JPS58105103A - Plastic lens - Google Patents

Abstract

PURPOSE:To obtain high in refractive index by polymerizing bromoalkyl methacrylate. CONSTITUTION:Hydrogen atoms of the alkyl group of alkyl methacrylate including methyl methacrylate represented by structural formula (I) are replaced by bromine atoms to give bromoalkyl methacrylate having structural formula (II), and this monomer is polymerized with a polymn. initiator, such as t-butyl peroxybenzoate or benzoyl peroxide, or a photopolymn. initiator, such as acetophenone, to prepare a plastic lens. Refractive index of the obtained polymer depends upon the kinds of bromoalkyl groups, and it is in the range of 1.493- 1.568.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic lens, particularly a plastic lens with a high refractive index.

Plastic lenses have become widely used in optical products because they are lighter than traditional glass lenses, have the potential for mass production, and are expected to be low cost. There is. The materials currently mainly used as plastic lens materials are:
For cast molding, there are diethylene glycol bisallyl carbonate and methyl methacrylate called acrysilabu as the main ingredients.For single molding, polymethyl methacrylate, polycarbonate, etc. are generally used. Compared to conventional glass lenses for molding, there are far fewer types of materials in practical use. Moreover, in the case of glass lenses, there is a wide range of refractive indexes, from low to high, and there is a considerable range in terms of dispersion, whereas plastic lens materials have a small number of types and have a refractive index of 1. 49～
The width is approximately 1.5o, which is extremely narrow compared to glass lenses. This poses a major problem when designing lenses. For example, in the case of eyeglass lenses, the refractive index is smaller than that of glass lenses, so the center thickness and curvature are larger, giving the user a different impression from the appearance than traditional glass glasses. .

Other examples include camera lenses, microscope lenses, etc.
A method to eliminate various aberrations such as chromatic aberration, spherical aberration, and coma aberration is to combine lenses with different refractive indexes and dispersions, but this method is difficult to use when using plastic lenses because there are few types. That's funny. I”
In addition to the currently used plastic lens materials (diethylene glycol bisallyl carbonate, polymethyl methacrylate, etc.), plastic lenses with various refractive indexes and dispersions are strongly desired. There is.

In view of these points, the present invention has added requirements such as having surface impact resistance equivalent to that of a plastic lens obtained by polymerizing alkyl methacrylate, being transparent and capable of cast molding, and The present invention provides a plastic lens having a higher refractive index than plastic lenses made of diethylene glycol bisallyl carbonate or methyl methacrylate-1.

That is, the present invention focuses on the fact that brominated compounds have a high refractive index, and uses the following structure in which the hydrogen of the alkyl group in the side chain of an alkyl methacrylate represented by the following structural formula (1), such as methyl methacrylide donor, is replaced with bromine. This is based on the fact that a plastic lens that satisfies the above requirements can be obtained by polymerizing bromoalkyl methacrylate represented by formula (11).

CH2-C(CH3)C00CnHk (I) However, n=an integer of 1 to 3, k=2n+1 or 2n.

CH2-C(CHCH2-C(CH3)C00CnHk
- However, n = integer from 1 to 3, k = 2 n +
The polybromoalkyl methacrylate obtained by polymerizing this bromoalkyl methacrylate has almost the same structure as the alkyl methacrylate (of the above formula (1)) before bromine substitution. The mechanical properties, transparency, etc. are the same.The greater the number of substituted bromine atoms, the more
The refractive index increases by -F.

Note that as the number of n increases, the glass transition point decreases,
If it is 124 or more, it becomes impractical as a plastic lens.

As a polymerization initiator for polymerizing bromoalkyl methacrylate, a conventional thermal polymerization catalyst can be used. Examples include organic peroxides such as t-butyl peroxybenzoate/benzoyl peroxide, t-butyl cumyl peroxide, and t-butyl peroxide. Furthermore, when producing a thin lens, it is also possible to carry out photopolymerization using a photopolymerization initiator in order to shorten the polymerization time. Examples of the photopolymerization initiator include acetophenone, benzophenone and derivatives thereof, and benzoin alkyl ether.

When using these photopolymerization initiators, it is not only possible to use them alone, but also to use them together with a thermal polymerization catalyst to effectively utilize the heat generated from the lamp during ultraviolet irradiation. It is.

In order to facilitate mold release, it is also possible to apply a known mold release agent to the surface of the mold in advance, or to add an internal mold release agent to the resin.

Examples of the present invention will be described below.

(Example) A concave glass mold with a diameter of 15 o'mm and a spherical radius of 2 oomn and a flat glass mold were prepared, and a gasket was inserted between the two glass molds so that the edge thickness was 3f+1 m. On the other hand, 2 parts by weight of benzoyl peroxide as a polymerization initiator was mixed and dissolved in bromoalkyl methacrylate to form a transparent solution. Pour this liquid between the glass molds,
Thermal polymerization was carried out at 60°C for 3 hours and then at 90°C for 2 hours. The refractive index of the resulting plano-convex plastic lens was measured. The results are shown in Liao 1 to 7 in the following table.

As a comparative example, next to alkyl methacrylate,
Plastic lenses were obtained in the same manner and their refractive indexes were measured, and the results are also shown for Rattans 8 to 10 in the following table.

By polymerizing with a Chrissie 14 polymerization initiator,
It can be seen that a plastic lens with a high refractive index can be obtained.

As explained above, according to the present invention, it is possible to provide a plastic lens with a higher refractive index than conventional ones, so it is possible to eliminate various aberrations by combining lenses with different refractive indexes and dispersion. This is something that can be expected to have many effects.

Name of agent: Patent attorney Toshio Nakao and 1 other person 11

Claims (1)

[Scope of Claims] A plastic lens characterized by using a resin obtained by polymerizing bromoalkyl methacrylate represented by the following structural formula. CH2=C(CH3)C00CnHk, mBrm, where n = integer from 1 to 3, k = 2 n +1 or -2n