JPH0643461B2 - Method for producing optical resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an optical resin composition suitable for molding an optical element such as an optical lens, an information transmitter and an information recording medium.

(Prior Art) In recent years, plastic optical elements have become popular due to their light weight and mass productivity, but in particular, based on advances in molding technology such as injection molding and compression molding, cameras, copiers, laser optics, etc. Applications to optical lenses for devices and the like, disk boards in the form of information recording media using laser light, optical fibers, information transmitters such as connectors, and optical waveguide circuits are expanding.

Examples of the resin for such an optical element include polystyrene resin, polycarbonate resin, polymethylmethacrylate resin, polycyclohexylmethacrylate resin (JP-A-58-125742), cyclohexylmethacrylate and methylmethacrylate, styrene or other monomers. Copolymer (JP-A-58-162614)
JP-A-58-5318, JP-A-58-11321
No. 4) is known.

However, these resins have major drawbacks in any of optical dispersibility, hygroscopicity and heat resistance.

For example, an optical lens has high refractive index and low dispersion optical properties, low surface accuracy due to moisture absorption deformation (in other words, low hygroscopicity), heat resistance and precision moldability. Although particularly required, polystyrene resin, polycarbonate resin, etc. have large dispersion (optical dispersion:
Since the Abbé number is 30 to 31), there is a problem that chromatic aberration is large, and the polymethylmethacrylate resin has a large hygroscopic property, and there is a problem that the surface accuracy due to hygroscopic deformation is large.

Also, video discs, audio discs that read (or write) information using laser light,
In information recording media such as recording / reproducing discs and recording / reproducing erasing discs, low birefringence, low hygroscopicity and heat resistance are particularly required, but polystyrene resins, polycarbonate resins, etc. However, the polymethylmethacrylate resin has a problem in that the surface precision of the disk is reduced due to the deformation due to moisture absorption, and there is a problem in that an error occurs during reproduction.

However, among the above resins, the polymethylmethacrylate resin has excellent optical properties except for the drawback that it is easily deformed by moisture absorption, and can be said to be the most excellent resin in this respect.

Therefore, recently, various studies have been made on the development of a resin having an optical property equivalent to that of a polymethylmethacrylate resin and an improved hygroscopic property.

(Problems to be Solved by the Invention) The present inventor conducted various studies in order to develop a resin material having low optical dispersibility and low hygroscopicity. First, a rigid structure was formed by the alcohol component of the ester. It was found that the (co) polymer of a methacrylate having an alicyclic hydrocarbon group has the above conditions, and its application as an optical element molding material was investigated.

However, these (co) polymers of methacrylates having alicyclic hydrocarbon groups generate trace substances that have absorption in the near-ultraviolet region due to delicate thermal oxidation during high temperature melt processing such as injection molding and compression molding. However, there is a problem in that the light transmittance of the obtained optical molded product is remarkably reduced. As a result of further research, it was found that this coloring was more rigid and was greater in a polymethacrylate having an alicyclic hydrocarbon group containing more tertiary carbons. On the other hand, however, the more rigid the alicyclic hydrocarbon group in polymethacrylate is, the more excellent the heat resistance is.

Therefore, in order to obtain an optical element having low optical dispersibility and hygroscopicity and excellent heat resistance by using a polymethacrylate having a rigid alicyclic hydrocarbon group as an optical molding material, it is necessary to perform high temperature melt processing. It is essential to prevent coloring due to thermal oxidation of the.

As a means for suppressing this kind of thermal oxidation, a method in which an antioxidant is melt-mixed in a resin by an extruder or a kneader is generally used.

However, a polymer composed of a methacrylic acid ester having a rigid alicyclic hydrocarbon group in the ester portion is colored by thermal oxidation at the stage of melting and mixing an antioxidant, or until coloring is not reached. However, most of the antioxidants are deactivated, and marked thermal oxidation coloring occurs in the next molding step, which causes a problem that a colorless and transparent optical molded product cannot be obtained.

