JP3126850B2 - Plastic lens mold and method of manufacturing plastic lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic lens mold and a method for producing a plastic lens.

[0002]

2. Description of the Related Art Diethylene glycol bisallyl carbonate is widely used as a monomer for producing a plastic lens by a cast polymerization method. Furthermore, for the casting polymerization of diethylene glycol bisallyl carbonate, a lens mold (sometimes referred to as a mold or simply called a mold) made of glass or metal, a soft vinyl chloride resin or ethylene-vinyl acetate (EVA) is used. A mold made of a resin and a gasket (sometimes called a spacer) made of a soft resin such as an ethylene-ethyl acrylate resin is used.

Meanwhile, plastic lenses made of diethylene glycol bisallyl carbonate are widely used because they are lightweight, have good impact resistance, and are easy to dye. However, in addition to diethylene glycol bisallyl carbonate, high refractive index plastic lenses and low specific gravity plastic lenses have recently been developed. As monomers for these lens materials, aromatic monomers and acrylate and methacrylate monomers are used.

[0004]

Therefore, an attempt has been made to cast-polymerize these aromatic monomers and acrylate and methacrylate monomers. However,
When these monomers are cast-polymerized using a gasket made of a soft resin such as the above-mentioned soft vinyl chloride resin, the material of the gasket itself and the plasticizer contained therein are reduced in a single amount during the polymerization. Elutes in the body. As a result, the produced plastic lens often becomes cloudy or causes striae, and there is a problem that it is difficult to obtain a good lens.

In order to solve such a problem, it has been proposed to cast and polymerize an aromatic monomer using a gasket containing a fluorine-containing elastomer (Japanese Patent Laid-Open No. 60-112408). issue). However, the method specifically disclosed in this publication is to prepare a gasket by applying an EVA resin or the like with a fluorine-containing elastomer as described in Examples. Therefore, this method has a problem that productivity is low and cost is high.

Accordingly, an object of the present invention is to provide an aromatic monomer or an acrylate or methacrylate monomer without causing elution or the like, and for casting polymerization of these monomers.
An object of the present invention is to provide a plastic lens molding mold including a gasket which can be favorably used and is easy to manufacture.

Another object of the present invention is to provide a method for producing a plastic lens having good optical properties by molding an aromatic monomer or an acrylate or methacrylate monomer by cast polymerization. It is in.

[0008]

Means for Solving the Problems The present inventors diligently studied a mold for forming a plastic lens and a method of manufacturing a plastic lens which do not cause the above-mentioned problems.
As a result, by using a gasket made of a thermoplastic polyurethane elastomer for casting polymerization of aromatic monomers or acrylate or methacrylate monomers,
The inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention relates to a mold comprising a gasket and a molding die, wherein the gasket is made of a thermoplastic polyurethane elastomer.

Further, the present invention relates to a method for producing a plastic lens, which comprises injecting a liquid containing a monomer into the mold and then polymerizing the monomer to obtain a plastic lens.

The plastic lens mold of the present invention basically comprises a gasket and a mold. The gasket is generally ring-shaped or cylindrical in shape, and the opening of the gasket is closed from above and below with two molding dies to form a mold. However, in the present invention, the shapes and structures of the gasket and the molding die are not particularly limited. Furthermore, the mold of the present invention is not intended to consist only of a gasket and a mold, and does not exclude having other parts and functions, such as a monomer injection port.

The shape and structure that the plastic lens molding mold of the present invention can have are, for example, those described in Japanese Utility Model Application Laid-Open No. 55-13 / 55.
No. 4224, No. 2-127413, No. 3-2
No. 6517 and Japanese Utility Model Publication No. 3-31538. However, these are only examples, and the present invention is not limited to these.

A feature of the present invention is that the gasket is formed from a thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer is structurally composed of, for example, a soft segment composed of polymeric glycol, a monomolecular chain extender constituting a hard segment, and diisocyanate. The types and amounts of the polymer glycol, the monomolecular chain extender and the diisocyanate can be appropriately changed depending on the shape of the gasket, the type of the monomer for the plastic lens, and the like. Further, the kind of the monomer used for the gasket is determined in consideration of flexibility, heat resistance, chemical resistance and the like.

