JPH0128054B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to high refractive index resins, and particularly provides a method for producing high refractive index resins having excellent polymerization moldability. Conventionally, various synthetic resins have been researched and proposed to replace inorganic glass, but the refractive index of synthetic resins such as diethylene glycol bisallyl carbonate polymers is as low as 1.49 compared to inorganic glasses. In recent years, attempts have been made to further improve the refractive index of synthetic resins and apply them to optical lenses, for example, in Japanese Patent Application Laid-Open No. 13747-1983.
This was done in Japanese Patent Publication No. 54-77686. However, most of the monomers used as raw materials for the synthetic resins are vinyl compounds, acrylates, or methacrylates. On the other hand, the polymer of diethylene glycol bisallyl carbonate has a low refractive index of 1.49, but since the monomer is an allyl compound, the polymerization rate is slow, so the polymerization proceeds slowly and the surface condition of the cast polymer is excellent. It has very good polymerization properties. On the other hand, in the case of the above-mentioned high refractive index resin, the refractive index is improved to 1.57 to 1.61, but the polymerization rate is low because the raw material monomer is a vinyl compound, dimethacrylate, diacrylate, methacrylate, or acrylate. Therefore, the surface condition of the cast polymer is poor and the polymerization moldability is poor. In the case of a cast polymer having such a crosslinked structure, the poor surface condition of the polymer is a fatal drawback for optical elements such as lenses, and it not only has no commercial value, but also has no commercial value.
Product productivity also decreases. As a result of many years of intensive research into a method for producing a high refractive index resin that compensates for the above-mentioned drawbacks, the present inventors have discovered that a specific monomer represented by the following general formula (1) has excellent polymerization moldability. The present inventors have discovered that the present invention is extremely useful as a raw material for high refractive index resins, and have completed the present invention. That is, the present invention comprises 5 to 90% by weight of one or more first monomers represented by the general formula (); (In the formula, R represents hydrogen, chlorine, bromine, or a methoxy group, and a represents 1 or 2) A homopolymer having a refractive index of 1.56 or more, having an aromatic ring, and capable of monofunctional radical polymerization. The present invention provides a method for producing a high refractive index resin, which comprises copolymerizing 95 to 10% by weight of at least one type of second monomer in the presence of a radical polymerization initiator. According to the present invention, it is possible to obtain a resin that not only has a high refractive index of 1.58, but also has excellent transparency as a cast polymer, and has an excellent surface condition. The present invention will be explained in detail below. As the first monomer represented by the general formula () used in the present invention, known ones can be used, and representative examples that can be suitably used are as follows. For example, allyl cinnamate, allyl ortho-chlorocinnamate, allyl meta-chlorocinnamate, allyl para-chlorocinnamate, allyl bromocinnamate, allyl iodocinnamate, allyl dichlorocinnamate, allyl dibromocinnamate, (omp) Allyl methoxycinnamate and mixtures thereof. Furthermore, the refractive index of the homopolymer used in the present invention is
The monofunctional radically polymerizable second monomer having an aromatic ring of 1.56 or more is not particularly limited, and known ones can be used, but representative examples that can be suitably used are as follows. It is. For example, styrene derivatives such as chlorstyrene, bromstyrene, iodostyrene, dichlorostyrene, dibromstyrene, trichlorostyrene, tetrachlorostyrene, styrene, vinyltoluene, methoxystyrene; phenyl methacrylate, phenyl acrylate, chlorphenyl Methacrylate, dichlorophenyl methacrylate, bromphenyl methacrylate, dibromphenyl acrylate, methoxyphenyl methacrylate, benzyl acrylate, benzyl methacrylate, chlorobenzyl methacrylate, chlorobenzyl acrylate, bromobenzyl methacrylate, bromobenzyl acrylate, dibromobenzyl methacrylate, Dichlorobenzyl methacrylate, dibromobenzyl acrylate, tribromobenzyl methacrylate, pentabromo phenyl methacrylate, tribromo phenyl methacrylate, pentachloro phenyl methacrylate, trichloro phenyl methacrylate, pentabro phenyl acrylate, trichloro phenyl acrylate, etc. Acrylates and methacrylates; Others include naphthalene derivatives such as 1-vinylnaphthalene, 2-vinylnaphthalene, α-naphthyl methacrylate, β-naphthyl methacrylate, α-naphthyl acrylate, β-naphthyl acrylate, and mixtures thereof. Applications of high refractive index resins in place of inorganic glass include not only optical lenses but also prisms, dustproof glass, windshield glasses, etc., and the physical properties required differ depending on each field. Therefore, the types of the first monomer and the second monomer and the composition ratio of both components are preferably determined in advance depending on the required mechanical properties, refractive index, etc. The amount of the first monomer to be used relative to the second monomer cannot be absolutely limited, but it is 5 to 90% by weight.
Most commonly, it is preferably used in a range of 10 to 80% by weight. However, if the amount of the second monomer is less than 5% by weight, the polymerization moldability is not sufficiently improved. The resin of the present invention obtained from the first monomer and the second monomer is transparent and exhibits a high refractive index, but depending on the use of the resin, it is desired to further improve properties such as processability. In such cases, it is preferable to add a polyfunctional radically polymerizable third monomer. As the third monomer, known ones can be used, and examples of those that can be suitably used are as follows. For example, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, propylene glycol dimethacrylate, propylene glycol diacrylate, 1,4-butane diform dimethacrylate Dimethacrylates or diacrylates of aliphatic polyhydric alcohols, trimethylolpropane trimethacrylates; 2,2bis(4-methacryloxyphenyl)propane;
