JPH095680A - Method for manufacturing plastic lens - Google Patents

Abstract

(57) [Abstract] [Purpose] After removing the mold by forming a hard coat film on the inner surface of the mold in the method of manufacturing a plastic lens,
An object of the present invention is to provide a technique having a good surface hardness, which enables high productivity, high quality, and high yield. A method for producing a plastic lens, characterized by forming a coating film on the inner surface of a glass mold in advance and fixing the outer periphery of the mold with an adhesive tape in the method of casting polymerization using a glass mold. [Effect] To provide a technique for manufacturing a plastic lens having a low surface hardness and a plastic lens having a poor peeling property from a glass mold with high productivity, high quality and high yield.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic lens having high surface hardness, good productivity, high productivity, high quality and high yield.

[0002]

2. Description of the Related Art As a method for producing a plastic lens, a casting method in which a monomer is poured into a glass mold and hardened by heat or light, a cutting and polishing method in which a monomer is cut out from a plastic plate and polished and finished, and a thermoplastic resin is used. There are an injection molding method, a hot press method, and the like.

As a lens material, polymethylmethacrylate as a sunglasses lens, diethylene glycol bisallyl carbonate for correcting vision, a copolymer of styrene and a bromine-containing methacrylate, and an isocyanate group-containing material. A polymer of a monomer and a monomer containing a hydroxy group or a thiol group is used.

However, the casting method has become the mainstream for the production of high-performance plastic lenses.

Here, the cast molding method is to inject a liquid curable compound into a mold having a shape of a lens, heat it,
This is a method of obtaining a lens product by removing the mold after curing by a method such as ultraviolet rays.

Since the surface height of these lenses is low, a hard coat, an inorganic vapor deposition, or a hard coat and an inorganic vapor deposition film is applied to the lens surface after demolding to raise the surface height to cope with it. Therefore, the lens is scratched before the surface treatment, the lens needs to be cleaned, and there are problems in yield and running cost.

To solve this problem, Japanese Patent Publication No. 5-356
52, Japanese Examined Patent Publication No. 6-20756, a hard coat is applied to a mold in advance and cured, and then a monomer solution is injected into a space formed by the two molds and an annular gasket to polymerize the monomer and then the mold and the gasket. I took out the mold more and got a lens with a hard coat.

However, in the manufacture of a lens of a mold and an annular gasket, a chamfered portion that contacts the gasket is required on the outer peripheral portion of the use surface of the mold. When the hard coat is applied to this part, the part is in contact with the gasket and does not contact with the monomer liquid, so that the hard coat remains in a ring shape on the outer periphery of the mold after polymerization and demolding. Therefore, when reusing the demolded mold, it is necessary to drop the hard coat on the outer peripheral portion of the use surface, and since it is the use surface, a large load is applied to the cleaning process, which adversely affects yield and cost. Further, when the mold is continuously used without dropping the hard coat, the hard coat liquid is not leveled well due to the difference in surface tension between the mold surface and the hard coat surface remaining on the outer periphery of the mold, which causes a problem in appearance. . In addition, there are various problems such that the packing property of the surface in contact with the mold and the gasket is deteriorated and the liquid curable compound leaks.

[0009]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to apply a hard coat to a mold and cure the mold to produce a plastic lens by a casting polymerization method. It is to obtain a plastic lens having good surface quality, high yield, and high surface height.

[0010]

The present inventor has found that the above-mentioned problems can be solved all at once by fixing the space formation of two molds with an adhesive tape.

That is, according to the present invention, two molds are cleaned, a hard coat liquid is applied and cured on the surface to be used, two molds are positioned at a predetermined interval, and an adhesive seal is formed around the side surface. A plastic lens characterized in that a liquid curable compound is injected into a mold formed by surrounding the two molds and surrounded by the two molds and the adhesive sheet and polymerized. It is a manufacturing method.

