JP2006240210A - Manufacturing method of plastic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a plastic lens capable of preventing generation of a tape wrinkle in a tape molding method. <P>SOLUTION: The manufacturing method of the plastic lens L1 comprises a mold-assembling process of winding an adhesive tape 4 having a 125 μm to 200 μm thick tape-like base material and an adhesive layer formed on the tape-like base material around a side surface of two molding molds 2 and 3, both being face to face arranged spaced apart at a predetermined interval, to fix the molding molds 2 and 3 and make a cavity 5 surrounded by the two molding molds 2 and 3 and the adhesive tape 4; an injecting process of injecting a lens material M in the cavity 5; and a superposition and curing process for curing the lens material M. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a plastic lens, and more particularly to a method for manufacturing a plastic lens in which a plastic lens is molded by a casting polymerization method.

  When producing a plastic lens having excellent optical performance, a casting polymerization method is generally used. As a casting polymerization method, a molding mold for molding the convex surface of the lens and a molding mold for molding the concave surface of the lens are opposed to each other at a predetermined interval, and a molding mold in which the outer peripheral side surface of the molding mold is sealed with an adhesive tape, A tape mold method in which a raw material composition is injected and polymerized and cured is widely known (see FIG. 1).

  The raw material composition injected into the molding mold shrinks in volume upon polymerization and curing. In particular, with the recent increase in the refractive index of lenses, raw material compositions having an increasing shrinkage rate are being used. Therefore, as shown in the cross-sectional view of the conventional polymerization mold that has been polymerized and cured in FIG. 2A, the distance between the molds 12 and 13 is determined during the polymerization and curing of the mold 11 into which the raw material composition M has been injected. A force for narrowing is transmitted to the pressure-sensitive adhesive tape 14, and the pressure-sensitive adhesive tape 14 is crushed in the thickness direction of the molding mold 11, thereby generating a large number of partially wrinkled tape wrinkles 15. As shown in the side view of the molded conventional plastic lens in FIG. 2B, the tape wrinkle 15 is transferred as it is to the side surface of the outer periphery of the plastic lens L2, and a large number of dents 16 are generated. The recess 16 formed on the side surface of the outer periphery of the plastic lens L2 becomes conspicuous as the thickness A (edge thickness) of the side surface of the plastic lens L2 increases, and the outer periphery of the lens is deteriorated. It is removed by the outer periphery shaping process.

  In order to deal with such tape wrinkles, a plastic lens manufacturing method that suppresses the occurrence of tape wrinkles on the side of the lens by using an adhesive tape that easily stretches at a temperature where the shrinkage due to polymerization and curing of the raw material composition is the largest is proposed. (For example, refer to Patent Document 1).

JP 2004-202995 A

  However, the plastic lens produced by the manufacturing method disclosed in Patent Document 1 is not sufficient although the generation of tape wrinkles is somewhat improved, and it still requires an outer periphery shaping process to remove the dents on the side surfaces of the lens. For this reason, it is necessary to form the outer diameter of the mold used in the casting polymerization method to be about 5 mm larger than the finished outer diameter of the plastic lens. Therefore, there is a problem that the raw material composition removed by the outer periphery shaping process is wasted, resulting in an increase in manufacturing cost and a decrease in yield due to generation of defects such as scratches on the lens surface due to an increase in processing steps. Furthermore, there is a problem of generating plastic waste.

  Then, this invention is made | formed in view of such a situation, and it aims at providing the manufacturing method of the plastic lens which can suppress generation | occurrence | production of the tape wrinkle in a tape mold method (casting polymerization method). .

  In order to solve the above-described problems, the plastic lens manufacturing method of the present invention is configured to fix the mold by winding an adhesive tape around the side surfaces of two molds arranged to face each other at a predetermined interval. A mold assembly process for forming a cavity for molding a lens surrounded by a mold and the adhesive tape, an injection process for injecting a raw material composition into the cavity, and a polymerization to obtain a plastic lens by polymerizing and curing the raw material composition In the method for producing a plastic lens having a curing step, the pressure-sensitive adhesive tape has a structure in which a pressure-sensitive adhesive layer is formed on a tape-shaped substrate, and the substrate thickness of the tape-shaped substrate is 125 μm to 200 μm. It is characterized by.

