JP6725037B1 - Pressure-sensitive adhesive layer, pressure-sensitive adhesive sheet, laminate, and method for manufacturing laminate - Google Patents

Abstract

Provided are a pressure-sensitive adhesive layer capable of forming a pressure-sensitive adhesive sheet having low moisture permeability and excellent durability, a pressure-sensitive adhesive sheet including the pressure-sensitive adhesive layer, a laminate, and a method for producing the laminate. .. SOLUTION: The pressure-sensitive adhesive layer of the present invention contains a pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction-type initiator, and has an active energy ray accumulated light amount of 3000 mJ/cm2. The following physical properties (1) and (2) are satisfied when post-curing is performed by irradiating the above materials. Physical properties (1): In a tensile test measurement at a tensile speed of 10 mm/min, the breaking elongation is 1200% or more, and the stress at a strain of 1000% is 0.40 N/mm 2 or more. Physical property (2): Moisture permeability at a thickness of 100 μm is 50 g/m2·24 hr or less. [Selection diagram] None

Description

The present invention relates to a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, a laminate, and a method for producing a laminate.

2. Description of the Related Art Conventionally, in image display devices such as liquid crystal display devices, an adhesive sheet has been used to bond optical members. Since such an image display device is liable to deteriorate in quality due to the influence of moisture or the like, it is required to provide a pressure-sensitive adhesive sheet with a property of not allowing moisture to permeate, that is, a low moisture-permeable pressure-sensitive adhesive sheet. ..

For example, Patent Documents 1 and 2 disclose a technique of obtaining a low moisture-permeable pressure-sensitive adhesive sheet using a rubber-based pressure-sensitive adhesive composition containing polyisobutylene and a hydrogen abstraction type photopolymerization initiator. Further, Patent Document 3 discloses a technique for obtaining a low moisture-permeable pressure-sensitive adhesive sheet using a rubber-based pressure-sensitive adhesive composition containing an isobutylene-based polymer having a polydispersity (weight average molecular weight/number average molecular weight) of 4 or less. ing.

JP, 2017-119847, A JP, 2017-203835, A JP, 2008-39863, A

However, a pressure-sensitive adhesive sheet obtained using a conventional rubber-based pressure-sensitive adhesive composition has low moisture permeability, but is not sufficiently durable, and bubbles are generated on the adhesive surface after bonding, or peeling occurs. There was a problem that occurred. From such a viewpoint, the pressure-sensitive adhesive sheet used in an image display device or the like has been required to have excellent durability in addition to low moisture permeability.

The present invention has been made in view of the above, and has a low moisture permeability, and a pressure-sensitive adhesive layer capable of forming a pressure-sensitive adhesive sheet having excellent durability, and a pressure-sensitive adhesive sheet including the pressure-sensitive adhesive layer, a laminate An object of the present invention is to provide a method for manufacturing a body and a laminated body.

The present inventors have conducted extensive studies to achieve the above object, and as a result, use a pressure-sensitive adhesive composition containing a polyolefin and a (meth)acrylic monomer, and after post-curing the pressure-sensitive adhesive composition. The inventors have found that the above object can be achieved by setting the mechanical properties within a specific range, and have completed the present invention.

That is, the present invention includes the subject matter described in the following sections, for example.
Item 1
Including a pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction-type initiator,
The following physical properties (1) and (2) when irradiated with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² and post-cured
Physical properties (1): In a tensile test measurement at a tensile speed of 10 mm/min, a breaking elongation is 1200% or more, and a stress at a strain of 1000% is 0.40 N/mm ² or more,
Physical properties (2): Water vapor permeability at a thickness of 100 μm is 50 g/m ² ·24 hr or less,
Adhesive layer that fills.
Item 2
Item 2. The pressure-sensitive adhesive layer according to Item 1, wherein the polyolefin is an ethylene-propylene copolymer.
Item 3
Item 3. The pressure-sensitive adhesive layer according to Item 1 or 2, wherein the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is 1 to 25 parts by mass with respect to 100 parts by mass of the polyolefin.
Item 4
Item 1. The (meth)acrylic monomer is a mixture of a polyfunctional monomer having two or more polymerizable functional groups in the molecule and a monofunctional monomer having only one polymerizable functional group in the molecule. The pressure-sensitive adhesive layer according to any one of 3 above.
Item 5
Item 5. The pressure-sensitive adhesive layer according to any one of Items 1 to 4, which has a relative dielectric constant of 3.0 or less.
Item 6
Item 6. The pressure-sensitive adhesive layer according to any one of items 1 to 5, which has a thickness of 5 to 200 µm.
Item 7
A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer according to any one of items 1 to 6.
Item 8
A laminate comprising the pressure-sensitive adhesive sheet according to item 7 or a cured product thereof.
Item 9
Item 7. The step of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet according to item 7, and the step of post-curing the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays in order. A method for producing a laminated body having.

The pressure-sensitive adhesive layer according to the present invention can form a pressure-sensitive adhesive sheet having low moisture permeability and excellent durability.

It is an example of the embodiment of the adhesive sheet of the present invention, and is a schematic diagram showing the section. It is an example of the embodiment of the layered product of the present invention, and is a schematic diagram showing the section.

Hereinafter, embodiments of the present invention will be described in detail. In this specification, the expressions "containing" and "including" include the concepts of "containing", "including", "consisting essentially of" and "consisting only".

1. Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer of the present invention contains a pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction-type initiator, and has an active energy ray accumulated light amount of 3000 mJ/cm ² . The following physical properties (1) and (2) are satisfied when post-curing is performed by irradiating so that
Physical Properties (1): In a tensile test measurement at a tensile speed of 10 mm/min, the breaking elongation is 1200% or more, and the stress at a strain of 1000% is 0.40 N/mm ² or more.
Physical properties (2): Water vapor permeability at a thickness of 100 μm is 50 g/m ² ·24 hr or less.

(Adhesive composition)
The pressure-sensitive adhesive layer can be formed using a pressure-sensitive adhesive composition, as described below. The pressure-sensitive adhesive composition contains at least a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction initiator.

In the pressure-sensitive adhesive composition, the type of polyolefin is not particularly limited, and, for example, known polyolefins can be widely adopted. When the pressure-sensitive adhesive composition contains polyolefin, the pressure-sensitive adhesive layer can satisfy the physical property (2) and can have low moisture permeability.

Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer and the like. The polyolefin is preferably an ethylene-propylene copolymer from the viewpoint that the obtained pressure-sensitive adhesive layer has low moisture permeability and is easily excellent in durability. In the polyolefin, the polyolefin main chain may contain a monomer unit other than the olefin as long as the effect of the present invention is not impaired.

The number of polyolefins contained in the pressure-sensitive adhesive composition may be only one, or may be two or more different types.

The method for producing the polyolefin is not particularly limited, and for example, the polyolefin can be produced by a known production method. Alternatively, the polyolefin can be obtained from a commercially available product or the like. Examples of commercially available polyolefin products include T7241, EP33, EP35, EP331, EP342, EP251 and EP65 manufactured by JSR.

The type of the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is not particularly limited, and for example, known (meth)acrylic monomers can be widely adopted. In addition, in this specification, "(meth)acryl" means "acryl" or "methacryl", and "(meth)acrylate" means "acrylate" or "methacrylate".

In particular, the (meth)acrylic monomer is preferably a mixture of a polyfunctional monomer having two or more polymerizable functional groups in the molecule and a monofunctional monomer having only one polymerizable functional group in the molecule. In this case, the obtained pressure-sensitive adhesive layer can have excellent durability while maintaining low moisture permeability.

Here, the polymerizable functional group means, for example, a functional group capable of radical polymerization, specifically a polymerizable double bond, and more specifically as a polymerizable double bond ( An example is a (meth)acryloyl group.

In the polyfunctional monomer, the number of polymerizable functional groups in the molecule is not particularly limited, but the number of polymerizable double bonds in one molecule is 2 or more in terms of excellent durability of the obtained adhesive layer. The number may be 5 or less, preferably 2 or more and 3 or less, and particularly preferably 2.

Specific examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, di(meth)acrylic acid 1, 4-butylene glycol, 1,9-nonanediol di(meth)acrylic acid, 1,6-hexanediol diacrylic acid, polybutylene glycol di(meth)acrylic acid, neopentyl glycol di(meth)acrylic acid, di(meth)acrylic acid ) Tetraethylene glycol acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tetra(meth)acrylic (Meth)acrylic acid esters of polyhydric alcohols such as acid pentaerythritol; vinyl methacrylate, dimethylol tricyclodecane diacrylate, and the like.

A commercially available product can be used as the polyfunctional monomer. Examples of commercially available polyfunctional monomers include dimethylol tricyclodecane diacrylate (Kyoeisha Chemical Co., Ltd., light acrylate DCP-A), bisphenol A ethylene oxide modified diacrylate (Toagosei Co., Ltd., Aronix M). -211B) and the like.

The monofunctional monomer has only one polymerizable functional group in the molecule. Specific examples of monofunctional monomers include alkyl (meth)acrylates such as isobornyl (meth)acrylate, isostearyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate; and benzyl. (Meth)acrylate, N-(meth)acryloyloxyethylhexahydrophthalimide, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, (meth)acryloylmorpholine, vinylpyrrolidone And so on. The monofunctional monomer is preferably an alkyl(meth)acrylate, more preferably at least one selected from isobornyl acrylate and isostearyl acrylate, and more preferably isobornyl acrylate. Examples of commercially available monofunctional monomers include IBXA manufactured by Osaka Organic Chemical Industry, ISTA manufactured by Osaka Organic Chemical Industry, and the like.

When the (meth)acrylic monomer is a mixture of the polyfunctional monomer and the monofunctional monomer, the mixing ratio of both is not particularly limited. For example, the content ratio of the polyfunctional monomer may be 1 to 99% by mass, preferably 10 to 90% by mass, and preferably 20 to 80% by mass, based on the total amount of the polyfunctional monomer and the monofunctional monomer. %, more preferably 30 to 70% by mass, particularly preferably 40 to 60% by mass.

When the (meth)acrylic monomer is a mixture of the polyfunctional monomer and the monofunctional monomer, the mixture may contain other monomers as long as the effects of the present invention are not impaired. .. When the mixture contains other monomers, the content thereof may be 10% by mass, preferably 5% by mass or less, more preferably 1% by mass or less, based on the total amount of the mixture. Is particularly preferably 0.1% by mass or less.

The content of the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is not particularly limited as long as low moisture permeability is maintained. For example, the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition may be 1 to 25 parts by mass with respect to 100 parts by mass of the polyolefin. In this case, the obtained pressure-sensitive adhesive layer can easily satisfy both the property (1) and the physical property (2), and as a result, it can have excellent durability while maintaining low moisture permeability. The lower limit of the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is preferably 2 parts by mass, more preferably 3 parts by mass, and more preferably 5 parts by mass with respect to 100 parts by mass of the polyolefin. Is particularly preferable. The upper limit of the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is preferably 20 parts by mass, more preferably 18 parts by mass, and 15 parts by mass with respect to 100 parts by mass of the polyolefin. Is particularly preferable.

The hydrogen abstraction type initiator contained in the pressure-sensitive adhesive composition is not particularly limited, and for example, known hydrogen abstraction type initiators can be widely used. The hydrogen abstraction type photopolymerization initiator, by irradiating with an active energy ray described below, the initiator itself is not cleaved, hydrogen from the acrylic modified polyolefin or a diene polymer having a 1,2-vinyl group described below. It is a polymerization initiator having a property of being capable of drawing out a reaction point in the polymer. Due to the formation of the reaction points, a crosslinking reaction of the polymer is formed.

Examples of the hydrogen abstraction type photopolymerization initiator include methyl benzoylformate; 4-methylbenzophenone, acetophenone, benzophenone, methyl-4-phenylbenzophenone O-benzoylbenzoate, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4, 4'-dimethoxybenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dimethylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra Benzophenone compounds such as (t-butylperoxycarbonyl)benzophenone and 3,3′-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichloro. Thioxanthone compounds such as thioxanthone; 4,4′-bis(dimethylamino)benzophenone, aminobenzophenone compounds such as 4,4′-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9 , 10-phenanthrenequinone, camphorquinone and the like; aromatic ketone compounds such as acetonaphthone and 1-hydroxycyclohexyl phenyl ketone; aromatic aldehydes such as terephthalaldehyde and quinone-based aromatic compounds such as methylanthraquinone. These may be used alone or in combination of two or more. Among these, benzophenone compounds are preferable, and 4-methylbenzophenone is more preferable, from the viewpoint of reactivity.