The method of fixing a mold with an adhesive tape according to the present invention does not require a chamfered portion in contact with the gasket on the outer peripheral portion of the use surface of the mold, as compared with the method of fixing a mold and an annular gasket. Therefore, the following problems do not occur. That is, when the hard coat is applied to the chamfered portion, the hard coat remains in a ring shape on the outer peripheral portion of the mold after polymerization and demolding since the hard coat is in contact with the gasket and is not in contact with the monomer liquid. Therefore, when reusing the demolded mold, it is necessary to drop the hard coat on the outer peripheral portion of the use surface, and since it is the use surface, a large load is applied to the cleaning process, which adversely affects yield and cost. Further, when the mold is continuously used without dropping the hard coat, the hard coat liquid is not leveled well due to the difference in surface tension between the mold surface and the hard coat surface remaining on the outer periphery of the mold, which causes a problem in appearance. . Further, the packing property of the surface in contact with the mold and the gasket is deteriorated, and the liquid curable compound leaks.

The liquid curable compound for plastic lenses used in the present invention is not particularly limited. Further, the polymerization method can be applied to any polymerization method such as thermal polymerization and photopolymerization.

There is no particular limitation on the hard coat liquid, but the hard coat liquid is preferably applied by spin coating or spray coating. In the depping method, the hard coat liquid adheres to the non-use surface and the outer peripheral side surface of the glass mold, which causes a heavy load on cleaning. In addition, the packing property deteriorates, and the liquid curable compound leaks.

The tape adhesive constituting the present invention may be selected from acrylic resin type, silicone type, natural rubber type and the like in accordance with the characteristics of the liquid curable compound for plastic lenses. The pressure-sensitive adhesive may have any thickness, but it is preferably about 2 to 50 μm in consideration of drawing out from the tape and workability into a glass mold.

The sheet as the base material of the tape may be appropriately selected from plastic film, metal foil, paper, cloth and the like, but from the viewpoint of chemical resistance, heat resistance, strength, cost, etc., the polyimide film. , Polyethylene terephthalate film,
A polypropylene film is preferable, and a polyethylene terephthalate film is particularly preferable. The film may have any thickness, but it is preferably about 5 to 50 μm in view of processability into a glass mold.

Further, the base film may be subjected to a corona discharge treatment or an undercoating treatment to improve the non-adhesiveness with the adhesive. In addition, a modifier such as a heat resistance improver or a modifier for improving adhesion may be appropriately added to the pressure-sensitive adhesive as long as it does not cause turbidity by being eluted in the lens monomer or hindering polymerization or curing reaction. Good.

As a method for producing an adhesive sheet, for example, when a film is used as a substrate, a catalyst is added to an adhesive solution in which the adhesive is dissolved in an organic solvent such as toluene or xylene, and this is used as a film. It can be obtained by applying it to and then reacting it at a predetermined temperature. Alternatively, an adhesive may be applied to the edge of the glass mold to bring the film into close contact.

Forming an antireflection film on the surface of the plastic lens obtained by the present invention is a useful means for improving the added value of the product.

As a film forming method for forming an antireflection film made of an inorganic material on the lens surface obtained in the present invention, a vacuum vapor deposition method, an ion plating method, a spattering method and the like can be mentioned. In the vacuum evaporation method, an ion beam assist method in which an ion beam is simultaneously irradiated during the evaporation may be used. As the film configuration, either a single-layer antireflection film or a multilayer antireflection film may be used.

Specific examples of the inorganic material used include Si
O ₂ , SiO, ZrO ₂ , TiO ₂ , TiO, Ti ₂ O ₃ ,
Ti ₂ O ₅ , Al ₂ O ₃ , Ta ₂ O ₅ , CeO ₂ , MgO, Y ₂
O ₃ , SnO ₂ , MgF ₂ , WO _{3 and the} like can be mentioned. These inorganic substances may be used alone or in a mixture of two or more.

Further, when forming the antireflection film, it is desirable to perform surface treatment of the hard coat film. Specific examples of the surface treatment include an acid treatment, an alkali treatment, an ultraviolet irradiation treatment, a plasma treatment by a high-frequency discharge in an argon or oxygen atmosphere, and an ion beam irradiation treatment with argon, oxygen or nitrogen.

[0023]

EXAMPLES The present invention will be described in detail, but the present invention is not limited to these examples.

The evaluation of polymerization and hard coat was carried out by the following methods.