  According to this method for producing a plastic lens, a raw material composition is injected into a cavity in which an adhesive tape having a thickness of a tape-shaped substrate of 125 μm to 200 μm is wound around the side surfaces of two molding dies, polymerized and cured. When molded, it can withstand shrinkage of the raw material composition during polymerization and curing without being crushed by a force that tends to narrow the distance between the molds in the thickness direction, and suppresses the occurrence of tape wrinkles of the adhesive tape. It becomes possible, and by using a molding die having an outer diameter substantially the same as the finished outer diameter of the plastic lens, the outer periphery shaping to be finished to the finished outer diameter becomes unnecessary.

  In other words, in addition to reducing the amount of raw material composition used, environmentally friendly cutting powder (waste) is reduced, exhaust gas generated during combustion processing of cutting dust, or scratches on the lens surface due to increased processing steps, etc. Such an effect can be obtained that yield reduction can be prevented by the occurrence of defects. Therefore, due to these effects, an inexpensive plastic lens with reduced manufacturing costs can be provided to the market.

  The method for producing a plastic lens of the present invention is characterized in that the tape-shaped substrate is any one of polyvinyl halide, polyester, polyamides, polyimides, and polycarbonates.

  According to this plastic lens manufacturing method, the tape-shaped substrate is made of any one of polyvinyl halide, polyester, polyamides, polyimides, and polycarbonates, and the thickness of the tape-shaped substrate is set to 125 μm to 200 μm. Therefore, when it is molded by polymerization and curing, it can withstand the force of shrinking the raw material composition to narrow the distance between the molds in the thickness direction without being crushed, and the occurrence of tape wrinkles on the adhesive tape Can be sufficiently suppressed, and by using a molding die having an outer diameter that is substantially the same as the finished outer diameter of the plastic lens, it is not necessary to perform outer periphery shaping to process the finished outer diameter.

Embodiments of the present invention will be described below.
First, the tape molding method will be described with reference to FIG. FIG. 1A is a schematic external view of a molding mold, FIG. 1B is a cross-sectional view of the molding mold before injection of the lens material, and FIG. 1C is a side view of the molded plastic lens. FIG.

When molding a plastic lens, the molding mold 1 is assembled in a molding die assembling process.
The molding mold 1 prepares a circular glass mold 2 that molds the convex surface of a plastic lens (hereinafter referred to as a lens) and a circular glass mold 3 that molds the concave surface of the lens. The outer diameters of these two molds 2 and 3 are determined in consideration of the amount of contraction that the lens raw material M as the raw material composition injected into the molding mold 1 contracts in the radial direction during polymerization and curing. It is set to be approximately 1 mm larger than the finished outer diameter of the lens.

  Then, the two molds 2 and 3 are arranged opposite to each other in a predetermined gap, and the adhesive tape 4 is wound a little more than one turn around the side surfaces of the molds 2 and 3 to fix the molds 2 and 3. A gap 5 between the molds 2 and 3 is closed to form a cavity 5 surrounded by the molding surfaces of the molds 2 and 3 and the adhesive tape 4.

  The adhesive tape 4 has a structure in which an adhesive layer is formed on a tape-like substrate. The tape-shaped substrate has sufficient strength to hold the two molds 2 and 3, and has chemical resistance that is not affected by the liquid lens material M, and also has sufficient heat resistance against heating during polymerization and curing. The material of the tape base material is polyolefin such as polyethylene and polypropylene, polyvinyl halide such as polyvinyl chloride and polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. Examples thereof include polyesters, polyamides, polyimides, and polycarbonates. Of these, polyethylene terephthalate can be preferably used. Moreover, as an adhesive, the adhesive applied to common adhesive tapes, such as an acrylic type, a rubber type, and a silicone type, is mentioned.

  The thickness of the tape base material is 100 μm to 220 μm, preferably 125 μm to 200 μm, having sufficient strength to hold the two molds 2 and 3 and having resistance (rigidity) against shrinkage of the lens raw material during polymerization curing. The range is used. When the thickness is 100 μm or less, the strength of the tape base material cannot withstand the shrinkage of the lens raw material at the time of polymerization curing, and a large number of partially wrinkled tape wrinkles are generated (see FIG. 2A). ). When the thickness is 220 μm or more, the workability of wrapping around the side surfaces of the molds 2 and 3 is remarkably lowered, and liquid leakage occurs from the overlapping portion wound slightly more than one round, and bubbles are generated in the molded lens. There is a case. The pressure-sensitive adhesive tape 4 has a pressure-sensitive adhesive layer having a thickness of about 30 μm formed on a tape base material having a width of about 25 mm.

