JP2012082415A - Method for producing plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which a plastic lens having excellent transparency without turbidity and tarnish can be produced without passing a complicated step even when an aromatic polyisocyanate compound is used as a raw material.SOLUTION: The method for producing the plastic lens by mixing and reacting raw materials containing at least one of polyisocyanate compound and at least one of polythiol compound includes using at least one of aromatic polyisocyanate compound as the polyisocyanate compound, and filtering and purifying the aromatic polyisocyanate compound before being mixed with the polythiol compound.

Description

  The present invention relates to a method for manufacturing a plastic lens. More specifically, the present invention relates to a method for producing a plastic lens having excellent transparency without turbidity or spiders.

Plastics are used in various lenses such as eyeglasses because they are lighter than glass, have excellent processability, are hard to break, and have high safety.
However, although the plastic lens has the advantages as described above, the lens may become cloudy or spidery due to impurities generated in the manufacturing process, and various studies have been conducted to obtain a lens with excellent transparency. I came.
For example, it is known that by using a compound having an epithio group and a polyisocyanate compound or a polythiol compound as raw materials and polymerizing them, a plastic lens for eyeglasses having a high refractive index, a high Abbe number and excellent transparency can be obtained. (For example, Patent Document 1).

JP 2001-330701 A

On the other hand, when an aromatic polyisocyanate compound is used as a raw material, particulate impurities may be deposited on the entire lens, which may cause clouding and turbidity of the lens. An example using an aromatic polyisocyanate compound as a compound is not disclosed.
Since the above-mentioned particulate impurities are not confirmed in the raw material mixture before the raw material containing the aromatic polyisocyanate compound is reacted, there is a problem that it is difficult to remove the impurities in the lens manufacturing process. Therefore, it may not be preferable to use an aromatic polyisocyanate compound as a raw material in the production of various lenses.

  In view of the above problems, the present invention is a method capable of producing a plastic lens having excellent transparency without turbidity and spiders without complicated steps even when an aromatic polyisocyanate compound is used as a raw material. Is intended to provide.

  As a result of intensive studies in order to achieve the above object, the present inventor, in a method for producing a plastic lens in which raw materials such as a polyisocyanate compound and a polythiol compound containing an aromatic polyisocyanate compound are mixed and reacted, The inventors have found that the impurities can be removed by filtering and purifying the polyisocyanate compound at a specific stage, thereby completing the present invention.

  That is, the present invention relates to a method for producing a plastic lens in which a raw material containing at least one polyisocyanate compound and at least one polythiol compound is mixed and reacted, and at least one aromatic polyisocyanate compound is used as the polyisocyanate compound. Is used, and the aromatic polyisocyanate compound is filtered and purified before mixing with the polythiol compound.

  According to the production method of the present invention, even when an aromatic polyisocyanate compound is used as a raw material, it is possible to produce a plastic lens excellent in transparency without turbidity or spider without passing through a complicated process.

  The method for producing a plastic lens of the present invention is a production method in which a raw material containing at least one polyisocyanate compound and at least one polythiol compound is mixed and reacted, and at least one aromatic polyisocyanate compound is used as the polyisocyanate compound. And the aromatic polyisocyanate compound is filtered and purified before mixing with the polythiol compound.

The polyisocyanate compound is rich in reactivity and easily generates urea and oligomers (including oligomer aggregates). In particular, aromatic polyisocyanate compounds have a prominent tendency, and some of them form oligomers with time.
Therefore, when the aromatic polyisocyanate compound is used as a raw material for producing a plastic lens, the present inventor is responsible for the impurities that are one of the causes of turbidity and spider in the lens. It may be called an oligomer.) Furthermore, the inventor has clarified that the oligomer is dissolved in a mixture of various raw materials including a polythiol compound and precipitated during the polymerization reaction.
From the above, in the present invention using the polyisocyanate compound and the polythiol compound as raw materials, the aromatic polyisocyanate compound is mixed with the polythiol compound in order to prevent impurities from being deposited on the lens even if the aromatic polyisocyanate compound is used as the raw material. It is important to remove the oligomers before.
The smaller the oligomer content in the mixture, the better, and it depends on the mixing ratio with the polyisocyanate compound and polythiol compound, but generally the oligomer content in the mixture is 0.5% by mass or more, the spider and turbidity Is likely to occur.

