JPH04249505A - Optical resin - Google Patents

Abstract

PURPOSE:To prepare an optical resin excellent in optical properties, such as refractive index, chromatic abberation, or transparency, and mechanical properties and emitting little odor by polymerizing a monomer component contg. a specific organosulfur compd. CONSTITUTION:An optical resin which is obtd. by polymerizing a monomer component contg. an organosulfur compd. of the formula (wherein R is CH2=CH or CH2=CH=CH2; and X is H or methyl). The compd. can be easily prepd., e.g. by reacting 1mol of 4,4'-thiobenzenethiol with 2mol of vinyl acrylate in the presence of a basic catalyst such as triethylamine pref. at 0-100 deg.C for 30min to 48hr, and accounts for 1-100wt.% of the monomer component. Styrene, p- methylstyrene, p-chlorostyrene, o-chlorostyrene, vinyl acetate, etc., can be used as comonomers.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical resins, and more particularly to optical resins that are excellent in optical properties such as refractive index, chromatic aberration, and transparency, as well as various mechanical properties.

0002

BACKGROUND OF THE INVENTION In recent years, synthetic resin materials that are lightweight, easy to mold, have excellent impact resistance, and are dyeable have been used as lens materials in place of inorganic glass. As the synthetic resin material, for example, polymethyl methacrylate, polydiethylene glycol bisallyl carbonate, polystyrene, and polycarbonate are known. Although the polymethyl methacrylate and polydiethylene glycol bisallyl carbonate have excellent lightness and impact resistance, their refractive index is as low as about 1.49, so when used as a lens, a thicker lens is required compared to inorganic glass. The drawback is that it is not suitable for high magnification and weight reduction. Also,
Although polystyrene and polycarbonate have a high refractive index of about 1.58 to 1.59, since they are thermoplastic resins, they have the problem of easily causing optical distortion due to birefringence during injection molding. It has drawbacks such as poor durability and scratch resistance.

[0003]Recently, several technical proposals have been made to improve these conventional drawbacks by providing a high refractive index. For example, JP-A-1-309002 discloses a plastic lens made by curing a distyryl-type organic sulfur compound and a trivalent or tetravalent thiol compound; Furthermore, a sulfur-containing plastic lens is produced by mixing and curing a compound having 1.3 or more vinyl groups on a molar average and a compound having 1.1 or more thiol groups on a molar average in a specific ratio. JP-A No. 2-58001 discloses that a dimercaptobenzene nucleus substituted product and at least 2
High refractive index optical resins obtained by reacting with compounds having reactive unsaturated groups have been proposed.

0004

[Problems to be Solved by the Invention] However, although the above-mentioned optical resins have a high refractive index, they have problems in terms of chromatic aberration, and furthermore, the thiol compounds used as raw materials have a strong odor, making them difficult to work in. There is also a problem in that handling properties are poor due to the high viscosity of the raw resin.

Therefore, an object of the present invention is to create a resin that has desirable refractive index, chromatic aberration, transparency, etc. as a resin for plastic lenses or other optical applications, has excellent various mechanical properties, has a low specific gravity, and has low odor. An object of the present invention is to provide an optical resin that has excellent handling properties when cured.

[0006]

[Means for Solving the Problems] According to the present invention, the following general formula 2 (wherein R is CH2=CH or CH2CH=C
H2 and X represents a hydrogen atom or a methyl group) (hereinafter referred to as organic sulfur compound A)
Optical resin obtained by polymerizing raw material monomers containing

[0007]

[Case 2]

The present invention will be explained in more detail below.

The optical resin of the present invention is characterized in that it contains the organic sulfur compound A as an essential raw material monomer.

The organic sulfur compounds A mentioned above as essential raw material monomers in the present invention are specifically listed as compounds represented by the following chemical formulas 3, 4, 5, and 6,
When used, they can be used alone or as a mixture.

[0011]

[Chemical formula 3]

0012

[C4]

[0013]

[C5]

[0014]

[C6]

To prepare the organic sulfur compound A, for example, 1 mole of 4,4'-thiobenzenethiol and 2 moles of vinyl acrylate are preferably reacted in the presence of a basic catalyst such as triethylamine. It can be easily obtained by reacting at a temperature of 0 to 100°C for 30 minutes to 48 hours.

The blending ratio of the organic sulfur compound A to the entire raw material monomer is not particularly limited, but is preferably 1 to 10% of the total raw material monomer.
0% by weight, particularly preferably in the range from 30 to 100% by weight. In addition, when the organic sulfur compound A is used in an amount of 1 to 30% by weight, it can also be used as a high-performance crosslinking agent having a high refractive index.

