KR102580624B1 - Rubber-based adhesive composition, rubber-based adhesive layer, optical film having a rubber-based adhesive layer, optical member, image display device, and method for producing the rubber-based adhesive layer - Google Patents

Abstract

The rubber-based adhesive composition of the present invention contains polyisobutylene and a hydrogen abstraction type photopolymerization initiator. According to the rubber-based adhesive composition of the present invention, it is possible to form a rubber-based adhesive layer with low moisture permeability and high durability that can suppress the occurrence of problems such as lifting and peeling even under a high temperature environment.

Description

Rubber-based adhesive composition, rubber-based adhesive layer, optical film having a rubber-based adhesive layer, optical member, image display device, and method for producing the rubber-based adhesive layer

The present invention relates to a rubber-based adhesive composition and a rubber-based adhesive layer formed from the rubber-based adhesive composition. Furthermore, the present invention relates to an optical film having a rubber-based adhesive layer in which the rubber-based adhesive layer is formed on an optical film, and an optical member including the optical film having the rubber-based adhesive layer. Additionally, the present invention relates to an image display device including an optical film and/or an optical member having the pressure-sensitive adhesive layer. Additionally, the present invention relates to a method for producing a rubber-based adhesive layer.

In recent years, in image display devices such as liquid crystal displays, there is a strong demand for reduction in weight and thickness, and there is a demand for reduction in thickness and weight for various optical members such as polarizing films used in image display devices.

For example, as a polarizing film, a one-sided protective polarizing film having a protective film only on one side of the polarizer is known. Although such a single-sided protective polarizing film can be made thinner and lighter, there is a problem in that it is easily deteriorated by moisture or the like because one side of the polarizer is not protected by the protective film. In addition, even in a double-sided protective polarizing film, when the protective film is thinned, the polarizer may similarly deteriorate due to moisture or the like.

In addition, since the organic EL panel mounted on an organic EL (Electro Luminescence) display device is very vulnerable to moisture and oxygen in the atmosphere, a barrier layer or an optical film with a barrier function is usually provided on the surface of the organic EL panel. The adhesive layer for joining them is also required to not transmit moisture, etc. (low moisture permeability).

In this way, various optical members used in image display devices are susceptible to deterioration due to moisture, etc., depending on their materials, and the adhesive layer for bonding the optical member to the adherend must not allow moisture, etc. to penetrate (low moisture permeability) ) was being requested.

As a material for forming such a low moisture permeability adhesive layer, for example, an adhesive encapsulation composition containing a hydrogenated cyclic olefin polymer and a polyisobutylene resin (see, for example, Patent Document 1), an adhesive having an unsaturated bond. A conjugated diene-based uncrosslinked rubber, a crosslinked rubber composition containing a hydrogen abstraction type photopolymerization initiator (for example, see Patent Document 2), an adhesive composition with high barrier properties containing a butyl-based rubber containing a specific amount of isoprene (e.g. For example, see Patent Document 3), etc. are known.

Japanese Patent Publication No. 2009-524705 Japanese Patent Publication No. 2010-180370 Japanese Patent Publication No. 2015-522664

Although the adhesives of Patent Documents 1 to 3 are described as having moisture barrier properties, gas barrier properties, etc., when the adhesive layers described in these documents are stored in a high temperature environment, problems such as lifting and peeling occur. There was. This does not examine crosslinking of rubber-based resins in Patent Document 1, and crosslinking of rubber is described in Patent Documents 2 and 3. However, this refers to crosslinking rubber having unsaturated bonds, thereby eliminating the unsaturated bonds in the rubber. It is a bridge using . In such crosslinking, if there are few unsaturated bonds, the crosslinking density is low and durability is not improved, and if there are many unsaturated bonds, the remaining unsaturated bonds are degraded by sunlight, etc., causing yellowing or main chain breakage, which is a practical problem. There was.

Therefore, the purpose of the present invention is to provide a rubber-based adhesive composition capable of forming a rubber-based adhesive layer with low moisture permeability and high durability that can suppress the occurrence of problems such as lifting and peeling even under a high temperature environment. Furthermore, the present invention aims to provide an optical member including a rubber-based adhesive layer formed from the adhesive composition, an optical film having an adhesive layer provided with the rubber-based adhesive layer, and an optical film having the rubber-based adhesive layer. Another object is to provide an image display device comprising at least one selected from the group consisting of the optical film having the rubber-based adhesive layer and the optical member. Another object is to provide a method for manufacturing the rubber-based adhesive layer.

As a result of intensive studies to solve the above problems, the present inventors have discovered the following rubber-based adhesive composition and completed the present invention.

That is, the present invention relates to a rubber-based adhesive composition characterized by comprising polyisobutylene and a hydrogen abstraction type photopolymerization initiator.

The rubber-based adhesive composition of the present invention preferably contains 20 parts by weight or less of a polyfunctional radically polymerizable compound based on 100 parts by weight of the polyisobutylene.

It is preferable that the polyfunctional radically polymerizable compound is a compound having at least two (meth)acryloyl groups.

The compound having at least two (meth)acryloyl groups is a bifunctional (meth)acrylate having two (meth)acryloyl groups and/or a trifunctional (meth)acrylate having three (meth)acryloyl groups. It is preferable that it is an acrylate.

It is preferable that the hydrogen abstraction type photopolymerization initiator is a benzophenone-based compound.

The content of the hydrogen abstraction type photopolymerization initiator is preferably 0.001 to 10 parts by weight based on 100 parts by weight of the polyisobutylene.

The rubber-based adhesive composition of the present invention preferably contains at least one type of tackifier selected from the group consisting of a tackifier containing a terpene skeleton, a tackifier containing a rosin skeleton, and hydrogenated substances thereof. .

The rubber-based adhesive composition of the present invention can be crosslinked by irradiation of active energy rays.

It is preferable that the active energy ray is an ultraviolet ray.

It is preferable that the moisture permeability of the rubber-based adhesive layer with a thickness of 50 μm formed from the above-mentioned rubber-based adhesive composition is 50 g/(m 2 ·day) or less at 40°C and 92% R.H.

Additionally, the present invention relates to a rubber-based adhesive layer characterized by being formed from the above-described rubber-based adhesive composition.

Furthermore, the present invention relates to an optical film having a rubber-based adhesive layer, characterized in that it has an optical film and the rubber-based adhesive layer provided on the optical film.

It is preferable that the optical film is a polarizing film having a protective film on at least one side of the polarizer.

