JPH0467331A - Optical disk - 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 [Field of Industrial Application] The present invention relates to an optical disc on which information is recorded and reproduced using light such as a laser.

[Conventional technology]

Optical discs have attracted attention as high-density, large-capacity information recording media, and research and development of various types of optical discs is being carried out.

Among these, magneto-optical disks, which are erasable and freely rewritable, have a wide range of applications and have high expectations for the future. For this reason, various materials and systems have been announced, and their practical application is expected.

These optical discs require antistatic treatment to prevent the adhesion of flakes, etc., and this usually involves coating the surface of the substrate with an antistatic agent or kneading the antistatic agent into the substrate. is taken. However, the former treatment has problems with durability, and the latter has problems with moldability and light transmittance.

On the other hand, since polycarbonate resin or the like is generally used for the substrate of an optical disk, the surface hardness of the substrate is low. Therefore, in order to avoid damage to the surface, it has been proposed to perform surface hardening treatment using a UV hardening resin or the like.

However, coating by coating with these UV curing resins,
During the rotation of the disk, the resin is charged due to friction with the air, and the readout surface is often dirty due to the adhesion of dirt and dust, reducing the reliability of recording and readout signals.

[Problem to be solved by the invention]

An object of the present invention is to provide an optical disc that has excellent durability, antistatic properties, and sufficient surface hardness.

[Means to solve the problem]

In the present invention, at least the light irradiation surface (reading surface) of an optical disk is represented by the general formula (I) [wherein R1 and R1 are hydrogen atoms or methyl groups, n is an integer of 1 to 23, and m is 1 or 2]. 0.1 to 60% by weight of a mono- or diphosphoric acid ester compound of a mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide represented by the following integer:
An optical disc characterized in that it is coated with a coating film formed by curing a curable resin composition contained therein.

The optical disk of the present invention includes a bit-type optical disk consisting of a recording medium in which bits are formed on a substrate made of resin or the like, and a recording medium in which a thermal recording layer is formed on a substrate, and the optical disk is formed by irradiation with laser light or the like. These include bubble-type optical disks that form bubbles and detect level fluctuations based on changes in reflected light, and magneto-optical disks that are made of recording media in which a magneto-optical recording layer is formed on a substrate.

The light irradiation surface of an optical disk is a surface onto which a reading and/or writing light beam is incident, and is usually the surface of a substrate made of resin or the like, opposite to the surface on which the recording layer is formed. For example, in a magneto-optical disk, the light irradiation surface is a flat surface on which no groups are formed.

The present invention provides that at least the light irradiation surface (reading surface) of the optical disc is made of a mono- or diphosphoric acid ester compound of a mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide represented by the general formula (I). It is characterized by being coated with a coating film formed by curing a curable resin composition containing % by weight.

In general formula (1), R+ and Rt represent a hydrogen atom or a methyl group, n represents an integer of 1 to 23, and m represents an integer of 1 or 2.

Among these, n is preferably 1-15, particularly preferably 1-10.

Examples of the mono- or diphosphoric acid ester compound of the mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide represented by the general formula (I) are as follows.

C.I.

Live [CHz=C-CO(OCHzCHz)RO]□POH
[CH! = [Jl-Co(QC)IICult) n
O]tPOtl (in the formula, n represents an integer of 1 to 23), and more specifically, CHt=CH-COOCHzCl(zOP(OR)z
(Light ester DM.

Kyoeisha Yushi ■), Cal ■), CHz=CH-Co(OCHzCHz) -0P(01
1) x Cal ■), Unichemical ■), Unichemical ■), CH.

(CHz□C-C00CHzCHzO) -0P(OH
)s-1I (where n is 1 or 2) (RW-116
2HP, manufactured by Nippon Nyukazai ■), etc.

The mono- or diphosphoric acid ester compound of the mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide represented by the general formula (I) of the present invention is preferably 0.1 to 60% by weight in the curable resin composition. is 0. 2 to 50% by weight, particularly preferably 0.5 to 5%
Contains 0% by weight. If the amount of the compound is less than 0.1% by weight, the antistatic effect will be insufficient, while if it exceeds 60% by weight, the surface hardness of the coated optical disc will be insufficient, which is not preferable.

