JPS6322561B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a plastic lens, and more particularly to a plastic lens made of a copolymer of a 3,4,5,6-tetrabromophthalic acid allyl ester compound. Conventionally, plastic lenses have been widely used in optical products due to their ease of molding and light weight. Such plastic lens materials include:
Polymethyl methacrylate, polycarbonate, diethylene glycol bisallyl carbonate (CR-39), etc. are commonly used. However, compared to glass, polymethyl methacrylate and polycarbonate (refractive index n _D = 1.58) are both linear polymers and thermoplastics, so they are superior for mass production. It has poor workability in cutting, molding, etc., and it has been difficult to apply it to products with a wide variety of different shapes. CR-39 also has a refractive index of 1.45 to 1.50, which is lower than glass, so when used as a lens, the center thickness
The drawback was that the edge thickness tended to increase. Therefore, the present invention was made in view of the current situation, and intensive studies were carried out to obtain a polymer suitable for various optical elements, especially high refractive index plastic lenses. Focusing on diallyl phthalate resin (refractive index n _D = 1.57), the inventors discovered that a tetrabromophthalic acid allyl ester derivative in which the benzene ring is substituted with bromine has a high refractive index and is suitable as a plastic lens. That is, the plastic lens of the present invention comprises a 3,4,5,6-tetrabromophthalic acid allyl ester compound represented by the following structural formula (1) and a benzoic acid unsaturated ester represented by the following structural formula (2) or the following structure. formula
It is made of a copolymer of (3) with unsaturated phthalic acid ester, and is transparent and has a refractive index of 1.58 to 1.63. Here, in formula (1), R ₁ and R ₂ are a hydrogen atom, a methyl group or a chlorine atom. However, this excludes the case where R ₁ and R ₂ are both hydrogen atoms. Furthermore, in formulas (2) and (3), R ₃ and R ₄ are a hydrogen atom or a methyl group. Specific examples of the tetrabromophthalic acid allyl ester compounds used in the present invention include the following. 3,4,5,6-tetrabromophthalic acid bis(2
-methyl-2-propenyl) Allyl 3,4,5,6-tetrabromophthalate,
2-methyl-2-propenyl 3,4,5,6-tetrabromophthalic acid bis(2
-chloro-2-propenyl) 2-chloro-2-propenyl, 2'-methyl-2'-propenyl 3,4,5,6-tetrabromophthalate Allyl 3,4,5,6-tetrabromophthalate,
2-Chlor-2-propenyl The 3,4,5,6-tetrabromophthalic acid allyl ester compound used in the present invention can be produced by the following method or method. Method Method For example, the method involves reacting 3,4,5,6-tetrabromophthalic anhydride A with methallyl alcohol (B, R ₁ =CH ₃ ) to form 3,4,5,6
-Produce 2-methyl-2-propenyl tetrabromophthalate half ester (C, R ₁ = CH ₃ ), and react with KOH to produce 3,4,5,6-
2-Methyl-2-propenyl, potassium tetrabromophthalate (D, R ₁ = CH ₃ ) is prepared, and the resulting D is treated with methallyl chloride (E, R ₂ ) in a polar aprotic solvent such as dimethyl sulfoxide.
= CH ₃ , X = Cl), 3, 4, 5,
Bis(2-methyl-2-6-tetrabromophthalate)
-propenyl) (F, R ₁ =R ₂ =CH ₃ ) is obtained. According to the method, compound F is obtained by reacting potassium 3,4,5,6-tetrabromophthalate G with, for example, methallyl chloride E. In addition, as is clear from the above methods and methods, in compound F, R ₁ and R ₂ are hydrogen atoms,
It is a methyl group or a chlorine atom, and R ₁ and R ₂ may be the same or different, except when R ₁ and R ₂ are both hydrogen atoms. The polymerization of such tetrabromophthalic acid allyl ester compound F is carried out using a conventional radical polymerization initiator, such as benzoyl peroxide, dichlorobenzoyl peroxide, t-butyl peroxide, etc., and other well-known allyl esters, such as It can be easily polymerized in substantially the same manner as diallyl phthalate. In addition, in the present invention, since Compound F is usually a crystalline substance, the polymerization rate and the polymerization process can be easily controlled.
In addition, in order to avoid adverse effects on the mechanical and optical properties of the polymer as much as possible, a liquid copolymerizing agent is used to form a copolymer. Copolymerization agents used for this purpose include:
For example, benzoic acid unsaturated ester H or phthalic acid unsaturated ester I shown by the following general formula is used.

