Material for plastic lens, production process of the material, composition for plastic lens, plastic lens obtained by curing the composition, and production process of the plastic lens

Abstract

A material for plastic lenses, comprising at least one group represented by the following formula (1) as a terminal group and a group represented by the following formula (2) as a repeating unit. 1

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is an application filed under 35 U.S.C. §111(a) claiming benefit pursuant to 35 U.S.C. §119(e)(1) of the filing date of the Provisional Application 60/218,802 filed Jul. 18, 2000, pursuant to 35 §111(b).

TECHNICAL FIELD

[0002] The present invention relates to a material for plastic lenses, a production process of the material, a plastic lens composition containing the material, a plastic lens obtained by curing the composition, and a production process of the plastic lens.

[0003] More specifically, the present invention relates to a plastic lens material which can be used for a plastic lens composition capable of preventing damage to a lens or a mold due to curing shrinkage arising as a problem during the polymerization of a polyethylene glycol poly(allyl carbonate)-based plastic lens material; a production process of the material; a plastic lens composition containing the material; a plastic lens obtained by curing the composition; and a production process of the plastic lens.

BACKGROUND ART

[0004] In recent years, organic glasses are widely used as optical materials in camera, television, prism, telescope and ophthalmic lenses. In particular, in the field of ophthalmic lenses, inorganic glasses are being overtaken by organic glasses, particularly in plastic lenses. Under these circumstances, the plastic lens is required to be more lightweight and easier to mold.

[0005] Representative examples of the resin conventionally used as a raw material for plastic lenses include polystyrene resin, polycarbonate resin, polymethyl methacrylate resin and polydiethylene glycol bis(allyl carbonate) resin. The physical properties and production methods of these resins have been long known and are described in detail, for example, in Plastic Age, Vol. 35, pp. 198-202 (1989).

[0006] In this publication, the properties of the plastic lenses derived from various resins are described as follows. The plastic lens derived from polystyrene resin has a problem in that a sufficiently high value cannot be obtained with respect to birefringence and light scattering, though the refractive index is high. The plastic lens derived from polycarbonate resin is disadvantageously inferior in resistance against a solvent or scratching, though the impact resistance is high. In the plastic lens derived from polymethyl methacrylate resin, the refractive index is low and the impact resistance is not at a satisfactory level.

[0007] Other than these, a plastic lens derived from polydiethylene glycol bis(allyl carbonate) resin is known (see, for example, European Patent Publication No. 0473163A). This plastic lens is favored with excellent properties particularly as a plastic lens for eyeglasses, such as superior impact resistance and high Abbe number, therefore, is most frequently used despite its low refractive index of 1.498.

[0008] The polydiethylene glycol bis(allyl carbonate) resin is also advantageous in that the polymerization reaction proceeds at a low speed as compared with acrylic resin, therefore, the polymerization reaction is easy to control and a uniform polymerization reaction can be attained and, as a result, the plastic lens derived from the polydiethylene glycol bis(allyl carbonate) resin is advantageously reduced in optical strain.

[0009] Furthermore, the plastic lens derived from polydiethylene glycol bis(allyl carbonate) resin is known to have dyeability such that when the lens is dyed according to a general technique of dipping a plastic lens obtained by cast-molding in a dye bath at a high temperature, the dyeing density is higher than those of plastic lenses derived from other resins.

[0010] In general, a plastic lens is manufactured by so-called cast polymerization where a monomer is polymerized using two glass molds. The molds must be cleaned after the cast-molding and the cleaning is usually performed using a strong alkaline solution or a strong acid. Unlike metal, glass is scarcely changed in quality by cleaning, therefore, glass is preferably used. Furthermore, glass can be easily polished and thereby extremely reduced in surface roughness.

[0011] The polymerization process generally incurs curing shrinkage. On the other hand, the lens must perfectly take after the curve on the glass surface and to this purpose, the monomer is required to exhibit good adhesion to the glass during the polymerization.

[0012] If the curing shrinkage in percentage is excessively large, cracks may be generated on the lens when the curing speed is increased, or the lens or the mold may be damaged at the release of lens from the mold. This phenomenon randomly occurs in the production of lenses. In the case of plastic lenses derived from polyethylene glycol bis(allyl carbonate) resin, the loss ascribable to this phenomenon usually reaches several % of the production of plastic lenses.

DISCLOSURE OF INVENTION

[0013] It is an object of the present invention to provide a compound useful as a plastic lens material capable of providing a cured product having a high Abbe number and a relatively small curing shrinkage, a production process of the compound, a plastic lens composition containing the compound, a plastic lens obtained by curing the composition, and a production process of the plastic lens.

[0014] As a result of extensive investigation to solve the above-described problems, the present inventors have found that by using a (meth)ally ester-based compound containing an alicyclic structure, a plastic lens material capable of providing a cured product having a high Abbe number and a relatively small curing shrinkage can be obtained. The present invention has been accomplished based on this finding.

[0015] More specifically, the present invention (I) is a material for plastic lenses, comprising at least one group represented by the following formula (1) as a terminal group and a group represented by the following formula (2) as a repeating unit: 2

[0016] wherein each R1 independently represents an allyl group or a methallyl group and each A1 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride. 3

[0017] wherein each A2 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride and each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule, provided that by the ester bonding, X can have a branched structure having a group of the above formula (1) as a terminal group and a group of the above formula (2) as a repeating unit.

[0018] The present invention (II) is a process for producing the material of the present invention (I), comprising a step of transesterifying at least one member selected from the group consisting of compounds represented by the following formula (3) with the polyhydric alcohol described above with respect to the present invention (I) in the presence of a catalyst to obtain a plastic lens material. 4

[0019] wherein A represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride, and R4 and R5 each independently represents an allyl group or a methallyl group.

[0020] The present invention (III) relates to a composition for plastic lenses, comprising at least one material of the present invention (I).

[0021] The present invention (IV) is a composition for plastic lenses, comprising from 0.1 to 10 parts by mass of at least one radical polymerization initiator and 100 parts by mass of the composition for plastic lenses of the present invention (III).

[0022] The present invention (V) is a plastic lens obtained by curing the composition for plastic lenses of the present invention (III) or the present invention (IV).

[0023] The present invention (VI) is a process for producing the plastic lens of the present invention (V).

BRIEF DESCRIPTION OF DRAWINGS

[0024] The figures attached hereto are a 400 MHz 1H-NMR spectrum chart and an FT-IR spectrum chart of each compound for plastic lens materials described in Examples.

[0025] FIG. 1 is a 400 MHz 1H-NMR spectrum chart of the allyl ester compound produced in Production Example 1.

[0026] FIG. 2 is a FT-IR spectrum chart of the allyl ester compound produced in Production Example 1.

[0027] FIG. 3 is a 400 MHz 1H-NMR spectrum chart of the allyl ester compound produced in Production Example 2.

[0028] FIG. 4 is an FT-IR spectrum chart of the allyl ester compound produced in Production Example 2.

[0029] FIG. 5 is a 400 MHz 1H-NMR spectrum chart of the allyl ester compound produced in Production Example 3.

[0030] FIG. 6 is an FT-IR spectrum chart of the allyl ester compound produced in Production Example 3.

[0031] FIG. 7 is a 400 MHz 1H-NMR spectrum chart of the allyl ester compound produced in Production Example 4.

[0032] FIG. 8 is an FT-IR spectrum chart of the allyl ester compound produced in Production Example 4.

BEST MODE FOR CARRYING OUT THE INVENTION

[0033] The present invention is described in detail below.

[0034] First, the material of the present invention (I) is described. The present invention (I) is a material for plastic lenses, comprising at least one group represented by the following formula (1) as a terminal group and a group represented by the following formula (2) as a repeating unit: 5

[0035] wherein each R1 independently represents an allyl group or a methallyl group and each A1 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride. 6

[0036] wherein each A2 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride and each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule, provided that, by the ester bonding, X can have a branched structure having a group of the above formula (1) as a terminal group and a group of the above formula (2) as a repeating unit.

[0037] In formula (1), each R1 independently represents an allyl group or a methallyl group. Also, in formula (1), each A1 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride. In formula (2), each A2 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride. Also, in formula (2), each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule.

[0038] The term “each R1 independently represents an allyl group or a methallyl group” as used herein means that the moiety represented by R1 of the terminal group represented by formula (1) in the material of the present invention (I) all may be occupied by an allyl group or a methallyl group or may be partially occupied by an allyl group with the remaining by a methallyl group.

[0039] A1 in Formula (1) and A2 in formula (2) each represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride.

[0040] Examples of the dicarboxylic acid or carboxylic anhydride include aliphatic dicarboxylic acids and anhydrides thereof, such as succinic acid and succinic anhydride, glutaric acid and glutaric anhydride, adipic acid, malonic acid and malonic anhydride, and 2-methylsuccinic acid and 2-methylsuccinic anhydride dicarboxylic acids having an alicyclic structure and anhydrides thereof, such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic anhydride, and 4-methylcyclohexane-1,2-dicarboxylic acid and 4-methylcyclohexane-1,2-dicarboxylic anhydride and aromatic dicarboxylic acids and anhydrides thereof, such as terephthalic acid, isophthalic acid, and phthalic acid and phthalic anhydride. Needles to say, the present invention is not limited to these specific examples.

[0041] Among those, in view of the fluidity of the compound, preferred are glutaric acid, succinic acid, adipic acid, 2-methylsuccinic acid and 1,3-cyclohexanedicarboxylic acid, and more preferred are glutaric acid, 2-methylsuccinic acid, adipic acid and succinic acid.

[0042] The term “each A1 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride” or “each A2 independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride” as used herein means that the moiety represented by A1 of the terminal group represented by formula (1) in the material of the present invention (I) and the moiety represented by A2 of the repeating unit represented by formula (2) in the material of the present invention (I) (hereinafter “A1” and “A2” are collectively referred to as “A”) each may be entirely occupied by organic residues derived from dicarboxylic acids or carboxylic anhydrides having the same structure, may be occupied by organic residues derived from dicarboxylic acids or carboxylic anhydrides having different structures, or may be partially occupied by organic residues derived from dicarboxylic acids having the same structure with the remaining by organic residues derived from dicarboxylic acids having different structures.

[0043] More specifically, in the following structural formula (4) which is one example of the material of the present invention (I), As in the number of k contained in the repeating structure are independent of each other. 7

[0044] wherein each A independently represents an organic residue derived from a dicarboxylic acid, k represents an integer of 2 to 3, and X represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule.

[0045] In structural formula (4), the As, in the number k, all may be organic residues derived from dicarboxylic acids having different structures (that is, organic residues are derived one by one from dicarboxylic acids having k kinds of structure) or all may be organic residues derived from dicarboxylic acid having the same structure (that is, organic residues in the number of k are derived from dicarboxylic acids having one kind of structure). A mixed structure where some of As, in the number k, are organic residues derived from dicarboxylic acids having the same structure and some others are organic residues derived from dicarboxylic acids having different kinds of structure may also be used.

[0046] The term “each X independently represents” as used herein means that in the following structural formula (5) as one example of the repeating unit represented by formula (2), the Xs, in the number m, contained in the repeating structure are independent of each other. 8

[0047] wherein each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule, m represents 0 or an integer of 1 or more, and when m is an integer of 1 or more, n represents 0 or an integer of 1 or more and each A independently represents an organic residue derived from a dicarboxylic acid.

[0048] For example, in structural formula (5), the Xs, in the number m, all may be organic residues derived from different polyhydric alcohols (that is, organic residues are derived one by one from m kinds of polyhydric alcohol) or all may be organic residues derived from the same kind of polyhydric alcohol (that is, organic residues in the number of m are derived from one kind of polyhydric alcohol). A mixed structure where some of the Xs, in the number m, are organic residues derived from the same kind of polyhydric alcohol and some others are organic residues derived from different kinds of polyhydric alcohol may also be used. Moreover, in this mixed structure, all may be completely random or a part may be repeated.

[0049] By the ester bonding, X can have a branched structure containing the formula (1) as a terminal group and the formula (2) as a repeating unit. More specifically, for example, when an organic residue derived from cyclohexane-1,2,4-trimethanol, which is one example of the trihydric saturated alcohol, is present in X, the material of the present invention (I) can have a partial structure represented by the following structural formula (6). 9

[0050] Each X is of course independently an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule. Also, each A is independently an organic residue derived from a dicarboxylic acid.

[0051] In formula (2), each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule. Examples of the polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule include the following compounds. Needless to say, however, the present invention is not limited to these specific examples. 10

[0052] A dihydric alcohol represented by the following formula (14) may also be used. 11

[0053] wherein each R2 independently represents at least one member selected from the organic groups represented by the following structural formulae (15) to (17), each R3 independently represents at least one member selected from the organic residues represented by the following structural formulae (18) to (20), a and b each independently represents 0 or an integer of 1 to 10, and Y represents an organic group selected from the following structural formulae (21) and (22). 12

[0054] In formula (14), the term “each R2 independently represents at least one member selected from the organic groups” means that R2s in the number of a all may be organic groups having the same structure, all may be organic groups having different structures, or may be partially organic groups having the same structure with the remaining being organic groups having different structures, where, however, R2 must be selected from the organic groups represented by structural formulae (15) to (17).

[0055] In formula (14), the term “each R3 independently represents at least one member selected from the organic residues” means that R3s in the number of b all may be organic groups having the same structure, all may be organic groups having different structures or may be partially organic groups having the same structure with the remaining being organic groups having different structures, where, however, R3 must be selected from the organic groups represented by structural formulae (18) to (20).

[0056] In formula (14), a and b each independently represents 0 or an integer of 1 to 10. Y represents an organic group selected from the following structural formulae (21) and (22).

[0057] Specific examples of the dihydric alcohol represented by formula (14) include 2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane, 2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane, 3 mol ethylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane, 4 mol propylene oxide adducts of (4-hydroxycyclohexyl)propane, bis[4-(2-hydroxyethoxy)cyclohexyl]methane, bis[4-(2-hydroxypropoxy)cyclohexyl]methane, 3 mol ethylene oxide adducts of bis(4-hydroxycyclohexyl)methane, and 4 mol propylene oxide adducts of bis(4-hydroxycyclohexyl)methane. Needless to say, however, the present invention is not limited to these specific examples.

[0058] Among these polyhydric alcohols, since raw materials are easily available, the compounds of structural formula (7), structural formula (8) and structural formula (9), and 2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane, 2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane and 3 mol ethylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane are preferred, and the compound of structural formula (7), 2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane, 2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane and 3 mol ethylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane are more preferred.

[0059] The repeating number of the group represented by formula (2) which is a repeating unit of the material of the present invention (I) is not particularly limited. A mixture of materials having various repeating numbers may also be used. Furthermore, a material where the repeating number is 0 and a material where the repeating number is an integer of 1 or more may be used in combination. However, use of only a compound where the repeating number is 0 is disadvantageous in achieving the object of the present invention.

[0060] Usually, the repeating number of the group represented by formula (2) as a repeating unit of the material of the present invention (I) is preferably an integer of from 0 to 50. If a plastic lens material comprising only compounds where the repeating number exceeds 50 is used for a plastic lens composition, the allyl group concentration decreases and this may cause adverse effects, for example, at the time of curing, the curing may be retarded or a part of the compound may remain uncured to reduce the physical properties of the cured product such as mechanical properties. In all compounds contained in the plastic lens material, the repeating number is preferably an integer of 0 to 50, more preferably from 0 to 30, still more preferably from 0 to 10.

[0061] Depending of the production conditions, the compound represented by formula (3) as a raw material may remain in the material of the present invention (I) but the material may be used as it is as a plastic lens material. However, when the present invention (I) is used as a plastic lens material, it is disadvantageous for reducing the curing shrinkage in percentage that the compound represented by formula (3) is present in a proportion of 90% by mass or more based on the entire curable component.

[0062] Incidentally, the term “entire curable component” as used in the present invention means the total amount of the material of the present invention (I) and a monomer copolymerizable with at least one material of the present (I).

[0063] The present invention (II) is described below. The present invention (II) is a process for producing the material of the present invention (I), comprising a step of transesterifying at least one member selected from the group consisting of compounds represented by formula (3) with a polyhydric alcohol in the presence of a catalyst to obtain a compound for the plastic lens material.

[0064] In formula (3), R4 and R5 each independently represents an allyl group or a methallyl group.

[0065] Furthermore, in formula (3), A represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride. The dicarboxylic acid and carboxylic anhydride include aliphatic dicarboxylic acids and anhydrides thereof, such as succinic acid and succinic anhydride, glutaric acid and glutaric anhydride, adipic acid, malonic acid and malonic anhydride, and 2-methylsuccinic acid and 2-methylsuccinic anhydride; dicarboxylic acids having an alicyclic structure and anhydrides thereof, such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic anhydride, and 4-methylcyclohexane-1,2-dicarboxylic acid and 4-methylcyclohexane-1,2-dicarboxylic anhydride; and aromatic dicarboxylic acids and anhydrides thereof, such as terephthalic acid, isophthalic acid, and phthalic acid and phthalic anhydride. Needles to say, however, the present invention is not limited to these specific examples.

[0066] The compound of the material of the present invention (I) can be produced, for example, by the following process.

[0067] The objective compound can be obtained using at least one compound represented by formula (3) in a constant ratio through a step of transesterifying these compounds with at least one polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule in the presence of a catalyst. Of course, the present invention is not limited thereto and a step such as purification may be included, if desired.

[0068] The catalyst for use in the above-described step is not particularly limited as long as it is a catalyst capable of being used for transesterification in general. An organic metal compound is particularly preferred and specific examples thereof include tetraisopropoxy titanium, tetrabutoxy titanium, dibutyltin oxide, dioctyltin oxide, hafnium acetylacetonate and zirconium acetylacetonate, however, the present invention is not limited thereto. Among these, dibutyltin oxide and dioctyltin oxide are preferred.

[0069] The reaction temperature in this step is not particularly limited but is preferably from 100 to 230° C., more preferably 120 to 200° C. In the case where a solvent is used, the reaction temperature is sometimes limited by the boiling point of the solvent.

[0070] In this step, a solvent is usually not used, however a solvent may be used, if desired. The solvent which can be used is not particularly limited as long as it does not inhibit the transesterification. Specific examples thereof include benzene, toluene, xylene and cyclohexane, however, the present invention is not limited thereto. Among these, benzene and toluene are preferred. However, as described above, the step may be performed without using a solvent.

[0071] The composition for plastic lenses of the present invention (III) or the present invention (IV) is described below.

[0072] The present invention (III) is a composition for plastic lenses, comprising at least one compound of the material of the present invention (I).

[0073] The amount of the compound of the material of the present invention (I) blended is preferably from 5 to 80% by mass, more preferably from 15 to 70% by mass, based on the entire curable component contained in the composition for plastic lenses of the present invention (III). If the amount of the material blended is less than 5% by mass, the two requirements of high Abbe number and low curing shrinkage can seldom be satisfied at the same time and this is not preferred.

[0074] For the purpose, mainly, of adjusting the viscosity of the composition, one or more compounds copolymerizable with the compound of the material of the present invention (I) may be added to the present invention (III).

[0075] Examples of the compound include monomers having an acryl group, a vinyl group or an allyl group. Specific examples of the monomer having an acryl group include methyl (meth)acrylate and isobornyl (meth)acrylate, and specific examples of the monomer having a vinyl group include vinyl acetate and vinyl benzoate, and specific examples of the monomer having an allyl group include the compounds having a structural formulae (23) to (29) shown below. In addition, polyethylene glycol bis(allyl carbonate) resin represented by CR-39 (trade name, produced by PPG) may also be used. Of course, the present invention is not limited to these specific examples and diallyl phthalate, diallyl terephthalate, diallyl isophthalate, allyl benzoate and the like may also be used within the range of not impairing the physical properties of the plastic lens obtained by curing.

[0076] Specific examples of the compound which is preferably used include the compounds represented by the following structural formulae (23) to (29) and polyethylene glycol bis(allyl carbonate) resin. 13

[0077] The amount of the compound added greatly varies depending on the monomer used, however, the amount added is usually 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less, based on the entire curable component contained in the plastic lens composition of the present invention. If the compound is added in excess of 90% by mass, the two requirements for the plastic lens of the present invention, namely, high Abbe number and low curing shrinkage, are difficult to attain at the same time and this is not preferred.

[0078] With respect to other effects, when the plastic lens material of the present invention is added in an amount of 0.5% by mass or more to polyethylene glycol bis(allyl carbonate) resin, the uneven dyeing which appears at the dyeing of polyethylene glycol bis(allyl carbonate) resin can be reduced.

[0079] An optimal monomer is selected by taking account of the kinds and the mixing ratios of the above-described compound and the allyl ester oligomer contained in the resin composition for plastic lenses and the physical property values such as optical property required for the plastic lens obtained by curing the composition.

[0080] On taking account of operability in the casting, the viscosity of the plastic lens composition of the present invention (III) is generally 3,000 mPa.s or less at 25° C., preferably 1,000 mPa.s or less, more preferably 500 mPa.s or less.

[0081] The term “viscosity” as used herein is a viscosity measured by a rotational viscometer. The rotational viscometer is described in detail in Iwanami Rikagaku Jiten (Iwanami Physics and Chemistry Encyclopedia), 3rd ed., 8th imp. (Jun. 1, 1977).

[0082] The present invention (IV) is a composition for plastic lenses, comprising from 0.1 to 10 parts by mass of at least one radical polymerization initiator per 100 parts by mass of the composition for plastic lenses of the present invention (III).

[0083] The plastic lens composition of the present invention (IV) may contain a radical polymerization initiator as a curing agent and this is preferred.

[0084] The radical polymerization initiator which can be added to the plastic lens composition of the present invention (IV) is not particularly limited and a known radical polymerization initiator may be added as long as it does not adversely affect the physical property values such as optical property of the plastic lens obtained by curing the composition.

[0085] The radical polymerization initiator for use in the present invention is, however, preferably a radical polymerization initiator which is soluble in other components present in the composition to be cured and which generates free radicals at 30 to 120° C. Specific examples of the radical polymerization initiator which can be added include diisopropylperoxy dicarbonate, dicyclohexylperoxy dicarbonate, di-n-propylperoxy dicarbonate, di-sec-butylperoxy dicarbonate and tert-butyl perbenzoate, but the present invention is not limited thereto. In view of the curability, diisopropylperoxy dicarbonate is preferred.

[0086] The amount of the radical polymerization initiator added is in the range from 0.1 to 10 parts by mass, preferably from 1 to 5 parts by mass, per 100 parts by mass of the entire curable component contained in the plastic lens composition of the present invention (III). If the amount added is less than 0.1 part by mass, curing of the composition may proceed insufficiently, whereas if it exceeds 10 parts by mass, the profitability decreases and this is not preferred.

[0087] The plastic lens composition of the present invention (III) or the present invention (IV) may contain additives commonly used for the purpose of improving the performance of the plastic lens, such as a coloring agent including dye and pigment, an ultraviolet absorbent, a mold-releasing agent and an antioxidant.

[0088] Examples of the coloring agent include organic pigments such as anthraquinone type, azo type, carbonium type, quinoline type, quinoneimine type, indigoid type and phthalocyanine type; organic dyes such as azoic dye and sulfur dye; and inorganic pigments such as titanium yellow, yellow iron oxide, zinc yellow, chrome orange, molybdenum red, cobalt violet, cobalt blue, cobalt green, chromic oxide, titanium oxide, zinc sulfide and carbon black.

[0089] Examples of the mold-releasing agent include stearic acid, butyl stearate, zinc stearate, stearic acid amide, fluorine-containing compounds and silicone compounds.

[0090] Examples of the ultraviolet absorbent include triazoles such as 2-(2′-hydroxy-tert-butylphenyl)benzotriazole, benzophenones such as 2,4-dihydroxybenzophenone, salicylates such as 4-tert-butylphenyl salicylate, and hindered amines such as bis-(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0091] Examples of the antioxidant include phenols such as 2,6-di-tert-butyl-4-methylphenol and tetrakis[methylene-3-(3′,5′-di-tert-butyl-4-hydroxyphenyl)propionate]methane; sulfurs such as dilauryl-3,3′-thiodipropionate; and phosphorus-containing antioxidants such as trisnonylphenylphosphite.

[0092] The total amount of the additives added, such as a coloring agent including dye and pigment, an ultraviolet absorbent, a mold-releasing agent and an antioxidant, is preferably 1% by mass or less based on the entire curable resin component contained in the resin composition for plastic lenses of the present invention.

[0093] The present invention (V) is described below. The present invention (V) is a plastic lens obtained by curing the plastic lens composition of the present invention (III) or the present invention (IV).

[0094] The curing shrinkage in percentage of the plastic lens in the present invention is preferably 10.0% or less at 23° C. The reason therefor is that if the curing shrinkage in percentage on curing is excessively large, cracks are readily generated during the curing and, as a result, the yield at the molding decreases.

[0095] Finally, the present invention (VI) is described. The present invention (VI) is a process for producing the plastic lens of the present invention (V), comprising curing the plastic lens composition of the present invention (III) or the present invention (IV).

[0096] In the present invention, the mold-working of the plastic lens composition is suitably performed by cast-molding. Specifically, a method of adding a radical polymerization initiator to the composition, injecting the mixture through a line into a mold fixed by an elastomer gasket or a spacer, and curing it under heating in an oven may be used.

[0097] The constructive material of the mold used here is a metal or glass. In general, the mold for plastic lenses must be cleaned after the cast-molding and such cleaning is usually performed using a strong alkali solution or a strong acid. Unlike metal, glass is scarcely changed in the quality by the cleaning and furthermore, glass can be easily polished and thereby extremely reduced in the surface roughness, therefore, glass is preferably used.

[0098] The plastic lens composition of the present invention (III) or the present invention (IV) has an alicyclic structure, accordingly, depending on the molecular design, the refractive index can be easily approximated to the refractive index 1.498 of the plastic lens starting from polydiethylene glycol bis(allyl carbonate) which is used for plastic lenses in many cases. This is advantageous in that the mold or the like conventionally used in the molding need not be changed but can be used as it is.

[0099] The curing temperature at the molding is from about 30 to 120° C., preferably from 40 to 100° C. With respect to the operation of curing temperature, on taking account of shrinkage or strain at the curing, a method of allowing the curing to gradually proceed while elevating the temperature is preferably used. The curing time is generally from 0.5 to 100 hours, preferably from 3 to 50 hours, more preferably from 10 to 30 hours.

[0100] The method for dyeing the plastic lens of the present invention is not particularly limited. Any method may be used as long as it is a known dyeing method for plastic lenses. Among these, a dip dyeing method conventionally known as a general method is preferred. The “dip dyeing method” as used herein means a method of dispersing a disperse dye together with a surfactant in water to prepare a dye bath and dipping a plastic lens in this dyeing solution under heating, thereby dyeing the plastic lens.

[0101] The method for dyeing the plastic lens is not limited to this dip dyeing method but other known methods may be used, for example, a method of sublimating an organic pigment and thereby dyeing a plastic lens (see, Japanese Examined Patent Publication No. 35-1384, JP-B-35-1384) or a method of sublimating a sublimable dye and thereby dyeing a plastic lens (see, Japanese Examined Patent Publication Nos. 56-159376 and 1-277814, JP-B-56-159376 and JP-B-1-277814) may be used. In view of simple operation, the dip dyeing method is most preferred.

[0102] The present invention is further illustrated below by referring to the following examples, however, the present invention should not be construed as being limited thereto.

[0103] Various physical properties were measured as follows.

[0104] 1. Refractive Index (nD) and Abbe Number (νD)

[0105] A test piece of 9 mm×16 mm×4 mm was prepared and measured on the refractive index (nD) and Abbe number (νD) at 25° C. using “Abbe Refractometer 1T” manufactured by Atago. The contact solvent used was α-bromonaphthalene.

[0106] 2. Viscosity

[0107] In Example 1, Examples 3 to 6, Examples 8 to 15, and Comparative Examples 1 to 5, 300 g of the specimen was charged into a 300-ml tall beaker. The viscosity of them was measured at 25° C. and at 20 rpm using No. 1 rotor by B-Type Viscometer (Model BH) manufactured by Tokyo Keiki Co., Ltd.

[0108] In Example 2 and Example 7, 5.2 ml of the specimen was charged into a designated sample adapter. The viscosity of them was measured at 25° C. at 100 rpm using an HH-1 rotor by B-Type Viscometer (Model B8U) manufactured by Tokyo Keiki Co., Ltd.

[0109] 3. Barcol Hardness

[0110] The Barcol hardness was measured using Model 934-1 according to JIS K 6911.

[0111] 4. Measurement of Curing Shrinkage in Percentage

[0112] The value of curing shrinkage in percentage (%) was calculated using the following formula from the specific gravity of the composition before curing and the specific gravity of the cured product.

[0113] Curing Shinkage in Percentage (%)=(1−(specific gravity of composition before curing/specific gravity of cured product))×100

[0114] At this time, the specific gravity of the composition before curing was measured by a specific gravity bottle at a measuring temperature of 23° C. according to the measuring method for specific gravity (see, JIS Z 8804). The specific gravity after curing was measured by a sink-float method (at 23° C.) (see, JIS K 7112).

[0115] 5. Dyeing Method and Evaluation of Uneven Dyeing

[0116] To a 1 l beaker, 0.8 g of Sumikaron Blue E-FBL (produced by Sumitomo Chemical Co., Ltd.) and 0.5 L of water were added and dissolved with stirring. The resulting solution was heated in a water bath at 80° C. and into this disperse dye solution, cured plastic lens samples each fixed to a holder so as not to overlap one on another were dipped at 80° C. for 10 minutes. Thereafter, the samples were taken out, thoroughly washed with water and then hot-air dried in an oven at 30° C.

[0117] The thus-obtained dyed plastic lens samples were observed with an eye and those failed in having a uniformly dyed appearance and revealed to have uneven dyeing were rated “defective”. By evaluating 30 cured samples in total, the number of “defective” samples was counted.

PRODUCTION EXAMPLE 1

[0118] Into a 500 ml three-neck flask with a distillation unit, 160.2 g of dimethyl glutarate, 232.3 g of allyl alcohol, 0.27 g of potassium acetate and 1.33 g (1% by mass based on dimethyl glutarate) of calcium hydroxide were charged. The system was heated at a bath temperature of 110 to 120° C. in a nitrogen stream, and methanol generated was distilled off. The reaction was continued until a theoretical amount of methanol was distilled off, and when 64 g (100% based on the theoretical distillation amount of methanol) was distilled off, the reactor was cooled. The resulting reaction solution was purified by distillation under reduced pressure, as a result, 200 g of diallyl glutarate was obtained as a colorless transparent liquid (isolation yield: 95%, raw material: 1 mol).

[0119] Into a 300 ml three-neck flask with a distillation unit, 101 g (0.48 mol) of diallyl glutarate, 53.8 g (0.373 mol) of 1,4-cyclohexane dimethanol and 0.1 g (1% by mass based on diallyl glutarate) of dibutyltin oxide were charged. The system was heated at 180° C. in a nitrogen stream, and the allyl alcohol generated was distilled off. When about 26 g of allyl alcohol was distilled off, the pressure within the reaction system was reduced to 1.33 kPa to increase the distillation rate of allyl alcohol. After a theoretical amount (43.6 g) of allyl alcohol was distilled off, the system was heated for another one hour and then kept at 190° C. and 0.13 kPa for one hour. Thereafter, the reactor was cooled, as a result, 110 g of an allyl ester compound was obtained (hereinafter referred to as “Sample A”). FIG. 1 and FIG. 2 show 400 MHz 1H-NMR spectrum (solvent: CDCl3) and FT-IR spectrum of Sample A, respectively.

[0120] In FIG. 1, the peak in the vicinity of 0.9 to 2.0 ppm is attributable to a proton derived from cyclohexane ring, the peak in the vicinity of 2.3 to 2.5 ppm is attributable to a proton derived from glutaric acid skeleton, the peak in the vicinity of 3.7 to 4.1 ppm is attributable to a proton of methylene derived from cyclohexanedimethanol which is ester-bonded, the peak in the vicinity of 4.6 ppm is attributable to a proton of methylene at the allyl position, the peak in the vicinity of 5.3 ppm is attributable to a proton in the terminal of the double bond at the allyl position, and the peak in the vicinity of 5.8 ppm is attributable to a proton in the inner side of the double bond at the allyl position.

[0121] In FIG. 2, the peak at 1738 cm−1 is absorption by the carbonyl stretching vibration of the carboxyl group.

[0122] Sample A was analyzed by gas chromatography (GC-14B manufactured by Shimadzu Corp., hydrogen flame ionization detector, column used: OV-17 of 0.5 m, the temperature condition: 160° C. and constant) and found to contain 3.88% by mass of diallyl glutarate.

PRODUCTION EXAMPLE 2

[0123] Into a 3 l three-neck flask with a distillation unit, 660.6 g of succinic anhydride, 1,056 g of allyl alcohol, 1,000 ml of benzene and 6.61 g (1% by mass based on succinic anhydride) of concentrated sulfuric acid were charged. The system was heated at 100° C. in a nitrogen stream, and H2O generated was distilled off. The reaction was continued until a theoretical amount of H2O was distilled off and when 109 g (100% based on the theoretical distillation amount of H2O) of H2O was distilled off, the reactor was cooled. The resulting reaction solution was neutralized with an aqueous NaOH solution and washed with water. After benzene and excess allyl alcohol were distilled off, the reaction solution was purified by distillation under reduced pressure, as a result, 1,130 g of diallyl succinate was obtained as a colorless transparent liquid.

[0124] Into a 3 l three-neck flask with a distillation unit, 1,784 g of diallyl succinate, 829 g of 1,4-cyclohexanedimethanol and 1.784 g (1% by mass based on diallyl succinate) of dibutyltin oxide were charged. The system was heated at 180° C. in a nitrogen stream and the allyl alcohol generated was distilled off. When about 418 g of allyl alcohol was distilled off, the pressure within the reaction system was reduced to 1.33 kPa to increase the distillation rate of allyl alcohol. After a theoretical amount (618 g) of allyl alcohol was distilled off, the system was heated for another one hour and then kept at 190° C. and 0.13 kPa for one hour. Thereafter, the reactor was cooled, as a result, 1,897 g of an allyl ester compound was obtained (hereinafter referred to as “Sample B”). FIG. 3 and FIG. 4 show 400 MHz 1H-NMR spectrum (solvent: CDCl3) and FT-IR spectrum of Sample B, respectively.

[0125] In FIG. 3, the peak in the vicinity 0.9 to 2.0 ppm is attributable to a proton derived from a cyclohexane ring, the peak in the vicinity 2.6 to 2.7 ppm is attributable to a proton derived from a succinic acid skeleton, the peak in the vicinity 3.9 to 4.2 ppm is attributable to a proton of methylene derived from cyclohexanedimethanol which is ester-bonded, the peak in the vicinity 4.5 ppm is attributable to a proton of methylene at the allyl position, the peak in the vicinity 5.3 ppm is attributable to a proton in the terminal of the double bond at the allyl position, and the peak in the vicinity 5.9 ppm is attributable to a proton in the inner side of the double bond at the allyl position.

[0126] In FIG. 4, the peak of 1736 cm−1 is absorption by the carbonyl stretching vibration of the carboxyl group.

[0127] Sample B was analyzed by gas chromatography (GC-14B: manufactured by Shimadzu Corp., hydrogen flame ionization detector, column used: OV-17 of 0.5 m, temperature condition: 160° C. and constant) and found to contain 11.8% by mass of diallyl succinate.

PRODUCTION EXAMPLE 3

[0128] Into a 1 l three-neck flask with a distillation unit, 1,000 g of dimethyl 2-methylsuccinate, 1,441 g of allyl alcohol, 25 g of potassium acetate and 5 g of calcium hydroxide were charged. The system was heated at 110° C. in a nitrogen stream, and methanol generated was distilled off. The reaction was continued until a theoretical amount of methanol was distilled off and when 385.7 g (97%) was distilled off, the reactor was cooled. The resulting reaction solution was filtered by suction using a No. 5C Kiriyama funnel to separate the solid matters in the reaction solution. Thereafter, the solution was purified by distillation under reduced pressure, as a result, 1,200 g of diallyl 2-methylsuccinate was obtained as a colorless transparent liquid.

[0129] Into a 1 l three-neck flask with a distillation unit, 640 g of diallyl 2-methylsuccinate, 336 g of 1,4-cyclohexanedimethanol and 0.639 g of dibutyltin oxide were charged. The system was heated at 180° C. in a nitrogen stream and allyl alcohol generated was distilled off. When about 190 g of allyl alcohol was distilled off, the pressure within the reaction system was reduced to 1.33 kPa to increase the distillation rate of allyl alcohol. After a theoretical amount (270.7 g) of allyl alcohol was distilled off, the system was heated for another one hour and then kept at 190° C. and 0.13 kPa for one hour. Thereafter, the reactor was cooled and, as a result, 705 g of an allyl ester compound was obtained (hereinafter referred to as “Sample C”). FIG. 5 and FIG. 6 show 400 MHz 1H-NMR spectrum (solvent: CDCl3) and FT-IR spectrum of Sample C, respectively.

[0130] In FIG. 5, the peak in the vicinity of 0.9 to 2.0 ppm is attributable to a proton derived from a cyclohexane ring, with the peak in the vicinity of 1.2 ppm being a peak derived from the branched methyl group in succinic acid, the peak in the vicinity of 2.4 to 3.0 ppm is attributable to a proton derived from 2-methylsuccinic acid skeleton, the peak in the vicinity of 3.9 to 4.2 ppm is attributable to a proton of methylene derived from cyclohexanedimethanol which is ester-bonded, the peak in the vicinity of 4.6 ppm is attributable to a proton of methylene at the allyl position, the peak in the vicinity of 5.3 ppm is attributable to a proton in the terminal of the double bond at the allyl position, and the peak in the vicinity of 5.8 to 6.0 ppm is attributable to a proton in the inner side of the double bond at the allyl position.

[0131] In FIG. 6, the peak of 1738 cm−1 is absorption by the carbonyl stretching vibration of the carboxyl group.

[0132] Sample C was analyzed by gas chromatography (GC-14B: manufactured by Shimadzu Corp., hydrogen flame ionization detector, column used: OV-17 of 0.5 m, temperature condition: 160° C. and constant) and found to contain 3.8% by mass of diallyl 2-methylsuccinate.

PRODUCTION EXAMPLE 4

[0133] Into a 3 l three-neck flask with a distillation unit, 660.6 g of succinic anhydride, 1,056 g of allyl alcohol, 1,000 ml of benzene and 6.61 g (1% by mass based on succinic anhydride) of concentrated sulfuric acid were charged. The system was heated at 100° C. in a nitrogen stream and H2O generated was distilled off. The reaction was continued until a theoretical amount of H2O was distilled off and when 109 g (100% based on the theoretical distillation amount of H2O) of H2O was distilled off, the reactor was cooled. The resulting reaction solution was neutralized with an aqueous NaOH solution and washed with water. After benzene and excess allyl alcohol were distilled off, the reaction solution was purified by distillation under reduced pressure and, as a result, 1,130 g of diallyl succinate was obtained as a colorless transparent liquid.

[0134] Into a 1 l three-neck flask with a distillation unit, 396.4 g of diallyl succinate, 328.5 g of 2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane (HBA-2, trade name, produced by Nippon Nyukazai K.K.) and 0.4 g of dibutyltin oxide were charged. The system was heated at 180° C. in a nitrogen stream and the allyl alcohol generated was distilled off. When about 81.3 g of allyl alcohol was distilled off, the pressure within the reaction system was reduced to 1.33 kPa to increase the distillation rate of allyl alcohol. After a theoretical amount (116.2 g) of allyl alcohol was distilled off, the system was heated for another one hour and then kept at 190° C. and 0.13 kPa for one hour. Thereafter, the reactor was cooled and, as a result, 256 g of an allyl ester compound was obtained (hereinafter referred to as “Sample D”). FIG. 7 and FIG. 8 show 400 MHz 1H-NMR spectrum (solvent: CDCl3) and FT-IR spectrum of Sample D, respectively.

[0135] In FIG. 7, the peak in the vicinity 0.6 to 0.8 ppm is attributable to a proton derived from a propane skeleton, the peak in the vicinity 0.9 to 2.2 ppm is attributable to a proton derived from a cyclohexane ring, the peak in the vicinity 2.6 ppm is attributable to a proton derived from a succinic acid skeleton, the peak in the vicinity 3.6 is attributable to a proton of methylene derived from cyclohexanedimethanol which is ester-bonded, the peak in the vicinity 4.6 ppm is attributable to a proton of methylene at the allyl position, the peak in the vicinity 5.3 ppm is attributable to a proton in the terminal of the double bond at the allyl position, and the peak in the vicinity 5.8 to 6.0 ppm is attributable to a proton in the inner side of the double bond at the allyl position.

[0136] In FIG. 8, the peak of 1737 cm−1 is absorption by the carbonyl stretching vibration of the carboxyl group.

[0137] Sample D was analyzed by gas chromatography (GC-14B: manufactured by Shimadzu Corp., hydrogen flame ionization detector, column used: OV-17 of 0.5 m, temperature condition: 160° C. and constant) and found to contain 12.3% by mass of diallyl succinate.

[0138] In the following examples, Samples A to D were diluted so as to decrease the viscosity, using the compound of the following structural formula (23) or the following structural formula (28). 14

[0139] The kind and composition of each diluted compound are shown in Table 1.

EXAMPLE 1

Production of Composition for Plastic Lens

[0140] As shown in Table 1, 40.0 parts by mass of the allyl ester compound as Sample A, 60.0 parts by mass of the compound represented by structural formula (24) and 3 parts by mass of diisopropylperoxy dicarbonate (IPP) were blended and mixed with stirring to form a completely homogeneous solution composition. The viscosity at this time was measured. Thereafter, a vessel containing this solution was placed in a desiccator capable of depressurization and the pressure was reduced by a vacuum pump for about 15 minutes to deaerate gases in the solution. The resulting solution composition was injected by a syringe into a mold fabricated from a glass-made mold for ophthalmic plastic lenses and a resin-made gasket, while taking care to prevent intermixing of gas, and then cured in an oven, according to a temperature rising program, under heating at 40° C. for 7 hours, heating at from 40 to 60° C. for 10 hours, heating at from 60 to 80° C. for 3 hours, heating at 80° C. for 1 hour and heating at 85° C. for 2 hours.

[0141] The lens obtained was measured on the refractive index, Abbe number, Barcol hardness and curing shrinkage in percentage. The results are shown in Table 1.

	TABLE 1
						Comparative	Comparative
	Example 1	Example 2	Example 3	Example 4	Example 5	Example 1	Example 2
Blending	Compound of structural		60.0					100
(parts by	formula (23)
mass)	Compound of structural	60.0		60.0	30.0	40.0
	formula (28)
	Sample A	40.0
	Sample B		40.0
	Sample C			40.0
	Sample D				70.0	60.0
	CR-39						100
Viscosity (25°) (mPa · s)	144	2160	200	180	136	25	10
Initiator IPP (parts by mass)	3	3	3	3	3	3	3
Physical	Refractive index (nD)	1.525	1.516	1.525	1.518	1.521	1.503	1.517
properties	Abbe number	53.3	59.7	53.6	57.7	54.9	51.6	56.1
of cured	Barcol hardness	25	30	30	13	22	29	47
product	Specific gravity	1.210	1.198	1.210	1.189	1.194	1.316	1.188
	Curing shrinkage in	7.4	9.0	7.3	6.1	6.2	12.8	11.6
	percentage

EXAMPLES 2 TO 5 AND COMPARATIVE EXAMPLES 1 AND 2

Production of Composition for Plastic Lenses

[0142] Compositions were prepared by the blending shown in Table 1 and measured on the viscosity and after the curing, on the refractive index, Abbe number, Barcol hardness and curing shrinkage in percentage, in the same manner as in Example 1. The results are shown in Table 1.

EXAMPLES 6 TO 10 AND COMPARATIVE EXAMPLES 3 AND 4

Production of Plastic Lens

[0143] A vessel containing a solution having each composition shown in Table 1 (compositions of Examples 1 to 5 and Comparative Examples 1 and 2) was placed in a desiccator capable of depressurization and the pressure was reduced by a vacuum pump for about 15 minutes to deaerate gases in the solution. The resulting solution composition was injected by a syringe into a mold (thickness: 3 mm) fabricated from a glass-made mold for ophthalmic plastic lenses and a resin-made gasket, while taking care to prevent intermixing of gas, and then cured in an oven, according to a temperature rising program, under heating at 40° C. for 3 hours, heating at from 40 to 85° C. for 3 hours, and heating at 85° C. for 2 hours.

[0144] According to the method described above, whether the cured product was cracked or not at the curing was observed with an eye. The results are shown in Table 2.

	TABLE 2
					Example	Comparative	Comparative
	Example 6	Example 7	Example 8	Example 9	10	Example 3	Example 4
Blending	Compound of structural		60.0					100
(parts	formula (23)
by mass)	Compound of structural	60.0		60.0	30.0	40.0
	formula (28)
	Sample A	40.0
	Sample B		40.0
	Sample C			40.0
	Sample D				70.0	60.0
	CR-39						100
Viscosity (25°) (mpa · s)	144	2160	200	180	136	25	10
Initiator IPP (parts by mass)	3	3	3	3	3	3	3
Cracked or not at curing	None	None	None	None	None	Cracked	Cracked

EXAMPLE 11

Production of Plastic Lens

[0145] As shown in Table 3, 95.0 parts by mass of diethylene glycol bisallyl carbonate (CR-39, trade name, produced by PPG), 5.0 parts by mass of Sample A and 3 parts by mass of diisopropylperoxy dicarbonate (IPP) were blended and mixed with stirring to form a completely homogeneous solution composition. The viscosity at this time was measured. Thereafter, a vessel containing this solution was placed in a desiccator capable of depressurization and the pressure was reduced by a vacuum pump for about 15 minutes to deaerate gases in the solution. The resulting solution composition was injected by a syringe into a mold fabricated from a glass-made mold for ophthalmic plastic lenses and a resin-made gasket, while taking care to prevent intermixing of gas, and then cured in an oven, according to a temperature rising program, under heating at 40° C. for 7 hours, heating at from 40 to 60° C. for 10 hours, heating at from 60 to 80° C. for 3 hours, heating at 80° C. for 1 hour and heating at 85° C. for 2 hours.

[0146] The lens obtained was measured on the refractive index, Abbe number and Barcol hardness and evaluated on the dyeing speck. The results are shown in Table 3.

[0147] In Example 11, the viscosity (at 25° C.) of the compound before curing was less than 100 mPa.s.

EXAMPLES 12 TO 15 AND COMPARATIVE EXAMPLE 5

Production of Plastic Lens

[0148] Compositions were prepared by the blending shown in Table 3 and subjected to measurement on the viscosity and after the curing, on the refractive index, Abbe number and Barcol hardness and to evaluation on the dyeing speck, in the same manner as in Example 6. The results are shown in Table 3.

[0149] In Examples 12 to 15, the viscosity (25° C.) of each compound before curing was less than 100 mPa.s.

	TABLE 3
						Comparative
	Example 11	Example 12	Example 13	Example 14	Example 15	Example 5
Blending (parts	CR-39	95.0	90.0	95.0	95.0	85.0	100
by mass)	Sample A	5.0	10.0
	Sample B			5.0
	Sample C				5.0
	Sample D					15.0
Initiator IPP (parts by mass)	3	3	3	3	3	3
Physical	Refractive index (nD)	1.503	1.499	1.501	1.503	1.501	1.499
properties	Abbe number (νD)	56.1	60.0	53.6	56.1	64.2	51.6
	Barcol hardness	27	23	27	29	25	29
	Dyeing failure (number	1	1	1	1	0	8
	of defectives)

[0150] It is apparent from the results in Tables 1 and 2 that, according to the present invention, a plastic lens having high Abbe number and small curing shrinkage in percentage can be produced and at the same time, the curing time can be shortened.

[0151] Furthermore, it is apparent from the result in Table 3 that the plastic lens material of the present invention has an effect of improving dyeing of the polyethylene glycol bis(allyl carbonate) resin.

INDUSTRIAL APPLICABILITY

[0152] As verified in the foregoing pages, it is apparent that the compound of the present invention is a compound having small curing shrinkage in percentage as compared with conventional polyethylene glycol bis(allyl carbonate) resin and a cured product having high Abbe number can be produced therefrom similarly to the polyethylene glycol bis(allyl carbonate) resin.

[0153] Accordingly, more efficient production of plastic lenses can be attained than in conventional methods using polyethylene glycol bis(allyl carbonate) resin.

[0154] Furthermore, when the compound of the present invention is used by mixing it with polyethylene glycol bis(allyl carbonate) resin, dyeing specks generated in the dyeing of polyethylene glycol bis(allyl carbonate) resin can be improved.

Claims

1. A material for plastic lenses, comprising at least one group represented by the following formula (1) as a terminal group and a group represented by the following formula (2) as a repeating unit.

2. The material as claimed in claim 1, wherein the polyhydric alcohol is at least one selected from the compounds represented by the following structural formulae (7) to (13) and the following formula (14).

3. A process for producing a material as set forth in claim 1 or 2, comprising a step of transesterifying at least one selected from the compounds represented by the following formula (3) with the polyhydric alcohol described in claim 1 or 2 in the presence of a catalyst to obtain a plastic lens material:

4. The process as claimed in claim 3, wherein the catalyst is at least one member selected from the group consisting of tetraisopropoxy titanium, tetrabutoxy titanium, dibutyltin oxide, dioctyltin oxide, hafnium acetylacetonate and zirconium acetylacetonate.

5. A composition for plastic lenses, comprising at least one plastic lens material as set forth in claim 1 or 2.

6. A composition for plastic lenses, comprising from 0.1 to 10 parts by mass of at least one radical polymerization initiator per 100 parts by mass of a composition for plastic lenses as set forth in claim 5.

7. The composition for plastic lenses as claimed in claim 6, wherein the at least one radical polymerization initiator contains diisopropylperoxy dicarbonate.

8. The composition for plastic lenses as claimed in any one of claims 5 to 7, which has a viscosity at 25° C. of 1,000 mPa.s or less.

9. A plastic lens obtained by curing a composition for plastic lenses as set forth in any one of claims 5 to 8.

10. The plastic lens as claimed in claim 9, wherein a curing shrinkage in percentage at 23° C. is 10.0% or less.

11. A process for producing a plastic lens as set forth in claim 9 or 10, which comprises curing a plastic lens composition as set forth in claim 5 or 6.

12. The process as claimed in claim 11, wherein the plastic lens composition is cast polymerized at a temperature of 30 to 120° C. for 0.5 to 100 hours.