JPS6198710A - Disk - Google Patents

Abstract

PURPOSE:A disk for optical reading that is composed of a plurality of specific alpha, beta-unsaturated carboxylic acid derivative monomers in a specific proportion, thus showing high stability for a long period of time, without warpage and deflection, because of its good water absorption and deflection properties. CONSTITUTION:The objective disk is composed of a copolymer from (A) 30-95 wt% of a monomer of formula I (R<1> is H, methyl; R<2> is -CH2CH2O-, formula II; X, Y are Cl, Br, methyl, methoxy, phenoxy; k, l are 1-5 as k+l; m is 1-l3) or a mixture thereof, (B) 0-70 wt% of a polymerizable monomer of formula III (R<3> is H, methyl; R<4> is -CH2CH2O-, formula II, IV; Ar is residue of divalent phenol; n is 1-3; p is 0-4 where, when R<4> is -CH2CH2O-, or formula II, p is 0 or -when R <4> is formula IV, n is 1) or a mixture thereof, and (C) 5-30 mwt% of a polymerizable monomer of formula V (R<5> is H, methyl; R<6> is p-valent saturated aliphatic hydrocarbon which may include ether, ester or alcohol; q is 2-6).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to disks, particularly optically readable disks (digital audio disks, video disks, memory disks, etc.).

BACKGROUND OF THE INVENTION At present, inorganic glass and methyl methacrylate resin are mainly used as disc materials. However, since glass as a disc material does not have hygroscopic properties, it has little adverse effect on the recording film.

It has drawbacks such as being heavy, bulky, easily broken, difficult to process precisely, and expensive. On the other hand, in the case of methyl methacrylate resin, it is easy to mold and has advantages such as low cost), but it is also easily scratched, and the recording film layer is easily attacked due to the hygroscopicity of the resin (and the disc is easily warped). is a drawback.

Polycarbonate is also being considered as a new disk material, but it has the disadvantages that residual stress during molding tends to cause molecules to become oriented, resulting in birefringence, and the surface strength is low, making it easily damaged.

Problem 1 to be solved: The purpose of the present invention is to provide a disk with excellent properties, which is highly reliable over a long period of time, and which is less warped than resins used as conventional resins for disks. The goal is to supply fewer discs.

Another object of the present invention is to provide a disk that is less likely to be scratched, has less deflection, and has less hygroscopicity by taking advantage of the lightness and low cost of plastic materials.

Other objects and novel features of the present invention will become apparent from the description herein below.

A method for solving the problems The disk material of the present invention has the following formula: (A) General formula (I) [wherein R' represents H or CH3, R2 represents CR3 -CH2CH20- or CHCl~+20-] , x, yu may be the same or different, CI , [3
r, CR3,'C)130 or C(I+-15'0, k, lj are integers satisfying k+Q=1 to 5,
■represents an integer from 1 to 3] 30 to 95, or a mixture thereof, represented by 30 to 95
(B) General formula (I) CIb"C-Coo-(R'+B→Ar 0-(R9 pieces Ar O-[kufR4q OCOG-CH2 [wherein, R3 represents H or CH3 , R4 is CR3 -CH20H20-, -CHCl-120- or -CH
2CHCH20, A"represents a residue of divalent)H enol, n represents an integer from 1 to 3,
P represents an integer from 0 to 4, but when R4 is CR3 -CH20H20- or -〇HCH20-, n=
0, and when R4 is -CH2CHCH20, n=1] H2 or a mixture thereof O~70% and (C) general formula (I[[) R5 (CH2= C-Coo←-Re (III
) [In the formula, R5 represents H or CH3, R6 represents a saturated aliphatic hydrocarbon group which may contain an ether, ester, or alcohol with a valence q, and 'q represents an integer from 2 to 6] 5 to 30 polymerizable IN polymers or mixtures thereof represented by
% by weight, and consists of components (A), (B) and (
The disc is made of a copolymer in which the total amount of C) is 100% and is readable using at least light.

Specific examples of the polymerizable monomer represented by the general formula (I) of the present invention include 3'r.

The monomer of the general formula (I) used in the present invention (
In order to achieve the object of the present invention, B) should be O to 70% by weight, preferably 0 to 67% by weight, more preferably O to 6% by weight.
It is used at 5% by weight (0% by weight is the monomer (B)
(including cases in which it does not exist).

By containing the monomer (B), peeling from the mold due to curing shrinkage is minimized and toughness is improved.

Examples of such monomers include CH2= CH-COOC; H2CI (20-CH2
-CCOOCHCH20 CH2= CH-COOG )h CRG )(20-
H (R=H or CH3) CH2-CH-C; OOCH2CH2O--CH=C
Examples include H2 r -CH-(:1-h (Jl-1 CH2OCOCH= CH2 Cl-13 Hibikiichi0C17CHOCO-CH=C)12.

In the present invention, the monomer (C) of the general formula (I[[)
In order to achieve the purpose of the present invention, 5 to 30% by weight,
Preferably 10-27%, more preferably 15-2%
Used for lifting 5% of heavy ships.

The use of monomer (C) is suitable for increasing the crosslinking density and improving the solvent resistance, hardness, etc. of the copolymerized cured product.

Examples of the monomer (C) include C) lz -CH-C00Cth CI (20G OC
I-1=CH2C'rb=CH-COOC[2
CHCH20COCHH =CHt CH3 Akebono C1-12-CHCOOC) □b□-CCH20COC
H■ CH3 =CHz CH2= CHCOOCH2\Cto12 = CH-COOC)to C-CtoshiC
H2OH2= CHCOOC14/ CH2= C,H-COOCK C) OC) &
Ctob -CH2= CHCOOCH2, Ctod = CI-1-COOC)-re - C-C
H2-0-CH2-CH2= CH-COOC)b
/ , ct-bococt-+=c)-12C-CH2OC
OCH= CH2 ゝ゛C) 700000H=CH2 Cto(3 [CHi-CHCO70 (OH2) s CO+ 3
--OCII, -GeH4-CHCOOC)ttchi.

may be equal or different, and X
, Y, and Z at the same time (Ch-CHCOOCH2+c Get 'J 't
'Yes'11 The sum of b and C is 6, and the product of a and b represents a number selected from 2.4.6].

These monomers used in the present invention (however, 1i1 body (A), (B) and (C) (7) Q total 100
The mixing ratio of fi1%) cannot be determined unambiguously because it depends on the type and amount of each monomer used, but if the ratio of monomer (A) exceeds 95% by weight, copolymerization will occur. The surface hardness, heat resistance, and solvent resistance of the cured product are unfavorable because they are insufficient; on the other hand, if it is less than 301ffi%, the surface hardness and solvent resistance of the copolymerized cured product will be increased) Impact resistance is low,
I don't like it.

In addition, the usage ratio of monomer (C) is monomer (A) and (B).
Although it cannot be determined unambiguously because it varies depending on the type and amount used, the structure of monomer (C) itself, the number of functional groups, etc., it is up to 30% by weight at most.

A disk can be manufactured from the composition according to the present invention by radical polymerization using a radical polymerization initiator. As the polymerization method, not only thermal polymerization but also a polymerization method using active energy rays such as ultraviolet rays and γ rays can be used, and by either method, a disk free of optical distortion can be obtained in a short time.

In particular, polymerization using ultraviolet rays is particularly suitable in the present invention because copolymerization can be carried out in a short period of time, and production is not only significantly increased, but also a cured product with little optical distortion can be obtained.

When carrying out thermal polymerization, common radical polymerization initiators such as benzoyl peroxide, diisopropyl peroxydicarbonate, and azobisisobutyronitrile can be used.

