JPH03173613A - Manufacture of plastic lens - Google Patents

Abstract

PURPOSE:To manufacture a plastic lens simply and with good productivity by forming a thermoplastic polyamide film layer on a part or the whole of the surface of a gasket. CONSTITUTION:A thermoplastic polyamide film layer is formed on a part or the whole of the surface of a gasket to be used. At that time, it is sufficient to form the film layer on a contact surface with a monomer component out of the gasket surface, or the same can be formed on the whole of the surface. In the case that the bonding properties of said thermoplastic polyamide and the gasket is not sufficient, a thermoplastic polyamide film layer can be formed on the gasket through a proper intermediate bonded layer. Also, in the case that thermoplastic polyamide can be dissolved in an organic solvent, as far as the solvent is not affected by the polymierized monomer component, a plasticizer can be added to a polyamide coating agent preliminarily after thermoplastic polyamide is dissolved in the organic solvent. Also the film thickness of polyamide film layer can be properly selected according to the composition of the monomer component to be used or the desired shape of a plastic lens, and it is suitable to form 1-500mum film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a manufacturing method for molding a plastic lens by cast polymerization using a gasket.

[Conventional technology]

Diethylene glycol bisallyl carbonate (hereinafter abbreviated as CR-39) is widely used as a monomer for producing plastic lenses by the cast polymerization method.Plastic lenses are extremely superior to conventional inorganic glasses. CR-39 has characteristics such as being impact resistant, lightweight, and easy to dye.However, CR-39 is
Because the refractive index is 1.50, which is lower than inorganic glass lenses,
The disadvantage is that the edge of the lens becomes thicker.

Therefore, it is desired to develop a high refractive index plastic lens that can be made thinner and more fashionable.

In order to obtain such a plastic lens with a high refractive index, monomers made of aromatic compounds have been introduced as polymerizable monomers. (For example, JP-A-57-104
101, JP-A-6O-258501) In addition, the above-mentioned plastic lens having a high refractive index is molded by injecting a polymerizable monomer into a mold consisting of a spacer and a mold, sealing it, and then curing it by heating. will be carried out.

Conventionally, the above-mentioned vacuum material called a gasket has been made of synthetic resins such as flexible polyvinyl chloride (hereinafter abbreviated as PVC), ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA), and ethylene-ethyl acrylate (hereinafter abbreviated as EEA). is common.

Gaskets made of EVΔ are suitable for aliphatic monomers, such as CR-39. However, for aromatic monomers such as vinyl aromatic monomers such as styrene and chlorostyrene, the plasticizer and low molecular weight components contained in the gasket are leached out during polymerization and heating, resulting in a cloudy plastic lens. Or Gasquera! Due to the swelling, some of the monomer leaks out, causing defects in the shape of the plastic lens and other problems with the gasket's resistance to polymerizable monomers.

As a method for improving the resistance to monomers such as Gaskera), Japanese Patent Application Laid-Open No. 60-112407 describes a method of coating the gasket surface with a fluororesin.
No. 14816 proposes a method of coating the gasket surface with a water-soluble polymer.

[Problems to be Solved by the Invention] In the method of coating the surface of a gasket with a fluororesin, the fluororesin must be cured and dried at high temperatures. Therefore, the gas kera 1 base material is limited to a material with high heat resistance. Further, there are problems such as the fluororesin itself being expensive.

On the other hand, the method of coating with a water-soluble polymer has problems such as insufficient adhesion between the gasket base material and the water-soluble polymer layer.

The present invention solves the above-mentioned drawbacks of the conventional method by using a gasket coated with a coating material that is inexpensive and has excellent resistance to monomers, and makes it possible to manufacture plastic lenses easily and with improved productivity. (The purpose is to provide a method for manufacturing.

[Means and effects for solving the problem] The present inventors
In light of this current situation, we have conducted extensive studies and found that by forming a heat-growth-resistant polyamide film on the surface of a gasket for plastic lens molding, the gasket will not be attacked by polymerizable monomer components. They discovered this and completed the present invention.

In other words, the present invention provides a method for manufacturing a plastic lens by casting polymerizing a polymerizable monomer component in a mold equipped with a gasket, in which a coating layer of thermoplastic polyamide is formed on a part or the entire surface of the gasket. The present invention relates to a method of manufacturing a plastic lens characterized in that the plastic lens is formed with a thickness of 1+.

As the gasket in the present invention, various conventionally known materials can be used, and although there are no particular restrictions, it is common to use a synthetic resin gasket. Specific examples include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, soft polyvinyl chloride, polyolefin elastomer, polyester elastomer, polyamide elastomer, and the like.