[Filter purification]
In the present invention, as a method for removing the oligomer from the aromatic polyisocyanate compound, filtration purification of the aromatic polyisocyanate compound is performed. Since the filtration purification is a simple purification method that does not require complicated operations, the oligomer can be efficiently and easily removed. Moreover, the said filtration refinement | purification can also remove the impurity which causes the cloudiness of a lens other than an oligomer, or a spider.

The temperature of the filtration purification may be higher than the freezing point temperature of the aromatic polyisocyanate compound, and may be appropriately adjusted depending on the type of the aromatic polyisocyanate compound, but if the temperature is too high, the oligomer cannot be dissolved and removed. On the other hand, if the temperature is too low, the monomer crystallizes and the yield decreases. Therefore, a preferable filtration purification temperature is within the freezing point temperature of the aromatic polyisocyanate compound plus 10 ° C., more preferably within the freezing point temperature plus 5 ° C., and even more preferably within the freezing point temperature plus 3 ° C.
In the case of using a plurality of aromatic polyisocyanate compounds, filtration purification may be carried out by mixing two or more kinds, but it is preferable to carry out each one alone. Further, the filtration purification may be performed after mixing one or more polyisocyanate compounds other than the aromatic polyisocyanate compound.

Since the oligomer is easily dissolved in the raw material monomer, particularly the polythiol compound, the filtration purification is performed before mixing with the polythiol compound, but an amount of the polythiol compound that does not dissolve the oligomer within the range that does not impair the effects of the present invention is reduced. Filtration purification may be performed after mixing with the polyisocyanate compound.
In the present invention, when raw material monomers other than polyisocyanate compounds and polythiol compounds are used in combination, filtration purification is preferably performed before mixing with raw material monomers other than polyisocyanate compounds. In order to more surely remove the impurities that cause the above, it is more preferable to perform filtration purification before mixing with raw materials other than polyisocyanate compounds, that is, raw material monomers other than polyisocyanate compounds and various additives.
In addition, since oligomers are easily formed over time, the filtration purification is preferably performed immediately before reacting with other raw materials.

As a method of filtration purification, any method such as pressure filtration, vacuum filtration, centrifugal filtration, and natural filtration may be used. The filter medium is not particularly limited as long as the raw material to be used is resistant. For example, polypropylene, polytetrafluoroethylene, glass fiber, or the like can be used.
The smaller the filtration diameter of the filter, the more effective it is for removing oligomers. Preferably, the filter diameter is 5.0 μm or less. However, if it is too small, it takes too much time for purification by filtration. Therefore, it is more preferably 0.05 μm or more and 1.0 μm or less, and further preferably 0.05 μm or more and 0.5 μm or less.
Further, the number of times of filtration purification is usually once as long as the oligomer can be removed, but may be repeated a plurality of times.

[Polyisocyanate compound]
In the present invention, at least one aromatic polyisocyanate compound is used as the polyisocyanate compound as a raw material.
Examples of the aromatic polyisocyanate compound include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, o-xylylene diisocyanate, and m-xylylene diisocyanate. Isocyanate, p-xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, ethylphenylene diisocyanate, isopropylphenylene diisocyanate, diethylphenylene diisocyanate, diisopropylphenylene diisocyanate, trimethylbenzene Triisocyanate, benzene triisocyanate and the like can be used. These aromatic polyisocyanate compounds may be used alone or in combination of two or more.
Among the above examples, it is preferable to use 4,4′-diphenylmethane diisocyanate which is industrially easily available. Since 4,4′-diphenylmethane diisocyanate easily forms an oligomer with time, the production method of the present invention can exert its effect remarkably.

In addition to the aromatic polyisocyanate compound, aliphatic and alicyclic polyisocyanate compounds can be used as the polyisocyanate compound.
Examples of the aliphatic polyisocyanate compound include 1,6-hexamethylene diisocyanate, lysine ester triisocyanate, mesitylene triisocyanate, 1,3,6-hexamethylene triisocyanate, and alicyclic polyisocyanate compound. As, for example, isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane 4,4′-diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-bis (isocyanatomethyl) cyclohexane 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3,5-tris (isocyanatomethyl) cyclohexane Sun, bicycloheptane triisocyanate and the like can be used. These aliphatic and alicyclic polyisocyanate compounds may be used alone or in combination of two or more.