The present invention solves the above problems, while having low hygroscopicity,
An object of the present invention is to provide a resin material that is colorless and transparent, has excellent light transmittance, and is suitable for molding an optical element having excellent optical low dispersibility and heat resistance by selecting raw materials.

(Means for Solving Problems) A methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component portion of the ester and having 3 or more tertiary carbon atoms as a constituent component As 100-1
0% by weight and polymerizable monomer 0-90 copolymerizable therewith
% By weight in the general formula (I) (However, in the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are
Each independently represents an alkyl group having 1 or more carbon atoms,
Is the number of bonds to X, is an integer of 1 to 4, and X represents an n-valent aliphatic hydrocarbon group having 1 to 20 carbon atoms) and / or the general formula (II). (However, in the formula, R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹²
Are each independently an alkyl group having 1 or more carbon atoms, m is the number of bonds to Y, and is an integer of 1 to 4, and Y is an m-valent aliphatic hydrocarbon having 1 to 4 carbon atoms. And a compound represented by a group) is polymerized in the presence of the compound.

Methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component part of the ester (hereinafter,
As the methacrylic acid alicyclic ester), those containing three or more tertiary carbons in the alcohol component part thereof are used.
The compound represented by the general formula (I) and / or the compound represented by the general formula (II) has a large effect of preventing coloring, and
Such a methacrylic acid alicyclic ester is preferable from the viewpoint of improving heat resistance. Examples of such methacrylic acid alicyclic ester include norbornyl methacrylate, norbornyl methyl methacrylate, tricyclo [5.2.1.0 ^2,6 ] deca-8-yl, tricyclomethacrylate [5.2.1.0 ^{2, 6} ] deca-3-methyl,
Tricyclomethacrylate [5.2.1.0 ^2,6 ] deca-4-methyl and the like can be mentioned. From the viewpoint of heat resistance, the alicyclic hydrocarbon group of the above ester preferably has 8 or more carbon atoms.

Further, in the polymer used in the present invention, the amount of the methacrylic acid alicyclic ester used is 100 to 10% by weight with respect to the raw material monomer of the polymer, and if less than 10% by weight,
The molded article has insufficient hygroscopicity and heat resistance. From the viewpoint of heat resistance, 20% by weight or more is more preferable.

Other polymerizable monomers copolymerizable with the methacrylic acid alicyclic ester include unsaturated fatty acid esters, aromatic vinyl compounds, vinyl cyanide compounds, unsaturated dibasic acids or their derivatives, unsaturated fatty acids. Alternatively, there are derivatives thereof, and one or more of them are used.

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

As the aromatic vinyl compound, styrene, α-methylstyrene, α-ethylstyrene, α-fluorostyrene,
There are α-substituted styrenes such as α-chlorostyrene, nuclear substituted styrenes such as fluorostyrene, chlorostyrene, bromostyrene, methylstyrene, butylstyrene and methoxystyrene.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile.

The unsaturated dibasic acid and its derivative include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N-chlorophenyl. There are N-substituted maleimides such as maleimide, N-methoxyphenylmaleimide and N-carboxyphenylmaleimide, maleic acid, maleic anhydride, fumaric acid and the like.

Examples of unsaturated fatty acids and their derivatives include unsaturated fatty acids such as acrylic acid and methacrylic acid, acrylamide, methacrylamide, N-dimethylacrylamide, N-diethylacrylamide, N-dimethylmethacrylamide, and N.
-(Meth) acrylamides such as diethyl methacrylamide, calcium acrylate, calcium methacrylate, barium acrylate, barium methacrylate, lead acrylate, lead methacrylate, tin acrylate, tin methacrylate, zinc acrylate, methacrylic acid Examples thereof include metal salts of acrylic acid or methacrylic acid such as zinc.

Of these other copolymerizable monomers, the use of N-substituted maleimide is preferable for improving heat resistance.

Examples of the compound represented by the general formula (I) include 1,3,5-
Tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H,
5H) -trione, octadecyl-3- (3,5-di-
t-butyl-4-hydroxyphenyl) -propionate, tetrakis [methylene (3,5-di-t-butyl-
4-hydroxyhydrocinnamate)] methane, 1,6
-Hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate],
N, N'-hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,5-
Di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,
4,6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], etc. There is. Of these,
In particular, from the viewpoint of the effect of preventing thermal oxidation and coloring of the polymer used in the present invention, octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
-Propionate, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)]
Methane, 1,6-hexanediol-bis [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate].

