Composition for plastic lenses

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to compositions useful in the making of plastic lenses having high thermal resistance, high impact resistance, low water absorption and good moldability.
2. Description of the Prior Art
Because of their unique properties such as easy moldability and light weight, plastic lenses have come to be widely used in optical products. In particular, it is desirable that eyeglasses are light in weight. In recent years, therefore, a resin comprising diethylene glycol bisallyl carbonate (commercially available under the tradename of CR-39 from PPG Co., Ltd.) is being used as the chief material for the making of plastic eyeglasses.
However, high refractive indices and high productivity have lately come to be required of plastic lenses. As a result, plastic lenses made by using various monomers and oligomers in place of CR-39 have been proposed.
Important properties required of plastic lenses include high thermal resistance, high impact resistance, low water absorption, molding surface accuracy, dyeability and the like. Conventionally, monomers and oligomers capable of imparting highly elastic structures such as the ether, urethane, ester and carbonate linkages have been used as components for improving impact resistance and dyeability. Among others, the use of low-viscosity di(meth)acrylates having an ether linkage in the molecule and capable of improving casting workability has been proposed (Japanese Patent Laid-Open No. 16813/'89).
Typical examples of such di(meth)acrylate monomers capable of producing a polyether structure are polyethylene glycol di(meth)acrylates and polypropylene glycol di(meth)acrylates. When these monomers are used, the impact resistance and dyeability of the resulting lenses are improved in proportion to the increasing number of repeating ethylene oxide or propylene oxide units.
On the other hand, however, this approach has posed a problem concerning the retention of high thermal resistance, low water absorption and high surface accuracy which are required of lenses. In order to achieve high thermal resistance and low water absorption, it generally suffices to impart low water absorption properties to the polymer. Improvement of the low water absorption properties of a polymer has been achieved by introducing a hydrocarbon chain, aromatic ring or halogen atom into the molecule thereof (Japanese Patent Laid-Open No. 66401/'82). This method brings about high thermal resistance and low water absorption, but causes a reduction in impact resistance and dyeability.
In order to solve the above-described problems, the present inventors have made intensive studies and have found that a certain polybutylene glycol dimethacrylate is a monomer capable of producing a polymer having a well-balanced combination of impact resistance and water absorption, and a certain composition containing this monomer can yield a product having high impact resistance and low water absorption. Moreover, it has also been found that, by applying this composition to the making of plastic lenses, there can be obtained plastic lenses having high impact resistance, good dyeability, high thermal resistance and low water absorption. However, this composition fails to achieve satisfactorily high surface accuracy (i.e., coincidence between the lens curvature and the design curvature) which is a property required of lenses.
The present inventors continued to make intensive studies and have found a composition containing an urethane poly(meth)acrylate or an epoxy poly(meth)acrylate for improving thermal resistance, a polybutylene glycol di(meth)acrylate for improving impact resistance, low water absorption and dyeability, and a mono(meth)acrylate of alicyclic hydrocarbon monoalcohol or aromatic monoalcohol for improving surface accuracy which can yield excellent lens products. Accordingly, the present inventors completed the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a composition for plastic lenses which can be polymerized with high-energy radiation in a short period of time to yield plastic lenses having high thermal resistance, high impact resistance, good dyeability and low water absorption.
It is another object of the present invention to provide a composition for plastic lenses which can yield plastic lenses (in particular, concave lenses) having high surface accuracy.
The above objects of the present invention are accomplished by providing a composition for plastic lenses which comprises
(A) 10 to 60 parts by weight of a polybutylene glycol di(meth)acrylate represented by the general formula (I): ##STR2## where R.sup.1 is hydrogen or methyl, and n is an integer of 5 to 16;
(B) 20 to 80 parts by weight of at least one compound selected from the group consisting of a urethane poly(meth)acrylate having two or more (meth)acryloyloxy groups in the molecule, and an epoxy poly(meth)acrylate having two or more (meth)acryloyloxy groups in the molecule;
(C) 5 to 60 parts by weight of at least one mono(meth)acrylate selected from the group consisting of compounds represented by the general formulae (II), (III), (IV) and (V): ##STR3## wherein R.sup.2 is hydrogen or methyl, R.sup.3 is an alicyclic hydrocarbon radical having 5 to 16 carbon atoms, R.sup.4 is hydrogen or methyl, R.sup.5 is --CH.sub.2 --, --CH.sub.2 CH.sub.2 --O--, ##STR4## or --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 --O--, X is chlorine, bromine or iodine, m is an integer of 0 to 3, p is an integer of 0 to 5, q is an integer of 0 to 4, and r is an integer of 0 to 3; and
(D) 0 to 60 parts by weight of a compound having at least one polymerizable double bond in the molecule,
with the total amount of components (A), (B), (C) and (D) being 100 parts by weight.
In the compositions of the present invention, component (A) has a favorable effect chiefly on impact resistance, water absorption and dyeability, component (B) has a favorable effect chiefly on thermal resistance, and component (C) has a favorable effect chiefly on surface accuracy. As a result of the cooperation of these effects, the compositions of the present invention are very excellent compositions for plastic lenses from a generalized point of view.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The polybutylene glycol di(meth)acrylate (A) of the general formula (I), which constitutes a first component in the compositions of the present invention, is a polybutylene glycol having a degree of polymerization of 5 to 16 and whose ends are terminated with two acrylic acid or methacrylic acid molecules. As used herein, the term "degree of polymerization" means the number (n) of repeating units represented by the formula --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 O--. If the degree of polymerization is less than 5, sufficient flexibility will not be obtained. If it is greater than 16, the resulting polymer will show an increase in water absorption and a reduction in cross-linking density, resulting in reduced hardness and thermal resistance. Moreover, the monomer will show an increase in viscosity, resulting in reduced casting workability. Preferably, the degree of polymerization is in the range of 7 to 12. It is to be understood that, since a polybutylene glycol dimethacrylate is generally a mixture of polymeric species having normally distributed degrees of polymerization, the degree of polymerization (n) used herein means a median.
