JPH1039101A - High refractive index plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a high refractive index and to prevent the emission of an offensive or foul odor peculiar to sulfur at the time of working a lens by using two kinds of compds. represented by specified formulae as polythiols and polyisocyanates including xylylene diisocyanate as polyisocyanates. SOLUTION: Two kinds of compds. represented by formulae I, II are used as polythiols and polyisocyanates including xylylene diisocyanate are used as polyisocyanates to obtain the objective high refractive index plastic lens having a refractive index of >=1.64 and an Abbe's number of >=30. In the formulae I, II, R is polyvalent 2-9C alicyclic hydrocarbon, (l) is an integer of 1-3, (m) is an integer of 2-4 and (n) is an integer of 2-4. The polythiols preferably include 40-80% of the compd. represented by the formula I and 20-60% of the compd. represented by the formula II. The polyisocyanates preferably include >=50wt.% xylylene diisocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sulfur-containing plastic lens having a high refractive index. More specifically, the present invention relates to a plastic lens which does not generate a peculiar smell or odor peculiar to sulfur in a cutting / polishing process of a sulfur-containing lens molded body obtained by casting polymerization. The sulfur-containing plastic lens of the present invention is used for eyeglasses, optical materials, and the like.

[0002]

2. Description of the Related Art Plastic lenses are lighter and harder to break than inorganic lenses and can be dyed. Therefore, plastic lenses have recently been rapidly used in optical devices such as spectacle lenses and camera lenses. However, considering optical plastics for eyeglass lenses, how to increase the refractive index has been an important issue. That is, when an eyeglass lens is manufactured using an optical plastic having a small refractive index compared to an inorganic lens, in order to obtain optical properties equivalent to a glass lens, it is necessary to increase the center thickness, edge thickness, and curvature of the lens. There is. Therefore, the spectacle lens becomes thicker as a whole, and it is inevitable that the eyeglass lens goes against the recent market trend in which much emphasis is placed on fashionability. For this reason, even at the present when plastic spectacle lenses having a refractive index of more than 1.64 have become widespread, eyeglass lens manufacturers continue to strongly demand that the resin for lens having a higher refractive index be released as soon as possible.

[0003] In order to increase the refractive index of a resin, a method of introducing a heavy metal atom, a halogen atom, a sulfur atom, or an aromatic compound into a polymer molecule is known. Above all, the method of introducing a sulfur atom is the most important because it can keep the Abbe number, which is an important index of the optical performance of the resin, high and can realize an optical resin with excellent weather resistance and little impact on waste environment. Research has been done energetically. As a result, for example, sulfur-containing urethane-based resins composed of polyisocyanate and polythiol (JP-A-60-199016, JP-A-62-267316,
JP-A-63-46213), polythio (meth) acrylate resins (JP-A-64-26613, JP-A-64-31759, JP-A-63-26313)
188660) or sulfur-containing poly (meth) acrylate resins (JP-A-62-283109, JP-A-63-268707) and the like. Above all, a sulfur-containing urethane-based resin composed of polyisocyanate and polythiol can provide an ultra-high-refractive-index spectacle lens having a refractive index of more than 1.64, and can provide safe spectacles excellent in impact resistance. For reasons
Widespread in the market.

By the way, in order to secure excellent physical properties such as a refractive index of 1.64 or more and an Abbe number of 30 or more in these resins, a polythiol having a sulfur content occupying more than half of its molecular weight is required. Compounds must be used. Eyeglass lenses that have achieved a high refractive index using such a polythiol compound having a high sulfur content as a raw material monomer have been widely used after more than five years from launch, but have a problem of generation of odors and odors during processing. It has become. That is, before the spectacles are passed on to the consumer, a flattening process is required to adjust the shape of the lens to the spectacle frame. At this time, since the lens is exposed to a high temperature, part of the lens material is thermally The substance may be decomposed into odors, generating an off-odor and an odor peculiar to sulfur. This process is often performed at eyeglass retailers, which gives the customer an unpleasant impression. In addition, if ventilation or deodorizing equipment is introduced to remove off-flavors and odors at the time of Kobazuri processing, an economic burden is imposed on retailers. Under these circumstances, high-refractive-index spectacle lenses, which have a refractive index of 1.64 or more and have an Abbe number of 30 or more and have excellent physical properties, have become widely used at present.
As described above, there is an urgent need to create an ultra-high refractive index spectacle lens that maintains an Abbe number of 30 or more and does not generate odor during processing.

