JPS62199605A - Optical resin material - Google Patents

Abstract

PURPOSE:To provide a resin material of high refractive index with low hygroscopicity and high heat resistance, switable for optical devices and information-recording bases, comprising a resin prepared by copolymerization between a methacrylic ester and unsaturated carboxylic acid metal salt. CONSTITUTION:The objective resin material comprising a resin prepared by copolymerization between (A) a methacrylic ester having 5-22C alicyclic hydrocarbon group in its ester section (e.g. dimethyl adamantyl methacrylate, camphene methacrylate) and (B) an unsaturated carboxylic acid metal salt (e.g. Ca, Mg or Ni salt of unsaturated carboxylic acid such as acrylic acid, itaconic acid or sorbic acid) and furthermore, if needed, (C) 0-30wt% based on the whole amount of the monomers, of a vinyl monomer such as styrene or acrylonitrile in a weight ratio A/B of pref. 20/80-90/10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical resin material that has a high refractive index, low hygroscopicity, and excellent heat resistance.

(Prior Art) Plastic optical elements are lighter than glass optical elements, do not require polishing, and can be mass-produced. Therefore, in recent years, demand has been expanding for optical lenses for cameras, copying machines, laser optical equipment, etc., information recording disks using laser light, and information transmission bodies such as optical fibers.

However, there are some difficulties in using conventional transparent plastic materials. For example, heat resistance.

Low hygroscopicity 9 There is a problem in that it has defects in mechanical properties, optical properties such as refractive index and dispersion, optical birefringence, etc.

For example, optical lenses require optical physical properties such as high refractive index and low dispersion, as well as low moisture absorption and heat resistance to minimize surface accuracy fluctuations due to moisture absorption and deformation.

Precision moldability is particularly required. On the other hand, polystyrene resin, polycarbonate resin, and the like have a problem in that they have large dispersion and a large occurrence of dichromatic aberration. Furthermore, since polymethyl methacrylate (PMMA) resin has a high moisture absorption rate, there is a problem in that the surface precision deteriorates significantly due to moisture absorption and deformation.

Also, information reading using laser light.

High-density information recording media used for writing and the like are particularly required to have low birefringence, low moisture absorption, heat resistance, impact resistance, and the like. On the other hand, optical disks molded from P8 resin, polycarbonate resin, or the like have a large birefringence and therefore have a problem of large errors during reading. Furthermore, in the case of PMMA resin, there is a problem in that it undergoes large deformation due to moisture absorption, similar to the case of optical lenses.

However, among these resins, optical elements using PMMA resin can be said to be the most excellent except for the problem of deformation due to moisture absorption.

Therefore, various plastic optical elements made of new transparent resins that have optical properties comparable to those of PMMA but have improved hygroscopicity have recently been studied.

For example, polycyclohexyl methacrylate<PCHM
A) Poly(isobornyl methacrylate) has been proposed as an optical resin material (Japanese Patent Application Laid-Open No. 58-125742
(see Japanese Patent Application Laid-open No. 162651/1983).

On the other hand, copolymers of c)lohexyl methacrylate, methyl methacrylate, styrene, etc. have also been proposed (
! ! f! j Publication No. 58-5318, Japanese Patent Publication No. 58-1
13, JP-A-58-154751, and JP-A-58-162614).

Further, as a polymer having a high refractive index, a polymer obtained by addition polymerization of a vinyl monomer compound containing a metal salt of (meth)acrylic acid (Japanese Patent Application Laid-open No. 58-16460
No. 8), a resin with a metal-oxygen bond introduced (Unexamined Japanese Patent Publication No. 5
No. 7-5705, a polymer in which the acid moiety of a specific styrene having a substituent such as a carboxylic acid is a metal salt (JP-A-58
Resins into which metals are introduced, such as No. 171407, have also been proposed.

(The problem that the invention seeks to solve) However, as mentioned above, resins with metals introduced.

Although it exhibits a certain degree of high refractive index, it has the disadvantage of poor hygroscopicity.

The present invention solves these problems and provides an optical resin material that has low hygroscopicity, high refractive index, and excellent heat resistance.

(Means for solving the problems) The present invention provides (A) a methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the ester moiety;
B) An optical resin material containing a resin obtained by copolymerizing a metal salt of an unsaturated carboxylic acid.

