JPH0535656B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a method for manufacturing plastic lenses.

"Prior Art and its Problems" Plastic lenses are lighter than inorganic glass lenses, have excellent impact resistance, and are dyeable, so they have been frequently used as lenses for glasses and cameras in recent years.

Conventionally, plastic lenses are usually manufactured by a casting method, but at that time, a glass or metal mold is coated with a mold release agent in advance.
Thereafter, a monomer solution is injected, the monomer is polymerized and cured, the lens is released from the mold, and after cleaning, a hard coat film and an antireflection film are provided.

When coating a plastic lens with a hard coat liquid, the wettability changes depending on the material, making it difficult to form a hard coat film with excellent adhesion. In order to improve adhesion, the surface of plastic lenses is subjected to pretreatment such as activated gas treatment or chemical treatment. However, performing such processing is complicated.

It is also known to form an antireflection film by vacuum deposition of an inorganic compound. Although the vacuum evaporation method can form a dense, hard thin film, it lacks flexibility, and if there is a difference in expansion coefficient with the base material, cracks may occur due to temperature changes. In addition, since plastic is water-absorbing, it cannot be heated sufficiently during vacuum deposition, resulting in an unstable refractive index and variations in the reflected color of the anti-reflection coating.
It takes more than one hour to raise the degree of vacuum to about 10 ^-5 Torr, which has the drawback of lacking productivity and economy.

Additionally, many plastic cleansers require a temperature of 120°C.
At higher temperatures, materials that require heat treatment at high temperatures cannot be used for vapor deposition because they yellow or deform. For example, MgF ₂ has traditionally been used as a component of low refractive index films, but this cannot be applied to plastics because it must be heated to about 200°C.

``Object of the Invention'' The present invention provides a method for manufacturing a plastic lens that can efficiently form an antireflection film and a hard coat film with good adhesion without causing cracks, yellowing, deformation, etc. on the lens. The purpose is to

"Structure of the Invention" The method for manufacturing a plastic lens according to the present invention involves first treating the surfaces of two molds to be used with a mold release agent, then forming an antireflection film thereon by vacuum evaporation, and then , after coating with an organic hard coat liquid and curing it, a monomer liquid is injected into the space formed by the mold and the ring gasket, and the monomer is polymerized.

In the present invention, the mold may be made of glass or metal, and the gasket may be made of any polymer such as polyvinyl chloride, polyvinyl acetate, polyethylene, or silicone rubber. be able to.

To carry out the method of the invention, as described above,
First, the surfaces to be used of two glass or metal molds are treated with a mold release agent. Examples of mold release agents that can be used in the method of the present invention include various silicone mold release agents, fluoroalkylalkoxysilanes, mineral oils, fatty acids, alkyl phosphates, and fatty acid esters. Such a mold release agent is applied by a dip coating method, a spin coating method, or the like, and heat treatment is performed as necessary depending on the type of mold release agent used to harden it. Among mold release agents, fluorine-based silicon coating liquid (manufactured by Shin-Etsu Chemical Co., Ltd., KP-
801) is preferred, and after applying this liquid by dip coating or spin coating, it is heated and cured.

In the method of the present invention, an antireflection film is formed by vacuum evaporation on the use surface of a mold that has been treated with a mold release agent as described above. There are no particular restrictions on the inorganic compounds that can be used to form the antireflection film, and various oxides, halides, and sulfides, such as MgF ₂ , SiO ₂ , and Na ₃ as low refractive index substances, can be used.
(AlF ₄ ), etc., as medium to high refractive index materials.
_{Al2O3 , CeF3} , mixture of MgO and _{Al2O3 , ThO2} ,
Nd ₂ O ₃ , ZrO ₂ , CeO ₂ , TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ ,
Examples include Y ₂ O ₃ , Yb ₂ O ₃ and ZnS.

Although the antireflection film may be a single layer, it is preferably formed by laminating a plurality of layers having different refractive indexes. The film thickness is selected from any combination of film thicknesses depending on the combination of refractive indexes, but when forming an antireflection film consisting of three layers, the optical film thickness is set to 1/4 and 1/4 of the design reference wavelength (λ). /2 and 1/4 or 1/4, 1/4 and 1/4 are preferable.

In the present invention, the anti-reflection film is formed by applying a vacuum deposition method known per se, but since it is deposited on the surface of a mold made of glass or metal, unlike when depositing on a plastic substrate, it is heated. There are no restrictions on conditions such as temperature, and conditions suitable for the substance to be deposited can be adopted.

After the antireflection film is formed on the use surfaces of the two molds as described above, an organic hard coat liquid is coated and cured to form a hard coat film.

The hard coat liquid is not particularly limited and may be any of various known hard coat liquids. For example, a liquid containing at least one of colloidal silica, colloidal antimony oxide, and colloidal titanium oxide as a refractive index adjusting component, and a silane coupling agent and a curing agent as a film forming component, dispersed in a solvent together with other additives. can be used.

Colloidal silica, colloidal antimony oxide, and colloidal titanium oxide are commercially available colloidal solutions in which ultrafine particles of silicic anhydride, antimony pentoxide, or titanium dioxide are dispersed in water or an alcohol-based dispersion medium. The amount of colloidal silica, colloidal antimony oxide, and/or colloidal titanium oxide to be used is appropriately determined depending on the refractive index to be adjusted, but is generally 10 to 80% by weight, preferably 10 to 80% by weight in the hard coat liquid. ~50% by weight.

Any known silane coupling agent can be used, for example, the general formula R ¹ _n R ² _o SiX _4-(n+o) , [wherein R ¹ is an alkyl group, an alkenyl group, a phenyl group] represents a group or halogen;
R ² is an epoxy group, a glycidoxy group, an amino group,
An amide group, a mercapto group, a methacryloyloxy group, a cyano group, or an organic group having a nuclear-substituted aromatic ring; each represents a number from 0 to 2, and m+n≦3], and hydrolysates or partial condensates thereof can be used. Specific examples of these compounds include tetrafunctional compounds such as tetramethoxysilane, methoxysilane from methyl, methyltriethoxysilane, γ
-chloropropyltrimethoxysilane, vinyltrimethoxysilane, γmethacryloyloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane,
γ-Mercaptopropyltrimethoxysilane, γ
-aminopropyltrimethoxysilane, N-β-
(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-cyanopropyltrimethoxysilane,
γ-morpholinopropyltrimethoxysilane, N
- Trifunctional silanes such as phenylaminopropyltrimethoxysilane, and bifunctional silanes in which part of the trifunctional silane is substituted with an alkyl group, phenyl group, vinyl group, etc., such as dimethyldimethoxysilane, phenylmethyldimethoxysilane. Examples include silane, vinylmethyldimethoxysilane, γ-chloropropylmethyldimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. Further, hydrolysates, partial condensates, etc. of these compounds can also be used. The above film-forming components are used in the hard coat liquid in an amount of 1 to 40% by weight, preferably 3 to 20% by weight.

As a curing agent, organic amines such as triethylamine and n-butylamine, amino acids such as glycine, metal acetylacetonates such as aluminum acetylacetonate, chromium acetylacetonate, titania acetylacetonate, and cobalt acetylacetonate, sodium acetate, and naphthene. Organic metal salts such as zinc acid, cobalt naphthenate, zinc octylate, tin octylate, tin chloride,
Examples include Lewis acids such as aluminum chloride, ferric chloride, titanium chloride, zinc chloride, and antimony chloride. Among these, aluminum acetylacetonate is particularly preferred.

Taking coating workability into consideration, it is preferable to dissolve the various components described above in an appropriate solvent to form a hard coat liquid. As a solvent, alcohol,
Ketones, cellosolves, formamides, water,
Various Freon solvents can be used.
Generally, it is preferable to use these solvents as a solution containing 1 to 20% by weight of solids, but the solvent is not limited to this range and can be appropriately selected depending on the situation.

In addition, a surfactant,
UV absorbers, antioxidants, thixotropic agents,
Pigments, dyes, antistatic agents, conductive particles, etc. can be added.