2,2bis(4-methacryloxydiethoxyphenyl)propane, 2,2bis(4-methacryloxydiethoxyphenyl)propane, 2,2bis(4-methacryloxydiethoxyphenyl)propane
-methacryloxy-3-chlorophenyl)propane, 2,2bis(4-acryloxy-3-chlorophenyl)propane, 2,2bis(4-methacryloxy-3,5-dichlorophenyl)propane,
2,2bis(4-methacryloxy-3-bromphenyl)propane, 2,2bis(4-methacryloxy-3,5-dibromphenyl)propane,
2,2-bis(4-acryloxy-3,5-dibromphenyl)propane, 2,2bis(4-methacryloxyethoxy-3-chlorophenyl)propane, 2,2bis(4-methacryloxyethoxy-3-bromphenyl) Propane, 2,2bis(4-methacryloxyethoxy-3,5-dibromphenyl)propane, 2,2bis(4-methacryloxyethoxy-3,5-dichlorophenyl)
Propane, 2,2bis(4-acryloxyethoxy-3,5-dibromphenyl)propane, dimethacryloxydiphenylmethane, dimethacryloxydi(4-chlorophenyl)methane, 1,4-dimethacryloxybenzene, 1, 4-dimethacryloxyethoxybenzene, 1,4-dimethacryloxy-2,3,5,6-tetrabromobenzene,
1,4-dimethacryloxyethoxy-2,3,
5,6-tetrachlorobenzene, 1,4-dimethacryloxyethoxy-2,3,5,6-tetrabromobenzene, di(2-methacryloxyethyl) terephthalate, di(2-methacryloxyethyl) tetrabromterephthalate (methacryloxyethyl), di(2-methacryloxyethyl) tetrabromophthalate, 1,
These include 5-dimethacryloxinaphthalene, 2,2'-propane bis[3(4-phenoxy)-1,2-hydroxypropane-1-methacrylate], and mixtures thereof. The amount of the third monomer to be used relative to the first monomer and the second monomer cannot be absolutely limited and is determined depending on the required physical properties, but if it is too large, the refractive index of the resulting resin will decrease. Therefore, it is most commonly used in a range of 1 to 50% by weight, preferably 5 to 45% by weight. In this case, the amount of the first monomer used is at least 10% by weight of the total monomers. The high refractive index resin in the present invention is obtained by polymerizing the above monomer in the presence of a radical polymerization initiator. The radical polymerization initiator is not particularly limited, and known ones can be used. That is, they are common radical polymerization initiators such as diisopropyl peroxydicarbonate, azobisisobutyronitrile, and benzoyl peracetate. The amount of the radical polymerization initiator to be used varies depending on the polymerization formation, polymerization conditions, type of monomer in the copolymerization component, etc., and cannot be absolutely limited, but in general, it is 0.01 to 10% by weight based on the total monomers. It is most preferable to use the range of %. The method of copolymerizing the first monomer, second monomer, and/or third monomer in the present invention is not particularly limited, and any known polymerization method can be employed. An example of a typical polymerization method is a cast polymerization method. For example, injecting the mixture of copolymerization component monomers containing a radical polymerization initiator between molds held by an elastomer gasket or a spacer,
It is best to cure it in an air oven and then take it out. It is also possible to preliminarily polymerize a mixture of copolymerization component monomers in the presence of a polymerization initiator to increase the viscosity of the mixture, and then perform cast polymerization. Among the polymerization conditions,
In particular, temperature affects the properties of the high refractive index resin obtained. In general, polymerization is started slowly at a relatively low temperature, and when the polymerization is completed, it is cured at a high temperature.
It is preferred to carry out a staged polymerization. For example, room temperature~
After polymerizing slowly at around 70℃, 80~120℃
It is preferable to terminate the polymerization at a relatively high temperature. In particular, when the objective is to obtain a thick high refractive index resin, it is preferable to lengthen the polymerization time at a low temperature or to perform the above-mentioned prepolymerization. however,
If the polymerization time is too long, particularly at a high temperature, the resin may become colored, for example, yellow or yellowish brown, so it is not preferable to select a polymerization time longer than necessary. Generally, it is preferable to select conditions such that copolymerization is completed in 2 to 40 hours. Since the polymerization time varies depending on various conditions, it is preferable to determine the optimum time according to these conditions in advance. Of course, during the copolymerization,
Additions of mold release agents, ultraviolet absorbers, antioxidants, color inhibitors, antistatic agents, fluorescent dyes, and various other stabilizers can be selected and used as necessary. In order to explain the present invention more specifically, Examples and corresponding comparative examples are shown below. From now on, in particular, the first compound represented by the general formula () of the present invention
It will be easily understood that by using the monomer, a highly transparent resin with a high refractive index can be obtained.
Of course, the present invention is not limited to these examples. The physical properties of the high refractive index resins obtained in Examples and Comparative Examples were measured by the following test methods. (1) Refractive index The refractive index at 20°C was measured using an Atsube refractometer. Monobromnaphthalene was used as a contact liquid. (2) Light transmittance Measured on a 2 mm thick test piece using a haze meter (Toyo Seiki Seisakusho). (3) Surface condition The surface (front and back) of the cast polymer was observed with the naked eye. Example 1 Chlorstyrene (ortho form 64
A mixture of 36% by weight of para-isomer) was added in the composition shown in Table 1, and 3.0 parts by weight of diisopropyl peroxydicarbonate as a radical polymerization initiator was added and mixed well. This mixed solution was poured into a mold consisting of a glass plate with a diameter of 73 mm and a gasket made of ethylene-vinyl acetate copolymer, and cast polymerization was performed. Polymerization was carried out using an air heating furnace, and the polymerization was initially carried out at 30°C for 10 hours, and then the temperature was gradually raised to 50°C over 10 hours. Thereafter, the temperature was raised to 70°C over 1 hour, and polymerization was further carried out at 70°C for 10 hours. After the polymerization was completed, the mold was taken out of the air oven, and after being left to cool, the polymer was peeled off from the glass of the mold. Various physical properties of the polymer were measured and shown in Table 1.

