JPH0493309A - Optical resin - Google Patents

Abstract

PURPOSE:To provide a low-specific-gravity optical resin having a high refractive index, low chromatic aberration and optical strain, and excellent optical transparency, heat resistance, solvent resistance, impact resistance, etc., by polymerizing a monomer mixture containing a specifiec organosulfur compound. CONSTITUTION:An optical resin is produced by polymerizing a monomer mixture containing an organosulfur compound of formula I (wherein n is 2 or 3), e.g. a compound of formula II, and optionally a comonomer (e.g. styrene or methyl methacrylate). This resin can be desirably used for plastic lenses such as spectacle lenses or camera lenses. The compound of formula I can be easily produced, for example, by reacting 3mol equivalent of divinylbenzene with one mol equivalent of 1,2-dimercaptoehtane in the presence of, e.g. tert-butyl peroxybenzoate as a catalyst.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an optical resin, and more specifically, to a refractive index,
This invention relates to optical resins that have excellent optical properties such as chromatic aberration and transparency, and various mechanical properties.

<Prior Art> In recent years, synthetic resin materials that are lightweight, easy to mold, have excellent impact resistance, dyeability, etc. have been used as plastic 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 polymethyl methacrylate and polydiethylene glycol bisallyl carbonate are lightweight and have excellent impact resistance, they have a low refractive index of about 1.49, so when used as lenses, they require thicker lenses than inorganic glasses. The drawback is that it is not suitable for high magnification and weight reduction. Furthermore, although the refractive index of polystyrene and polycarbonate is as high as about 1.58 to 1.59, since these are thermoplastic resins, there is a problem that optical distortion due to birefringence is likely to occur during injection molding. However, it also has drawbacks such as lack of solvent resistance and scratch resistance.

Therefore, in recent years, several technical proposals have been made to improve these conventional drawbacks with 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 proposes a high refractive index optical resin obtained by reacting a dimercaptobenzene nuclear substitute with a compound having at least two reactive unsaturated groups per molecule. .

<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 and are poor in handling.
There are also problems with the working environment.

Furthermore, optical resins obtained by polyaddition and polycondensation have drawbacks such as poor yields because it is difficult to control the polymerization reaction.

Therefore, the object of the present invention is to create a resin that has desirable refractive index, chromatic aberration, transparency, etc. for plastic lenses or other optical resins, has excellent various mechanical properties, has low odor, and has excellent handling properties when cured. Means for Solving the Problems in Providing an Optical Resin> According to the present invention, a compound represented by the following general formula (I) (1) (wherein n represents 2 or 3) An optical resin obtained by polymerizing a raw material containing an organic sulfur compound is provided.

The present invention will be explained in more detail below.

The optical resin of the present invention is characterized by containing a specific organic sulfur compound as an essential raw material.

The organic sulfur compound used as an essential raw material in the present invention can be represented by the following general formula (I), (1) where n represents 2 or 3.

As the organic sulfur compound represented by the general formula (I),
For example, these compounds can be used alone or as a mixture.

To prepare the organic sulfur compound, for example, 3 molar equivalents of divinylbenzene and 1,2-dimercaptoethane
1 molar equivalent, preferably from -10 to +8 in the presence of tertiary-butylperoxybenzonate or the like as a catalyst.
It can be easily obtained by reacting at 0°C for 1 to 24 hours. In addition, at this time, divinylbenzene is para body,
Meta forms or mixtures thereof can be used.

Further, the blending ratio of the organic sulfur compound to the entire raw material monomer is not particularly limited, but is preferably in the range of 1 to 100% by weight, particularly preferably 50 to 100% by weight based on 100% by weight of the raw material monomer. .

