JP2515294B2 - Resin composition for optical element - Google Patents

Description

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

(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 are expanding to optical lenses for equipment, disk disks for information recording media using laser light, optical fibers, information transmitters such as connectors, and optical waveguide circuits.

Examples of the resin for such an optical element include polystyrene resin, polycarbonate resin, polymethylmethacrylate resin, polycyclohexylmethacrylate grease (JP-A-58-125742), cyclohexylmethacrylate and methylmethacrylate, styrene or other monomers. Copolymers of JP-A-58-162614 and JP-A-58-5318
JP-A-58-113214) and the like are known.

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

For example, optical lenses have 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. Polystyrene resin, polycarbonate resin, etc. have a large dispersion (optical dispersion: Abbé number of 30 to 31), so that there is a problem that chromatic aberration is large, and polymethylmethacrylate resin is not particularly hygroscopic. There is a problem in that the surface accuracy is large due to deformation due to moisture absorption.

In addition, in information recording media such as video discs, audio discs, recording / reproducing discs, recording / reproducing / erasing discs, etc. that read (write in some cases) information using laser light, low birefringence, low hygroscopicity, and heat resistance. However, polystyrene resin, polycarbonate resin, etc. have a problem that many errors occur during reproduction because of large birefringence, and polymethylmethacrylate resin has a problem in that the surface accuracy of the disk machine is affected by moisture deformation. There was a problem that a crease occurred and an error occurred during playback.

However, among the above resins, polymethylmethacrylate resin, except for the drawback of being easily deformed by moisture absorption,
It has excellent optical properties and can be said to be the best resin in this respect.

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

(Problems to be solved by the invention) As a resin having low optical dispersibility and low hygroscopicity, a (co) methacrylate having an alicyclic hydrocarbon group having a rigid structure due to an alcohol component of an ester is used. Since a polymer is preferable, the application as an optical element molding material was examined using such a (co) polymer.

However, (co) polymers containing these alicyclic hydrocarbon group-containing methacrylates as constituent components to a certain extent or more are exposed to the near-ultraviolet region due to delicate thermal oxidation during high temperature melt processing such as injection molding and compression molding. There is a problem that coloring occurs due to the formation of a trace substance having absorption, and 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 larger in a rigid resin and in a polymethacrylate having an alicyclic hydrocarbon group containing many 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 with excellent heat resistance and low optical dispersibility and hygroscopicity, polymethacrylate having rigid alicyclic hydrocarbon group is used as an optical molding material. It is essential to prevent coloration due to thermal oxidation.

INDUSTRIAL APPLICABILITY The present invention solves the above-mentioned problems, is excellent in light transmittance while having low hygroscopicity, and is a resin composition suitable for molding an optical element having optically low dispersibility and good heat resistance by selecting raw materials. The purpose is to provide things.

(Means for Solving the Problems) The present invention relates to methacrylic acid having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component portion of an ester and containing 3 or more tertiary carbon atoms. Ester as a constituent
Polymer having 10% by weight or more and general formula (I) (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 or more carbon atoms, and n is the number of bonds to the group R 2. To an integer of 4 and R is an aliphatic hydrocarbon group having 1 to 4 carbon atoms and represented by an n-valent aliphatic hydrocarbon group) for the synthesis of the above polymer. The present invention relates to a resin composition for an optical element, which is obtained by mixing the organic phosphorus compound without being present at the time of polymerization.

As a methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component of the ester,
The alcohol component containing three or more tertiary carbons is used, and the organophosphorus compound of the present invention has a large color-preventing effect on such a methacrylic acid ester. The acid ester is preferable from the viewpoint of improving heat resistance. Examples of such methacrylic acid esters include norbornyl methacrylate, norbornyl methyl methacrylate, and tricyclo [5,2,1,0 ^2,6 ] deca-8-methacrylate.
Ile, tricyclomethacrylate [5,2,1,0 ^2,6 ] deca-3
-Methyl, tricyclo [5,2,1,0 ^2,6 ] deca-4-methyl and the like can be mentioned. Also, 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 these methacrylic acid esters used is 10% by weight or more,
It is preferably about 20% by weight. If it is less than 10% by weight, the low hygroscopicity of the molded article is not sufficient, and in this respect, 20% by weight or more is preferable.

Other polymerizable monomers copolymerizable with the above-mentioned methacrylic acid ester include unsaturated fatty acid ester, aromatic vinyl compound, vinyl cyanide compound, unsaturated dibasic acid or its derivative, unsaturated fatty acid or its derivative. Etc., and one or more of these are used.

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

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

Vinyl cyanide compounds include acrylonitrile,
There are methacrylonitrile and the like.

