JPS63213506A - Material for optical use - Google Patents

Abstract

PURPOSE:To obtain an optical material useful as videodisc, optical disc capable of erasing and rewriting, etc., having low double refraction, low water vapor absorption and excellent strength, by polymerizing a specific amount of a compound having a specific structure. CONSTITUTION:The aimed material having preferably <=150mn, especially <=100nm double refraction value and <=0.6%, especially <=0.2% saturated water absorption ratio obtained by polymerizing 100-5wt.% compound shown by formula I and/or formula II (R1 is H or 1-3C alkyl; R2 is 1-4C alkylene; R3-R5 are H or 1-3C alkyl; n is 1 or 2) and, if necessary, 0-95wt.% another monomer (e.g. methyl methacrylate, styrene, acrylonitrile, etc.) 3 or 4- Tricyclo[5.2.1.0<2.6>]decylmethyl methacrylate, etc., are used as the compound shown by formula I and/or formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a novel optical material used for video discs, compact discs, recordable optical discs, erasable/rewritable optical discs, and the like.

b. Prior Art In recent years, transparent resins have been used as various optical materials. In particular, today, when optical disks are attracting attention as information recording materials, the field of use of transparent resins, which are excellent in mass production, as substrate materials is expanding.

Such optical disk substrate materials include polycarbonate resin, polymethyl methacrylate resin, and polycyclohexyl methacrylate resin (Japanese Patent Application Laid-Open No. 58-12574).
No. 2), copolymers of alkyl methacrylate and methyl methacrylate, styrene or other monomers (JP-A-61-44610, JP-A-61-76509, JP-A-61-142546), bulky ester residues Polymers containing methacrylic acid esters having groups
No. 73705), etc. are known.

Problems to be Solved by the C0 Invention However, the transparent resins described above have drawbacks in any of the properties particularly required for optical disk materials, such as low birefringence, hygroscopicity, and strength.

For example, polystyrene resin and polycarbonate resin have high birefringence, so when reading recorded information by irradiating an optical disk with a laser beam, reading errors due to the birefringence of the laser beam increase.

Furthermore, since polymethyl methacrylate resin has high hygroscopicity, it deforms due to moisture absorption, increasing reading errors, and also induces deterioration of the recording film due to moisture absorption.

Furthermore, polycyclohexyl methacrylate resin is
Although hygroscopicity is improved, the glass transition temperature is extremely low, resulting in low heat resistance.

Furthermore, among copolymers of cyclohexyl methacrylate and methyl methacrylate or styrene, for example, copolymers of cyclohexyl methacrylate and methyl methacrylate have high heat resistance but low hygroscopicity; Polymers have high birefringence (optical properties are impaired).

Still another method is to use a polymer or copolymer using a methacrylic acid ester derivative having a bulky hydrophobic group, as shown by the general formula (C) (in which R represents hydrogen or a methyl group). A method of reducing water absorption (Japanese Patent Application Laid-open No. 73705/1982) has also been proposed, but the polymer having the structure of general formula (C) has extremely low strength (especially increased brittleness).

As described above, there has been no optical resin that has low birefringence, low moisture absorption, and excellent strength.

Means for Solving the d0 Problem The inventors of the present invention sought to obtain a new resin that satisfies the above characteristics (as a result of intensive research, a polymer formed by polymerizing a specific amount of a compound having a specific structure was found to be The inventors have discovered that the problems can be solved and have arrived at the present invention.

That is, the present invention provides general formula (A) and/or general formula (B) (wherein R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms,
RX is an alkylene group having 1 to 4 carbon atoms, R3-R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and n is 1 or 2) 100 to 5% by weight of the compound and as necessary 0 to 95% by weight of other monomers copolymerizable with the compound
The object of the present invention is to provide an optical material made of a polymer obtained by polymerizing.

The polymer according to the present invention has general formula (A) and/or (
A homopolymer of the monomer represented by B), a copolymer of the monomer represented by the general formula (A) and/or (B), or a monopolymer of the monomer represented by the general formula (A) and/or (B) It is a copolymer of a monomer and another monomer that can be copolymerized with the compound.

The above polymer preferably has a birefringence value of 150 ns or less and a saturated water absorption of 1.5% or less, more preferably a birefringence value of 100 n- or less and a saturated water absorption of 1.0.
% or less, and particularly preferably has a saturated water absorption of 0.6% or less, more preferably 0.4% or less, especially 0.2% or less.