(1) Packing property When a polymerizable monomer is cast-polymerized in a glass mold,
The case where the monomer did not leak was evaluated as ◯, and the case where the monomer leaked was evaluated as x.

(2) Appearance The appearance of the plastic lens molded product having a coating film was visually evaluated.

Example 1 A liquid composition obtained by adding 2 g of benzoin isopropyl ether as a photosensitizer to a monomer composition consisting of 40 g of pentaerythritol tetraacrylate, 30 g of trimethylolpropane triacrylate and 30 g of ethylene glycol diacrylate on the surface of a glass mold. 3 μm thick by spin coating at room temperature
Was applied to. After the coating, a 200 w high pressure mercury lamp was used for irradiation for 30 seconds from a distance of 25 cm in a nitrogen stream to obtain a cured coating film.

The outer periphery of the glass mold on which the coating film was formed in this manner was fixed with an adhesive tape (base PET 50 μm, silicone adhesive 15 μm).
-Bis [(2-mercaptoethyl) thio] -3-mercaptopropane 87 g, m-xylylene diisocyanate 94 g, di-n-butyltin dichloride 0.002 g,
2- (2-hydroxy-5-ethyl) benzotriazo-
A liquid curable composition of 0.2 g was injected, the temperature was raised from 30 ° C. to 120 ° C. over 12 hours, and the temperature was kept constant at 120 ° C. for 2 hours to complete the polymerization. After gradually cooling to room temperature, the polymerized molded product was evaluated according to the above evaluation method. The results are shown in Table 1.

Comparative Example 1 A liquid composition in which 2 g of benzoin isopropyl ether as a photosensitizer was added to a monomer composition composed of 40 g of pentaerythritol tetraacrylate, 30 g of trimethylolpropane triacrylate and 30 g of ethylene glycol diacrylate on the surface of a glass mold. The product was applied at room temperature by a spin coating method to a thickness of 3 μm. After the coating, a 200 w high pressure mercury lamp was used for irradiation for 30 seconds from a distance of 25 cm in a nitrogen stream to obtain a cured coating film.

1,2-Bis [(2-mercaptoethyl) thio] -3-in a mold composed of a glass mold and a silicone gasket on which a coating film was formed in this manner.
87 g mercaptopropane, 94 g m-xylylene diisocyanate, 0.000 di-n-butyltin dichloride
A liquid curable composition consisting of 2 g and 0.2 g of 2- (2-hydroxy-5-ethyl) benzotriazole was injected and 3
The temperature was raised from 0 ° C. to 120 ° C. over 12 hours and kept constant at 120 ° C. for 2 hours to complete the polymerization. After gradually cooling to room temperature, the polymerized molded product was evaluated according to the above evaluation method. The results are shown in Table 1.

Comparative Example 2 A liquid composition in which 2 g of benzoin isopropyl ether as a photosensitizer was added to a monomer composition consisting of 40 g of pentaerythritol tetraacrylate, 30 g of trimethylolpropane triacrylate and 30 g of ethylene glycol diacrylate on the surface of a glass mold. The product was applied at room temperature by a depping method to a thickness of 3 μm. After the coating, a 200 w high pressure mercury lamp was used for irradiation for 30 seconds from a distance of 25 cm in a nitrogen stream to obtain a cured coating film.

1,2-Bis [(2-mercaptoethyl) thio] -3-in a mold composed of a glass mold and a silicone gasket on which a film is formed in this manner.
87 g mercaptopropane, 94 g m-xylylene diisocyanate, 0.000 di-n-butyltin dichloride
A liquid curable composition consisting of 2 g and 0.2 g of 2- (2-hydroxy-5-ethyl) benzotriazole was injected and 3
The temperature was raised from 0 ° C. to 120 ° C. over 12 hours and kept constant at 120 ° C. for 2 hours to complete the polymerization. After gradually cooling to room temperature, the polymerized molded product was evaluated according to the above evaluation method. The results are shown in Table 1.

(Example 2) 30 g of dipentaerythritol pentaacrylate, 40 g of 1,4-butylene glycol diacrylate, 17 g of tri (acryloxyethyl) isocyanurate and 2- (2-hydroxy-5-tert-butylphenyl) benzo on the surface of a glass mold. A liquid composition consisting of 10 g of triazole and 3 g of methylphenylglyoxylate was spin-coated at room temperature to a thickness of 3
μm. After the coating, a 200 w high pressure mercury lamp was used for irradiation for 30 seconds from a distance of 25 cm in a nitrogen stream to obtain a cured coating film.

