JPH09176239A - Optical disk substrate made from synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an optical disk substrate made from a synthetic resin and having an excellent clarity, a low birefringence, and low water absorption properties. SOLUTION: This substrate is prepd. from a polymer which is prepd. by polymerizing an ester of a dimer diol with an α,β-unsatd. carboxylic acid compd. represented by the formula: R1 (R2 )C=C(R3 )COOR6 (wherein R1 , R2 , R3 , and R6 are each H or 1-6C alkyl) and/or an ester of a trimer triol with the α,β- unsatd. carboxylic acid compd. or by polymerizing a mixture comprising these esters and a monomer copolymerizable therewith. The dimer diol is obtd. by hydrogenating a dimer acid (or its ester) which is a dimer of an 11-22C unsatd. higher fatty acid (or its lower alcohol ester). The timer triol is obtd. by hydrogenating a trimer acid (or its ester) which is a trimer of an 11-22C unsatd. higher fatty acid (or its lower alcohol ester).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a document file, a video file, a code data memory, a digital audio disc, a home and professional video disc,
The present invention relates to an optical disk base made of synthetic resin used for optical recording disks such as magneto-optical disks (MO).

2. Description of the Related Art Conventionally, compact discs (CDs)
As an optical disk base material used for a laser video disk (LVD), PMMA,
PC, glass, epoxy resin, etc. have been used. In particular, for a playback-only CD, a PC is a playback-only LV.
PMMA is often used for D. Optical disc base materials are required to have functions such as transparency, low birefringence, low water absorption, and high heat resistance. For example, PC with a benzene ring in the molecule has a large birefringence and PC is adopted. However, there is a problem in that the sound quality and the image to be reproduced are adversely affected by such a base. PMMA has a small birefringence but has a high water absorbency, and has problems such as warping of the substrate. Therefore, in PC, the molecular weight is lower than that of a general molding material grade, and various measures such as controlling the molecular orientation generated in the molding process are made. Further, in order to reduce the water absorption rate of PMMA, the water absorption rate is reduced by copolymerization with (meth) acrylic acid higher ester such as cyclohexyl methacrylate. However, a material satisfying both of these low birefringence and low-grade water has not been developed yet. Furthermore, PC and PMMA have a specific gravity of 1.2.
Considering the transportation of a large number of optical discs, which are relatively large, the use of a lightweight resin is attractive.

[0002]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a synthetic resin optical disk substrate which is excellent in transparency, has a small birefringence and has low water absorption.

The present invention is directed to specific dimer diols and / or trimer triols and specific α,
Mainly composed of an esterified product with β-unsaturated carboxylic acid,
By polymerizing a mixture of these esterified products and a monomer copolymerizable with each other, a transparent cross-linked polymer having excellent transparency and excellent physical properties due to a structure containing a large amount of aliphatic hydrocarbon chains is obtained. It was made based on the finding that the above problem can be efficiently solved by using this polymer.

That is, the present invention has 11 to 22 carbon atoms.
Esterification product of dimer diol obtained by hydrogenating dimer acid or dimer acid ester which is a dimer of higher unsaturated fatty acid or lower alcohol ester thereof and α, β-unsaturated carboxylic acid represented by general formula (I) (A) and / or trimer triol obtained by hydrogenating trimer acid or trimer ester which is a trimer of a higher unsaturated fatty acid having 11 to 22 carbon atoms or a lower alcohol ester thereof and represented by the general formula (I) Obtained by polymerizing an esterified product (B) with an α, β-unsaturated carboxylic acid or a mixture (D) composed of a monomer (C) copolymerizable with these esterified products. Provided is an optical disc base made of synthetic resin, which is composed of a united body.

Embedded image R ₁ (R ₂ ) C═C (R ₃ ) COOR ₆ (wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and R ₆ is Hydrogen or carbon number 1
Up to 8 alkyl groups are shown. )

The dimer acid or dimer acid ester for producing the dimer diol used in the present invention or the trimer acid or trimer acid ester for producing trimer triol has 11 to 22 carbon atoms, preferably 14 to 20 carbon atoms as a raw material. More preferably, an esterified product of a higher unsaturated fatty acid having 16 to 18 or a lower alcohol having 1 to 6 carbon atoms is used, and a Lewis acid or Bronsted acid type liquid or solid catalyst, preferably a montmorillonite-based catalyst is used as the raw material. It is obtained by adding activated clay to the raw material in an amount of 1 to 20% by weight, preferably 2 to 8% by weight, and carrying out a dimerization reaction at 200 to 270 ° C, preferably 220 to 250 ° C. The pressure during the reaction is usually slightly increased, but it may be normal pressure. The reaction time varies depending on the amount of the catalyst and the reaction temperature, but is usually 5 to 7 hours. The reaction system thickens as the reaction progresses. After completion of the reaction, the catalyst can be filtered off and then distilled under reduced pressure to distill off unreacted raw materials, isomerized fatty acids and the like, and then dimer acid fraction can be distilled off. Further, by distilling, a trimer acid fraction can be obtained.

The dimer acid and trimer acid thus obtained are then hydrogenated. At this time, dimer acid and trimer acid may be used alone or as a mixture. Next, in order to convert these dimer acids (including their esters, hereinafter the same) to dimer diols and trimer acids (including their esters, the same below) to trimertriol, a catalytic reduction method using hydrogen gas and a catalyst is used. A known method such as a reduction method using a hydrogenating agent such as lithium aluminum hydride, lithium borohydride, and metal sodium / alcohol can be adopted. That is, as a catalyst, Raney nickel, platinum-supported nickel diatomaceous earth, copper-chromium, copper-zinc and the like are used in an amount of 0.1 to 7% by weight with respect to the dimer acid or trimer acid, and the reaction temperature is 100 to 300.
℃, preferably 250 ~ 280 ℃, the pressure during the reaction is hydrogen pressure normal pressure ~ 300kg / cm ² , preferably 150 ~ 250kg
It is advisable to carry out the catalytic reduction at a reaction time of / cm ² and a reaction time of 1 to 15 hours, preferably 4 to 8 hours.

It is also possible to carry out the reduction in a solvent using a hydrogenating agent such as lithium aluminum hydride, lithium borohydride, metallic sodium / alcohol system, etc., in an equimolar amount or more with respect to dimer acid or trimer acid. Specifically, lithium aluminum hydride is used in an amount of 2 times mol for dimer acid and 3 times mol for trimer acid to disperse in diethyl ether or dioxane solvent, and dimer acid diluted with the same dispersed solvent. Or trimeric acid is added dropwise.
The reaction temperature is preferably from 0 ° C. to room temperature, and the reaction time is preferably from 1 to 2 hours. After completion of the reaction, after stirring at room temperature for about 30 minutes,
It is advisable to gradually add about 4 times mol of water to lithium aluminum hydride to end the reaction. Next, the reaction solution is washed with water and the solvent layer is distilled off to obtain dimer diol and trimer triol. Next, an esterification or transesterification reaction of dimer diol and trimer triol (hereinafter, also referred to as “polyhydric alcohol”) is performed. The α, β-unsaturated carboxylic acid used here has 3 to 6 carbon atoms. [Alpha], [beta] -unsaturated carboxylic acid and its alkyl ester having an alkyl group having 1 to 8 carbon atoms are preferable. Specifically, acrylic acid, methacrylic acid, crotonic acid or their methyl ester, ethyl ester, propyl ester, butyl ester, hexyl ester, octyl ester and the like can be mentioned. The α, β- used in the esterification or transesterification reaction
The amount of unsaturated carboxylic acids is 1.0 to 5.0, preferably 1.05 to 2.0 equivalents in terms of the amount of carboxylic groups with respect to the —OH group of the polyhydric alcohol as a raw material.