In general, a phenolic compound has a radical scavenging action, and therefore it is considered unsuitable if a phenolic compound is contained in a reaction system during radical polymerization of a monomer, since side effects such as a polymerization inhibiting effect will occur. However, in radical polymerization of the monomer in the present invention, even if the compound represented by the general formula (I) is contained in the reaction system, there is almost no side effect on the polymerization. It is considered that the reason is that the phenol group portion is sufficiently protected by the tertiary alkyl groups at the o-position and the o'-position with respect to the hydroxyl group.

As the compound represented by the general formula (II), 4,4′-
Methylene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 4,4'-isopropylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-
Tridecyl) phosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-dioctyl) phosphite, 1,1,3-tris (2-methyl-)
4-ditridecylphosphite-5-t-butylphenyl) butane, 1,1,3-tris (2-methyl-4-dioctylphosphite-5-t-butylphenyl) butane, tetrakis (2,4-di) -T-butylphenyl)-
4,4'-biphenylenephosphonite, tris (2,4
-Di-t-butylphenyl) phosphite and the like. Of these, 4,4 ′ are preferred as the preferred examples from the viewpoint of the effect of preventing thermal oxidative coloration on the polymer used in the present invention.
-Butylidene-bis (3-methyl-6-t-butylphenyl-ditridecyl) -phosphite, 1,1,3-tris (2-methyl-4-ditridecylphosphite-5)
Examples include -t-butylphenyl) butane.

The compound represented by the general formula (I) and the compound represented by the general formula (II) are sufficiently effective when used alone, but when they are used in combination, an excellent synergistic effect is exhibited.

The total amount of the compound represented by the general formula (I) and the compound represented by the general formula (II) (hereinafter, referred to as “the thermal antioxidant compound of the present invention”) is the weight of the methacrylic acid alicyclic ester. It is preferably used in an amount of 0.01 to 2% by weight based on the combined product or the copolymer of the ester and other copolymerizable polymerizable monomer. If the amount of the compound for preventing thermal oxidation of the present invention is too small, the effect for preventing thermal oxidation is small, and even if it is large, the effect for preventing thermal oxidation is not improved, which is economically inadequate.

The methacrylic acid alicyclic ester or the copolymerizable polymerizable monomer with the ester is polymerized in the presence of the thermal antioxidant compound of the present invention. As a method of allowing the thermal antioxidant compound of the present invention to be present in the polymerization system, a method of dissolving the thermal antioxidant compound of the present invention in a monomer before polymerization, or a method of dissolving the compound in some monomers Examples include a method of adding a dissolved monomer solution during the polymerization, a method of dissolving the compound in a solvent and adding it during the polymerization, and allowing the compound to exist in the polymerization system. Any method may be used as long as it can be present in the polymerization system. However, from the viewpoint of workability and inclusion in a homogeneous and fine manner, a method in which the compound is dissolved and contained in the monomer before polymerization is preferable.

As the polymerization method used in the present invention, known methods such as bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like can be applied, but especially for an optical element for which it is necessary to consider mixing of impurities in the resin. For this purpose, a bulk polymerization method or a suspension polymerization method is preferable.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-di-t-butylperoxy. -3
An organic peroxide such as 3,5-trimethylcyclohexane,
Azo compounds such as azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile and azodibenzoyl, water-soluble represented by potassium persulfate and ammonium persulfate Any redox catalyst that can be used for ordinary radical polymerization, such as a catalyst and a peroxide or a combination of a persulfate and a reducing agent, can be used. The polymerization catalyst is preferably used in the range of 0.01 to 10% by weight based on the total amount of the monomers. As a polymerization regulator, a mercaptan compound, thioglycol, carbon tetrabromide, α-methylstyrene dimer and the like can be added as necessary for controlling the molecular weight.