The polybutylene glycol di(meth)acrylates which are useful in the compositions of the present invention can readily be prepared by the condensation reaction of a polybutylene glycol (obtained, for example, by the ring opening polymerization of tetrahydrofuran) with acrylic acid or methacrylic acid, or by the ester interchange reaction of a polybutylene glycol with methyl acrylate or methyl methacrylate. However, the use of an ester interchange reaction is preferred because it produces a colorless and transparent monomer.
Typical examples of the polybutylene glycol di(meth)acrylate (A) include heptabutylene glycol di(meth)acrylate, octabutylene glycol di(meth)acrylate, nonabutylene glycol di(meth)acrylate, decabutylene glycol di(meth)acrylate, undecabutylene glycol di(meth)acrylate and dodecabutylene glycol di(meth)acrylate.
The compound (B) constituting a second component in the compositions of the present invention is selected from the group consisting of a urethane poly(meth)acrylate having two or more (meth)acryloyloxy groups in the molecule, and an epoxy poly(meth)acrylate having two or more (meth)acryloyloxy groups in the molecule.
The compound (B) constituting the second component is used to improve the thermal resistance of the resulting lenses, because lenses formed by using only the polybutylene di(meth)acrylate (A) constituting the first component will fail to have satisfactory thermal resistance.
Useful urethane poly(meth)acrylates having two or more (meth)acryloyloxy groups in the molecule, which can be used as the compound (B), include products obtained by the urethane-forming reaction of a (meth)acrylate containing a hydroxyl group with a polyisocyanate having two or more isocyanate groups in the molecule.
Specific examples of the polyisocyanate having two or more isocyanate groups in the molecule include aliphatic, aromatic and alicyclic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 1,3-bis(.alpha.,.alpha.-dimethylisocyanatomethyl)benzene, diphenylmethane diisocyanate, m-phenylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate and biphenyl diisocyanate. There can also be used those compounds having two or more isocyanate groups in the molecule which are obtained by reacting such a polyisocyanate with a compound having at least two active hydrogen atoms arising from the amino group, the hydroxyl group, the carboxyl group, water or the like; the trimers, tetramers and pentamers of the foregoing diisocyanates; and the like.
The hydroxyl-containing (meth)acrylates which can be reacted with the above-described polyisocyanates include hydroxyl-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; the adducts of (meth)acrylic acid with monoepoxy compounds such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether and glycidyl methacrylate; mono(meth)acrylic esters of polyethylene glycol, polypropylene glycol and the like; mono(meth)acrylic esters of polycaprolactonediols (n=1 to 5); and the like.
The addition reaction of a polyisocyanate with a hydroxyl-containing (meth)acrylate can be carried out according to any conventional procedure. For Example, this can be done by adding a mixture of a hydroxyl-containing (meth)acrylate and a catalyst (e.g., di-n-butyltin laurate) dropwise to a polyisocyanate at a temperature of 50.degree. to 90.degree. C.
In the compositions of the present invention, the above-defined urethane poly(meth)acrylates may be used alone or in admixture of two or more. However, for the reason that the plastic lenses formed by curing are colorless and transparent and have high thermal resistance, it is especially preferable to use a urethane poly(meth)acrylate which is an adduct of 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate with isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, 1,3-bis(.alpha.,.alpha.-dimethylisocyanatomethyl)benzene, tolylene diisocyanate or naphthalene diisocyanate.
Useful epoxy poly(meth)acrylates having two or more (meth)acryloyloxy groups in the molecule, which can be used as the compound (B), include products obtained by the glycidyl ring opening reaction of an epoxy compound having two or more glycidyl groups in the molecule with (meth)acrylic acid or a compound having (meth)acryloyloxy and carboxyl groups in the molecule.
The epoxy compounds (i.e., the Epoxy compounds having two or more glycidyl groups in the molecule) which can be used in the above-described ring opening reaction to form epoxy poly(meth)acrylates include aliphatic epoxy compounds such as 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, nonaethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycodl diglycidyl ether, tripropylene glycol diglycidyl ether, tetrapropylene glycol diglycidyl ether, nonapropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, diglycidyl ether of neopentyl glycol hydroxypivalate, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol triglycidyl ether, pentaerythritol diglycidyl ether, pentaerythritol tetraglycidyl ether, dipentaerythritol pentaglycidyl ether, dipentaerythritol hexaglycidyl ether, sorbitol tetraglycidyl ether, diglycidyl ether of tris(2-hydroxyethyl) isocyanurate, and triglycidyl ether of tris(2-hydyroxyethyl) isocyanurate; alicyclic epoxy compounds such as isophoronediol diglycidyl ether, 1,4-bis(hydroxymethyl)cyclohexane diglycidyl ether and bis-(4-glycidyloxycyclohexyl)propane, aromatic epoxy compounds such as resorcinol diglycidyl ether, 2,2-bis(4-glycidyloxyphenyl) propane (obtained by the condensation of bisphenol A with epichlorohydrin), 2,2-bis (4-glycidyloxyphenyl) propane (obtained by the condensation of bisphenol F with epichlorohydrin), 2,2-bis(4-glycidyloxyphenyl)sulfane (obtained by the condensation of bisphenol S with epichlorohydrin), 2,2-bis(4-glycidyloxy-3,5-dibromophenyl)propane, the condensation products of bis(3,5-dimethyl-4-hydroxyphenyl)sulfone, bis(3-methyl-4-hydroxyphenyl)sulfone or bis(3-phenyl-4-hydroxyphenyl)sulfone with epichlorohydrin, the condensation product of 2,6-xylenol dimer with epichlorohydrin, diglycidyl o-phthalate, phenolic novolak polyglycidyl ether and cresylic novolak polyglycidyl ether; and the like.
