JPS63243114A - Optical material - Google Patents

Abstract

PURPOSE:To obtain the titled material formula excellent optical characteristics, heat resistance, low water vapor absorption, high mechanical strength and improved moldability, comprising a novel copolymer of a specific compound and methacrylic acid methyl ester or ethyl ester. CONSTITUTION:35-65pts.wt. compound shown by formula I and/or compound shown by formula II is copolymerized with 35-65pts.wt. methacrylic acid methyl ester or ethyl ester by bulk polymerization or solution polymerization to give the aimed material. Methacrylic acid tricyclo[5.2.1.0<2.6>-deca-8-yl-(methacrylic acid tricyclodecyl) is preferable as the compound shown by formula I. The compound shown by formula II, for example, is obtained by selectively hydrogenating double bond of norbornene ring of dicyclopentadiene, epoxidating double bond at the 5-membered ring side, further successively reducing and esterifying the resulting substance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical disc suitable for use as a material for video discs, compact discs, recordable optical discs, recordable/erasable/playable optical discs, plastic lenses, etc. It's about materials.

[Conventional technology]

In recent years, transparent resins have come to be used as a variety of optical materials, and optical disks in particular have attracted attention as information recording materials, and the use of transparent resins, which are easily mass-produced, as substrate materials for them has been studied. ing.

Conventionally, substrate materials for such optical discs include polycarbonate resins, polymethyl methacrylate resins, polycyclohexyl methacrylate resins, copolymer resins of alkyl methacrylate and methyl methacrylate, styrene or other monomers, and bulky ester groups. Polymers containing methacrylic acid esters having the following are known.

[Problem that the invention seeks to solve]

The above-mentioned optical materials do not satisfy all of the requirements of low birefringence, low hygroscopicity, and mechanical strength particularly as substrate materials for optical discs.

For example, polystyrene resin or polycarbonate resin with high birefringence causes many errors when reproducing information using laser light, and polymethyl methacrylate resin with high hygroscopicity causes many errors when reproducing information because it deforms due to moisture absorption. At the same time, there is a large risk that the recording film will deteriorate due to moisture absorption. Polycyclohexyl methacrylate resin also has the problem of poor heat resistance due to its low glass transition point, apart from its hygroscopicity. Copolymers with methyl methacrylate or styrene have improved heat resistance, but copolymers with methyl methacrylate have high hygroscopicity, while copolymers with styrene have increased birefringence and poor optical properties. becomes inferior.

Further, an optical material made of a polymer or copolymer using a methacrylic acid ester derivative having a bulky hydrophobic group has been proposed in JP-A-61-73705.

These polymers or copolymers are preferable in that they generally have good heat resistance and optical properties, but they have low mechanical strength, high viscosity when melted, and poor moldability. Depending on the composition, it may have poor hygroscopicity,
There is also the problem that optical properties are also impaired.

[Means for solving problems]

The present invention is made of a new copolymer that has excellent optical properties and heat resistance, low moisture absorption, high mechanical strength, and low viscosity when melted, resulting in good moldability. The present invention provides an optical material having the following properties. That is, the optical material of the present invention comprises a compound represented by the following general formula (I) and/or a compound represented by the general formula (II) 35
It is characterized by being composed of a copolymer obtained by copolymerizing ~65 parts by weight with 35 to 65 parts by weight of methyl ester or ethyl ester of methacrylic acid.

General formula (I) General formula (II) (wherein, R represents a hydrogen atom or a methyl group)
) and/or 35 to 65 parts by weight of a compound represented by general formula (n) and 65 to 35 parts by weight of a lower alkyl ester of methacrylic acid whose alkyl group has 2 or less carbon atoms. It is a copolymer with parts.

The above copolymer preferably has a saturated water absorption of 1.8% or less, an Atsube's number of 45 or more, and a glass transition point of 100°C or more.Furthermore, the saturated water absorption is 1.2%.
It is preferably at most 0.6%, especially at most 0.6%, the Abbé number is preferably at least 50, especially at least 55, and the glass transition point is preferably at least 100°C.

The compound represented by the general formula (I) is, for example, JP-A-61
It can be manufactured by the method described in JP-A-73705. In addition, the compound represented by the general formula (lr) is obtained by selectively hydrogenating the double bond of the norbornene ring of dicyclopentadiene, epoxidizing the double bond on the five-membered ring side, and further reducing the precursor. It can be synthesized by converting it into an alcohol and esterifying it with (meth)acrylic acid.

-a Specific examples of the compound represented by formula (I) include tricyclo[5,2,1,0''h]-dec-8-yl methacrylate (tricyclodecyl methacrylate), tricyclo[5 ,2,1,0”] -]tekar8
-yl (tricyclodecyl acrylate) and the like can be preferably used in the present invention.

