the Invention] However, in the conventional optical recording medium described above, by providing a protective layer made of the ultraviolet curable acrylate resin composition, the purpose of protection against external scratches and dirt cannot be achieved. However, when the optical recording medium is left under the conditions of an environmental durability test (70°C, 90% R.l.+., 2000 hours), there is a problem in that the recording characteristics become low F. In particular, when a magneto-optical recording layer is used as the recording layer, there is a problem that the Biut Error Rate (B.E.R.) increases compared to the initial stage, that is, the pitting corrosion of the magneto-optical recording layer increases. Ta. The present invention has been made to solve these conventional problems, by using a photocatalytic polymerization type epoxy resin composition as a protective layer. It is an object of the present invention to provide an optical recording medium that can prevent scratches and stains from the outside, exhibit extremely little pitting corrosion deterioration of the magneto-optical recording layer, and maintain long-term reliability.

[Means for Solving the Problems] and [Sakukawa] That is, the present invention comprises (a) an epoxy resin, (b) an aluminum compound, (C) an organosilicon compound having a beroxysilyl group, and (d) a photosensitizer. The present invention is an optical recording medium characterized by having a protective layer made of an ultraviolet curable composition containing a sensitizer.

The present invention will be explained in detail below.

In order to achieve the above objectives, the present inventor has conducted intensive research and found that the cause of the increase in pit error rate (B.E.R.) in environmental durability tests of conventional optical recording media is as follows.
In particular, when an amorphous magneto-optical recording layer is used as a recording layer and a protective layer made of an ultraviolet curable acrylate resin composition is formed, acrylic acid remaining in the ultraviolet curable acrylate resin composition, Transition metal It was also discovered that this phenomenon is caused by the dissolution of all components due to ionization.

In order to avoid the phenomenon described in "2", the present invention includes a protective layer with
Compared to the conventional UV-curable acrylate resin compositions mentioned above, acrylic acid. The characteristic # is to use a photo-cationic polymerization type epoxy resin composition that does not contain acrylic esters and acrylate groups and does not generate organic acids in a high humidity atmosphere.

The ultraviolet curable composition used in the present invention is an ultraviolet curable composition containing (a) an epoxy resin, (b) an aluminum compound, (C) an organosilicon compound having a beroxysilyl group, and (d) a photosensitizer. Consists of an epoxy resin composition.

(a) J&min epoxy resin used in the present invention is:
Examples include monofunctional epoxy compounds and polyfunctional epoxy compounds. Monofunctional epoxy compounds include, for example, bisphenol A epoxy resins: bisphenol F epoxy resins: phenol novolak epoxy resins: alicyclic epoxy resins; heterocyclic epoxy resins such as triglycidyl isocyanurate and hydantoin epoxy; water Added bisphenol A type epoxy resin, aliphatic epoxy resin such as flobylene glycol-dicrysyl ether, pentaerythritol-polyglycyl ether; reaction of aromatic, aliphatic or alicyclic carboxylic acid with shrimp chlorohydrin Glycidyl ether type epoxy resin obtained by: Glycidyl ether type epoxy resin which is a reaction product of a diallyl bisphenol compound having an allyl group at the ○1 position of each water group of bisphenol A and shrimp chlorohydrin, etc. is,
One or more selected from the group consisting of these may be used as appropriate.

The aluminum compound as component (b) used in the present invention is a compound having an organic group selected from the group consisting of an alkoxy group, a phenoxy group, an acyl group, a β-diketonato group, an 0-carbonylphenolate group, etc. It is preferable that In the above [%], as an alkoxy group,
Examples include methoxy group, ethoxy group, isobroboxy group, butoxy group, and examples of phenoxy group include phenoxy group, 0-methylphenoxy group. Examples of the acyloxy group include an acetato group, a propionato group, an imbropionato group, and examples of β-diketonato groups include an acetylacetonato group, a trifluoroacetylacetonato group, and a hexyloxy group. Examples include fluoroacetylacetonato group. Specific examples of the above aluminum compounds include trisme-1 xyaluminum, trisethoxyaluminum. Trisisoproboxyaluminum, trisphenoxyaluminum. Trisbara methylphenoxyaluminum, trisacetoxyaluminum. Examples thereof include trisethylacetoacetatoaluminum, trispropylacetoacetatoaluminum, and the like. It is possible to use one type or two or more types of these aluminum compounds, and the amount thereof is preferably in the range of 0.1 to 10 parts by weight per 1007i parts of the epoxy resin.

The organosilicon compound (c) having a beroxysilyl group of t used in the present invention includes those represented by the following formula (I).

(R' }?-si+o-O R2)4-n(
I) (wherein R1 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group, and R2 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, and R2 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, represents an alkyl group or an aryl group;
(n represents θ~3) The blending amount of these organosilicon compounds is as follows:
The range is preferably 0.1 to 10 parts by weight per 00 parts by weight.

The photosensitizer of component (d) used in the present invention is the above-mentioned (
It is possible to photosensitize the mixed composition of a), (b), and (c), or to use any compound capable of photosensitizing. Such photosensitizers include , such as aromatic hydrocarbons, penzophenone and its derivatives,
0-benzoylbenzoic acid ester, acetophenone and its derivatives, benzoin and benzoin ether and its derivatives, xanthone and its derivatives. Thioxanthone and its derivatives, cisulfite compounds. Examples include quinone compounds, halogenated hydrocarbons, and amines.