Polymeric glycol is a high molecular polyol, and examples of polyester as the high molecular polyol include EA (ethylene adipate), BA (butylene adipate) or a copolymer thereof, PLC (polycaprolactone), HA and the like. And copolymers with neopentyl adipate. The molecular weight of the high molecular polyol is usually about 1,000 to 2,000. Further, a polyether polyol can also be used.

Examples of active hydrogen compounds which are monomolecular chain extenders include alkylene glycols, polyalkylene glycols, poly (alkylene adipates), poly-ε-caprolactones, polybutadiene glycols, poly (alkylene carbonate). ), And polyols such as silicone polyol.

Examples of polyisocyanates such as diisocyanate include tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalenediisocyanate,
Aromatic diisocyanates such as 3,3'-dimethyl-4,4'-diphenyl diisocyanate; 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,3-bis (isocyanate And aliphatic diisocyanates such as (natomethyl) cyclohexane and trimethylhexamethylene diisocyanate. Further, as polyisocyanate, hydrogenated xylylene diisocyanate; biuret conjugate of hexamethylene diisocyanate or isocyanurate conjugate; reaction adduct of hexamethylene diisocyanate with trimethyl propane described in JP-A-61-114203. ;
2-isocyanatoethyl-2,6-diisocyanate hexanoate; 1,6,11-undecane triisocyanate; a reaction adduct of isophorone diisocyanate with trimethylolpropane; a reaction adduct of xylylene diisocyanate with trimethylolpropane;
A so-called block type polyisocyanate such as a reaction adduct of bis (isocyanatomethyl) cyclohexane with trimethylolpropane is also included.

The gasket used in the mold of the present invention is obtained by molding the thermoplastic polyurethane elastomer into a desired shape by a conventional method. There are various gasket molding methods. For example, the gasket can be easily obtained by injection molding. Further, since the gasket used in the present invention can be injection-molded, there is an advantage that productivity is good.

Next, a method for manufacturing a plastic lens using the molding mold of the present invention will be described.

The production method of the present invention can be applied to a wide range of monomers including those used in the production of conventional plastic lenses. However, the production method of the present invention is particularly effective for aromatic monomers, acrylates, and methacrylate monomers, which did not produce good plastic lenses using conventional gaskets. .

Examples of such a monomer include aromatic monomers such as styrene, methylstyrene, chlorostyrene, divinylbenzene, phenyl methacrylate, benzyl methacrylate and diallyl phthalate, acrylic acid, methyl acrylate, ethyl acrylate, and the like. Acrylates such as ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol ethane triacrylate, tetramethylol methane tetraacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylol ethane trimethacrylate, tetramethylol And methacrylates such as methanetetramethacrylate.

In the present invention, a liquid containing a monomer is injected into a mold made of a thermoplastic polyurethane elastomer formed into a predetermined shape and a plastic lens molding die made of glass or metal. I do. In addition to a monomer, a radical polymerization initiator and, if necessary, known additives such as an ultraviolet absorber and a light stabilizer can be appropriately added to this liquid. The radical polymerization initiator to be used is appropriately determined in consideration of the type of the monomer to be used and the like. Examples of the radical polymerization initiator include peroxides such as methyl ethyl ketone peroxide and azo compounds such as 1,1′-azobis (cyclohexane-1-carbonitrile).

After injecting the liquid containing the monomer into the mold, polymerization is carried out by a conventional method such as heating or irradiation with ultraviolet rays. For example, a method in which the temperature is gradually raised from around room temperature to 120 ° C. to carry out polymerization, a method in which gelation is carried out at a certain temperature in advance to some extent, and then the temperature is raised to carry out polymerization, and the like can be given. However, the conditions and the like for producing a plastic lens using the molding mold of the present invention can be appropriately determined depending on the types and amounts of the monomer to be polymerized and the polymerization initiator. For example, JP-A-54-4196
No. 5, JP-A-61-83212, etc. can be referred to.

[0023]

EXAMPLES The present invention will be further described below with reference to examples.
All parts in the examples are parts by weight. Example 1 Adipate-based polyurethane E185 manufactured by Nippon Miractran Co., Ltd. as a thermoplastic polyurethane elastomer
Using PNAT, a casting gasket was prepared by injection molding using a mold set to be 0.00 diopter in diethylene glycol bisallyl carbonate. Further, in the case of diethylene glycol bisallyl carbonate, a lens molding mold was prepared in combination with two glass molds set so as to obtain a lens of 0.00 diopter.

