JPH0311289B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a transparent resin having a high refractive index, and is characterized by irradiating light during the polymerization process. Conventionally, various studies have been conducted and proposals have been made regarding synthetic resins to replace inorganic glass. For example, transparent plastics such as polymethyl methacrylate, urea resin, and polystyrene are known. However, these had drawbacks such as low surface hardness, being easily scratched, and poor impact resistance and being easily torn. In order to further improve these drawbacks, transparent plastics having a crosslinked structure are produced by using diethylene glycol bisallyl carbonate or copolymers of such crosslinking monomers and other conventionally known monofunctional or polyfunctional monomers. has also been proposed. The characteristics of these transparent plastics include that they are lighter than inorganic glass, and that they do not easily injure the human body when broken, and are often used in close proximity to the human body, especially as optical lenses such as eyeglass lenses. The above-mentioned diethylene glycol bisallyl carbonate eyeglass lenses are currently being widely used for school children. However, in addition to the above-mentioned drawbacks such as low hardness and poor impact resistance, the transparent plastic has a low refractive index, which is a significant disadvantage for applications such as lenses. It becomes a drawback. Therefore, high refractive index polymers having a certain degree of hardness and impact resistance have also been proposed. For example, JP-A-55-13747 discloses the copolymerization of a dimethacrylate or diacrylate compound of a bisphenol A derivative with a monomer (hereinafter referred to as a high refractive index monomer) whose polymer itself gives a high refractive index. It has been proposed to obtain a resin with a high refractive index. Furthermore, it is also known that a resin with a high refractive index and flame retardancy can be obtained by copolymerizing a dimethacrylate or diacrylate compound having a nuclear halogen-substituted aromatic ring and a radically polymerizable monofunctional monomer having an aromatic ring. It is being (Tokukai Akira
55-69543) These organic glass plastics exhibit physical properties suitable for use as optical glasses, but since they are generally highly crosslinked resins, their manufacturing method (polymerization method) is difficult. For example, when manufacturing lenses, etc., a mold polymerization method is used in which a mixture of the monomer, peroxide as a polymerization initiator, and other chemicals as necessary is injected into a mold and polymerized by heating, but uniform polymerization control is not possible. It was difficult, and the yield was usually around 70-80%. In general, monomers for organic and optical glasses are expensive, and it is important to improve this yield, and by extension,
Obtaining homogeneous molded polymers has been a challenge for some time. The inventors of the present invention have conducted extensive research into ways to solve this problem, and have discovered a molding polymerization method in which the reduction in yield due to polymerization particles is substantially zero. That is, the present invention uses a dimethacrylate or diacrylate compound (A) having a halogen-substituted aromatic ring as a method for obtaining a uniform polymer that is transparent, has a high refractive index, and has high surface hardness and impact resistance. 1 to 90% by weight, and (A)
This is a method for producing a polymer, which comprises irradiating a mixture of 99 to 10% by weight of a compound (B) copolymerizable with light. A particularly preferred polymerization method of the present invention is to carry out the polymerization at or near room temperature, and to continue uniform light irradiation until the polymerization is sufficiently completed. Compared to the polymerization method of the present invention, conventional polymerization methods are carried out by adding an organic peroxide to monomers and heating them. In this case, the maximum number of polymerization initiating radicals is limited by the organic peroxide concentration;