[Polythiol compound]
Examples of the polythiol compound that is a raw material in the present invention include ethylene glycol bis (2-mercaptoacetate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris ( 2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), trimethylolethane tris (2-mercaptoacetate), trimethylolethanetris (3-mercaptopropionate), dichloroneopentylglycolbis (3 -Mercaptopropionate), dibromoneopentylglycol bis (3-mercaptopropionate), dipentaerythritol hexakis (2-mercaptoacetate) 2,5-bismercaptomethyl-1,4-dithiane, 4,5-bismercaptomethyl-1,3-dithiane, bis [(2-mercaptoethyl) thio] -3-mercaptopropane, bis (mercaptomethyl) -3,6,9-trithiaundecane-1,11-dithiol and the like can be used. These polythiol compounds may be used independently and may use 2 or more types.

  The blending ratio of the polyisocyanate compound and the polythiol compound may be a ratio in which the molar ratio of NCO group / SH group is usually 0.5 to 2.0, preferably 0.95 to 1.05. If the NCO group / SH group molar ratio is 0.95 or more, almost no unreacted NCO group remains, and if it is 1.05 or less, almost no unreacted SH group remains. Within this range, an ideal polymer with few unreacted groups can be obtained.

  Moreover, in this invention, raw material monomers other than the said polyisocyanate compound and polythiol compound can be used, and if it is generally used as a raw material monomer of a plastic lens, there will be no restriction | limiting in particular.

[Additive]
In the present invention, in addition to the polyisocyanate compound and the polythiol compound, additives such as a polymerization catalyst, an ultraviolet absorber and a release agent can be used as raw materials as necessary, and these additives may be used in combination.
As a polymerization catalyst, an organic tin compound is preferable, for example, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dimethyltin dichloride, monomethyltin trichloride, trimethyltin chloride, tributyltin chloride, tributyltin fluoride, Dimethyltin dibromide or the like can be used. These polymerization catalysts may be used independently and may use 2 or more types.
The mixing ratio of the polymerization catalyst is usually in the range of 0.001 to 1.00 parts by mass with respect to 100 parts by mass of the total amount of the monomer composition. Within the above range, the polymerization rate can be easily adjusted.

Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octoxybenzophenone. Various benzophenone compounds such as 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone and 2,2′-dihydroxy-4-methoxybenzophenone; 2- (2′-hydroxy-5 '-Methylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl) -5'-methylphenyl) -5-chlorobenzotriazole, 2- 2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2 ′ -Hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole and 2- (2-hydroxy-4-octyloxyphenyl) benzotriazole Various benzotriazole compounds; dibenzoylmethane, 4-tert-butyl-4′-methoxybenzoylmethane and the like can be used. These ultraviolet absorbers may be used alone or in combination of two or more.
The blending ratio of the ultraviolet absorber is usually in the range of 0.01 to 10.00 parts by mass with respect to 100 parts by mass of the total amount of the monomer composition. A more preferable range is 0.05 to 1.00, and if the blending ratio is 0.05 or more, a sufficient ultraviolet absorption effect is obtained, and if it is 1.00 or less, the resin is not markedly colored.

Examples of the release agent include isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, nonyl acid phosphate, decyl acid phosphate, isodecyl acid phosphate, tridecyl acid phosphate, stearyl acid phosphate, Phosphoric acid monoester compounds such as propyl phenyl acid phosphate and butyl phenyl acid phosphate; diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, diisodecyl acid phosphate, bis (tridecyl acid phosphate), distearyl Acid phosphate, dipropyl phenyl acid phosphate, dibutyl phenol Or the like can be used phosphoric acid diester compounds such as Le acid phosphate and butoxyethyl acid phosphate. These release agents may be used alone or in combination of two or more.
The compounding ratio of the release agent is usually in the range of 0.01 to 1.00 parts by mass with respect to 100 parts by mass of the total amount of the monomer composition. If it is in the said range, mold release acceleration | stimulation can be exhibited effectively and work does not become unreasonable.