The monomer copolymerized with the compound represented by the above general formula (I) and/or the compound represented by the general formula (n) is one or two selected from methacrylic acid methyl ester and methacrylic acid ethyl ester. It is.

The proportion of the lower alkyl ester of methacrylic acid is 35 to 65% by weight or less, particularly preferably in the range of 40 to 60% by weight, based on the total amount of monomers, and this proportion is preferably 65% by weight or less. If it exceeds this, the copolymer finally obtained will have high water absorption and low heat resistance. If this proportion is less than 35% by weight, not only will it be difficult to obtain a copolymer with high strength, but also the melt viscosity of the obtained copolymer will be high, making it impossible to improve moldability.

The lower alkyl ester of methacrylic acid described above can also be used in the form of a prepolymer, and in this case, it is expected that the ultimately obtained copolymer will have excellent impact resistance.

In addition, monomers other than the lower alkyl ester of methacrylic acid that can be copolymerized with the compound represented by the general formula ([) and/or the compound represented by the general formula (n) are required. It can be used as a monomer component depending on the situation.

Examples of such other monomers include unsaturated fatty acid esters, aromatic vinyl compounds, vinyl cyanide compounds, unsaturated dibasic acids or derivatives thereof, and unsaturated fatty acids or derivatives thereof.

Examples of unsaturated fatty acid esters include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, cyclohexyl acrylate, methylcyclohexyl acrylate, bornyl acrylate, isobornyl acrylate, and acrylic acid. Acrylic acid cycloalkyl esters such as adamantyl, phenyl acrylate, benzyl acrylate,
acrylic acid aromatic esters, such as naphthyl acrylate;
Acrylic acid substituted aromatic esters such as fluorophenyl acrylate, chlorophenyl acrylate, bromophenyl acrylate, fluorobenzyl acrylate, chlorobenzyl acrylate, bromobenzyl acrylate, fluoromethyl acrylate, fluoroethyl acrylate, chloroethyl acrylate , acrylic acid halogenated alkyl esters such as bromoethyl acrylate, acrylic acid hydroxyalkyl esters, glycidyl acrylates, acrylic acid ethylene glycol esters, acrylic acid polyethylene glycol esters, acrylic acid alkylaminoalkyl esters, acrylic acid cyanoalkyl esters, etc. Acids, esters, methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl meccrylate, methylcyclohexyl methacrylate, bornyl methacrylate, isobornyl methacrylate, adamantyl methacrylate, etc. Aromatic methacrylic esters such as cycloalkyl methacrylate, phenyl methacrylate, benzyl methacrylate, naphthyl methacrylate, fluorophenyl methacrylate, chlorophenyl methacrylate, bromophenyl methacrylate, fluorobenzyl methacrylate, chlorobenzyl methacrylate, methacrylate Methacrylic acid substituted aromatic esters such as bromobenzyl methacrylate, halogenated alkyl methacrylate esters such as fluoromethyl methacrylate, fluoroethyl methacrylate, chloroethyl methacrylate, bromoethyl methacrylate, hydroxyalkyl methacrylate ester, glycidyl methacrylate, methacrylic acid Methacrylic esters such as ethylene glycol ester, polyethylene glycol methacrylate, alkylaminoalkyl methacrylate, cyanoalkyl methacrylate, α-fluoroacrylic ester, α-chloroacrylic ester, α-cyanoacrylic ester, etc. Examples include α-substituted acrylic esters.

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

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile.

Unsaturated dibasic acids and their derivatives include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N-methoxy Phenylmaleimide, N-
Examples include N-substituted maleimides such as carboxyphenylmaleimide, maleic acid, maleic anhydride, and fumaric acid.

Examples of unsaturated fatty acids and their derivatives include acrylamide, methacrylamide, N-dimethylacrylamide,
Acrylamides or methacrylamides such as N-diethylacrylamide, N-dimethylmethacrylamide, N-diethylmethacrylamide, calcium acrylate, calcium methacrylate, barium acrylate,
Examples include metal salts of acrylic acid or methacrylic acid such as barium methacrylate, lead acrylate, lead methacrylate, tin acrylate, tin methacrylate, zinc acrylate, zinc methacrylate, acrylic acid, methacrylic acid, etc. Furthermore, 2 (in the formula, R is a hydrogen atom or a methyl group, R″ is a methylene group, and n is O or 1.)
Examples include compounds represented by: These can be used alone or in combination of two or more.

Among the above compounds, preferred are non-aromatic maleimides, tricyclopentadiene (meth)acrylates, etc., more preferred are non-aromatic maleimides, and cyclohexylmaleimide is particularly preferred.