It is preferable that the polarizing film is a single-sided protective polarizing film having a protective film on only one side of the polarizer, and that the rubber-based adhesive layer is laminated on the side of the polarizer that does not have a protective film.

It is preferable that the optical film is a brightness improving film.

Furthermore, the present invention relates to an optical member characterized by comprising the rubber-based adhesive layer and a film having a moisture permeability of 1 g/(m2·day) or less at 40°C and 92% R.H.

Furthermore, the present invention relates to an image display device comprising at least one member selected from the group consisting of the optical film having the rubber-based adhesive layer and the optical member.

Additionally, the present invention relates to a method for producing a rubber-based adhesive layer, which is obtained by crosslinking the rubber-based adhesive composition by irradiating active energy rays.

Since the rubber-based adhesive composition of the present invention contains polyisobutylene that does not contain a double bond in the main chain and a hydrogen abstraction type photopolymerization initiator, a crosslinked structure can be introduced by irradiating active energy rays and maintains low moisture permeability. While doing so, it is possible to provide a rubber-based adhesive layer (having high durability) that can suppress the occurrence of problems (such as lifting or peeling) even in a high-temperature environment.

Furthermore, the present invention can provide an optical film, an optical member, and an image display device with excellent optical reliability that have a rubber-based adhesive layer that is excellent in durability under a high temperature environment and has excellent low moisture permeability. Additionally, the present invention can provide a method for producing a rubber-based adhesive layer that exhibits the above excellent effects.

1 is a cross-sectional view schematically showing a polarizing film with an adhesive layer according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view schematically showing one embodiment of the optical member of the present invention.
Fig. 3 is a cross-sectional view schematically showing one embodiment of the optical member of the present invention.

1. Rubber-based adhesive composition

The rubber-based adhesive composition of the present invention is characterized by containing polyisobutylene and a hydrogen abstraction type photopolymerization initiator.

(1) Polyisobutylene

The polyisobutylene (PIB) is a homopolymer of isobutylene, and commercial products such as OPPANOL manufactured by BASF, for example, can be used. In the present invention, since polyisobutylene containing no double bonds in the main chain is used, weather resistance is excellent.

The weight average molecular weight (Mw) of the polyisobutylene is preferably 100,000 or more, more preferably 300,000 or more, more preferably 600,000 or more, and especially preferably 700,000 or more. The upper limit of the weight average molecular weight is not particularly limited, but is preferably 5 million or less, more preferably 3 million or less, and even more preferably 2 million or less. By setting the weight average molecular weight of the polyisobutylene to 100,000 or more, a rubber-based adhesive composition can be made with more excellent durability when stored at high temperatures.

The content of the polyisobutylene is not particularly limited, but is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, based on the total solid content of the rubber-based adhesive composition. It is more preferable that it is more than 85% by weight, and it is especially preferable that it is 90% by weight or more. The upper limit of the content of polyisobutylene is not particularly limited, and is preferably 99% by weight or less, and more preferably 98% by weight or less. It is preferable to include polyisobutylene in the above range because it has excellent low moisture permeability.

Additionally, the rubber-based adhesive composition of the present invention may contain polymers or elastomers other than the polyisobutylene. Specifically, copolymers of isobutylene and normal butylene, copolymers of isobutylene and isoprene (e.g., butyl rubbers such as regular butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and partially cross-linked butyl rubber), Isobutylene-based polymers such as vulcanized products and modified products thereof (for example, those modified with functional groups such as hydroxyl group, carboxyl group, amino group, and epoxy group); Styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-propylene-styrene block copolymer ( SEPS, hydrogenated product of SIS), styrene-ethylene-propylene block copolymer (SEP, hydrogenated product of styrene-isoprene block copolymer), styrene-isobutylene-styrene block copolymer (SIBS), styrene-butadiene rubber (SBR) ) Styrene-based thermoplastic elastomers such as styrene-based block copolymers such as ); Butyl rubber (IIR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, polyurethane-based thermoplastic elastomer; Polyester-based thermoplastic elastomer; and blended thermoplastic elastomers such as a polymer blend of polypropylene and EPT (ternary ethylene-propylene rubber). These can be added in a range that does not impair the effect of the present invention, but the amount is preferably about 10 parts by weight or less with respect to 100 parts by weight of the polyisobutylene, and from the viewpoint of durability, it is preferable not to include them.

(2) Hydrogen extraction type photopolymerization initiator

A hydrogen abstraction type photopolymerization initiator is one that can extract hydrogen from the polyisobutylene and create a reaction site in the polyisobutylene by irradiating active energy rays without cleavage of the initiator itself. By forming the reaction point, the crosslinking reaction of polyisobutylene can be initiated.

As a photopolymerization initiator, in addition to the hydrogen abstraction type photopolymerization initiator used in the present invention, a cleavage type photopolymerization initiator in which the photopolymerization initiator itself undergoes cleavage decomposition to generate radicals by irradiation of active energy rays is also known. However, if a cleavage type photopolymerization initiator is used for the polyisobutylene used in the present invention, the main chain of the polyisobutylene is cut by the photopolymerization initiator generating radicals, and crosslinking is not possible. In the present invention, polyisobutylene can be crosslinked as described above by using a hydrogen abstraction type photopolymerization initiator.

Examples of the hydrogen abstraction type photopolymerization initiator include acetophenone, benzophenone, o-benzoylmethylbenzoate, 4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, and 4,4'-dimethoxybenzo. Phenone, 4,4'-dichlorobenzophenone, 4,4'-dimethylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra Benzophenone-based compounds such as (t-butylperoxycarbonyl)benzophenone and 3,3'-dimethyl-4-methoxybenzophenone; Thioxanthone-based compounds such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone; Amino benzophenone compounds such as 4,4'-bis(dimethylamino)benzophenone and 4,4'-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone, etc.; Aromatic ketone compounds such as acetonaphthone and 1-hydroxycyclohexylphenyl ketone; Aromatic aldehydes such as terephthalaldehyde, and quinone-based aromatic compounds such as methyl anthraquinone are included. These can be used individually or in mixture of two or more types. Among these, from the viewpoint of reactivity, benzophenone-based compounds are preferable, and benzophenone is more preferable.

The content of the hydrogen abstraction type photopolymerization initiator is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 10 parts by weight, and even more preferably 0.01 to 10 parts by weight, based on 100 parts by weight of the polyisobutylene. It is preferable to include the hydrogen abstraction type photopolymerization initiator in the above range because the crosslinking reaction can proceed to the desired density.