The gasket used in the present invention has a thermoplastic polyamide coating layer formed on a part or the entire surface of the gasket. At this time, it is sufficient to form the coating layer on the surface of the gasket that is in contact with the monomer component, but it may be formed on the entire surface. The thermoplastic polyamide mentioned here is not particularly limited as long as it has good adhesion to the gasket (and can be easily coated), but specifically, examples include nylon-6, nylon-66, nylon-610, etc. , homopolymers such as nylon-612, nylon-11, and nylon-12, various copolymerized nylons, and alcohol-soluble polyamides.

If the adhesion between the thermoplastic polyamide and the gasket is insufficient, a thermoplastic polyamide coating layer can be applied to the gasket via a suitable intermediate adhesive layer. Further, when the thermoplastic polyamide is soluble in an organic solvent, a plasticizer can be added in advance to the polyamide coating after being dissolved in the organic solvent, as long as the plasticizer is not attacked by the polymerizable monomer component. Alternatively, the gasket surface may be roughened in advance and a polyamide coating layer may be provided thereon.

The thickness of the polyamide coating layer is appropriately selected depending on the composition of the monomer components used and the desired shape of the plastic lens, but it is preferably 1 to 500 microns thick.

When the thickness is less than 1μ, sufficient resistance to monomers may not be obtained. Moreover, if the thickness is more than 500 μm, the sealing performance with the glass mold may deteriorate.

To coat the gasket with thermoplastic polyamide, if the polyamide is insoluble in organic solvents, a method such as spraying or dip method is used after melting the polyamide at a temperature higher than the heat distortion temperature. In such cases, after dissolving it in an appropriate solvent, spraying, dipping, brushing, etc. are used.

Among them, the dip method is effective as a simple and inexpensive coating method.

For organic solvent-soluble polyamide, the applied gasket base material can be dried naturally by leaving it at room temperature.
It is also possible to speed up drying by forcibly heating.

Furthermore, in order to strengthen the coated film after coating and drying, the strength of the film is increased through a curing treatment such as electron beam irradiation, ultraviolet irradiation, gamma ray irradiation, etc., or chemical post-treatment with formalin, etc. It is also possible to further improve the resistance to polymerizable monomer components.

The present invention is achieved by cast-polymerizing a polymerizable monomer component in a mold equipped with a gasket on which a coating layer of the thermoplastic polyamide obtained as described above is formed. Although the polymerizable monomer component should be selected depending on the purpose, the effects of the present invention are significantly exhibited when the polymerizable monomer component contains an aromatic compound. The aromatic monomers mentioned here are, for example, styrene and styrene derivatives CH, =CH represented by the following general formula (1) (where R is hydrogen or a methyl group, Ro is hydrogen, or a halogen group excluding fluorine). , methyl group or ethyl group, n is O
It is an integer of ~5. ), aromatic (meth)acrylates such as phenyl (meth)acrylate, chlorphenyl (meth)acrylate, benzyl (meth)acrylate, and chlorobenzyl (meth)acrylate; diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, tetrabromo diallyl Examples include monomers having an aromatic ring such as orthophthalate, tetrabromo diallyl isophthalate, and tetrabromo diallyl terephthalate.

Moreover, it is also possible to use these monomers having an aromatic ring in combination with monomers having no copolymerizable aromatic ring.

In the present invention, a liquid containing a polymerizable monomer component is poured into a mold made of glass or metal and a gasket coated with thermoplastic polyamide, and the monomer component is cast-polymerized. Known additives such as ultraviolet absorbers and light stabilizers can be added to this polymerizable monomer component, if necessary. Cast polymerization is carried out by methods such as heating polymerization, ultraviolet light polymerization, and electron beam polymerization, but thermal polymerization is convenient. In thermal polymerization, a known radical polymerization initiator can be used.

[Effects of the present invention]

According to the present invention, by using a gasket on which a thermoplastic polyamide coating layer is formed, the polymerization yield can be improved in a simple manner, and moreover, a large amount of aromatic compounds can be added to the polymerizable monomer component. This made it possible to increase the refractive index of plastic lenses. Therefore, the method for manufacturing a plastic lens of the present invention is suitable for manufacturing spectacle lenses, particularly corrective lenses.