In the case of ultraviolet curing, commonly known benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl needle, 2-human Oxy-2-benzoyl propane, azobisisobutyronitrile, benzyl ,
Photosensitizers such as thioxanthone and diphenyl disulfide can be used. These radical polymerization initiators or photosensitizers have an amount of at most 5% relative to the copolymer composition.
It is used in hard form with a weight of about 96. Furthermore, when using radiation such as gamma rays, it is generally not necessary to add a polymerization initiator.

The copolymer composition according to the present invention includes an anti-yellowing agent (for example, trioctyl phosphite, etc.) in addition to the above-mentioned monoω substance,
Leveling agents (fluorosurfactants, etc.), UV absorbers [e.g. 2-(2-hydroxy-5-methicifinyl)]
-2H-benzotriazole, etc.] can be added within a range that does not interfere with polymerization and curing.

Furthermore, the production of the disc according to the present invention involves injecting the copolymer composition into a disc mold assembled from a glass mold and a spacer, heating it, irradiating it with ultraviolet rays or irradiating it with other active energy rays, and curing it. It is done by molding.

Friend-1-1 The present invention will be described in detail below based on examples.

Example 1 2.4.6-tribromophenoxyethyl acrylate-6
60 parts by weight, 2,2-bis[4-(β-acryloyloxyethoxy)phenyl]propane 25 parts by weight, dipentaerythritol hexaacrylate 15 parts by weight, 2-
0.1 part by weight of benzoyl-2-hydroxypropane was mixed and stirred well to uniformly dissolve. Thereafter, it was poured into a glass mold consisting of two glass plates and a spacer, and irradiated with ultraviolet rays from the surrounding area using an aKW & pressure mercury pressure water tail lamp with a lamp input of 80W/α. After curing for 2 minutes, the mold was released and the thickness was 1.2. A disk substrate with a uniform thickness and a diameter of 30 Cfn was obtained.

The obtained disk was transparent, had better warpage and bending properties than polymethyl methacrylate (PMMA), and had significantly better resistance to scratches, PJ scratches, and water absorption than PMMA, and was excellent as a disk. Note that the warpage, bending characteristics, MS resistance, and water absorption of the disks were investigated according to the following methods.

Soli: Polymerization, after release from the mold, 3C center of the disc at 60'G)
Support with wφ jig and keep warm for 5 hours. The warping of the disc at that time was observed.

Bending properties: 15M x 170mm x 1.2mm board with a width of 15mm)
Then, a load of 200 g was applied to the center, and the difference between the position at that time and the position when the load was Og was measured.

A load of I kg was applied using scratch-resistant steel wool #1000, and the degree of scratching was observed.

Water absorption: The disk was left in water for 2 days, and the amount of water absorbed by the disk was determined from the difference in weight before and after, and this was used as a measure of water absorption.

This water absorption ω is shown as a relative layer when 0R-39 is set as 1.

Example 2 A disk was examined for warping, warping, etc. in the same manner as in Example 1, except that 80 parts by weight of 2.4.6-tribromophenoxyethyl acrylate and 20 parts by weight of dipentaerythritol hexaacrylate were used.

Example 3 60 parts by weight of 2.4.61-ripromphenoxyethyl acrylate, 35 parts by weight of 2.2-bis[4-(β-acryloyloxyethoxy>phenyl]propane, and 5 parts by weight of trimethylolpropane triacrylate) A disk was obtained in the same manner as in Example 1 except for this, and was examined for warpage and the like.

Example 4 40 parts by weight of 2.4.6-tribromophenoxyethyl acrylate, 40 parts by weight of 2.2-bis[4-(β-acryloyloxyethoxy)phenyl]propane, 20 parts by weight of dipentaerythritol hexaacrylate A disk was obtained in the same manner as in Example 1 except that the disk was inspected for warpage and the like.

Table 1 shows the results of investigating the monomer composition, warpage, etc. of Examples 1 to 3 above.

Examples 5 to 6 and Comparative Examples 1 and 2 Various disks having the monomer compositions shown in Table 1 were prepared by the same method as in Example 1, and the results are shown in Table 1. Table 1 shows CR-39 and PMMA as comparative examples.