In addition, in the present invention, a cleavage type photopolymerization initiator may be used together with the hydrogen abstraction type photopolymerization initiator to the extent that the effect of the present invention is not impaired, but it is preferable not to use it for the reasons described above.

(3) Multifunctional radically polymerizable compounds

The rubber-based adhesive composition of the present invention may further include a polyfunctional radically polymerizable compound. In the present invention, the polyfunctional radically polymerizable compound functions as a crosslinking agent for polyisobutylene.

The polyfunctional radically polymerizable compound is a compound having at least two radically polymerizable functional groups having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Specific examples of polyfunctional radically polymerizable compounds include, for example, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9- Nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, Bisphenol A di(meth)acrylate, Bisphenol A ethylene Oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane Dimethanol di(meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di Esterates of (meth)acrylic acid and polyhydric alcohols such as pentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerol tetra(meth)acrylate, 9,9-bis[ 4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, etc. can be mentioned. These can be used individually or as a mixture of two or more types. Among these, from the viewpoint of compatibility with polyisobutylene, esters of (meth)acrylic acid and polyhydric alcohols are preferable, and bifunctional (meth)acrylates and (meth)acrylates having two (meth)acryloyl groups are preferable. A trifunctional (meth)acrylate having three loyl groups is more preferable, and tricyclodecane dimethanol di(meth)acrylate and trimethylolpropane tri(meth)acrylate are particularly preferable.

The content of the polyfunctional radically polymerizable compound is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less, based on 100 parts by weight of the polyisobutylene. In addition, the lower limit of the content of the polyfunctional radically polymerizable compound is not particularly limited, but for example, it is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, based on 100 parts by weight of the polyisobutylene, and 1 It is more preferable that it is more than parts by weight. It is preferable that the content of the polyfunctional radically polymerizable compound is within the above range from the viewpoint of durability of the obtained rubber-based adhesive layer.

The molecular weight of the polyfunctional radically polymerizable compound is not particularly limited, but for example, it is preferably about 1000 or less, and more preferably about 500 or less.

(4) Tackifier

The rubber-based adhesive composition of the present invention may contain at least one type of tackifier selected from the group consisting of a tackifier containing a terpene skeleton, a tackifier containing a rosin skeleton, and hydrogenated substances thereof. It is preferable to include a tackifier in the rubber-based adhesive composition because it is possible to form a rubber-based adhesive layer that has high adhesion to various adherends and has high durability even in a high-temperature environment.

Examples of the tackifier containing the terpene skeleton include terpene polymers such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and those obtained by modifying the terpene polymer (phenol modification, styrene modification, aromatic modification, hydrogenation). Modified terpene resins (modified, hydrocarbon-modified, etc.) can be mentioned. Examples of the modified terpene resin include terpene phenol resin, styrene-modified terpene resin, aromatic modified terpene resin, and hydrogenated terpene resin (hydrogenated terpene resin). Examples of hydrogenated terpene resins referred to herein include hydrides of terpene polymers, other modified terpene resins, and hydrogenated products of terpene phenol resins. Among these, hydrogenated products of terpene phenol resins are preferable from the viewpoint of compatibility with rubber-based adhesive compositions and adhesive properties.

Examples of the tackifier containing the rosin skeleton include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, and rosin phenol resin, and specifically, gum rosin and wood. Unmodified rosin (raw rosin) such as rosin and tall oil rosin, modified rosin that has been hydrogenated, sterilized, polymerized, or otherwise chemically modified, and their derivatives can be used.

Examples of the tackifier include commercially available products such as the Clearon series and Polystar series manufactured by Yasuhara Chemical Co., Ltd., and the Super Ester series, Pencel series and Fine Crystal series manufactured by Arakawa Chemical Co., Ltd. You can use it.

When the tackifier is a hydrogenated substance, the hydrogenation may be a partially hydrogenated substance, or a fully hydrogenated substance in which all double bonds in the compound are hydrogenated. In the present invention, it is preferable that it is a fully hydrogenated substance from the viewpoint of adhesive properties, weather resistance and color.

From the viewpoint of adhesive properties, it is preferable that the tackifier contains a cyclohexanol skeleton. Although the detailed principle of this is unclear, it is believed that the cyclohexanol skeleton is more balanced in compatibility with the base polymer, polyisobutylene, than the phenol skeleton. As a tackifier containing a cyclohexanol skeleton, for example, hydrogenated substances such as terpene phenol resin and rosin phenol resin are preferred, and fully hydrogenated substances such as terpene phenol resin and rosin phenol resin are more preferred.

The softening point (softening temperature) of the tackifier is not particularly limited, but for example, it is preferably about 80°C or higher, and more preferably about 100°C or higher. It is preferable that the softening point of the tackifier is 80°C or higher because the tackifier can maintain the adhesive properties without softening even at high temperatures. The upper limit of the softening point of the tackifier is not particularly limited, but if the softening point becomes too high, the molecular weight becomes higher, compatibility deteriorates, and problems such as whitening may occur, for example, 200°C or lower. It is preferable that it is about 180°C or less. In addition, the softening point of the tackifying resin referred to herein is defined as a value measured by the softening point test method (ring and ball method) specified in either JIS K5902 or JIS K2207.

The weight average molecular weight (Mw) of the tackifier is not particularly limited, but is preferably 50,000 or less, preferably 30,000 or less, more preferably 10,000 or less, still more preferably 8000 or less, and 5000 or less. This is particularly desirable. The lower limit of the weight average molecular weight of the tackifier is not particularly limited, but is preferably 500 or more, more preferably 1000 or more, and even more preferably 2000 or more. It is preferable that the weight average molecular weight of the tackifier is within the above range because it has good compatibility with polyisobutylene and does not cause problems such as whitening.

The amount of the tackifier added is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 20 parts by weight or less, based on 100 parts by weight of the polyisobutylene. The lower limit of the amount of tackifier added is not particularly limited, but is preferably 0.1 part by weight or more, more preferably 1 part by weight or more, and even more preferably 5 parts by weight or more. It is preferable that the amount of the tackifier used is within the above range because the adhesive properties can be improved. Additionally, if the amount of tackifier used exceeds the above range and is added in large quantities, the cohesive force of the tackifier tends to decrease, which is not preferable.

Additionally, a tackifier other than the tackifier containing a terpene skeleton and a rosin skeleton may be added to the rubber-based adhesive composition of the present invention. Examples of the tackifier include petroleum resin-based tackifiers. Examples of the petroleum-based tackifier include aromatic petroleum resin, aliphatic petroleum resin, alicyclic petroleum resin (aliphatic cyclic petroleum resin), aliphatic/aromatic petroleum resin, aliphatic/alicyclic petroleum resin, and hydrogenated petroleum resin. , coumarone-based resin, and coumarone-indene-based resin.