Then, 60 parts of styrene, 40 parts of 2,2-bis [4- (2-methacryloyloxyethoxy) phenyl] propane, and Tinuvin PS as an ultraviolet absorber were used.
0.05 parts (manufactured by Ciba-Geigy) and 1.5 parts of lauroyl peroxide as a polymerization initiator were mixed and stirred to obtain a monomer mixture for lenses. The monomer mixture was poured into the lens molding mold, and the temperature was gradually raised from 40 ° C. to 85 ° C. over 21 hours to carry out polymerization. After the completion of the polymerization, the lens was taken out of the mold and further subjected to a heat treatment at 120 ° C. for 1 hour to remove distortion due to the polymerization to obtain a lens. The obtained lens was free from fogging and excellent in transparency, and was applicable to optical applications.

Example 2 As a monomer mixture, 80 parts of methyl methacrylate, 20 parts of ethylene glycol dimethacrylate, Tinuvin PS
Example 1 was repeated except that 0.05 parts and 0.3 part of 2,2'-azobisisobutyronitrile were used as a polymerization initiator. The obtained lens was free from fogging and excellent in transparency.

Example 3 As a gasket material, E590P which is a thermoplastic polyurethane of a polycarbonate ester manufactured by Nippon Miractran Co., Ltd.
The procedure was performed in the same manner as in Example 1 except that NAT was used. All the obtained lenses were free from fogging and excellent in transparency, and were applicable to optical applications.

Example 4 As a gasket material, caprolactone-based thermoplastic polyurethane E995PN manufactured by Nippon Milactran Co., Ltd.
The procedure was performed in the same manner as in Example 2 except that AT was used. All the obtained lenses are excellent in transparency without fogging,
It could be applied to optical applications.

Example 5 As a gasket material, P590MN, a caprolactone-based thermoplastic polyurethane manufactured by Nippon Milactran Co., Ltd.
The procedure was performed in the same manner as in Example 1 except that AT was used. All the obtained lenses are excellent in transparency without fogging,
It could be applied to optical applications.

Comparative Example 1 The procedure of Example 1 was repeated except that NUC-6170 manufactured by Nippon Unicar, an ethylene-ethyl acrylate resin, was used as the material for the gasket. The obtained lens was fogged, and had a problem in optical applications.

Comparative Example 2 A gasket was manufactured in the same manner as in Example 2 except that NUC-3461 manufactured by Nippon Unicar Co., Ltd., which is an ethylene-vinyl acetate resin, was used. The obtained lens was fogged, and had a problem in optical applications.

Comparative Example 3 The same procedure as in Example 1 was carried out except that a soft polyvinyl chloride resin was used as a gasket material. The obtained lens was fogged, and had a problem in optical applications.

[0032]

The gasket used for the molding mold of the present invention is made of a thermoplastic polyurethane elastomer.
Injection molding is possible and productivity is good. Therefore, cast polymerization is performed using such a molding mold of the present invention,
The manufacturing method of the plastic lens of the present invention also has improved productivity as compared with the conventional method. Furthermore, since the gasket used in the present invention has monomer resistance to an aromatic ring such as styrene or an acrylic monomer such as methyl methacrylate, it has excellent optical properties without causing clouding or fogging of the lens. Lens is obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-297120 (JP, A) JP-A-60-112408 (JP, A) Shinzo Yamashita, One Note on Rubber and Elastomer Use (1985) December 10) Industrial Research Institute Co., Ltd., pp. 164-165, Akira Hiroe, 1 Introduction to Plastic Properties for Molding Engineers (Eighth Edition, December 20, 1979) Nikkan Kogyo Shimbun, P177 −179 (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 39/22-39/42 B29C 33/38-33/42

Claims (4)

(57) [Claims] 1. A gasket and a molding die, wherein a gas
A mold for forming a plastic lens, wherein the gasket is made of a thermoplastic polyurethane elastomer, wherein the gasket has a structure in contact with a monomer . 2. A method for producing a plastic lens, comprising: injecting a liquid containing a monomer into the mold according to claim 1, and then polymerizing the monomer to obtain a plastic lens. 3. The method according to claim 2, wherein the monomer is an aromatic monomer alone or a monomer mixture containing one or more aromatic monomers. 4. The method according to claim 2, wherein the monomer is a monomer mixture containing one or more monomers selected from the group consisting of acrylates and methacrylates.