[Table] Comparative Example 1 In Example 1, allyl cinnamate was not used,
When only chlorostyrene is polymerized, when removing the cast polymer from the glass plate after polymerization,
The cast polymer is destroyed (the details are unknown, but
It is assumed that this is due to polymerization strain). Furthermore, the surface of the cast polymer was extremely uneven, making the molded product very impractical. Comparative Example 2 2,2-bis(4-methacryloxyethoxyphenyl)propane was used instead of allyl cinnamate in Example 1, and 30/70 (wt%) with chlorstyrene was used.
0.1 part by weight of an initiator diisopropyl peroxydicarbonate was added at the composition ratio, and cast polymerization was carried out in the same manner. The refractive index (n ²⁰ _D ) of the obtained resin was 1.594, but the surface condition was poor with unevenness observed on both the front and back surfaces. Comparative Example 3 After thoroughly mixing 50 parts by weight of methyl cinnamate, 50 parts by weight of chlorstyrene (a mixture of 64% by weight of ortho form and 36% by weight of para form), and 3.0 parts by weight of diisopropyl peroxydicarbonate as a radical initiator, Cast polymerization was carried out in the same manner as in Example 1. Even after the polymerization process, the contents inside the mold remain liquid.
It was found that no polymerization occurred. Example 2 In the same manner as in Example 1, the compositions of allyl cinnamate and chlorstyrene were changed as shown in Table 2, and 2 parts by weight of benzoyl peroxide was used as a polymerization initiator (however, No. 5 in Table 2 4 parts by weight) were added, and cast polymerization was carried out at a temperature of 80° C. for 14 hours using a nylon gasket. The results are shown in Table 2. In all cases, transparent resins with high refractive index and smooth surface condition of the cast polymer were obtained.