The petroleum resin-based tackifier can be used within a range that does not impair the effect of the present invention, but for example, it can be used in an amount of 30 parts by weight or less with respect to 100 parts by weight of the polyisobutylene.

(5) Other additives

An organic solvent may be added as a diluent to the rubber-based adhesive composition. The diluent is not particularly limited, and examples include toluene, xylene, n-heptane, and dimethyl ether. These diluents can be used individually or in combination of two or more. Among these, toluene is preferable.

The amount of diluent added is not particularly limited, but is preferably added in an amount of about 50 to 95% by weight, and more preferably about 70 to 90% by weight, in the rubber-based adhesive composition. It is preferable that the amount of diluent added is within the above range from the viewpoint of applicability to a support, etc.

Additives other than the above may be added to the rubber-based adhesive composition of the present invention, within a range that does not impair the effect of the present invention. Specific examples of additives include softeners, crosslinking agents (eg, polyisocyanates, epoxy compounds, alkyl etherified melamine compounds, etc.), fillers, anti-aging agents, ultraviolet absorbers, and the like. The type, combination, addition amount, etc. of additives added to the rubber-based adhesive composition can be appropriately set depending on the purpose. The content (total amount) of the above additives in the rubber-based adhesive composition is preferably 30% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less.

2. Rubber-based adhesive layer

The rubber-based adhesive layer of the present invention is characterized by being formed from the above-described rubber-based adhesive composition. The method for producing the rubber-based adhesive layer of the present invention will be described later.

The thickness of the rubber-based adhesive layer of the present invention is not particularly limited and can be appropriately set depending on the application, but is preferably 250 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less. The lower limit of the thickness of the adhesive layer is not particularly limited, but from the viewpoint of durability, it is preferably 1 μm or more, and more preferably 5 μm or more.

The moisture permeability of the rubber-based adhesive layer of the present invention is not particularly limited, but is preferably 50 g/(m2·day) or less, more preferably 30 g/(m2·day) or less, and 20 g/(m2·day) or less. It is more preferable, and 15 g/(m2·day) or less is particularly preferable. In addition, the lower limit of the moisture permeability is not particularly limited, but ideally, it is desirable not to transmit water vapor at all (i.e., 0 g/(m 2 ·day)). If the moisture permeability of the rubber-based adhesive layer is within the above range, when the adhesive layer is applied to an optical film such as a polarizing film, transfer of moisture into the optical film can be suppressed, and deterioration of the optical film due to moisture can be suppressed. It is desirable because it exists. The water vapor transmission rate is 40°C and 92%R.H. at a thickness of 50 μm of the rubber-based adhesive layer. It is a water vapor transmission rate (water vapor transmission rate) under conditions, and the measurement method can be measured by the method described in the Examples.

In addition, the gel fraction of the adhesive layer of the present invention is not particularly limited, but is preferably about 10 to 98%, more preferably about 25 to 98%, even more preferably about 45 to 90%, and 60 to 85%. It is particularly preferable that it is about %. It is preferable that the gel fraction is within the above range because both durability and adhesiveness can be achieved. In addition, the gel fraction can be measured by the method described in the Examples.

3. Method of manufacturing rubber-based adhesive layer

The method for producing a rubber-based adhesive layer of the present invention is characterized by including a step of crosslinking the polyisobutylene by irradiating the rubber-based adhesive composition with active energy rays.

Irradiation of the above-mentioned active energy rays is usually applied to the application layer obtained by applying the above-mentioned rubber-based adhesive composition to various supports, etc. In addition, the active energy ray may be irradiated directly to the application layer (without bonding other members, etc.), or may be irradiated after bonding various members such as optical films such as separators and glass to the application layer. In the case of irradiation after bonding to the optical film or various members, active energy rays may be irradiated beyond the optical film or various members, or the optical film or various members may be peeled and active energy rays may be irradiated from the peeled surface. It's okay too.

As a method of applying the rubber-based adhesive composition, various methods are used. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Methods such as an extrusion coating method can be mentioned.

In the production method of the present invention, the application layer of the rubber-based adhesive composition is irradiated with active energy rays. However, when the rubber-based adhesive composition contains an organic solvent as a diluent, heating is performed after application and before irradiation with active energy rays. It is preferable to remove the solvent, etc. by drying or the like.

The heat drying temperature is not particularly limited, but is preferably about 30°C to 90°C, and more preferably about 60°C to 80°C from the viewpoint of reducing the residual solvent. As for the drying time, an appropriate appropriate time may be adopted. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

Examples of the active energy rays include visible rays, ultraviolet rays, and electron beams. Among these, ultraviolet rays are preferable.

The irradiation conditions of ultraviolet rays are not particularly limited and can be set to any appropriate conditions depending on the composition of the rubber-based adhesive composition to be crosslinked. For example, the cumulative amount of irradiation is preferably 100 mJ/cm2 to 2000 mJ/cm2.

As the support, for example, a peeled sheet (separator) can be used.

As constituent materials of the separator, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foil, and laminates thereof, etc. Suitable thin films, etc. can be mentioned, but plastic films are suitably used because they have excellent surface smoothness.

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, and polybutylene terephthalate film. , polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be subjected to mold release and antifouling treatment using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., or antistatic treatment such as coating type, encapsulation type, or vapor deposition type. . In particular, by appropriately performing a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator, the peelability from the adhesive layer can be further improved.

The thickness and moisture permeability of the rubber-based adhesive layer obtained by the production method of the present invention are as described above.

4. Optical film with adhesive layer

The optical film with a rubber-based adhesive layer of the present invention is characterized by having an optical film and the rubber-based adhesive layer provided on the optical film.

As a method of forming a rubber-based adhesive layer on the optical film, the rubber-based adhesive layer can be formed on the optical film by applying the rubber-based adhesive composition on the optical film and irradiating it with active energy rays. Additionally, as described above, a rubber-based adhesive layer can be formed on a support, etc., and the rubber-based adhesive layer is transferred onto an optical film to form an optical film having a rubber-based adhesive layer. In this case, the peeled sheet used in the production of the optical film with the rubber-based adhesive layer can be used as is as a separator for the optical film with the rubber-based adhesive layer, resulting in simplification in the process.