The compounds which can be reacted with the above-described epoxy compounds include acrylic acid, methacrylic acid, carboxyl-containing (meth)acrylates obtained by the reaction of hydroxyethyl (meth)acrylate with an acid anhydride such as o-phthalic anhydride, and carboxyl-containing (meth)acrylates obtained by the reaction of glycidyl (meth)acrylate with a compound having two or more carboxyl groups in the molecule, such as adipic acid.
The reaction of an epoxy compound with a carboxyl-containing (meth)acrylate can be carried out, for example, by mixing both reactants, adding thereto a catalyst comprising a tertiary amino compound (e.g., dimethylaminoethyl- methacrylate) or a quaternary amine salt (e.g., benzyltrimethylammonium chloride), and heating the resulting reaction mixture at a temperature of 60.degree. to 110.degree. C.
In the compositions of the present invention, the above-defined epoxy poly(meth)acrylates may be used alone or in admixture of two or more. However, for the reason that the plastic lenses formed by curing are colorless and transparent and have high thermal resistance, it is especially preferable to use an epoxy poly(meth)acrylate which is a reaction product of acrylic acid or methacrylic acid with 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, triglycidyl ether of tris(2-hydroxyethyl) isocyanurate, 2,2-bis(4-glycidyloxycyclohexyl)propane, 2,2-bis(4-glycidyloxyphenyl)propane, 2,2-bis(4-glycidyloxyphenyl)sulfone or 2,2-bis(4-glycidyloxy-3,5-dibromophenyl)propane.
The mono(meth)acrylate (C) constituting a third component in the compositions of the present invention is selected from the group consisting of compounds represented by the general formulae (II), (III), (IV) and (V). This mono(meth)acrylate (C) is used to improve the surface accuracy of the resulting lenses, because lenses formed by using only the first and second components will fail to have satisfactory surface accuracy.
The compounds which can be used as the mono(meth)acrylate (C) include ones represented by the general formula (II): ##STR5## where R.sup.2 is hydrogen or methyl, and R.sup.3 is an alicyclic hydrocarbon radical having 5 to 16 carbon atoms. Specific examples of these compounds are cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, norbornyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate and tricyclo[5.2.1.0.sup.2,6 ]decan-8-yl (meth)acrylate. These compounds may be used alone or in admixture of two or more. Especially preferred are cyclohexyl (meth)acrylate, norbornyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate and tricyclo[5.2.1.0.sup.2,6 ]-decan-8-yl (meth)acrylate.
The compounds which can be used as the mono(meth)acrylate (C) also include ones represented by the general formulae (III), (IV) and (V): ##STR6## where R.sup.4 is hydrogen or methyl, R.sup.5 is --CH.sub.2 --, --CH.sub.2 CH.sub.2 --O--, ##STR7## or --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 --O--, X is chlorine, bromine or idodine, m is an integer of 0 to 3, p is an integer of 0 to 5, q is an integer of 0 to 4, and r is an integer of 0 to 3 . These compounds are mono(meth)acrylates of monoalcohols having an aromatic hydrocarbon radical or a halogenated aromatic hydrocarbon radical.
These compounds can be prepared by reacting (meth)acrylic acid with a monoalcohol as described above or a product obtained by the ring opening addition of ethylene oxide, propylene oxide or tetrahydrofuran to a monoalcohol as described above.
Specific examples of the compounds represented by the general formulae (III), (IV) and (V) include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxy-2-methyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, phenyl-di(oxyethyl) (meth)acrylate, phenyl-tri(oxyethyl) (meth)acrylate, phenyl-di(2-methyloxyethyl) (meth)acrylate, phenyl-tri(2-methyloxyethyl) (meth)acrylate, phenoxybutyl (meth)acrylate, phenyl-di(oxybutyl) (meth)acrylate, phenyl-tri(oxybutyl) (meth)acrylate, 2-phenylphenyl (meth)acrylate, 4-phenylphenyl (meth)acrylate, 2-phenylphenoxyethyl (meth)acrylate, 4-phenylphenoxyethyl (meth)acrylate, 2-phenylphenyl-2-methoxyethyl (meth)acrylate, 4-phenylphenyl-2-methyloxyethyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 3-(4-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, 1-naphthyloxyethyl (meth)acrylate, 2-naphthyloxyethyl (meth)acrylate, 1-naphthyl-di(oxyethyl) (meth)acrylate, 2-naphthyl-di(oxyethyl) (meth)acrylate, 1-naphthyl-2-methyloxyethyl (meth)acrylate, 2-naphthyl-2-methyloxyethyl (meth)acrylate, 3-(1-naphthyl)-2-hydroxypropyl (meth)acrylate, 3-(2-naphthyl)-2-hydroxypropyl (meth)acrylate, 2-bromophenyl (meth)acrylate, 4-bromophenyl (meth)acrylate, 2,4-dibromophenyl (meth)acrylate, 2,4,6-tribromophenyl (meth)acrylate, 2,3,4,5,6-pentabromophenyl (meth)acrylate, 2,4-dibromophenoxyethyl (meth)acrylate, 2,4,6-tribromophenyl-di(oxyethyl) (meth)acrylate, 2,4,6-tribromophenyl-2-methyloxyethyl (meth)acrylate, 2-bromobenzyl (meth)acrylate, 4-bromobenzyl (meth)acrylate, 2,4-dibromobenzyl (meth)acrylate, 2,4,6-tribromobenzyl (meth)acrylate, 2,3,4,5,6,-pentabromobenzyl (meth)acrylate, 2-chlorophenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, 2,4-dichlorophenyl (meth)acrylate, 2,4,6-trichlorophenyl (meth)acrylate, 2,3,4,5,6-pentachlorophenyl (meth)acrylate, 2,4-dichlorophenyloxyethyl (meth)acrylate, 2,4,6-trichlorophenyloxyethyl (meth)acrylate, 2,4,6-trichlorophenyl-di(oxyethyl) (meth)acrylate, 2,4,6-trichlorophenoxy-2-methyloxyethyl (meth)acrylate, 3-(2,3,4,5,6-pentabromophenyl)-2-hydroxypropyl (meth)acrylate, 2-phenyl-4-bromphenyl (meth)acrylate, 2-(4-bromopheny)-4,6-dibromophenyl (meth)acrylate, 2-(4-chlorophenyl)- 4,6-dichlorophenyl (meth)acrylate, 2-phenyl-4-bromophenyloxyethyl (meth)acrylate, 2-(4-bromophenyl)-4,6-dibromophenyloxyethyl (meth)acrylate, 2-(2,4,6-tribromophenyl)-4,6-dibromophenyl (meth)acrylate, 2-(2,4-dibromophenyl)-4,6-dibromophenyloxyethyl (meth)acrylate, 1-(4-chloronaphthyl)oxyethyl (meth)acrylate, 2-(4-chloronaphthyl)oxyethyl (meth)acrylate, 1-(4-bromonaphthyl)oxyethyl (meth)acrylate, 2-(4-bromonaphthyl)oxyethyl (meth)acrylate, 3-[1-(2-bromonapthyl)]-2-hydroxypropyl (meth)acrylate and 3-[2-(2-bromonaphthyl)]-2-hydroxypropyl (meth)acrylate.
As the mono(meth)acrylate represented by the general formulae (III), (IV) and (V) in the compositions of the present invention, the above-enumerated compounds may be used alone or in admixture of two or more. However, for the reason that the resulting lenses have high surface accuracy and are colorless and transparent, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, 2-phenylphenyl (meth)acrylate, 4-phenylphenyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 3-(4-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 1-naphthyloxyethyl (meth)acrylate, 2-naphthyloxyethyl (meth)acrylate, 2,4,6-tribromophenyl (meth)acrylate, 2,4,6-tribromophenoxyethyl (meth)acrylate, 2,4,6-tribromophenyl-di(oxyethyl) (meth)acrylate and 2,4,6-tribromobenzyl (meth)acrylate are preferred.
The compound (D) having at least one polymerizable double bond in the molecule, which constitutes a fourth component in the compositions of the present invention, is a component for imparting thereto high thermal resistance, high surface hardness and low viscosity. In particular, since a highly viscous urethane poly(meth)acrylate or epoxy poly(meth)acrylate is used in the compositions of the present invention, it is preferable to reduce the viscosity of the compositions as much as possible and thereby improve their casting workability. Accordingly, it is especially preferable to use a low-viscosity ester monomer as the compound (D).
Specific examples of the compound (D) include mono(meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, butoxyethyl (meth)acrylate, allyl (meth)acrylate, methallyl (meth)acrylate, glycidyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, dibromopropyl (meth)acrylate, N-vinyl-2-pyrrolidone (meth)acrylate, polyethylene glycol monoalkyl ether (meth)acrylates, polypropylene glycol monoalkyl ether (meth)acrylates, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate and phosphoethyl (meth) acrylate; di(meth)acrylates of poly (or mono)ethylene glycols, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, pentaethylene glycol di(meth)acrylate, and nonaethylene glycol di(meth)acrylate; di(meth)acrylates of poly (or mono)propylene glycols, such as propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate and nonapropylene glycol di(meth)acrylate; multifunctional (meth)acrylic compounds such as 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexamethylene glycol di(meth)acrylate, 1,14-tetradecamethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, the di(meth)acrylate of the adduct of caprolactone with neopentyl glycol hydroxypivalate, neopentyl glycol adipate di(meth)acrylate, dicyclopentenyl di(meth)acrylate, dicyclopentanyl di(meth)acrylate, 2-(2-hydroxy-1,1-dimethylethyl)-5-hydroxymethyl-5-ethyl-1,3-dioxane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, di(meth)acryloyloxyethyl isocyanurate, tris(meth)acryloyloxyethyl isocyanurate, 2,2-bis[4-(meth)acryloyloxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxydiethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxypentaethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxy-3,5-dibromophenyl]propane, 2,2-bis[4-(meth)acryloyloxydiethoxy-3,5-dibromophenyl]propane, 2,2-bis[4-(meth)acryloyloxypentaethoxy-3,5-dibromophenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxy-3,5-dimethylphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxy-3-phenylphenyl]propane, bis[4-(meth)acryloyloxyphenyl]sulfone, bis[4-(meth)acryloyloxyethoxyphen-vl]sulfone, bis[4-(meth)acryloyloxydiethoxyphenyl]sulfone, bis[4-(meth)acryloyloxypentaethoxyphenyl]sulfone, bis[4-(meth)acryloyloxyethoxy-3-phenylphenyl]sulfone, bis[4-(meth)acryloyloxyethoxy-3,5-dimethylphenyl]sulfone, bis[4-(meth)acryloyloxyphenyl]sulfide, bis[4-(meth)acryloyloxyethoxyphenyl]sulfide, bis[4-(meth)acryloyloxypentaethoxyphenyl]sulfide, bis[4-(meth)acryloyloxyethoxy-3-phenylphenyl]sulfide, bis[4-(meth)acryloyloxyethoxy-3,5-dimethylphenyl]sulfide, di[(meth)acryloyloxyethoxy]phosphate and tri[(meth)acryloyloxyethoy]phosphate; vinyl compounds such as styrene, vinyltoluene, chlorostyrene, bromostyrene, divinylbenzene, 1-vinylnaphthalene, 2-vinylnaphthalene and N-vinylpyrrolidone; allyl compounds such as diethylene glycol bisallyl carbonate, trimethylolpropane diallyl, diallyl phthalate and dimethallyl phthalate; and (meth)acrylic acid and its metallic salts such as barium, lead, antimony, titanium, tin and zinc (meth)acrylate. These compounds may be used alone or in admixture of two or more.