The polymerization temperature is preferably selected from 0 to 200 ° C, and particularly preferably 50 to 120 ° C.

Solvents for solution polymerization include benzene, toluene,
Xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, dichloroethylene, etc. can be used.

The suspension polymerization is carried out in an aqueous medium, and is carried out by adding a suspending agent and, if necessary, a suspending auxiliary agent. As the suspending agent, there are water-soluble polymers such as polyvinyl alcohol, methyl cellulose and polyacrylamide, and sparingly soluble inorganic substances such as calcium phosphate and magnesium pyrophosphate. The water-soluble polymer is 0.03 to 1 with respect to the total amount of monomers. The weight% and the sparingly soluble inorganic substance are preferably used in an amount of 0.05 to 0.5% by weight based on the total amount of the monomers.

As the suspension aid, there is an anionic surfactant such as sodium dodecylbenzene sulfonate, and when a sparingly soluble inorganic substance is used as the suspension agent, it is preferable to use the suspension aid together. Suspension aid is 0.00 based on the total amount of monomers.
It is preferable to use 1 to 0.02% by weight.

The optical resin material obtained in the present invention is not particularly limited in its molecular weight, but from the viewpoint of heat resistance and mechanical properties, the weight average molecular weight (polystyrene conversion)
Is preferably in the range of 10,000 to 1,000,000, and this range is particularly preferable when it is used as a molding material.

From the viewpoint of maintaining particularly excellent low hygroscopicity, the optical resin material obtained in the present invention preferably has a carbon atom ratio of 60% by weight or more in the molecule by elemental analysis of the polymer.

The optical resin composition obtained by the present invention has a saturated water absorption of preferably 1.8% or less, more preferably 1.2% or less, and particularly preferably 0.6% or less. This can be adjusted mainly by the amount of the methacrylic acid alicyclic ester used.

The optical resin composition obtained by the present invention preferably has a glass transition point of 100 ° C. or higher, and 120 ° C.
The above is particularly preferable. Further, the Abbe number is preferably 45 or more, more preferably 50 or more, and particularly 55 or more when the optical resin composition obtained according to the present invention is used for applications such as lenses in which optical dispersion is a problem. Is preferred. These physical properties can be adjusted by appropriately selecting a monomer as a raw material of the polymer.

Further, the polymer, which is one component of the optical resin composition obtained by the present invention, unless the properties for optical use are impaired,
Random copolymer, alternating copolymer, graft copolymer,
The form of the block copolymer, polymer blend, etc. is not particularly limited.

The optical resin material obtained by the present invention has a phenolic, phosphite-based, thioether-based antioxidant (the present invention) from the viewpoints of deterioration prevention, thermal stability, moldability, processability, etc. Excluding thermal antioxidant compounds),
Release agents such as aliphatic alcohols, fatty acid esters, phthalic acid esters, triglycerides, fluorine-based surfactants, higher fatty acid metal salts, etc., other lubricants, plasticizers, antistatic agents, UV absorbers, flame retardants, heavy metal inert You may add an agent etc.

The optical resin material obtained by the present invention is an injection molding method,
The optical element can be molded by a well-known molding method such as a compression molding method, a micromold method, a floating molding method, and a Rowlinks method.

Further, the surface of the molded product obtained by the above molding method is coated with an inorganic compound such as MgF ₂ or SiO ₂ by a vacuum deposition method, a sputtering method, an ion plating method, or the like, and the surface of the molded product is a silane cup Organosilicon compounds such as ring agents, vinyl monomers, melamine resins,
By hard-coating an epoxy resin, a fluorine-based resin, a silicone resin, or the like, it is possible to improve moisture resistance, optical characteristics, chemical resistance, abrasion resistance, antifog, and the like.

Here, as the optical element, lenses for general cameras, video cameras, telescopes, laser beams, projectors, ophthalmology, sunlight collection, optical fiber lenses, pentaprism prisms, optical fibers, etc. There are optical transmission devices such as optical waveguide circuits, optical video discs, audio discs, document file discs, discs such as memory discs, and other devices that exert their functions by transmitting light.