In the pressure-sensitive adhesive composition, the content ratios of the (meth)acrylic monomer and the hydrogen abstraction initiator are not particularly limited. For example, in the pressure-sensitive adhesive composition, the content of the hydrogen abstraction initiator can be 0.05 to 30 parts by mass, and 0.1 to 25 parts by mass with respect to 100 parts by mass of the (meth)acrylic monomer. It is preferable that the amount is 0.2 to 20 parts by mass.

The pressure-sensitive adhesive composition may contain other components in addition to the polyolefin, the (meth)acrylic monomer and the hydrogen abstraction initiator. For example, the pressure-sensitive adhesive composition can further contain a diene polymer having a 1,2-vinyl group.

The diene polymer having a 1,2-vinyl group is not particularly limited, and known diene polymers can be widely adopted as long as they have a 1,2-vinyl group. Particularly, the diene polymer having a 1,2-vinyl group is preferably a polymer having a non-conjugated diene structure in the molecule. Examples of such a diene polymer include polybutadiene and the like. The diene-based polymer having a 1,2-vinyl group may be a copolymer, for example, a copolymer of acrylonitrile and butadiene, a copolymer of styrene and butadiene, a copolymer of isoprene and butadiene, and isobutylene. Examples thereof include a butadiene copolymer.

The diene-based polymer having a 1,2-vinyl group contained in the pressure-sensitive adhesive composition may be only one type, or may be two or more different types.

The method for producing the 1,2-vinyl group-containing diene polymer is not particularly limited, and for example, a 1,2-vinyl group-containing diene polymer can be obtained by a known production method. Alternatively, the diene polymer having a 1,2-vinyl group can be obtained from a commercial product or the like. Examples of such a diene polymer having a 1,2-vinyl group include, as polybutadiene, RICON130, RICON131, RICON134, RICON142, RICON150, RICON152, RICON153, RICON154, RICON154, RICON156, RICON157, RICON manufactured by TOTAL. P30D etc. can be mentioned.

When the pressure-sensitive adhesive composition contains a diene polymer having a 1,2-vinyl group, the content ratios of the acrylic modified polyolefin, the hydrogen abstraction initiator and the diene polymer having a 1,2-vinyl group are not particularly limited. .. For example, in the pressure-sensitive adhesive composition, the lower limit of the content of the diene-based polymer having a 1,2-vinyl group can be 0.1 parts by mass, and 0.5 parts by mass with respect to 100 parts by mass of the polyolefin. And preferably 1.0 part by mass. In the pressure-sensitive adhesive composition, the upper limit of the content of the diene polymer having a 1,2-vinyl group may be 15 parts by mass, preferably 10 parts by mass, based on 100 parts by mass of the polyolefin. , 8 mass is more preferable.

The pressure-sensitive adhesive composition preferably further contains a tackifier in order to enhance the tackiness and durability of the pressure-sensitive adhesive layer. The type of tackifier is not particularly limited, and for example, known tackifiers used in pressure-sensitive adhesive sheets can be widely used.

Examples of the tackifier include an aromatic tackifier, a tackifier containing a terpene skeleton, a tackifier containing a rosin skeleton, and a petroleum resin tackifier. When the pressure-sensitive adhesive composition contains a tackifier, the type thereof may be only one type, or may be two or more types.

The softening point (softening temperature) of the tackifier is not particularly limited, and is preferably about 90° C. or higher, about 100° C. or higher, and preferably about 200° C. or lower. It is preferably about 180° C. or lower. The softening point of the tackifying resin here is defined as a value measured by the softening point test method (ring and ball method) defined in either JIS K5902 or JIS K2207.

The weight average molecular weight (Mw) of the tackifier is not particularly limited and may be, for example, 50,000 or less, preferably 30,000 or less, more preferably 10,000 or less, and 8000 or less. It is more preferable to be present, and it is particularly preferable to be 5000 or less. The weight average molecular weight (Mw) of the tackifier can be, for example, 500 or more, preferably 1000 or more, and more preferably 2000 or more.

When the pressure-sensitive adhesive composition contains the tackifier, the content thereof is not particularly limited. For example, in the pressure-sensitive adhesive composition, the lower limit of the content of the tackifier may be 1 part by mass, preferably 10 parts by mass, and preferably 20 parts by mass with respect to 100 parts by mass of the polyolefin. Is more preferable. In addition, in the pressure-sensitive adhesive composition, the upper limit of the content of the tackifier can be 80 parts by mass, preferably 70 parts by mass, and preferably 60 parts by mass with respect to 100 parts by mass of polyolefin. More preferable.

The method for preparing the pressure-sensitive adhesive composition is not particularly limited, and it can be prepared by mixing predetermined raw materials in a predetermined content ratio. The mixing method is not particularly limited, and for example, a commercially available mixer can be used.

The pressure-sensitive adhesive composition may contain other components, for example, an antistatic agent, an antioxidant, a preservative and the like, as long as the effects of the present invention are not impaired. When the pressure-sensitive adhesive composition contains other components, the content is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, particularly preferably 1% by mass or less, based on the total mass of the pressure-sensitive adhesive composition. It can be preferably 0.1% by mass or less.

(Method for forming adhesive layer)
The method for forming the pressure-sensitive adhesive layer is not particularly limited, and, for example, known methods can be widely applied. Specifically, the method for forming a pressure-sensitive adhesive layer includes a step of applying the pressure-sensitive adhesive composition on a substrate to form a coating film of the pressure-sensitive adhesive composition, and a drying treatment of the coating film to form a pressure-sensitive adhesive. A step of forming a layer can be provided.

When the pressure-sensitive adhesive composition is applied to the substrate, the pressure-sensitive adhesive composition may contain a solvent in order to improve the coatability. The solvent is not particularly limited, and examples thereof include ester compounds such as methyl acetate and ethyl acetate; ether compounds such as diethyl ether; ketone compounds such as acetone and methyl ethyl ketone; aliphatic hydrocarbons such as hexane and heptane; alicyclic rings such as cyclohexane. Formula hydrocarbons; aromatic hydrocarbons such as benzene, toluene and xylene; chlorinated hydrocarbons such as chloroform and 1,2-dichloroethane; alcohols such as methanol, ethanol, isopropyl alcohol and t-butanol. The solvent can be used alone or as a mixture of two or more kinds.

When the pressure-sensitive adhesive composition contains a solvent, it is preferable to use the solvent in consideration of coatability so that the solid content concentration of the pressure-sensitive adhesive composition is in the range of 10 to 60% by mass. It is more preferable to use a solvent so that it is in the range of %. In the manufacturing process of the pressure-sensitive adhesive layer, all or most of the solvent contained in the pressure-sensitive adhesive layer is volatilized.

