JPH1199527A - Manufacture of plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of lenses by a method wherein a bubble-free lens is manufactured even under the condition that a liquid curable composition, the reaction of which is slow and the curing time of which is long, is employed by preventing the composition from leaking. SOLUTION: The manufacturing method of this plastic lens is so constituted as to have a first process, in which two forming molds are fixed together with a pressure sensitive adhesive tape, a second process, in which a liquid curable composition is poured in a gap formed by the two forming molds and the pressure sensitive adhesive tape, and a third process in which the liquid curable composition is cured for forming the lens, in the order named. In this case the first process is executed by employing a pressure sensitive adhesive tape having a thickness of an pressure-sensitive adhesive of 20-30 μm and a thickness of the base material 10-60 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a plastic lens. More specifically, the present invention relates to a production method capable of preventing a liquid curable composition from leaking during cast polymerization and obtaining a plastic lens without bubbles.

[0002]

2. Description of the Related Art In general, a casting method is used for manufacturing a plastic lens. With the casting molding method, the liquid curable composition is injected into the void created by the molding die having the curvature of the lens to be obtained, and after polymerization or curing by heating or light irradiation, the molding die is removed. This is how to get a lens product.

In this casting method, a gap is created by fixing and sealing the side surfaces of two molds with a gasket, but it is necessary to have a different kind of gasket according to the type of lens. There was an inconvenience that the cost was high because it was disposable.

For this reason, a method has been proposed in which the side surfaces of two molds are fixed and sealed with an adhesive tape instead of a gasket (Japanese Patent Laid-Open No. 1-294016, Japanese Patent Publication No. 3-8 / 1994).
246, Japanese Patent Publication No. 5-64564, and JP-A-6-3
No. 46034 publication).

[0005]

However, when a pressure-sensitive adhesive tape having a pressure-sensitive adhesive thickness of 40 μm and a tape base material thickness of 38 μm as in the prior art is used (Japanese Patent Laid-Open No. Hei 6-346).
034) When the liquid curable composition contains a monomer such as an allyl group, a vinyl group, or a secondary or tertiary polyisocyanate, the reaction speed is slow and it takes a long time to cure. Leakage may occur from the overlap and bubbles may form in the lens, which may significantly reduce the yield.

Accordingly, an object of the present invention is to provide a technique for adjusting the adhesive thickness and the base material thickness of an adhesive tape, preventing leakage of a liquid curable composition, and producing a lens without bubbles. I do.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a plastic lens, comprising: a first step of fixing two molds using an adhesive tape; A plastic lens having, in this order, a second step of injecting the liquid curable composition into the void formed by the step and a third step of curing and molding the liquid curable composition. In the method, the adhesive has a glue thickness of 20.
The first step is carried out by using an adhesive tape having a base material thickness of 10 to 60 μm.

[0008] The optimum paste thickness of the tape for fixing and sealing the two molds to form a void is 20 to 35 µm, and the base material thickness is 10 to 60 µm. If the paste thickness is less than 20 μm, the adhesion between the mold and the tape will be low. If it exceeds 35 μm,
A gap is likely to occur at the overlap of the loops. If the thickness of the base material is less than 10 μm, it is difficult to maintain the shape of the void. 60μ
If it exceeds m, a gap is likely to be formed at the overlap of the tape irrespective of the adhesive thickness. As a result, during the curing, leakage occurs from the overlapping portion of the tape, and bubbles are generated in the lens, which is not preferable.

According to a second aspect of the present invention, there is provided a method of manufacturing a plastic lens according to the first aspect, wherein the adhesive is a silicone-based adhesive.

As the pressure-sensitive adhesive, a silicone-based adhesive having excellent heat resistance and solvent resistance is preferable to an acrylic-based or rubber-based adhesive. Specifically, as the main polymer of the silicone-based paste, methyl vinyl silicone rubber, phenyl silicone rubber,
Silicone rubber such as fluorosilicone rubber and polyurethane silicone rubber is used. It is preferable that these base polymers have a high molecular weight and a highly cross-linked structure in order to avoid elution into the liquid curable composition. In addition, in addition to this, tackifiers, antioxidants, coloring agents,
Various additives such as a filler may be blended as required.