Next, in the molding mold 1 assembled in the mold assembly process, the lens raw material M as the raw material composition is injected in the injection process.
In the injection process, first, compressed air heated by an air heater is blown through a metal nozzle to a predetermined position of the adhesive tape 4 affixed to the outer peripheral side surfaces of the molds 2 and 3 to form a lens raw material. An injection port (not shown) for injection is formed. Then, the lens material M is injected into the cavity 5 from the injection port via the injection nozzle.

  The lens raw material is not particularly limited, and examples thereof include diethylene glycol bisallyl carbonate (CR-39). Further, as a lens material for a high refractive index, a material mainly composed of a polymerizable monomer mainly composed of a polyisocyanate having two or more isocyanate groups and a compound having two or more active hydrogens. It can be illustrated.

Examples of the polyisocyanate having two or more isocyanate groups include m-xylylene diisocyanate, p-xylylene diisocyanate, tetrachloro-m-xylylene diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenation. Diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, 2,5-bis (isocyanatomethyl) bicyclo [2.2.1] heptane, 2,6-bis (isocyanatomethyl) bicyclo [2.2.1] Heptane, 3,8-bis (isocyanatomethyl) tricyclo [5.2.1.0 ^2.6 ] -decane, 3,9-bis (isocyanatomethyl) tricyclo [5.2.1.0 ^2.6 ] -decane, 4,8-bis (isocyanatomethyl) tricyclo [5.2.1.0 ^2.6] - decane, 4,9 Scan (isocyanatomethyl) tricyclo [5.2.1.0 ^2.6] - decane, polyisocyanate compounds such as dimer acid diisocyanate and allophanate-modified products of these compounds, 1,3-bis (alpha, alpha- Dimethylisocyanatomethyl) benzene, 1,4-bis (α, α-dimethylisocyanatomethyl) benzene, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate Narate, tolidine diisocyanate, naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, biuretation reaction product of hexamethylene diisocyanate, adduct formation of hexamethylene diisocyanate and trimethylolpropane Products, 4,4′-dicyclohexylmethane diisocyanate, modified isocyanurate, etc., and these compounds can be used alone or in admixture of two or more.

  Examples of the compound having two or more active hydrogens include a polyol having two or more hydroxyl groups, a polythiol having two or more thiol groups, and a compound having one or more hydroxyl groups and thiol groups in each molecule. Can be mentioned.

  Examples of polyols having two or more hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, butane triol, and 1,2-methyl. Glucoside, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, erythritol, threitol, ribitol, arabinitol, xylitol, allitol, mannitol, dorscitol, iditol, glycol, inositol, hexanetriol, triglycerol, diglycerol, triethylene glycol, Polyethylene glycol, tris (2-hydroxyethyl) isocyanur , Cyclobutanediol, cyclopentanediol, cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo [5,2,1,0,2,6] decane-dimethanol, bicyclo [4,3,0] -nonanediol, dicyclohexanediol, tricyclo [5,3,1,1] dodecanediol, bicyclo [4,3,0] nonanedimethanol, tricyclo [5,3,1,1] Dodecane-diethanol, hydroxypropyltricyclo [5,3,1,1] dodecanol, spiro [3,4] octanediol, butylcyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, maltitol, lactito Dihydroxynaphthalene, trihydroxynaphthalene, tetrahydroxynaphthalene, dihydroxybenzene, benzenetriol, biphenyltetraol, pyrogallol, (hydroxynaphthyl) pyrogallol, trihydroxyphenanthrene, bisphenol A, bisphenol F, xylylene glycol, Aromatic polyols such as tetrabromobisphenol A, di- (2-hydroxyethyl) sulfide, 1,2-bis- (2-hydroxyethyl mercapto) ethane, bis (2-hydroxyethyl) disulfide, 1,4-dithiane 2,5-diol, bis (2,3-dihydroxypropyl) sulfide, tetrakis (4-hydroxy-2-thiabutyl) methane, tetrabromobisphenol S, teto Examples include polyols containing sulfur atoms such as methyl bisphenol S, 4,4′-thiobis (6-tert-butyl-3-methylphenol), 1,3-bis (2-hydroxyethylthioethyl) -cyclohexane. .

  Examples of polythiol having two or more thiol groups include 4-mercaptomethyl-3,6-dithio-1,8-octanedithiol, pentaerythritol tetrakis (3-mercaptopropionate), and tetrathiol. be able to.