A hard coat liquid containing the various components described above is applied to the use surfaces of two molds by a known method and cured to form a hard coat film. Application can be performed by, for example, flow coating, dip coating, spin coating, roll coating, spray coating, or the like. Drying and curing are appropriately selected depending on the components used, but are preferably carried out by heating at 80 to 300°C for 30 minutes to 3 hours.

Further, in order to promote the crosslinking reaction and polymerization reaction of the reactive groups in the components used, curing can also be carried out by irradiation with infrared rays, ultraviolet rays, γ rays, or electron beams.

The film thickness can be adjusted by using a solvent or a coating method, and is usually 2 to 10 μm, preferably 2 to 5 μm.

After forming a hard coat film on the use surfaces of the two molds in this way, a monomer liquid, which is the raw material for the plastic lens, is injected into the space formed by the two molds and the annular gasket.
Polymerization and curing are performed by a method known per se.

Plastics for lenses include, for example, acrylic resins, polycarbonates, diethylene glycol bisallyl carbonate polymers, di(meth)acrylate polymers of (halogenated) bisphenol A and their copolymers, urethane-modified (halogenated) bisphenol A ( Examples include meth)acrylate polymers and copolymers thereof, polyurethane resins, such as urethane resins composed of diisocyanates and mercaptoalkyl esters of polyols, but there are no particular limitations.

FIG. 1 shows the state of the mold release agent when producing a plastic lens by the method of the present invention. As shown in FIG. 1, a release agent layer 2, an antireflection film 3, and a hard coat film 4 are provided on the use surfaces of two molds 1, and the molds 1 having these films and a gasket are connected to each other. A plastic lens 6 is cast into the space formed by 5 and 5.

The plastic lens taken out from the mold after monomer polymerization and curing by the method of the present invention is a product lens that already has an antireflection film and a hard coat film, and can be dyed if necessary.

"Examples of the Invention" Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, in the examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 (1) Preparation of hard coat liquid with refractive index n=1.60 20 parts of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 60 parts of γ-glycidoxypropyltrimethoxysilane, and γ-glycid Xypropylmethyldiethoxysilane 20
1 part was hydrolyzed with 25 parts of 0.1N hydrochloric acid and stirred overnight. Next, 250 parts of methanol-dispersed antimony oxide sol (manufactured by Nissan Chemical Co., Ltd.), 0.1 part of Zonyl FSN (manufactured by DuPont) as a surfactant, and aluminum acetylacetonate as a hardening agent.
0.5 part and isopropyl alcohol as solvent
A hard coat solution was prepared by mixing 300 parts.
This liquid is hereinafter referred to as hard coat liquid X.

When this hard coat liquid was heated at 150°C for 1 hour, a film with a refractive index of 1.60 was produced.

(2) Manufacturing of plastic lenses Fluorine-based silicone coating liquid (manufactured by Shin-Etsu Chemical Co., Ltd., KP-801) is applied to the two surfaces of the glass mold mold.
was applied using the dip coating method and coated at 120°C.
Cured by heating for hours. Place the glass mold with this mold release agent layer into a vacuum deposition machine, and first
SiO ₂ was vacuum deposited to an optical thickness of λ/4 (λ = 510 nm) to form a layer with a refractive index n = 1.45, and then Ta ₂ O ₅ was deposited to an optical thickness of λ/4 (λ = 510 nm). Vacuum evaporated to an optical thickness and refractive index n=
2.00 layer, and further Yb ₂ O ₃ at λ/4
A layer with a refractive index n=1.80 was formed by vacuum evaporation to an optical thickness of (λ=510 nm).

Next, hard coat liquid X was coated to a thickness of about 2 μm, and heat treated at 150° C. for 1 hour.

In this way, m-xylylene diisocyanate and pentaerythritate tetrakis (3-mercaptopropionate) are placed in a space surrounded by two glass molds provided with a release agent layer, an antireflection film, and a hard coat film, and an annular gasket. 1:
A monomer mixture containing a weight ratio of 1.3 and 1000 ppm of dibutyltin dilaurate as an initiator was injected and heated at 30°C for 8 hours and at 40°C for 5 hours.
A plastic lens was produced by polymerizing at 120°C for 4 hours.

The resulting lens molded product has a total light transmittance of 98.5%.
It was a plastic lens with anti-reflection.

Example 2 (1) Preparation of hard coat liquid with refractive index n=1.50 50 parts of γ-glycidoxypropyltrimethoxysilane and 50 parts of γ-glycidoxypropylmethyldiethoxysilane were hydrated with 25 parts of 0.1N hydrochloric acid. Disassemble and stir overnight. Next, 250 parts of isopropyl alcohol-dispersed silica sol (manufactured by Catalyst Kasei Co., Ltd., OSCAL1432), 0.1 part of Zonyl FSN as a surfactant, 0.5 part of aluminum acetylacetonate as a hardening agent, and 300 parts of isopropyl alcohol as a solvent were mixed to harden the mixture. A coating solution was prepared. This liquid is hereinafter referred to as hard coat liquid Y.

This hard coat liquid produced a film with a refractive index of 1.50 when heated at 150°C for 1 hour.

(2) Manufacturing of plastic lenses Fluorine-based silicone coating liquid (manufactured by Shin-Etsu Chemical Co., Ltd., KP-801) is applied to the two surfaces of the glass mold.
was applied using the dip coating method and coated at 120°C.
Cured by heating for hours. Place the glass mold with this mold release agent layer into a vacuum evaporator, and first
MgF ₂ was vacuum deposited to an optical thickness of λ/4 (λ = 510 nm) to form a layer with a refractive index n = 1.38, and then TiO ₂ was deposited to an optical thickness of λ/2. A layer with a refractive index n=2.08 was formed by vacuum evaporation, and a layer with a refractive index n=1.65 was further formed by vacuum evaporating Al ₂ O ₃ to an optical thickness of λ/4.

Next, hard coat liquid Y was coated to a thickness of about 2 μm, and heat treated at 150° C. for 1 hour.

Diethylene glycol bisallyl carbonate monomer was injected into the space surrounded by the two hard-coated glass molds and the annular gasket as described above, and the mixture was heated at 40°C for 8 hours and then heated at 50°C.
Polymerization was carried out for 2 hours at 70℃, 2 hours at 80℃, and 3 hours at 80℃ to produce a plastic lens.

The resulting lens molded product has a total light transmittance of 98.5%.
It was a plastic lens with anti-reflection.

"Effects of the Invention" According to the method of the present invention, the antireflection film and hard coat film to be provided on the lens are deposited on the use surface of the mold, so the heat treatment conditions for forming these films are limited. First, compared to conventional methods, even if heat treatment is performed at a higher temperature, the plastic lens does not undergo cracking, deformation, or yellowing, and moreover, the heat treatment time can be shortened.

Furthermore, in the conventional method of applying a hard coat liquid to a plastic lens, the wetting characteristics vary depending on the material, but according to the method of the present invention, the wetting characteristics of the hard coat liquid are good. Furthermore, in the method of the present invention, a mold type 2 having a hard coat film is used.
Since the lens is molded by injecting the monomer liquid into the space formed by the lens film and the gasket, the adhesion between the hard coat film and the lens is improved compared to the conventional method of applying hard coat liquid to the lens molded body. Are better.

The product obtained by the method of the present invention is hard-coated, so it is easy to handle, and it is also resistant to heat, so it can be dyed.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a plastic lens manufactured by the method of the present invention before being released from the mold. Explanation of symbols 1...mold type, 2...mold release agent layer,
3...Antireflection film, 4...Hard coat film, 5...Gasket, 6...Plastic lens.

Claims (1)

[Claims] 1. First, the surfaces of the two molds to be used are treated with a mold release agent, and then an anti-reflection film is formed thereon using a vacuum evaporation method. Next, an organic hard coat liquid is coated, and after curing, A method for producing a plastic lens, comprising injecting a monomer liquid into a space formed by the mold and an annular gasket, and polymerizing the monomer.