【formula】

[Formula] Specifically, allyl benzoate (H, R ₃ = H), methallyl benzoate (H, R ₃ = CH ₃ ), diallyl phthalate (I, R ₃ = R ₄ = H), bis phthalate (2-methyl-2-propenyl) (I, R ₃ =R ₄ =CH ₃ ), and the like. These copolymerization agents are liquid at room temperature, can serve as a solvent for the allyl tetrabromophthalate compound and polymerization initiator, are copolymerizable with the allyl tetrabromophthalate compound, and have high polymerizability. It is selected because it has the same degree of refractive index as that of the tetrabromophthalic acid allyl ester compound used, the degree of decrease in the refractive index of the copolymer due to the use of the copolymerization agent is small, and the transparency is not impaired. However, it is not limited to the above compounds H and I as long as these conditions are satisfied. Although the content of the allyl tetrabromophthalate compound in the allyl tetrabromophthalate ester copolymer varies depending on the substituents of the allyl tetrabromophthalate compound (R ₁ and R ₂ in F above), It is usually 20 to 90% by weight, preferably 50 to 80% by weight. If the content of the tetrabromophthalic acid allyl ester compound is less than 20% by weight, the effect of increasing the refractive index will be small and it will not be practical for producing high refractive index plastic lenses. Even if the content of the tetrabromophthalic acid allyl ester compound is 50% by weight or more, the closer it is to 50% by weight, the more
Naturally, the refractive index of the resulting copolymer decreases accordingly, but the liquid temperature range of the monomer mixture widens, and the control of the polymerization reaction becomes easier. Note that when the content of the tetrabromophthalic acid allyl ester compound exceeds 80%, the homogeneous liquefaction temperature of the monomer mixture increases and may exceed 70°C depending on the type of substituent, so the polymerization reaction is carried out at 80°C.
It becomes necessary to start from a heated state to a certain extent, and the copolymer tends to be colored. Specifically, it is performed as follows. That is, a tetrabromophthalic acid allyl ester compound and a radical initiator are separately dissolved in a copolymerization agent as a solvent, and then co-polymerized with a tetrabromophthalic acid allyl ester compound that has been preheated to a polymerization temperature of usually 60 to 70°C. A catalyst solution is added to the mixture with the polymerization agent, mixed and homogenized to initiate polymerization. Generally, the temperature is increased from 60 to 70℃ to 70 to 80℃ in stages.
The temperature is raised to 80-100°C to allow polymerization to proceed. Note that excessively rapid polymerization leaves distortions in the product due to polymerization shrinkage, etc., and must be avoided. The higher the temperature, the more complete the polymerization will be, but excessive temperature rise is undesirable as it may cause discoloration. Generally, it is appropriate to set the upper limit to 100 to 120°C. Furthermore, depending on the degree of progress of polymerization, crystals may be difficult to precipitate even after cooling, so polymerization can be carried out at a lower temperature if necessary. Alternatively, if the product is sealed and polymerized in a polymerization container having a previously polished glass surface or the like on the inner wall, a polymer product having a desired shape and having a surface corresponding to the polished surface can be directly obtained. The obtained polymer has structural units of the following formulas (4) and (5) or (4) and (6), is transparent, has a refractive index of 1.58 to 1.63, and is a three-dimensional copolymer. Since it is a crosslinked product, it is insoluble in solvents and can be easily subjected to mechanical processing such as cutting and polishing. The relationship between the composition and refractive index of the optical plastic lens obtained according to the present invention is illustrated in the table below. As is clear from this table, each material has a high refractive index and is suitable for lenses such as optical lenses and eyeglass lenses, and the material itself can also be used for optical elements such as prisms.