In a third aspect of the present invention, there is provided a plastic lens manufacturing method according to the first or second aspect, wherein the plastic film serving as a base material of the tape is made of polyethylene terephthalate or polyethylene.
Polyesters such as 2,6 naphthalate, polyolefins such as polypropylene and poly-4-methylpentene, polyimides, polyamides and polycarbonates are effective, but heat resistance and solvent resistance are effective. A biaxially stretched polyethylene terephthalate film is most suitable in terms of properties, strength, cost and the like.

According to a fourth aspect of the present invention, there is provided a method for producing a plastic lens according to any one of the first to third aspects, wherein the liquid curable composition comprises an allyl group, a vinyl group, or an isocyanate group. Characterized by containing a monomer having the formula:

The cast polymerization molding method of the present invention relates to a liquid curable composition having a slow reaction, specifically a composition containing a monomer having an allyl group, a vinyl group or an isocyanate group (containing an isocyanate group). In the case of a monomer having a polyisocyanate compound, a composition containing a secondary or tertiary polyisocyanate compound is particularly effective. As an example of the monomer having the above functional group, as the allyl monomer, ethylene glycol bisallyl carbonate, diethylene glycol bisallyl carbonate, triethylene glycol bisallyl carbonate, tetraethylene glycol -Rubisallyl carbonate, pentaethylene glycol-bisallyl carbonate
Bonnet, polypropylene glycol bisallyl carbonate, trimethylene glycol bisallyl carbonate
3-hydroxypropoxypropanol bisallyl carbonate, glycerol bisallyl carbonate,
Triglycerol bisallyl carbonate, bisphenol A diallyl ether, bisphenol S diallyl ether, ethylene glycol diallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, 1,1,1 Trimethylolpropane triallyl ether, neopentyl glycol diallyl ether, diallyl phthalate, triallyl isocyanurate and the like. Examples of the vinyl monomer include styrene, nuclear halogen-substituted styrene, vinylnaphthalene, nuclear halogen-substituted vinylnaphthalene, divinylbenzene, nuclear halogen-substituted divinylbenzene, vinyl acetate, N-vinylpyrrolidone, and derivatives thereof. As the polyisocyanate monomer, 2,4-tolylene diisocyanate
2,6-tolylene diisocyanate, diphenylmethylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate Isocyanate, transcyclohexane 1,4-diisocyanate, dicyclohexylmethylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) phosphate, m -Tetramethylxylylenediisocyanate, p-tetramethylxylylenediisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene Triisocyanate, bicycloheptane triisocyanate and the like.
These polyisocyanates are blended with polyols or polythiols to form urethane resins.

[0014] A radical polymerization initiator is added to the liquid curable composition containing an allyl monomer and a vinyl monomer used in the present invention. Specifically, the tertiary
Butyl peroxy neodecanoate, tert-butyl peroxyisobutyrate, tert-butyl peroxy
Oxypivalate, tert-butylperoxy-2
-Ethylhexanoate, diisopropyl peroxydica carbonate, dinormal propyl peroxydica carbonate, 2,2'-azobis (4-methoxy-2,4-
Dimethylvaleronitrile), 2,2'-azobis (2,
4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile and the like. The above radical polymerization initiator is generally used by adding 0.001 to 10 parts by weight to 100 parts by weight of the liquid curable composition. Also,
In the urethanization of the polyisocyanate used in the present invention, a tertiary amine compound or an organometallic compound is added as a catalyst. Specifically, N, N-dimethylcyclohexylamine, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N ", N" -pentamethyldiethylenetriamine, N, -methyl, N '-(2
Dimethylamino) -ethylpiperazine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ether, dimethyltin dichloride, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin thiocarboxy Rate, dibutyltin dimaleate, dioctyltin thiocarboxylate
G, phenylmercuric propionate, lead octenoate and the like. The urethanization catalyst is generally used by adding 0.001 to 2.0 parts by weight to 100 parts by weight of the liquid curable composition. In addition, various additives such as a polymerization inhibitor, an ultraviolet absorber, an antioxidant, a release agent, an antistatic agent, and a color adjusting dye may be added as necessary.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

(Example 1) An adhesive tape composed of a polyethylene terephthalate base material (thickness: 50 μm) and a glue containing methyl vinyl silicone rubber as a main polymer (glue thickness: 25 μm) was used. A diethylene glycol bisallyl carbonate is provided in a gap formed by fixing two glass molds.
A mixture obtained by adding 3.0 parts by weight of diisopropyl peroxydica-bonate to 100 parts by weight of the mixture was injected. Next, the mold was placed in an oven, and the temperature was raised from 40 ° C to 100 ° C.
The temperature was raised over 9 hours, and the temperature was maintained at 100 ° C. for 1 hour to perform thermal polymerization. Thereafter, the tape was removed and the mold was released to obtain a molded product.

