JPH07118989B2 - Polyurethane lens manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyurethane lens. The polyurethane lens obtained by the method of the present invention is used as various optical lenses such as eyeglass lenses and camera lenses.

[Prior Art] In recent years, demand for plastic lenses for eyeglasses has been increasing in Japan and overseas. As the plastic lens materials used in recent years, those obtained by casting polymerization of diethylene glycol bisallyl carbonate (hereinafter abbreviated as DAC) are generally used, and those obtained by injection molding of polymethylmethacrylate, polystyrene, polycarbonate, etc. Used in part.

The characteristics of DAC resin lenses are that they are lighter than glass, less likely to break, and have excellent dyeability, and they can meet the fashionable needs of combining color lenses with today's large frames.

However, DAC resin has a refractive index (hereinafter abbreviated as N _D )
Since it is 1.500, which is lower than N _D 1.523 of glass, the thickness of the lens is large, and it is not so favored by users who particularly need a strong lens.

As an attempt to improve such defects of DAC resin lens,
Many proposals have been made. For example, JP-A-60-217301
In the publication, a copolymer of polyisocyanate, polyol and aromatic vinyl compound is proposed. The copolymer obtained by this method has a high N _D of 1.60 or more, and the lens thickness can be reduced, but the light dispersion (hereinafter, ν _D
Is about 30) and the color dispersion is conspicuous, and the range of use is very limited for a spectacle lens. Further, it is difficult to control the reaction between the polyisocyanate and the polyol, and therefore it is necessary to reduce the isocyanate component and the polyol component contained in the monomer mixture. However, it is difficult to obtain good impact resistance originally possessed by the urethane bond.

Further, JP-A-59-164501 proposes a copolymer of a halogen-containing aromatic vinyl compound. In the case of this copolymer, N _D is as high as 1.60 to 1.64 and is an effective means for suppressing the thickness of the lens. On the other hand, ν _D is only about 30 and its utility value as an eyeglass lens is low. It is also said to have poor impact resistance and low dyeability.

Further, JP-A-60-217229 discloses a copolymer of polyisocyanate and S atom-containing polyol.
-199016 proposes a copolymer of polyisocyanate and polyol. Since these polyurethane lenses have a high N _D of 1.56 to 1.64 and a low specific gravity of 1.22 to 1.44, they are particularly suitable as thin and light eyeglass lenses. Also, these polyurethane lenses are originally excellent in impact resistance and dyeability. However, when producing these polyurethane lenses by cast polymerization, the glass surface or metal mold for casting is coated with silicone or a fluorine-based releasing agent to improve the mold releasability of the lens. There is a problem that the mold release agent migrates to the mold, causing color unevenness during dyeing and film baldness of the coating film, and the mold release process is required even in the process, and the mold is washed for a long time after use. However, this is not the preferred method.

In order to eliminate the drawbacks of the above-mentioned mold release method of applying a mold release agent to the mold, it is also attempted to add the mold release agent to the monomer mixture without coating the mold, and then perform cast polymerization. However,
When a silicone or fluorine-based release agent is added to a monomer mixture containing a polyisocyanate and a polyol, the amount of the release agent contacting the inner surface of the mold is extremely small compared to the case of applying the release agent, As a result, the obtained polyurethane lens cannot be smoothly released from the mold. If the amount of the mold release agent added to the monomer is increased, the mold releasability is improved, but a large amount of the mold release agent causes cloudiness in the lens, or the lens and the mold are separated from each other during the polymerization. It occurs and it is not possible to obtain a lens with commercial value.

[Problems to be Solved by the Invention] As described above, the conventional polyurethane lens has an N _D of 1.56 to 1.64.
It has a high specific gravity and a low specific gravity of 1.22 to 1.44, so it is thin and light, and because it is originally excellent in impact resistance and dyeability, it is suitable as an optical lens such as an eyeglass lens. When obtained by cast polymerization, the releasability of the obtained lens from the molding die was poor, and various means for improving releasability have been tried for that purpose, but existing silicone and fluorine-based mold release agents are molded. In the method of applying to the mold, problems such as color unevenness at the time of dyeing due to transfer of the release agent to the lens surface, film baldness of the coating film, etc. occur, and in the method of adding the release agent to the monomer mixture, However, problems such as poor mold releasability, cloudiness of the lens, and mold release between the lens and the mold have occurred.

Therefore, an object of the present invention is to produce a novel polyurethane lens which is excellent in mold releasability of a lens after cast polymerization, and is capable of obtaining a polyurethane lens free from defects such as color unevenness during dyeing and film baldness of a coating film. To provide a method.