The compositions for plastic lenses in accordance with the present invention comprise 10 to 60 parts by weight of component (A), 20 to 80 parts by weight of component (B), 5 to 60 parts by weight of component (C), and 0 to 60 parts by weight of component (D), with the total amount of components (A), (B), (C) and (D) being 100 parts by weight. If the amount of component (A) used is less than 10 parts by weight, it will be impossible to impart sufficient impact resistance to the resulting lenses and control their water absorption. On the other hand, if it is greater than 60 parts by weight, the resulting lenses will be reduced in thermal resistance and surface hardness. Preferably, component (A) is used in an amount of 20 to 50 parts by weight. If the amount of component (B) used is less than 20 parts by weight, it will be impossible to impart sufficient thermal resistance to the resulting lenses. On the other hand, if it is greater than 80 parts by weight, the composition will have excessively high viscosity and hence reduced workability in casting operation. Preferably, component (B) is used in an amount of 30 to 60 parts by weight. If the amount of component (C) used is less than 5 parts by weight, the resulting lenses will have low surface accuracy. On the other hand, if it is greater than 60 parts by weight, the resulting lenses will be reduced in thermal resistance and toughness. Preferably, component (C) is used in an amount of I0 to 40 parts by weight. Although component (D) is not an essential component, this is used to further improve the thermal resistance and surface hardness of the resulting lenses and to reduce the viscosity of the composition and thereby improve its casting workability. Preferably, component (B) is used in an amount of 5 to 30 parts by weight.
If desired, the compositions for plastic lenses in accordance with the present invention may further contain various additives such as antioxidants, antiyellowing agents, ultraviolet light absorbers, bluing agents and pigments, so long as they do not impair the effects of the present invention.
The compositions for plastic lenses in accordance with the present invention can be prepared by mixing and stirring components (A), (B), (C) and (D) in the usual manner and incorporating various additives thereinto according to the need.
The compositions for plastic lenses in accordance with the present invention can be cured by means of a polymerization initiator. Useful polymerization initiators include, for example, organic peroxides such as benzoyl peroxide, tert-butyl peroxyisobutyrate and tert-butyl peroxy-2-ethylhexanoate; azo compounds such as 2,2'-azobisisobutyronitrile and 2,2,-azobis(2,4-dimethylvaleronitrile); and photopolymerization initiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, methyl phenylglyoxylate and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. These polymerization initiators may be used alone or in admixture of two or more. The amount of polymerization initiator used is generally in the range of 0.005 to 5 parts by weight per 100 parts by weight of the combined amount of components (A), (B), (C) and (D).
Lenses can be made, for example, by use of a mold comprising two mirror-polished glass plates and a gasket formed of an ethylene-vinyl acetate copolymer. A composition of the present invention is poured into the mold and cured either by irradiation with high-energy radiation from one side or both side of the mold, or by the application of heat. A combination of irradiation and heating may also be used. The mold may comprise two glass plates, a glass plate and a plastic plate, a glass plate and a metal plate, or a combination of them. Moreover, the gasket formed of the above-described thermoplastic resin may be replaced by an adhesive tape formed of polyester.
The present invention is further illustrated by the following examples and comparative examples. The abbreviations used for monomers are as follows:
Component (A)
9BGDM: nonabutylene glycol dimethacrylate.
12BGDM: dodecabutylene glycol dimethacrylate.
Component (B)
UDM1: a urethane dimethacrylate obtained by reacting isophorone diisocyanate with 2-hydroxypropyl methacrylate.
UDM2: a urethane dimethacrylate obtained by reacting 1,3-bis(.alpha.,.alpha.-dimethylisocyanatomethyl)benzene with 2-hydroxypropyl methacrylate.
UDA3: a urethane diacrylate obtained by reacting tolylene diisocyanate with 2-hydroxyethyl acrylate.
EDM1: an epoxy dimethacrylate obtained by reacting bisphenol A diglycidyl ether with methacrylic acid.
EDA2: an epoxy diacrylate obtained by reacting tetrabromobisphenol A diglycidyl ether with acrylic acid.
EDM3: an epoxy dimethacrylate obtained by reacting bisphenol S diglycidyl ether with methacrylic acid.
Component (C)
TCDM: tricyclo[5.2.1.0.sup.2,6 ]decan-8-yl methacrylate.
CHM: cyclohexyl methacrylate.
IBA: isobornyl acrylate.
ADM: adamantyl methacrylate.
PhM: phenyl methacrylate.
BPhM: 2-phenylphenyl methacrylate.
3BrPhM: 2,4,6-tribromophenoxyethyl acrylate.