Examples of the compound represented by the general formula (A) or (B) include 3- or 4-tricyclo(5,2,1,0''
') Decyl methyl methacrylate, 2-(3 or 4
-tricyclo(5,2,1,0'')decylethyl methacrylate, 3-(3 or 4-tricyclo(5,2
,1,0'')decylpropyl methacrylate, 8 or 9-tricyclo(5,2,1,0''6)decylmethyl methacrylate, 2-(8 or 9-tricyclo(5
,2,1,0"") decylethyl methacrylate, 3
-(8 or 9-tricyclo(5,2,1,0''-')
Decylpropyl methacrylate, 5 Matah 6-te) Lasik O (9,2,1,13°9.08°10) Pentadecylmethyl methacrylate, 2-(5 or 6-tetracyclo(9,2,1,1'') , 0” ”) pentadecyl ethyl methacrylate, 3-(5 or 6-tetracyclo(9,2,1,13・9.9!+I@) pentadecylpropyl methacrylate, 12 or 13-tetracyclo(9,2, 1,13°1.Qzllll) pentadecyl methyl methacrylate, 2-(12 or 13-tetracyclo(9,2,1,1'',02.10) pentadecylethyl methacrylate, 3-(12 or 13
-tetracyclo(9,2,1,1'',0'''')
Mention may be made of pentadecylprobyl methacrylate. Preferably, in the above general formula (A) or (B), a compound having hydrogen or a methyl group as R1, an alkylene group having 1 to 2 carbon atoms as R2, and hydrogen or an alkyl group having 1 to 2 carbon atoms as R1 to Rs. Especially preferably, R3 is a methyl group, R1 is a methylene group,
It is a compound having hydrogen or a methyl group as R3-R2.

Other monomers copolymerizable with the compound represented by the above general formula (A) and/or (B) include (meth)acrylic acid compounds, aromatic vinyl compounds, vinyl cyanide compounds, and unsaturated dibasic compounds. Mention may be made of acids and their derivatives, unsaturated fatty acids and their derivatives.

(Meth)acrylic acid compounds include methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid 2
- Acrylic acid alkyl esters such as ethylhexyl, acrylic acid cycloalkyl esters such as cyclohexyl acrylate, methylcyclohexyl acrylate, bornyl acrylate, and adamantyl acrylate, and aromatic acrylic acids such as phenyl acrylate, benzyl acrylate, and naphthyl acrylate. esters, acrylic acid halogen-substituted aromatic esters such as fluorophenyl acrylate and chlorophenyl acrylate, acrylic acid halogenated alkyl esters such as fluoromethyl acrylate, chloroethyl acrylate, and bromoethyl acrylate, hydroxyalkyl acrylate ester, glycidyl acrylate , methacrylic acid alkyl esters such as acrylic acid polyethylene glycol ester, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; methacrylic acid cycloalkyl esters such as cyclohexyl methacrylate, bornyl methacrylate, and adamantyl methacrylate; Aromatic methacrylic esters such as phenyl methacrylate, benzyl methacrylate, and naphthyl methacrylate; halogen-substituted aromatic esters of methacrylic acid such as fluorophenyl methacrylate and chlorophenyl methacrylate; fluoromethyl methacrylate, chloroethyl methacrylate, bromoethyl methacrylate, etc. Examples include methacrylic acid esters such as methacrylic acid halogenated alkyl esters, methacrylic acid hydroxyalkyl esters, glycidyl methacrylate, and polyethylene glycol methacrylate esters, and α-substituted acrylic esters such as α-phenylacrylic acid esters.

Examples of the aromatic vinyl compound include styrene or α-substituted styrenes such as α-methylstyrene and α-ethylstyrene, and nuclear-substituted styrenes such as fluorostyrene, chlorostyrene, bromostyrene, methylstyrene, and butylstyrene.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylate trile.

Examples of unsaturated dibasic acids and their derivatives include N-substituted maleimides such as N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide, maleic acid, maleic anhydride, and fumaric acid. Examples include acids.

Unsaturated fatty acids and their derivatives include acrylamides and methacrylamides such as acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dimethylmethacrylamide, and N,N-diethylmethacrylamide. , calcium acrylate, calcium methacrylate, barium acrylate, barium methacrylate, lead acrylate, lead methacrylate, tin acrylate, tin methacrylate, zinc acrylate, zinc methacrylate, and other metal salts of acrylic acid and methacrylic acid. , acrylic acid, metal salts of methacrylic acid, acrylic acid, methacrylic acid, and the like.

Among these monomers, methyl methacrylate, styrene, and acrylonitrile are preferably used because they can improve strength.

In the present invention, the general formula (A) and/or (B
) and other monomers copolymerizable with the compound are 10010 to 5/95, preferably 80
/20 to 20/80, more preferably 70/30 to 3
It is 0/70. If the number of compounds represented by formula (A) and/or (B) is less than 5, the water absorption rate increases, which is not preferable.

