JPS6325321B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a plastic lens, and more particularly to a plastic lens comprising a polymer of a tetrabromophthalic acid ester derivative. Conventionally, plastic lenses have been widely used in optical products due to their characteristics such as easy molding and light weight. Polymethyl methacrylate, polycarbonate, diethylene glycol bisallyl carbonate (CR-39), and the like are generally used as materials for such plastic lenses. However, compared to glass, these plastic lens materials, such as polymethyl methacrylate and polycarbonate (refractive index n _D = 1.58),
Since both are linear polymers and thermoplastic, they are excellent for mass production, but they have poor processability in cutting, molding, etc., making it difficult to apply them to a wide variety of designs. CR-39 also has a relatively low refractive index of 1.49 to 1.50, so when used as a lens, it has the disadvantage that the center thickness and edge thickness tend to be large. Therefore, the present invention was made in view of the current situation, and in order to obtain a polymer suitable for various optical elements, especially high refractive index plastic lenses, the present invention was made using diallyl, which has excellent heat resistance and dimensional stability. Focusing on phthalate resin (refractive index n _D = 1.57), we replaced the benzene ring with bromine, inserted an ethylene glycol chain to lower the melting point of the monomer, and then introduced a general-purpose polymerization functional group to create a high refractive index plastic. A monomer for lenses was synthesized. Although this product is easily polymerized using a common radical polymerization initiator, the present invention was completed based on the discovery that the three-dimensional polymer produced is suitable as a plastic lens. That is, the plastic lens of the present invention is a homopolymer of a tetrabromophthalate derivative represented by the following structural formula, or a tetrabromophthalate derivative selected from the group consisting of an allyl ester, an acrylate ester, and a methacrylate ester. It is transparent, has a refractive index of 1.56 to 1.58, and has a refractive index of 33 to 1.58.
It has an Atsube number of 35 and a pencil hardness of H to 3H. The above-mentioned tetrabromophthalic acid ester derivative used in the present invention can be produced by the following method. That is, commercially available 3,4,5,6-tetrabromophthalic anhydride (A) was reacted with an aqueous potassium hydroxide solution to produce dipotassium 6,4,5,6-tetrabromophthalate (B). , when ethylene chlorohydrin ((C), X=Cl) or ethylene bromohydrin ((C), X=Br) acts on this, 3,4,
Bis(2-hydroxyethyl) 5,6-tetrabromophthalate (D) is obtained. Then, by reacting (D) with allyl chloroformate (E), bis(2-allylcarbonatoethyl) 3,4,5,6-tetrabromophthalate (F) is obtained. Note that if a compound having a substituent on the allyl group or the like is used as allyl chloroformate (E), phthalate derivatives (F) having various substituents can be obtained. Although the phthalate derivative (F) has four bromine atoms, it is a colorless liquid, so it is convenient to pour into a mold or mix with a copolymerizing agent. The polymerization of compound (F) is carried out using conventional radical polymerization initiators such as benzoyl peroxide, dichlorobenzoyl peroxide, di-t-butyl peroxide, diisopropylpeneoxydicarbonate, and other well-known radical polymerization initiators. It can be polymerized in almost the same manner as allyl esters such as diallyl phthalate and styrene. In the present invention, the homopolymer of the phthalate ester derivative (F) can be used as a plastic lens, but allyl esters such as diallyl phthalate, diallyl isophthalate, and esters of acrylic acid and methacrylic acid, such as A copolymer with at least one copolymerizer selected from the group consisting of benzyl methacrylate, phenyl methacrylate and benzyl acrylate can also be used as a plastic lens. These copolymerization agents must be able to mix uniformly and be copolymerized with compound (F), and furthermore, their polymerizability must be on the same level as that of compound (F), and the refraction of the copolymer due to the use of the copolymerization agent It is selected because the degree of decrease in the ratio is small and the transparency is not impaired. The content of compound (F) in the copolymer depends on the type of copolymerizing agent, but is usually 20 to 100% by weight.
Preferably it is 50 to 100% by weight. If the content of compound (F) is less than 20% by weight, the effect of increasing the refractive index will be small, making it impractical to obtain a high refractive index material. Polymerization is carried out using a compound (F) to which a radical polymerization initiator has been added.
A polymerization solution prepared by adding a radical polymerization agent to a mixture of a copolymerization agent and compound (F) is poured into a glass polymerization container (glass type) and heated at 30 to 40℃.
This is done by gradually increasing the temperature. Incidentally, if the temperature is raised too quickly for polymerization, distortions due to polymerization, condensation, etc. may remain in the product, or popcorn polymerization may occur, so it must be avoided. The temperature increase limit is usually around 100℃. Furthermore, if the glass mold used has a previously polished surface and inner wall, a polymer product with a desired shape and a surface corresponding to the polished surface can be obtained. All of the obtained polymers are colorless and transparent, have a structural unit of the following formula (), are insoluble in solvents, Since it is a three-dimensional crosslinked body, mechanical processing such as cutting and polishing is easy. The resin composition, refractive index, Abbe's number, and pencil hardness of the plastic lens obtained according to the present invention are illustrated in the table below. As is clear from this table, the plastic lens of the present invention 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. be.