HPM: 3-phenoxy-2-hydroxypropyl methacrylate.
BzM: benzyl methacrylate.
POM: phenoxyethyl methalcrylate.
Component (D)
HDDM: 1,6-hexamethylene glycol dimethacrylate.
HDDA: 1,6-hexamethylene glycol diacrylate.
DGBC: diethylene glycol bisallyl carbonate.
9EGDM: nonaethylene glycol dimethacrylate.
Synthesis Example 1 (synthesis of 9BGDM by ester interchange)
A 5-liter four-necked flask was charged with 2.0 kg of nonabutylene glycol having an average molecular weight of 680 (commercially available under the trade name of PTG-650SN from Hodogaya Chemicals Co., Ltd.), 2.0 kg of MMA, and 0.5 kg of hydroquinone monomethyl ether. Using 50 g of titanium tetra-n-butoxide as a catalyst, the reaction mixture was stirred at 100.degree.-120.degree. C. for 3 hours, during which time the methanol formed was azeotropically removed with MMA. After completion of the reaction, the excess MMA was distilled off under reduced pressure. The residue was mixed with 1 kg of toluene and washed with alkaline water. Then, the toluene was distilled off under reduced pressure to obtain 9BGDM.
The 9BGDM thus obtained was colorless and transparent. When analyzed by bromine addition, its purity was found to be 100%.
Synthesis Example 2 (synthesis of a urethane dimethacrylate)
A three-necked flask was charged with 222 parts of isophorone diisocyanate and 0.3 part of hydroquinone monomethyl ether. While this mixture was being stirred at 60.degree. C., a mixture of 302 parts of 2-hydroxypropyl methacrylate and 0.3 part of di-n-butyltin laurate was added dropwise thereto over a period of 3 hours. After completion of the addition, the reaction was continued at 70.degree. C. for an additional 8 hours to obtain a urethane dimethacrylate (UDM1).
Synthesis Example 3 (synthesis of an epoxy dimethacrylate)
A 5-liter three-necked flask was charged with 3015 g of bisphenol A diglycidyl ether (commercially available under the trade name of YD-8125 from Toto Kasei Co., Ltd.), 1485 g of methacrylic acid (commercially available from Mitsubishi Rayon Co., Ltd.), 45 g of benzyltrimethylammonium chloride as a catalyst, and 1 g of hydroquinone monomethyl ether as an inhibitor. When this reaction mixture was reacted at 70.degree. C. for 3 hours, at 80.degree. C. for 3 hours, and then at 110.degree. C. for 8 hours, its acid value reached 0.15. The reaction was stopped to obtain an epoxy dimethacrylate (EDM1).

EXAMPLE 1
35 g of 9BGDM, 40 g of UDM1, 20 g of TCDM, 5 g of HDDM, 0.03 g of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 0.1 g of tert-butyl peroxyisobutyrate, 0.05 g of 2-hydroxy-4-methoxybenzophenone, and 0.2 g of tridodecyl phosphate were mixed and stirred well at room temperature. Then, this mixture was deaerated by exposing it to a reduced pressure of 50 mmHg for 10 minutes.
A mirror-finished glass disk having an external diameter of 80 mm and a curvature of 386 mm, and a mirror-finished glass disk having an external diameter of 80 mm and a curvature of 65 mm were combined so as to give a concave lens having a thickness of 1.5 mm at its center. Then, these glass disks were surrounded by a polyvinyl chloride gasket to form a mold. The above composition was poured into this mold.
Subsequently, using 2 kW high-pressure mercury vapor lamps, both sides of the mold were irradiated with ultraviolet light in an amount of 2000 mJ/cm.sup.2, followed by heating at 130.degree. C. for 2 hours. Thereafter, the lens was removed from the mold and annealed by heating at 120.degree. C. for an hour. Lenses made in this manner were evaluated and the results of evaluation are shown in Table 1.
EXAMPLES 2-8
Lenses were made in the same manner as described in Example 1, except that monomers were used in the proportion shown in Table 1. These lenses were evaluated and the results of evaluation are also shown in Table 1.
COMPARATIVE EXAMPLE 1
100 g of diethylene glycol bisallyl carbonate (commercially available under the trade name of CR-39 from PPG Co., Ltd.) and 3 g of diisopropyl peroxypercarbonate were mixed and stirred well. Then, this mixture was poured into the same mold as used in Example 1, and cured by maintaining it at 45.degree. C. for 10 hours, at 60.degree. C. for 3 hours, at 80.degree. C. for 3 hours, and then at 95.degree. for 6 hours. Thereafter, the lens was removed from the mold and annealed by heating at 120.degree. C. for an hour. Lenses and flat disks made in this manner were evaluated and the results of evaluation are shown in Table 1.
COMPARATIVE EXAMPLES 2-8
Lenses were made in the same manner as described in Example 1, except that monomers were used in the proportion shown in Table 1. These lenses were evaluated and the results of evaluation are also shown in Table 1.
EXAMPLES 9-12 AND COMPARATIVE EXAMPLES 9-12
Lenses were made in the same manner as described in Example 1, except that a compound represented by the general formula (III), (IV) or (V) was used as component (C) and monomers were used in the proportion shown in Table 2. These lenses were evaluated and the results of evaluation are also shown in Table 2.
EXAMPLES 13-16 AND COMPARATIVE EXAMPLES 13-16
Lenses were made in the same manner as described in Example 1, except that an epoxy poly(meth)acrylate was used as component (B) and monomers were used in the proportion shown in Table 3. These lenses were evaluated and the results of evaluation are also shown in Table 3.