These photosensitizers can be used alone or in combination of two or more.
00 parts by weight. It is preferably 0.001 to 10%, more preferably 0.1 to 5%.

The ultraviolet curable composition of the present invention can be cured by photocuring or by a combination of both light and heat.

In addition, the thickness of the protective layer is 2 to 20 mm, preferably 5 to 20 mm.
Desirably 10 μm. Further, the protective layer can be provided on one or both sides of the optical recording medium.

In the present invention, the magneto-optical recording layer contains GdTb, Tb
Fc, GdTbFe, TbFeCo, GdTbF
Non-quality magnetic recording layers such as eCo may also be used.

Further, the substrate is not particularly limited, but may be made of, for example, polycarbonate resin, acrylic resin, polystyrene resin, polyolefin resin, etc., which have guide grooves and preformat signals.

EXAMPLES] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 FIG. 1 is an explanatory drawing showing an example of the method for producing an optical recording medium of the present invention. In the same figure, the guide groove and/or
or thickness 1.2 11 with pref saiichi matte signal
A SiJ4 layer 2 with a layer thickness of 800 layers was formed on a polycarbonate substrate 1 of No. 11 by the sputter link method, and then amorphous GdTb with a layer thickness of 400 layers and amorphous Tb with a layer thickness of 400 layers.
A magneto-optical recording layer 3 is provided by laminating Fe, and the layer thickness is approximately 100 mm.
0 Si. N. Layer 4 was deposited.

Next, as a photocationic polymerization type epoxy resin composition, (a) ERL 4299 (trade name, manufactured by UCC Corporation: alicyclic epoxy resin, epoxy equivalent 190-210)
97.5fi 1 part, (b) 1 part by weight of trisbropylacetoacetatoaluminum as a cationic polymerization catalyst, (c
) 1 part by weight of t-butylberoxyphenylsilane, (
d) The above Si. N. Spin coat on layer 4 (
Rotation speed 4000r. p. s, 7 seconds), and the layer thickness was 8Bm.
After forming the resin layer of d■ lamp 6 (233 on the irradiation surface
mW/cm2, wavelength: 165 nm) for 30 seconds to cure the resin layer, thereby creating an optical recording medium with a protective layer 5.

Example 2 The same procedure as in Example 1 was carried out except that 7-benzoin ethyl ether was used in place of penzophenone as the photosensitizer (d) used in the photocationically polymerized epoxy resin composition forming the protective layer of Example 1. An optical recording medium was created.

Example 3 As the photo-cationically polymerized epoxy resin set + A to form the protective layer, (a) epoxy resin and ER1 4206 (trade name, manufactured by UCC Corporation: alicyclic epoxy resin, epoxy resin)
Correct 70-74) Is tonnage part, ERL 11299 6
4.5 parts by weight, EIL 4211 (Product name. UCC
Manufactured by: Alicyclic epoxy resin, epoxy equivalent: 145)
8 parts by weight, (b) 1 trisacetoacetatoaluminum
Heavy μ part, (c) t-butylberoxyphenylsilane 1
An optical recording medium was prepared in the same manner as in Example 1, except that (d) a mixture of 0.5 parts by weight of xanthone was used as the photosensitizer.

Comparative Example 1 UV-curable acrylate S[l-17(
An optical recording medium was prepared in the same manner as in Example 1, except for using Nippon Ink Chemical Co., Ltd. (trade name).

Comparative Example 2 The same procedure as in Example 1 was carried out, except that a mixture of 96 parts by weight of EIIL 4299 and 4 parts by weight of diphenyliotonium hexafluorophosphate was used as a photocationic polymerization type epoxy resin composition for forming the protective layer. An optical recording medium was created.

Environmental durability test of optical recording media prepared in Examples 1 to 3 and Comparative Examples 1.2 (7°C, 90% R.l+., 200°C)
The occurrence of pitting corrosion in the recording layer after 0 hours) is shown in Table 1 below.

Table 1 From the results in Table 1, it can be seen that the optical recording media of Examples 1 to 3 did not cause pitting corrosion, whereas Comparative Examples 1 and 2 did have some pitting corrosion. E. It is recognized that R is increasing.

[Effects of the Invention] As explained above, the optical recording medium of the present invention prevents scratches and stains from the outside by using a photocationic polymerization type ultraviolet curable composition as a protective layer, and also has a magneto-optical property. There is extremely little pitting corrosion deterioration of the recording layer, and long-term reliability can be maintained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a method for manufacturing an optical recording medium in Example 1 of the present invention. l...Substrate 2,4...Si3N. Layer 3...Magneto-optical recording layer 5...Protective layer 6...U
V lamp

Claims (1)

[Scope of Claims] A protective layer consisting of an ultraviolet curable composition containing (a) an epoxy resin, (b) an aluminum compound, (c) an organosilicon compound having a peroxysilyl group, and (d) a photosensitizer. An optical recording medium comprising: