JPH0315721B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to lenses made of plastic, and more particularly to three-dimensionally crosslinked high refractive index plastic lens materials. Plastic lenses are becoming widely used in optical products due to their ease of molding and light weight. Among these, the weight of the entire spectacle lens has a great influence on both the physiology and the optics of the spectacle lens, and it is desirable that the lens be light. For such reasons, plastic eyeglass lenses have become popular in recent years. The resins that make up the mainstream of spectacle lenses currently in use are:
It is CR-39 and can reduce the weight of the lens to half that of inorganic glass. However, since the refractive index of CR-39 is 1.49 to 1.50, compared to inorganic glass lenses, CR-39 lenses have a lower center thickness, edge thickness,
Also, the curvature tends to be large, so a plastic with a high refractive index is desired. Very familiar resins with high refractive index include polycarbonate (nD 1.58) and polystyrene (nD 1.60). All of these are two-dimensional polymers and are thermoplastic, so they are difficult to post-process for items with a wide variety of designs, such as eyeglass lenses, and are used in some safety glasses and cheap sunglasses. There are only Prior art related to the present application includes JP-A No. 53-89752, JP-A No. 54-110853, and JP-A No. 51-Sho.
81589, Patent application 1986-145434, Patent application 1977-107948,
There is a patent application filed in 1984-1458 and a patent application published in 1974-13747. However, there has been no dramatic technological progress in either case. The present invention is based on these techniques, and as a result of experiments, a three-component system that can be put to practical use has been derived. That is, the plastic eyeglass lens of the present invention is made by copolymerizing a mixed monomer consisting of 50 to 70% by weight of the monomer represented by the general formula and the remainder consisting of the monomer represented by the general formula. Features.

(In the formula, m is an integer of 1, 2, 5) (In the formula, M is La, Ti, Zr, Pb, Ta, Cu, Zn,
By using one of Sn, Cr, Tl, and Th (m represents the valence of the metal), the plastic eyeglass lens of the present invention contains a halogen styrene derivative in the repeating unit of the polymer, so it has a refractive index. A spectacle lens with a high refractive index of 1.65 or more can be obtained, and since the repeating unit of the polymer contains a polyfunctional diacrylate having an M-O bond, conventional methods can be used to process it into a lens shape. It enables grinding using a commonly used diamond grindstone and has improved scratch resistance and weather resistance.

Example 1 Precision distillation of commercially available ortho-chlorostyrene,
A commercially available product with non-polymerizable impurities reduced to 0.01% or less contained approximately 2.5% non-polymerizable substances based on composition analysis by gas chromatography. Although it is called ortho-chlorostyrene, it contains para-chlorostyrene at a ratio of 3:1, but for convenience, ortho-chlorostyrene is
Described as chlorostyrene. 55 parts of this purified ortho-chlorostyrene and the general formula
35 parts of lanthanum trimethacrylate in which R ₁ is a methyl group and m is 3 were mixed and stirred. Furthermore, the polymerization initiator IPP (diisopropyl peroxydicarbonate) was diluted to 0.0006 parts.
10 parts of chlorostyrene was added and heated at 60° C. for 1 hour and 30 minutes to carry out preliminary polymerization. The viscosity of the mixed monomer before prepolymerization was 3 CPS, but the viscosity at room temperature after heating was 83 CPS, which was a viscosity suitable for injection. 1.0 part of diisopropyl peroxydicarbonate was added to and mixed with the above monomer, and the monomer that had passed through the filter was filled into the casting jig shown in FIG. 1 under pressure. In Fig. 1, 1 is a gasket manufactured by injection molding of a copolymer of ethylene-ethyl acrylate, 2 and 2' are optically polished glass molds, 3 is a presser spring that presses down the upper and lower glass molds, and 4 is a gasket that is filled with monomer. show. The jig thus set was immersed in hot water to carry out hot water polymerization. The conditions at this time were: held at 40°C for 10 hours, then linearly raised to 90°C over 34 hours, held at 90°C for 3 hours, then lowered to 60°C, and the lens was removed from the molded glass. Thereafter, it was heated in a hot air oven at 100°C for 45 minutes for secondary curing. When the refractive index was measured, it was 1.653.

Example 2 A lens was manufactured in exactly the same manner as in Example 1 except that dichlorostyrene was used instead of ortho-chlorostyrene. The refractive index of the lens material was 1.664.

Example 3 A lens was manufactured in the same manner as in Examples 1 and 2 except that pentachlorostyrene was used in place of the ortho-chlorostyrene used in Example 1. The refractive index of the lens material is 1.673
It was a little pale yellow, but after dyeing it,
By adding an anti-reflection coating, the color tone did not pose any practical problems.

M in the general formula is not La, but for example Ti, Zr,
Similar lens characteristics can be obtained with Pb, Ta, Cu, Zn, Sn, Cr, Tl, and Th, and the larger the number of m, the more the lens itself has plastic-like characteristics. If too many general formulas are added, the plastic lens will break easily and the performance of the plastic lens will not be fully demonstrated. However, the more m there is, the more plastic properties remain in proportion to the amount. An organometallic compound having an M--O bond is an essential component in this lens composition. We investigated properties other than refractive index, such as scratch resistance, heat resistance, grindability, and ease of dyeing.
It had the same level of performance as the CR-39 lens that is currently mainly used, and the organic hard coat and inorganic antireflection coating on the lens had quality characteristics that could be put to practical use. Properties of these lens materials can be improved by adding ultraviolet absorbers and antioxidants. Halogenated styrene is good in terms of material cost and lens properties such as obtaining a high refractive index when it is in the range of 50 to 70% by weight; when it is less than 50%, the proportion of other materials increases, resulting in high costs. In addition, if it is 70% or more, heat resistance will be poor, making it difficult to perform hard coat film treatment or anti-reflection film treatment that requires post-processing, and the quality of the coat film will deteriorate in terms of durability.
It is inferior to 39 and is not preferred as a lens material.
As described above, the present invention is novel and at the same time has industrial value.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a mold set for manufacturing lenses. 1... Soft resin gasket, 2, 2'... Glass type, 3... Pressure spring.

Claims (1)

[Claims] 1. 50 to 70% by weight of a monomer represented by the general formula,
A plastic eyeglass lens characterized in that it is made by copolymerizing a mixed monomer, the remainder of which is a monomer represented by the general formula. (In the formula, m is an integer of 1, 2, 5) (In the formula, M is La, Ti, Zr, Pb, Ta, Cu, Zn,
One of Sn, Cr, Tl, and Th, where m represents the valence of the metal).