In the present invention, monomers other than the organic sulfur compound A that can be used as raw material components include, for example, styrene, p-methylstyrene, p-
Chlorstyrene, o-chlorostyrene, p-bromstyrene, o-bromstyrene, vinyl acetate, vinyl propionate, methyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, bromine Phenyl methacrylate, acrylonitrile, methacrylonitrile, dibenzyl maleate, dibenzyl fumarate, dibenzyl itaconate, dibenzyl mesaconate, 2,2-
Bis(4-methacryloyloxyethoxyphenyl)propane, 2,2-bis(4-acryloyloxyethoxyphenyl)propane, diethylene glycol bisallyl carbonate, diallyl tetrachlorophthalate, diallylphthalate, p-divinylbenzene, m -Divinylbenzene, divinylbiphenyl, ethylene glycol bismethacrylate, diethylene glycol bismethacrylate, ethylene glycol bisacrylate, diethylene bisacrylate, dipropylene glycol bismethacrylate, triethylene glycol bisacrylate
Tetraethylene glycol bisacrylate, bisphenol A bismethacrylate, diallyl tetrachlorophthalate, diallyl isophthalate, allyl methacrylate, propylene glycol bisacrylate, hexaethylene glycol bisacrylate Preferred examples include octaethylene glycol bisacrylate, decaneethylene glycol bisacrylate, and the like.

The high refractive index optical resin of the present invention can be prepared, for example, by subjecting the raw material monomers mentioned above to thermal polymerization or copolymerization in the presence of a radical polymerization initiator. As the radical polymerization initiator, organic peroxides or azo compounds having a 10-hour half-life temperature of 160° C. or lower can be used, and specific examples include benzoyl peroxide, diisopropyl peroxydicarbonate, and tertiary butyl. Peroxy-2-ethylhexanoate, tert-butyl peroxypivalate, tert-butyl peroxydiisobutyrate, lauroyl peroxide, tert-butyl peroxy acetate, tert-peroxyoctoate, t-butyl peroxybenzoate, azo Bisisobutyronitrile and the like can be used alone or as a mixture. The amount of the radical polymerization initiator used is 10 parts by weight or less, particularly preferably 5 parts by weight or less, based on 100 parts by weight of the total monomers charged.

In order to carry out the thermal polymerization or copolymerization, for example, each of the monomers and a radical polymerization initiator are directly charged into a desired mold, preferably at 0 to 200°C and 1 to 48°C.
Polymerization can be achieved by heating for a period of time. At this time, the polymerization system is preferably carried out under an inert gas atmosphere such as nitrogen, carbon dioxide, or helium. Also, before the polymerization, the raw material monomers are heated at, for example, 0 to 200°C.
After prepolymerizing for 0.5 to 48 hours, it can be charged into a desired mold and postpolymerized.

[0020] Furthermore, additives such as UV absorbers and anti-coloring agents may be added to these raw material monomers as necessary. Furthermore, various surface treatments can be performed after curing in order to improve the surface properties of the cured product.

[0021]

Effects of the Invention The optical resin of the present invention has a refractive index of 1.55 or more, a high Abbe number, small chromatic aberration and optical distortion, optical transparency, heat resistance, solvent resistance, and impact resistance. It also has excellent properties and has a low specific gravity, making it possible to reduce weight. In addition, there is no bad odor characteristic of sulfur compounds when charging and curing the monomer composition, and the monomer composition has a low viscosity, so it has excellent handling properties and is easy to control the reaction during curing polymerization and molding. So,
It is useful as a resin material for plastic lenses such as eyeglass lenses, camera lenses, and optical materials, or for other optical applications.

[0022]

EXAMPLES The present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0023]

Example 1 0.05 g of tert-butyl peroxybenzoate was added to and mixed with 10 g of the organic sulfur compound shown in Table 1 to obtain a monomer composition. Next, the monomer composition was poured into two glass molds, placed in a constant temperature bath at 80°C, heated at a curing temperature of 80°C for 6 hours, and further heated to 100°C for 3 hours to form the final mold. The mixture was heated at 100°C for 3 hours. Finally, an annealing treatment was performed at 100° C. for 2 hours to obtain a cured resin. The obtained cured resin was taken out from the mold, and the refractive index, Abbe number, b*
The value and heat resistance were measured according to the following method. The results are shown in Table 1.

-Refractive index and Abbe number: Measurements were carried out using an Abbe refractometer (manufactured by Atago Co., Ltd.) and a saturated methyl iodide solution as an intermediate solution.

b* value (yellowness): Measured using a photometer model 1001 manufactured by Nippon Denshoku Industries Co., Ltd. Note that the smaller this value is, the lower the degree of yellowness is, and the better.

Heat resistance: No deformation or discoloration in an oil bath at 130° C. was rated as ○, and those with deformation or discoloration were rated as ×.

[0027]

Examples 2 to 8 Cured resins were prepared in the same manner as in Example 1, except that the raw material monomers shown in Table 1 were used, and each measurement was performed. The results are shown in Table 1.

[0028]

[Table 1]

[0029]

[Comparative Examples 1 to 3] Cured resins were prepared in the same manner as in Example 1, except that the monomers shown in Table 2 were used, and various measurements were conducted. The results are shown in Table 2.

[0030]

[Table 2]

Claims (1)

[Claims] [Claim 1] The following general formula 1 (in the formula, R is CH2=
An optical resin obtained by polymerizing a raw material monomer containing an organic sulfur compound represented by CH or CH2CH=CH2, and X represents a hydrogen atom or a methyl group. [Chemical formula 1]