The above-mentioned methacrylic acid ester having an alicyclic hydrocarbon group not only imparts properties (transparency, low dispersion, etc.) that can be used as an optical resin material.

Essential for providing low moisture absorption and heat resistance.

As a methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the ester moiety.

Dimethyl adamantyl methacrylate, adamantyl methacrylate, adamantyl methacrylate, cyclopentyl methacrylate, cyclododenyl methacrylate, norbornane methyl methacrylate, isobornyl methacrylate, norbornane methacrylate, bornyl methacrylate.

Tricyclodecyl methacrylate, fenthyl methacrylate, infenthyl methacrylate.

Menthyl methacrylate, trimethylcyclohexyl methacrylate, trimethylbicyclohebutyl methacrylate, camphene methacrylate, etc.

Examples of the metal salt of unsaturated carboxylic acid include metal salts of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, sorbic acid, and maleic acid.

The metals are calcium, magnesium, and zinc.

Aluminum, barium, soot, lead, cobalt.

Manganese, nickel, LIJ thium, strontium,
There are copper, bismuth, etc.

The methacrylic ester having an alicyclic hydrocarbon group and the metal salt of an unsaturated carboxylic acid are used in a weight ratio of 20/80 to 90/10. If this weight ratio is less than 20/80, low moisture absorption and heat resistance will be poor, and if it exceeds 90/10, high refractive index resin will be difficult to burn.

In addition to the above-mentioned methacrylic esters having alicyclic hydrocarbon groups and metal salts of unsaturated carboxylic acids.

Other vinyl monomers that can be copolymerized with these can also be copolymerized. Other vinyl monomers.

Preferably, it is used in an amount of 0 to 30% by weight, based on the total amount of monomers. Too much content tends to adversely affect heat resistance and high refractive properties.

Other vinyl monomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic. Methacrylic acid or acrylic acid esters such as 2-ethylhexyl acid and cyclohexyl acrylate, styrene, vinyltoluene, α-
Aromatic vinyl compounds such as methylstyrene, α-fluorostyrene, α-chlorostyrene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide , N-substituted maleimide such as N-phenylmaleimide, N-methylphenylmaleimide, N-chlorophenylmaleimide, maleic acid.

Examples include dibasic acids such as phenyl acid or their acid anhydrides, methacrylic acid, and acrylic acid.

For copolymerization of these monomers, known methods such as radical polymerization, ionic polymerization, coordination polymerization, etc. can be applied.

For example, bulk polymerization and solution polymerization in the presence of a polymerization initiator.

Although it can be manufactured using methods such as suspension polymerization, bulk polymerization or suspension polymerization methods are recommended for optical element applications that require considerations such as productivity and workability, or contamination of impurities in the resin. is preferred.

Examples of initiators used in the polymerization include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanony), 1,1-di-t- Organic peroxides such as butylperoxy-linked trimethylcyclohexane, azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, etc. Any of those that can be used in normal radical polymerization can be used, such as an azo compound, a water-soluble catalyst such as potassium persulfate, and ammonium persulfate, and a redox catalyst using a combination of a peroxide or a persulfate and a reducing agent. The polymerization catalyst is used in an amount of 0.01 to 10% by weight based on the total amount of monomers.
It is preferable to use within the range of . Mercagtan compounds, thioglycol, carbon tetrabromide as polymerization regulators.

α-methylstyrene dimer or the like may be added as necessary to adjust the molecular weight.

The polymerization temperature is preferably selected appropriately between 0 and 200°C, particularly preferably 50 and 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.

Suspension polymerization is carried out in an aqueous medium, with addition of S clouding agents and, if necessary, suspension aids. Examples of suspending agents include water-soluble polymers such as polyvinyl alcohol, methylcellulose, and polyacrylamide, and sparingly soluble inorganic substances such as calcium phosphate and magnesium pyrophosphate. ~1% by weight and poorly soluble inorganic substances are 0.05 to 0.5 weight f based on the total amount of monomers.
! It is preferable to use %.

IufllJ agents include anionic surfactants such as sodium dodecylbenzenesulfonate, and when a poorly soluble inorganic substance is used as a suspending agent, it is preferable to use them together. The suspension aid is 0.0% based on the total amount of monomers. OO1~0
．． It is preferable to use 0.02% by weight.

