JP3270581B2 - Composition and lens for high refractive index plastic lens - Google Patents

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. A composition for manufacturing.

[0002]

2. Description of the Related Art Plastic lenses are lighter than inorganic lenses, are less likely to break, and can be dyed. Therefore, plastic lenses have been rapidly spreading in the field of optical elements such as spectacle lenses and camera lenses in recent years. At present, resins widely used for these purposes include cast-polymerized diethylene glycol bisallyl carbonate (hereinafter abbreviated as DAC).
Some are made of C resin. This DAC resin has features such as being lightweight, being excellent in dyeability, and having good workability such as cutting property and polishing property,
It can respond to the needs of fashion.
However, since the refractive index of a DAC resin is lower than that of an inorganic lens, it is necessary to increase the center thickness, the edge thickness, and the curvature of the lens in order to obtain optical characteristics equivalent to those of a glass lens. Thickness is inevitable.
For this reason, a lens resin having a higher refractive index has been desired.

A polyurethane lens is known as a lens having a higher refractive index than a DAC resin. The present inventors have proposed, for example, USP-
No. 4,775,733 (JP-A-63-46213) proposes a polyurethane lens made of a polymer of a xylylene diisocyanate compound and a polythiol compound, and is widely used in optical lenses such as spectacle lenses. I have. Further, as a polyurethane lens having a higher refractive index, for example, a polyurethane lens described in US Pat. No. 5,191,055 (JP-A-2-270859) has been proposed. However, these polyurethane lenses are generally inferior in heat resistance to radical polymerization type resins of olefin groups, for example, DAC resins, and therefore, usually require dyeing of lenses requiring heat processing at about 60 to 90 ° C. During post-processing such as surface coating, there is a disadvantage that the lens is likely to be deformed and the heat processing temperature must be kept low.

On the other hand, as a method for improving the heat resistance of a polyurethane resin, JP-A-2-275901 and EP4088459 (JP-A-3-56525).
Is known. However, JP-A-2-
The polyurethane resin described in Japanese Patent No. 275901 has a low refractive index of about 1.57 to 1.61, and the polyurethane resin obtained by this method has a high water absorption. Water absorption may cause deformation of the center of the lens. Further, there is a disadvantage that the surface hardness of the obtained resin is low and the molded lens is easily scratched. Further, the polyurethane resin described in EP-408449 has too high heat resistance, so that it is difficult to dye a lens by a normal method. Furthermore, it is disclosed that when pentaerythrithiol [tetrakis (mercaptomethyl) methane of the present invention] is used as the thiol component, xylylene diisocyanate is not preferably used as the isocyanate component.

Further, in these prior arts, the thiol component used for the purpose of improving heat resistance sometimes becomes solid. For example, tetrakis (mercaptomethyl) methane, which is preferably used in the present invention, is a solid having a melting point of 72 to 73 ° C., and as described in EP-40859, when used alone as a thiol component, a lens is required. In the molding operation, the handling becomes very complicated. Further, the compound represented by the general formula (3) (Chemical Formula 3) described in JP-A-2-275901 usually has a high viscosity, so that tetrakis (mercaptomethyl) methane is mixed as the component (c). In this case, if the mixing ratio is increased, crystals are precipitated, and the handling is complicated and the workability is poor. In addition, the mixing ratio of tetrakis (mercaptomethyl) methane is limited, and thus the heat resistance is sufficiently improved. Can not do.

[0006]

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[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyurethane lens made of a polymer of a polyisocyanate compound and a polythiol compound with a degree of freedom in selecting thermal conditions in post-processing such as dyeing and surface coating. It is an object of the present invention to provide a method for improving the heat resistance of the lens, and to provide a lens having low water absorption and excellent surface hardness.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have arrived at the present invention. That is, the present invention provides at least one kind of polyisocyanate represented by the general formula (1) (formula 4) as the component (a) and 1 represented by the formula (2) (formula 5) as the component (b). , 2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane, and x (x is 0 or an integer of 1 or more) hydroxyl groups and y (y is an integer of 1 or more) as component (c) ) And the total number (x + y) of hydroxyl groups and mercapto groups is 3 or more
And has no ring structure in the molecule in which the number of carbon atoms interposed between the most distant hydroxyl groups or mercapto groups or between the most distant hydroxyl group and the mercapto group is 5 or less.
There at least one or more aliphatic thiol compounds, high index composed of a monomer mixture a high refractive index plastic lens composition comprising, and sulfur-containing urethane resin obtained by polymerizing the composition comprising the three components of It concerns plastic lenses.