The method for producing the copolymer according to the present invention includes:
Radical polymerization method and other known methods can be applied, such as bulk polymerization method in the presence of a polymerization initiator,
Methods such as solution polymerization and suspension polymerization are used, but it is preferable to use bulk polymerization or solution polymerization, especially since contamination with impurities should be avoided especially for optical materials.

As the initiator used in the polymerization reaction, those used in ordinary radical polymerization can be used as they are.

Specific examples include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-di-l-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 Examples include water-soluble catalysts typified by potassium persulfate and ammonium persulfate, and redox catalysts using a combination of a peroxide or a persulfate and a reducing agent. These initiators are preferably used in an amount of 0.01 to 10% by weight based on the total amount of monomers to be polymerized. As a polymerization regulator, a molecule M regulator such as a mercaptan compound, thioglycol, carbon tetrabromide, or α-methylstyrene dimer is used as necessary.

The polymerization temperature is appropriately selected within the range of 0 to 200°C, but 50 to 120°C is particularly preferred.

As a solvent in the case of the solution polymerization method, Hensen, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, dichloroethylene, etc. can be used.

When using the suspension polymerization method, a suspending agent and, if necessary, a suspending aid are added to the aqueous medium. Specific examples of suspending agents include water-soluble polymeric substances such as polyvinyl alcohol, methylcellulose, and polyacrylamide, and sparingly soluble polymers such as calcium phosphate and magnesium pyrophosphate.
In the case of water-soluble polymeric substances, the proportion is 0.03 to 1% by weight based on the total amount of monomers, and in the case of sparingly soluble inorganic substances, the proportion is based on the total amount of monomers. te 0.05~
It is preferable to use it in a proportion of 0.5% by weight, and examples of suspension aids include anionic surfactants such as sodium dodecylbenzenesulfonate. When the substance is used, it is preferable to use a suspension aid in combination, and the suspension aid is preferably used in a proportion of 0.001 to 0.02% by weight based on the total amount of monomers.

The copolymer according to the present invention is not particularly limited in its molecular weight, but from the viewpoint of obtaining excellent heat resistance and mechanical strength, the copolymer has a weight average molecular weight (polystyrene equivalent) of 1.
It is preferably in the range of 0,000 to 1,000,000, and within this range, good moldability can be obtained, especially when used as a molding material. Further, from the viewpoint of strength, it is preferable that the intrinsic viscosity η of the copolymer is Q, 7aJ/g or more.

Further, it is preferable that the copolymer according to the present invention has an excellent low hygroscopicity when the ratio of carbon atoms in the molecule according to polymer elemental analysis is 60% by weight or more. It is preferable that the water absorption rate is 0.3% or less. Mechanical strength is, for example, tensile strength of 600k.
g/cm" or more is preferable.

Furthermore, the copolymer according to the present invention may be in the form of a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer, or a blend copolymer, as long as transparency is not impaired. .

When the copolymer according to the present invention is used, antioxidants such as phenolics, phosphites, and thioethers, aliphatic Addition of mold release agents such as alcohol, fatty acid esters, phthalate esters, triglycerides, fluorine surfactants, higher fatty acid metal salts, other lubricants, plasticizers, antistatic agents, ultraviolet absorbers, heavy metal deactivators, etc. agents can be added.

Since the optical material of the present invention has good moldability, it can be made into an optical material by applying various known molding methods. That is, injection molding, compression molding, extrusion molding, etc. can be used. In the case of a casting method, a partially polymerized monomer composition may be injected into a mold to complete the polymerization.

The optical material according to the present invention has a vacuum evaporation method,
Heat resistance is achieved by hard coating with inorganic compounds, organic silicon compounds such as silane coupling agents, vinyl monomers, melamine resins, epoxy resins, fluorine resins, silicone resins, etc. using methods such as sputtering and ion blating. , optical properties, chemical resistance,
Abrasion resistance, moisture permeability, etc. can be improved.

Applications of the optical material of the present invention are not particularly limited, and can be used over a wide range, for example,
It can be suitably used for lenses such as general camera lenses, video camera lenses, telescope lenses, and laser beam lenses, optical video discs, audio discs, document file discs, memory discs, and the like.

〔effect〕

The optical material of the present invention comprises a compound represented by general formula (I) and/or a compound represented by general formula (II>),
Since it is made of a copolymer with a specific lower alkyl ester of methacrylic acid, it has excellent optical properties and is a compound represented by the general formula (I) and/or a compound represented by the general formula (n). It has excellent optical properties and heat resistance, low moisture absorption, high mechanical strength, low viscosity when melted, and good moldability.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 Tricyclo[5,2,1,0''-']-decar-8-yl methacrylate (tricyclodecyl methacrylate) (compound (I))...50 parts by weight Methyl methacrylate...50 weight Part azobisisobutyronitrile ... 0.02 parts by weight Toluene
...50 parts by weight or more of a substance in a capacity lj! equipped with a reflux condenser and a stirrer! The copolymer was placed in a flask, heated to 80° C. with stirring, and reacted for 8 hours to obtain a copolymer.