[Examples of the Invention] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Reference Example 1 Ultraamide IC which is alcohol-soluble polyamide
(BASF brand name) 30g, methanol 270g and water 3
It was added to 0 g of the mixed solution and dissolved at 60° C. with stirring to obtain a coating solution. This coating solution was applied by a dip method to a polyolefin elastomer gasket base material that had been cleaned with Freon 113, and was left to dry at room temperature for 12 hours to obtain a gasket coated with polyamide. Gasquera! - and coating materials are shown in Table-1.

Reference Examples 2 to 8 Covered gaskets were obtained by repeating the same operations as in Reference Example 1, except that the gasket base material and polyamide shown in Table 1 were used.

Example 1 Using the gasket obtained in Reference Example 1, a polymerizable monomer component consisting of 50 parts by weight of styrene and 50 parts by weight of 2,2-bis(3,5-dibromo-4-methacryloyloxyethoxyphenyl)propane was prepared. , lauroyl peroxide 0
．． Add 4 parts by weight and 0°4 parts by weight of 2-(2-hydroxy-5°-methylphenyl)benzotriazole, and heat to 50°C.
After heating and polymerizing linearly from 50"C to 110°C for 15 hours and at 110°C for 1 hour, the gasket and glass mold were separated. The resulting lens retained a good shape, It was transparent and had no cloudiness.The results are shown in Table 2.

Example 2 Using the gasket obtained in Reference Example 8, 12 parts by weight of xylylene diisocyanate, 2-(4-acryloxyethoxy-3,5-dibromophenyl-2-(4-hydroxyethoxy-3,5-dibromo) 11,000 pp of dibutyltin dilaurate was added to a polymerizable monomer component consisting of 38 parts by weight of phenyl)propane and 50 parts by weight of chlorostyrene, and the mixture was heated at 50°C for 2 hours.Then, it was cooled to room temperature and di-t-butylper 0.1 part by weight of oxide was added. After polymerization was carried out linearly from 60°C to 110°C for 30 hours, the lens was separated from the gasket and glass mold. The resulting lens retained a good shape. It was transparent and had no cloudiness.The results are shown in Table 2.

Examples 3 to 10 1 2 Lenses were obtained by repeating the same operations as in Example 1, except that the gasket base material and polymerizable monomer components shown in Table 2 were used. The resulting lens retained good shape, was transparent, and had no weight. The results are also shown in Table-2.

Comparative Examples 1 to 10 Lenses were obtained in the same manner as in Examples 1 to 10, except that the gasket base material was used as it was without being coated. These results are shown in Table-3.

In addition, the evaluation in Examples was performed by the following method.

・White cloudiness of the lens The obtained lens was irradiated with a xenon lamp, and the presence or absence of cloudiness was observed.

- If there was no liquid leakage during shape polymerization, it was marked as ○, and if the lens was chipped due to liquid leakage due to poor sealing performance, it was marked as ×.

- If the glass mold and lens did not come apart during polymerization (the mold and lens peeled off), it was rated as ○, and if there was separation from the mold during polymerization, it was rated as ×.

Abbreviations in the table St: Styrene C1-3t: Chlorstyrene α-3t: α-methylstyrene Br, BMEPP: 2,2-bis(3,5-dibromo-4-methacryloyloxyethoxyphenyl)propane AEBr2HEBr2PP: 2-(4-acryloxyethoxy-3゜5-dibromophenyl)-2-(
4-hydroxyethoxy-3,5-dibromophenyl)
Propane EGDMA: Ethylene glycol dimethacrylate 4EG: Tetraethylene glycol dimethacrylate 14EG: Tetradeforce ethylene glycol dimethacrylate 1 route TMPTM ・Trimethylolpropane trimethacrylate HD: l,6-hexanethiol dimethacrylate PETM ・Pentaerythritol trimethacrylate 9PG: Nona Propylene glycol dimethacrylate MMA: Methyl methacrylate SEG: 2-methacryloylthioethyl methacrylate 32EG: Bis(2-methacryloylthioethyl) sulfide 53EG: 1,2-bis(2-methacryloylthioethylthio)ethane 8N: Acrylonitrile ADC Nidiethylene glycol Bisallyl carbonate XDI: Xylylene diisocyanate Table-1 Erbamide 8063; Du Pont product name Table-2

Claims (2)

[Claims] (1) In a method of manufacturing a plastic lens by casting polymerizing a polymerizable monomer component in a mold equipped with a gasket, a thermoplastic polyamide coating layer is formed on a part or the entire surface of the gasket. A method for manufacturing a plastic lens, characterized by: (2) The method for producing a plastic lens according to claim 1, wherein the polymerizable monomer component essentially contains an aromatic monomer.