(Examples) Next, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

Example 1 10 wt% of basic calcium phosphate as a dispersant in a separable flask of 5 equipped with a stirrer and a condenser
83 g of aqueous suspension, 0.004 g of sodium dodecylbenzene sulfonate and 1 g of sodium sulfate were added to 2400 g of pure water.
Together with stirring, and mixed with stirring to obtain a suspension medium. A composition having the following composition was added to this, and the stirring speed was set to 200 rpm, then under nitrogen atmosphere at 60 ° C. for 3 hours, then at 98 ° C. for 4 hours
Polymerized for hours.

Monomer Tricyclodecyl methacrylate 1800 g, n-butyl acrylate 200 g Polymerization initiator Lauroyl peroxide 8 g Polymerization regulator n-octyl mercaptan 2 g Thermal antioxidant compound 4,4′-butylidene-bis (3-methyl-6-t-) Butylphenyl-ditridecyl) phosphite 0.2
g, octadecyl-3- (4'-hydroxy-3 ', 5'-
Di-t-butylphenyl) propionate 0.2 g The obtained polymer particles were washed with acid, washed with water, dehydrated and then vacuum dried to obtain an optical resin composition.

Example 2 Tetrakis [methylene (3,5
—Di-t-butyl-4-hydroxyhydrocinnamate)]] An optical resin composition was produced in the same manner as in Example 1 except that 0.2 g of methane was used.

Example 3 In the same manner as in Example 1 except that 0.2 g of 1,1,3-tris (2-methyl-4-ditridecylphosphite-5-t-butylphenyl) butane was used as the thermal antioxidant compound. An optical resin composition was produced.

Example 4 Norbornyl methyl methacrylate 1000 as a monomer
g and 1000 g of methyl methacrylate were used, and tetrakis [methylene (3,5-di-
t-butyl-4-hydroxyhydrocinnamate)] methane and 0.1 g of 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-ditridecyl) phosphite. An optical resin composition was produced in the same manner as in 1.

Example 5 Tricyclodecylmethyl methacrylate 1 as a monomer
000 g and 1000 g of methyl methacrylate are used,
0.1 g of octadecyl-3- (4'-hydroxy-3 ', 5'-t-butylphenyl) propionate as a thermal antioxidant compound and 1,1,3-tris (2-methyl-4)
An optical resin composition was produced in the same manner as in Example 1 except that 0.1 g of -ditridecylphosphite-5-t-butylphenyl) -butane was used.

Example 6 600 g of tricyclodecyl methacrylate as a monomer
And 1400 g of methyl methacrylate, and octadecyl-3- (4'-hydroxy-3 ', 5'-t-butylphenyl) propionate as a thermal antioxidant compound.
05 g and 4,4'-butylidene-bis (3-methyl-6)
-T-butylphenyl-ditridecyl) phosphite.
An optical resin composition was produced in the same manner as in Example 1 except that 05 g was used.

Example 7 Tricyclodecyl methacrylate 1000 as a monomer
g and styrene 1000 g were used, and octadecyl-3- (4′-hydroxy-3 ′,
0.2 g of 5'-t-butylphenyl) propionate and 0.2 g of 1,1,3-tris (2-methyl-4-ditridecylphosphite-5-t-butylphenyl) -butane
An optical resin composition was produced in the same manner as in Example 1 except that was used.

Example 8 Tricyclodecyl methacrylate 600 as a monomer
g, 1080 g of methyl methacrylate and 320 of styrene
0.05 g of tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane as a thermal antioxidant compound and 1,1,3-tris (2-methyl-4-ditril). Decyl phosphite-5-t
-Butylphenyl) -butane, except that 0.05 g was used.
An optical resin composition was produced in the same manner as in Example 1.

Example 9 1000 g of norbornyl methacrylate as a monomer
And 1000 g of methyl methacrylate, and octadecyl-3- (4'-hydroxy-3 ', 5'-t-butylphenyl) propionate as a thermal antioxidant compound.
1 g and 4,4'-butylidene-bis (3-methyl-6)
-T-butylphenyl-ditridecyl) phosphite.
An optical resin composition was produced in the same manner as in Example 1 except that 1 g was used.