As the optical film, those used in forming various image display devices such as liquid crystal display devices are used, and the type is not particularly limited. For example, a polarizing film can be mentioned as an optical film. A polarizing film having a protective film on one or both sides of the polarizer is generally used, but in the present invention, it is preferable that it is a one-sided protective polarizing film from the viewpoint of thickness reduction.

The polarizer is not particularly limited and various types can be used. As a polarizer, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film, and 1 Examples include axially stretched polyene-based oriented films, such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride films. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and stretching it uniaxially can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine, dyeing it, and stretching it to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution such as potassium iodide, which may contain boric acid, zinc sulfate, zinc chloride, etc. Additionally, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol-based film with water to remove contamination and anti-blocking agents from the surface of the polyvinyl alcohol-based film, swelling the polyvinyl alcohol-based film also has the effect of preventing uneven dyeing and other unevenness. Stretching may be performed after dyeing with iodine, may be carried out while dyeing, or may be carried out after stretching and then dyed with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Additionally, from the viewpoint of thinning, it is preferable to use a thin polarizer with a thickness of 10 μm or less. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer has little thickness unevenness, is excellent in visibility, and has excellent durability due to little dimensional change, and furthermore, it is desirable that the thickness of the polarizing film can be reduced.

As a thin polarizer, representative examples include Japanese Patent Application Laid-Open No. 51-069644, Japanese Patent Application Publication No. 2000-338329, Pamphlet International Publication No. 2010/100917, or Japanese Patent Application Publication No. 2014-59328. A thin polarizing film described in Japanese Patent Application Laid-Open No. 2012-73563 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a resin substrate for stretching in the state of a laminate, and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it becomes possible to stretch without problems such as breakage during stretching because it is supported by the resin substrate for stretching.

As the thin polarizing film, it can be stretched at a high magnification and improve polarization performance among manufacturing methods including a stretching step and a dyeing step in the laminate state. Accordingly, International Publication No. 2010/100917 pamphlet, or It is preferably obtained by a manufacturing method including a step of stretching in an aqueous solution of boric acid as described in Japanese Patent Application Laid-Open No. 2014-059328 or Japanese Patent Application Publication No. 2012-073563. It is preferably obtained by a manufacturing method described in Patent Publication No. 2012-073563 that includes a step of auxiliary stretching in air before stretching in an aqueous solution of boric acid.

The material forming the protective film provided on one or both sides of the polarizer is preferably one having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetylcellulose and triacetylcellulose, acrylic polymers such as polymethyl methacrylate, polystyrene and acrylonitrile-styrene copolymers. Styrene-based polymers such as (AS resin) and polycarbonate-based polymers can be mentioned. In addition, polyolefin-based polymers such as polyethylene, polypropylene, polyolefins with cyclo or norbornene structures, ethylene-propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, and alcohol. Phone-based polymer, polyether sulfone-based polymer, polyether ether ketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, Epoxy-based polymers or blends of these polymers can also be cited as examples of polymers that form the protective film. The protective film can also be formed as a thermosetting type or ultraviolet curing type resin layer such as acrylic, urethane, acrylic urethane, epoxy, silicone, etc. When providing protective films on both sides of the polarizer, protective films made of the same polymer material may be used on the front and back, or protective films made of different polymer materials, etc. may be used.

The thickness of the protective film can be determined as appropriate, but is generally about 1 to 500 ㎛ based on factors such as strength, workability such as handleability, and thinness.

The polarizer and the protective film are usually in close contact through a water-based adhesive or the like. Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl latex-based adhesives, water-based polyurethane, and water-based polyester. In addition to the above, examples of adhesives between the polarizer and the protective film include ultraviolet curing adhesives and electron beam curing adhesives. The adhesive for electron beam curable polarizing film exhibits suitable adhesiveness to the various protective films mentioned above. Additionally, the adhesive used in the present invention may contain a metal compound filler.

The surface of the protective film to which the polarizer is not attached may be treated with a hard coat layer, anti-reflection treatment, anti-sticking, diffusion or anti-glare treatment.

For example, as shown in FIG. 1, when the polarizing film 2 is a single-sided protective polarizing film having the protective film 5 only on one side of the polarizer 4, the adhesive layer 3 is provided with the polarizer ( It is preferable that it is formed on the side that does not have the protective film 5 (that is, the polarizer 4 side) of 4). In this case, the polarizer 4 and the adhesive layer 3 do not necessarily need to be in contact, but it is preferable that they are in contact from the viewpoint of significantly exhibiting the effects of the present invention. By having such a structure, transfer of moisture, etc. to the polarizer can be suppressed, and deterioration of the polarizer of the single-sided protective polarizing film can be suppressed.

In addition, optical films other than the above polarizing plate films include, for example, reflectors, transflective plates, retardation plates (including 1/2 or 1/4 wave plates), visual compensation films, and liquid crystal display films such as brightness enhancement films. Examples include optical layers that may be used in the formation of devices, etc. Among these, a brightness improving film can be suitably used as an optical film. In addition to being able to be used alone as an optical film, these can be laminated on the polarizing film for practical use and used as one layer or two or more layers.

Additionally, the adhesive layer can be formed on the surface of the optical film or polarizer after forming an anchor layer or a transparent resin layer or performing various adhesion facilitation treatments such as corona treatment or plasma treatment. Additionally, adhesion facilitation treatment may be performed on the surface of the adhesive layer.

5. Optical members

The optical member of the present invention is an optical member (hereinafter referred to as a “first optical member”) comprising an optical film having the adhesive layer and a brightness improving film, or the adhesive layer and the optical film at 40° C. and 92% R.H. An optical member (hereinafter referred to as a “second optical member”) containing a film having a moisture permeability of 1 g/(m 2 ·day) or less can be mentioned.

The first optical member further laminates the brightness improving film through the adhesive layer of the optical film having the adhesive layer. The optical film having an adhesive layer in the first optical member is preferably a polarizing film having an adhesive layer. For example, as shown in FIG. 2, an optical member 10 having a polarizing film 2, an adhesive layer 3, and a brightness enhancing film 6 can be mentioned. In addition, this optical member 10 may have other layers. For example, as shown in FIG. 3, an adhesive layer is provided on the side of the brightness improving film 6 that does not have the adhesive layer 3. The prism sheets 7 can be further laminated through (not shown) or the like. The prism sheet 7 typically has a substrate and a prism portion. Additionally, in FIGS. 2 and 3, a single-sided protective polarizing film is described as in FIG. 1, but a double-sided protective polarizing film may also be used. It is preferable to use such an optical member as a polarizing plate on the backlight side of a liquid crystal display device.