The outer periphery of the glass mold thus formed with a film was fixed with an adhesive tape (base PET 50 μm, acrylic adhesive 20 μm), and isophorone diisocyanate and 2-hydroxylpropyl methacrylate were reacted in the mold. 140 g of urethane dimethacrylate obtained by the above procedure and nonabutylene glycol dimethacrylate 2
0 g, 1,6-hexanediol dimethacrylate 5
g, isobornyl methacrylate 20 g, 2,4,6-trimethylbenzoyldiphenylphosphine oxide 0.03 g, t-butylperoxyisobutyrate 0.1 g, 2-hydroxy-4-methoxybenzophenone 0.05 g, tridecyl phosphate After mixing 0.2 g and stirring well at room temperature, the pressure was reduced to 50 mmHg, and the deaerated raw material was injected for 10 minutes.

Then, after irradiating 30 J / cm ² of ultraviolet rays from both sides of the mold with a metal halide lamp of 3 kW, the mold was slowly cooled to room temperature and released, and the released mold was ultrasonically washed in isopropyl alcohol. After that, hard coating was applied and cured again, assembly with an adhesive tape, monomer injection and curing were performed, and after gradually cooled to room temperature, the polymerized molded product was evaluated according to the above evaluation method. The results are shown in Table 1. (Comparative Example 3) 30 g of dipentaerythritol pentaacrylate, 40 g of 1,4-butylene glycol diacrylate, 17 g of tri (acryloxyethyl) isocyanurate, and 2- (2-hydroxy-5-t) on the surface of a glass mold.
A liquid composition consisting of 10 g of ert-butylphenyl) benzotriazole and 3 g of methylphenylglyoxylate was applied at room temperature by a spin coating method to a thickness of 3 μm. After coating, using a 200w high-pressure mercury lamp in a nitrogen stream, 2
Irradiation from a distance of 5 cm for 30 seconds gave a cured coating film.

140 g of urethane dimethacrylate obtained by reacting isophorone diisocyanate and 2-hydroxylpropyl methacrylate in a mold consisting of a glass mold and a polyethylene gasket on which a coating film has been formed in this way, nonabutylene glycol 20 g of dimethacrylate, 5 g of 1,6-hexanediol dimethacrylate, 20 g of isobornyl methacrylate,
0.03 g of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 0.1 g of t-butylperoxyisobutyrate, 0.05 g of 2-hydroxy-4-methoxybenzophenone and 0.2 g of tridecyl phosphate were mixed at room temperature. After stirring well with 50mmH
The raw material depressurized to 10 g and degassed for 10 minutes was injected.

Then, after irradiating 30 mj / cm ² of ultraviolet rays from both sides of the mold with a metal halide lamp of 3 kW, the mold was slowly cooled to room temperature and released, and the released mold was ultrasonically cleaned in isopropyl alcohol. After that, the hard coat was applied and cured again, the assembly by the gasket and the monomer injection and curing were performed, and after gradually cooled to room temperature, the polymerized molded product was evaluated according to the above evaluation method. The results are shown in Table 1.

[0038]

[Table 1]

[0039]

According to the present invention, (1) a hard coat film can be provided on the surface of a plastic lens having a low surface hardness without handling.

(2) A monomer having poor releasability between the glass mold and the plastic lens can be used.

(3) High productivity and high yield can be obtained.

[0042]

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Claims (2)

[Claims] Claims: 1. Two molds are cleaned, a hard coat liquid is applied and hardened on a surface to be used, two molds are positioned at predetermined intervals, and an adhesive sheet-like material is provided around the side surface. A method for producing a plastic lens, which comprises closely contacting each other and injecting a liquid curable compound into a mold formed by being surrounded by the two molds and the adhesive sheet to polymerize the compound. 2. A method of manufacturing a plastic lens, wherein the method of applying the hard coat liquid according to claim 1 is a spin coat method or a spray coat method.