[Mixing method and polymerization reaction]
In the present invention, there is no particular limitation on the mixing order of the raw materials such as the above-mentioned polyisocyanate compound, polythiol compound and additives used as necessary. For example, an additive may be added and mixed after mixing the polyisocyanate compound and the polythiol compound, and after mixing one of the polyisocyanate compound and the polythiol compound with the additive, the other is added and mixed. Also good.

The reaction of the mixture in which at least the polyisocyanate compound, the polythiol compound and the additive are mixed is a polymerization reaction performed by heating the mixture as necessary, and is preferably cast polymerization.
In this cast polymerization, for example, a mixture obtained by mixing a polyisocyanate compound, a polythiol compound, and an additive is injected into a mold die that is a combination of a glass or metal mold and a resin gasket, thereby performing polymerization. The polymerization temperature and polymerization time are generally about 0.5 to 72 hours at 0 to 150 ° C., although depending on the type of raw material used.
According to the manufacturing method of the present invention described above, even when an aromatic polyisocyanate compound is used as a raw material, it is possible to manufacture a plastic lens having excellent transparency without turbidity and humor without undergoing complicated processes. it can.

The present invention will be described with reference to examples, but the present invention is not limited to these examples.
In Examples and Comparative Examples, physical properties were evaluated by the following methods.
(1) Appearance The appearance immediately before polymerization of the mixture in which the raw materials were mixed was visually observed, and the obtained lens after polymerization was visually observed in a dark room under a fluorescent lamp. Transparency was evaluated.
(2) Turbidity The turbidity of the obtained lens was measured visually based on JIS standard (JIS K0101 standard for industrial water test method).

[Example 1]
As filtration purification, pressure filtration was performed on 4,4′-diphenylmethane diisocyanate [MDI] melted in a warm bath using a polytetrafluoroethylene [PTFE] membrane filter having a filtration diameter of 0.2 μm at a filtration purification temperature of 40 ° C. It was. Next, 53.95 g of filtered and purified MDI was charged into a 500 ml eggplant type flask, and 0.05 g of JP-513 (trade name, manufactured by Johoku Chemical Co., Ltd.) and 0.03 g of dimethyltin dichloride were added as a release agent. Stir. When these were completely dissolved, 2,5-dimercaptomethyl-1,4-dithiane [DMMD] 29.74 g and pentaerythritol tetrakis (2-mercaptoacetate) [PETMA] 16.31 g were blended, and 0.13 kPa ( The mixture was stirred under reduced pressure at 1.0 Torr) for 20 minutes to obtain a mixture.
This mixture was cast into a lens mold having a center thickness of 2 mm through a PTFE membrane filter having a thickness of 1.0 μm, and polymerized by a temperature program from an initial temperature of 30 ° C. to a final temperature of 120 ° C. over 24 hours to obtain a lens. . Table 1 shows the results of the above physical property evaluation of the obtained lens.

[Example 2]
As filtration purification, 44.74 g of 4,4′-diphenylmethane diisocyanate [MDI] melted in a warm bath and 7.52 g of 1,6-hexamethylene diisocyanate [HDI] were mixed, and the filtration diameter was 40 ° C. Pressure filtration was performed using a 0.2 μm polytetrafluoroethylene [PTFE] membrane filter. Next, the whole amount of filtered and purified MDI and HDI was charged into a 500 ml eggplant-shaped flask, and 0.05 g of JP-513 (trade name, manufactured by Johoku Chemical Co., Ltd.) and 0.03 g of dimethyltin dichloride were added as a release agent. And stirred. When these were completely dissolved, 30.83 g of 2,5-dimercaptomethyl-1,4-dithiane [DMMD] and 16.91 g of pentaerythritol tetrakis (2-mercaptoacetate) [PETMA] were blended at 0.13 kPa. The mixture was stirred under reduced pressure for 20 minutes to obtain a mixture.
This mixture was cast into a lens mold having a center thickness of 2 mm through a PTFE membrane filter having a thickness of 1.0 μm, and polymerized by a temperature program from an initial temperature of 30 ° C. to a final temperature of 120 ° C. over 24 hours to obtain a lens. . Table 1 shows the results of the above physical property evaluation of the obtained lens.