[0005] For plastic lenses, processing methods for reducing or eliminating odors and odors generated during cutting and polishing have been desired, and some measures have already been proposed. For example, in the production of a high-refractive-index plastic lens having a crosslinked structure having a refractive index of 1.50 or more, which is a radical polymerization type, 0.05%
2-5664 is a technology to alleviate off-flavors and odors during lens cutting and polishing by using resin containing up to 1%.
It is disclosed in 1. However, sulfur-containing plastic lenses were studied using the fragrance imparting compounds disclosed herein.
It is already known that it is insufficient to reduce or deodorize bad smells (Japanese Patent Laid-Open No. 5-273401).

Further, a method of reducing odor by adding a surfactant during processing of a sulfur-containing plastic lens (Japanese Patent Laid-Open No.
256558), a method of reducing odor by using water to which an oxidizing agent is added during processing of a sulfur-containing plastic lens (Japanese Unexamined Patent Publication No.
228816), a method of reducing odor by using a metal oxide impregnated carbon during processing of a sulfur-containing plastic lens (JP-A-5-25
3839) has been proposed. Certainly, although these methods can reduce some of the irritating odors, in order to remove the sulfur odor to a degree that does not cause any discomfort to the surroundings when processed in a small store, It was necessary to use it with simple ventilation equipment. Further, at the time of producing a sulfur-containing plastic lens, a method of adding a fragrance to the monomer composition to reduce odor (Japanese Patent Application Laid-Open Nos. 5-273401 and 5-205)
297201) have also been proposed. However, fragrances are a matter of personal taste and are not a universal method. In other words, even if the sulfur odor can be reduced, if the fragrance of the fragrance used in the mask does not match the taste of the customer, the result is ineffective or equivalent.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sulfur-containing plastic lens having a high refractive index which does not generate a peculiar smell or odor peculiar to sulfur during processing such as cutting and polishing. That is.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems. As for the high-refractive-index (refractive index 1.64 or more) grade sulfur-containing plastic lens that is currently on the market, the gas generated when the edger for eyeglass lens processing is used to collect and process the gas is collected and analyzed. Very small amounts of mercaptans and sulfide derivatives having a simple alkyl group such as an ethyl group were detected, and off-flavors and odors generated during processing of the sulfur-containing plastic lens were determined to be derived from these. These are considered to be caused by partial cleavage of a simple alkylidene dithio structure derived from a polythiol monomer having a high sulfur content in the molecular structure forming the eyeglass lens resin at a high temperature during processing. Therefore, the molecular structure of polythiol was changed so that mercaptans and sulfide derivatives having simple alkyl groups such as these ethyl groups were not generated by thermal decomposition, and at the same time, the heat resistance of the resin was improved, and the decomposition was fundamentally reduced during thermal processing. As a result of intensive studies with the aim of incorporating molecular designs that are less susceptible to polythiol derivatives, a resin that can be obtained as a sulfur-containing monomer using only mercaptomethylbenzene-type polythiol derivatives and mercaptocarboxylic acid ester-type polythiol derivatives is processed. At times, they found that odor was not generated fundamentally, and completed the present invention.

That is, the present invention relates to a plastic lens comprising a sulfur-containing urethane resin obtained by polymerizing a polythiol and a polyisocyanate, wherein the compound represented by the following general formula (1) or (2) is used as the polythiol. A polyisocyanate containing xylylene diisocyanate is used as the polyisocyanate, using a compound represented by the formula (2) (Formula 2), and having a refractive index of 1.64 or more and an Abbe number of 30. The high-refractive-index plastic lens and polythiol described above are obtained by converting the compound represented by the general formula (1) to 4
0 to 80% by weight of the compound represented by the general formula (2)
The high-refractive-index plastic lens according to the present invention, wherein the polyisocyanate contains 50% by weight or more of xylylene diisocyanate, and the compound represented by the general formula (1). Is 1,2,4-tris (mercaptomethyl) benzene or the high-refractive-index plastic lens described therein, wherein the compound represented by the general formula (1) is 1,2,4-tris (mercaptomethyl) benzene, The compound represented by the general formula (2) is pentaerythritol tetrakis (2
-Mercaptoacetate) and / or pentaerythritol tetrakis (3-mercaptopropionate)
The high refractive index plastic lens described above.