There is always a temperature rise due to heat generation during polymerization, and once the reaction occurs, it is difficult to freely control the reaction rate, which tends to cause polymerization spots. In contrast, in the present invention, which uses light in the polymerization process, the reaction can be freely controlled by controlling the conditions of light irradiation, and the polymerization process can be made into two stages, the use of organic peroxides can be reduced, or It has the advantage that it can be polymerized without using it. In the present invention, even if an organic peroxide is present in the monomer system, a sensitizer is present, or a reagent that helps initiate these polymerizations is not present at all. Also, initiation of polymerization is performed by irradiation with light. Therefore, heating means is not substantially required. Therefore, the accumulation of internal strain due to the difference in thermal expansion between the monomer mixture and the molded polymer is avoided, resulting in a polymer with excellent impact resistance and no refractive index spots due to internal strain. Furthermore, since the light irradiation is naturally carried out from the surface, polymerization near the surface is achieved sufficiently uniformly, so that the expected surface hardness is also guaranteed. Dimethacrylate or diacrylate compound (A) having a halogen-substituted aromatic ring used in the present invention
is the general formula, [However, in the formula, R ¹ is hydrogen or a methyl group; R ² is an unsubstituted alkylene group having 2 to 3 carbon atoms; X is a halogen atom; m and n are integers whose total is 0 to 6;
k and l represent integers of 1 to 4. ] It is a compound represented by Halogen is not particularly limited and can be used, but bromine is preferred. The number of halogens is 1 to 4 per aromatic nucleus. R ₂ is an alkylene group having 2 to 3 carbon atoms that is not substituted with a functional group. Specifically, 2,2-bis(4-methacryloyloxyethoxy-3,5-dichlorophenyl)propane, 2,2-bis(4-methacryloyloxyethoxy-3,5-dipromphenyl)propane, 2,2-bis( 4-methacryloyloxypropoxy-3,5-diiodophenyl)propane, 2,2-bis(4-methacryloyloxyisopropoxy-2,3,5,6-latrachlorphenyl)propane, 2,2bis(4-
Methacryloyloxyethoxy-2,3,5,6
-tetrapromphenyl)propane, and mixtures thereof. Furthermore, the copolymerizable monomer used in the present invention is not limited and any known one can be used; however, if a homopolymer of the monomer has a high refractive index of 1.55 or higher, for example, the polymer of the present invention will also have a higher refractive index. This is desirable because it becomes the refractive index. Typical monomers that are generally preferably used include vinyl aromatic compounds such as styrene, vinyl ketone, and methoxystyrene; styrenes substituted with nuclear halogens such as chlorostyrene, bromustyrene, iodostyrene, dipromstyrene, and tribrostyrene; Acrylates and methacrylates such as phenyl methacrylate, chlorphenyl methacrylate, methoxyphenyl acrylate, diprombenzyl methacrylate, tripromphenyl methacrylate, benzyl acrylate, chlorobenzyl acrylate,
These include naphthalene derivatives such as vinylnaphthalene and β-naphthyl methacrylate, and mixtures thereof. Among these, in the present invention, it is desirable to use aromatic monomers substituted with nuclear halogen, especially when obtaining a plastic with a high refractive index. Therefore, in the present invention, in order to obtain a resin having a particularly high refractive index, dimethacrylate or diacrylate having a nuclear promone-substituted aromatic ring and a copolymerizable monomer having a nuclear halogen-substituted aromatic ring are used in combination. is desirable. In the present invention, dimethacrylate or diacrylate (A) having a nuclear halogen-substituted aromatic ring;
The mixing ratio of copolymerizable monomer (B) with (A) is generally 1 to 90% of the total, preferably 5 to 80% by weight.
