WO2020122148A1

WO2020122148A1 - Polarizing film with adhesive layer

Info

Publication number: WO2020122148A1
Application number: PCT/JP2019/048565
Authority: WO
Inventors: 有森本; 雄祐外山; 武史仲野
Original assignee: 日東電工株式会社
Priority date: 2018-12-14
Filing date: 2019-12-11
Publication date: 2020-06-18
Also published as: TW202037695A; TW202033713A; KR20210102186A; WO2020122147A1; KR20210102185A; TWI827766B; CN117518328A; CN113196117A; WO2020122146A1; TWI825244B; CN113167964B; CN113242987B; TWI827765B; CN113196117B; CN113242987A; CN113167964A; TW202031852A; KR20210102187A

Abstract

Provided is a thin polarizing film with an adhesive layer which has high durability and reworkability, the polarizing film having excellent adhesion (anchoring) to an adhesive. Provided is a polarizing film with an adhesive layer comprising: a polarizing film provided with a polarizer and a protective film disposed on the visible side of the polarizer; and an adhesive layer disposed on the opposite side of the polarizer from the visible side. The adhesive layer contains a base polymer and a silicone oligomer Ps. The silicone oligomer Ps is contained in an amount of 0.1 to 20 parts by weight relative to 100 parts by weight of the base polymer. The silicone oligomer Ps has a Tg of -50°C to 100°C, a side-chain silicone functional group equivalent of 1000 to 20000 g/mol and a weight average molecular weight of 10000 to 300000.

Description

Polarizing film with adhesive layer

The present invention relates to a polarizing film with an adhesive layer. More specifically, the present invention relates to a pressure-sensitive adhesive layer-attached thin polarizing film having a protective film on one side of a polarizer.

According to the image forming method, it is essential for liquid crystal display devices to place polarizing films on both sides of the glass substrate that forms the surface of the liquid crystal panel. As the polarizing film, generally, a polyvinyl alcohol-based film and a polarizer made of a dichroic material such as iodine having a protective film bonded to one or both surfaces thereof with a polyvinyl alcohol-based adhesive or the like are used. ..

When attaching the polarizing film to a liquid crystal cell etc., an adhesive is usually used. In addition, the pressure-sensitive adhesive is preliminarily provided as a pressure-sensitive adhesive layer on one surface of the polarizing film, since it has advantages such as being able to instantly fix the polarizing film and not requiring a drying step to fix the polarizing film. .. That is, a polarizing film with an adhesive layer is generally used for sticking a polarizing film (Patent Documents 1 and 2).

Further, when a polarizing film or a polarizing film with a pressure-sensitive adhesive layer is attached to a glass substrate of a liquid crystal panel, durability is required, and for example, in a durability test such as heating and humidification that is usually performed as an environmental promotion test, adhesion It is required that problems such as peeling and floating due to the agent layer do not occur.

As described above, while the pressure-sensitive adhesive used for the polarizing film is required to have high durability, there is an increasing demand for reworkability in order to recover a defect or a bonding error caused by a process defect in bonding the polarizing plate. .. In recent years, a polarizing plate having a thin polarizer and a protective film on only one side of the polarizer has been widely used. Such a thin polarizing plate has a small dimensional change after heating and a high likelihood of durability, but on the other hand, since the layer thickness of the polarizing film is thin, it easily breaks during rework and the rework hurdle increases. The fact is that Reworkability is an important item, but high durability and reworkability are in a trade-off relationship, and it is a very difficult property to be compatible with each other.

Furthermore, if the adhesion between the polarizing film and the adhesive layer is poor, there will be defects in which only the adhesive remains on the panel during rework. In addition, adhesiveness (anchoring force) between the polarizing film and the adhesive is important because adhesive cracks may occur when punching the rolled polarizing film, which may affect visibility. It is a characteristic.

Further, since the thin polarizing plate as described above has the protective film on only one side of the polarizer, according to the conventional method, the conductive coating layer (anchor coat layer) is directly attached to the polarizer, that is, the protective film. It will be applied without going through. However, the thin polarizing plate is weak against external stress. Further, there is a problem in that iodine is easily decolorized in the polarizer when it is directly applied to the polarizer without a protective film. Therefore, the conductive coating layer (anchor coat layer) cannot be directly provided on the polarizer by using the conventional method.

Japanese Patent Laid-Open No. 2011-219765 JP-A-2018-169612

In view of the above background art, with a pressure-sensitive adhesive layer, it is possible to provide both high durability and reworkability that are in a trade-off relationship, and excellent in adhesion (anchoring force) between the polarizing film and the pressure-sensitive adhesive. A thin polarizing film is strongly desired.

As a result of intensive studies, the present inventors have found that the polarizing film with an adhesive layer of the present invention can solve the above problems, and have completed the present invention.

That is, the present invention includes the following embodiments.

