JPH0430410B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an optical material, and more particularly to a method for producing an optical material that has low dispersion, a high refractive index, little shrinkage during cast polymerization, and excellent moisture absorption resistance. Plastic optical materials have advantages over glass materials, such as being lightweight, having high impact resistance, requiring no polishing and being easy to mass produce, and allowing mass production of aspherical lenses. However, on the other hand, the range of refractive index selection is smaller than that of glass ones.
It has drawbacks such as high hygroscopicity, and these drawbacks have hitherto been a factor inhibiting the use of plastic optical materials. In particular, plastic optical materials with low dispersion and high refractive index have not been available so far, and there has been a demand for their development. An object of the present invention is to provide a method for producing an optical material that eliminates the drawbacks of the above-mentioned prior art, has low dispersion, high refractive index, has little shrinkage during cast polymerization, and has excellent moisture absorption resistance. It is in. In order to achieve the above object, the present inventors have conducted intensive research and found that casting molding is possible by using a specific compound represented by the general formula () or () below as an acrylate monomer containing an olefinic group. The present inventors have discovered that it is possible to obtain an optical material that has improved polymerization shrinkage properties, moisture absorption resistance, birefringence, etc., has low dispersion comparable to that of methyl methacrylate, and has a high refractive index, and has arrived at the present invention. . The present invention is based on the general formula () (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 1 to 5 carbon atoms or an alkylene oxide group, R ₃ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is 1 or 2 carbon atoms. (means an integer)
Compound and/or general formula () represented by (wherein R ₁ , R ₃ and n have the above meanings)
The present invention relates to a method for producing an optical material, which is characterized by carrying out radical polymerization using a compound represented by the following as a main monomer component. The compound of general formula () or (), which is the main monomer component used in the present invention, can be easily obtained by esterifying a diol derivative derived from dicyclopentadiene or tricyclopentadiene with methacrylic acid or acrylic acid. can be manufactured. As a compound of general formula (), for example, etc. can be mentioned. Further, as a compound of the general formula (), for example, (Bis(methacryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane) (Bis(acryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane) ( ^bis (methacryloxymethyl)pentacyclo[ ^{6,5,12.6,02.7,09.13 ]} pentadecane), etc. In addition to these compounds of general formula () or (), other monomers may be used in combination, if desired. The monomer used in combination with these may be any monomer component that has radical polymerizability and does not impair transparency after polymerization, such as esters of acrylic acid or methacrylic acid such as methyl methacrylate, cyclohexyl methacrylate, and adamantyl methacrylate, and styrene. , α-methylstyrene, p-
Aromatic vinyl compounds such as methylstyrene, bromostyrene, and vinylnaphthalene; esters of polyhydric alcohols such as ethylene glycol, diethylene glycol, and pentaerythritol, and methacrylic acid or acrylic acid; alkyl allyl ethers such as allyl diglycol carbonate; Diallyl phthalate, diallyl isophthalate, etc. are used. The types and amounts of these monomers used are as follows:
Various selections can be made depending on the refractive index and heat resistance required for the optical material, but from the viewpoint of shrinkage during cast polymerization, for 10 parts by weight of the compound of general formula () or (), preferably 100
It is used in an amount of less than 10 parts by weight, more preferably less than 10 parts by weight. In the present invention, the optical material is obtained, for example, by polymerizing the monomer components using a known radical polymerization method, such as a method of polymerizing using a radical polymerization initiator or a method of polymerizing by irradiating ultraviolet rays or radiation. The radical polymerization initiator is not particularly limited, and known compounds can be used, and it is selected depending on the desired reaction temperature. For example, benzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxydicarbonate,
Peroxides such as methyl ethyl ketone peroxide and lauroyl peroxide, azo compounds such as azobisisobutyronitrile, and the like are used. When curing using means such as light or ultraviolet irradiation, an initiator and/or sensitizer may be used as necessary, such as acetophenone, benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, Benzoin isopropyl ether and the like are used. The polymerization method in the present invention is not particularly limited,
Known polymerization methods, such as cast polymerization, are used. According to this method, the monomer component containing a radical polymerization initiator is injected between molds held, for example, by a gasket or a spacer, and polymerized. Alternatively, the monomer components may be preliminarily polymerized in the presence of a polymerization initiator and then cast polymerized. During the polymerization reaction, the reaction temperature when heating varies depending on the catalyst used, but it is generally preferable to start the polymerization at a relatively low temperature and gradually raise the temperature to effect curing. During the polymerization reaction, additives such as a mold release agent, an ultraviolet absorber, an antioxidant, an anti-coloring agent, an antistatic agent, a fluorescent dye, and various stabilizers may be added as necessary. Note that these additives may be added after polymerization. The optical material made of a radical polymer obtained by the method of the present invention uses a specific compound represented by the general formula () or (), which is a diallyl monomer containing two olefinic groups, as a raw material. It has significantly improved polymerizability and birefringence during casting, has low dispersion and impact resistance comparable to diethylene glycol bisallyl carbonate, and also has high refractive index and heat resistance comparable to diallyl phthalate. are doing.
In addition, in the present invention, when producing an optical material, a compound represented by the general formula () and a general formula ()
You may use a mixture of the compounds represented by. Therefore, the optical material of the present invention can be used, for example, for eyeglasses,
For still cameras, video cameras, telescopes,
Transmits light through lenses such as lenses for concentrating sunlight, prisms, light guide elements such as optical waveguides, disks such as video disks, compact disks, write-once optical disks, and erasable and rewritable optical disks. Alternatively, it can be suitably used as a material that requires a reflective function. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 A monomer solution prepared by dissolving 0.1 g of isobisisobutyronitrile in 20 g of bis(methacryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane was placed between two glass plates and silicon. The mixture was poured into a mold equipped with a rubber gasket, heated and cured at 80°C for 6 hours at 100°C for 2 hours under a nitrogen atmosphere, and then released from the mold to obtain Polymer A. Example 2 Bis(methacryloxymethyl)pentacyclo[ ^6,5 ,
Polymer B ^was obtained in the same manner as ⁱⁿ Example ¹ except that pentadecane was used. Example 3 Instead of bis(methacryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane, Polymer C was prepared in the same manner as in Example 1.
I got it. Example 4 Polymer D was obtained in the same manner as in Example 1 except that 70 parts of bis(methacryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane and 30 parts of methyl methacrylate were used. Example 5 60 parts of bis(methacryloxymethyl)tricyclo[5,2,1,0 ^2.6 ]decane and 40 parts of styrene
Polymer E was obtained in the same manner as in Example 1 except that the same procedure was used as in Example 1. About the refractive index, dispersibility, polymerization shrinkage rate, surface hardness, water absorption, birefringence, heat distortion temperature (heat resistance) and impact resistance of the polymers (A to E) obtained in Examples 1 to 5. Tested. The results obtained are shown in Table 1. For comparison, diethylene glycol bisallyl carbonate (PPG product) (Comparative Example 1)
Table 1 also shows the test results for compounds obtained by polymerizing diallyl phthalate (Comparative Example 2), methyl methacrylate (Comparative Example 3), or styrene (Comparative Example 4) in the same manner as in Example 1. Shown.

【table】

[Table] As is clear from the results in Table 1, the polymer obtained by the production method of the present invention has low dispersion, high refractive index, little shrinkage during cast polymerization, and moisture absorption resistance. It is excellent.

Claims (1)

[Claims] 1 General formula () (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 1 to 5 carbon atoms or an alkylene oxide group, R ₃ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is 1 or 2 carbon atoms. (means an integer)
Compound and/or general formula () represented by (wherein R ₁ , R ₃ and n have the above meanings)
A method for producing an optical material, characterized by carrying out radical polymerization using a compound represented by as a main monomer component.