As a method for producing the polymer used in the present invention, known methods such as radical polymerization, ionic polymerization, and coordination polymerization can be applied.For example, in the presence of a polymerization initiator, bulk polymerization, solution polymerization, suspension polymerization, It can be produced by methods such as emulsion polymerization, but
Since the polymer used in the present invention is used as an optical material, bulk polymerization or solution polymerization is preferable since it is necessary to avoid contamination with impurities.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, and 1,1-di-t-butylperoxy. Oxy-3,
Organic peroxides such as 3,5-trimethylcyclohexane, azo compounds such as azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, and azodibenzoyl , water-soluble catalysts such as potassium persulfate and ammonium persulfate, and redonx catalysts using a combination of peroxide or persulfate and a reducing agent, which can be used in ordinary radical polymerization, can be used.

The polymerization catalyst is preferably used in an amount of 0.01 to 10% by weight based on the total amount of monomers.

As the polymerization regulator, mercaptan compounds, thioglycol, carbon tetrabromide, etc. can be used to control the molecular weight.

The polymerization temperature is 0 to 200°C, preferably 50 to 120°C.

Solvents for solution polymerization include benzene, toluene,
Xylene, cyclohexane, methyl ethyl ketone, ethyl acetate, and dichloroethylene can be used.

Suspension polymerization is carried out in an aqueous medium and a suspending agent is added.

As this suspending agent, sparingly soluble inorganic substances such as polyvinyl alcohol, methyl cellulose, and polyacrylamide can be used. Water-soluble polymer is 0 based on the total amount of monomers.
．． It is preferable to use 0.05 to 0.5% by weight.

The molecular weight of the polymer used in the present invention is not particularly limited, but
In order to create a resin with heat resistance and mechanical properties above a certain level,
Weight average molecular weight (polystyrene equivalent) is 10.000~
The molecular weight of the polymer is preferably in the range of 1,000,000, more preferably 30,000 to 700,000, particularly preferably so, ooo to 500,000. If the molecular weight of the polymer is less than 10,000, the strength is insufficient. Molding is difficult, and if it exceeds 1,000.000, the fluidity properties deteriorate and molding such as injection molding and extrusion molding becomes difficult, which is not preferable.

Further, the intrinsic viscosity of the polymer used in the present invention (30°C, in toluene) is preferably 0.1 to 5 a/g, more preferably 0.2 to 3 a/g, particularly preferably 0.3 to 2 a/g.
The intrinsic viscosity of the 0 polymer (30°C, in toluene) is 0
．． If it is less than 1 a/g, it will be difficult to mold due to insufficient strength, and if it exceeds 5 a/g, the flow characteristics will deteriorate and molding such as injection molding and extrusion molding will be difficult, which is not preferable.

In addition, the polymer used in the present invention can be used as long as it does not lose its transparency.
Random copolymers, alternating copolymers, graft copolymers,
There are no particular limitations on the form of the block copolymer, polymer blend, etc.

The polymer used in the present invention includes anti-acid agents such as phenol-based, phosphite-based, and thioether-based, aliphatic alcohol, and fatty acid for the purpose of improving antioxidant properties, thermal stability, moldability, processability, etc. Addition of mold release agents such as esters, phthalate esters, triglycerides, fluorine surfactants, higher fatty acid metal salts, other lubricants, plasticizers, antistatic agents, ultraviolet absorbers, flame retardants, heavy metal deactivators, etc. can do.

Various known molding methods can be applied to the method of molding the optical material of the present invention. That is, injection molding, compression molding, extrusion molding, etc. are used. In the casting method, a molded article can also be obtained by partially polymerizing and then injecting into a mold to complete the polymerization.

The optical material of the present invention can be coated on the surface of the molded product using a vacuum evaporation method.
Coating with inorganic compounds by sputtering method, ion blating method, etc., hard coating the surface of molded products with organic silicon compounds such as silane coupling agents, vinyl monomers, melamine resins, epoxy resins, fluorine resins, silicone resins, etc. By doing so, heat resistance, optical properties, chemical resistance, abrasion resistance, moisture permeability, etc. can be improved.

The optical material of the present invention is suitable as a substrate material for lenses for general cameras, video cameras, telescopes, laser beams, etc., optical video disks, audio disks, document file disks, memory disks, etc.

e. Examples Next, examples of the present invention will be shown, in which 3 or 4-tricyclo(5,2,1,0''°6]decylmethyl methacrylate was converted into compound (1), 5- or 6-tetracyclo[9
゜2.1.1'°9.0! +16) Pentadecyl methyl methacrylate was used as compound (2).

Example 1 After purging the inside of a separable flask with an internal volume of 300+ sl equipped with a reflux condenser and a stirrer with nitrogen, 20 g of toluene 1 Compound (1) (3-tricyclo(5,2
゜1.0''°' Mixture of 3-decyl methyl methacrylate and 4-tricyclo(5,2,1,0''-6]decyl methyl methacrylate) 50 g and azobisisobutyronitrile 31a+g were added, and the reaction mixture was stirred. At the same time, the mixture was heated in a 70°C water bath. After 8 hours, the reaction mixture was added to a large amount of methanol, and the precipitated polymer was dried by heating under reduced pressure.