[Example 3]
A lens was obtained in the same manner as in Example 1 except that the PTFE membrane filter having a filtration diameter of 0.2 μm was changed to a PTFE membrane filter having a filtration diameter of 1.0 μm. Table 1 shows the results of the above physical property evaluation of the obtained lens.

[Example 4]
A lens was obtained in the same manner as in Example 2 except that the PTFE membrane filter having a filtration diameter of 0.2 μm was changed to a PTFE membrane filter having a filtration diameter of 1.0 μm. Table 1 shows the results of the above physical property evaluation of the obtained lens.

[Comparative Example 1]
After charging 53.95 g of 4,4′-diphenylmethane diisocyanate [MDI] into a 500 ml eggplant type flask and melting in a warm bath with stirring, JP-513 as a mold release agent (trade name, manufactured by Johoku Chemical Co., Ltd.) 0.05 g and 0.03 g of dimethyltin dichloride were added and stirring was continued. When these were completely dissolved, 2,5-dimercaptomethyl-1,4-dithian [DMMD] 29.74 g and pentaerythritol tetrakis (2-mercaptoacetate) [PETMA] 16.31 g were blended, and 0.13 kPa. The mixture was stirred under reduced pressure for 20 minutes to obtain a mixture.
This mixture was cast into a lens mold having a center thickness of 2 mm through a PTFE membrane filter having a thickness of 1.0 μm, and polymerized by a temperature program from an initial temperature of 30 ° C. to a final temperature of 120 ° C. over 24 hours to obtain a lens. . Table 1 shows the results of the above physical property evaluation of the obtained lens.

[Comparative Example 2]
A 500 ml eggplant-shaped flask was charged with 44.74 g of 4,4′-diphenylmethane diisocyanate [MDI] and 7.52 g of hexamethylene diisocyanate [HDI] and melted in a warm bath with stirring, and then JP-513 ( (Trade name, manufactured by Johoku Chemical Co., Ltd.) 0.05 g and 0.03 g of dimethyltin dichloride were added and stirring was continued. When these were completely dissolved, 30.83 g of 2,5-dimercaptomethyl-1,4-dithiane [DMMD] and 16.91 g of pentaerythritol tetrakis (2-mercaptoacetate) [PETMA] were blended at 0.13 kPa. The mixture was stirred under reduced pressure for 20 minutes to obtain a mixture.
This mixture was cast into a lens mold having a center thickness of 2 mm through a PTFE membrane filter having a thickness of 1.0 μm, and polymerized by a temperature program from an initial temperature of 30 ° C. to a final temperature of 120 ° C. over 24 hours to obtain a lens. . Table 1 shows the results of the above physical property evaluation of the obtained lens.

  According to the production method of the present invention, even when an aromatic polyisocyanate compound is used as a raw material, impurities are not precipitated, and a plastic lens having excellent transparency without turbidity and spiders is obtained without going through complicated steps. Since it can be manufactured, the present invention is useful in the field of various plastic lenses such as glasses and cameras.

Claims (5)

  In a method for producing a plastic lens in which a raw material containing at least one polyisocyanate compound and at least one polythiol compound is mixed and reacted, at least one aromatic polyisocyanate compound is used as the polyisocyanate compound, and the aromatic A method for producing a plastic lens, wherein the polyisocyanate compound is filtered and purified before mixing with the polythiol compound.   The method for producing a plastic lens according to claim 1, wherein the aromatic polyisocyanate compound is filtered and purified before mixing with a raw material other than the polyisocyanate compound.   The method for producing a plastic lens according to claim 1 or 2, wherein the filtration purification is performed within a freezing point temperature of the aromatic polyisocyanate compound plus 5 ° C or less using a filter having a filtration diameter of 1.0 µm or less.   The method for producing a plastic lens according to any one of claims 1 to 3, wherein the filtration purification removes an oligomer of an aromatic polyisocyanate compound and / or an aggregate of oligomers.   The method for producing a plastic lens according to any one of claims 1 to 4, wherein the aromatic polyisocyanate compound is 4,4'-diphenylmethane diisocyanate.