Unsaturated dibasic acids and their derivatives include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide and N-methylmaleimide. N-, such as -chlorophenylmaleimide, N-methoxyphenylmaleimide and N-carboxyphenylmaleimide
Substituted maleimide, maleic acid, maleic anhydride, fumaric acid, etc. are available.

Unsaturated fatty acids and their derivatives include acrylic acid,
Unsaturated fatty acids such as methacrylic acid, acrylamide, methacrylamide, N-diethylacrylamide, N-diethylacrylamide, N-dimethylmethacrylamide, N-diethylmethacrylamide, and other (meth) acrylamides,
Calcium acrylate, calcium methacrylate, barium acrylate, barium methacrylate, lead acrylate, lead methacrylate, tin acrylate, tin methacrylate,
Examples thereof include metal salts of acrylic acid or methacrylic acid such as zinc acrylate and zinc methacrylate.

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

The polymer used in the present invention is a homopolymer of a methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component portion of the ester and containing 3 or more tertiary carbons. , A copolymer of these ethacrylic acid esters or a copolymer of a methacrylic acid ester and another monomer copolymerizable with the methacrylic acid ester.

The saturated water absorption of the above polymer is preferably 1.8% or less, 1.
2% or less is more preferable, and 0.6% or less is particularly preferable. This can be adjusted mainly by the amount of the methacrylic acid alicyclic ester used.

The polymer preferably has a glass transition point of 100 ° C. or higher, more preferably 120 ° C. or higher. Further, the Abbe number is preferably 45 or more, more preferably 50 or more, when the resin composition for an optical element according to the present invention is used in applications where optical dispersion of a lens or the like becomes a problem.
Particularly, 55 or more is preferable. These physical properties can be adjusted by appropriately selecting a monomer as a raw material of the polymer.

The polymer, which is one component of the optical resin material according to the present invention, contains the organophosphorus compound represented by the general formula (I) in order to inhibit the properties for optical use and prevent thermal oxidation and coloring of the polymer. It In general, other organophosphorus compounds known to be effective in preventing thermal oxidation and coloring of polymers have no or little effect in the present invention.

Among the organic phosphorus compounds represented by the general formula (I), the general formula (II) (Wherein, R ⁵ ′ and R ⁶ ′ are each independently an alkyl group having 8 to 17 carbon atoms, and n and R are the same as those in the general formula (I)) Is preferred.

Examples of the organic phosphorus compound include 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-ditril) Decylphosphite-5
t-butylphenyl) butane and the like. Of these,
Particularly preferred from the viewpoint of the effect of preventing thermal oxidative coloration on the polymer used in the present invention, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 1,1 , 3-Tris (2-methyl-4-
Ditridecyl phosphite-5-t-butylphenyl)
Butane is an example. These specific organophosphorus compounds based on these o-methyl-p-dialkylphosphite-m-t-butylphenyl structures are used for thermal oxidation of methacrylic acid ester polymers having an alicyclic hydrocarbon group used in the present invention. Although it has an excellent effect of suppressing coloring, its mechanism of action is not clear.

The amount of the organic phosphorus compound used is 0.01 with respect to the polymer.
~ 2 wt% is preferred. If it is less than 0.01% by weight, the effect of addition tends to decrease, and if it exceeds 2% by weight, the effect does not increase and it is not economically advantageous.

As a method for producing the polymer used in the present invention, known methods such as radical polymerization, ionic polymerization, coordination polymerization and transfer polymerization can be applied. For example, in the presence of a polymerization initiator, it can be produced by a method such as bulk polymerization, solution polymerization, suspension polymerization, etc., but especially for an optical element for which it is necessary to consider contamination of impurities in the resin, bulk polymerization or The suspension polymerization method is preferred.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-di-t-butylperoxy- Organic peroxides such as 3,3,5-trimethylcyclohexane, azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, etc. Azo compounds, water-soluble catalysts typified by potassium persulfate and ammonium persulfate, and redox catalysts obtained by combining peroxides or persulfates with reducing agents can be used as long as they can be used in ordinary radical polymerization. The polymerization catalyst is preferably used in the range of 0.01 to 10% by weight based on the total amount of 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.

As a solvent in the solution polymerization, benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, dichloroethylene or the like can be used.

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. Suspending agents include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, etc., and sparingly soluble inorganic substances such as calcium phosphate, magnesium pyrophosphate, etc. The water-soluble polymer is 0.03 to 1 relative 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.
It is preferable to use 001 to 0.02% by weight.

The polymer used 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 (converted to standard polystyrene by gel permeation chromatography) is 10,000 to 1
Those in the range of 000000 are preferable, and those in this range are particularly preferable when used as a molding material.

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

The polymer used in the present invention is not particularly limited in the form such as a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer, a polymer blend, etc., as long as the transparency is not impaired.

The organophosphorus compound can be mixed with the polymer of the present invention by a method such as melt-kneading with the polymer or a method of dissolving both in a solvent and distilling the solvent off.