EXAMPLES 17-22 AND COMPARATIVE EXAMPLES 17-21
Lenses were made in the same manner as described in Example 1, except that an epoxy poly(meth)acrylate was used as component (B), a compound represented by the general formula (III), (IV) or (V) was used as component (C), and monomers were used in the proportion shown in Table 4. These lenses were evaluated and the results of evaluation are also shown in Table 4.
Testing Procedures
The testing procedures employed in the foregoing examples and comparative examples are described below. Test items other than surface accuracy and falling ball test were evaluated by using flat disks having a thickness of 2 mm or 5 mm and an external diameter of 75 mm.
Visible light transmittance (%): This was measured according to ASTM D1003-61.
Refractive index: Using the D line at 589.3 nm, this was measured with an Abbe refractometer.
Saturated water absorption (wt.%): A flat disk having a thickness of 5 mm was allowed to stand in a 100% saturated steam chamber at 70.degree. C. for 3 days. Thereafter, its weight gain was measured.
Falling ball test: A lens having a thickness of 1.5 mm was tested according to the FDA standards. Various steel balls were allowed to fall on the lens from a height of 127 cm, and the test result is expressed by the weight of the largest steel ball which did not crack the lens.
Rockwell hardness: This was measured according to JIS K7202.
Thermal resistance: Using a TMA measuring apparatus, Tg was measured under a load of 10 g.
Surface accuracy: The central part of a lens was examined for distortion with the naked eye and rated on the following basis.
A=No distortion was observed. (The difference between the design curvature and the curvature of the tested lens was 0-1%).
B=Slight distortion was observed. (The difference was 1-3%.)
C=Appreciable distortion was observed. (The difference was 3-5%.)
D=Moderate distortion was observed. (The difference was 5-10%.)
E=Marked distortion was observed. (The difference was 10-20%.)
F=The lens cannot be used. (The difference was greater than 20%.)
Casting workability: Each composition was examined for the ease of pouring into a mold.
O=Easy to pour.
X=Difficult to pour.
Dyeability: 2 g of a dye (commercially available under the trade name of Seiko Plax Diacoat from Hattori Seiko Co., Ltd.) was dispersed in 1 liter of water. Using this dispersion, a flat disk was dyed at 90.degree. C. for 5 minutes and its visible light transmittance was measured.
TABLE 1__________________________________________________________________________ Visible light Component Component Component Component trans- Refractive (A) (B) (C) (D) mittance index (g) (g) (g) (g) (%) at 20.degree. C.__________________________________________________________________________Example 1 9BGDM UDM1 TCDM HDDM 92 1.504 35 40 20 5Example 2 9BGDM UDM1 CHM HDDA 91 1.499 30 45 15 10Example 3 12BGDM UDM1 IBA HDDA 91 1.501 30 40 20 10Example 4 9BGDM UDM1 TCDM -- 92 1.503 50 30 20Example 5 9BGDM UDM2 TCDM -- 91 1.525 10 40 50Example 6 9BGDM UDM2 TCDM -- 91 1.520 30 50 20Example 7 9BGDM UDM2 TCDM -- 91 1.524 20 70 10Example 8 9BGDM UDA3 ADM -- 91 1.554 30 50 20Comparative -- -- -- DGBC 92 1.499Example 1 100Comparative 9BGDM -- TCDM HDDM 92 1.510Example 2 40 50 10Comparative 9BGDM UDM1 -- -- 90 1.501Example 3 10 90Comparative 9BGDM UDM1 -- HDDM 92 1.500Example 4 30 50 20Comparative -- UDM1 TCDM -- 92 1.512Example 5 50 50Comparative 9BGDM UDM1 TCDM -- 92 1.495Example 6 70 20 10Comparative -- UDM1 TCDM 9EGDM 35 92 1.505Example 7 40 20 HDDM 5Comparative 9BGDM UDM1 TCDM -- 92 1.507Example 8 10 20 70__________________________________________________________________________ Saturated Falling water ball Rockwell Thermal Casting absorption test hardness resistance Surface work- (%) (g) (M) (Tg) accuracy ability Dyeability__________________________________________________________________________Example 1 1.2 24 105 110 A .largecircle. 23Example 2 1.3 24 98 102 A .largecircle. 28Example 3 1.0 35 95 115 A .largecircle. 25Example 4 1.2 22 85 95 B .largecircle. 19Example 5 1.0 18 117 98 A .largecircle. 48Example 6 1.3 22 103 106 A .largecircle. 27Example 7 1.6 22 113 104 C .largecircle. 37Example 8 1.2 22 120 119 B .largecircle. 29Comparative 2.2 24 100 80 D .largecircle. 32Example 1Comparative 0.6 18 60 70 E .largecircle. 21Example 2Comparative 2.4 14 120 105 D X 68Example 3Comparative 2.0 14 98 114 F .largecircle. 30Example 4Comparative 1.0 9 121 105 C .largecircle. 89Example 5Comparative 1.2 45 40 45 D .largecircle. 12Example 6Comparative 3.6 14 104 105 B .largecircle. 20Example 7Comparative 0.7 9 110 96 D .largecircle. 61Example 8__________________________________________________________________________