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, have shown that a monomer mixture for producing a polyurethane lens has a general formula (In the formula, R ₁ and R ₂ are the same or different, and are an alkyl group having 1 to 8 carbon atoms).
It has been found that, when cast polymerization is carried out, the obtained polyurethane lens substrate can be easily released from a mold such as a glass mold or a metal mold, as in the case where a conventional DAC resin is obtained by cast polymerization. Further, according to the method for producing a polyurethane lens of the present invention using the above-mentioned phosphate ester releasing agent, the present inventors apply a conventionally known silicone or fluorine-based releasing agent to a molding die or add it to a monomer mixture. It was found that, unlike the method described above, problems such as clouding of the lens and mold release during polymerization do not occur. Further, the present inventors, when subjected to a treatment such as dyeing treatment, hard coating treatment, antireflection coating treatment, etc., on the polyurethane lens substrate obtained by the above-mentioned cast polymerization, there are problems such as uneven dyeing and film baldness of the coating film. It has been found that a polyurethane lens is obtained which does not occur.

Accordingly, the present invention provides a monomer mixture containing polyisocyanate and polythiol having the general formula (Wherein R ₁ and R ₂ are the same or different and are alkyl groups having 1 to 8 carbon atoms), and then cast polymerized in a plastic lens manufacturing mold to produce polyurethane. A method for producing a polyurethane lens is characterized in that a lens substrate is produced, and then at least one treatment selected from dyeing treatment, hard coating treatment and antireflection coating treatment is applied.

Hereinafter, the present invention will be described in detail.

In the present invention, the phosphoric acid ester added to the monomer mixture and used as the mold releasing agent has the general formula as described above. (In the formula, R ₁ and R ₂ are the same or different and are alkyl groups having 1 to 8 carbon atoms).

In the phosphoric acid ester of the above general formula (I), R ₁ and R ₂
Is limited to an alkyl group having 1 to 8 carbon atoms because the obtained polyurethane lens becomes cloudy when a phosphate ester having a prime number of more than 8 is used.

Further, in the phosphoric acid ester of the general formula (I), R ₁ and R ₂ are the same or different alkyl groups, but considering availability, a phosphoric acid ester in which R ₁ and R ₂ are the same alkyl group is used. It is preferably used.

Examples of such a phosphoric acid ester include dimethyl phosphate,
Diethyl phosphate, dipropyl phosphate, dibutyl phosphate,
Examples include dipentyl phosphate, dihexyl phosphate, diheptyl phosphate and dioctyl phosphate.

Further, as described above, the phosphoric acid ester of the general formula (I) has one hydroxyl group in the molecule, but in the present invention, the phosphoric acid ester limited to one phosphoric acid ester is two hydroxyl groups in the molecule. In the case of a phosphate ester having a hydroxyl group as described above, it is easy to react with polyisocyanate, foams during polymerization or produces an opaque substance during preparation, and conversely, in the case of a phosphate ester having no hydroxyl group in the molecule, This is because the obtained polyurethane lens substrate is fused to the mold and cannot be released.

Also the general formula (In the formula, R represents an alkyl group and n represents an integer of 0 to 3) In the case of the phosphite ester, a urethane lens substrate is irrespective of the addition amount of the phosphite ester and the molecular structure. Cannot be released from the mold.

The addition amount of the phosphoric acid ester of the general formula (I) is preferably 0.01 to 20% by weight, particularly preferably 0.02 to 5% by weight, based on the total amount of polyisocyanate and polythiol. When the addition amount of the phosphate ester is less than 0.01% by weight, it is difficult to release the lens substrate after polymerization from the glass mold or the metal mold, and when the addition amount of the phosphate ester exceeds 20% by weight. This is because cloudiness of the lens substrate or foaming or gelation during preparation may occur.

However, by considering other polymerization conditions etc.,
Even if the addition amount of the phosphoric acid ester is less than 0.01% by weight or exceeds 20% by weight, there is a possibility that the polymerization can be performed without any problem and the obtained lens substrate can be successfully released from the molding die. , The above-mentioned phosphate ester addition amount range
0.01 to 20% by weight is not critical.