Additionally, examples of the brightness improving film 6 include reflective polarizing plates. The above-mentioned sandpaper polarizer is a linearly polarized light separation type polarizer. Representative examples include a grid-type polarizer, a multilayer thin film laminate polarizer made of two or more types of materials with different refractive indices, a vapor-deposited multilayer thin film with different refractive indices, a birefringent layer multilayer thin film laminate made of two or more types of materials with different refractive indices, and a multilayer thin film laminate of two or more types with different refractive indices. Examples include a stretched product of two or more types of resin laminates, and a polarizing plate that separates linearly polarized light by reflecting/transmitting it in an orthogonal axial direction (linearly polarized light separation type reflective polarizing plate). Among these, a linearly polarized separation type reflective polarizer is suitably used. As such a reflective polarizing plate, for example, those commercially available under the brand name "D-BEF" manufactured by 3M or "Nipox APCF" manufactured by Nitto Denko Co., Ltd. can also be used.

In addition, examples of films used in the second optical member having a moisture permeability of 1 g/m2·day or less at 40°C and 92%R.H. include barrier layers used in organic EL devices. Barrier layers used in organic EL devices include, for example, trifluoroethylene, polytrifluoroethylene chloroethylene (PCTFE), polyimide, polycarbonate, polyethylene terephthalate, alicyclic polyolefin, and ethylene-vinyl alcohol copolymer. Examples include a polymer layer or a laminate thereof, and a polymer layer coated with an inorganic thin film such as silicon oxide, silicon nitride, aluminum oxide, or diamond-like carbon using a film forming method such as sputtering. An optical member having such a low moisture permeability film can be suitably used in an organic EL device and, specifically, can be used as a sealing member for an organic EL element.

6. Image display device

The image display device of the present invention is characterized by comprising at least one member selected from the group consisting of the polarizing film having the pressure-sensitive adhesive layer and the optical member. Examples of image display devices include liquid crystal display devices and organic EL display devices.

The image display device of the present invention may include an optical film or an optical member having an adhesive layer of the present invention, and other structures may be similar to those of a conventional image display device.

Since the image display device of the present invention includes an optical film or optical member having the adhesive layer, it has high optical reliability.

Example

Below, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, parts and percentages in each example are all based on weight.

Production Example 1 (Production of Polarizing Film (1))

In order to manufacture a thin polarizing film, a 9㎛ thick polyvinyl alcohol (PVA) layer was first formed on an amorphous polyethylene terephthalate (PET) substrate by aerial auxiliary stretching at a stretching temperature of 130°C to produce a stretched laminate. did. Next, the stretched laminate is dyed to produce a colored laminate, and the colored laminate is stretched in boric acid water at a stretching temperature of 65°C to obtain a total stretching ratio of 5.94 times to a 4㎛ thickness that is integrally stretched with the amorphous PET base material. An optical film laminate containing a PVA layer was produced. Through this two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate are highly oriented, and the iodine adsorbed by dyeing forms a highly functional polarizing film (polarizer) oriented in one direction as a polyiodine ion complex. An optical film laminate containing a PVA layer with a thickness of 5 μm was produced.

A protective film (20 μm thick) was applied to the surface of the polarizing film (polarizer, thickness: 5 μm) of the optical film laminate relative to the polarizer so that the thickness of the adhesive layer was 0.1 μm. A (meth)acrylic resin film having a ton ring structure subjected to corona treatment) was bonded, and then dried at 50°C for 5 minutes. Next, the amorphous PET substrate was peeled, and a piece protective polarizing film (polarizing film (1)) using a thin polarizer was produced.

Production Example 2 (Production of Polarizing Film (2))

A polyvinyl alcohol film with a thickness of 30 μm was stretched up to 3 times while dyeing for 1 minute in an iodine solution with a concentration of 0.3% at 30°C between rolls with different speed ratios. After that, it was stretched to a total stretching ratio of 6 while immersed in an aqueous solution containing 4% concentration of boric acid and 10% concentration of potassium iodide at 60°C for 0.5 minutes. Next, it was washed by immersing it in an aqueous solution containing 1.5% potassium iodide at 30°C for 10 seconds, and then dried at 50°C for 4 minutes to obtain a polarizer with a thickness of 12 μm. On one side of the polarizer, a saponified triacetylcellulose film with a thickness of 25 μm and hard coded on one side was placed, and on the other side of the polarizer, a cycloolefin-based resin film with a thickness of 13 μm was placed on a polyvinyl alcohol-based film. They were bonded together with an adhesive (thickness of adhesive layer: 0.1 μm) to produce a positive protective polarizing film (polarizing film (2)). The structure of the polarizing film 2 was hard coat/triacetylcellulose film/adhesive layer/polarizer/adhesive layer/cycloolefin-based resin film.

Production Example 3 (Production of Polarizing Film (3))

In a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction pipe, as monomer components, 99 parts by weight of butylacrylate (BA), 1 part by weight of 4-hydroxybutylacrylate (4HBA), and a polymerization initiator. As a result, 0.2 parts by weight of azobisisobutyronitrile and ethyl acetate as a polymerization solvent were added so that the solid content was 20%, then nitrogen gas was introduced and nitrogen substitution was performed for about 1 hour while stirring. After that, the flask was heated at 60°C and reacted for 7 hours to obtain an acrylic polymer with a weight average molecular weight (Mw) of 1.1 million. To the above acrylic polymer solution (solid content: 100 parts by weight), 0.8 parts by weight of trimethylolpropantolylene diisocyanate (product name: Coronate L, manufactured by Nippon Polyurethane Kogyo Co., Ltd.) as an isocyanate-based crosslinking agent, and a silane coupling agent (product name: KBM- 0.1 part by weight of 403 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to prepare an acrylic adhesive composition (A).

The obtained pressure-sensitive adhesive composition (solution) was applied to the peeled surface of a 38-μm-thick polyester film (product name: Diafoil MRF, manufactured by Mitsubishi Juushi Co., Ltd.), one side of which had been peeled off with silicone, to form an application layer. Next, the application layer was dried at 155°C for 3 minutes to form an acrylic adhesive layer (A) with a thickness of 20 μm, and an adhesive sheet made of polyester film/acrylic adhesive layer (A) was produced.

The adhesive layer of the adhesive sheet was bonded to the protective film of the polarizing film 1 obtained in Production Example 1 (a (meth)acrylic resin film having a lactone ring structure with a thickness of 20 μm subjected to corona treatment), and the polyester A polarizing film (3) consisting of a film (separator)/acrylic adhesive layer (A)/protective film/adhesive layer/polarizer was obtained.

Example 1

(Preparation of rubber-based composition)

100 parts by weight of polyisobutylene (brand name: OPPANOL B80, Mw: about 750,000, manufactured by BASF) and tricyclodecane dimethanol diacrylate as a polyfunctional radically polymerizable compound (brand name: NK Ester A-DCP, 2 A toluene solution (adhesive solution) containing 5 parts by weight of functional acrylate, molecular weight: 304, manufactured by Shinnakamura Chemical Industries, Ltd., and 0.5 parts of benzophenone, a hydrogen extraction type photopolymerization initiator (manufactured by Wako Pure Chemical Industries, Ltd.). was adjusted so that the solid content was 15% by weight, and a rubber-based adhesive composition (solution) was prepared.

(Formation of rubber-based adhesive sheet)

The obtained rubber-based pressure-sensitive adhesive composition (solution) was applied to the peeled surface of a 38-μm-thick polyester film (product name: Diafoil MRF, manufactured by Mitsubishi Juushi Co., Ltd.), one side of which had been peeled off with silicone, to form an application layer. Next, the application layer was dried at 80°C for 3 minutes to form a rubber-based adhesive layer, and an adhesive sheet with a thickness of the rubber-based adhesive layer of 50 μm was produced. In addition, on the adhesive surface of the adhesive sheet, a polyester film with a thickness of 38 ㎛ (product name: Diafoil MRF, manufactured by Mitsubishi Juicy Co., Ltd.) whose one side was peeled with silicone was applied, and the peeled surface and the rubber-based adhesive layer were applied. joined to fit. The polyester film coated on both sides of the rubber-based adhesive layer functions as a release liner (separator).

One separator was peeled off, and the side from which the separator was peeled was irradiated with ultraviolet rays at room temperature to obtain a rubber-based adhesive sheet consisting of a rubber-based adhesive layer/separator. The ultraviolet irradiation was in the UVA region and the amount of light was 1000 mJ/cm2.

Examples 2 to 22, Comparative Examples 1 to 3, 5

A rubber-based adhesive sheet was produced in the same manner as in Example 1 except for the composition and film thickness shown in Table 1.

Comparative Example 4

(Production of acrylic adhesive sheet)

The acrylic adhesive composition (A) prepared in Preparation Example 3 was applied to the peeled surface of a 38 ㎛ thick polyester film (product name: Diafoil MRF, manufactured by Mitsubishi Juushi Co., Ltd.), one side of which was peeled with silicone. formed a layer. Next, the application layer was dried at 120°C for 3 minutes to form an adhesive layer, and an adhesive sheet with an adhesive layer thickness of 50 μm was produced. Additionally, on the adhesive side of the adhesive sheet, a polyester film with a thickness of 38 μm (product name: Diafoil MRF, manufactured by Mitsubishi Juushi Co., Ltd.), which has been peeled on one side with silicone, is placed so that the peeled surface and the adhesive layer are in contact with each other. By bonding, an acrylic adhesive sheet was obtained. The polyester film coated on both sides of the adhesive layer functions as a release liner (separator).

The following evaluation was performed on the adhesive composition and adhesive sheet obtained in the Examples and Comparative Examples. The evaluation results are shown in Table 1.

<Durability 1 (polarizing film (1))>

The polarizing film 1 obtained in Production Example 1 and the adhesive sheets obtained in Examples and Comparative Examples were laminated so that the polarizer of the polarizing film 1 and the adhesive layer of the adhesive sheet were in contact, respectively, to produce a polarizing film with an adhesive layer. got it The release liner of the adhesive layer was left as a separator. The structure of the obtained polarizing film with an adhesive layer was protective film/adhesive layer/polarizer/adhesive layer/separator.

The separator of the obtained polarizing film with the adhesive layer was peeled off, the test piece was bonded to a glass plate, and the state after immersion for 500 hours in an environment at 95°C was observed with the naked eye or using a magnifying glass (20x). It was evaluated according to the following evaluation criteria.

◎: Even when checked with a magnifying glass, no problems (foaming, peeling, etc.) occurred.

○: The problem could not be confirmed with the naked eye, but when checked with a magnifying glass, a slight problem occurred that did not cause any problem in use.

×: The problem could be confirmed with the naked eye.

<Durability 2 (Polarizing Film (2))>

The polarizing film 2 obtained in Production Example 2 and the adhesive sheets obtained in Examples and Comparative Examples were laminated so that the cycloolefin-based resin film of the polarizing film 2 and the adhesive layer of the adhesive sheet were in contact, respectively, to form an adhesive layer. A polarizing film was obtained. The release liner of the adhesive layer was left as a separator. The structure of the obtained polarizing film with an adhesive layer was hard coat/triacetylcellulose film/adhesive layer/polarizer/adhesive layer/cycloolefin resin film/adhesive layer/separator.

The separator of the obtained polarizing film with the adhesive layer was peeled off, the test piece was bonded to a glass plate, and the state after immersion for 500 hours in an environment at 95°C was observed with the naked eye or using a magnifying glass (20x). <Durability 1> was evaluated according to the same evaluation criteria as the test.

<Durability 3 (polarizing film (3))>

A luminance-enhancing film with an adhesive layer was produced by bonding the adhesive layer of the adhesive sheet obtained in the examples and comparative examples with a 20 μm linearly polarized light separation film (product name: D-BEF, manufactured by 3M).

The brightness improving film having the adhesive layer and the polarizing film 3 obtained in Production Example 3 are laminated so that the adhesive layer of the brightness improving film having the adhesive layer and the polarizer of the polarizing film 3 obtained in Production Example 3 are in contact with each other. A polarizing film with an adhesive layer was obtained. The release liner of the adhesive layer was left as a separator. The structure of the obtained polarizing film with an adhesive layer was polyester film (separator)/acrylic adhesive layer (A)/protective film/adhesive layer/polarizer/adhesive layer obtained in Examples and Comparative Examples/brightness improvement film.

The separator of the obtained polarizing film with the adhesive layer was peeled off, the test piece was bonded to a glass plate, and the state after immersion for 500 hours in an environment at 95°C was observed with the naked eye or using a magnifying glass (20x). <Durability 1> was evaluated according to the same evaluation criteria as the test.

In the above <Durability 1> and <Durability 2> tests, the polarizing film was laminated on the adherend (glass plate) of the durability test, respectively, through the adhesive layer obtained in the examples and comparative examples, but in the above <Durability 3> In the test, the adherend (glass plate) for the durability test and the polarizing film were laminated through the acrylic adhesive layer (A) obtained in Production Example 3.