The esterification reaction uses paratoluene sulfonic acid, sulfuric acid, hydrogen fluoride, hydrogen trifluoride, methane sulfonic acid, etc. as a catalyst, and is preferably 0.1 to 10% by weight with respect to the raw polyhydric alcohol, preferably Is used at a reaction temperature of 50 to 150 ° C. for 3 to 10 hours. In the transesterification reaction, a metal alkoxide selected from titanium and aluminum as a metal atom is used as a catalyst in an amount of 0.01 to 10% by weight based on the raw material alcohol, and a reaction temperature of 50 to 150 ° C. is 3 to 10%. Good time to do it. In both reactions, 2,4-dimethyl-6-t-butylphenol, 2,4,6-trimethylphenol, 2,4-diethyl-6-t-butylphenol, hydroquinone and paramethoxyphenol, etc. 1 to 5000 pp with respect to the α, β-unsaturated carboxylic acid ester product of the polyhydric alcohol (hereinafter, also referred to as “α, β-unsaturated carboxylic acid ester”) as the product
m, preferably 10 to 1000 ppm. The α, β-unsaturated carboxylic acid ester thus produced can be purified by distillation under reduced pressure or washing with an alkaline aqueous solution, if necessary. The α, β-unsaturated carboxylic acid ester thus obtained can be used as a dimer ester alone, a trimer ester alone, or a mixture thereof. Among these, dimer ester / trimer ester = 100/0 to 20/80 (weight ratio) is preferably used in a mixing ratio, and more preferably 97/3 to 30/70 (weight ratio).

The dimer ester or trimer ester can be polymerized alone or as a mixture of the two to form a crosslinked resin. These esters are copolymerizable monomers in a range not departing from the gist of the present invention. It can also be copolymerized with the body. The copolymerizable monomer (C) is preferably used in the mixture (D) in an amount of 50% by weight or less. Examples of the copolymerizable monomer include various monomers having an acrylic group, a methacrylic group, a vinyl group and the like. Specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isoburu (meth) acrylate, and t.
-Butyl (meth) acrylate, n-hexyl (meth)
Α, β-unsaturated carboxylic acid ester represented by the general formula (I) having an aliphatic alkyl group such as acrylate and 2-hydroxyethyl (meth) acrylate (wherein,
R ₆ represents an alkyl group having 1 to 8 carbon atoms), phenyl (meth) acrylate, cyclohexyl (meth) acrylate, naphthyl (meth) acrylate, 1,2,3
-(Meth) acrylates having an aromatic group or an alicyclic group such as tribromophenyl (meth) acrylate, and further ethylene glycol di (meth) acrylate, polyethylene glycol poly (meth) acrylate, propylene glycol di (meth) ) Acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, trimethylolpropane tri (meth) ) Acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, 2,2-bis {4- (meth) acryloxyethoxyphenyl} propane, 2,2-bis {4- (meth) acrylate Acry Carboxymethyl and polyfunctional (meth) acrylates such as polyethoxy phenyl} propane, styrene, divinylbenzene, alpha-methyl styrene, vinyl compounds such as chloromethylstyrene are also used.

These monomers can be used alone or as a mixture of two or more kinds. Moreover, the copolymerizable monomer usable in the present invention is not limited to these monomers. In the present invention, the resin for optical disc substrate of the present invention is obtained by polymerizing or copolymerizing the above-mentioned esterified products (A) and / or (B), or these with the above-mentioned monomer or monomer mixture. As the polymerization method, radical polymerization, ionic polymerization, photopolymerization or the like can be adopted, and a usual radical initiator or photopolymerization initiator can be used. For example, in the method of radical polymerization, it is preferable to use an initiator that starts the polymerization reaction at a temperature of 30 to 120 ° C. The photopolymerization is carried out at a temperature of about room temperature, and a high pressure mercury lamp, a low pressure mercury lamp or the like is used as a light source. However, the resin of the present invention is obtained as a cross-linked polymer because the main components, dimer ester and trimer ester, are polyfunctional monomers. Therefore, it is practically impossible to use the obtained resin as a molding material accompanied with melting or melting. Therefore, as a polymerization method, a molded product can be directly obtained, which is suitable for the intended optical disk substrate form. It is preferable to use the cast polymerization method. More specifically, the monomer (A)
And / or (B) or (D) is poured into a mold such as glass having a cavity corresponding to a desired final shape, and the mold is heated from room temperature to 70 to 120 ° C. for about 1 to 30 hours. A synthetic resin optical disc substrate can be obtained by raising the temperature and then radical polymerization while maintaining the above temperature for about 1 to 10 hours.

The monomer component may be an antistatic agent, a colorant, a filler, a UV absorber, a heat stabilizer, an antioxidant, or the like, depending on the intended use of the resulting copolymer. Can be included. In the present invention, the specific gravity is 1.1 or less, preferably 0.97 to 1.0 by the above method.
5, the light transmittance is 90% to 93%, the equilibrium water absorption is 0.3 to
0.9% by weight, the birefringence characteristic is a double ellipsometer (6
An optical disk substrate having a thickness of 20 nm or less can be obtained by measuring (33 nm). The crosslink density of the resin used for the optical disc substrate is preferably about 50% to 100%.
The thickness of the optical disk substrate may be any as long as it is within the above range of light transmittance, but a thickness of 0.01 to 1.0 cm is preferable. Further, the resin used for the present optical disk substrate is a cross-linked polymer having a penetration of 0.2 mm or less, preferably 0.1 mm or less at a load of 5 kg and a temperature of 100 ° C.

According to the present invention, there is provided an optical disk substrate having excellent transparency, low water absorption, low birefringence, and heat resistance. Furthermore, since it has a feature that it has a low specific gravity that conventional acrylic resins do not have, it is optimal for applications in which inorganic glass or conventional acrylic resins are used and weight reduction is required. Next, the present invention will be described based on examples, but the present invention is not limited thereto. The% shown below is% by weight unless otherwise specified.

[0011]

【Example】

Reference Example The dimer diol, trimer triol, and methacrylic ester compound of dimer diol / trimer triol = 7/3 used in the examples were prepared as follows. 72% methyl oleate and 18% methyl linoleate
Others Higher unsaturated fatty acid methyl ester containing 10% higher saturated fatty acid methyl is used as raw material, and activated clay (7%)
Was used as a catalyst to carry out a dimerization reaction at 220 ° C. for 7 hours. Unreacted fatty acid methyl ester fraction and isomerized fatty acid methyl ester fraction were removed from the product obtained by vacuum distillation (150 ° C / 0.1 torr), and the residue was subjected to molecular distillation (280 ° C / 0.1 torr). ) To obtain dimethyl dimer acid and trimethyl trimerate as a distillation residue. Next, dimethyl dimer acid alone, trimethyl trimer acid alone, and dimethyl dimer acid / trimethyl trimerate =
75/25 (weight ratio) mixture under high pressure hydrogen condition (220 kg / cm ² ) using copper-chromium catalyst 3% 2
Catalytic reduction is performed at 70 ° C. for 10 hours to obtain dimer diol,
Trimer triol and dimer diol / trimer triol = 75/25 were prepared. Next, dimer diol, trimer triol, and dimer diol /
Using trimertriol = 75/25 as a raw material, 1.05 equivalents of methacrylic acid to the -OH group of the higher polyhydric alcohol and 30% of cyclohexane as an azeotropic solvent to the raw higher polyhydric alcohol were added, and paratoluene was used as a catalyst. Sulfonic acid was added at 0.5% and the esterification reaction was carried out at 105 ° C. for 6 hours, followed by cooling and washing with water to remove cyclohexane, and a methacrylic esterified product of dimer diol (compound a),
Methacrylic ester of trimertriol (compound b), and dimerdiol / trimertriol = 7
A methacrylic ester compound (compound c) of 5/25 was obtained.