The polyisocyanate used as a monomer for producing the polyurethane lens substrate in the present invention is not particularly limited, but tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, naphthylene diisocyanate, tolylene diisocyanate, hexamethylene. Diisocyanate, isophorone diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatophenyl) thiophosphate, trans-cyclohexane 1,4-diisocyanate, p-
Phenylene diisocyanate, tetramethylene diisocyanate, 1,6,11-undecane triisocyanate, 1,
Polyisocyanate compounds such as 8-diisocyanate-4-isocyanate methyl octane, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate and bicycloheptane triisocyanate, and allophanate modified products, buret modified products and isocyanurates of these compounds Examples thereof include a modified product, an adduct modified product with a polyol or a polythiol, and the like, which may be used alone or may be used as a mixture of two or more kinds as necessary.
Other known isocyanate compounds can be used, but the isocyanate compound as the main component must be bifunctional or higher. A halogen atom such as Cl or Br may be introduced into a known aromatic isocyanate compound. Particularly preferred isocyanate compound, xylene diisocyanate, isophorone diisocyanate,
A non-yellowing type isocyanate compound represented by hexamethylene diisocyanate can be given.

In the present invention, the polythiol used for the reaction with the polyisocyanate for producing the polyurethane lens substrate is not particularly limited, and known polythiols can be used. For example, ethanedithiol, propanedithiol, propanetrithiol, butanedithiol, pentanedithiol, hexanedithiol, heptanedithiol, octanedithiol, cyclohexanedithiol, cycloheptanedithiol, 2,5-dichlorobenzene-1,3-dithiol, pentaerythritol tetrakis Examples thereof include 3-mercaptopropionate and pentaerythritol tetrakisthioglycolate, with pentaerythritol derivatives being particularly preferred.

As another polythiol, the general formula (II) (In the formula, R ₁ , R ₂ and R ₃ are the same or different alkyl groups having 1 to 8 carbon atoms) and a polythiol having a triazine ring can be used. As the polythiol having such a triazine ring, tris (2-mercaptoethyl) isocyanurate, tris (3-mercapto-n-propyl) isocyanurate, tris (2-methyl-3-mercapto-n-propyl) isocyanurate, Tris (mercaptomethyl) isocyanurate, Tris (2-hydroxyethyl)
Examples include mercaptopropionic acid ester of isocyanuric acid, mercaptoacetic acid ester of tris (2-hydroxyethyl) isocyanuric acid, mercaptopropionic acid ester of tris (hydroxymethyl) isocyanuric acid, and mercaptoacetic acid ester of tris (hydroxymethyl) isocyanuric acid. .

The mixing ratio of polyisocyanate and polythiol is NCO / SH
The (molar ratio) is preferably in the range of 0.5 to 1.5, particularly preferably 0.8 to 1.2. When the NCO / SH ratio is out of the range of 0.5 to 1.5, the degree of polymerization is remarkably lowered, and important physical properties such as heat resistance, impact resistance, surface hardness and surface accuracy are deteriorated.

The polymerization catalyst used is dibutyltin dilaurate,
A tin compound such as dibutyltin dimaleate is preferably used. Amine-based catalysts tend to foam and are not suitable as catalysts for lens molding. When a tin compound is used as a catalyst, the addition amount thereof is preferably 0.01 to 0.8% by weight, and particularly preferably 0.02 to 0.2% by weight, based on the total amount of polyisocyanate and polythiol. It is desirable to determine the addition amount of the catalyst within the range depending on the reactivity and the catalytic activity of the monomer used. The amount of tin catalyst added is 0.
When it is less than 01% by weight, the polymerization degree is remarkably lowered, and important physical properties such as heat resistance, impact resistance, surface hardness, and surface accuracy are lowered, and when it exceeds 0.8% by weight, foaming is liable to occur. It is not preferable because the pot life becomes extremely short.

As the polymerization temperature, the initial temperature is preferably in the range of 5 to 40 ° C, and it is preferable to raise the temperature to 100 to 130 ° C over 10 to 70 hours. If the initial temperature is lower than 5 ° C., the polymerization time becomes unnecessarily long, and if the initial temperature is higher than 40 ° C., the obtained lens substrate tends to be optically nonuniform. Further, if the final temperature is less than 100 ° C, unreacted substances are likely to remain and the degree of polymerization is lowered to deteriorate various physical properties.

Known additives can be added to the monomer mixture containing polyisocyanate and polythiol, if necessary.
Examples thereof include light stabilizers, ultraviolet absorbers, antioxidants, antistatic agents, defoamers and the like. Further, copolymerization with a radically polymerizable monomer is also possible for the purpose of improving physical properties. In some cases, a small amount of hydroxyl group-containing monomer can be used,
In that case, NCO / SH + OH (molar ratio) must be in the range of 0.5 to 1.5.