[0009]

Embedded image (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.)

[0010]

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Hereinafter, the present invention will be described in detail. The component (a) in the present invention is a compound represented by the general formula (1), specifically, o-xylylene diisocyanate,
m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethyl-p-xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate, and their chlorinated, brominated, methylated or ethylated products For example, 4-chloro-m-xylylene diisocyanate, 4,5-dichloro-m-xylylene diisocyanate, 2,3,5,6-tetrabromo-p-xylylene diisocyanate, 4-methyl-m-
Xylylene diisocyanate, 4-ethyl-m-xylylene diisocyanate, and the like. Some of these are commercially available. 1,2-bis [(2-mercaptoethyl) thio] -3- represented by the 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 is reacted with 2-mercaptoethanol, and then thiourea is reacted.

Further, x (x is 0 or an integer of 1 or more) hydroxyl groups and y (y is an integer of 1 or more) component (c) are used.
Having a mercapto group and a total of a hydroxyl group and a mercapto group
The number (x + y) is 3 or more, and a ring structure is formed in a molecule in which the number of carbon atoms interposed between the most distant hydroxyl groups or between mercapto groups or between the most distant hydroxyl group and the mercapto group is within 5 Examples of the aliphatic thiol compound having no such compound include monothioglycerol, dithioglycerol, trithioglycerol, dimercaptopropanol, 1-mercaptomethyl-1,1-dihydroxymethylpropane, and 1,4-dimercapto-2,3. - di arsenide <br/> Dorokishibutan, tetrakis (mercaptomethyl) methane, 1,1,1-tris (mercaptomethyl) ethane,
1,1,1-tris (mercaptomethyl) propane and the like can be mentioned. Some of these compounds are commercially available and readily available. These compounds may be used alone or as a mixture. In the present invention, among these compounds, xylylene diisocyanate is preferably used as component (a), and tetrakis (mercaptomethyl) methane is preferably used as component (c).

The use ratio of each component in the present invention, that is,
At least one kind of the polyisocyanate represented by the general formula (1) of the component (a) and at least one kind of the polythiol represented by the formula (2) of the component (b) and the aliphatic thiol compound of the component (c) The above usage ratios are in the range of 0.5 to 1.5 in the ratio of NCO groups / (SH + OH) groups. The aliphatic thiol compound as the component (c) is used in an amount of 5 to 50% by weight based on the whole polythiol component. If this aliphatic thiol compound is less than 5% by weight with respect to the whole polythiol component, a sufficient improvement in heat resistance cannot be obtained, and if it exceeds 50% by weight, the heat resistance becomes too high. It is difficult to dye easily. The use ratio of the thiol compound of the component (c) is as follows:
It is appropriately determined depending on the compound of the component (a) and the compound of the component (c) to be used and various physical properties required for the obtained lens.

In the present invention, additives such as a polymerization catalyst for accelerating a polymerization reaction, an ultraviolet absorber for improving weather resistance, an antioxidant, a coloring inhibitor, a fluorescent dye, a light stabilizer, and an oil-soluble dye. May be added as needed. The production of the lens of the present invention is carried out by preparing at least one kind of the polyisocyanate 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 aliphatic thiol compound, if necessary, by adding an additive to the mixture by a known casting polymerization method, that is, a glass or metal mold and a resin gasket. This is performed by injecting the mixed liquid into a mold combined with the above and heating and curing the mixture. At this time, a known release treatment may be applied to the mold in order to facilitate removal of the resin after molding.

In the present invention, the compound of the component (c) may be previously mixed with the compound of the component (b) in order to simplify the workability during the production of the lens. In particular, when the component (c) is a solid, it is preferable to dissolve it in the compound of the component (b) in advance. In this case, since the compound of the component (b) is a low-viscosity liquid, the compound of the component (c) can be easily dissolved. The polymerization temperature and the polymerization time in the casting polymerization vary depending on the composition of the monomer, the type and the amount of the additive, but generally, the temperature is raised from 5 to 20 ° C.
The temperature is raised to about 30 ° C. in 8 to 30 hours.

