JPH05255650A - Adhesive tape for producing plastic lens - Google Patents

Abstract

PURPOSE:To obtain an adhesive tape capable of sealing the sides of two molds in producing a plastic lens by a cast molding method. CONSTITUTION:The objective adhesive tape for producing a plastic lens is obtained by forming a pressure-sensitive adhesive composition containing an alkyl (meth)acrylate unit having 1-14C alkyl group as a chief component and <=30% fraction soluble in toluene (20 deg.C). This tape neither elutes the adhesive component into a lens raw material nor causes the adhesive component to remain on the mold surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic lens manufacturing adhesive used for sealing the side surfaces of two molds positioned at a predetermined interval when molding a plastic lens by a casting polymerization method. The present invention relates to a tape and a method for manufacturing a plastic lens using the tape.

[0002]

2. Description of the Related Art Among plastic lenses, a casting method is generally used for manufacturing lenses such as eyeglass lenses which are required to have high performance.

The cast molding method is a method of injecting a liquid lens raw material into a mold having a lens shape, polymerizing and hardening by heating or the like, and then removing the mold to obtain a lens.

The mold used in this cast molding method is generally one in which the side surfaces of two molds are fixed and sealed with a gasket, but the mold has flexibility and flexibility to follow the shrinkage of the cured product during polymerization. There are many requirements such as heat resistance for heating during curing, so there are many restrictions on the materials used, and even though it is necessary to prepare various types of gaskets according to the size of the lens, it is disposable Therefore, there is a disadvantage that the molding processing cost becomes high.

In order to solve the problems caused by using these gaskets, a method has been proposed in which the side surfaces of the two molds are replaced with gaskets and fixed and sealed with an adhesive tape (for example, JP-A-56-56). No. 135030).

[0006]

However, in the above proposed method, since the adhesive layer surface of the adhesive tape to be used and the liquid lens raw material are in direct contact with each other, the components in the adhesive are It may be dissolved in the lens raw material to affect the cured state of the raw material, or turbidity may occur in the lens after curing.

As a means for solving such problems of curability and turbidity, it has been proposed to use an adhesive tape provided with an adhesive layer made of a specific adhesive composition in a casting method (for example, Japanese Patent Laid-Open Publication No. Sho. 61-148282).

Also in this proposed method, since the adhesive composition contains rubber and the adhesion-imparting resin as the main components, the elution resistance to the lens raw material was insufficient. This is because the main component is essentially high in solubility in an organic solvent such as toluene, and it is technically difficult to form a sufficiently crosslinked structure even if it is crosslinked for the purpose of decreasing the solubility. There is. In addition, this adhesive has insufficient heat resistance, and there are many restrictions on the temperature and time during production, and adhesive residue is left on the mold surface, requiring cleaning work.

[0009]

[Means for Solving the Problems] The inventors of the present invention have made diligent studies to solve the problems, and as a result, toluene (2
The inventors have found that the above problems can be solved by using a pressure-sensitive adhesive layer designed so that the soluble fraction with respect to 0 ° C.) becomes a predetermined value, and have completed the present invention. is there.

That is, the present invention is an adhesive tape for producing a plastic lens, which comprises a support such as a plastic film or sheet and a pressure-sensitive adhesive layer, the adhesive layer being coated with toluene (20 ° C.). Soluble fraction is 30%
The present invention provides an adhesive tape for producing a plastic lens, characterized in that the pressure-sensitive adhesive layer is mainly composed of a (meth) acrylic acid alkyl ester unit having an alkyl group having 1 to 14 carbon atoms. It is intended to provide an adhesive tape for producing a plastic lens, which is characterized by comprising an acrylic polymer as a component.

Further, according to the present invention, the adhesive tape for producing a plastic lens is adhered and sealed to the side surfaces of two molds which are substantially positioned at a predetermined interval, and is enclosed by the mold and the tape. The present invention also provides a method for producing a plastic lens, which is characterized by injecting a lens raw material into the formed mold and polymerizing the same.

[0012]

The adhesive tape for producing a plastic lens of the present invention is adhered to the side surface of a mold and hermetically sealed, and a mold formed by being surrounded by the mold and the tape is formed, whereby the lens raw material is removed from the mold. It prevents leakage and prevents elution of the adhesive component into the lens raw material to prevent obstruction of the curability of the lens raw material and turbidity of the lens. No adhesive component remains.

[0013]

The adhesive tape for producing a plastic lens of the present invention comprises a support such as a plastic film or sheet and a pressure sensitive adhesive layer. The support is made of two molds. Film having a thickness of about 10 to 300 μm, which is generally known, as long as it has physical strength, chemical resistance not affected by the lens raw material, heat resistance to heat when polymerizing the lens raw material, and the like. Sheets are used.

Examples of preferable film or sheet materials include mono- or biaxially stretched polyester films or sheets, polyolefin films or sheets, and the like, for example, metal foil, woven cloth, non-woven cloth, etc. Good.

On the surface of the support, such as a plastic film or sheet, on which the adhesive layer is formed, generally known undercoating agent coating treatment, corona discharge treatment, plasma treatment are carried out for the purpose of improving the adhesiveness between the support and the adhesive layer. Physical or chemical treatment such as electric discharge treatment can be performed.

The pressure-sensitive adhesive layer formed on the surface of a support such as a plastic film or sheet is made of rubber and / or synthetic resin as long as the soluble fraction in toluene (20 ° C.) is 30% or less. The pressure-sensitive adhesive composition may be a main component.

In the present specification, "toluene (20
℃) "soluble fraction" means that 1g of pressure sensitive adhesive was immersed in 100g of toluene (20 ° C) for 168 hours, and then the toluene solution was filtered with a 250 mesh nylon filter cloth, and filtration was impossible. It means that the soluble content was calculated from the weight of the pressure-sensitive adhesive after drying by the percentage method.

The pressure-sensitive adhesive used in the present invention is not limited as long as it has a soluble fraction of 30% or less in toluene (20 ° C.) as described above, but it does not have a high molecular weight and a high degree of cross-linking structure. A pressure-sensitive adhesive composition containing an acrylic polymer as a main component is preferable because it is possible and can maintain pressure-sensitive adhesiveness.

That is, the pressure-sensitive adhesive composition containing an acrylic polymer having a high molecular weight and a high degree of cross-linking structure as a main component is an adhesive composition even when it is brought into contact with a liquid monomer which is a lens raw material. Not only the ingredients are not compatible with the lens raw material,
It is preferable in that it maintains sufficient adhesiveness to adhere to the mold and hold the mold. Moreover, since the pressure-sensitive adhesive composition containing an acrylic polymer as a main component has completed the formation of a high-molecular weight substance and a high degree of cross-linking structure, its cohesive force is less likely to decrease even by heating during polymerization, and the mold Adhesiveness to, that is, mold holding performance is sufficient, and
Even if the mold is disassembled when the lens is taken out, no adhesive component remains on the mold surface.

The pressure-sensitive adhesive composition containing an acrylic polymer as a main component, which is preferably used in the present invention, is a (meth) acrylic acid alkyl ester unit having an alkyl group having 1 to 14 carbon atoms from the viewpoint of adhesive properties. It is preferable that the main component is an acrylic polymer containing as a main component. In particular, an acrylic polymer containing 50% by weight or more of a (meth) acrylic acid alkyl ester unit having an alkyl group with 1 to 14 carbon atoms is preferable. Those containing the main component are preferable. Can be used (meta)
Examples of the acrylic acid alkyl ester include monomers such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, butyl methacrylate, hexyl methacrylate, and lauryl methacrylate. Homopolymers or copolymers of one or more of these are used. However, it may be a copolymer of the above-mentioned (meth) acrylic acid alkyl ester and a monoethylenically unsaturated monomer.

The monoethylenically unsaturated monomer copolymerizable with the above-mentioned monomer is copolymerized with the above-mentioned monomer to introduce a functional group or a polar group, thereby improving adhesion or a copolymer. It is not particularly limited as long as it can contribute to the improvement of cohesive force and heat resistance by controlling the glass transition temperature of, for example, a polymerizable monomer having a carboxyl group such as (meth) acrylic acid, maleic acid, and itaconic acid. Body, acrylic acid-2-
Polymerizable monomers having a hydroxyl group such as hydroxyethyl ester, acrylic acid-2-hydroxypropyl ester and 2-hydroxyvinyl ether, N.I. Polymerizable monomer having amino group such as N-dimethylaminoethyl acrylate and N-tert-butyl-aminoaminoethyl acrylate, polymerizable monomer having glycidyl group such as glycidyl acrylate and glycidyl methacrylate, acrylamide, meta Polymerizable monomers having an amide group such as acrylamide, acrylonitrile, methacrylonitrile, vinyl acetate, N-vinylcaprolactam, styrene, and the like or derivatives thereof can be mentioned, and one or more of these can be used.

The (meth) acrylic acid alkyl ester and the ethylenically unsaturated monomer copolymerizable therewith can be produced by a generally known polymerization method such as bulk polymerization, solution polymerization, dispersion polymerization and emulsion polymerization. Can be copolymerized using benzoyl peroxide, lauroyl peroxide,
A thermal initiator such as azobisisobutyronitrile, a photoinitiator such as benzoin, benzoin methyl ether, and benzophenone, and ultraviolet irradiation, electron beam irradiation, or any other generally known means can be employed.

The pressure-sensitive adhesive composition used in the present invention is composed of an acrylic homopolymer or copolymer as described above, and such a polymer is preferably subjected to a crosslinking treatment. The cross-linking treatment may be carried out by using a cross-linking monomer such as a polyfunctional vinyl compound known as an internal cross-linking agent during the polymerization step, or adding a generally known cross-linking agent such as an isocyanate compound or an epoxy compound after the polymerization step. Can be processed.

The pressure-sensitive adhesive composition used in the present invention contains an adhesion-imparting resin, an antioxidant, a colorant, and
Although generally known additives such as fillers can be added in appropriate amounts, the amount of these additives is toluene (20 ° C).
Soluble content in the above range is limited to the above range within a range satisfying the pressure-sensitive adhesive composition.

The adhesive layer is formed on a support such as a plastic film or sheet by dispersing or dissolving the pressure-sensitive adhesive composition in water or a solvent, coating the surface of the support and drying, or by using an acrylic resin. It can be carried out by coating the monomer composition on a support and polymerizing it on the support.
The thickness of the adhesive layer is preferably about 15 to 200 μm.

A method of producing a plastic lens using the adhesive tape for producing a plastic lens of the present invention will be described. Two glass molds are held by a holder and positioned at a predetermined interval to fix the state. Then, the tape is attached around the side faces of the two fixed molds to form a mold, and a lens material is injected into the mold and heated to cure the material. The lens can be obtained by peeling the tape from the mold.

As the lens raw material, generally used diethylene glycol bisallyl carbonate,
Allyl carbonates such as diallyl carbonate, diethylene glycol bis methacryl carbonate and ethylene glycol bis allyl carbonate, unsaturated alcohol esters such as diallyl phthalate, triallyl isocyanurate and diallyl benzoate, unsaturated such as methyl methacrylate, glycol dimethacrylate and glycidyl methacrylate Examples thereof include acid esters, monomers such as styrene and derivatives thereof, or a mixture thereof, and a prepolymer which is a partial polymer.

[0028]

When a lens is produced by the cast polymerization method using the adhesive tape for producing a plastic lens of the present invention, there is no obstruction of the curing of the raw material due to the elution of the adhesive component into the lens raw material and turbidity of the lens. Even if the tape is peeled off from the mold surface, there is no residue and no cleaning work is required.

[0029]

EXAMPLES Next, the present invention will be described in more detail with reference to examples.
The term "parts" means "parts by weight". Example 1 A composition prepared by adding 0.5 part of benzoin methyl ether as a photopolymerization initiator to a monomer mixture consisting of 90 parts of n-butyl acrylate and 10 parts of acrylic acid was pre-irradiated with ultraviolet rays to prepare a composition. The viscosity was increased to such a level that the support could be applied, and 0.3 part of trimethylolpropane triacrylate as an internal cross-linking agent was added and mixed thereto. This was applied to a biaxially stretched polyethylene terephthalate film having a thickness of 38 μm by setting the thickness to 40 μm, and further irradiated with ultraviolet rays to cause a polymerization reaction to obtain an adhesive tape for producing a plastic lens. The soluble fraction of the adhesive layer of this tape was 15%.

Next, two glass molds forming the optical surface of the plastic lens are held and fixed at an interval corresponding to the thickness of the lens, and the tape is attached to the side surface of the mold so as to straddle the mold with 1.2. A mold was formed by pasting around.

A liquid lens raw material consisting of 100 parts of diethylene glycol bisallyl carbonate and 0.1 part of diisopropyl peroxydicarbonate was poured into the formed mold and gradually heated from 40 ° C. to 110 ° C. over 35 hours. The raw material was polymerized and cured, and after cooling to room temperature, the tape was peeled off and the mold was removed from the cured product to obtain a lens.

The obtained lens was colorless and transparent without turbidity due to elution of the adhesive component, and no adhesive component remained on the side surface of the mold which was the tape peeling surface.

Example 2 In a reactor equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux cooling tube, a monomer mixture consisting of 95 parts of 2-ethylhexyl acrylate and 5 parts of acrylic acid, and a thermal polymerization initiator. Was charged with 0.4 part of azobisisobutyronitrile and 100 parts of ethyl acetate, the inside of the reactor was filled with a nitrogen atmosphere, and the mixture was heated to 60 ° C. to carry out a polymerization reaction to obtain a copolymer solution.
0.2 part of a tetrafunctional epoxy crosslinking agent was added and mixed with 100 parts of the solid content of this copolymer solution. This is thickness 3
8 μm biaxially stretched polyethylene terephthalate film was applied so that the thickness after drying would be 40 μm,
After drying at 120 ° C for 3 minutes, it was stored at 50 ° C for 3 days to obtain an adhesive tape. The soluble fraction of the adhesive component was 25%.

Using this tape, a lens was manufactured in the same manner as in Example 1. As a result, the lens was colorless and transparent without turbidity, and no adhesive component remained on the side surface of the mold.

Example 3 As a monomer mixture, 2-ethylhexyl acrylate 9 was used.
Using 5 parts and 5 parts of acrylic acid and 0.4 part of polyethylene glycol dimethacrylate as an internal cross-linking agent, an adhesive tape was obtained by the same procedure as in Example 1 below. The soluble fraction of the adhesive component was 12%.

When a lens was produced in the same manner as in Example 1 using this tape, it was colorless and transparent without turbidity, and no adhesive component remained on the side surface of the mold.

Example 4 88 parts of isooctyl acrylate as a monomer mixture,
An adhesive tape was obtained by the same procedure as in Example 1, except that 12 parts of acrylic acid and 0.2 part of trimethylolpropane triacrylate as an internal cross-linking agent were added to the composition. The soluble fraction of the adhesive component was 20%.

Using this tape, a lens was manufactured in the same manner as in Example 1. As a result, the lens was colorless and transparent without turbidity, and no adhesive component remained on the side surface of the mold.

Comparative Example 1 An adhesive tape was obtained in the same manner as in Example 1 except that the amount of the internal cross-linking agent (trimethylolpropane triacrylate) added was 0.04 part. The soluble fraction of the adhesive component was 45%. When a lens was produced in the same manner as in Example 1 using this tape, turbidity which is considered to be caused by elution of the adhesive component was observed in the lens, and residual adhesive component was observed on the side surface of the mold.

Comparative Example 2 An adhesive tape was obtained in the same manner as in Example 2 except that 2 parts of a trifunctional isocyanate crosslinking agent was added as a crosslinking agent. The soluble fraction of the adhesive component was 62%. When a lens was produced in the same manner as in Example 1 using this tape, turbidity which is considered to be caused by elution of the adhesive component was observed in the lens, and residual adhesive component was observed on the side surface of the mold.

Comparative Example 3 100 parts of natural rubber, 60 parts of a terpene resin, 30 parts of an aliphatic petroleum resin synthesized from a fraction having 5 carbon atoms and 7 parts of toluene.
Biaxially stretched polyethylene terephthalate film having a thickness of 38 μm prepared by adding 60 parts of a thiuram compound as a vulcanization accelerator to a pressure-sensitive adhesive composition by uniformly dissolving and mixing it. The thickness after drying is 40 μm
And then dry at 120 ℃ for 2 minutes, 50 ℃
It was stored for 3 days to obtain an adhesive tape. The soluble fraction of the adhesive component was 60%. Example 1 using this tape
When a lens was manufactured in the same manner as in, the turbidity that was considered to be caused by the elution of the adhesive component was observed in the lens, and the adhesive component remained on the side surface of the mold.

Claims (2)

[Claims] 1. An adhesive tape for producing a plastic lens, which comprises a support such as a plastic film or sheet and a pressure-sensitive adhesive layer, wherein the adhesive layer has a soluble fraction in toluene (20 ° C.). Is 30% or less, an adhesive tape for producing a plastic lens. 2. The pressure-sensitive adhesive layer is composed of an acrylic polymer whose main component is a (meth) acrylic acid alkyl ester unit having an alkyl group having 1 to 14 carbon atoms. Adhesive tape for manufacturing plastic lenses.