  Examples of the compound having one or more hydroxyl groups and thiol groups in one molecule include 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerol di (mercaptoacetate), 1-hydroxy-4- Mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3 -Butanediol, pentaerythritol tris (3-mercaptopropionate), pentaerythritol mono (3-mercaptopropionate), pentaerythritol bis (3-mercaptopropionate), pentaerythritol tris (thioglycolate) Pentaerythritol pentakis (3-mercaptopropionate), hydroxymethyl-tris (mercaptoethylthiomethyl) methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene, 4-hydroxy-4'-mercaptodiphenylsulfone, 2 Examples include-(2-mercaptoethylthio) ethanol, dihydroxyethyl sulfide mono (3-mercaptopropionate), dimercaptoethane mono (sulcylate), hydroxyethylthiomethyltris (mercaptoethylthio) methane, and the like.

  Further, as other raw material compositions for high refractive index, compounds having one or more disulfide bonds (SS) in the molecule and having an epoxy group and / or a thioepoxy group can be exemplified. .

  A polymerization catalyst can be blended with these polymerizable compositions. Examples of the polymerization catalyst include urethanization reaction catalysts such as dibutyltin dilaurate, dibutyltin dichloride, tin compounds such as dimethyltin dichloride, amine compounds such as tertiary amines, tertiary phosphines, and Lewis acids. It can be used alone or in combination. In addition, various chain extenders, crosslinkers, light stabilizers, UV absorbers, antioxidants, anti-coloring agents, bluing agents, dyes, pigments, leveling agents, fillers, internal release agents, etc., as necessary Can be added.

  Next, in the molding mold 1 into which the lens material M has been injected in the injection process, the lens material M is polymerized and cured in the polymerization and curing process. Polymerization curing is performed by heating the lens material M in the mold part 5. The molding mold 1 is placed in a heating furnace and, for example, the temperature in the furnace is gradually raised from 30 ° C. to 120 ° C. over about 20 hours, and is cured by polymerization.

  In this polymerization curing step, the lens material M injected into the molding mold 1 undergoes shrinkage due to polymerization. Since the cavity 5 has a long dimension in the radial direction and a short dimension in the thickness direction, the shrinkage amount in the radial direction of the lens material M is large, and the adhesive tape constituting the cavity tends to be sucked to the center side. The distance between the molds 2 and 3 tends to be narrowed, but due to the rigidity of the adhesive tape 4 (tape base material), the distance between the molds 2 and 3 is not narrowed, and tape wrinkles are not generated. .

Thereafter, the molding mold 1 peels the adhesive tape 4 from the molding dies 2 and 3 and removes the molding dies 2 and 3 to obtain a plastic lens L1.
The molded plastic lens L1 is corrected for the outer diameter shrinkage, and a plastic lens L1 having a predetermined outer diameter size, a substantially flat side surface, and a predetermined lens core thickness (lens center thickness) is obtained. .

  In the plastic lens, the molding surfaces of the two molding dies are formed on the final optical surface, and the final lens is transferred only on the molding surface of one of the two molding dies. There is a slightly thicker semi-finished lens that is formed by polishing or the like on the molding surface side that has an optical surface and does not have the other optical characteristics, and there are convex lenses and concave lenses, etc. Can be applied as well.

  Examples and comparative examples based on this embodiment will be described below.

(Example)
A lens raw material M is injected into each molding mold 1 assembled using two types of adhesive tapes 4 having a tape base material thickness of 125 μm and 200 μm, an outer diameter of 75 mm, a lens core thickness of 1.0 mm, A diopter plastic lens L1 having a spherical power (S power) of -4.0 is molded. The plastic lens L1 is formed by completing 100 sheets for each thickness of the tape base material.

  First, two molds 2 and 3 made of glass having an outer diameter of 76 mm were prepared. For the dimensional difference of 1 mm between the lens outer diameter and the outer diameter of the mold, the outer diameters of the molds 2 and 3 were set to be 1 mm larger in advance in order to correct the outer diameter shrinkage due to polymerization hardening of the lens raw material.

