JPH0312281B2 - - 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, in the case of eyeglass lenses, the weight of the whole eyeglasses has a great effect on both the physiology and the optics of the eyeglasses, and it is desirable that the lenses 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 post-processing is difficult for products with various designs such as eyeglass lenses, and some are used in 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, has derived a three-component system that can be put to practical use. That is, the plastic eyeglass lens of the present invention consists of 50 to 70% by weight of the monomer of the chloride derivative of styrene represented by the general formula, and the remainder of the monomer having the benzene nucleus represented by the general formula. It is characterized by being copolymerized with a mixed monomer consisting of an acrylate monomer and an allyl cinnamate monomer represented by the general formula, where the monomer represented by the general formula is 5% by weight or more. shall be.

(In the formula, m is an integer of 1, 2, or 5) (In the formula, M is La, Ti, Zr, Pb, Ta, Cu, Zn,
One of Sn, Cr, Tl, Th, m represents the valence of the metal) (In the formula, X represents hydrogen, Cl, or Br.) Since each repeating unit of the polymer contains the monomer represented by the general formula, A spectacle lens with a refractive index can be obtained, and since it contains a monomer represented by the general formula and, it can be ground with a diamond grindstone, which has been conventionally commonly used to process the lens shape. It has improved scratch resistance and weather resistance.

This will be explained below using examples.

Example 1 Precision distillation of commercially available orthochlorostyrene,
Non-polymerizable impurities were reduced to 0.01% or less. Composition analysis by gas chromatography revealed that the commercially available product contained about 2.5% non-polymerizable substances. Although it is called ortho-chlorostyrene, it contains para-chlorostyrene in a ratio of 3:1, but for convenience it is referred to as ortho-chlorostyrene. 55 parts of this purified orthochlorostyrene and the general formula
35 parts of lanthanum trimethacrylate in which R1 is a methyl group and m is 3, and 10 parts of allyl cinnamate represented by the general formula were mixed and stirred. Furthermore, the polymerization initiator I.
PP (diisopropyl peroxydicarbonate)
10 parts of orthochlorostyrene diluted to 0.0006 parts was added, and the mixture was heated at 60°C for 1 hour and 30 minutes to carry out prepolymerization. The mixed monomer viscosity before prepolymerization was 3 cps, but the viscosity at room temperature after heating was 1090 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 made of ethylene-ethyl acrylate copolymer by injection molding, 2 and 2' are optically polished glass molds, 3 is a presser spring that presses the upper and lower glass molds,
4 indicates loaded monomer. The jig thus set was immersed in hot water to carry out hot water polymerization. At this time, the conditions were kept at 40℃ for 10 hours, and then
The temperature was raised linearly to 90°C over 34 hours, held at 90°C for 3 hours, and 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 1.633.

Example 2 A lens was manufactured in exactly the same manner as in Example 1 except that dichlorostyrene was used instead of orthochlorostyrene. The refractive index of the lens material was 1.647.

Example 3 A lens was manufactured in the same manner as in Examples 1 and 2 except that pentachlorostyrene was used instead of orthochlorostyrene in Example 1. The refractive index of the lens material is 1.662
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, and Tl, and the larger the number of m, the more the lens itself has plastic-like characteristics. Even if a protective coating film is applied, the plastic lens will get scratched while being carried, and if a large amount of general formula is used, it will easily break, 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. Allyl cinnamate represented by the general formula itself has a refractive index of 1.58 even without halogen, and by introducing Cl or Br into the benzene nucleus,
You can get a value of 1.60 or more. Experiments have shown that adding 5% or more of this allyl ester facilitates polymerization, making it possible to form strong lenses that would be difficult to manufacture with the two components of general formulas () and (). As a cause,
It is considered that because of the good mutual adhesion with the glass mold, there was no separation from the mold during polymerization (the mold and polymer peeled off, resulting in a defective lens). It is an essential component in this lens composition. When we investigated properties other than refractive index, such as scratch resistance, heat resistance, grindability, and ease of dyeing, we found that it has the same level of performance as the CR-39 lens, which is currently mainly used. The organic hard coat and inorganic antireflection coating also had quality characteristics that could be put to practical use. Properties of these lens materials can be improved by adding ultraviolet absorbers and antioxidants. In terms of material cost, halogenated styrene is in the range of 50 to 70% by weight.
It is good in terms of lens properties as it can provide a high refractive index, but if it is less than 50%, the proportion of other materials will increase and the cost will increase. If it is 70% or more, the 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 be inferior to CR-39 in terms of durability, making the lens Not desirable as a 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,
The remainder consists of a monomer represented by the general formula and a monomer represented by the general formula, and the monomer represented by the general formula is made by copolymerizing a mixed monomer in which the monomer represented by the general formula is 5% by weight or more. Characteristic plastic eyeglass lenses. (In the formula, m is an integer of 1, 2, or 5) (In the formula, M is La, Ti, Zr, Pb, Ta, Cu, Zn,
Any one of Sn, Cr, Tl, Th, m represents the valence of the metal WO) (In the formula, X represents hydrogen, Cl, or Br)