The obtained polymer had a polystyrene equivalent molecular weight of 4 measured by GPC (gel permini-silane chromatography).
．． It was a solid of I x 10'. This polymer was crushed into powder, and a test piece (40 mm long x 1 mm wide, 1.2 m thick) was prepared using a 0.1 ounce injection molding machine.

Examples 2 to 7 Example 1 except that the monomers were changed to those shown in Table 1.
Each polymer was obtained in the same manner as above.

Example 8 A polymer was obtained in the same manner as in Example 1, except that Compound (5) was used in which R1 was replaced with hydrogen in Compound (1) used in Example 1.

Example 9 In the compound (1) of Example 1, R2 is an ethylene group (
A polymer was obtained in the same manner as in Example 1, except that compound (6) was used instead of (Cut Cut).

Comparative Examples 1 to 3 The monomer was 8-tricyclo(5,2,1,0"°6]decyl methacrylate compound (3) or 12-tetracyclo[9°2.1.1"', 0t1o) pentadecyl methacrylate Each polymer was obtained in the same manner as in Example 1 except that the compound was replaced with (compound (4)).

Table 1 shows the results of measuring the intrinsic viscosity, birefringence value, saturated water absorption, and brittleness of each polymer obtained in Examples 1 to 9 and Comparative Examples 1 to 3.

The intrinsic viscosity was determined by measuring the relative viscosity of a 0.5 g/d1 toluene solution of the polymer at 30° C. and using the following formula.

The birefringence value was measured with an ellipsometer using a sample plate formed by injection molding.

The saturated water absorption rate was determined by immersing a sample in water, reaching an equilibrium state, and then measuring the weight of the sample that had absorbed water. This sample was heated to 200° C. under a stream of dry nitrogen, and the amount of released water was determined by the Carl Fifsi method. The saturated water absorption rate is calculated from the following formula.

Brittleness is determined by comparing the relative appearance of scratches made on the surface of injection molded samples with a cutter knife.
Items with "chips" are indicated as "×".

As is clear from the above examples, polymethyl methacrylate has a high water absorption rate, whereas Examples 1 to 4, which are optical materials of the present invention, all show low values. Compounds (6) and (7) (Comparative Example 2.3) had small water absorption values but were brittle and lacked mechanical strength. No brittleness was observed in the polymers of Examples 1-4.

f6 Effects of the Invention The optical material of the present invention exhibits excellent properties such as low birefringence, low water absorption, and improved brittleness.
Its practical value is greater than that of conventional optical materials.

Procedure Written by the principal author (self-motivated) April 1, 1988 1. Indication of the case 1988 Patent Application No. 46352 2. Name of the invention Optical material 3. Person making the amendment Relationship to the case Patent applicant Name (417) Japan Synthetic Rubber Co., Ltd. 4, Agent
107 Address: 3-2-3-5 Akasaka, Minato-ku, Tokyo, "Detailed Description of the Invention" column of the specification to be amended.

Contents of amendment (1) General formula (C) in the fourth line from the bottom of page 4 of the specification is corrected as follows.

Note (2) In the third line from the bottom of the same book, "hydrophobic group" is corrected to "hydrophobic group."

(3) Same book, page 7, lines 1θ, 12, 13~
Line 14.

“Tetracyclo” in lines 15, 17 and 19
is corrected to "Pentacyclo".

(4 Same book, same page, lines 10, 12, 14, 16, 18, and 19 r (9, 2, 1, 1'
1.0t'16) J to r (9, 2, 1, 1'°9.
08°I@, Q4°8〕.

(5) "Page 16, line 7 and page 17, line 18 of the same book"
r (9,2,
1,1'・9. Correct it as Ot・”, 0'゛”) j.

Claims (4)

[Claims] (1) General formula (A) and/or general formula (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (B) (In the formula, R_1 is hydrogen or Alkyl group having 1 to 3 carbon atoms, R_2 is an alkylene group having 1 to 4 carbon atoms, R_3 to R_
5 is hydrogen or an alkyl group having 1 to 3 carbon atoms, n is 1 or 2) 100 to 5% by weight of a compound represented by the formula (5 is hydrogen or an alkyl group having 1 to 3 carbon atoms) and, if necessary, 0 to 95% of other monomers copolymerizable with the compound. weight%
An optical material made of a polymer obtained by polymerizing. (2) The optical material according to claim (1), wherein the polymer has a birefringence value of 150 nm or less and a saturated water absorption of 0.6% or less. (3) The optical material according to claim (1), wherein the polymer has a birefringence value of 100 nm or less and a saturated water absorption of 0.4% or less. (4) The optical material according to claim (1), wherein the polymer has a birefringence value of 100 nm or less and a saturated water absorption of 0.2% or less.