  And the lens raw material M inject | poured into the molding mold 1 was prepared. The lens raw material M is a polythiol compound 4-mercaptomethyl-3,6-dithio-1,8-octanedithiol 40 g as a raw material composition, 0.06 g dimethyltin dichloride as a polymerization catalyst, 0.15 g internal release agent, Add 0.1 g of 2- (2-hydroxy-5-tert-octylphenyl) -2H-benzotriazole as an ultraviolet absorber and 0.04 g of N, N-dimethylcyclohexylamine as a polymerization catalyst in this order for 30 minutes. Stir well enough. Thereafter, 60 g of hydrogenated diphenylmethane diisocyanate was mixed as a polyisocyanate compound, and after sufficiently stirring for about 30 minutes, deaeration was performed under a vacuum of 5 mmHg for 60 minutes.

  Then, the process proceeds to the molding die assembling process, the two prepared molding dies 2 and 3 are arranged to face each other, and the distance between the central portions of the molding dies 2 and 3 is kept at 1.0 mm. , 3 was wound around the side surface of the adhesive tape 4 with a thickness of 200 μm a little more than one turn to assemble the molding mold 1. Similarly, a molding mold 1 having a tape substrate thickness of 125 μm was assembled.

  And it transfers to an injection | pouring process, drills in the predetermined position of the adhesive tape 4 affixed on the outer peripheral side surface of the shaping | molding die 2 and 3 of each mold 1 for assembling, and inject | pours the lens raw material M An inlet was formed. Thereafter, the prepared lens material M was injected into the cavity 5 from the formed injection port via the injection nozzle. The amount of lens raw material M injected into each mold 1 (cavity 5) was 20.5 g.

Then, the process proceeds to the polymerization curing step, each molding mold 1 into which the lens raw material M is injected is placed in a heating furnace, and the temperature in the furnace is gradually increased from 30 ° C. to 120 ° C. over about 20 hours. The lens raw material M injected into each mold 1 was polymerized and cured.
Then, after each mold 1 is cooled, the mold 1 is taken out from the heating furnace, the two molds 2, 3 and the adhesive tape 4 are removed, and a high refractive index plastic lens having a refractive index of 1.67. L1 was obtained. The obtained plastic lens L1 had an outer diameter of 75 mm, a lens core thickness of 1.0 mm, and the lens side surface was almost flat and smooth.

(Comparative example)
The lens raw material M is injected into each molding mold 1 assembled using three types of adhesive tapes 4 having a thickness of 38 μm, 50 μm, and 75 μm, and the outer diameter is 75 mm. A diopter plastic lens having a lens core thickness of 1.0 mm and a spherical power (S power) of -4.0 is molded. In addition, as for the molding of the plastic lens, 100 sheets are completed for each thickness of each tape base material as in the embodiment.

For molding of the plastic lens, two molds 2 and 3 made of glass having an outer diameter of 80 mm were prepared on the assumption of shrinkage due to polymerization of the lens raw material M injected into the molding mold.
Then, the process proceeds to the mold assembling step, the prepared two molds 2 and 3 are made to face each other, and the center portion is maintained at a distance of 1.2 mm assuming shrinkage due to polymerization. Three types of adhesive tapes 4 having a tape substrate thickness of 38 μm, 50 μm, and 75 μm were wound around the side surface, and three types of molding molds 1 having different tape substrate thicknesses were assembled.

  And it transfers to an injection | pouring process, forms an injection port in the predetermined position of the adhesive tape 4 affixed on the outer peripheral side surface of the two shaping | molding dies 2 and 3 similarly to an Example, and the formed injection port The lens material M prepared from the above was injected. The amount of lens raw material M injected into each mold 1 (cavity 5) was 24.1 g.

  Then, the polymerization hardening process was carried out, and each molding mold 1 into which the lens raw material M was injected was polymerized and cured under the same polymerization conditions and polymerization method as in the examples. After that, after each molding mold 1 is cooled, the molding mold 1 taken out from the heating furnace has a large number of tape wrinkles 15 that are partially dented by the adhesive tape 4 affixed to the side surface being crushed in the thickness direction. (See FIG. 2 (a)).

  Then, the two molding dies 2 and 3 and the adhesive tape 4 are removed, and the obtained plastic lens has an outer diameter of 80 mm, a lens core thickness of 1.0 mm, and a large number of dents 16 on the side surface (FIG. 2 ( It was a high refractive index plastic lens having a refractive index of 1.67. That is, in the obtained plastic lens, the adhesive tape 4 attached to the side surface is crushed by about 0.2 mm in the thickness direction due to contraction of the lens raw material M at the time of polymerization and curing, and the tape wrinkle 15 (see FIG. 2 (a)) occurs, and it is estimated that a large number of dents 16 are formed on the side surface of the molded lens. The depth of the dent 16 generated on the side surface is about 2 to 3 mm for the large dent 16, and thereafter, the dent 16 is removed by outer peripheral shaping, and the lens is shaped to 75 mm, which is the finished outer diameter of the lens.