【table】

[Table] Examples of the present invention will be described below. Example 1 Commercially available 3,4,5,6-tetrabromophthalic anhydride (A) was treated with an aqueous potassium hydroxide solution (7% by weight) to produce potassium 3,4,5,6-tetrabromophthalate. I got (B). The yield was 4%, and the melting point was 250°C or higher. 48 g (86.0 mmol) of this compound (B) and 28 g (224 mmol) of ethylene bromohydrin ((C),
When the mixture was stirred for a day and night, compound (B) was dissolved to obtain a pale yellow transparent liquid. Dimethyl sulfoxide was distilled off from this liquid under reduced pressure to concentrate it to about double the concentration, to which was added 1N aqueous hydrochloric acid solution, and then extracted twice with 350 ml of ether. The residue was recrystallized from ethyl acetate to give 3,4,
32 g of bis(2-hydroxyethyl) 5,6-tetrabromophthalate (D) was obtained. Yield 64%, melting point 137
It was a colorless powder at ~139°C. 8.6 g (17 mmol) of this compound (D) and pyridine
4.5 g (57 mmol) was placed in 70 ml of dry benzene, and while cooling this with ice water to below 50°C,
30 ml of allyl chloroformate (E) 6.2 g (52 mmol)
A solution dissolved in dry benzene was added dropwise over about 30 minutes. After dropping, stir overnight at room temperature and add benzene 100
ml, add 100 ml of 1N hydrochloric acid aqueous solution to
Washed twice. Thereafter, it was washed twice with 100 ml of 0.5N aqueous potassium hydroxide solution and then twice with 100 ml of water. After distilling off the solvent from this benzene solution, preparative purification was performed using silica gel chromatography to obtain 8.9 g (13 mmol) of bis(2-allylcarbonatoethyl 3,4,5,6-tetrabromophthalate). I got (F). The yield was 76%, and the product was a colorless and transparent liquid. Compound (F) was identified by the following infrared absorption spectrum and nuclear magnetic resonance spectrum. Infrared absorption spectrum (cm ^-1 ): 1757, 1470, 1210,
1155, 1075, 1030, 945 Nuclear magnetic resonance spectrum ( ^13C -NMR (δppm)) a164.2, b154.6, c134.7, d132.6, e131.4,
f122.9, g119.1, h68.7, i64.9, j64.2 Example 2 5 parts of diisopropyl peroxydicarbonate as a polymerization initiator was added to 10 parts of the compound (F) obtained in Example 1, and the mixture was uniformly mixed. After curing, the gasket 1 having glass molds 2 and 2' as shown in the figure was filled, and polymerization was carried out by gradually raising the temperature from 40° C. while holding down with a compression spring 3. Polymerization was performed at 40°C for 12 hours, then at 45°C for 1 hour; 50
℃, 1 hour; 60℃, 1 hour; 65℃, 0.5 hour; 70
The temperature was increased stepwise as follows: 0.5 hours at 75 degrees Celsius; 0.5 hours at 75 degrees Celsius; 1 hour at 80 degrees Celsius. As a result, a transparent plastic lens 4 having a refractive index n _D of 1.581, an Abbe number of 33, and a pencil hardness of H was obtained. Example 3 5 parts of diisopropyl peroxycarbonate was added to 100 parts of a monomer mixture consisting of 40% of the compound (F) obtained in Example 1, 40% of diallyl phthalate, and 20% of benzyl methacrylate, and polymerization was carried out in the same manner as in Example 2. refractive index n _D 1.568, Atspe number 35, pencil hardness
A 2H clear plastic lens was obtained.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing an embodiment of a gasket used for manufacturing the plastic lens of the present invention. 1... Gasket, 2, 2'... Glass mold, 3
...Press spring, 4...Plastic cleanser.

Claims (1)

[Scope of Claims] 1 A homopolymer of a tetrabromophthalate ester derivative represented by the following structural formula, or the tetrabromophthalate derivative and an allyl ester,
It is made of a copolymer with at least one copolymer selected from the group consisting of acrylic esters and methacrylic esters, is transparent, has a refractive index of 1.56 to 1.58, has an Atsube number of 33 to 35, and has a pencil of H to 3H. Plastic lens with hardness.