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

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. 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 a Pulfrich refractometer
Was measured.・ Appearance: Observed visually. Heat resistance: Using a thermomechanical analyzer (manufactured by PerkinElmer (USA)), 5 g of weight was applied to the test piece, and 2.
Heating was performed at 5 ° C./min, and the thermal deformation onset temperature was measured. Dyeability: ML-Yellow, ML-Red, which are disperse dyes for plastic lenses manufactured by Mitsui Toatsu Dye Co., Ltd.
Each ML-Blue was immersed at 95 ° C. for 5 minutes in a dyeing tank prepared in an aqueous solution of 5 g / l to dye a 9 mm-thick plate. After staining, Spectrophotometer, U-
The transmittance of 400 to 700 nm was measured using 2000 (manufactured by Hitachi, Ltd.). As an overall evaluation, a sample having good dyeability was rated as (）), and a sample having poor dyeability or not dyeable at all was rated as (x). Dyeing heat resistance: After immersion in a dyeing bath at 95 ° C. for 5 minutes, whether or not the lens was deformed was visually observed. -Water absorption: A test piece was prepared based on JIS-K-7209, immersed in water at room temperature for 48 hours, and the water absorption was measured from the weight change thereafter. Surface hardness: Pencil hardness was measured using a JIS-K-5401 pencil scratch tester for coating films.

Example 1 69.6 parts of m-xylylene diisocyanate (0.37
Mol), 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 44.8 parts (0.17 mol), tetrakis (mercaptomethyl) methane 11.2
Part (0.06 mol), dibutyltin dilaurate 0.1
% By weight (based on the total amount of the mixture) was mixed to form a uniform liquid, sufficiently degassed, and then poured into a mold including a glass mold and a gasket subjected to a release treatment. Then, while gradually raising the temperature from 40 ° C. to 120 ° C.,
Heat-cured over time. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of 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 = 32, and thermal deformation onset temperature is 11
4 ° C. The lens was not deformed when dyed in a dye bath at 95 ° C. The transmittance after staining was ML-Yel
30% for low, 37% for ML-Red, ML-Blu
e was 47%, and the overall evaluation of the dyeability was (（). The water absorption after 48 hours was 0.04%, and the surface hardness was 2H.

Example 2 96.0 parts of m-xylylene diisocyanate (0.51 parts)
Mol), 1,3-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 36.4 parts (0.14 mol), 1,1,1-tris (mercaptomethyl) propane 36.4 (0 .20 mol) and 0.1% by weight of dibutyltin dilaurate (based on the total amount of the mixture) to form a uniform liquid, which was sufficiently defoamed and then subjected to a mold release treatment. Injected into mold. Then, the mixture was cured by heating for 20 hours while gradually raising the temperature from 40 ° C. to 120 ° C. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin is colorless and transparent, has excellent impact resistance, and has a refractive index n _d = 1.
65, Abbe number ν _d = 33, and thermal deformation onset temperature is 1
20 ° C. The lens was not deformed when dyed in a dye bath at 95 ° C. The transmittance after staining was ML-Ye
37% at low, 44% at ML-Red, ML-Bl
ue was 54%, and the overall evaluation of dyeability was (（). The water absorption after 48 hours was 0.04%, and the surface hardness was 2H.

Comparative Example 1 65.4 parts of m-xylylene diisocyanate (0.35
Mol), 60.1 parts (0.23 mol) of 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane and 0.1% by weight of dibutyltin dilaurate (based on the total amount of the mixture). After mixing to form a uniform liquid and sufficiently defoaming, the mixture was poured into a mold having a release mold and a gasket. Then, from 40 ° C to 12
While gradually raising the temperature to 0 ° C., the composition was cured by heating for 20 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, had excellent impact resistance, had a refractive index n _{d of} 1.66, an Abbe number ν _{d of} 33, and had a thermal deformation initiation temperature of 98 ° C. Heat resistance was inferior to the lens obtained in Example 1, and the lens was deformed when dyed in a dyeing bath at 95 ° C. The transmittance after staining was ML-Yel
24% for low, 31% for ML-Red, ML-Blu
e was 40%, and the overall evaluation of the dyeability was (（).