Example 10 1000 g of methyl methacrylate and 1000 g of cyclohexyl methacrylate were used as monomers, and octadecyl-3- (4'-hydroxy-3 ', 5'-t-butylphenyl) propionate as a thermal antioxidant compound was used.
2 g and 4,4'-butylidene-bis (3-methyl-6)
-T-butylphenyl-ditridecyl) phosphite.
An optical resin composition was produced in the same manner as in Example 1 except that 2 g was used.

Comparative Example 1 Tricyclodecyl methacrylate 1800 as a monomer
g and n-butyl acrylate 200 g were used, and 2,2-thiobis (4-methyl-6-) was used as a thermal antioxidant compound.
0.2 g of t-butylphenol and 4,4'-isopropylidene-diphenolalkylphosphite (however,
Alkyl is a mixture of 12 to 15 carbon atoms) 0.2
Using g, a resin composition was produced in the same manner as in Example 1.

Comparative Example 2 Tricyclodecyl methacrylate 1000 as a monomer
g and 1900 g of methyl methacrylate were used, and a resin material was produced in the same manner as in Example 1 except that the thermal antioxidant compound was not used.

Comparative Example 3 600 g of tricyclodecyl methacrylate as a monomer
And using 1400 g of methyl methacrylate,
A resin composition was produced in the same manner as in Comparative Example 2.

Comparative Example 4 Tricyclodecyl methacrylate 1800 as a monomer
g and n-butyl acrylate 200 g were used, a resin composition was produced in the same manner as in Comparative Example 2, and octadecyl-3- (4′-hydroxy-3 ′, 5 was added to the obtained dried resin particles. '-T-Butylphenyl) propionate and 4,4'-butylden-bis (3-methyl-6-
0.2 wt% of t-butylphenyl-ditridecyl) phosphite was added to each resin, and kneaded and extruded at a resin temperature of 230 ° C. using a vented single-screw extruder (screw diameter 35), and pelletized resin composition through a pelletizer. Got

Test Example The resin compositions and resin materials obtained in Examples 1 to 10 and Comparative Examples 1 to 4 were injection molded at a resin temperature of 230 ° C.
A transparent flat plate of 0 × 60 × 2 (mm) was obtained.

About this molded plate, light transmittance by wavelength, Abbe number,
The results of measuring the saturated water absorption rate and the glass transition point are shown in Table 1 below.

The light transmittance for each wavelength was measured using a spectrophotometer.

The Abbe number was measured using an Abbe refractometer.

The saturated water absorption rate (%) was determined by first drying the molded plate and measuring the dry weight, then immersing the molded plate in warm water at 70 ° C. for 72 hours, and then determining the weight (water absorption weight). It was calculated by the formula.

Further, the glass transition point was the temperature at the endothermic peak in a differential scanning calorimeter (DSC).

(Effects of the Invention) The optical resin composition obtained by the present invention has a low hygroscopic property and produces a colorless or light-colored transparent molded article, and is suitable for molding an optical element.

Claims (2)

[Claims] 1. A methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component of the ester and having 3 or more tertiary carbons as a constituent component is 100 to 10 weight parts. % And 0 to 90% by weight of a polymerizable monomer copolymerizable therewith, are represented by the general formula (I) (However, in the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are
Each independently represents an alkyl group having 1 or more carbon atoms,
Is the number of bonds to X, is an integer of 1 to 4, and X represents an n-valent aliphatic hydrocarbon group having 1 to 20 carbon atoms) and / or the general formula (II). (However, in the formula, R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹²
Are each independently an alkyl group having 1 or more carbon atoms, m is the number of bonds to Y, and is an integer of 1 to 4, and Y is an m-valent aliphatic hydrocarbon having 1 to 4 carbon atoms. Group) is used for the polymerization in the presence of a compound represented by the formula). 2. A polymer obtained from the monomer,
2. The production of an optical resin composition according to claim 1, wherein the compound represented by the general formula (I) and the compound represented by the general formula (II) are used in a total amount of 0.01 to 2% by weight. Law.