JPH01197528A - Composition for lens of high refractive index - Google Patents

Abstract

PURPOSE:To make it possible both to provide a resin having a high refractive index, a low specific gravity and excellent impact resistance after curing and to form a compsn. for a plastic lens having a good storage stability, by compounding a specified thiol compd. with divinylbenzene in a specified ratio. CONSTITUTION:This compsn. comprises divinylbenzene and a thiol compd. having two or more aliph. -SH groups in the molecule and the molar ratio of the total vinyl groups to the total -SH groups is in the range of 1 or larger and 10 or smaller. The thiol compd. is pref. one or more compd. selected from among trimethylolpropane tris(thioglycolate), trimethylolpropane tris(beta-thiopropiona te), pentaerythritol tetrakis(thioglycolate) and pentaerythritol tetrakis(beta- thiopropionate).

Description

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

(Conventional technology and its problems) Poly(diethylene glyfur bis-7-lyl carbonate) is a typical curable resin that has been put into practical use for plastic lenses, and it has good impact resistance, is lightweight, and has excellent dyeability. Therefore, it is often used as a resin for plastic lenses for vision correction glasses.

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, as a lens for spectacles, it is desired that the green thickening of the lens be thin and that there be 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 resin for lenses having a sufficiently higher refractive index than poly(diethyreglycol bis7lyl carbonate) is desired.

As a resin for high refractive index lenses, a resin obtained by the reaction of a hydroxy compound containing a bromine atom with incyanate (JP-A-58-164615 4fi) and a reaction between a polyol compound containing an 11ε yellow atom and a polyisocyanate. A number of proposals have been made, including resins obtained by JP-A-60-217229 and resins made of aromatic acrylic compounds containing bromine atoms (JP-A-57-104901).

However, when incyanate is used, the storage stability of the resin before curing is poor and it is easily affected by moisture in the air, and when an aromatic acrylic compound containing bromine atoms is used, the specific gravity of the resin is low. The disadvantage is that it gets bigger.

Furthermore, although divinylbenzene polymers are known resins, they have low impact resistance and are not practical.

(Means for Solving the Problems) The present inventors have developed a composition for plastic lenses that can be cured to provide a resin with a high refractive index, low specific gravity, and excellent impact resistance, and which has good storage stability. As a result of studying the matter, the present invention was arrived at.

That is, the present invention comprises divinylbenzene and a thiol compound having two or more aliphatic -SH groups in the molecule, and the molar ratio of total vinyl groups/total -SH groups in the composition is from 1 to 10. It is a composition for a high refractive index lens that has a range of .

The divinylbenzene used in the present invention includes industrially used para-divinylbenzene, meta-divinylbenzene, or a mixture thereof. The thiol compound having c2 or more aliphatic -3H groups in the molecule refers to a compound containing two or more -CH2SH, -CH3I or triC3H groups in one molecule.

For example, ethylene glycol dithioglycolate, ethylene glycol dithiopropione), 1,4-butanedioldithioglycolate), 1,4-butanediol dithiopropionate, trimethylolpropane tris(β-thioglycolate) ), trimethylolpropane tris (β-thiopropionate), pentaerythritol tetra-wound (β-thioglycolate), pentaerythritol tetra-wound (β-thiopropionone-)), 1,
2-dimercaptoethane, 1.2.3-)rimercaptopropane, 1,4-bis(mercaptomethyl)benzene, 1,3°5-tris(mercaptomethyl)benzene,
Examples include 2-methyl-1,2-dimercaptopropane.

Particularly preferred are trimethylolpropane tris (thioglycolate), trimethylolpropane tris (β-
Mention may be made of the thiol compounds selected from thiol compounds such as thiopropionate), pentaerythritol tetrawound (thioglycolate), and pentaerythritol tetrawound (β-thiopropionate). Note that these thiol compounds can be used alone or in combination.

The blending ratio of divinylbenzene and the thiol compound having two or more aliphatic -3H groups in the molecule in the composition is such that the molar ratio of total vinyl groups/total -SH groups in the composition is 1 or more and 1 or more.
It is blended so that it is in the range of 0 or less, and more preferably in the range of 2 or more and 6 or less.