Example 7 2.4.6-tribromophenoxyethyl acrylate-6
60 parts by weight, 25 parts by weight of 2.2-bis[4-(β-acryloyloxyethoxy)phenyl]propane, 15 parts by weight of dipentaerythritol hexaacrylate, and 1 part by weight of penzoyl peroxide were mixed and uniformly dissolved. Ta. Thereafter, it was poured into a glass mold consisting of two glass plates and a spacer, and heated at 45°C for 2 hours, at 50°C for 20 hours, at 70°C for 10 hours, and at 90°C in a hot air humidity chamber.

Heat cured for 2 hours, thickness 1.211+1s diameter 30α
A disk of average size was obtained. The resulting disc.

Like the one obtained in Example 1, it was an excellent disc.

(Left below) and Ha and dead weight (1) According to the present invention, as shown in Table 1 above, the present invention has better warpage, water absorption, bending properties, etc. required for a disk than the conventional product shown in the comparative example. It was significantly superior in its performance.

(2) In a disk, the occurrence of warpage causes the aperture lens to become out of focus during recording and playback, resulting in the inability to play back recording, but the disk of the present invention is superior to polycarbonate and polymethyl methacrylate in terms of warpage. It is much superior to other materials and can prevent warping.

(3) The disk according to the present invention has low water absorption, and therefore has the advantage that not only is the disk deflection small, but also long-term stability of the disk can be obtained in terms of recording protection.

(4) The disc according to the present invention has scratch resistance comparable to that of polycarbonate, superior to polymethyl methacrylate, and less prone to scratches.

(5) According to the present invention, it is possible to provide a disk material that takes advantage of the light weight and low cost of plastic materials, has the advantages of polycarbonate and polymethyl methacrylate, and improves the disadvantages of these materials. , is of great industrial significance.

(6) In addition, the disk of the present invention is easy to mold,
As a method for molding the disk, photocuring (
In addition to the cast polymerization method, the thermal polymerization (cast mold) method can also be used, and has great industrial value.

[Field of Application] The copolymer of the present invention is particularly suitable for digital audio discs, video discs, memory discs, etc. that record (write) and reproduce (read) information such as video and audio using light. So, the disk is generally
A metal reflective surface made of aluminum or the like is formed on a disk substrate (disc) that has information recording parts such as bits.
Generally, a plastic retainer 1119 is formed, but the present invention is suitable for application to such a disk substrate.

However, the present invention may also be applied to so-called capacitance conversion type information recording discs, etc., which use a reproducing needle having an electrode and read information by changing capacitance due to contact and movement of the electrode needle.

Claims (1)

[Claims] At least for discs that use light as a reading method, (A) General formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) [In the formula, R' represents H or CH_3, R^2 is -C
Represents H_2CH_2O- or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and X and Y may be the same or different, and Cl, Br
, represents CH_3, CH_3O or C_6H_5O,
k and l are integers satisfying k + l = 1 to 5, m is an integer of 1 to 3] Polymerizable monomers or mixtures thereof 30 to 95
Weight% and (B) General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R^3 represents H or CH_3, and R^4 represents -
CH_2CH_2O-, ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼, Ar represents the residue of divalent phenol, n represents an integer from 1 to 3,
P represents an integer from 0 to 4, but R^4 is -CH_2CH
＿O- or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, then P = 0, and R^4 is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, then n = 1] Polymerizability shown by 0 to 70% by weight of a monomer or a mixture thereof, (C) General formula (III) ▲ Numerical formula, chemical formula, table, etc. ▼ (III) [In the formula, R^5 represents H or CH_3, R ^6 represents a saturated aliphatic hydrocarbon group which may contain an ether, ester, or alcohol with a valence q, and q represents an integer of 2 to 6] Polymerizable monomer or mixture thereof 5 30% by weight, and the total amount of components (A), (B) and (C) is 100%.