(Example 2) Adhesive tape composed of a polyethylene terephthalate base material (thickness 30 μm) and a glue containing fluorosilicone rubber as a main polymer (glue thickness 30 μm)
Styrene and 40 parts by weight of 2,2-bis [3,5-dibromo-4- (2-methacryloyloxyethoxy) phenyl] propane 60 are placed in a space formed by fixing two glass molds using a mold. A mixture obtained by adding 1.0 part by weight of tert-butyl peroxy neodecanoate to parts by weight was injected. Next, the mold was placed in an oven, heated from 30 ° C. to 90 ° C. over 17 hours, and kept at 90 ° C. for 3 hours to perform thermal polymerization. Thereafter, the tape was removed and the mold was released to obtain a molded product.

Example 3 An adhesive tape made of a polyethylene terephthalate base material (thickness: 40 μm) and a glue containing methyl vinyl silicone rubber as a main polymer (glue thickness: 30 μm) was used. In a space formed by fixing two glass molds, 29 parts by weight of dicyclohexylmethylene diisocyanate, 29 parts by weight of isophorone diisocyanate, and 4-mercaptomethyl-3,6-dithia-1,8 A mixture obtained by adding 0.05 parts by weight of dimethyltin dichloride and 0.03 parts by weight of N, N-dimethylcyclohexylamine to 42 parts by weight of octanedithiol was injected. Next, the mold was placed in an oven, heated from 30 ° C. to 130 ° C. over 9 hours, and kept at 130 ° C. for 3 hours to perform thermal polymerization. Thereafter, the tape was removed and the mold was released to obtain a molded product.

(Comparative Example 1) In Example 1, the thickness of the glue containing methyl vinyl silicone rubber as the main polymer was 1
A molded product was obtained in the same manner as in Example 1 except that the thickness was 0 μm.

Comparative Example 2 A molded article was obtained in the same manner as in Example 2 except that the thickness of the polyethylene terephthalate substrate was changed to 70 μm.

(Comparative Example 3) In Example 3, the thickness of the glue containing methyl vinyl silicone rubber as the main polymer was 4
A molded product was obtained in the same manner as in Example 3 except that the thickness was 0 μm.

In each of the above Examples and Comparative Examples, 10 sheets were polymerized, and the degree of chipping was evaluated by the following method.

(Good product standard) A depth of 3.0 mm or less in the center direction and a length of 4.0 mm or less in the outer peripheral direction are acceptable. Or
2.0mm or less in depth in center direction, 3.0mm in length in outer circumference direction
The following two points are acceptable. Alternatively, up to 8 pieces of cloth with a diameter of 1.5 mm or less are acceptable.

[0024]

[Table 1]

[0025]

As described above, according to the present invention, even if a slow-curing composition containing a monomer having an allyl group, a vinyl group or an isocyanate group is used, a plastic lens which is not chipped can be produced. can do.

Claims (4)

[Claims] A first step of fixing two molds using an adhesive tape; a liquid curable composition in a space formed by the two molds and the adhesive tape; And a third step of curing and molding the liquid curable composition in this order, wherein the adhesive has a paste thickness of 20 to 35 μm and a tape. Base material thickness is 10
A method for producing a plastic lens, wherein the first step is performed using an adhesive tape having a thickness of from 60 to 60 μm. 2. The method of manufacturing a plastic lens according to claim 1, wherein said adhesive is a silicone-based adhesive. 3. The method of manufacturing a plastic lens according to claim 1, wherein the base material of the adhesive tape is polyethylene terephthalate. 4. The method for producing a plastic lens according to claim 1, wherein the liquid curable composition contains a monomer having an allyl group, a vinyl group or an isocyanate group. Characteristic method of manufacturing plastic lenses.