[0010]

Embedded image (In the above formula, R represents a polyvalent group of an acyclic hydrocarbon having 2 to 9 carbon atoms, 1 represents 1 to 3, m represents 2 to 4, and n represents an integer of 2 to 4)

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The plastic lens of the present invention
The compound represented by the general formula (1) and the compound represented by the general formula (2) is used as a polythiol, and a polyisocyanate containing xylylene diisocyanate is used as a polyisocyanate. A plastic lens having a refractive index of 1.64 or more and an Abbe number of 30 or more, and which does not generate an odor or an odor peculiar to sulfur during processing such as cutting and polishing of the lens.

The polythiol represented by the general formula (1) used in the present invention includes o-xylylenedithiol,
m-xylylenedithiol, p-xylylenedithiol, 1,2,4-trismercaptomethylbenzene,
1,3,5-trismercaptomethylbenzene, 1,
2,3-trismercaptomethylbenzene, 1,2,2
3,4-tetrakismercaptomethylbenzene, 1,
2,4,5-tetrakismercaptomethylbenzene and the like. In order to achieve a refractive index of 1.64 or more, improve the heat resistance of the resin, and maintain a liquid state at room temperature so that the monomer can be easily handled, it is desirable that there are three mercaptomethyl groups per benzene ring. Therefore, the polythiol represented by the general formula (1) used in the present invention is more preferably a trismercaptomethylbenzene derivative, and from the viewpoint of heat resistance of a resin obtained by polymerization, 1,2,4-tris Mercaptomethylbenzene is particularly preferred.

Of these polythiols, o-xylylenedithiol, m-xylylenedithiol and p-xylylenedithiol are commercially available as reagents, and other compounds can be produced by known methods. Also, raw materials necessary for their synthesis are easily available. For example, 1,2,4,5-tetrakismercaptomethylbenzene can be obtained by reacting commercially available tetrakisbromomethylbenzene with thiourea, followed by hydrolysis in an aqueous alkaline solution. If the corresponding halomethylbenzene derivative is not available, the methylbenzene derivative is replaced with bromine or N-bromosuccinimide (N
BS), or the hydroxymethylbenzene derivative may be halogenated with phosphorus halide or the like.

As the compound represented by the general formula (2),
Diethylene glycol bis (2-mercaptoacetate), diethylene glycol bis (3-mercaptopropionate), ethylene glycol bis (2-mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), trimethylolpropane tris (3-mercapto Propionate), trimethylolpropane tris (2-mercaptoacetate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate) and the like. It is preferable to use pentaerythritol tetrakis (2-mercaptoacetate) or pentaerythritol tetrakis (3-mercaptopropionate) in consideration of the refractive index and heat resistance of the obtained resin, availability and price. Pentaerythritol tetrakis (3-mercaptopropionate) is generally commercially available, and may contain pentaerythritol tris (2-mercaptoacetate), pentaerythritolbis (2-mercaptoacetate) or the like as an impurity. The same applies to pentaerythritol tetrakis (2-mercaptoacetate).

The present invention is characterized in that the compound represented by the general formula (1) and the compound represented by the general formula (2) are used in combination, and the Abbe number is improved by using both compounds in combination. As a result, the optical performance of the resin can be adjusted to a desired value. In addition, the dyeability can be improved while keeping the heat resistance moderate. The ratio of the compound represented by the general formula (1) and the compound represented by the general formula (2) is preferably 4
0 to 80% by weight: 60 to 20% by weight.

The polyisocyanate used in the present invention is o
Polyisocyanate containing xylylene diisocyanate such as xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethyl-p-xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate And
Preferably, xylylene diisocyanate is 50% by weight.
It is a polyisocyanate contained above. Examples of the polyisocyanate used together with xylylene diisocyanate include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, and these. Chlorinated, brominated, methylated or ethylated, isophorone diisocyanate, norbornene diisocyanate and the like. These can be used alone or as a mixture of two or more kinds together with xylylene diisocyanate. The polyisocyanate used in the present invention, considering the refractive index and availability, etc.,
More preferred is m-xylylene diisocyanate or a mixture of m-xylylene diisocyanate and norbornene diisocyanate and / or hexamethylene diisocyanate.