In the present invention, at least 1 selected from the dyeing treatment, the silicon-containing or acrylic hard coat treatment, and the antireflection coat treatment with an inorganic or organic substance is applied to the polyurethane lens substrate obtained by the above-mentioned cast polymerization.
By subjecting the seeds to the treatment, the desired polyurethane lens is obtained. Note that polishing treatment, antifogging treatment, and water / oil repellent treatment may be additionally performed.

[Examples] The present invention will be further described with reference to Examples.

Example 1 m-xylene diisocyanate (mXDI) 100 g pentaerythritol tetrakis 3-mercaptopropionate (PETMP) 142 g di-n-butyl phosphate (DBP) 6.05 g * (2.5% by weight based on mXDI + PETMP) dibutyltin dilauric acid 0.24 g 2 (2'-hydroxy-5'-t-octylphenyl)
Benzotriazole 0.48 g The above mixture was stirred at room temperature for 30 minutes and degassed at 1 mmHg for 60 minutes, and then placed in a mold composed of a polyethylene gasket and a glass mold at 25 ° C for 5 hours, 40 ° C for 5 hours, After polymerizing at 60 ° C. for 7 hours, at 80 ° C. for 3 hours, and at 120 ° C. for 2 hours, the polyurethane lens substrate was taken out from the mold.
The obtained lens substrate has an N _D of 1.592, a ν _D of 36, and a specific gravity of 1.3.
It was 5 and transparent. The mold releasability was good, and the lens and the mold were not damaged. Next, on this lens substrate,
Dyeing treatment, silicon hard coat treatment, and antireflection coat treatment were performed respectively. The lens thus obtained has a center thickness of 1.6 mm, has no color unevenness after dyeing, has no film baldness on the coating film, and has a silicone hard coat or an antireflection coating made of an inorganic substance, which is a US FDA standard. It had impact resistance that passed the requirements (see Table 1 for details).
See).

Example 2 The amount of DBP added was 2.8 g (1.2% by weight with respect to mDXI + PETMP).
The same procedure as in Example 1 was carried out except for the above, and as shown in Table 1, an excellent polyurethane lens similar to that in Example 1 was obtained.

Example 3 Instead of 100 g of mXDI, isophorone diisocyanate (IPD
I) The same procedure as in Example 1 was carried out except that 115 g was used and the amount of DBP added was 2.8 g (1.1% by weight with respect to IPDI + PETMP). Got the lens.

Example 4 Example except that 95 g of mXDI and 5 g of tolylene diisocyanate (TDI) were used instead of 100 g of mXDI, the amount of PETMP was 132 g, and the amount of DBP added was 1.4 g (0.6% by weight based on mXDI + TDI + PETMP). The same procedure as 1 is performed, and as shown in Table 1,
An excellent polyurethane lens similar to that of Example 1 was obtained.

Example 5 m-xylene diisocyanate (mXDI) 100 g tris (3-mercapto-n-propyl) isocyanurate (TMPIC) 124 g di-n-butyl phosphate (DBP) 5.6 g * (* 2.5% by weight based on mXDI + PETMP) dibutyltin Dilauric acid 0.2g 2 (2'-hydroxy-5'-t-octylphenyl)
Benzotriazole 0.5 g The above mixture was stirred at room temperature for 30 minutes and degassed at 1 mmHg for 60 minutes in a mold composed of polyethylene gasket and glass mold at 25 ° C for 5 hours, 40 ° C for 5 hours, After polymerizing at 60 ℃ for 7 hours, 80 ℃ for 3 hours, and 120 ℃ for 2 hours,
The polyurethane lens substrate was taken out of the mold. The obtained lens substrate was transparent with N _D of 1.61, ν _D of 35 and specific gravity of 1.35. The mold releasability was good, and the lens and the mold were not damaged. Next, this lens substrate was subjected to dyeing treatment, silicon hard coat treatment, and antireflection coat treatment, respectively. The lens obtained in this way has a center thickness of 1.8 mm, no color unevenness after dyeing, no film baldness of the coating film, and a silicone hard coat and an antireflection coating made of an inorganic substance are in compliance with US FDA standards. It had an impact resistance that passed (see Table 1 for details).