<Gel fraction>

The total weight of the smoke chamber and a porous membrane made of tetrafluoroethylene resin with a pore diameter of 0.2 μm (product name: Nitoflon NTF1122, manufactured by Nitto Denko Co., Ltd.) was previously measured (W _a (mg)). From the obtained adhesive sheet, about 1 g of the adhesive layer was collected, wrapped around the porous membrane in a drawstring shape, and the entrance was tied with a string, and then the weight of the bundle was measured (W _b (mg)). This bundle was placed in a screw bottle with a capacity of 50 mL, and the screw bottle was filled with toluene. After leaving this at room temperature for 7 days, the bundle was taken out and dried at 130°C for 2 hours, the weight of the bundle was measured (W _c (mg)), and the gel fraction was calculated using the following equation.

Gel fraction (%)=(W _c -W _a )/(W _b -W _a )×100

<Water permeability>

Using the adhesive compositions obtained in the examples and comparative examples, a pressure-sensitive adhesive sheet with an adhesive layer thickness of 50 μm was formed according to the method described in the examples. The release liner on one side of the adhesive sheet was peeled off to expose the adhesive surface, and the adhesive sheet was bonded to a triacetylcellulose film (TAC film, thickness: 25 μm, manufactured by Konica Minolta Co., Ltd.) using the adhesive surface. Then, the other release liner was peeled off to obtain a sample for measurement.

Next, using this sample for measurement, the moisture permeability (water vapor transmission rate) was measured by a moisture permeability test method (cup method, based on JIS Z 0208) under the following conditions.

Measurement temperature: 40℃

Relative Humidity: 92%

Measurement time: 24 hours

Additionally, a constant temperature and humidity chamber was used during the measurement.

The notation in Table 1 is as follows.

<Polyisobutylene>

OPPANOL B80: Polyisobutylene (Mw: approx. 750,000, manufactured by BASF)

OPPANOL B100: Polyisobutylene (Mw: approx. 1.68 million, manufactured by BASF)

<Other polymers>

Acrylic resin: Acrylic adhesive composition obtained in Comparative Example 4

<Tackifier>

Fully hydrogenated terpene phenol (A): Fully hydrogenated terpene phenol with a softening point of 135°C and a hydroxyl value of 160.

Fully hydrogenated terpene phenol (B): Fully hydrogenated terpene phenol with a softening point of 160°C and a hydroxyl value of 60.

<Multifunctional radically polymerizable compound>

A-DCP: Tricyclodecane dimethanol diacrylate (brand name: NK ester A-DCP, difunctional acrylate, molecular weight: 304, manufactured by Shinnakamura Chemical Industry Co., Ltd.)

DCP: Tricyclodecane dimethanol dimethacrylate (brand name: NK ester DCP, difunctional methacrylate, molecular weight: 332, manufactured by Shinnakamura Chemical Industry Co., Ltd.)

A-TMPTA: Trimethylolpropane triacrylate (brand name: NK ester A-TMPT, trifunctional acrylate, molecular weight: 296, manufactured by Shinnakamura Chemical Industry Co., Ltd.)

<Photopolymerization initiator>

Benzophenone: Hydrogen abstraction type photopolymerization initiator

Irgacure 184: Cleavage type photoinitiator, 1-hydroxycyclohexylphenylketone (manufactured by BASF)

1: Polarizing film with adhesive layer
2: Polarizing film
3: Adhesive layer
4: Polarizer
5: Protective film
6: Brightness enhancement film
7: Prism sheet
10: optical member

Claims (18)

It is a rubber-based adhesive composition containing polyisobutylene, a hydrogen abstraction type photopolymerization initiator, and a polyfunctional radical polymerizable compound,
A rubber-based adhesive composition, wherein the 50 μm thick rubber-based adhesive layer formed from the rubber-based adhesive composition has a moisture permeability at 40°C and 92%RH of 20 g/(m2·day) or less. The rubber-based adhesive composition according to claim 1, wherein the polyfunctional radically polymerizable compound is contained in an amount of 20 parts by weight or less based on 100 parts by weight of the polyisobutylene. The rubber-based adhesive composition according to claim 2, wherein the polyfunctional radically polymerizable compound is a compound having at least two (meth)acryloyl groups. The method according to claim 3, wherein the compound having at least two (meth)acryloyl groups is a bifunctional (meth)acrylate having two (meth)acryloyl groups and/or three (meth)acryloyl groups. A rubber-based adhesive composition characterized in that it is a trifunctional (meth)acrylate having. The rubber-based adhesive composition according to any one of claims 1 to 4, wherein the hydrogen abstraction type photopolymerization initiator is a benzophenone-based compound. The rubber-based adhesive composition according to any one of claims 1 to 4, wherein the content of the hydrogen abstraction type photopolymerization initiator is 0.001 to 10 parts by weight based on 100 parts by weight of the polyisobutylene. The tackifier according to any one of claims 1 to 4, wherein at least one type of tackifier selected from the group consisting of a tackifier containing a terpene skeleton, a tackifier containing a rosin skeleton, and hydrogenated substances thereof. A rubber-based adhesive composition comprising: The rubber-based adhesive composition according to any one of claims 1 to 4, which is crosslinked by irradiation of active energy rays. The rubber-based adhesive composition according to claim 8, wherein the active energy ray is ultraviolet ray. A rubber-based adhesive layer formed from the rubber-based adhesive composition according to claim 1. An optical film with a rubber-based adhesive layer, comprising an optical film and the rubber-based adhesive layer according to claim 10 provided on the optical film. The optical film with an adhesive layer according to claim 11, wherein the optical film is a polarizing film having a protective film on at least one side of the polarizer. The rubber-based adhesive layer according to claim 12, wherein the polarizing film is a single-sided protective polarizing film having a protective film on only one side of the polarizer, and the rubber-based adhesive layer is laminated on the side of the polarizer that does not have a protective film. An optical film having a. The optical film with a rubber-based adhesive layer according to claim 11, wherein the optical film is a brightness enhancing film. An optical member comprising the rubber-based adhesive layer according to claim 10 and a film having a moisture permeability of 1 g/(m2·day) or less at 40°C and 92%R.H. An image display device comprising at least one member selected from the group consisting of an optical film having a rubber-based adhesive layer according to claim 11 and an optical member according to claim 15. A method for producing a rubber-based adhesive layer, comprising the step of crosslinking the polyisobutylene by irradiating active energy rays to the rubber-based adhesive composition according to any one of claims 1 to 4. delete

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