  In addition, the crushing state of the semi-finished lens having a thick edge when polymerized and cured was experimentally confirmed. When molding a semi-finished lens having a lens core thickness of 7.0 mm, molding is performed using two adhesive molds 2 and 3 made of glass having an outer diameter of 80 mm and an adhesive tape 4 having a tape substrate thickness of 75 μm. A mold 1 was assembled. A lens raw material M similar to that of the example was injected into the assembled mold 1 for polymerization and curing. The obtained plastic lens has a lens core thickness of 0.4 mm with respect to the interval between the two molds 2 and 3 assembled by the molding mold 1 being crushed in the thickness direction by contraction of the lens raw material M. Molded thinly.

The occurrence of dents on the side surfaces of the 100 plastic lenses obtained in the above examples and comparative examples was visually confirmed. The confirmation was classified into three ranks as shown below. The results are shown in Table 1.
○: A lens with no dents.
Δ: A lens having a partial depression.
X: A lens with a dent on the entire circumference.

表１より、成形用モールド１を形成する粘着テープ４のテープ基材の厚さが、１２５μｍ〜２００μｍの粘着テープ４を用いることにより、成形モールド１に注入されたレンズ原料Ｍの重合硬化時におけるテープシワの発生を顕著に抑制したプラスチックレンズの製造方法が得られる。

From Table 1, the thickness of the tape base material of the adhesive tape 4 that forms the molding mold 1 is 125 μm to 200 μm in thickness, so that the lens raw material M injected into the molding mold 1 is polymerized and cured. A method for producing a plastic lens in which the occurrence of tape wrinkles is remarkably suppressed is obtained.

According to the plastic lens manufacturing method of the above-described embodiment, it is possible to mold with a molding die having a lens finished outer diameter size of +1 mm, and the outer peripheral shaping process is not required, thereby obtaining the following effects. It is done.
(A) Reduction of the amount of plastic lens raw material M used; about 13%.
(B) Reduction of peripheral cutting powder (waste); about 13%.
(C) Reduction of exhaust gas generated during combustion processing of cutting powder; 13%.
(D) Reduction of the amount of glass raw material used in the mold; about 11%.
(E) Reduction of the amount of adhesive tape 4 used; about 5%.
(F) No peripheral shaping apparatus is required.
(G) Reduction in the amount of M / C power used due to the necessity of the outer periphery shaping process, improvement in yield due to the absence of scratches on the molded lens surface, and the like.

  Therefore, due to these effects, an inexpensive plastic lens with reduced manufacturing costs can be provided to the market. In particular, with the recent increase in the refractive index of plastic lenses, the polymerization shrinkage of the plastic lens raw material becomes larger and more expensive, and the plastic lens raw material has a great saving effect.

(A) is a schematic external view of a molding mold, (b) is a cross-sectional view of the molding mold before injection of lens raw materials, and (c) is a side view of a molded plastic lens. (A) is sectional drawing of the conventional mold for polymerization hardening, (b) is a side view of the conventional plastic lens shape | molded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Mold for molding, 2, 3, 12, 13 ... Mold, 4, 14 ... Adhesive tape, 5 ... Cavity, 15 ... Tape wrinkle, 16 ... Depression, M ... Lens raw material as raw material composition, L1, L2: Plastic lens.

Claims (2)

Adhesive tape is wound around the side surfaces of two molding dies arranged opposite to each other at a predetermined interval to fix the molding dies, thereby forming a cavity for molding a lens surrounded by the two molding dies and the adhesive tape. In a plastic lens manufacturing method comprising: a mold assembly step; an injection step of injecting a raw material composition into the cavity; and a polymerization curing step of polymerizing and curing the raw material composition to obtain a plastic lens.
The said adhesive tape has a structure in which the adhesive layer was formed on the tape-shaped base material, and the base material thickness of the said tape-shaped base material is 125 micrometers-200 micrometers, The manufacturing method of the plastic lens characterized by the above-mentioned. In the manufacturing method of the plastic lens of Claim 1,
The method for producing a plastic lens, wherein the tape-shaped substrate is any one of polyvinyl halide, polyester, polyamides, polyimides, and polycarbonates.

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