Example 6 Tolylene diisocyanate (TDI) 1 instead of 100 g mXDI
The amount of TMPIC (tris (3-mercapto-n-propyl) isocyanurate) was adjusted to 140 g and the amount of DBP was adjusted to 6.0 g.
The same procedure as in Example 5 was carried out except that the amount was changed to g (2.5% by weight based on TDI + TMPIC), and as shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 7 Using TDI 50g and mXDI 50g instead of mXDI 100g, TMPIC
(Tris (3-mercapto-n-propyl) isocyanurate) was set to 135 g, and DBP was set to 5.9 g (2.5% by weight based on TDI + TMPIC). As shown, an excellent polyurethane lens similar to that of Example 5 was obtained.

Example 8 Pentaerythritol tetrakis-3-mercaptopropionate (PETMP) 97 g and TMPIC were used instead of TMPIC (tris (3-mercapto-n-propyl) isocyanurate) 124 g.
The same procedure as in Example 5 was carried out except that 31 g was used and the amount of DBP was 5.7 g (2.5% by weight based on mXDI + PETMP + TMPIC).
As shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 9 Instead of 124 g of TMPIC (tris (3-mercapto-n-propyl) isocyanurate), 65 g of PETMP (pentaerythritol tetrakis-3-mercaptopropionate) and TMPIC 6 were used.
The same procedure as in Example 5 was performed except that 2 g was used and the amount of DBP was 5.7 g (2.5% by weight with respect to mXDI + PETMP + TMPIC).
As shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 10 Instead of 124 g of TMPIC (tris (3-mercapto-n-propyl) isocyanurate), 32 g of PETMP (pentaerythritol tetrakis-3-mercaptopropionate) and TMPIC 9
The same procedure as in Example 5 was carried out except that 3 g and TMPIC 93 g were used, and as shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 11 TDI 75 g and mXDI 25 g were used in place of mXDI 100 g, TMPIC
The same procedure as in Example 5 was repeated except that the amount of (tris (3-mercapto-n-propyl) isocyanurate) was changed to 126 g,
As shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 12 Using TDI 25g and mXDI 75g instead of mXDI 100g, TMPIC
(Tris (3-mercapto-n-propyl) isocyanurate) amount to 132g, DBP amount 5.8g (mXDI + TDI + TMPI
The same procedure as in Example 5 was carried out except that the content was 2.5% by weight based on C), and as shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 13 The amount of DBP was 1.8 g (mxDI + TMPIC (tris (3-mercapto-
0.8% by weight based on n-propyl) isocyanurate)
Except for the above, the same procedure as in Example 5 was carried out, and as shown in Table 1, an excellent polyurethane lens similar to that in Example 5 was obtained.

Example 14 TDI 100 g was used instead of mXDI 100 g, and TMPIC (Tris (3-
The amount of mercapto-n-propyl) isocyanurate) is 14
The procedure was the same as in Example 5 except that the amount of DBP was 0 g and the amount of DBP was 1.9 g (0.8% by weight based on TDI + TMPIC), and as shown in Table 1, an excellent polyurethane lens similar to that of Example 5 was obtained. .

Example 15 Using 100 g of TDI instead of 100 g of mXDI, TMPIC (Tris (3-
The amount of mercapto-n-propyl) isocyanurate) is 14
The procedure was the same as in Example 5 except that the amount of DBP was 0 g and the amount of DBP was 3.6 g (1.5% by weight based on TDI + TMPIC), and as shown in Table 1, an excellent polyurethane lens similar to that of Example 5 was obtained. .

Comparative Examples 1 and 2 As the phosphate ester, tributyl phosphate (TBP) (Comparative Example 1) and monobutyl phosphate (MBP) (Comparative Example 2) which are not included in the phosphate ester of the general formula (I) of the present invention are used. A polyurethane lens was obtained in the same manner as in Example 1 except for the above, but as shown in Table 1, in Comparative Example 1, lens releasability was not obtained, and in Comparative Example 2, lens fogging and Precipitation of opaque material was observed.

Comparative Example 3 As the phosphate ester, a mixture of isodecyl phosphate and diisodecyl phosphate, which is a phosphate ester having an alkyl group having 10 carbon atoms, which is not included in the phosphate ester of the general formula (I) of the present invention (Dahachi Chemical Industry Co., Ltd. A polyurethane lens was obtained in the same manner as in Example 1 except that AP-10 manufactured by Co., Ltd. was used.
As shown in Table 1, this lens was inferior in transparency and was cloudy.

Comparative Example 4 A polyurethane lens was obtained in the same manner as in Example 1 except that dibutyl phosphite (DBP-1 manufactured by Daihachi Chemical Co., Ltd.) was used instead of the phosphoric acid ester of the present invention. As shown in, the releasability of the lens was not obtained.