If the blending ratio is less than the above-mentioned ratio, the composition will not be sufficiently cured and the strength of the cured product will be insufficient. If the mixing ratio exceeds the above range, the specificity of the optical properties of the resulting cured product will be lost and the strength 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, but the radical polymerization initiator used in this case can be used as long as it generates radicals by heating, ultraviolet rays, or electron beams. benzoyl oxide,
Examples include thermal polymerization catalysts such as diisopropyl peroxycarbonate and azobisin butyronitrile, and photopolymerization catalysts such as benzophenone, benzoin and benzoin methyl ether.

The amount of the radical polymerization catalyst 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% based on the total amount of the composition, preferably o,
oi% to 5.6 The present composition may contain radically reactive compounds such as styrene, ethylstyrene, claustyrene, trimethylolbubantris (acrylate), 'pentaerythritol tetrakis (7cryl)), ) can be diluted with a vinyl compound such as rimethylpropane tris(β-thioglycolate), but in that case, all vinyl groups/all-S
The molar ratio of H groups needs to be in the range of 1 or more and 10 or less.

Furthermore, it is of course possible to improve the practicality of the resulting resin by adding known additives such as antioxidants, ultraviolet absorbers, or polymerization inhibitors 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, the mixture is poured into a glass or metal mold, the polymerization reaction is advanced by heating or ultraviolet irradiation, and the composition is removed from the mold after 0.1 to 24 hours. Furthermore, surface treatments such as hard coating, antireflection, and antifogging properties are performed as necessary.

(Effects of the Invention) The lenses obtained by polymerizing and curing the composition of the present invention are colorless and transparent, have a high refractive index, a high stain count, and have a small specific gravity, are light, have good impact resistance, and are heat resistant. It has characteristics such as excellent polishability and processability such as polishability. Furthermore, since the composition has characteristics such as good storage stability, it can be used in various applications as an optical material, and is particularly suitable for use in plastic lenses for eye bonds.

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

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

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

Impact resistance: Good if a 30g iron ball is dropped onto the cured product (disc of 60mm x 2.5mm thick) from a height of 1.27m and no cracking occurs.

Example 1 A composition consisting of 60 parts of metadivinylbenzene and 40 parts of pentaerythritol tetrakiz (β-thiopropionate) was added with barbutyl 0 (t-butylperoxy (2-ethylhexanoei)) as a polymerization initiator. 0.
5 parts were uniformly mixed, poured into a mold made of two pieces of glass and a rubber gasket, and heated from 50°C to 55°C for 10 hours, from 55°C to 65°C for 5 hours, and from 65°C to The temperature was linearly raised to 75°C for 2 hours and from 75°C to 100°C for 3 hours, and then held at 100°C for 1 hour to perform polymerization and curing.

The molar ratio of all vinyl groups/all -SH groups in the composition is 2.
．． It was 8.

Furthermore, no increase in viscosity was observed even when the composition was left at room temperature for 3 hours.

The obtained cured product is colorless and transparent, has a refractive index (ND) of 1°609 measured using a refractometer at 20°C, and has good optical properties with a high refractive index and a high Atsbe number of 32. had.

In addition, the specific gravity was light at 1.19, and the heat resistance and impact resistance were good, making it an excellent lens, especially as an eye lens.

Examples, 2 to 6 and Comparative Example 1 Similarly to Example 1, the compositions shown in Table 1 were polymerized and cured using Perbutyl 0 as a polymerization initiator. The obtained cured product was colorless and transparent. Table 1 shows the measured physical property values.

The abbreviations in the table indicate the following compounds.

mDVB: Metacyhinylbenzene RDvB: Commercially available reagent divinylbenzene (mixture containing meta, hala and ethylvinylbenzene 30?) TMTP: ) Limethylolpropane tris (β-thiopropionate) PETP: Pentaerythritol tetrakis ( β-Thiopropionate) PETG: Pentaerythritol Tetrakis (β-Thioglyflate) DME: 1,2-dimercaptoethane BMMB:
1.4-bis(mercaptomethyl)benzene

Claims (2)

[Claims] (1) A composition comprising divinylbenzene and a thiol compound having two or more aliphatic -SH groups in one molecule, wherein the molar ratio of total vinyl groups/total -SH groups in the composition is 1 or more and 10 or more. A composition for a high refractive index lens having the following range. (2) Thiol compounds include trimethylolpropane tris (thioglycolate), trimethylolpropane tris (β-thiopropionate), pentaerythritol tetra-wound (thioglycolate), and pentaerythritol tetra-wound (β-thiopropionate). 2. The high refractive index lens composition according to claim 1, wherein the composition is selected from the group consisting of: