JPH07165859A - Composition for high-refractive-index plastic lens and lens made thereof - Google Patents

Abstract

PURPOSE:To obtain a composition useful for obtaining a lowly hygroscopic lens excellent in heat resistance, impact resistance and surface hardness by making it of a monomer mixture containing a specified polyisocyanate and a plurality of specified compounds. CONSTITUTION:This composition is prepared from a monomer mixture comprising at least one polyisocyanate represented by formula I (wherein X is H or CH3; R is Cl, Br, CH3 or C2H5; m is 0-4; and n is 2-4), 1,2-bis[(2-mercaptoethyl) thio]-3mercaptopropane represented by formula II, and at least one aromatic compound substituted by three or four mercaptomethyl groups [e.g. 1,2,4-tris(mercaptomethyl)benzene].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high refractive index plastic lens having excellent heat resistance, low water absorption and excellent surface hardness, which is used for various optical lenses such as spectacle lenses. To a composition for producing

[0002]

2. Description of the Related Art Plastic lenses are lighter in weight than inorganic lenses, are less likely to be broken, and can be dyed, and thus have recently become rapidly popular in the field of optical elements such as spectacle lenses and camera lenses. At present, as a resin widely used for these purposes, D obtained by casting polymerization of diethylene glycol bisallyl carbonate (hereinafter abbreviated as DAC) is used.
Some are made of AC resin. This DAC resin has the features of being lightweight, excellent in dyeability, and having good workability such as machinability and abrasivity, and is capable of meeting the needs of rich fashionability. Is. However, since the DAC resin has a lower refractive index than the inorganic lens, it is necessary to increase the center thickness, the edge thickness, and the curvature of the lens in order to obtain the optical characteristics equivalent to those of the glass lens. It is inevitable that it becomes thick. Therefore, a lens resin having a higher refractive index has been desired.

A polyurethane lens is known as a lens having a refractive index higher than that of a DAC resin. The present inventors have proposed, for example, USP-
Japanese Patent No. 4775733 (Japanese Patent Laid-Open No. 63-46213) proposes a polyurethane lens made of a polymer of a xylylene diisocyanate compound and a polythiol compound, and is widely used as an optical lens such as an eyeglass lens. There is. Further, as a polyurethane lens having a higher refractive index, for example, a polyurethane lens composed of a polymer of a trithiol compound and a polyisocyanate compound described in USP-5191055 (JP-A-2-270859) is proposed. However, these polyurethane lenses are generally inferior in heat resistance to olefin radical-polymerization type resins, for example, DAC resins, and therefore, dyeing of lenses that require heat treatment at about 60 to 90 ° C. is usually performed. When post-processing such as surface coating, the lens is likely to be deformed, and the thermal processing temperature must be kept low.

On the other hand, as a method of improving the heat resistance of the polyurethane resin, JP-A-2-275901 and EP408459 (JP-A-3-56525).
No. gazette) is known. However, JP-A-2-
The polyurethane resin composed of a polymer of two kinds of aliphatic polythiol compounds and aromatic polyisocyanate compounds described in JP-A-275901 has a refractive index of 1.5.
It is as low as about 7 to 1.61, and the polyurethane resin obtained by this method has a high water absorption rate. Therefore, a lens having a thin center thickness may absorb water and cause deformation in the center part of the lens. Furthermore, the surface hardness of the obtained resin is low,
It has a drawback that the molded lens is easily scratched. Further, the polyurethane resin made of a polymer of a polythiol compound having three or more reactive groups and a polyisocyanate compound described in EP-408459 has too high heat resistance, and therefore a lens is dyed by an ordinary method. Difficult to do.

Further, when 1,2,4- or 1,3,5-tris (mercaptomethyl) benzene or 1,2,4,5-tetrakis (mercaptomethyl) benzene is used alone as the thiol component, The use of xylylene diisocyanate as an isocyanate component is not preferable because of poor heat resistance of the resulting polyurethane resin, poor dyeability, low Abbe number and cloudiness. Furthermore, the thiol component used for the purpose of improving heat resistance may become solid. For example, 1,2,4-which is preferably used in the present invention
When 1,3,5-tris (mercaptomethyl) benzene or 1,2,4,5-tetrakis (mercaptomethyl) benzene has a relatively high melting point and a high viscosity, it is used alone as a thiol component. In addition, the handling of the lens is very complicated and the workability is poor.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a polyurethane lens comprising a polymer of a polyisocyanate compound and a polythiol compound, which provides flexibility in the selection of thermal conditions for post-processing such as dyeing and surface coating. In order to increase the heat resistance, a method of improving the heat resistance thereof is provided, and further, a lens having low water absorption and excellent surface hardness is provided.

[0007]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above-mentioned problems. That is, according to the present invention, as the component (a), at least one or more polyisocyanates represented by the general formula (1) (formula 3) and the component (b) represented by the formula (2) (formula 4) , 2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane, and at least one of three components of an aromatic compound substituted with three or four mercaptomethyl groups as the component (c). The present invention relates to a composition for a high refractive index plastic lens comprising a monomer mixture containing the same, and a high refractive index plastic lens comprising a sulfur-containing urethane resin obtained by polymerizing the composition.

[0008]

[Chemical 3] (In the formula, X represents a hydrogen atom or a methyl group, R represents a chlorine atom, a bromine atom, a methyl group or an ethyl group, m represents an integer of 0 to 4, and n represents an integer of 2 to 4)

[0009]

[Chemical 4]

The present invention will be described in detail below. The component (a) in the present invention is a compound represented by the general formula (1), and specifically, o-xylylene diisocyanate,
m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethyl-p-xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate, and their nuclear chlorinated compounds, brominated compounds, methylated compounds, ethylated compounds, etc. , For example, 4-chloro-m-xylylene diisocyanate, 4,5-dichloro-m-xylylene diisocyanate, 2,3,5,6-tetrabromo-p-xylylene diisocyanate, 4-methyl-m-
Examples include xylylene diisocyanate and 4-ethyl-m-xylylene diisocyanate. Some of these are commercially available. 1,2-bis [(2-mercaptoethyl) thio] -3- represented by formula (2) which is the component (b)
Mercaptopropane can be easily produced by the method described in JP-A-2-270859, that is, a method in which epihalohydrin and 2-mercaptoethanol are reacted and then thiourea is reacted.

The aromatic compound substituted with three or four mercaptomethyl groups as the component (c) is, for example, 1,2,3-tris (mercaptomethyl).
Benzene, 1,2,4-tris (mercaptomethyl) benzene or 1,3,5-tris (mercaptomethyl)
Benzene, 1,2,3,4-tetrakis (mercaptomethyl) benzene, 1,2,3,5-tetrakis (mercaptomethyl) benzene, or 1,2,4,5-tetrakis (mercaptomethyl) benzene Can be mentioned. Many of these compounds are known compounds described in the literature, and can be simply produced by a method described in the literature from compounds that are inexpensive and easily available. For example, M. Nakazaki,
et.al., J. Org. Chem., 43, 1041 (1978), T. Otsub.
o, et.al., Bull. Chem. Soc. Jpn., 62164 (1989)
The corresponding benzoic acid derivative,
Alternatively, it can be produced by reducing the ester derivative to a benzyl alcohol derivative by an appropriate method, converting it into a benzyl halide derivative, reacting it with thiourea, and hydrolyzing it. These compounds may be used alone or in combination.
In the present invention, of these compounds, xylylene diisocyanate is preferably used as the component (a) and 1,2,4-tris (mercaptomethyl) benzene is preferably used as the component (c).

The ratio of each component used in the present invention, that is,
At least one polyisocyanate represented by the general formula (1) of the component (a), and at least one polythiol represented by the formula (2) of the component (b) and the aromatic thiol compound of the component (c). The use ratio with the above is an NCO group / SH group ratio in the range of 0.5 to 1.5, preferably 0.6 to 1.4, and most preferably 0.7 to 1.3. is there. The aromatic thiol compound as the component (c) is in the range of 5 to 50% by weight, preferably 10 to 45% by weight, and most preferably 12 to 40% by weight, based on the whole polythiol component. If this aromatic thiol compound is less than 5% by weight with respect to the entire polythiol component, it is difficult to obtain sufficient heat resistance, and if it exceeds 50% by weight, heat resistance becomes too high. It tends to be difficult to dye. Ingredient (c)
The ratio of the thiol compound used is that of the component (a) used
And the compound of component (c), and various physical properties required for the obtained lens.

In the present invention, a polymerization catalyst for accelerating the polymerization reaction, an ultraviolet absorber for improving weather resistance, an antioxidant, an anti-coloring agent, a fluorescent dye, a light stabilizer, an oil-soluble dye, and other additives. May be added as needed. The lens of the present invention is produced by at least one of the polyisocyanates represented by the general formula (1) of the component (a), the polythiol represented by the formula (2) of the component (b), and the component (c ) A monomer mixture containing at least one or more of the aliphatic thiol compounds, if necessary, with additives, known cast polymerization method, that is, a glass or metal mold and a resin gasket It is carried out by injecting the mixed liquid into a mold that is a combination of the above and heating and curing. At this time, the mold may be subjected to a known release treatment in order to facilitate the removal of the resin after molding.

Further, in the present invention, the compound of the component (c) may be mixed with the compound of the component (b) in advance in order to simplify the workability during the production of the lens. Particularly, when the component (c) is solid, it is preferably dissolved in the compound of the component (b) in advance. In this case, since the compound of component (b) is a low-viscosity liquid, the compound of component (c) can be easily dissolved. The polymerization temperature and the polymerization time in the cast polymerization are different depending on the composition of the monomer, the kind and the amount of the additive, but generally, the temperature rise is started from 5 to 20 ° C. and 100 ° C. to 1 ° C.
The temperature is raised to about 30 ° C. in 8 to 30 hours.

The lens obtained in the present invention is improved in antireflection, high hardness, abrasion resistance, chemical resistance, antifogging property or fashionability, if necessary. Physical or chemical treatments such as surface polishing, antistatic treatment, hard coat treatment, anti-reflection coat treatment, dyeing treatment and light control treatment can be applied. Further, the lens obtained in the present invention can be easily dyed in water or a solvent by using an ordinary disperse dye. At the time of dyeing, a carrier which is a dyeing aid may be added to the dyeing bath to further facilitate dyeing. The sulfur-containing urethane resin of the present invention has an extremely low dispersion, a high refractive index, excellent heat resistance, is colorless and transparent, is lightweight, has excellent weather resistance and impact resistance, and further has low water absorption and a surface. It has excellent hardness and is suitable not only as a material for optical elements such as spectacle lenses and camera lenses but also as a material for glazing materials, paints and adhesives.

[0016]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, the part shown in an Example shows a weight part.
The performance test of the obtained lens was evaluated by the following test methods.・ Refractive index, Abbe number: 20 ° C using Pulfrich refractometer
It was measured at.・ Appearance: Visual observation.・ Heat resistance: Thermomechanical analyzer TAS300
(Manufactured by Rigaku Denki), load 5g on the test piece, and
It was heated in minutes and its thermal deformation start temperature was measured. Dyeability: ML-Yellow, ML-Red, which are disperse dyes for plastic lenses manufactured by Mitsui Toatsu Dye Co., Ltd.
ML-Blue was immersed in an aqueous solution of 5 g / L each for 5 minutes for immersion at 95 ° C. to dye a plate having a thickness of 9 mm. After staining, spectrophotometer, U-
The transmittance of 400 to 700 nm was measured using 2000 (manufactured by Hitachi, Ltd.). As a comprehensive evaluation, those having good dyeability were evaluated as (◯), and those having poor dyeability or being unable to be dyed at all were evaluated as (x). Dyeing heat resistance: After immersion in a dyeing bath at 95 ° C. for 5 minutes, it was visually observed whether or not the lens was deformed. Water absorption rate: A test piece was prepared based on JIS-K-7209, immersed in water at room temperature for 48 hours, and the water absorption rate was measured from the weight change thereafter. -Surface hardness: Pencil hardness was measured using the pencil scratch tester for coating film of JIS-K-5401.

Example 1 45.7 parts of m-xylylene diisocyanate (0.24)
Mol), 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 33.7 parts (0.13 mol), 1,2,4-tris (mercaptomethyl) benzene 7.0 parts ( 0.032 mol) and 0.01% by weight of dibutyltin dilaurate (relative to the total amount of the mixture) to form a uniform liquid, and after sufficiently defoaming, a mold composed of a glass mold and a gasket that have been subjected to a mold release treatment. Poured into molds. Then, the temperature was gradually raised from 40 ° C. to 120 ° C., and heat curing was performed for 20 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin is colorless and transparent, has excellent impact resistance, and has a refractive index n _d = 1.
66, Abbe number ν _d = 32, thermal deformation start temperature is 1
It was 00 ° C. The lens did not deform even when dyed in a dyeing bath at 95 ° C. The transmittance after dyeing is ML-Yello
w was 31%, ML-Red was 38%, ML-Blue was 48%, and the overall evaluation of the dyeability was (◯). Four
The water absorption rate after 8 hours was 0.03%, and the surface hardness was H.

Example 2 29.2 parts of m-xylylene diisocyanate (0.16
Mol), 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 20.2 parts (0.08 mol), 1,3,5-tris (mercaptomethyl) benzene 5.1 parts ( 0.024 mol) and 0.01% by weight of dibutyltin dilaurate (relative to the total amount of the mixture) to form a uniform liquid, and after sufficiently defoaming, a mold composed of a glass mold and a gasket that have been subjected to a mold release treatment. Poured into molds. Then, the temperature was gradually raised from 40 ° C. to 120 ° C., and heat curing was performed for 20 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin is colorless and transparent, has excellent impact resistance, and has a refractive index n _d = 1.
66, Abbe number ν _d = 31, thermal deformation start temperature is 9
It was 9 ° C. The transmittance after dyeing is ML-Yellow.
32% for ML-Red, 36% for ML-Red, 4 for ML-Blue
It was 4%, and the overall evaluation of the dyeability was (◯). 48
The water absorption after the lapse of time was 0.03%, and the surface hardness was H.

Example 3 65.4 parts of m-xylylene diisocyanate (0.35
Mol), 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 44.9 parts (0.17 mol), 1,2,4,5-tetrakis (mercaptomethyl) benzene 11.3 Parts (0.043 mol) and 0.01% by weight of dibutyltin dilaurate (relative to the total amount of the mixture) to form a uniform liquid, and after sufficiently degassing, from a glass mold and a gasket that have been subjected to a mold release treatment. It was poured into a mold mold. Then, the temperature was gradually raised from 40 ° C. to 120 ° C., and heat curing was performed for 20 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin was colorless and transparent and had excellent impact resistance, a refractive index n _d = 1.66, an Abbe number ν _d = 32, and a thermal deformation starting temperature of 106 ° C. The transmittance after dyeing is ML
-Yellow 28%, ML-Red 34%, ML
-Blue is 41%, and the overall evaluation of dyeability is (○)
Met. The water absorption rate after 48 hours was 0.03%, and the surface hardness was H.

Comparative Example 1 39.1 parts (0.21) of m-xylylene diisocyanate
Mol) and 1,2,4-tris (mercaptomethyl) benzene 30.0 parts (0.14 mol) to prepare a uniform solution,
After sufficiently defoaming, the mixture was poured into a mold made of a glass mold and a gasket that had been subjected to a mold release treatment. Then 4
While gradually raising the temperature from 0 ° C. to 120 ° C., it was heated and cured for 20 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin was colorless and transparent, had excellent impact resistance, had a refractive index n _d = 1.67, had an Abbe number ν _d = 28, and had a thermal deformation starting temperature of 132 ° C. The transmittance after dyeing is 61% in ML-Yellow,
It was 77% for ML-Red and 78% for ML-Blue, and the overall evaluation of dyeability was (x). The water absorption rate after 48 hours was 0.2%, and the surface hardness was H.