(1) A polarizing film comprising a polarizer and a protective film provided on the viewing side of the polarizer,
A polarizing film with a pressure-sensitive adhesive layer, comprising a pressure-sensitive adhesive layer provided on the side opposite to the viewing side of the polarizer,
The pressure-sensitive adhesive layer includes a base polymer and a silicone oligomer Ps,
The silicone oligomer Ps is included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the base polymer,
The silicone oligomer Ps has a Tg of −50° C. or higher and 100° C. or lower, a side chain silicone functional group equivalent of 1000 to 20000 g/mol, and a weight average molecular weight of 10,000 to 300,000. the film.

(2) The pressure-sensitive adhesive according to (1) above, wherein the silicone oligomer Ps contains, as monomer units, a monomer having a polyorganosiloxane skeleton and a homopolymer having a glass transition temperature of −70° C. or higher and 180° C. or lower. Polarized film with layers.

(3) The base polymer contains, as a monomer unit, 80% by weight or more of an alkyl (meth)acrylate (A) whose homopolymer has a glass transition temperature of −80° C. or higher and 0° C. or lower, (1) or The polarizing film with an adhesive layer according to (2).

(4) The base polymer further contains, as a monomer unit, at least one polar monomer (B) selected from the group consisting of a carboxyl group-containing monomer (b1) and a nitrogen-containing monomer (b2) in an amount of 5% by weight or less. The polarizing film with a pressure-sensitive adhesive layer according to (3) above, characterized in that

(5) The base polymer comprises, as monomer units, an alkyl methacrylate having a glass transition temperature of a homopolymer of 0° C. to 180° C. in an amount of 0.1 to 18% by weight and a hydroxyl group-containing monomer in an amount of 0 to 5% by weight. The pressure-sensitive adhesive layer-attached polarizing film as described in (4) above, further comprising:

(6) The polarizing film with a pressure-sensitive adhesive layer according to any one of (1) to (5) above, wherein the base polymer has a weight average molecular weight of 500,000 to 2,500,000.

(7) The polarizing film with an adhesive layer according to any one of (1) to (6) above, wherein the thickness of the polarizer is more than 0 μm and 12 μm or less.

(8) The polarizing film with a pressure-sensitive adhesive layer according to any one of (1) to (7) above, wherein the melting temperature of the silicone oligomer Ps is −20° C. to 120° C.

ADVANTAGE OF THE INVENTION According to this invention, while giving the reworkability immediately after bonding, the adhesive force can increase after heating and durability can be given, and the adhesiveness (anchoring force) between a polarizing film and an adhesive is excellent. A thin polarizing film with an adhesive layer can be provided.

FIG. 1 is an example of a schematic sectional view of a thin polarizing film with an adhesive layer of the present invention.

A preferred embodiment of the present invention will be described below. Matters other than the matters particularly referred to in the present specification and necessary for the implementation of the present invention should be determined based on the teaching about the implementation of the invention described in the present specification and the common general knowledge as of the filing. It can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and the common general technical knowledge in the field.

<Polarizing film with adhesive layer>
The polarizing film with a pressure-sensitive adhesive layer of the present invention includes a polarizing film and a pressure-sensitive adhesive layer. In the present invention, the pressure-sensitive adhesive layer may be present on one side or both sides of the polarizing film.

The structure of a polarizing film with an adhesive layer according to one embodiment is schematically shown in FIG. The pressure-sensitive adhesive layer-attached polarizing film 100 is configured as a pressure-sensitive adhesive layer-attached polarizing film including a polarizing film 13 and an adhesive layer 14 provided on one surface thereof. In FIG. 1, the polarizing film 13 is composed of a polarizer 11 and a protective film 12 provided on the viewing side of the polarizer 11. The pressure-sensitive adhesive layer 14 is provided on the side opposite to the viewing side of the polarizer 11 constituting the polarizing film 13 fixedly without a protective film, that is, without the intention of separating the pressure-sensitive adhesive layer 14 from the polarizing film 13. Has been. The polarizing film 100 with an adhesive layer is used by attaching the adhesive layer 14 to an adherend. As the separator 15, for example, a sheet-shaped base material (liner base material) which has a release layer provided with a release treatment agent on one surface so that the one surface serves as a release surface can be preferably used. The structure of the polarizing film with an adhesive layer is not limited to the embodiment schematically shown in FIG.

<Polarizer>
The polarizer is not particularly limited, and various kinds can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene/vinyl acetate copolymer partially saponified film, and dichroism of iodine or dichroic dye. Examples include polyene-oriented films such as those obtained by adsorbing a substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally 2 to 25 μm. In one embodiment of the present invention, the thickness of the polarizer may be more than 0 μm and 12 μm or less, preferably 1 μm to 10 μm, more preferably 2 μm to 7 μm.