【table】

[Table] Examples of the present invention are shown below. Example 1 3,4,5,6-tetrabromophthalic acid allyl ester F was produced according to the above production method as shown in the reaction formula below. That is, 20 g (43.1 mmol) of 3,4,5,6-tetrabromophthalic anhydride A was added to 90 ml of methallyl alcohol B, and heated to 80 DEG C. with stirring to gradually dissolve it. After dissolution, the mixture was kept at 80° C. for another 2 hours, then 3.0 g (45.9 mmol) of KOH was added to neutralize it, and the mixture was cooled. The precipitated white crystals were separated, washed with a small amount of ethanol, and then dried to obtain 17.9 g of potassium 3,4,5,6-tetrabromophthalate, 2-methyl-2-propenyl D. The yield was 74%, and the melting point was 250°C or higher. When 17.9 g of this compound D and 3.4 g of methallyl chloride E were stirred in 200 ml of dimethyl sulfoxide at 60°C for 2 hours, compound D was dissolved to obtain a yellow transparent liquid. To this clear liquid was added 1 IN aqueous hydrochloric acid solution, and then extracted 42 times with 350 ml of ether. The ether extracts were combined and the ether was then distilled off. The residue was recrystallized from hexane to give 3, 4, 5,
Bis(2-methyl-2-6-tetrabromophthalate)
-propenyl) F11.2g was obtained. The yield was 61%, colorless needle crystals with a melting point of 85-86°C. Example 2 20 g (35.8 mmol) of dipotassium 3,4,5,6-tetrabromophthalate G, 2,3-dichloropropene (in E,
10 g (90.1 mmol) of R ₂ =X=Cl) was reacted in 200 ml of dimethyl sulfoxide by stirring at 60° C. for one day to obtain a homogeneous solution. This solution was diluted with 1 part of IN aqueous hydrochloric acid solution and extracted several times with ether. The combined ether solution was washed with water, dried, and then the ether was distilled off. When the residue was recrystallized from cyclohexane,
3,4,5,6-tetrabromophthalic acid bis(2
13.6 g of (chloro-2-propenyl) F was obtained.
The yield was 60%, and the melting point was 109-110°C. Example 3 100 parts of bis(2-methyl-2-propenyl) 3,4,5,6-tetrabromophthalate, 46 parts of 2-methyl-2-propenyl benzoate, and 5 parts of benzoyl peroxide were mixed; 80 in the water bath
After heating to ℃ and shaking to make it homogeneous,
Transfer this liquid into glass molds 2 and 2' fixed with gaskets 1 as shown in the figure, press them with pressure springs 3,
The temperature was lowered to 60°C over 1 hour, and the mixture was left in this state for 15 hours. Furthermore, at 70℃ for 2 hours, at 80℃ for 4 hours, and at 100℃ for 5 hours.
When heated for a period of time, a transparent and hard plastic lens was obtained. This lens had excellent plastic properties and a refractive index of 1.618. Example 4 88 parts of bis(2-methyl-2-propenyl) 3,4,5,6-tetrabromophthalate, 10 parts of 2-methyl-2-propenyl benzoate, and 2 parts of benzoyl peroxide as in Example 3. A transparent plastic lens with a refractive index of 1.628 was obtained by polymerization. Example 5 Bis(2-chloro-2-propenyl) 3,4,5,6-tetrabromophthalate was polymerized in the same manner as in Example 3 using diallyl phthalate as a copolymerization agent and benzoyl peroxide as a catalyst. A transparent, hard, high refractive index plastic lens was obtained. The relationship between weight ratio and refractive index is shown in the table above. Example 6 2-chloro-2-propenyl 3,4,5,6-tetrabromophthalate, 100 parts of 2'-methyl-2'-propenyl, 143 parts of diallylphthalate, and 9 parts of benzoyl peroxide were mixed in a water bath at 80°C. It was heated for 20 minutes to uniformly dissolve it. This was heated at 60°C as in Example 3.
Transfer to a polymerization container like the one shown, which has been heated to
A transparent plastic lens with a refractive index of 1.589 was heated at 60°C for 20 hours, 70°C for 3 hours, and 80°C for 1 hour.4
I got it.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing an example of a gasket used in manufacturing the plastic lens of the present invention. 1...Soft resin gasket, 2...Glass type,
3... Pressure spring, 4... Molded lens.

Claims (1)

[Scope of Claims] 1 A 3,4,5,6-tetrabromophthalic acid allyl ester compound represented by the following structural formula (1) and a benzoic acid unsaturated ester represented by the following structural formula (2) or the following structural formula ( A transparent plastic lens made of a copolymer of 3) with an unsaturated phthalic ester and having a refractive index of 1.58 to 1.63. Here, in formula (1), R ₁ and R ₂ are a hydrogen atom, a methyl group or a chlorine atom. However, this excludes the case where R ₁ and R ₂ are both hydrogen atoms. Furthermore, in formulas (2) and (3), R ₃ and R ₄ are a hydrogen atom or a methyl group.