JPS6320444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a high refractive index resin material with excellent transparency and particularly suitable for use in plastic lenses.

[Prior Art] Plastic lenses have come to be widely used as optical components, taking advantage of the advantages of being lightweight, easy to mold, and highly safe. There are already resins for plastic lenses such as polymethyl methacrylate and polydiethylene glycol bisallyl carbonate, which are also used for eyeglass lenses, but these resins have a low refractive index (n _D ≒ 1.49 to 1.50), so they are not suitable for use in cameras. When used as a lens, it is necessary to reduce the radius of curvature of the lens, resulting in larger aberrations than inorganic glass, making it difficult to increase the aperture and magnification. Polycarbonate (n _D = 1.58) and polystyrene (n _D = 1.59) are extremely familiar resins with a high refractive index, but their refractive index is still lower than that of glass. Furthermore, since these resins are thermoplastic resins, birefringence is likely to occur due to orientational strain during injection molding, resulting in a problem of variations in optical properties. Therefore, its use is limited to safety glasses, sunglasses, etc. Recently, proposals have been made to increase the refractive index of resins to produce high refractive index resins. For example, JP-A-57-2312
No. 57-54901, No. 57-28117, No. 56-
There are resins made of brominated compounds described in publications No. 166214 and No. 57-28118. However, since these resins are generally susceptible to desorption of bromine, there is a problem in that plastic lenses formed by injecting the monomer into a lens mold and then thermally curing are colored yellow. In order to avoid this problem, a colorless and transparent plastic lens can be obtained by lowering the curing temperature, but in this case, the curing time has to be longer, which poses problems in mass production. There is. Similarly, there are also problems in terms of light resistance, such as yellowing during use due to elimination of bromine.

On the other hand, one effective method for increasing the refractive index of plastic is to introduce heavy metals into the plastic. JP-A-56-147101 as technology related to metal-containing plastic lens materials
No. 57-5705, No. 57-28115, No. 57-28116
There are various publications, etc. However, monomers with covalently bonded metals or metal salts of carboxylic acids containing double bonds generally have poor solubility in styrene or styrene derivatives. Furthermore, even if only one type of metal salt of these carboxylic acids is used and copolymerized with a reactive monomer such as chlorostyrene, the transparency of the resin is poor;
There are still problems with plastic cleansing materials. Furthermore, in order to maintain a high degree of transparency of the resin, the amount of metal contained in the resin must be extremely small, making it impossible to sufficiently increase the refractive index of the plastic.

Therefore, the present inventors have conducted intensive research into a resin that contains the amount of metal necessary to exhibit a sufficient effect in increasing the refractive index of the resin and has a high degree of optical transparency. Ta. As a result, in addition to styrene and/or styrene derivatives and metal salts of acrylic acid and/or metal salts of methacrylic acid, a new combination of metal salts of carboxylic acids having a group containing a benzene nucleus and acrylic acid and/or methacrylic acid was added. The inventors have discovered that a resin with a high refractive index and excellent transparency can be obtained by using a copolymer, and have arrived at the present invention.

[Purpose of the invention]

An object of the present invention is to provide a metal-containing resin material for plastic lenses that maintains a high degree of optical transparency and has a high refractive index, specifically a refractive index of n _D =1.60 or more.

[Summary of the invention]

To summarize the present invention, the present invention relates to materials for plastic lenses, and each repeating unit represented by the following general formulas [1] to [4]: [In the formula, X represents hydrogen, chlorine, bromine, iodine, methoxy group, amino group, nitro group, phenyl group or phenoxy group, and a represents 1 or 2] from 45 to 68 mol%, [In the formula, M represents a metal element, R ₁ represents hydrogen or a methyl group, R ₂ represents a group containing a benzene nucleus, and n represents the oxidation number of the metal] from 3 to 25 mol%, 10 to 30 mol% of [in the formula, R ₁ has the same meaning as above], It is characterized by being a high refractive index copolymer resin containing 7 to 27 mol% of [in the formula, R ₁ and M have the same meanings as above, and m represents the oxidation number of the metal].

In the present invention, since the metal salt of (meth)acrylic acid hardly dissolves in the styrene and/or styrene derivative, a saturated or unsaturated hydrocarbon group containing a benzene nucleus is newly added to the monomer mixture. The solubility could be increased by adding metal salts of carboxylic acids.

Furthermore, it was found that metal salts of carboxylic acids containing benzene nuclei have the effect of increasing the refractive index of transparent resins. However, when producing plastic lenses by heating and curing these monomers, the transparency cannot be said to be sufficient. i.e. (meta)
When a metal salt of acrylic acid and a carboxylic acid containing a benzene nucleus is copolymerized with a reactive monomer, a metal salt of a carboxylic acid with an equimolar amount of carboxylic acid bound to the oxidation number of the metal (l mol of m-valent metal) is copolymerized with a reactive monomer. (ml mol) of carboxylic acid), the presence of fine particles in the resin causes transmitted light to be scattered, resulting in poor transparency. They discovered that this problem could be solved by increasing the number of moles of carboxylic acid that ionically bonds with the metal to more than an equimolar number, and decided to add (meth)acrylic acid.

However, if the amount of (meth)acrylic acid is too large, the resin will become cloudy. The amount of (meth)acrylic acid varies depending on the metal and the type of carboxylic acid containing a benzene ring, but the amount is 1.05 to make the number of moles of the total carboxylic acid equal to the number of moles of the metal.
It is preferable to mix the components at a ratio of ~2.0 times.

Examples of metal salts of carboxylic acids having a group containing a benzene nucleus in the present invention include metal salts of carboxylic acids represented by the following general formula.

[Formula ~, Y represents hydrogen, chlorine, bromine, iodine, methoxy group, amino group, nitro group, cyano group, _R3 represents an alkyl group, alkenyl group, aryl group, aralkyl group, cyclohexyl group, R ₄ and R ₅ represent hydrogen, methyl group, chlorine, bromine or cyano group, and R ₆ represents phenyl group, benzyl group or phenethyl group. Moreover, a represents 1 or 2, b represents 0-5, and d represents 1-5. ] Examples of formulas include benzoic acid, phenyl acetic acid,
Hydrocinnamic acid, 4-phenylbutyric acid, 5-phenylvaleric acid, o, m, p-chlorophenyl acetic acid, 2
-Phenylpropionic acid, 2-phenyl-n-butyric acid, 3-phenyl-n-butyric acid, etc. Examples of the formula include phenoxyacetic acid, 3-phenoxypropionic acid, o,p-chlorophenoxyacetic acid, and the like. Examples of formulas include monoethyl phthalate, monobenzyl phthalate, monoallyl phthalate, monovinyl phthalate, monocyclohexyl phthalate, monomethyl terephthalate, monoethyl terephthalate, monocyclohexyl terephthalate, and the like.
Examples of formulas include cinnamic acid, α-methylcinnamic acid, β-methylcinnamic acid, α-cyanocinnamic acid, and the like. Examples of formulas include monophenyl maleate, monobenzyl maleate, and the like. Examples of formulas include monophenyl fumarate, monobenzyl fumarate, and the like. Examples of formula XI include monophenyl itaconate, monobenzyl itaconate, and the like.
Examples of formula XII include 3-benzoyl acrylic acid. Examples of formulas include diphenylacetic acid, bis-(4-methoxyphenyl)acetic acid, and the like. These materials can be used alone or in combination of two or more.

In the present invention, when producing a metal salt of (meth)acrylic acid and a carboxylic acid having a group containing a benzene nucleus, known methods can be used. That is, after dissolving carboxylic acid in a polar solvent such as water or alcohol, or a non-polar solvent such as benzene or toluene, metal oxides,
The reaction is carried out by gradually adding metal compounds such as hydroxides, chlorides, nitrates, acetates, carbonates, etc. in solid form, or in the form of a solution or slurry at room temperature or in a heated state while stirring. let Metal salts of carboxylic acids are formed as precipitates or dissolved in solvents. The precipitated product is filtered and dried under vacuum with heating. A metal salt of a carboxylic acid dissolved in a solvent can be obtained by removing the solvent by distillation under reduced pressure.

The metal compounds used here include Pb, Ba,
Sr, Zn, Sn, Sb, Ca, La, Ti, Zr, Ta, Th,
Compounds such as Nb, Tl, Ge, etc. can be used. The metal salts of carboxylic acids prepared using these metal compounds may be used alone or in combination of two or more.

Examples of the polymerization initiator used when thermally curing the obtained monomer composition include benzoyl peroxide, lauroyl peroxide, diisopropyl peroxydicarbonate, dimyristyl peroxydicarbonate, and azobisisobutyronitrile. Conventional radical initiators can be used. In addition, when curing with ultraviolet rays, benzoin isopropyl ether, benzoin ethyl ether, benzoin isobutyl ether, α
-Allylbenzoin, α-methylbenzoin, benzophenone, benzyl 2-ethyl anthraquinone, etc. can be used. These ultraviolet curing type polymerization initiators can not only be used alone, but also thermosetting type polymerization initiators can be used in combination.

Furthermore, the production of the resin for plastic lenses according to the present invention involves pouring a mixture of the monomer composition and a polymerization initiator into a mold assembled with a mold (made of glass or metal) and a gasket. This is done by curing using means such as heating or ultraviolet irradiation. Of course, it is also possible to adopt a method of curing by irradiating with radiation without using an initiator.

[Embodiments of the invention]

EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. The physical properties of the high refractive index plastic lens resins obtained in Examples and Comparative Examples were measured using the following test methods.

(1) Refractive index (n _D ) and Atsube number The refractive index and Atsube number at 25°C were measured using an Atsube refractometer. α-Monobromonaphthalin was used as a contact liquid.

(2) Light transmittance Measured on a 2 mm thick test piece using a haze meter (manufactured by Suga Test Instruments Co., Ltd.).

Example 1 Mixed chlorostyrene (ortho/para = 60/40)
47 parts (by weight, same below), 13 parts of methacrylic acid,
33 parts of lead hydrocinnamate and 7 parts of methacrylic acid at 50℃
A transparent and clear monomer composition was obtained. Next, 0.25 parts of dimyristyl peroxydicarbonate (Perloil MSP manufactured by NOF Corporation) was added and mixed as a polymerization initiator to this monomer composition,
The mixture was poured into a casting mold consisting of two glass molds and a gasket. After curing by heating at 55°C for 4 hours and 90°C for 3 hours, the transparent polymer lens was taken out. The optical properties of the obtained polymer lens were n ²⁵ _D =1.613 and Abbe's number 31.7, and it was sufficiently suitable for practical use as a plastic lens.
Furthermore, the light transmittance of the polymer made using this monomer composition was 90%.

Example 2 30 parts of styrene, 50 parts of lead methacrylate, 10 parts of lead cinnamate, and 10 parts of methacrylic acid were mixed at 60°C to obtain a transparent and clear monomer composition. 0.2 parts of diisopropyl peroxycarbonate as a polymerization initiator was added and mixed to this monomer composition, and a plastic lens was cast in the same manner as in Example 1. The obtained polymer lens was transparent, and its optical properties were n ²⁵ _D =1.627 and Atsube's number 27.4. Moreover, the light transmittance of this polymer was 88%.

Example 3 Mixed chlorostyrene (ortho/para = 60/40)
50 parts, barium acrylate 15 parts, lead methacrylate
20 parts, barium salt of monobenzyl maleate 10
1 part and 5 parts of acrylic acid were mixed at 50°C to obtain a transparent and clear monomer composition. 0.3 parts of dimyristyl peroxydicarbonate as a polymerization initiator was added and mixed to this monomer composition, and a plastic lens was cast in the same manner as in Example 1. The obtained polymer lens is transparent and its optical properties are n ²⁵ _D
= 1.613, Atsbe's number was 29.6. Moreover, the light transmittance of this polymer was 90%.

Example 4 Mixed chlorostyrene (ortho/para=60/40)
50 parts of lanthanum methacrylate, 20 parts of lead methacrylate, 20 parts of lead salt of monoethyl phthalate, and 5 parts of acrylic acid were mixed at 60°C to obtain a transparent and clear monomer composition. 0.25 parts of dimyristyl peroxydicarbonate as a polymerization initiator was added and mixed to this monomer composition, and a plastic lens was cast in the same manner as in Example 1. The obtained polymer lens was transparent and its optical properties were n ²⁵ _D =1.622 and Utzbe number 30.5. Moreover, the light transmittance of this polymer was 88%.

Example 5 Mixed chlorostyrene (ortho/para=60/40)
47 parts of lead methacrylate, 24 parts of 3-phenoxypropionic acid, and 5 parts of methacrylic acid were mixed at 50°C to obtain a transparent and clear monomer composition. Example 1 0.25 parts of dimyristyl peroxydicarbonate was added as a polymerization initiator to this monomer composition and mixed.
A plastic lens was cast and molded in the same manner as described above. The obtained polymer lens was transparent, and its optical properties were n ²⁵ _D =1.614 and Atsube's number 32.0.
Moreover, the light transmittance of this polymer was 89%.

Example 6 47 parts of bromostyrene, 23 parts of lead methacrylate, 16 parts of lead salt of monobenzyl fumarate, 14 parts of methacrylic acid
The two parts were mixed at 50°C to obtain a transparent and clear monomer composition. 0.2 parts of diisopropyl diperoxycarbonate as a polymerization initiator was added and mixed to this monomer composition, and a plastic lens was cast in the same manner as in Example 1. The obtained polymer lens is transparent and its optical properties are n ²⁵ _D = 1.613 Atsube number
It was 31.2. The light transmittance of this polymer was 89%.

Example 7 Mixed chlorostyrene (ortho/para = 60/40)
47 parts of lead methacrylate, 15 parts of lead salt of monobenzyl itaconate, and 15 parts of methacrylic acid were mixed at 50°C to obtain a transparent and clear monomer composition. To this composition, 0.3 part of dimyristyl peroxydicarbonate was added and mixed as a polymerization initiator. A plastic lens was obtained in the same manner as in Example 1. The obtained polymer lens is transparent and its optical properties are
n ²⁵ _D = 1.608 and Atsbe number 32.1. The light transmittance of this polymer was 90%.

Example 8 Mixed chlorostyrene (ortho/para = 60/40)
47 parts of lead methacrylate, 16 parts of lead 3-benzoyl acrylate, and 14 parts of methacrylic acid were mixed at 50°C to obtain a transparent and clear monomer composition. Example 1 0.25 parts of dimyristyl peroxydicarbonate was added as a polymerization initiator to this monomer composition and mixed.
A plastic lens was cast and molded in the same manner as described above. The obtained polymer lens was transparent, and its optical properties were n ²⁵ _D =1.609 and Atsube number 32.0.
Moreover, the light transmittance of this polymer was 90%.

Example 9 Mixed chlorostyrene (ortho/para=60/40)
47 parts of lead methacrylate, 20 parts of lead salt of bis-(4-methoxyphenyl)acetic acid, and 9 parts of methacrylic acid were mixed at 60°C to obtain a transparent monomer composition. 0.25 parts of dimyristyl peroxydicarbonate as a polymerization initiator was added and mixed to this monomer composition, and a plastic lens was cast in the same manner as in Example 1. The obtained polymer lens is transparent and its optical properties are n ²⁵ _D = 1.618, Atsube number
It was 31.5. Also, the light transmittance of this polymer is 89
It was %.

Example 10 Mixed chlorostyrene (ortho/para = 60/40)
47 parts of lead methacrylate, 30 parts of parachlorophenylacetic acid, and 7 parts of methacrylic acid were mixed at 50°C to obtain a transparent monomer composition. Next, 0.25 parts of dimyristyl peroxydicarbonate was added as a polymerization initiator to this monomer composition and mixed.
A plastic lens was cast and molded in the same manner as described above. The obtained polymer lens was transparent, had optical properties of n ²⁵ _D =1.616, and an Abbé number of 31.5, and was sufficiently suitable for practical use as a plastic lens. Moreover, the light transmittance of this polymer was 89%.

Comparative example 1 Mixed chlorostyrene (ortho/para = 60/40)
60 parts of lead methacrylate and 40 parts of lead methacrylate were mixed at 60℃.
Lead methacrylate was not completely dissolved and remained partially as a precipitate. Therefore, the precipitate was removed by heating this monomer composition. Thereafter, 0.25 parts of dimyristyl peroxydicarbonate as a polymerization initiator was added and mixed to 100 parts of the monomer composition, and the mixture was poured into a casting mold in the same manner as in Example 1. After curing by heating at 55° C. for 4 hours and 100° C. for 3 hours, the polymer lens was taken out. The obtained polymeric lens was white and translucent and could not be used as a plastic lens.

Comparative example 2 Mixed chlorostyrene (ortho/para = 60/40)
60 parts, lead methacrylate 20 parts, lead hydrocinnamate 20 parts
parts were mixed at 50°C to obtain a monomer composition. This monomer composition did not form a precipitate, but was a slightly cloudy solution. Comparative Example 1: 0.25 parts of dimyristyl peroxydicarbonate was added as a polymerization initiator to 100 parts of this monomer composition.
A plastic lens was cast and molded in the same manner as described above. The obtained polymer lens was slightly cloudy and was not suitable as a plastic lens. The light transmittance of this polymer was 60%.

〔Effect of the invention〕

As described above, styrene and/or a styrene derivative and a metal salt of acrylic acid and/or a metal salt of methacrylic acid are copolymerized with a metal salt of a carboxylic acid containing a benzene nucleus and acrylic acid and/or methacrylic acid. This has made it possible to produce high refractive index plastic lenses with a high degree of optical transparency. Furthermore, since the resin of the present invention is a three-dimensionally crosslinked polymer formed by ionic bonding of metals, it not only has good scratch resistance but also has various properties such as being able to be ground with a diamond grindstone.

Claims (1)

[Claims] 1. Each repeating unit represented by the following general formulas [1] to [4]: [In the formula, X represents hydrogen, chlorine, bromine, iodine, methoxy group, amino group, nitro group, phenyl group or phenoxy group, and a represents 1 or 2] from 45 to 68 mol%, [In the formula, M represents a metal element, R ₁ represents hydrogen or a methyl group, R ₂ represents a group containing a benzene nucleus, and n represents the oxidation number of the metal] from 3 to 25 mol%, 10 to 30 mol% of [in the formula, R ₁ has the same meaning as above], A material for a plastic lens, characterized in that it is a high refractive index copolymer resin containing 7 to 27 mol% of [in the formula, R ₁ and M have the same meanings as above, and m represents the oxidation number of the metal].