Example 1 Methacrylic ester compounds (compound a, compound b, compound c) alone or as a monomer copolymerizable therewith, the monomers d1 and d2 shown in Table 1 were used. Monomers d3 were mixed in the compositions shown in Table-2, and 0.5% perbutyl PB (manufactured by NOF Corporation) was added to the mixture as a radical polymerization initiator to prepare a composition for polymerization. did. Subsequently, nitrogen was passed through the composition for polymerization for 15 minutes, and the depth was 1.
It was poured into a glass mold having a cavity of 2 mm, 25 cm in width, and 30 cm in length. Next, the glass mold was heated from room temperature to 80 ° C. over 3 hours and then kept at 80 ° C. for 6 hours to carry out radical polymerization to obtain a synthetic resin optical disc substrate (the present invention products 1 to 7 and comparative examples). Example 1). In addition,
In Comparative Example 2 using polycarbonate, PC was produced by transesterification reaction of bisphenol A and diphenyl carbonate, and then a resin plate having a depth of 1.2 mm, a width of 25 cm, and a length of 30 cm was prepared by injection molding.

[0013]

[Table 1] Table-1 Copolymerization monomers ───────────────────────────────── Abbreviation Compound name Single Polymer d1 Methyl methacrylate monomer d2 t-Butyl methacrylate monomer d3 Divinylbenzene

The properties of the optical disk substrate of the present invention thus obtained were evaluated as follows. Specific gravity: AS
It was measured according to TM D792. Total light transmittance: Performed according to JIS K7105. Moisture absorption rate: Resin (15cmx15cmx1.2mm) 1 at 50 ℃
After drying with a weekly drier, it was immersed in water at 25 ° C. for 2 weeks, and the water content was calculated from the weight change. Birefringence property: The resin (1 cm x 1 cm x 1.2 mm) was measured at 633 nm using a double ellipsometer, and the results are shown in Table-2.

[0015]

[Table 2] Table-2 No. 1 2 3 4 5 Compound a 100 30 sets Compound b 70 Composition compound c 100 80 80 Ratio Monomer d1 10 (%) Monomer d2 10 Monomer d3 10 10 Specific gravity 0.973 0.981 0.977 0.990 0.980 Total light Transmittance (%) 91.5 91.8 91.7 91.6 92.0 Water absorption (%) 0.41 0.40 0.40 0.54 0.53 Birefringence (nm) <20 <20 <20 <20 <20

[0016]

[Table 3] Table-2 (continued) No. 6 7 Comparative Example 1 Comparative Example 2 sets Compound c 70 60 Monomer d1 100 ratio Monomer d2 15 20 (%) Monomer d3 15 20 Specific gravity 0.998 1.021 1.19 1.19 Total light transmittance (%) 91.3 91.7 92.1 90.1 Water absorption (%) 0.61 0.67 2.12 0.41 Birefringence characteristics (nm) <20 <20 <20 <60 As is clear from the results shown in Table-2, the optical disc substrate of the present invention (the present invention product 1 It can be seen that all of 7 to 7) have a specific gravity of 1.1 or less, a low water absorption rate, and good birefringence characteristics and total light transmittance.

Claims (1)

[Claims] 1. A dimer diol obtained by hydrogenating a dimer acid or a dimer acid ester, which is a dimer of a higher unsaturated fatty acid having 11 to 22 carbon atoms or a lower alcohol ester thereof, and an α represented by the general formula (I). By hydrogenating a trimer acid or trimer acid ester which is a trimer of an esterified product (A) with β-unsaturated carboxylic acids and / or a higher unsaturated fatty acid having 11 to 22 carbon atoms or a lower alcohol ester thereof Obtained by polymerizing an esterified product (B) of the trimertriol and an α, β-unsaturated carboxylic acid represented by the general formula (I), or a monomer (C An optical disc substrate made of a synthetic resin, characterized by comprising a polymer obtained by polymerizing a mixture (D) consisting of Embedded image R ₁ (R ₂ ) C═C (R ₃ ) COOR ₆ ... (I) (wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or C 1-6). Alkyl group, R ₆ is hydrogen or carbon number 1
Up to 8 alkyl groups are shown. )