TABLE 2__________________________________________________________________________ Visible light Component Component Component Component trans- Refractive (A) (B) (C) (D) mittance index (g) (g) (g) (g) (%) at 20.degree. C.__________________________________________________________________________Example 9 9BGDM UDM1 PhM HDDM 91 1.517 35 40 20 5Example 10 12BGDM UDM1 BPhM HDDA 90 1.522 30 40 20 10Example 11 9BGDM UDM2 BzM -- 91 1.529 30 50 20Example 12 9BGDM UDA3 3BrPM -- 90 1.565 30 50 20Comparative 9BGDM -- PhM HDDM 91 1.527Example 9 40 50 10Comparative -- UDM1 PhM -- 91 1.531Example 10 50 50Comparative -- UDM1 PhM 9EGDM 35 91 1.517Example 11 40 20 HDDM 5Comparative 9BGDM UDM1 PhM -- 90 1.545Example 12 10 20 70__________________________________________________________________________ Saturated Falling water ball Rockwell Thermal Casting absorption test hardness resistance Surface work- (%) (g) (M) (Tg) accuracy ability Dyeability__________________________________________________________________________Example 9 1.2 24 103 108 A .largecircle. 27Example 10 1.1 28 98 112 A .largecircle. 28Example 11 1.4 24 100 102 A .largecircle. 30Example 12 1.1 22 116 115 B .largecircle. 31Comparative 1.2 16 58 65 F .largecircle. 27Example 9Comparative 1.2 6 111 103 C .largecircle. 90Example 10Comparative 4.1 16 101 103 B .largecircle. 27Example 11Comparative 1.6 6 100 90 E .largecircle. 67Example 12__________________________________________________________________________
TABLE 3__________________________________________________________________________ Visible light Component Component Component Component trans- Refractive (A) (B) (C) (D) mittance index (g) (g) (g) (g) (%) at 20.degree. C.__________________________________________________________________________Example 13 9BGDM EDM1 TCDM HDDM 91 1.531 35 40 20 5Example 14 12BGDM EDM1 IBA HDDA 91 1.533 30 40 20 10Example 15 9BGDM EDA2 TCDM -- 91 1.548 10 40 50Example 16 9BGDM EDA2 TCDM -- 91 1.550 30 50 20Comparative 9BGDM EDM1 -- -- 90 1.553Example 13 10 90Comparative 9BGDM EDM1 -- HDDM 91 1.530Example 14 30 50 20Comparative -- EDM1 TCDM -- 91 1.542Example 15 50 50Comparative -- EDM1 TCDM 9EGDM 35 91 1.532Example 16 40 20 HDDM 5__________________________________________________________________________ Saturated Falling water ball Rockwell Thermal Casting absorption test hardness resistance Surface work- (%) (g) (M) (Tg) accuracy ability Dyeability__________________________________________________________________________Example 13 1.6 22 99 130 A .largecircle. 33Example 14 1.4 28 98 135 A .largecircle. 35Example 15 1.3 18 122 128 A .largecircle. 55Example 16 1.0 20 111 133 A .largecircle. 36Comparative 2.5 12 108 127 D X 74Example 13Comparative 2.4 18 105 136 F .largecircle. 42Example 14Comparative 2.0 9 120 130 C .largecircle. 83Example 15Comparative 3.9 18 104 135 B .largecircle. 29Example 16__________________________________________________________________________
TABLE 4__________________________________________________________________________ Visible light Component Component Component Component trans- Refractive (A) (B) (C) (D) mittance index (g) (g) (g) (g) (%) at 20.degree. C.__________________________________________________________________________Example 17 9BGDM EDM1 PhM HDDM 91 1.538 35 40 20 5Example 18 9BGDM EDM1 3BrPM HDDA 90 1.545 30 45 15 10Example 19 12BGDM EDM1 BPhM HDDA 90 1.547 30 40 20 10Example 20 9BGDM EDA2 HPM -- 90 1.562 10 40 50Example 21 9BGDM EDA2 POM -- 90 1.573 20 70 10Example 22 9BGDM EDM3 3BrPM -- 90 1.556 30 50 20Comparative -- EDM1 PhM -- 90 1.559Example 17 50 50Comparative -- EDM1 PhM 9EGDM 35 90 1.538Example 18 40 20 HDDM 5Comparative 9BGDM EDM1 PhM -- 90 1.552Example 19 10 20 70__________________________________________________________________________ Saturated Falling water ball Rockwell Thermal Casting absorption test hardness resistance Surface work- (%) (g) (M) (Tg) accuracy ability Dyeability__________________________________________________________________________Example 17 1.6 22 97 127 A .largecircle. 38Example 18 1.5 22 105 135 A .largecircle. 41Example 19 1.2 28 100 133 A .largecircle. 37Example 20 1.6 22 117 122 A .largecircle. 59Example 21 1.3 22 125 138 C .largecircle. 46Example 22 1.3 22 112 136 B .largecircle. 40Comparative 2.0 9 124 131 C .largecircle. 85Example 17Comparative 4.2 18 98 132 B .largecircle. 34Example 18Comparative 1.8 6 101 93 E .largecircle. 80Example 19__________________________________________________________________________

Number	Date	Country
2-27118	Feb 1990	JPX
2-36148	Feb 1990	JPX
2-176223	Jul 1990	JPX
2-176224	Jul 1990	JPX

Number	Name	Date
3876581	Neogi	Apr 1975
3988274	Masuhara et al.	Oct 1976
4618658	Hefner, Jr. et al.	Oct 1986

Number	Date	Country
0269366	Jan 1988	EPX
0430209	May 1991	EPX
0109073	May 1984	GBX

Composition for plastic lenses

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Entry
Patent Abstracts of Japan, vol. 11, No. 69(C-407) [2516], Mar. 3, 1987, & JP-A-61-228007, Oct. 11, 1986, M. Iwasaki, et al., "Photo-Polymerizable Composition".
Patent Abstracts of Japan, vol. 10, No. 172 (C-354) [2228], Jun. 18, 1986 & JP-A-61-021119, Jan. 29, 1986, S. Takeyama, et al., "Photosetting Resin Composition".