Comparative Example 2 According to Example 2 of EP-408449, 65.4 parts (0.35 mol) of m-xylylene diisocyanate, 29.2 parts (0.17 mol) of dithioerythritol, dibutyl 0.1 g of tindilaurate (based on the total amount of the mixture) was mixed to form a uniform liquid, sufficiently defoamed, and then poured into a mold having a release-treated glass mold and a gasket. Then, from 40 ° C to 12
While gradually raising the temperature to 0 ° C., the composition was cured by heating for 20 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, excellent in impact resistance, refractive index n _d = 1.61, Abbe number ν _d = 33, and thermal deformation onset temperature was 165 ° C. The lens was not deformed when dyed in a dye bath at 95 ° C. The transmittance after staining was 85% for ML-Yellow and ML-R
It was 86% in ed and 86% in ML-Blue, and was not stained. The overall evaluation of staining was (x).

Comparative Example 3 45.0 parts (0.09 mol) of pentaerythritol tetrakis (3-mercaptopropionate), 5.0 parts (0.02 mol) of tetrakis (mercaptomethyl) methane
Was mixed and heated to obtain a uniform liquid. When this liquid was cooled to room temperature, tetrakis (mercaptomethyl) methane was precipitated.

Comparative Example 4 m-xylylene diisocyanate 41.2 parts (0.22
Mol), 47.5 parts (0.10 mol) of pentaerythritol tetrakis (3-mercaptopropionate), 2.5 parts (0.09 mol) of tetrakis (mercaptomethyl) methane
1 mol) and 0.1% by weight of dibutyltin dilaurate (based on the total amount of the mixture) to form a uniform liquid, sufficiently degassed, and then subjected to a mold release treatment. Injected into mold. Then, 40
While gradually raising the temperature from 120 ° C. to 120 ° C., heat curing was performed for 20 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin is colorless and transparent, excellent in impact resistance, refractive index n _d = 1.60, Abbe number ν.
_d = 36, the thermal deformation initiation temperature was 97 ° C., and the lens had a lower refractive index and lower heat resistance than the lens obtained in Example 1. The lens deformed when dyed in a dye bath at 95 ° C. The transmittance after staining was 24 in ML-Yellow.
%, ML-Red was 31%, and ML-Blue was 40%, and the overall evaluation of the staining was (）). The water absorption after 48 hours was 0.12%, which was higher than that of Example 1. The surface hardness was HB, which was inferior to that of Example 1.

[0024]

According to the present invention, a plastic lens comprising a sulfur-containing urethane resin obtained by polymerizing a monomer mixture containing three components comprises a polyisocyanate of the general formula (1) and a polythiol of the formula (2). Without impairing the physical properties of the plastic lens obtained by polymerization,
This is a very high-refractive-index plastic lens with improved heat resistance as a drawback.

Continuation of the front page (56) References JP-A-2-275901 (JP, A) JP-A-2-270859 (JP, A) JP-A-3-236386 (JP, A) JP-A-5-148340 (JP, A) JP-A-5-320301 (JP, A) JP-A-6-256342 (JP, A) JP-A-1-295202 (JP, A) JP-A-3-56525 (JP, A) JP-A-3-78801 (JP, A) JP-A-3-84021 (JP, A) JP-A-5-307101 (JP, A) JP-A-5-78441 (JP, A) JP-A-1-302202 (JP, A) A) WO 93/1233 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. Component (a) represented by the general formula (1)
At least one polyisocyanate represented by the following formula: (Wherein 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). 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane represented by formula (2): Component (c) has x (x is 0 or an integer of 1 or more) hydroxyl groups and y (y is an integer of 1 or more) mercapto groups, and the total number of hydroxyl groups and mercapto groups (x + y) is : 3
Or more, and a ring structure is formed in the molecule in which the number of carbon atoms interposed between the most distant hydroxyl groups or mercapto groups or between the most distant hydroxyl group and the mercapto group is 5 or less.
A composition for a high refractive index plastic lens, comprising a monomer mixture containing three components of at least one aliphatic thiol compound not having. 2. The method according to claim 1, wherein the NCO group and the (OH + SH) group
Group / (OH + SH) group ratio of 0.5 to 1.5,
The composition for a high-refractive-index plastic lens according to claim 1, wherein the component (c) is 5 to 50% by weight of the total components of the polythiol. 3. The composition for a high refractive index plastic lens according to claim 1, wherein the component (a) is xylylene diisocyanate and the component (c) is tetrakis (mercaptomethyl) methane. 4. A high refractive index plastic lens comprising a sulfur-containing urethane resin obtained by polymerizing the lens composition according to claim 1.