In the present invention, generally known polymerizable monomers, polymerizable oligomers, and polymerizable prepolymers are used. For example, bisphenol A epoxy acrylate, fatty acid-modified epoxy acrylate, novolac epoxy acrylate, phenol novolac epoxy acrylate, polyester oligourethane acrylate, polyfunctional hydroxy compound urethane acrylate, polybutadiene acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexaacrylate Aliphatic polyfunctional acrylates such as (meth)acrylate, trimethylolpropane tri(meth)acrylate, di(meth)acrylate of (poly)alkylene glycol, polyfunctional oligoester acrylate, polyfunctional polyester acrylate, acrylate modified products of phosphazene compounds , polyfunctional acrylate of isocyanuric acid, other vinyl polymerizable compounds, acrylic polymerizable compounds, etc. can be used. These polymerizable compounds may be used alone or in combination.

The curable resin composition of the present invention is used by adding a radical polymerization initiator such as a photopolymerization initiator and a thermal polymerization initiator, if necessary.

Photopolymerization initiators include benzophenone initiators such as benzophenone and Michler's ketone, diketone initiators such as benzyl and phenylmethoxydiketone, acetophenone initiators such as acetophenone, and benzoin initiators such as benzoin ethyl ether and benzyl dimethyl ketal. , thioxanthone-based starters such as 2,4-diethylthioxanthone, and quinone-based starters such as 2-methylanthraquinone and camphorquinone are preferably used.

If necessary, it is also possible to use a promoter such as an amine promoter.

The amount of initiator used is 0.1 to 10% based on the composition.
phr, preferably 0.5 to 7 phr is used. In addition, in the case of heat curing, azobisisobutyronitrile (A
IBN), benzoyl peroxide (BPO), cumene hydroperoxide, dicumyl peroxide, dibutyl peroxide, lauroyl peroxide, and the like.

The curable resin composition of the present invention is diluted with a solvent as necessary to improve coating properties and workability. Note that when polycarbonate resin is used as a substrate, alcoholic solvents such as methanol, ethanol, and isopropanol are preferably used.

The optical disc may be coated with the curable resin composition before or after the recording layer is formed.

The curable resin composition of the present invention can be coated on the surface of an optical disc by a known spin coating method, dip coating method, coating with a doctor knife, or coating with a bar coater.

When coating an optical disk, the antistatic effect can be improved by also coating the side surfaces of the optical disk.

The thickness of the coating film of the present invention after curing is 2 to 30 μm,
Preferably it is 5 to 25 μm.

The optical disk coated with the curable resin composition is cured by known methods and conditions using an ultraviolet lamp such as a low-pressure mercury lamp, medium-pressure mercury lamp, or high-pressure mercury lamp, a halogen lamp, active light such as an electron beam, or heat treatment. Ru. In this,
From the viewpoint of operability and productivity, it is preferable to use actinic light such as an ultraviolet lamp, a halogen lamp, or an electron beam.

The surface resistance of the optical disc obtained by the present invention is 19150
It is preferable that the resistance is less than 7 points, and those having a resistance higher than this are ineffective from the viewpoint of antistatic properties.

Further, from the viewpoint of handling, the surface hardness preferably has a pencil hardness of H8 or higher.

〔Example〕

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

In the examples, the surface resistance (Ω/mouth) is JISK-69
According to 11. The pencil hardness is JIS K-540.
0, and was measured using a Uni manufactured by Mitsubishi Pencil.

Examples 1 to 6, Comparative Examples 1 to 2 130 mm diameter, ISO standard compliant format, CCS
5iN (1300
people) / TbFeCo (200 people) / 5iN (350 people) /,! A recording layer with a laminated structure of alloy (400 layers) [the thickness of each layer is shown in parentheses] is formed by sputtering, and an ultraviolet curable resin containing phenol novolac acrylate as the main component is coated on the A1 alloy reflective layer. It was formed to a thickness of IO μm.