A uniaxially stretched polarizer obtained by dyeing a polyvinyl alcohol film with iodine can be produced, for example, by dyeing a polyvinyl alcohol film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. it can. If necessary, it can be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to wash the stains and anti-blocking agent on the surface of the polyvinyl alcohol-based film, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing is also obtained. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

<Protective film>
The material forming the protective film is preferably one having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic-based polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include a polymer and a polycarbonate polymer. Further, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene/propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers. , 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 polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the protective film. These protective films are usually attached to the polarizer with an adhesive layer. The protective film is made of a thermosetting resin such as a (meth)acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin, or a silicone resin, or an ultraviolet curable resin, which is applied to the polarizer and cured. It can be formed by

Incidentally, the protective film may contain one or more kinds of appropriate additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a coloring agent. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, the high transparency originally possessed by the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, etc. can be used. Examples of the retardation film include those having a front surface retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. When a retardation film is used as the protective film, the retardation film also functions as a polarizer protective film, so that the thickness can be reduced.

The retardation film may be a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, the stretching ratio, and the like are appropriately set depending on the retardation value, the material of the film, and the thickness.

The thickness of the protective film can be appropriately determined, but generally it is preferably 3 to 200 μm, more preferably 3 to 100 μm from the viewpoint of workability such as strength and handleability, and thin layer property. Is preferred. In particular, the thickness of the protective film (when the film is previously formed) is preferably 10 to 60 μm, more preferably 10 to 45 μm from the viewpoint of transportability. On the other hand, the thickness of the protective film (when formed by coating and curing) is preferably 3 to 25 μm, more preferably 3 to 20 μm from the viewpoint of transportability. The protective film may be used in plural sheets or in plural layers.

A functional layer such as a hard coat layer, an antireflection layer, a sticking prevention layer, a diffusion layer or an antiglare layer can be provided on the surface of the protective film to which the polarizer is not adhered. The hard coat layer, the antireflection layer, the antisticking layer, the functional layer such as the diffusion layer and the antiglare layer may be provided on the protective film itself, or may be provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer are laminated via intervening layers such as an adhesive layer, a pressure-sensitive adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that both layers are laminated without an air gap by the intervening layer.

The adhesive layer is formed by an adhesive. The type of adhesive is not particularly limited, and various types can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various types of adhesives such as water-based, solvent-based, hot melt-based and active energy ray-curable adhesives are used. Alternatively, an active energy ray-curable adhesive is suitable.

Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content.

The active energy ray-curable adhesive is an adhesive that is cured by active energy rays such as electron beams and ultraviolet rays (radical curable type, cation curable type), and is, for example, an electron beam curable type or an ultraviolet ray curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photo-radical curable active energy ray curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

Further, when the water-based adhesive or the like is used, it is preferable to apply the adhesive so that the finally formed adhesive layer has a thickness of 30 to 300 nm. The thickness of the adhesive layer is more preferably 60 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferable that the adhesive layer has a thickness of 0.1 to 200 μm. The thickness is more preferably 0.5 to 50 μm, further preferably 0.5 to 10 μm.

In addition, when laminating the polarizer and the protective film, an easily adhesive layer can be provided between the protective film and the adhesive layer.

<Adhesive layer>
The pressure-sensitive adhesive layer used in the present invention contains a base polymer and a silicone oligomer Ps.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer used in the present invention is not particularly limited, and it is a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, a polyvinyl alcohol-based pressure-sensitive adhesive. Adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives and the like can be used. Various base polymers can be used depending on the adhesive used.

Among the above-mentioned pressure-sensitive adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are preferably used. Acrylic pressure-sensitive adhesives are preferably used as those exhibiting such characteristics. A (meth)acrylic polymer is used as the base polymer of the acrylic pressure-sensitive adhesive. The (meth)acrylate contains acrylate and/or methacrylate.

<Base polymer>
In the present invention, a (meth)acrylic polymer is usually used as the base polymer.

(1) Alkyl (meth)acrylate (A)
The (meth)acrylic polymer usually contains, as a monomer unit, an alkyl (meth)acrylate as a main component. As the alkyl (meth)acrylate (A) constituting the main skeleton of the (meth)acrylic polymer, a linear or branched C1 to C20 (meth)acrylic acid alkyl ester can be used. Examples of the C1 to C20 (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. , N-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, ( Hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, Decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, ( Examples include, but are not limited to, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Not done. These (meth)acrylic acid alkyl esters can be used alone or in combination.

In one embodiment of the present invention, the (meth)acrylic polymer may preferably contain one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as a monomer unit. Examples of other (meth)acrylic acid alkyl esters that can be preferably used as the monomer unit of the (meth)acrylic polymer include methyl acrylate, methyl methacrylate (MMA), n-butyl methacrylate (BMA), and methacrylic acid. 2-ethylhexyl (2EHMA) and the like can be mentioned.