The method of applying the pressure-sensitive adhesive composition onto the substrate is not particularly limited, and, for example, known coating methods can be widely adopted. For example, the adhesive composition is applied using a commercially available coating device such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a microgravure coater, a rod blade coater, a lip coater, a die coater, and a curtain coater. be able to.

The coating amount of the pressure-sensitive adhesive composition is not particularly limited and can be appropriately set according to the target thickness of the pressure-sensitive adhesive layer. For example, the coating amount of the pressure-sensitive adhesive composition can be adjusted so that the thickness of the pressure-sensitive adhesive layer formed after the drying treatment described below is 5 to 1000 μm.

The type of base material for applying the pressure-sensitive adhesive composition is not particularly limited, and the base material used for forming the pressure-sensitive adhesive layer can be widely used. For example, a release sheet can be mentioned as a base material for applying the pressure-sensitive adhesive composition.

Examples of the release sheet include so-called separators used for protecting the adhesive layer in the pressure-sensitive adhesive sheet. More specifically, examples of the release sheet include a resin film having a release layer.

In the release sheet, examples of the resin film include a polyethylene terephthalate film and the like.

The release layer is a layer formed on at least one surface of the resin film, has a peeling force smaller than the adhesive force of the pressure-sensitive adhesive layer, and is formed so that the release sheet can be easily peeled off. It means that it is a layer. For such a release layer, for example, known components used as a release layer in an adhesive sheet can be widely applied. For example, the release layer can be formed of a known silicone material.

When the release sheet is used as the substrate, the pressure-sensitive adhesive composition can be applied to the release layer surface of the release sheet to form a coating film of the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive layer is formed on the base material by applying the pressure-sensitive adhesive composition onto the base material such as the release sheet to form a coating film and then performing a drying treatment.

The conditions of the drying treatment are not particularly limited, and, for example, a conventionally used method for drying the coating film of the pressure-sensitive adhesive composition can be widely adopted. Such a drying process can be performed using, for example, a known heating device. The heating temperature can be, for example, 50 to 200°C, and preferably 60 to 150°C. The heating time may be set so that the solvent is volatilized and the residual solvent concentration of the pressure-sensitive adhesive layer is, for example, 1000 ppm or less. It is preferable to set appropriately within a time of about 1 to 30 minutes.

A protective layer for protecting the adhesive layer can be further attached to the pressure-sensitive adhesive layer formed by the drying treatment. In this case, the protective layer is attached to the surface of the adhesive layer opposite to the base material. As the protective layer, for example, a release sheet can be used as described above. As for the release sheet as the protective layer, as in the case of the base material, a resin film having a release layer and the like can be mentioned. As the resin film, for example, a polyethylene terephthalate film and the like can be mentioned as in the above, and the release layer can be formed of, for example, a known silicone material.

When the base material and the protective layer are both release sheets (first release sheet and second release sheet, respectively), the release force of the release layer of the release sheet (first release sheet) as the base material, It is preferable that it is different from the adhesive force of the release layer of the release sheet (second release sheet) for forming the protective layer. That is, when the base material and the protective layer are both release sheets, it is preferable that the release sheets have different release forces. In this case, it becomes easy to selectively peel off only one of the release sheets when peeling off the release sheet, and it is easy to suppress the so-called tearing phenomenon.

After forming the pressure-sensitive adhesive layer and, if necessary, the protective layer as described above, aging treatment can be appropriately performed. The method of aging treatment is not particularly limited, and examples thereof include a method of allowing the pressure-sensitive adhesive layer to stand in an atmosphere of 15 to 50°C. The aging time can be appropriately set depending on the temperature, and can be, for example, 1 day to 10 days.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be set as appropriate according to the intended use and the like. For example, the pressure-sensitive adhesive layer may have a thickness of 5 to 200 μm, preferably 5 to 100 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 25 μm.

(Physical properties of adhesive layer)
As described above, the pressure-sensitive adhesive layer of the present invention has the following physical properties (1) and (2) when the pressure-sensitive adhesive layer is post-cured by irradiation with active energy rays so that the integrated light amount becomes 3000 mJ/cm ^2. Fulfill.
Physical Properties (1): In a tensile test measurement at a tensile speed of 10 mm/min, the breaking elongation is 1200% or more, and the stress at a strain of 1000% is 0.40 N/mm ² or more.
Physical properties (2): Water vapor permeability at a thickness of 100 μm is 50 g/m ² ·24 hr or less.
When the pressure-sensitive adhesive layer satisfies the above physical properties (1) and (2), the pressure-sensitive adhesive layer after curing (after post-effect) can have excellent low moisture permeability and durability.

In measuring the above physical properties, examples of the active energy ray with which the pressure-sensitive adhesive layer is irradiated include ultraviolet rays, electron rays, visible rays, X rays, and ion rays. Among them, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable, from the viewpoint of versatility. As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, an electrodeless ultraviolet lamp, or the like can be used. As the electron beam, for example, an electron beam emitted from various electron beam accelerators such as Cockloft-Walt type, Bande-Clough type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type can be used.

<Physical properties (1)>
In the physical properties (1), the measurement conditions of the tensile test are based on JIS K7161-1. This makes it possible to measure the elongation at break and the stress at a strain of 1000%. Specifically, this tensile test is performed under the environment of 23° C. and relative humidity of 50% at a tensile speed of 10 mm/min. Further, the measurement sample is used by processing a post-cured pressure-sensitive adhesive layer having a thickness of 20 μm, a width of 60 mm, and a length of 250 mm into a columnar shape having a cross-sectional area of 5 mm ² and a height of 60 mm by rolling in the length direction. The sample is set and pulled so that the distance between chucks is 30 mm, and the stress value when the strain of the measurement sample becomes 1000% and the elongation at break of the measurement sample (breaking elongation) are measured. Shimadzu Corporation Autograph AGS-X is used for the tensile test.

In the physical properties (1), the breaking elongation of the pressure-sensitive adhesive layer after irradiation with active energy rays is 1200% or more, and the stress at strain 1000% of the pressure-sensitive adhesive layer after irradiation with active energy rays is 0.40 N/mm. ^When it is ² or more, the pressure-sensitive adhesive layer can provide excellent durability.

In the physical property (1), the breaking elongation is preferably 1250% or more, more preferably 1300% or more. In the physical property (1), the upper limit of the breaking elongation is not particularly limited, but the breaking elongation is usually 2000% or less.