The sulfur-containing polyurethane lens of the present invention comprises:
Usually, it is obtained by cast polymerization. Specifically, the monomer mixture and the above-mentioned compound used in the present invention are mixed well, and if necessary, after defoaming by an appropriate method, the mixture is poured into a mold and heated. Polymerize. At this time, a known release treatment may be applied to the mold in order to facilitate release after polymerization. Further, in order to adjust the reaction rate to a desired one, a known catalyst may be appropriately added. The polymerization temperature and the polymerization time are appropriately determined depending on the combination of the monomers to be used and the kind of the compound to be added. For example, the polymerization can be performed at 20 to 200 ° C. for 0.5 to 100 hours. Also, if necessary, as in the known molding method, various kinds of internal release agents, chain extenders, cross-linking agents, light stabilizers, ultraviolet absorbers, antioxidants, oil-soluble dyes, fillers, etc. Substances may be added. Further, the sulfur-containing plastic lens of the present invention may have a surface polished surface, if necessary, for improving anti-reflection, imparting high hardness, improving abrasion resistance, improving chemical resistance, imparting anti-fogging property or providing fashionability. Physical or chemical treatments such as antistatic treatment, hard coat treatment, anti-reflection coat treatment, dyeing treatment, and net light treatment.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to 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 a Pulfrich refractometer
Was measured.・ Appearance: Observed visually.・ Heat resistance: Thermomechanical analyzer TAS300
(Manufactured by Rigaku Denki Co., Ltd.), 5 g of weight was applied to the test piece, and the temperature was 2.5 ° 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.
ML-Blue was immersed at 95 ° C. for 5 minutes in a dyeing tank prepared in a 5 g / L aqueous solution 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). -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 23.7 parts by weight of m-xylylene diisocyanate, 9.6 parts by weight of pentaerythritol tetrakis (2-mercaptoacetate), 11.7 parts by weight of 1,2,4-tris (mercaptomethyl) benzene , And 0.01% by weight of dimethyltin dichloride (the same applies to the total amount of the mixture, the same applies hereinafter), and after sufficiently defoaming, the mixture was poured into a glass mold subjected to a mold release treatment. From 30 ℃
The polymerization was carried out while gradually raising the temperature to 120 ° C. over 22 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained lens was colorless and transparent, excellent in impact resistance, had a refractive index of 1.64, an Abbe number of 32, a thermal deformation start temperature of 127 ° C., and did not have any odor. The transmittance after staining is 33% in ML-Yellow,
It was 37% for ML-Red and 37% for ML-Blue, and the overall evaluation of staining was (（). When this lens was cut and polished with an edger for processing eyeglass lenses, the irritating odor peculiar to sulfur was hardly generated, and the operator did not feel discomfort.

Example 2 28.1 parts by weight of m-xylylene diisocyanate, 6.0 parts by weight of pentaerythritol tetrakis (3-mercaptopropionate), 18 parts by weight of 1,2,4-tris (mercaptomethyl) benzene , And 0.01% by weight of dimethyltin dichloride were thoroughly mixed and sufficiently degassed, and then the mixture was poured into a glass mold subjected to a release treatment. The polymerization was carried out while gradually increasing the temperature from 30 ° C. to 120 ° C. over 22 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained lens was colorless and transparent, excellent in impact resistance, had a refractive index of 1.65, an Abbe number of 30, a thermal deformation onset temperature of 133 ° C., and did not feel any odor. The transmittance after staining was ML-Y
38% for ELL, 45% for ML-Red, ML-B
lue was 49%, and the overall evaluation of staining was (性 の). When this lens was cut and polished with an edger for processing eyeglass lenses, the irritating odor peculiar to sulfur was hardly generated, and the operator did not feel discomfort.

Example 3 21.1 parts by weight of m-xylylene diisocyanate, 6.6 parts by weight of pentaerythritol tetrakis (3-thiopropionate), 12.3 of 1,2,4-tris (mercaptomethyl) benzene Parts by weight and 0.01% by weight of dimethyltin dichloride were mixed well, and after sufficient defoaming, the mixture was poured into a glass mold subjected to a release treatment. The polymerization was carried out while gradually increasing the temperature from 30 ° C. to 120 ° C. over 22 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained lens was colorless and transparent, excellent in impact resistance, had a refractive index of 1.64, an Abbe number of 32, a thermal deformation onset temperature of 128 ° C., and did not have any odor. The transmittance after staining was ML-Y
35% for ELL, 39% for ML-Red, ML-B
lue was 42%, and the overall evaluation of staining was (性 の). When this lens was cut and polished with an edger for processing eyeglass lenses, the irritating odor peculiar to sulfur was hardly generated, and the operator did not feel discomfort.