Comparative Example 2 31.1 parts of m-xylylene diisocyanate (0.17
23.8 parts (0.11 mol) of 1,3,5-tris (mercaptomethyl) benzene to form a uniform liquid, and after sufficiently defoaming, a glass mold and a gasket subjected to a mold release treatment. Was injected into the mold mold. Then, while gradually raising the temperature from 40 ° C. to 120 ° C.,
It was heat-cured over time. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin was excellent in impact resistance, but was cloudy. Refractive index n
_d = 1.66, and the Abbe number ν _d = 29, the thermal deformation starting temperature of 130 ° C.. The transmittance after dyeing is ML-Y
Ellow 79%, ML-Red 80%, ML-B
It was 86% with lue, was not dyed, and the overall evaluation of the dyeability was (x). The water absorption rate after 48 hours was 0.2%, and the surface hardness was H.

Comparative Example 3 m-xylylene diisocyanate 64.1 parts (0.34
Mol), 1,2,4,5-tetrakis (mercaptomethyl) benzene 44.6 parts (0.17 mol) to form a uniform liquid, and after sufficiently defoaming, a glass mold subjected to a mold release treatment. It was poured into a mold made of a gasket. Then, while gradually raising the temperature from 40 ° C to 120 ° C, 2
It was heat-cured for 0 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin is colorless and transparent, has excellent impact resistance, and has a refractive index n _d = 1.6.
6, Abbe number ν _d = 29, thermal deformation start temperature is 12
It was 9 ° C. The transmittance after dyeing is ML-Yellow.
68%, ML-Red 71%, ML-Blue 7
It was 5%, and the overall evaluation of dyeability was (x). 48
The water absorption rate after time is 0.2%, and the surface hardness is H.
Met.

Comparative Example 4 65.4 parts of m-xylylene diisocyanate (0.35
Mol), 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 60.1 parts (0.23 mol), and dibutyltin dilaurate 0.1% by weight (based on the total amount of the mixture). The mixture was mixed into a uniform liquid, sufficiently defoamed, and then poured into a mold made of a mold-treated glass mold and a gasket. Then, from 40 ℃ to 12
While gradually raising the temperature to 0 ° C., it was heated and cured for 20 hours. After the polymerization was completed, the polymer was slowly cooled and the polymer was taken out from the mold. The obtained resin was colorless and transparent, had excellent impact resistance, had a refractive index n _d = 1.66, Abbe number ν _d = 33, and had a thermal deformation starting temperature of 84 ° C. The lens was deformed when dyed in a dyeing bath at 95 ° C. The transmittance after dyeing is
24% for ML-Yellow, 31% for ML-Red,
It was 40% in ML-Blue, and the overall evaluation of dyeability was (◯).

[0024]

The plastic lens made of the sulfur-containing urethane resin obtained by polymerizing the monomer mixture containing the three components of the present invention comprises the polyisocyanate represented by the general formula (1) and the polythiol represented by the formula (2). Without damaging the physical properties of the plastic lens obtained by polymerization,
It is an extremely excellent high-refractive-index plastic lens with improved heat resistance, which is its drawback.

Claims (4)

[Claims] 1. A compound represented by the general formula (1) (formula 1) as the component (a):
At least one or more polyisocyanates represented by: (In the formula, X represents a hydrogen atom or a methyl group, R represents a chlorine atom, a bromine atom, a methyl group or an ethyl group, m represents 0 to 4, and n represents an integer of 2 to 4) Component (b) 1,2-represented by the formula (2)
Bis [(2-mercaptoethyl) thio] -3-mercaptopropane, A high refractive index plastic lens composition comprising a monomer mixture containing, as component (c), three components of at least one aromatic compound substituted with three or four mercaptomethyl groups. 2. The NCO group and the SH group are 0.5 to 1.5 in the ratio of NCO group / SH group, and the component (c) is 5 to 50% by weight of the total polythiol component. Item 1. A composition for a high refractive index plastic lens according to Item 1. 3. The high refractive index plastic according to claim 1, wherein the component (a) is xylylene diisocyanate and the component (c) is 1,2,4-tris (mercaptomethyl) benzene. Lens composition. 4. A high-refractive-index plastic lens made of a sulfur-containing urethane resin obtained by polymerizing the lens composition according to any one of claims 1 to 3.