Since the polymer of the present invention tends to be colored yellow when heated, the above method of melt-kneading cannot be said to be preferable, but when it is necessary to supply the resin material of the present invention in pellet form, It is necessary to melt-knead using an extruder or the like, and in this case, the coloring of the resin material can be suppressed low. That is, even in such a case, the organophosphorus compound is useful.

The resin composition for an optical element according to the present invention, when used, has the above-mentioned organic compounds such as phenol-based, phosphite-based, thioether-based, etc., from the viewpoints of deterioration prevention, thermal stability, moldability, processability and the like. Antioxidants other than phosphorus compounds, fatty alcohols, fatty acid esters, phthalates, triglycerides, fluorine-based surfactants, release agents such as higher fatty acid metal salts, other lubricants, plasticizers, antistatic agents, ultraviolet rays Absorbents, flame retardants, heavy metal deactivators, etc. may be included.

The resin material for molding an optical element according to the present invention can be molded by a known molding method such as an injection molding method, a compression molding method, a micro molding method, a floating molding method, and a Rowlinks method.

Also, the surface of the molded product obtained by the above-mentioned molding method is coated with an inorganic compound such as MgF ₂ or SiO ₂ by the vacuum deposition method, the sputtering method or the ion plating method. By hard coating organic silicon compounds such as silane coupling agents, vinyl monomers, melamine resins, epoxy resins, fluorine resins, silicone resins, etc., moisture resistance, optical characteristics, chemical resistance, abrasion resistance ， It can improve anti-fog and so on.

The resin composition according to the present invention can be molded into various optical elements by the molding method as described above.

Here, as optical elements, lenses for general cameras, video cameras, telescopes, laser beams, projectors, ophthalmology, sunlight collection, optical fiber lenses, prisms such as pentaprisms, and optical fibers are used. There are elements that perform their functions by transmitting light, such as optical transmission elements such as optical waveguide circuits, optical video disks, audio disks, document file disks, and disks such as memory disks.

(Function) The organophosphorus compound represented by the general formula (I) is a methacrylic acid ester polymer or copolymer having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component of the ester. On the other hand, it exerts an effect of suppressing thermal oxidation and prevents coloring of the polymer due to thermal oxidation.

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

Comparative Example 1 10% by weight of basic calcium phosphate as a dispersant was added to a separable flask 5 equipped with a stirrer and a condenser.
Aqueous suspension 83g, sodium dodecylbenzene sulfonate
Add 0.004 g and 1 g of sodium sulfate together with 2400 g of pure water,
The mixture was stirred and mixed to obtain a suspension medium. The following composition was added thereto, the stirring speed was 200 rpm, and polymerization was carried out in a nitrogen atmosphere at 60 ° C. for 3 hours and subsequently at 98 ° C. for 4 hours.

The obtained polymer particles were pickled, washed with water, dehydrated and dried, and then extruded at a resin temperature of 230 ° C. using a vented single-screw extruder (screen diameter 35 mmφ) and passed through a pelletizer to obtain a pellet-shaped resin material.

Example 1 1000 g of the polymer particles obtained in Comparative Example 1 (pickled, washed with water, dehydrated and dried) and 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-) as an organic phosphorus compound. 2 g of di-tridecyl) phosphite was extruded in the same manner as in Comparative Example 1 to obtain a pellet-shaped resin material.

Example 2 Instead of the organophosphorus compound of Example 1, 1 g of 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-ditridecyl) phosphite and octadecyl-3-
Example 1 except that 1 g of (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate was used.
A pellet-shaped resin material was obtained in the same manner as in.

Comparative Example 2 Instead of the organophosphorus compound of Example 1, octadecyl-
A pellet-like resin material was obtained in the same manner as in Example 1 except that 2 g of 3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate was used.

Comparative Example 3 A pellet-shaped resin material was prepared in the same manner as in Example 1 except that 2 g of 2,2-thiobis (4-methyl-6-t-butylphenol) was used instead of the organophosphorus compound of Example 1. Got

Comparative Example 4 Polymer particles were obtained in the same manner as in Comparative Example 1, except that 600 g of tricyclodecyl methacrylate and 1400 g of methyl methacrylate were used as the monomers, and further a pellet-shaped resin material was obtained.

Example 3 1000 g of polymer particles obtained in Comparative Example 4 (pickled, washed with water, dehydrated, and dried) and 1,1,3-tris (2-methyl-4′-ditridecylphosphite) as an organic phosphorus compound −
2 g of 5-t-butylphenyl) butane was extruded in the same manner as in Comparative Example 1 to obtain a pellet-shaped resin material.