[Table] Example 3 All the same procedures as in Example 1 (No. 2 in Table 1) were repeated except that the monomer shown in Table 3 was used instead of allyl cinnamate in Example 1 (No. 2 in Table 1). It was carried out in the same manner as 2). The results are shown in Table 3. In both cases, resins were obtained that were transparent, had a high refractive index, and had good processability.

[Table] Example 4 In Example 1 (Table 1 No. 3), the monomers shown in Table 4 were used instead of chlorstyrene, and diisopropyl peroxydicarbonate was used as the radical polymerization initiator as shown in Table 4. Cast polymerization was carried out using the same amount. Polymerization was initially carried out at 30°C for 4 hours, and then the temperature was gradually raised to 50°C over 10 hours. Thereafter, the temperature was raised to 70°C over 1 hour, and polymerization was further carried out at 70°C for 4 hours. The rest was carried out in exactly the same manner as in Example 1 (Table 1 No. 3). The results are shown in Table 4.

[Table] Example 5 Allyl cinnamate, chlorstyrene, and the third monomer were used in the composition shown in Table 5, and 0.3 parts by weight of diisopropyl peroxydicarbonate was added as a radical polymerization initiator and mixed well. This mixed solution was poured into a mold made of a gasket made of ethylene-vinyl acetate copolymer and glass with a diameter of 73 mm, and cast polymerization was performed. Polymerization was initially carried out at 30°C.
After polymerization for 10 hours, the temperature was gradually raised to 50°C over 4 hours. Further, the polymerization was carried out at 70°C for 1 hour, and then at 100°C for 30 minutes. The results are shown in Table 5.

【table】

[Table] Example 6 As in Example 5, allyl cinnamate, chlorstyrene and the third monomer were used in the composition shown in Table 6,
0.5 parts by weight of diisopropyl peroxydicarbonate as a radical polymerization initiator was added and mixed well. Polymerization was first carried out at 30°C for 4 hours, then
The temperature was gradually raised to 50°C in 10 hours. 1 more
After raising the temperature to 70°C for an hour, polymerization was carried out at 70°C for 1 hour. The rest was carried out in exactly the same manner as in Example 5.
The results are shown in Table 6.

[Table] Bread

Claims (1)

[Claims] 1 [A] 5 to 90% by weight of one or more first monomers represented by general formula (1); (R in the formula represents hydrogen, chlorine, bromine, or methoxy group, and a represents 1 or 2) [B] Monofunctional radical polymerization in which the homopolymer has a refractive index of 1.56 or more and has an aromatic ring. possible 1
A method for producing a high refractive index resin, comprising copolymerizing 95 to 10% by weight of at least one second monomer in the presence of a radical polymerization initiator. 2. The method for producing a high refractive index resin according to claim 1, wherein the first monomer represented by general formula (1) is allyl cinnamate. 3. The method for producing a high refractive index resin according to claim 1, wherein the second monomer is chlorstyrene. 4 [A] 5 to 90% by weight of one or more first monomers represented by general formula (1) (based on the total amount of the first monomer and second monomer) and based on the total monomer 10% by weight or more, (R and a in the formula are the same as above) [B] A monofunctional radical polymerizable monopolymer having a refractive index of 1.56 or more and having an aromatic ring.
95 to 10% by weight (based on the total amount of the first monomer and second monomer) of at least one second monomer; and [C] a polyfunctional radically polymerizable third monomer. A method for producing a high refractive index resin, which comprises copolymerizing 1 to 50% by weight of the total monomers in the presence of a radical polymerization initiator.