This copolymer had a polystyrene equivalent weight average molecular weight of about 50,000 as measured by gel vermini-silane chromatography.

The obtained polymer was pulverized and then a test sample was prepared using a 0.1 ounce injection molding machine.

Example 2 Tricyclo[5,2,1,0""h]-decar-8-yl methacrylate (tricyclodecyl methacrylate) (compound (I))...60 parts by weight Methyl methacrylate...40 weight Part azobisisobutyronitrile ... 0.02 parts by weight Toluene
...Using 50 parts by weight or more of a substance,
A copolymer was obtained by a method similar to Example 1.

This copolymer had a polystyrene equivalent weight average molecular weight of about 50,000 as measured by gel permeation chromatography.

The obtained polymer was pulverized and then a test sample was prepared using a 0.1 ounce injection molding machine.

Example 3 Tricyclo[5,2,1,0''·1]-dec-8-yl methacrylate (tricyclodecyl methacrylate) (compound (I))...40 Parts by weight Methyl methacrylate...60 Part by weight Azobisisobutyronitrile...0.02 part by weight, Toluene
... A copolymer was obtained by a method similar to Example 1 using 50 parts by weight or more of the substance.

This copolymer had a polystyrene equivalent weight average molecular weight of about 60,000 as measured by gel permini-silane chromatography.

The obtained polymer was pulverized and then a test sample was prepared using a 0.1 ounce injection molding machine.

Examples 4 to 6 According to the conditions shown in Table 1, tricyclo[5,2,1,0'''h]-dec-8-yl(tricyclodecyl acrylate) ( Compound(
2)), and by a method similar to Example 1, a total of 3
A seed copolymer was obtained from which test samples were prepared.

Comparative Example 1 Tricyclo[5,2,1,0''1-deca-methacrylate
8-yl (tricyclodecyl methacrylate) (compound (
I))...78 parts by weight Methyl methacrylate...22 parts by weight Azobisisobutyronitrile...0.02 parts by weight Toluene
...A copolymer was obtained using a method similar to Example 1 using 50 parts by weight or more of the substance, and a test sample was prepared from this copolymer.

Comparative Example 2 Tricyclo[5,2,1,0''·6]-dec-8-yl methacrylate (tricyclodecyl methacrylate) (compound (I))...25 Parts by weight Methyl methacrylate...75 Part by weight Azobisisobutyronitrile ... 0.02 part by weight Toluene
...Using 50 parts by weight or more of a substance,
A copolymer was obtained by a method similar to Example 1, and a test sample was prepared from this copolymer.

Using the test samples of the copolymers obtained in the above Examples and Comparative Examples, the intrinsic viscosity, birefringence value, saturated water absorption, surface brittleness, melt flow rate (MFR), and tensile strength were determined as follows. I asked for it like this.

4th round! A toluene solution with a concentration of 0.5 g/dl was prepared from a sample, and its relative viscosity η at 30° C. was measured and calculated using the following formula.

Measured by ellipsometer.

A silver dish water absorption sample was immersed in water to allow the sample to absorb water, and the weight w of the sample after reaching an equilibrium state was measured, and then the sample was heated to 200 ° C. under a stream of dry nitrogen. The amount of water released by this W! was determined by the Karl Fischer method, and the saturated water absorption rate was calculated by the following formula.

W.

Saturated water absorption rate = -x 100 (%) W, -WZ If the surface of the Omotesato Hokuen sample is scratched with a licutter knife, and the resulting scratches are only traces of the passage of the knife, it is considered "good". If in addition to traces of passage, there are minute cracks in the surrounding area, it is determined to be ``defective J.''

Melt flow rate 01FR) Temperature 240'C according to ASTM D 1238 (7) method
The weight of resin flowing out in 10 minutes under a load of 10 kg was measured.

The test results are shown in Table 1.

As is clear from Table 1, the copolymer of the present invention has excellent optical properties and heat resistance, low hygroscopicity, high mechanical strength, and An optical material having low viscosity and good moldability can be provided.

Claims (1)

[Scope of Claims] 1) 35 to 65 parts by weight of a compound represented by the following general formula (I) and/or a compound represented by general formula (II) and 35 to 65 parts by weight of methyl ester or ethyl ester of methacrylic acid. An optical material comprising a copolymer obtained by copolymerizing. General formula (I) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (II) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a hydrogen atom or a methyl group.)