In the physical property (1), the elongation at break is 1200% or more, and the stress at a strain of 1000% is 0.40 N/mm ² or more, whereby the pressure-sensitive adhesive layer can bring excellent durability. ..

In Physical Properties (1), it is preferable that the stress at 1000% strain is 0.45N / mm ² or more, more preferably 0.5 N / mm ² or more. In the physical property (1), the upper limit of the stress at 1000% strain is not particularly limited, but the stress at 1000% strain is usually 3.0 N/mm ² or less.

In the pressure-sensitive adhesive layer, the stress at a strain of 1000% before irradiation with active energy rays is, for example, 0.01 to 0.30 N/mm ² .

Since the pressure-sensitive adhesive layer of the present invention is formed using a pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction type initiator, it can satisfy the physical properties (1). .. By adjusting the types and amounts of the polyolefin and (meth)acrylic monomers and the hydrogen abstraction type initiator in the pressure-sensitive adhesive composition, the elongation at break and the stress at a strain of 1000% in the physical properties (1) are appropriately adjusted. Can be controlled.

<Physical properties (2)>
In the physical properties (2), for the water vapor permeability (g/m ² ·24 hr), refer to the method described in Japanese Patent No. 5089809. Specifically, the moisture permeability is measured by the following method.
A pressure-sensitive adhesive layer after post-curing having a thickness of 100 μm is laminated on a backing material (“BEMCOT M-1” manufactured by Asahi Kasei Corp.) to obtain a sample for measuring water vapor transmission rate. The top of a glass jar or glass bottle with an opening having a diameter of 2.54 cm (hereinafter, referred to as a “glass container”) containing 50 g of distilled water in which a weight of up to three decimal places is accurately weighed Then, the adhesive layer is installed so as to face the bottom side of the glass container. While holding the pressure-sensitive adhesive layer in place with an open ring cover, after sealing the inside of the glass container with the pressure-sensitive adhesive layer so as to prevent water vapor and the like from leaking to the outside from the gap, the glass container (comprising the pressure-sensitive adhesive layer The glass container) is placed in an oven set at 40° C. with a relative humidity of 20% for about 24 hours with the glass container standing upright (where water does not touch the sample). Then, the weight loss of the glass container provided with the adhesive layer is measured, and the moisture vapor transmission rate (g/m ² ·24 hr) is calculated from the weight loss. The thickness (100 μm) of the pressure-sensitive adhesive layer is estimated from the coating amount of the pressure-sensitive adhesive composition.

In the physical property (2), the moisture permeability of the pressure-sensitive adhesive layer having a thickness of 100 μm after irradiation with active energy rays is 50 g/m ² ·24 hr or less, so that the pressure-sensitive adhesive layer can provide low moisture permeability. This makes it possible to apply the pressure-sensitive adhesive layer to applications where low moisture permeability is required.

In the physical property (2), the water vapor permeability is preferably 45 g/m ² ·24 hr or less, and more preferably 30 g/m ² ·24 hr or less. In the physical property (2), the lower limit of the water vapor transmission rate is not particularly limited, but the water vapor transmission rate is usually 1 g/m ² ·24 hr or more.

Since the pressure-sensitive adhesive layer of the present invention is formed using a pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction type initiator, it can satisfy the physical properties (2). .. In addition, by adjusting the content ratio of the polyolefin in the pressure-sensitive adhesive composition, it is possible to appropriately control the value of the water vapor transmission rate in the physical property (2).

(Other physical properties)
The pressure-sensitive adhesive layer of the present invention preferably has a relative dielectric constant of 3.0 or less when the pressure-sensitive adhesive layer is post-cured by irradiation with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² . In this case, the pressure-sensitive adhesive layer can be suitably used for bonding applications such as various image display devices. The relative dielectric constant when the pressure-sensitive adhesive layer is post-cured can be adjusted within an appropriate range by using, for example, a pressure-sensitive adhesive composition containing polyolefin.

The relative dielectric constant of the pressure-sensitive adhesive layer can be measured by the following procedure. The pressure-sensitive adhesive layer (those obtained by peeling the first release sheet and the second release sheet from the pressure-sensitive adhesive sheet) is sandwiched between two copper foils, and an autoclave treatment (40° C., 0.5 MPa, 30 minutes) is performed. .. After that, the relative permittivity is measured based on JIS C 2138 with a dielectric measuring system (1260 type, manufactured by Toyo Technica Co., Ltd.). In the measurement of the relative permittivity, the frequency is 1 MHz, the measurement environment is 23° C., and the relative humidity is 50%.

The pressure-sensitive adhesive layer has a gel fraction of 10 to 70%, the post-curing pressure-sensitive adhesive layer has a gel fraction of 60 to 100%, and the post-curing pressure-sensitive adhesive layer has a gel fraction of 60 to 100%. It is preferably 10% or more higher than the gel fraction before post-curing. In this case, the pressure-sensitive adhesive layer after curing can have excellent base material adhesion and excellent durability.

The shear storage elastic modulus G′ at 23° C. of the pressure-sensitive adhesive layer is, for example, 1.0×10 ^{5 to} 8.0× from the viewpoint that the durability of the pressure-sensitive adhesive layer is easily improved and peeling and bubble generation are less likely to occur. It can be in the range of 10 ⁶ . Further, the shear storage elastic modulus G′ at 85° C. of the pressure-sensitive adhesive layer can be set, for example, in the range of 1.0×10 ^{4 to} 8.0×10 ⁴ .

2. Adhesive Sheet The adhesive sheet of the present invention may be formed of only an adhesive layer, or may have other layers as necessary. The other layer can be formed on one side or both sides of the pressure-sensitive adhesive layer. Examples of the other layer include the release sheet described above. When the release sheets are formed on both surfaces of the pressure-sensitive adhesive layer, both release sheets (the first release sheet and the second release sheet) can have different release forces as described above.

For example, in the method for forming the pressure-sensitive adhesive layer described above, when the release sheet is used as the base material and the release sheet is also used as the protective layer, the pressure-sensitive adhesive sheet having the release sheet on both sides of the pressure-sensitive adhesive layer (release layer Directly attached adhesive sheet). After forming the pressure-sensitive adhesive layer, a release sheet may be separately provided on both surfaces of the pressure-sensitive adhesive layer to obtain a pressure-sensitive adhesive sheet with a release layer.

When the pressure-sensitive adhesive sheet has a release sheet, these release sheets can have a function as a so-called separator in the pressure-sensitive adhesive sheet.

When the pressure-sensitive adhesive sheet includes a release sheet, the thickness of the release sheet is not particularly limited. For example, the thickness of the release sheet can be 5 to 300 μm, and preferably 10 to 150 μm. The release sheets on both sides of the adhesive layer may have different thicknesses.

FIG. 1 is an example of an embodiment of a pressure-sensitive adhesive sheet, and is a schematic cross-sectional view. As shown in FIG. 1, the pressure-sensitive adhesive sheet can include a transparent substrate 12 a on one surface of the pressure-sensitive adhesive layer 11. In this case, the other surface of the adhesive layer 11 is preferably covered with the release sheet 12b. When using a pressure-sensitive adhesive sheet, the release sheet 12b is peeled off and the pressure-sensitive adhesive layer 11 is adhered to a desired adherend so that the pressure-sensitive adhesive layer 11 is adhered to the adherend, and then post-curing is performed by irradiating with active energy rays as described later. Is preferred. As the transparent substrate, a general film used in the optical field such as a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a triacetyl cellulose film, a cycloolefin polymer film can be used. Further, an easy adhesion layer may be provided on the adhesive layer side of these transparent substrates. Further, a functional layer such as a hard coat layer, an antireflection layer, an antifouling layer, and an ultraviolet absorbing layer may be provided on the surface of the transparent substrate opposite to the adhesive layer.

The pressure-sensitive adhesive sheet can be provided with release sheets on both surfaces thereof. When the release sheet is provided on both surfaces of the pressure-sensitive adhesive sheet, it is preferable to have release sheets 12a and 12b on both surfaces of the pressure-sensitive adhesive layer 11 as shown in FIG.

<How to use the adhesive sheet (post-curing method)>
The pressure-sensitive adhesive sheet can be widely used for applications in which members (adherends) such as substrates and films are adhered to each other.

For example, by interposing an adhesive sheet between a pair of adherends, adhering the adherends to each other with the adhesive sheet to form a laminated body, and “post-curing” the adherends to each other with the adhesive sheet. Can be combined. When the pressure-sensitive adhesive sheet includes a release sheet, the pressure-sensitive adhesive sheet is interposed between the pair of adherends with the release sheet peeled off.

The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet is irradiated with active energy rays and post-cured, so that the hydrogen abstraction-type initiator abstracts hydrogen of the (meth)acrylic monomer, whereby the crosslinking reaction can proceed. Thereby, the curing of the pressure-sensitive adhesive layer further progresses, and the adherends are more firmly adhered to each other by the curing of the pressure-sensitive adhesive layer.

Here, the method of post-curing the pressure-sensitive adhesive layer is not particularly limited, and, for example, known curing methods can be widely adopted. Specifically, the adhesive layer can be post-cured by irradiating the adhesive layer with active energy rays. It should be noted that the post-curing conditions for using the pressure-sensitive adhesive sheet in various applications are limited to the post-curing conditions for measuring the above-mentioned physical properties (1) and (2), just as a precautionary note. It is not something that will be done.

Examples of the active energy rays include ultraviolet rays, electron rays, visible rays, X rays, and ion rays. Among them, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable, from the viewpoint of versatility. As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, an electrodeless ultraviolet lamp, or the like can be used. As the electron beam, for example, an electron beam emitted from various electron beam accelerators such as Cockloft-Walt type, Bande-Clough type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type can be used.

Integrated light quantity of the active energy ray irradiation, for example 500~10000mJ / cm ^2, preferably 1000~8000mJ / cm ^2, more preferably 1500~6000mJ / cm ^2.

The method of irradiating the active energy ray is not particularly limited, and for example, the entire surface of the laminate formed by adhering adherends with an adhesive sheet can be irradiated with the active energy ray. From this viewpoint, at least one of the adherends is preferably transparent. For irradiation with the active energy ray, for example, a known active energy ray irradiation device can be used.

<Use of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention is an optical member that requires durability, and is preferably used for bonding an optical member that has a complicated shape and that requires punching after forming a laminated body.

The pressure-sensitive adhesive sheet of the present invention is excellent in durability even when exposed to a high-temperature and high-humidity environment after being attached to an adherend such as a base material and post-cured, and therefore, it does not float or peel off. Can be suppressed. The pressure-sensitive adhesive sheet of the present invention is, for example, attached to a polycarbonate film, and after being post-cured, even when exposed to a high temperature and high humidity environment, it is prevented from floating or peeling from the polycarbonate film. You can

The pressure-sensitive adhesive sheet of the present invention may be attached to an optical member such as a polarizing plate. Here, the polarizing plate includes a polarizer and a polarizer protective film, and the pressure-sensitive adhesive sheet of the present invention is preferably attached to the polarizer protective film. As the polarizer protective film, cycloolefin resin film, cellulose acetate resin film such as triacetyl cellulose and diacetyl cellulose, polyester resin film such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, polycarbonate resin film, acrylic Examples thereof include a resin resin film and a polypropylene resin film.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, it can be used for bonding two adherends. In this case, the pressure-sensitive adhesive sheet of the present invention includes bonding of transparent optical films to each other inside a touch panel, bonding of transparent optical film and glass, bonding of transparent optical film of touch panel and liquid crystal panel, cover glass. And a transparent optical film, or a cover glass and a transparent optical film, and is useful when either member is a polycarbonate substrate. As the transparent optical film, a general film used in the optical field such as a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a triacetyl cellulose film, or a cycloolefin polymer film can be used. A hard coat layer may be provided on the transparent optical film or the polycarbonate substrate.

INDUSTRIAL APPLICABILITY The pressure-sensitive adhesive sheet of the present invention has low moisture permeability and excellent durability, and thus can be widely applied to various image display devices and the like. ) Etc. can be used suitably.

2. Laminated body The laminated body includes the above-mentioned pressure-sensitive adhesive sheet or a cured product thereof. When the pressure-sensitive adhesive sheet includes a release sheet, the release sheet is present in the laminated body in a peeled state. That is, it can be said that the laminate has the pressure-sensitive adhesive layer.

The laminate can be provided with adherends on both sides of the adhesive sheet. When the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, two adherends are pasted with the pressure-sensitive adhesive sheet before post-curing to irradiate active energy rays, and the pressure-sensitive adhesive layer is post-cured to form a laminate. It is preferable. Here, the adherend is more preferably a substrate and an optical member, and particularly preferably a polycarbonate film, a polarizing plate, a transparent film, a transparent resin or glass.

FIG. 2 is a schematic view showing a cross section of an example of the laminated body. FIG. 2 is a cross-sectional view showing an example of the configuration of the laminate 20 in which the pressure-sensitive adhesive sheet 21 of the present invention is attached to the base material 22 and the optical member 24. As shown in FIG. 2, the pressure-sensitive adhesive sheet 21 of the present invention is preferably used for bonding to the base material 22, and is used for bonding the base material 22 and the other optical member 24. preferable. The pressure-sensitive adhesive sheet 21 of the present invention may be used for bonding with a polarizing plate.

Examples of the optical member included in the laminated body include various constituent members in optical products such as a touch panel and an image display device, and an anti-scattering film attached to the cover lens of the outermost layer. As a component of the touch panel, for example, an ITO film provided with an ITO film on a transparent resin film, an ITO glass provided with an ITO film on the surface of a glass plate, a transparent conductive film obtained by coating a conductive polymer on a transparent resin film, A hard coat film, a fingerprint resistant film and the like can be mentioned. Examples of constituent members of the image display device include an antireflection film, an alignment film, a polarizing film, a retardation film, and a brightness enhancement film used in a liquid crystal display device.

Examples of materials used for these members include glass, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyethylene naphthalate, cycloolefin polymer, triacetyl cellulose, polyimide, and cellulose acylate.

As described above, the laminate is a step of laminating the adherend on at least one surface side of the pressure-sensitive adhesive sheet, and post-curing the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays. It can be obtained by a manufacturing method including a step of

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the modes of these examples.

Preparation Example of Adhesive Composition (Preparation Example 1)
100 parts by mass of ethylene/propylene rubber (“T7241” manufactured by JSR) as a polyolefin, 50 parts by mass of “FTR8120” manufactured by Mitsui Chemicals, Inc. as a tackifier, and “light” manufactured by Kyoeisha Chemical Co., Ltd. as an acrylic polyfunctional monomer. 3 parts by mass of acrylate DCP-A" (dimethyloltricyclodecane diacrylate), 3 parts by mass of "IBXA" (isobornyl acrylate) manufactured by Osaka Organic Chemical Industry as an acrylic monofunctional monomer, and hydrogen abstraction An adhesive composition was obtained by mixing 1 part by mass of "4MBP" (4-methylbenzophenone) manufactured by LAMBSON Co., Ltd. as a mold initiator.

(Preparation example 2)
A pressure-sensitive adhesive composition was obtained in the same manner as in Preparation Example 1 except that the acrylic polyfunctional monomer was changed to bisphenol A ethylene oxide-modified diacrylate (Aronix M-211B manufactured by Toagosei Co., Ltd.).

(Preparation example 3)
An adhesive composition was obtained in the same manner as in Preparation Example 1 except that the amounts of the acrylic polyfunctional monomer and the acrylic monofunctional monomer were both changed to 5 parts by mass.

(Preparation example 4)
A pressure-sensitive adhesive composition was obtained in the same manner as in Preparation Example 3, except that the addition amounts of both the acrylic polyfunctional monomer and the acrylic monofunctional monomer were changed to 5 parts by mass.

(Preparation example 5)
An adhesive composition was obtained in the same manner as in Preparation Example 1 except that the addition amounts of both the acrylic polyfunctional monomer and the acrylic monofunctional monomer were changed to 15 parts by mass.

(Preparation example 6)
An adhesive composition was obtained in the same manner as in Preparation Example 1 except that the acrylic polyfunctional monomer, the acrylic monofunctional monomer and the hydrogen abstraction initiator were not used.

(Preparation example 7)
100 parts by mass of "SK2094" manufactured by Soken Chemical Industry Co., Ltd. as an acrylic polymer, 50 parts by mass of "FTR8120" manufactured by Mitsui Chemicals Co., Ltd. as a tackifier, and 1 mass of "4MBP" manufactured by LAMBSON as a hydrogen abstraction initiator. A pressure-sensitive adhesive composition was obtained by mixing each of these parts with each other.

Formation of adhesive layer (preparation of adhesive sheet)
(Example 1)
A pressure-sensitive adhesive layer was formed using the pressure-sensitive adhesive composition obtained in Preparation Example 1. As the first release sheet, a polyethylene terephthalate film having a thickness of 100 μm and provided with an easily adhesive layer treated with a silicone release agent (heavy separator film, manufactured by Teijin DuPont Films Ltd., release-treated polyethylene terephthalate film) ) Prepared. The pressure-sensitive adhesive composition obtained in Preparation Example 1 was applied to the surface of the first release sheet on the easy-adhesive layer side so that the coating thickness after drying would be a desired value (20 μm or 100 μm). Coated evenly with "Dr. Blade YD type" manufactured by Co., Ltd. to prepare a coating film of the pressure-sensitive adhesive composition, and then dried for 3 minutes in an air-circulating constant temperature oven at 100° C. for the first peeling. An adhesive layer was formed on the surface of the sheet.

Then, a second release sheet having a thickness of 75 μm and subjected to a release treatment having higher release property than the first release sheet (light separator film, manufactured by Teijin DuPont Films Ltd., release-treated polyethylene terephthalate film) Prepared. This second release sheet was laminated on the pressure-sensitive adhesive layer formed on the surface of the first release sheet. Thereby, the pressure-sensitive adhesive sheet with the release sheet having the structure of the first release sheet/the pressure-sensitive adhesive layer (A-1)/the second release sheet in which the pressure-sensitive adhesive layer is sandwiched between the pair of release sheets having different release forces is obtained. Was obtained.

(Example 2)
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 2.

(Example 3)
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 3.

(Example 4)
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 4.

(Comparative Example 1)
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 5.

(Comparative example 2)
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 6.

(Comparative example 3)
The pressure-sensitive adhesive composition obtained in Preparation Example 1 was changed to the pressure-sensitive adhesive composition obtained in Preparation Example 7, and the pressure-sensitive adhesive sheet with a release sheet was allowed to stand for 7 days at 23° C. and 50% relative humidity, A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the aging treatment was performed.