Example 4 Instead of the organophosphorus compound of Example 3, 1,1,3-tris (2-methyl-4'-ditridecylphosphite-5-
1 g of t-butylphenyl) butane and 2,2-thiobis (4
-Methyl-6-t-butylphenol) was used in the same manner as in Example 3 except that 1 g of a resin material was obtained.

Comparative Example 5 A pellet-shaped resin material was obtained in the same manner as in Example 3 except that 2 g of 4,4'-isopropylidene-diphenol tridecyl phosphite was used in place of the organophosphorus compound of Example 3.

Test Example 1 The resin materials obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were injection-molded at a resin temperature of 230 ° C. to obtain 50 × 60 × 2 (mm) transparent flat plates.

Table 1 below shows the results of measuring the light transmittance, Abbé number, saturated water absorption and glass transition point of each of the molded plates by wavelength.

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

In addition, the Atsube number was measured using an Abebe 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 its weight (water absorption weight). It asked for by the formula of.

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

Comparative Example 6 As a monomer, tricyclodecyl methacrylate 1800
g and n-butyl acrylate 200 g were replaced with methyl methacrylate 2000 g, polymer particles were obtained in the same manner as in Comparative Example 1, and pelletized resin material was obtained.

Comparative Example 7 1000 g of the polymer particles obtained in Comparative Example 6 (pickled, washed with water, dehydrated and dried) and 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-ditridecyl) phosphite 2 g was extruded in the same manner as in Comparative Example 1 to obtain a pellet-shaped resin material.

Comparative Example 8 As a monomer, tricyclodecyl methacrylate 1800
Polymer particles were obtained according to Comparative Example 1 except that 1000 g of methyl methacrylate and 1000 g of cyclohexyl methacrylate were used instead of g and 200 g of n-butyl acrylate to obtain a resin material in pellet form.

Comparative Example 9 1000 g of the polymer particles (pickled, washed with water, dehydrated and dried) obtained in Comparative Example 8 and 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-ditridecyl) phosphite 2 g was extruded in the same manner as in Comparative Example 1 to obtain a pellet-shaped resin material.

Comparative Example 10 1000 g of the polymer particles obtained in Comparative Example 1 (pickled, washed with water, dehydrated and dried) and 2 g of tris (2,4-di-t-butylphenyl) phosphite were used in the same manner as in Comparative Example 1. Was extruded to obtain a pellet-shaped resin material.

Comparative Example 11 The polymer particles obtained in Comparative Example 4 (those pickled, washed with water, dehydrated and dried) 1000 g and tris (2,4-di-t-butylphenyl) phosphite 2 g were used in the same manner as in Comparative Example 1. Was extruded to obtain a pellet-shaped resin material.

Test Example 2 The resin materials obtained in Comparative Examples 6 to 11 were used and tested in accordance with the test examples. The results are shown in Table 2.

(Effects of the Invention) The resin composition according to the present invention is less likely to be colored by thermal oxidation and has optical low dispersion, low hygroscopicity, and heat resistance.
Moreover, a molded product excellent in light transmittance is also produced, which is suitable for molding an optical element.

Claims (5)

(57) [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 carbon atoms as a constituent component.
Polymer having 10% by weight or more and general formula (I) (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 or more carbon atoms, and n is the number of bonds to the group R 2. To an integer of 4 and R is an aliphatic hydrocarbon group having 1 to 4 carbon atoms and represented by an n-valent aliphatic hydrocarbon group) for the synthesis of the above polymer. A resin composition for an optical element, which is obtained by mixing the above-mentioned organic phosphorus compound without being present at the time of polymerization. 2. An organic phosphorus compound represented by the general formula (I) is a compound represented by the general formula (II) (However, R ⁵ ′ and R ⁶ ′ each independently have 8 to 17 carbon atoms.
The resin composition for an optical element according to claim 1, which is an organic phosphorus compound represented by the formula: 3. A compound represented by the general formula (I) is 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-ditridecyl) phosphite or 1,1,3-tris (2-methyl-4)
-The resin composition for optical elements according to claim 1, which is ditridecylphosphite-5-t-butylphenyl) butane. 4. A methacrylic acid ester having a polymer having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component of the ester and having at least three tertiary carbons.
~ 20% by weight and other polymerizable monomers copolymerizable therewith 0
The resin composition for an optical element according to claim 1, which is a polymer obtained by polymerizing 80 to 80% by weight. 5. A methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the alcohol component portion of the ester and containing 3 or more tertiary carbons is norbornyl methacrylate or normethacrylic acid nor. Bornylmethyl, tricyclo [5.2.1.0 ^2,6 ] deca-8-yl, tricyclo [5.2.1.0 ^2,6 ] deca-3-methyl methacrylate,
The resin composition for an optical element according to claim 1, which is tricyclo [5.2.1.0 ^2,6 ] deca-4-methyl methacrylate.