For example, when selecting a halogen-free monomer such as styrene or vinylnaphthalene as (B), increase the amount of (A) or increase the number of halogens in the nuclear halogen substitution. It is preferable to use a compound having a large number of halogens, for example, a compound having 2 to 4 halogens per nucleus, and as (B), chlorstyrene,
When selecting a halogen-containing monomer such as promustyrene, the amount of (A) and the number of halogens in the nuclear halogen-substituted aromatic ring may be relatively small. Therefore, the composition ratio of the two components in the present invention is preferably determined in advance depending on the required physical properties such as mechanical properties and refractive index. The range that can be safely used is (A)
is about 30-70%. Next, in the method for producing a high refractive index transparent resin of the present invention, the most characteristic light irradiation means is a low-pressure mercury lamp, high-pressure mercury lamp, germicidal lamp, sunlight, etc. as the light source, and the curing time is Depending on the shape and intensity of the light source, you can choose between 10 seconds and several hours. Generally, it would be difficult to irradiate for a somewhat longer period of time. It may also be effective to add a photopolymerization initiator or photosensitizer to the monomer mixture prior to light irradiation. Examples of the photopolymerization initiator and photosensitizer include ordinary photopolymerization initiators and photosensitizers. Specific examples of such photopolymerization initiators and photosensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, acetoin, butyroin, toluoin, benzophenone, p-chlorobenzophenone, p- , melexybenzophenone, and the like. In the present invention, a known polymerization method can be used to polymerize the (meth)acrylate compound of the aromatic compound having a nuclear halogen and the copolymerizable monomer. A typical polymerization method is a cast polymerization method. For example, the mixture of copolymer monomers is injected into a transparent mold held by an elastomer gastight or a spacer, cured by irradiation with light, and then taken out. Of course, during the copolymerization, additives such as a mold release agent, an antioxidant, an anti-coloring agent, an antistatic agent, a fluorescent dye, and various stabilizers may be added as necessary in addition to the quantitative ratio of the monomers. It can be selected and used. Similarly, by mixing and using monomers having hydrophilic groups such as hydroxyl groups, epoxy groups, or carboxylic acid groups as part of the copolymerizable monomers, it is possible to improve dyeability and further improve surface properties. You can also do it. In addition, radical generators such as peroxides are added in an amount less than the amount normally used, e.g.
% or less is also effective for improving the polymerization rate. Examples of organic peroxides used for this purpose include diacyl peroxides such as acetyl peroxide, propionyl peroxide, launoyl peroxide, benzoyl peroxide, and decanoyl peroxide, diisopropyl peroxydicarbonate,
Peroxy dicarbonates such as di-2-ethoxyethyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-n-propyl peroxydicarbonate, myristyryl peroxydicarbonate, tert-butyl peroxyneodecanate, tertiary butyl peroxydicarbonate Examples include alkyl peresters such as le-butyl peroxy-2-ethylhexanate and tertiary-butyl peroxy bivalate. In order to explain the present invention more specifically, Examples are shown below. From these results, it can be easily understood that the manufacturing method of the present invention is superior. The present invention is not limited to these examples. Examples 1 to 3 Various monomers were thoroughly mixed with the composition shown in Table 1, and the mixed liquid was poured into a mold consisting of a transparent glass plate with a diameter of 73 mm and a gasket made of ethylene-vinyl acetate copolymer. and cast polymerization was carried out. Polymerization was carried out in an air oven at 30℃ using a sterilizing lamp (Toshiba sterilizing lamp).
GL15) was used for 12 hours of light irradiation from a distance of 3 cm. Various physical properties of the polymer thus obtained were measured and listed in Table 1. Comparative Example 1 Monomers with a composition of 60% by weight of 2,2-bis(4-methacryloyloxyethoxy-3,5-dipromphenyl)propane and 40% by weight of styrene were added with 1.0% by weight of diisopropyl peroxydi Add carbonate and mix well. This mixed solution was poured into a mold similar to that used in Examples 1 to 3, and cast polymerization was performed. Polymerization was initially started at 30°C using an air oven, and the temperature was gradually increased to 80°C after 18 hours. After further polymerization at 80°C for 2 hours, the polymer was taken out from the gasket and mold. The polymer is further
Post-polymerization was carried out at 100°C for 2 hours. Various physical properties of the polymer thus obtained were measured and listed in Table 1.

[Table] Examples 4 to 8 Each monomer mixture shown in Table 2 was used in Examples 1 to 3.
Polymerization by light irradiation is carried out in exactly the same manner as described above. The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1. General formula [However, in the formula, R ¹ is hydrogen or a methyl group; R ² is an unsubstituted alkylene group having 2 to 3 carbon atoms; X is a halogen atom; m and n are integers whose total is 0 to 6;
k and l represent integers of 1 to 4. ] Dimethacrylate or diacrylate compound (A) having a nuclear halogen-substituted aromatic ring represented by 1 to 90% by weight, and a polymerizable compound copolymerizable with (A)
A method for producing a copolymer, which comprises irradiating a mixture of (B) with 99 to 10% by weight of light.