Comparative Examples 5 and 6 The same procedure as in Example 1 was carried out except that a conventional release agent, Shin-Etsu Silicon Co., Ltd. silicon release agent L-722 was used.
A polyurethane lens was obtained, but in the case of Comparative Example 5 in which the addition amount of the silicon-based release agent was small, the mold releasability of the lens was not obtained, and in the case of Comparative Example 6 in which the addition amount of the silicon-based release agent was large. Although releasability was obtained, the lens was clouded and the transparency was poor.

Comparative Examples 7 and 8 Conventional silicon-based mold release agent YSR-6209 (manufactured by Toshiba Silicon Co., Ltd.) and fluorine-based mold release agent MS-443 (manufactured by Daikin Industries, Ltd.) were applied to a glass mold for casting. Except for the above, the same procedure as in Example 1 was performed. That is, a 5% solution of YSR-6209 in toluene and a 5% solution of MS-443 in Freon were prepared, and a glass mold for casting was immersed in each solution, followed by heating at 250 ° C for 3 hours.
What was heated for 0 minutes was used as a casting mold.

As shown in Table 1, in the case of YSR-6209 (Comparative Example 7), the mold release property is good, but the color unevenness after dyeing is remarkable, and it is difficult to remove the mold release agent remaining in the glass mold. There was a problem with sex. In the case of MS-443 (Comparative Example 8), mold release occurred during polymerization, which was unsuitable as a lens. Further, color unevenness after dyeing and film baldness of the coat film were generated, and it was difficult to remove the release agent remaining in the glass mold like YSR-6209.

Table Description 1. Symbol mXDI m-Xylene Diisocyanate IPDI Isophorone Diisocyanate TDI Tolylene Diisocyanate PETMP Pentaerythritol Tetrakismercaptopropionate TMPIC Tris (3-mercapto-n-propyl) isocyanurate TBP Tributyl Phosphate MBP Monobutyl Phosphate AP-10 Daihachi Chemical Co., Ltd. isodecyl phosphate-diisodecyl phosphate mixture DBP-1 Daihachi Chemical Co., Ltd. dibutyl phosphite L-722 Shin-Etsu Silicon Co., Ltd. silicon release agent YSR-6209 Toshiba Silicon type release agent made by Silicon Co., Ltd. MS-443 Fluorine type release agent made by Daikin Industries, Ltd. 2. Measurement method (1) Releasability was measured when the obtained lens was peeled off from the glass mold. And, those that can be released without damaging the glass mold are passed (○), and those that are not released are rejected (x). .

(2) Regarding the color unevenness after dyeing, the one having no unevenness in the visual inspection of the dyed lens was passed (◯), and the one having unevenness was rejected (x).

(3) For the film baldness, use a knife to make a 1 mm-width grid on the lens obtained by applying a silicon hard coat and an inorganic anti-reflection coat, and use Nichiban cellophane tape to vigorously apply the tape. If the coating film adhered even after peeling, it was judged as pass (◯), and if not, it was judged as fail (x).

(4) As for transparency, the obtained lens was visually observed under a fluorescent lamp in a dark place, and when there was no fogging of the lens and deposition of an opaque substance, it was passed (○), and when there was some, it was rejected (×). ).

(5) Impact resistance was evaluated according to the FDA standard, and those that passed were marked with a circle, and those that did not were rated as a failure (x).

(6) N _D and ν _D were measured using an Abbe refractometer.

In Table 1, in the columns of color unevenness, film baldness, transparency, impact resistance, N _D and ν _D , no evaluation is given to indicate that measurement is impossible or measurement is not performed.

[Effects of the Invention] As described above, according to the method for producing a polyurethane lens of the present invention, the obtained lens substrate has a good mold releasability from the molding die, uneven color after dyeing, and a coating film. Does not cause baldness or fogging of the lens and has good impact resistance.
There is an advantage that a lens having high N _D and ν _D values can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Sugimura 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Hoya Co., Ltd. (56) Reference JP 61-197639 (JP, A) JP Sho 62-50336 (JP, A)

Claims (1)

[Claims] 1. A monomer mixture containing polyisocyanate and polythiol has the general formula (Wherein R ₁ and R ₂ are the same or different and are alkyl groups having 1 to 8 carbon atoms), and then cast polymerized in a plastic lens manufacturing mold to produce polyurethane. A method for producing a polyurethane lens, which comprises producing a lens substrate and then subjecting it to at least one treatment selected from a dyeing treatment, a hard coat treatment and an antireflection coat treatment.