The molecular weight of the polymer used in the present invention is not particularly limited, but from the viewpoint of heat resistance, mechanical properties, weight average molecular weight (measured by gel permeation chromatography, standard polystyrene equivalent) of 10.000 to 1.
A value in the range of 000.000 is preferred, and a value in this range is particularly preferred when used as a molding material.

The amount of volatile components, mainly consisting of residual unreacted sulfur, in the copolymer is preferably 1.5 or less.

In addition, in the copolymer used in the present invention, from the viewpoint of maintaining particularly excellent low hygroscopicity, the ratio of carbon atoms in the molecule according to elemental analysis of the bipolymer is preferably 60% by weight or more. .

The optical resin material according to the present invention includes a carboxylic acid having a benzene nucleus in order to improve transparency.

For example, benzoic acid, β-phenylpropionic acid.

It is preferable to contain β-phenyl phtanoic acid or the like. If it is too small, the effect of improving transparency will be small, and if it is too large, it will adversely affect the heat resistance of the optical resin material. A carboxylic acid with a benzene nucleus.

It may be present during the polymerization of the monomers described above, and after the bipolymerization,
It may be incorporated by adding and kneading.

When using the optical resin material according to the present invention,
From the viewpoint of prevention of deterioration, thermal stability, moldability, processability, etc.
Phenol type, phosphite type.

Antioxidants such as thioethers, aliphatic alcohols, fatty acid esters, phthalate esters, triglycerides, fluorine surfactants, mold release agents such as higher fatty acid metal salts, other lubricants, plasticizers, antistatic agents, ultraviolet absorption A flame retardant, a double metal deactivator, and the like may be added.

The optical resin material of the present invention can be used in various optical devices.

For example, plastic lenses, prisms, etc.

It can be suitably used as an information recording substrate for audio discs, video discs, information discs, etc.

It can be molded by injection molding or cast polymerization.

(Example) The present invention will be explained below based on two specific examples.

In the examples, "part" means "part by weight" and "9%" means % by weight.

In addition, the saturated water absorption rate in the examples is 6 relative to the weight of the resin plate.
The rate of weight increase after the sample was immersed in 0°C hot water for one week is expressed.

Example 1 Tricyclodecyl methacrylate 509 lead methacrylate in a 500cc Erlenmeyer flask with three-way activity
1009 Methyl methacrylate
259β-phenylpropionic acid 25
9 lauroyl peroxide o, sg2.5
-dimethyl-2,5-t-p 0.29 tylperoxyhexane n-octyl mercaptan 0.2g mixed.
After dissolving and charging the flask, the inside of the flask was purged with nitrogen for about 1 hour, and then immersed in 65° C. hot water, and prepolymerized for about 30 minutes under a nitrogen stream.

Subsequently, this prepolymerized product was subjected to cell cast polymerization to produce a cast plate.

Cell cast polymerization was carried out in the following manner. size 25
The outer periphery of two glass plates measuring 0 [+1111 x 260 mm and 4 trm in thickness was covered with a flexible vinyl chloride gasket, and the two glass plates were assembled and prepared so that the distance between them was 3 cabinets. .

Which prepolymer was injected into this cell first, and heated to 60℃ for 8 hours.
Polymerization was performed at 90° C. for 2 hours and at 120° C. for 5 hours to obtain a transparent cast plate.

The total light transmittance, saturated moisture absorption, heat distortion temperature, and refractive index of this plastic plate were measured and are shown in Table 1.

Example 2 The same procedure as in Example 1 was carried out except that the monomer components in Example 1 were changed to 50 g of tricyclodecyl methacrylate, 100 g of zinc acrylate, and 509 of β-phenylbutanoic acid.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the monomer components in Example 1 were changed to tricyclodecyl methacrylate (50 g), methyl methacrylate (1259), and β-phenylpropionic acid (259). The refractive index was low.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the monomer components in Example 1 were changed to lead methacrylate 1009 methyl methacrylate 759 β-phenylpropionic acid 259. The saturated moisture absorption rate was high.

Table 1 shows the properties of the copolymers obtained in Examples 1 and 2 and Comparative Examples 1 and 2.

Table 1 Characteristics (Effects of the Invention) The optical resin material according to the present invention has low hygroscopicity, high refractive index, and high heat distortion temperature.

Claims (1)

[Claims] 1. A resin obtained by copolymerizing (A) a methacrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the ester moiety and (B) an unsaturated carboxylic acid metal salt. An optical resin material containing.