JPS58164608A - Resin for plastic lens - Google Patents

Abstract

PURPOSE:The titled resin capable of forming lenses having excellent impact resistance and bending elasticity and a high refractive index, comprising a polymer prepared by addition-polymerizing a vinyl monomer compound mixture containing a (meth)acrylic acid metal salt. CONSTITUTION:A resin for plastic lenses, comprising a polymer prepared by addition-polymerizing a vinyl monomer compound containing above 30wt% (meth)acrylic acid metal salt of the formula, wherein X is H or CH3 and M is a metal, e.g., Pb, Ba, Zn or Al. Tough plastic lenses having a relatively low shrinkage during molding, and a high refractive index and excellent impact resistance and bending elasticity can be obtained and the size or thickness reduction of a lens is possible because of a high refractive index.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin for eyeglass plastic lenses.

Plastic lenses have the advantage of being easier to manufacture than glass lenses, and are also lightweight and have good impact resistance, making them highly safe when used in eyeglass lenses. Conventional plastic lens resins include acrylic resin, polycarbonate resin, allyl diglycol carbonate resin, and polystyrene resin. Among these, which plastic lenses are widely used for vision correction glasses.

Diethylene glycol bisallyl carbonate is a thermosetting resin. This resin has excellent impact resistance, and the lens power does not change significantly with changes in temperature.
Furthermore, it has various features such as good machinability and workability.

However, diethylene glycol bisallyl carbonate has a refractive index of 1.50, and when this resin is used as a lens, there is a drawback that the lens is thicker than a glass lens. This is particularly noticeable when the lens power increases.

In particular, in recent years, there has been a demand for plastic lenses to be smaller and thinner, and there has been a need for resins for plastic lenses that have a high refractive index that makes this possible.

The inventors of the present invention solved the above-mentioned problems and conducted extensive studies on resins for plastic lenses that provide a high refractive index, and as a result, they arrived at the present invention described below.

That is, the present invention relates to a resin for plastic lenses characterized by being made of a polymer obtained by addition polymerization of a vinyl monomer compound containing at least 60% by weight of a metal compound represented by the following general formula: It is.

OH,=O-0-0-M-0-0-C! = OH.

(X is hydrogen or methyl group 9M is metal) The compound of the above general formula used in the present invention is a metal salt of acrylic acid or methacrylic acid. Regarding the type of metal, in order to increase the refractive index, metals with a large atomic weight are preferred; metals that easily react with water and air, metals that are unstable to light, and metals that are radioactive are not preferred.

Examples of suitable metals include lead, bismuth, and 1□ Lium, barium, tin9. ? luconium, zinc.

These include phosphorus and aluminum.

On the other hand, the vinyl monomer used together with the metal salt mentioned above in the present invention may be any vinyl monomer as long as it is copolymerizable. However, the vinyl monomer is a colorless and transparent liquid,
Also, those that dissolve metal salts are preferable. For example, the following vinyl monomers are suitable.

Acrylic acid 1-Tacrylic acid Acrylic acid-2-Hydroxyethyl Methacrylic acid-2-Hydroxyethyl diallyl chlorendate Dimethallyl chlorendate Additionally, the following vinyl monomers are used in combination with the above vinyl monomers. You can also. Examples of such vinyl monomers include the following.

Styrene・ diallyl phthalate Ethylene ylicol dimethacrylate Methyl methacrivate , :.

The content of the metal salt of acrylic acid or methacrylic acid used in the present invention is at least 30% by weight in the polymer in order to increase the refractive index to at least 1.55. is necessary.

A general explanation of the method for manufacturing a plastic lens using the resin for plastic lenses of the present invention is as follows.

Manufacturing methods are broadly divided into cast polymerization and injection molding.

The feature of the cast polymerization method is that it directly polymerizes and hardens the raw material monomer and simultaneously forms it into a lens shape. Therefore, the lenses have little molding distortion and are characterized by excellent optical uniformity, and it is said that most prescription lenses made of plastic on the market are currently made using this method.

On the other hand, injection molding is a method in which pre-polymerized resin is injected into the shape of a lens, and methacrylic resin and polycarbonate resin are manufactured using this method for sunglasses and fashion glasses. In injection molding, it is necessary to ensure that the lens molded product has little optical distortion.
Mold design and molding condition settings are important issues.

Usually, a polymerization initiator is added, the reaction is preliminarily allowed to proceed to some extent (prepolymerization), dissolved gases such as air are degassed under vacuum, and then the mixture is poured into a mold and polymerized by heating.

The heating temperature is such that the reaction is initially carried out at a relatively low temperature (for example, 40 to 50 degrees Celsius), and as the reaction progresses, the temperature is increased to about 11 [1 degrees Celsius, for slow addition polymerization, which reduces distortion of the lens. preferable.

Various known polymerization initiators can be used, but should be selected depending on the desired reaction temperature. For example, 1,1-azobiscyclohexane carbonate, diimpropyl peroxycarbonate, 1,1/-azobiscyclohexane nitrate, di-tert-butyl peroxide, and the like are suitable.

The plastic lens containing the resin of the present invention as a resin component has the following characteristics compared to commercially available plastic lenses.

1. A strong plastic lens can be obtained.

2. Excellent impact resistance.

3. A colorless and transparent resin is obtained.

4. The shrinkage rate during molding polymerization is relatively small.

5. High refractive index.

6. Excellent bending elasticity.

1) Plastic lenses containing the resin of the present invention as a resin component can be subjected to surface modification such as anti-reflection, high hardness, abrasion resistance, improved chemical resistance, and anti-fogging properties using known physical or chemical methods. It is possible to apply the method.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that the refractive index in Example 0 is a value at a wavelength of 5892.9 AOD line.

Example 1 80 parts by weight of lead salt of acrylic acid: and acrylic acid-2
- Mix 20 parts by weight of hydroxyethyl to create a homogeneous solution. To this mixed solution, 1 part by weight of di-tert-butyl peroxide was added as a radical polymerization initiator,
After uniformly mixing, pour into a lens mold and heat at 80°C for 3 hours and at 100°C for 15 hours.

Thereafter, it was heat treated at 110°C for 1 hour.

The obtained polymer molded product is colorless, transparent, hard, and has a refractive index of 1.
．． It was extremely high at 61.

Example 2 70 parts by weight of barium salt of methacrylic acid, 10 parts by weight of diallyl crocindate, and 20 parts by weight of acrylic acid were uniformly mixed to dissolve the metal salt.

1 part by weight of diisopropyl peroxy carbonate as a polymerization initiator was added to this mixed solution and mixed uniformly. Pour this solution into a lens mold and hold it at 50'0 for 3 hours.
Heating was continued for 3 hours at 50°C, 6 hours at 50°C, and 10 hours at 60°C.

The obtained polymer molded product is transparent and hard, and has a refractive index of 1.60.
It was expensive. : Yu'5゜

Claims (1)

[Claims] (1) A resin for plastic lenses, characterized by comprising a polymer obtained by addition polymerization of a vinyl monomer compound containing at least 30% by weight of a compound represented by the following general formula. (X is hydrogen or methyl group 1M is metal)