In the present invention, examples of compounds other than the organic sulfur compounds that can be used as raw material components include styrene, p-methylstyrene, p-chlorostyrene, and 0-chlorostyrene.

p-bromustyrene, 0-bromustyrene, vinyl acetate, vinyl propionate, methyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, phenyl methacrylate, phenyl acrylate, benzyl acrylate, benzyl methacrylate, bromphenyl methacrylate, acrylonitrile, methacrylaterile, 2,2-bis(4-methacryloyloxyethoxyphenyl)propane, 2,2-bis(4-
Acryloyloxyethoxyphenyl) propane, diethylene glycol bisallyl carbonate, diallyl tetrachlorophthalate, diallyl phthalate, divinylbenzene, divinylbiphenyl, ethylene glycol bis methacrylate, diethylene glycol bis methacrylate, ethylene glycol bis acrylate, diethylene bis acrylate, dipropylene glycol bis methacrylate , triethylene glycol bisacrylate, tetraethylene glycol bisacrylate, bisphenol A bismethacrylate, diallyl tetrachlorophthalate, diallyl isophthalate, allyl methacrylate, propylene glycol bisacrylate, hexaethylene glycol bisacrylate, octaethylene glycol bisacrylate, decane ethylene Preferable examples include glycol bisacrylate and the like.

To prepare the high refractive index optical resin of the present invention, for example,
It can be obtained by heating or copolymerizing each of the raw material monomers in the presence of a radical polymerization initiator.

The radical polymerization initiator has a 10-hour half-life temperature of 16
Organic peroxides or azo compounds having a temperature of 0°C or lower can be used, and specifically, for example, benzoyl peroxide, diisopropyl peroxydicarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, tert-butyl peroxydiisobutyrate, lauroyl peroxide, t-butyl peroxy acetate, tert-peroxy octoate, tert-butyl peroxybenzoate, azobisisobutyronitrile, etc., which may be used alone or in mixtures. It can be used as 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 may be directly charged into a desired mold, and the polymerization may be carried out by heating preferably at 0 to 200°C for 1 to 48 hours. can. At this time, the polymerization system is 1
For example, it is desirable to carry out under an inert gas atmosphere such as nitrogen, carbon dioxide, or helium. In addition, before the polymerization, the raw material monomers are heated at 0 to 20°C and 0.5 to 48°C, for example.
After prepolymerizing for a period of time, it can be charged into a desired mold and post-polymerized.

Moreover, additives such as a UV absorber and a coloring inhibitor can 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.

<Effects of the Invention> The optical resin of the present invention has a refractive index of 1.55 or more,
Moreover, it has small chromatic aberration and optical distortion, and is excellent in optical transparency, heat resistance, solvent resistance, and impact resistance, and furthermore, it has a small specific gravity and can be lightweight. In addition, there is no bad odor characteristic of sulfur compounds when preparing and curing the 7-summer composition, and it is easy to handle, and reaction control and molding during curing polymerization are easy, so it can be used in glasses lenses, camera lenses, optical It is useful as a resin material for plastic lenses and other optical applications.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

11L 0.05 g of tert-butyl peroxybenzoate was added and mixed to a raw material mixture consisting of 8 g of the organic sulfur compound shown in Table 1 and 2 g of diethylene glycol dimethacrylate to obtain a monomer composition. Next, the monomer composition was placed in two glass molds, placed in a constant temperature bath at 80°C, heated at a curing temperature of 80°C for 6 hours, and then heated for 3 hours.
The temperature was raised to 100°C over an hour, and finally 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 its refractive index, Abe's number, 5-point value, and heat resistance were measured according to the following methods. The results are shown in Table 1.

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

- 5-point value (yellowness): Measured using 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: Those with no deformation or discoloration in an oil bath at 130°C were rated O1, and those with deformation or discoloration were rated X.

A cured resin was prepared in the same manner as in Example 1, except that the raw materials shown in Table 1 were used, and each measurement was performed.

The results are shown in Table 1.

A cured resin was prepared in the same manner as in Example 1, except that the seven-layer resin shown in Table 2 was used, and each measurement was performed. The results are shown in Table 2.

Claims (1)

[Claims] A raw material monomer containing an organic sulfur compound represented by the following general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼...(I) (in the formula, n indicates 2 or 3) Optical resin obtained by polymerizing.