Comparative Example 1 39.1 parts of m-xylylene diisocyanate, 1,2,2
After mixing 30.0 parts of 4-tris (mercaptomethyl) benzene to make a uniform liquid, sufficiently defoaming, the mixture was poured into a mold including a glass mold and a gasket subjected to a release treatment. 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 was colorless and transparent, had a refractive index of 1.67 and an Abbe number of 28, and had a thermal deformation onset temperature of 132 ° C. The transmittance after staining was 61% for ML-Yellow and 77% for ML-Red.
% And 78% in ML-Blue, and the overall evaluation of the staining properties was (x). When this lens was cut and polished with an edger for processing eyeglass lenses, the irritating odor peculiar to sulfur was hardly generated, and the operator did not feel discomfort. This resin obtained by polymerizing only 1,2,4-trismercaptomethylbenzene and m-xylylene diisocyanate at a functional group equivalent ratio of 1: 1 has an Abbe number of 28.
It was low. This Abbe number is described in catalogs and the like as one of the indexes indicating the chromatic aberration of the spectacle lens,
The impression that the Abbe number is 20 or less than 30, and the 30 or more than 30 lenses is given to the customer,
The product value has a great difference that can be said to be completely different. Even if it is a resin for an ultra-high refractive index lens whose refractive index exceeds 1.64, if it cannot secure Abbe number of 30 or more, it is the highest grade Is not recognized as a spectacle lens. Further, this lens had a high heat deformation starting temperature of 132 ° C. The heat deformation initiation temperature and the dyeability are generally opposite to each other, and it is well known that if the temperature is high, the dyeability is poor. Therefore, this lens cannot be dyed according to customer's preference without advanced dyeing technology, and is not preferable.

Comparative Example 2 m-xylylene diisocyanate 65.4 parts, 1,2-
60.1 parts of bis [(2-mercaptoethyl) thio] -3-mercaptopropane, dibutyltin dilaurate 0.
1% by weight was mixed to form a uniform liquid, sufficiently defoamed, and then poured into a mold including a glass mold and a gasket subjected to a release treatment. While gradually raising the temperature from 40 ° C. to 120 ° C., the composition was cured by heating for 20 hours. After 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 of 1.6.
6, Abbe number was 33, and thermal deformation onset temperature was 84 ° 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 (）). When this lens was cut and polished with an edger for processing eyeglass lenses, an irritating odor peculiar to sulfur was clearly felt.

[0024]

According to the present invention, the combined use of the compound represented by the general formula (1) and the compound represented by the general formula (2) allows the obtained sulfur-containing urethane resin to have a high refractive index and an Abbe number. An object of the present invention is to provide a plastic lens which has improved dyeing properties while maintaining the preferable range, and which does not emit odor during processing such as cutting and polishing, and which has extremely excellent performance.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Imai 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Kenichi Fujii 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Inside the corporation

Claims (5)

[Claims] 1. A plastic lens comprising a sulfur-containing urethane resin obtained by polymerizing a polythiol and a polyisocyanate, wherein the polythiol is represented by the following general formula (1):
A refractive index characterized by using a compound represented by the formula (1) and a compound represented by the following formula (2) (formula 1), and using a polyisocyanate containing xylylene diisocyanate as the polyisocyanate. Is 1.64 or more,
A high refractive index plastic lens having an Abbe number of 30 or more. Embedded image (In the above formula, R represents a polyvalent group of an acyclic hydrocarbon having 2 to 9 carbon atoms, 1 represents 1 to 3, m represents 2 to 4, and n represents an integer of 2 to 4) 2. The polythiol according to claim 1, wherein the polythiol contains 40 to 80% by weight of the compound represented by the general formula (1) and 20 to 60% by weight of the compound represented by the general formula (2). High refractive index plastic lens. 3. The polyisocyanate contains at least 50% by weight of xylylene diisocyanate.
The high refractive index plastic lens described. 4. The compound represented by the general formula (1) is
The high refractive index plastic lens according to claim 2 or 3, which is 2,4-tris (mercaptomethyl) benzene. 5. The compound represented by the general formula (1) is 1,
2,4-tris (mercaptomethyl) benzene,
The high-refractive index plastic lens according to claim 3, wherein the compound represented by the general formula (2) is pentaerythritol tetrakis (2-mercaptoacetate) and / or pentaerythritol tetrakis (3-mercaptopropionate).