JPH02306201A - Composition for high-refractive index plastic lens - Google Patents

Abstract

PURPOSE:To obtain the compsn. for plastic lenses having a high refrective index, small sp. gr. and excellent heat resistance and strength by specifying the compounding ratio of the arom. vinyl compd. expressed by specific formula and isocyanate compd. to a>=0.5 and <=2.0 range in the ratio of a hydroxyl group to an isocyanato group. CONSTITUTION:This compsn. consists essentially of the arom. vinyl compd. expressed by the formula I and the isocyanate compd. In the formula, R denotes 1 to 4C hydrocarbon. The ratio of the hydroxyl group and isocyanato group in the compsn. is required to be a>=0.5 and <=2.0 range. The heat resistance and strength, etc., are insufficient if the ratio is off this range. The more specific examples of the arom. vinyl compd. expressed by the formula I include the compds. expressed by formulas II, III, IV and the meta-isomers of these compds. and the mixtures, etc., thereof. A radical polymn. initiator is added to such cmpsn. and the compsn. is polymerized and cured. The compsn. formed in such a manner is used as optical materials for lenses, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a composition for high refractive index lenses that is suitable as an optical material, particularly as an optical lens material such as a plastic lens for eyelids.

(Conventional technology and its problems) The typical curable resin that has been put into practical use for plastic lenses is poly(diethylene glycol bisallyl carbonate), which has good impact resistance, is lightweight, and has excellent dyeability, so it improves visual acuity. It is often used as a resin for plastic lenses for corrective eyeglasses.

However, poly(diethylene glycol bisallyl carbonate) has the disadvantage of a low refractive index of 1.50, and cannot be said to have sufficient performance.

That is, for plastic lenses for eyeglasses, it is desired that the edge of the lens be thin and have little chromatic aberration. The higher the refractive index, the thinner the edge of the lens becomes, and the higher the Abbe number, the smaller the chromatic aberration.

Therefore, a lens resin having a refractive index sufficiently higher than that of poly(diethylene glycol bisallyl carbonate) is desired.

As a resin for high refractive index plastic lenses, a resin obtained by the reaction of a hydroxy compound containing a bromine atom with an isocyanate (Japanese Unexamined Patent Publication No. 164615/1989) or a resin obtained by a reaction between a polyol compound containing a sulfur atom and a polyisocyanate is used. Resin obtained (JP-A-60-21722
A number of proposals have been made, such as a resin made of an aromatic acrylic compound containing a bromine atom (Japanese Unexamined Patent Publication No. 104901/1983).

However, when an aromatic acrylic compound containing a bromine atom is used, there is a drawback that the specific gravity of the resin becomes large, and when a polyol compound and a polyisocyanate are used, there is a drawback that heat resistance is poor.

(Means for Solving the Problems) The present inventors have studied a composition for plastic lenses that can be cured to produce a resin with a high refractive index, low specific gravity, and excellent heat resistance and strength. reached.

That is, the present invention is a composition containing an aromatic vinyl compound represented by the general formula (1) and an isocyanate compound as essential components, wherein the ratio of hydroxyl groups to isocyanate groups in the composition is 0.5 or more and 2. This is a composition for a plastic lens with a high refractive index in the range of 0 or less.

(In the formula, R represents a hydrocarbon group having 1 to 4 carbon atoms. Specific examples of aromatic vinyl compounds represented by the above general formula (1) include H3, meta isomers of the above compounds, and mixtures thereof. Particularly preferred are mixtures of 3- or 4-vinylbenzyl alcohol and cholera, but the invention is not limited thereto.

Specific examples of isocyanate compounds include inphorone diisocyanate, hexamethylene diisocyanate, m-
Alternatively, p-xylylene diisocyanate, toluylene diisocyanate, phenylene diisocyanate, etc. can be mentioned, and particularly preferred isocyanate compounds include metaxylylene diisocyanate and hexamethylene diisocyanate, but are not limited to these.

The blending ratio of the aromatic vinyl compound represented by the general formula (1) and the isocyanate compound in the composition is such that the ratio of hydroxyl groups to isocyanate groups is in the range of 0.5 or more and 2.0 or less.

If it is outside the range, heat resistance, strength, etc. will be insufficient.

The composition of the present invention is polymerized by adding a radical polymerization initiator,
The cured product is used as an optical material such as the above-mentioned lenses. In this case, the radical polymerization initiator used can be one that generates radicals by heating, ultraviolet rays, or electron beams. For example, Examples include known thermal polymerization catalysts such as benzoyl peroxide, diisopropyl peroxycarbonate, and azobisisobutyronitrile, and known photopolymerization catalysts such as benzophenone, benzoin, and benzoin methyl ether.