(Evaluation method)
<Tensile test measurement>
In the tensile test, the breaking elongation of the pressure-sensitive adhesive layer and the stress at a strain of 1000% were measured according to JIS K7161-1. Specifically, in the tensile test, the tensile speed was set to 10 mm/min, and measurement was performed in an environment of 23° C. and relative humidity of 50%. The measurement sample was used by processing a post-cured pressure-sensitive adhesive layer having a thickness of 20 μm, a width of 60 mm, and a length of 250 mm into a columnar shape having a cross-sectional area of 5 mm ² and a height of 60 mm by rolling in the length direction. The sample was set and pulled so that the distance between chucks was 30 mm, and the stress value when the strain of the measurement sample was 1000% and the elongation at break of the measurement sample (breaking elongation) were measured. Shimadzu autograph AGS-X was used for the tensile test.

<Measurement of moisture permeability>
For the moisture vapor transmission rate (g/m ² ·24 hr), refer to the method described in Japanese Patent No. 5089809. Specifically, the water vapor permeability was measured by the following method.
A pressure-sensitive adhesive layer after post-curing having a thickness of 100 μm was laminated on a backing material (“BEMCOT M-1” manufactured by Asahi Kasei Corp.) to obtain a sample for measuring moisture permeability. This sample is placed on the top of a glass bottle with an opening having a diameter of 2.54 cm and containing 50 g of distilled water in which the weight up to three decimal places is accurately weighed, and the adhesive layer faces the bottom side of the glass bottle. Was installed. While holding the pressure-sensitive adhesive layer in place with an open ring cover, the inside of the glass container was sealed with the pressure-sensitive adhesive layer so that water vapor and the like would not leak to the outside from the gap, and then this glass bottle (including the pressure-sensitive adhesive layer The glass bottle) was placed in an oven set at 40° C. with a relative humidity of 20% for about 24 hours with the glass bottle standing upright (where water does not touch the sample). Then, the weight loss of the glass bottle provided with the adhesive layer was measured, and the moisture vapor transmission rate (g/m ² ·24 hr) was calculated from the weight loss. The thickness (100 μm) of the pressure-sensitive adhesive layer was estimated from the coating amount of the pressure-sensitive adhesive composition.

<Durability>
The second release sheet, which is a light separator film for the pressure-sensitive adhesive layer, was peeled off and attached to a polarizing plate (SKN-18243T manufactured by Polatechno Co., Ltd.). Next, the first release sheet, which is a heavy separator film, was peeled off and attached to a PC film (Pure Ace GS manufactured by Teijin Ltd.). The sample having the configuration of polarizing plate/adhesive layer/PC film was autoclaved (40° C., 0.5 MPa, 30 min), and then irradiated with ultraviolet rays from the PC film side so that the integrated light amount was 3000 mJ/cm ² . A test sample with a size of 100 mm×200 mm was obtained. Then, the test sample was left to stand in an environment of 60° C. and 95% relative humidity for 240 hours. Then, the test sample was observed, and the presence or absence of floating and peeling was observed, and each was evaluated according to the following criteria.
<<Bubbles>>
◯: No generation of bubbles having a maximum length of 0.2 mm or more was observed.
X: Generation of bubbles having a maximum length of 0.2 mm or more was observed.
≪Peeling off≫
◯: No peeling of 1.0 mm or more was observed.
X: Peeling of 1.0 mm or more was observed.

<Measurement of shear storage elastic modulus G'>
The shear storage elastic modulus G′ was measured using a dynamic viscoelastic device Rheogel-E4000 (manufactured by UBM Co., Ltd.). The shear storage elastic modulus G′ of the pressure-sensitive adhesive layer in the temperature range from 20° C. to 120° C. was measured under the conditions of solid shear mode, frequency 1 Hz, and strain 1.0%, and the shear storage elastic modulus at 23° C. and 85° C. The value of G'was calculated. The measurement was performed after irradiating the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples with ultraviolet rays so that the integrated light amount was 3000 mJ/cm ² with the separator attached, and post-curing.

(Evaluation results)
Table 1 shows the components and the content ratios of the pressure-sensitive adhesive compositions used in each example and comparative example. In addition, Table 1 shows the shear storage elastic modulus G′, the moisture permeability, the tensile test result, and the durability evaluation result of the pressure-sensitive adhesive layers obtained in each Example and Comparative Example.

The pressure-sensitive adhesive sheets obtained in the respective examples had low moisture permeability and were resistant to bubbles and peeling, and thus had excellent durability. On the other hand, in the pressure-sensitive adhesive sheet of Comparative Example 1, since the (meth)acrylic monomer contained in the pressure-sensitive adhesive layer was too much, low moisture permeability could not be obtained, and peeling easily occurred. Since the pressure-sensitive adhesive sheet of Comparative Example 2 did not contain a (meth)acrylic monomer, the stress at an elongation of 1000% was small and air bubbles were easily generated. In the pressure-sensitive adhesive sheet of Comparative Example 3, since the pressure-sensitive adhesive layer did not contain polyolefin, the physical properties (1) and (2) could not be satisfied, and the durability was poor.

Claims (8)

A pressure-sensitive adhesive composition containing a polyolefin, a (meth)acrylic monomer, and a hydrogen abstraction-type initiator,
The (meth)acrylic monomer is a mixture of a polyfunctional monomer having two or more polymerizable functional groups in the molecule and a monofunctional monomer having only one polymerizable functional group in the molecule,
The following physical properties (1) and (2) are obtained when the active energy ray is irradiated so that the integrated light amount becomes 3000 mJ/cm ² and post-cured.
Physical properties (1): In a tensile test measurement at a tensile speed of 10 mm/min, the breaking elongation is 1200% or more, and the stress at a strain of 1000% is 0.40 N/mm ² or more,
Physical properties (2): Water vapor permeability at a thickness of 100 μm is 50 g/m ² ·24 hr or less,
Adhesive layer that fills. The pressure-sensitive adhesive layer according to claim 1, wherein the polyolefin is an ethylene-propylene copolymer. The pressure-sensitive adhesive layer according to claim 1 or 2, wherein the (meth)acrylic monomer contained in the pressure-sensitive adhesive composition is 1 to 25 parts by mass with respect to 100 parts by mass of the polyolefin. Relative dielectric constant of 3.0 or less, the pressure-sensitive adhesive layer according to any one of claims 1-3. Thickness of 5 to 200 [mu] m, the pressure-sensitive adhesive layer according to any one of claims 1-4. Comprising a pressure-sensitive adhesive layer according to any one of claims 1 to 5 pressure-sensitive adhesive sheet. A laminate comprising the adhesive sheet according to claim 6 or a cured product thereof. A step of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet according to claim 6 , and a step of post-curing the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays. A method for manufacturing a laminate, which has in order.