The flat surface of this disk is coated with a curable resin composition (N5C-7106, manufactured by Nippon Sekihi ■) and a mono- or diphosphoric acid ester compound (copolymerized) of a mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide. 5-10 μm
The coating was applied using a spin cord method to a thickness of . Subsequently, using a high-pressure mercury lamp with a length of about 27 C1 m and 2 Kw, ultraviolet rays were irradiated from a height of 201 m for 1 minute to cure the coating film.

Copolymerization monomer: Light ester DM, CB manufactured by Kyoeisha Yushi ■ = Cll-C00CHzCHxOP (OB) t
, Hosmer M1 Unichemical ■Hosmer P, Niini Chemical ■Hosmer PE, Unichemical ■When these coatings were cured under the above curing conditions, the appearance was sufficiently cured and no stickiness indicating residual monomer was observed. Ta.

Regarding the hardened surface of the polycarbonate disk after curing,
Surface resistance and pencil hardness were measured.

Hosmer PP, Unichemical ■ RW-1162HP, Nippon Nyukaza ■ I3 [CH*□C-C00CI(zCLO]-P(OB)!
--(However, n is a mixture of 1 and 2) Comparative Example 1 is a case where no copolymerized monomer is used, and Comparative Example 2 is a case in which a kneaded antistatic agent sorbitan laurate (Japanese volume ratio ■ (manufactured by) in alcohol, applied and dried.゛The surface resistance of the magneto-optical disks obtained in Examples 1 to 6 and Comparative Example 1 was measured after being immersed in pure water at room temperature for 24 hours, but no change was found. The surface resistance of the magneto-optical disk of Comparative Example 2 after similar treatment was 2xlO''Ω/hole.

Example 7 Hexafunctional urethane acrylate oligomer (U1226A
, manufactured by Shin Nakamura Chemical Industry ■) 40% by weight, hexafunctional acrylate oligomer (KAYARADDPC60, manufactured by Nippon Kayaku ■)
) 20% by weight, and monoethylene glycol acrylate phosphate (Light Ester DM, manufactured by Kyoeisha Yushi ■) 4
0% by weight, photoinitiator Darocure 1173p 3phr
A curable resin composition consisting of the following was applied to a polycarbonate substrate of a magneto-optical disk having a recording layer having the laminated structure of Example 1, and photocured in the same manner as described above. The surface hardness of the obtained disk was F, and the surface resistance was 1, lXl0I! Ω
/It was a mouth.

Example 8 55% by weight of phosphazene hexaacrylate (U-1000, manufactured by Idemitsu Petrochemical Co., Ltd.) and phosphoric acid monoethylene glycol acrylate (Light Ester DM, Kyoeisha Oil & Fat ■)
In the same manner as in Example 7, a curable resin composition was photocured in the same manner as in Example 7. The surface hardness of the cured coating is HB
The surface resistance was 3.8×10 10 Ω/mouth.

Example 9 Phosphazene hexaacrylate (U-1000, manufactured by Idemitsu Petrochemical ■) 95% by weight and phosphoric acid monoethylene glycol acrylate (Light Ester DM, Kyoeisha Oil and Fat ■)
A curable resin composition consisting of 5% by weight (manufactured by Nippon Steel Co., Ltd.) and 5 phr of a radical initiator AIBN was spin-coded onto a polycarbonate substrate of a magneto-optical disk having a recording layer with the same laminated structure as in Example 1, and heat-cured at 80°C. Ta. The surface hardness of the cured coating film was HB, and the surface resistance was 5.2×10”Ω/mouth.

〔Effect of the invention〕

INDUSTRIAL APPLICABILITY The present invention can provide an optical disc that has highly durable antistatic properties and excellent surface hardness.

Patent applicant Teijin Co., Ltd. Agent: Patent Attorney Takashi Shirai

Claims (1)

[Claims] (1) At least the light irradiation surface of the optical disc is defined by the general formula (I
)▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In the formula, R_1 and R_2 are hydrogen atoms or methyl groups,
n represents an integer of 1 to 23, and m represents an integer of 1 or 2. ] 0.1 to 60% by weight of a mono- or diphosphoric acid ester compound of a mono(meth)acrylic acid ester compound of polyethylene oxide or polypropylene oxide represented by
An optical disc characterized by being coated with a coating formed by curing a curable resin composition containing the same.