The amount of radical polymerization catalyst blended varies depending on the components of the composition and the curing method, so it cannot be determined unconditionally, but it is usually 0.001% to 5%, preferably 0.001% to 5%, based on 1 hl of the composition.
．． The range is 0.01% to 5%.

In addition, a small amount of a known catalyst may be added to this composition in order to sufficiently advance the curing of the isocyanate compound and increase the strength of the cured product. Examples of catalysts include tin compounds such as dibutyltin silaurylate, zinc, lead,
Examples include metal compounds such as aluminum, titanium, and vanadium, and Lewis bases such as tertiary amines and tertiary phosphine.

The composition may contain radically reactive compounds such as styrene, chlorostyrene, divinylbenzene, trimethylolpropane tris(acrylate), pentaerythritol tetrakis(acrylate), ethylene glycol dimethacrylate, bis(2-acryloxyethoxyphenyl)propane, Methylolpropane tris (β-thioglycolate), trimethylolpropane tris (β-
thiopropionate), pentaerythritol tetrakis (β-thioglycolate), pentaerythritol tetrakis (β-thiopropionate), diallyl phthalate, triallyl in cyanurate, etc., but in that case Preferably, the amount of radically reactive compound to be diluted is 50% by weight or less of the composition.

Furthermore, it is of course possible to further improve the practicality of the resulting resin composition by adding known additives such as antioxidants and ultraviolet absorbers to the composition of the present invention.

As one example of its application, the composition of the present invention can be made into a lens in the following manner.

That is, a radical polymerization initiator is added to the composition, this is injected into a lens mold made of glass or metal, and the polymerization and curing reaction is proceeded by heating or irradiation with ultraviolet rays or electron beams.
After 1 to 24 hours, remove the mold.

Furthermore, surface treatments such as hard coating, antireflection, and antifogging properties are performed as necessary.

(Effects of the Invention) Lenses obtained by polymerizing and curing the composition of the present invention are colorless and transparent, have a high refractive index, and have a high Shimatsube number. In addition, it has characteristics such as low specific gravity, light weight, excellent workability such as polishing properties, excellent heat resistance, and good dyeability. Furthermore, the composition of the present invention can be used for various purposes as an optical material, and is particularly suitable for use in plastic lenses for eyewear.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

The heat resistance and ionic impact resistance of the cured product were evaluated by the following methods.

Heat resistance; heat softening temperature of cured product (load IV4)
A case where the temperature is 120°C or higher is considered good.

Impact resistance: 1.2 for cured product (60 mm x 2.5 thickness)
A case where a 309 iron ball was dropped from a height of m and did not break was considered good.

Example 1 Mixture of 3-vinylbenzyl alcohol and 4-vinylbenzyl alcohol 359, m − + silylene diisocyanate 259, styrene 409, perbutyl 0 (t-
Butyl peroxy (2-ethylhexanoate))
0.29 and dibutyltin dilaurate 50ppm
The mixture was uniformly mixed and injected into a mold made of two pieces of glass and a rubber gasket, and heated from 40℃ to 110℃ for 1 hour.
After increasing the temperature linearly for 6 hours, the temperature was maintained at 110° C. for 2 hours to carry out a polymerization curing reaction. The obtained cured product is colorless and transparent, and has a refractive index (20°C) of 1.60 as measured by an Atsube refractometer.
The Atsube number was 31, and the specific gravity was 1.16, making it lightweight. It also had good heat resistance and impact resistance, and was excellent as a lens, especially a high refractive index plastic lens for limit value use.

Example 2 4-vinylbenzyl alcohol 359, m-xylylene diisocyanate 259, chlorstyrene (o/
P mixture) 409, perbutyl OO, 2,9 and dibutyl tin dilaure) 50 ppm were mixed uniformly and heated from 60°C to 110°C in the same mold as in Example 1.
After increasing the temperature linearly to 100°C for 16 hours, the temperature was maintained at 100°C for 1 hour to perform a curing reaction. The obtained cured product was colorless and transparent, had a refractive index (20° C.) of 1.61, an Atsube's number of 31, and a specific gravity of 1.26, which was lightweight.

Furthermore, the heat resistance and impact resistance were also good.

Claims (2)

[Claims] (1) A composition containing an aromatic vinyl compound and an isocyanate compound represented by the general formula [I] as essential components, ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (wherein R is carbon A composition for a high refractive index plastic lens, wherein the ratio of hydroxyl groups to isocyanate groups in the composition is in the range of 0.5 or more and 2 or less. (2) R in general formula [I] is -CH_2-, -CH_2
The composition for a high refractive index plastic lens according to claim 1, which is CH_2- or ▲ has a mathematical formula, chemical formula, table, etc. ▼.