JPH0467329A - Optical disk - Google Patents

Abstract

PURPOSE:To obtain the optical disk having excellent durability, an antistatic property and excellent surface hardness by coating at least the photoirradiated surface of the optical disk with a coated film formed by curing a curable resin compsn. contg. the ether deriv. of specific mono(meth)acrylate. CONSTITUTION:At least the photoirradiated surface (read surface) of the optical disk is coated with the coated film formed by curing the curable resin compsn. contg. 5 to 70wt.% ether deriv. of the mono(meth)acrylate of the polyethylene oxide or polypropylene oxide expressed by formula I. In the formula I, R1, R2 denote a hydrogen atom or methyl group; R3 denotes 1 to 9C alkyl group, phenyl group, phenyl group subst. with 1 to 9C alkyl group, phenyl substd. with 1 to 9C alkoxy group; (n) denotes 5 to 23 integer. The optical disk having the high durability, the antistatic property and the sufficient surface hardness is obtd. in this way.

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]

Various research and developments are being conducted on optical discs as high-density, large-capacity information recording media.

In particular, various materials and systems have been announced for magneto-optical disks that can be used to erase information in a wide variety of fields, and their practical use 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 had problems with durability, and the latter had problems with moldability and light transmittance.

On the other hand, since optical disc substrates are generally made of polycarbonate resin, the surface hardness of the substrate is low.Therefore, it has been proposed to perform surface hardening treatment using UV curable resin to avoid damage to the surface. There is.

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]

The present invention has antistatic properties with excellent durability, and
The purpose of the present invention is to provide an optical disc having 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 formed by the general formula (1) (wherein, Rt and Rz are hydrogen atoms or methyl groups, and R3
is an alkyl group having 1 to 9 carbon atoms, a phenyl group, and an alkyl group having 1 to 9 carbon atoms.
Phenyl group substituted with 9 alkyl groups or 1 carbon number
-9 phenyl group substituted with alkoxy group, n is 5
The composition was coated with a coating film obtained by curing a curable resin composition containing 5 to 70% by weight of an ether derivative of mono(meth)acrylic acid ester of polyethylene oxide or polypropylene oxide represented by This is an optical disc characterized by the following.

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 opposite to the surface on which a recording layer is formed on a substrate such as resin.

For example, in a magneto-optical disk, the light irradiation surface (reading surface) is a flat surface on which no groups are formed.

The present invention provides a method for controlling a small amount of the optical disc (also known as the light irradiation surface (reading surface)) containing 5 to 70% by weight of an ether derivative of a mono(meth)acrylic acid ester of polyethylene oxide or polypropylene oxide represented by the general formula (1). It is characterized by being coated with a V! film formed by curing a curable resin composition.

In the general formula (I), R", R, is a hydrogen atom or a methyl group, R1 is an alkyl group having 1 to 9 carbon atoms, a phenyl group,
n represents a phenyl group substituted with an alkyl group having 1 to 9 carbon atoms or a phenyl group substituted with an alkoxy group having 1 to 9 carbon atoms, and n represents an integer of 5 to 23.

Examples of the alkyl group having 1 to 9 carbon atoms in R1 include methyl, ethyl, propyl, butyl, pentyl, hexyl, and octyl groups, which may be branched. -4 methyl, ethyl, propyl, butyl groups are preferred. Also, carbon number 1
Examples of the phenyl substituted with an alkyl group of -9 include nonylphenyl, butylphenyl, methylphenyl, and the like.

In addition, in general formula (1), n represents an integer of 5 to 23, n
If n is less than 5, the philicity of the glycol residue will be low and sufficient static neutralizing properties will not be exhibited.On the other hand, if n exceeds 23, the solubility will decrease, which is undesirable.N is preferably 6 to 20.

As the ether derivative of mono(meth)acrylic acid ester of polyethylene oxide or polypropylene oxide represented by the general formula (1), for example, CFIt "CI-Co(OCHzCut) -0CR
s 1GHz=CI-CO(OCHtCHg), 0
CJs, CHg = C1l-CD (OCIltCllt
) -0PbCaHw (where n is 5 to 23, pH is p
-represents a phenylene group), and specifically,
CHz-C'-Co(OClltCIIg) *0CH
s (Methoxypolyethylene glycol #400 methacrylate), Lengelicol #1000 methacrylate), CFlz=CIl-Co(OCHzCHz)*0C
Fls (methoxypolyethylene glycol #400
acrylate), Nippon Nyuka Kaisha (■)), but are not limited to these.

The ether derivative of (meth)acrylic acid ester of polyethylene oxide or polypropylene oxide represented by the general formula (1) of the present invention is contained in the curable resin composition at 5 to 7
It is contained in an amount of 0% by weight, preferably 10 to 60% by weight, particularly preferably 15 to 50% by weight. If the amount of the compound is less than 5% by weight, the antistatic effect will be insufficient, while if it exceeds 70% by weight, the hardness of the surface coating of the optical disk coated with the curable resin composition and cured will be insufficient, which is not preferable.

In the present invention, generally known polymerizable monomers, polymerizable oligomers, and polymerizable prepolymers are used in the curable resin composition other than the compound of formula (1). 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 hexa(meth)acrylate , trimethylolpropane tri(meth)acrylate, di(meth) of (poly)alkylene glycol
Aliphatic polyfunctional acrylates such as acrylates, polyfunctional oligoester acrylates, polyfunctional polyester acrylates, acrylate modified products of phosphazene compounds,
Polyfunctional acrylates 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 may contain a radical polymerization initiator such as a photopolymerization initiator or a thermal polymerization initiator, if necessary. use Examples of 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 initiators such as 2,4-diethylthioxanthone, and quinone-based initiators such as 2-methylanthraquinone and camphorquinone.

If necessary, an accelerator such as an amine accelerator may be used in combination with the curable resin composition of the present invention.

The amount of initiator is 0.1 to 10 ph to the composition.
r, preferably from 0.5 to Tphr. Also,
In the case of heat curing, azobisisobutyronitrile (AIB
N), benzoyl peroxy F (BPO), ') menhydroperoxide, dicumyl peroxide, dibutyl peroxide, lauroyl peroxide, and the like.

The curable resin 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 method using a doctor knife, or method using 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 after curing of the present invention is 2 to 30 μm,
Preferably it is 5 to 25 μm.

The optical disk coated with the polymerizable monomer 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. be done. Among these, it is preferable to use actinic light such as an ultraviolet lamp, a halogen lamp, or an electron beam from the viewpoint of operability and productivity.

The surface resistance of the optical disc obtained by the present invention is 10IsΩ
/ mouth is preferred. 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 Mitsubishi Pencil 22.

Examples 1 to 4, Comparative Examples 1 to 2 130 mm diameter, ISO standard compliant format, CCS
5iN (1300
A recording layer with a laminated structure of (200 people) / TbFeCo (200 people) / 5iN (350 people) / A1 alloy (400 people) [the thickness of each layer is shown in parentheses] was formed by sputtering, and was deposited on the AI1 alloy reflective layer. A UV curable resin containing phenol novolac acrylate as the main component was formed to a thickness of about 10 μm.

On the flat surface of this disk, a curable resin composition (Japan Manufacturing Co., Ltd., N5C-7106) was coated with an ether derivative (copolymerized monomer) of monomethacrylic acid ester of the following polyethylene oxide (n=15) in an amount shown in Table 1. (% is weight%
) was applied to a thickness of 5 to 10 tIm by a spin cord method. Continuing, the length is about 2-7
Using a CI, 2Kw high pressure mercury lamp, the coating film was cured by irradiating ultraviolet rays from a height of 20CI for 1 minute.

Copolymerization monomer: MPG130MA, HMA-862 manufactured by Nippon Nyukazai ■, manufactured by Nippon Nyukazai ■ Table 1 Comparative example 1 is the case where no copolymerization monomer is used, and comparative example 2 is the case where the antistatic agent sorbitan is kneaded onto a polycarbonate substrate. Laurate (manufactured by Nippon Seihi ■) is dissolved in alcohol, applied, and dried.

When these coated products were cured under the above-mentioned effect conditions, the external appearance was sufficiently cured, and no residual stickiness indicating smearing was observed.

The surface resistance and pencil hardness of the cured surface of the polycarbonate disk after curing were investigated.

The results are shown in Table 1.

(The following is a blank space) The magneto-optical disks obtained in Examples 1 to 8 and Comparative Example 1 were immersed in pure water at room temperature for 24 hours, and then the surface resistance was measured, but there was no change.

The surface resistance of the magneto-optical disk of Comparative Example 2 after the same treatment was 2.
It was X101SΩ/mouth.

Example 9 Phosphazene hexaacrylate (U-1000, manufactured by Idemitsu Petrochemical ■) 80% by weight, methoxypolyethylene glycol #400 monomethacrylate 20% by weight, AI
A curable resin composition containing 5 phr of BN was spin-coded onto a polycarbonate substrate of an optical disc having a recording layer with the same laminated structure as in Example 1, and was heat-cured at 80°C.

The surface hardness of the cured coating is F, and the surface resistance is 7.3×101
It was 4Ω/mouth.

〔Effect of the invention〕

INDUSTRIAL APPLICABILITY The present invention can provide an optical disc having highly durable antistatic properties and sufficient 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,
R_3 is a phenyl group substituted with an alkyl group having 1 to 9 carbon atoms, a phenyl group, an alkyl group having 1 to 9 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms, and n is an integer of 5 to 23). An optical disc characterized in that it is coated with a coating film formed by curing a curable resin composition containing 5 to 70% by weight of the ether derivative of mono(meth)acrylic acid ester of polyethylene oxide or polypropylene oxide.