In one embodiment of the present invention, the alkyl (meth)acrylate (A) used as a monomer unit of the base polymer has a homopolymer glass transition temperature of −80° C. or higher and 0° C. or lower. The glass transition temperature of the homopolymer of alkyl (meth)acrylate (A) is preferably −70° C. to −5° C., more preferably −60° C. to −10° C.

In one embodiment of the present invention, the alkyl (meth)acrylate (A) used as a monomer unit of the base polymer can be contained in an amount of 80% by weight or more based on the weight of the base polymer. The alkyl (meth)acrylate (A) is preferably 85% by weight or more, more preferably 90% by weight or more, based on the weight of the base polymer.

In a preferred embodiment of the present invention, 80% by weight or more of an alkyl (meth)acrylate (A) having a glass transition temperature of a homopolymer of −80° C. or higher and 0° C. or lower can be contained as a monomer unit of a base polymer. ..

In an embodiment of the present invention, the base polymer further contains, as a monomer unit, an alkyl methacrylate whose glass transition temperature of the homopolymer is 0° C. or higher and 180° C. or lower, preferably 0.1 to 18% by weight. You can The alkyl methacrylate whose homopolymer has a glass transition temperature of 0° C. or higher and 180° C. or lower is more preferably 1 to 15% by weight, further preferably 2.5 to 10% by weight, further more preferably 2.5 to 10% by weight based on the weight of the base polymer. Preferably, the content can be 4% by weight or more and less than 10% by weight.

Examples of the alkyl methacrylate having a homopolymer glass transition temperature of 0° C. or higher and 180° C. or lower include methyl acrylate (Tg: 8° C.), methyl methacrylate (Tg: 105° C.), ethyl methacrylate (Tg: 65° C.), n- Propyl acrylate (Tg: 3°C), n-propyl methacrylate (Tg: 35°C), n-pentyl acrylate (Tg: 22°C), n-tetradecyl acrylate (Tg: 24°C), n-hexadecyl acrylate (Tg : 35° C.), n-hexadecyl methacrylate (Tg: 15° C.), n-stearyl acrylate (Tg: 30° C.), and linear alkyl (meth)acrylates such as n-stearyl methacrylate (Tg: 38° C.); t -Branched alkyl (meta) such as -butyl acrylate (Tg: 43°C), t-butyl methacrylate (Tg: 48°C), i-propyl methacrylate (Tg: 81°C), and i-butyl methacrylate (Tg: 48°C). ) Acrylate; cycloalkyl (meth) such as cyclohexyl acrylate (Tg: 19°C), cyclohexyl methacrylate (Tg: 65°C), isobornyl acrylate (Tg: 94°C), and isobornyl methacrylate (Tg: 180°C). Examples thereof include acrylate. These can be used alone or in combination. Of these, it is preferable to use at least one selected from methyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl acrylate, and isobornyl methacrylate, and selected from methyl acrylate, methyl methacrylate, and isobornyl acrylate. It is more preferable to use at least one of

In one embodiment of the present invention, the polarizing film with the pressure-sensitive adhesive layer may contain the hydroxyl group-containing monomer as a monomer unit in an amount of 0 to 5% by weight as the base polymer (meth)acrylic polymer. The hydroxyl group-containing monomer may be contained more preferably in the range of 0.01 to 1% by weight, and even more preferably 0.1 to 0.5% by weight, based on the weight of the base polymer.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylate. ) 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4 Examples include, but are not limited to, hydroxyalkyl (meth)acrylates such as -hydroxymethylcyclohexyl)methyl (meth)acrylate. In a preferred embodiment of the present invention, the hydroxyl group-containing monomer may be 4-hydroxybutyl acrylate (4-HBA), 2-hydroxybutyl acrylate (2-HBA).

In a preferred embodiment of the present invention, the base polymer comprises, as monomer units, 0.1 to 18% by weight of an alkyl methacrylate having a glass transition temperature of a homopolymer of 0° C. or higher and 180° C. or lower, and 0 to a hydroxyl group-containing monomer. It can be further contained at 5% by weight.

In one embodiment of the present invention, the (meth)acrylic polymer is, in addition to the alkyl (meth)acrylate (A) as a main component, other monomer that is copolymerizable with the alkyl (meth)acrylate, if necessary. It may further contain (copolymerizable monomer). As the copolymerizable monomer, a monomer having a polar group (for example, a carboxy group or a nitrogen atom-containing ring) can be preferably used. The monomer having a polar group can be useful for introducing a cross-linking point in the acrylic polymer and for enhancing the cohesive force of the (meth)acrylic polymer. The copolymerizable monomer may be used alone or in combination of two or more.

Non-limiting specific examples of the copolymerizable monomer include a carboxy group-containing monomer, an acid anhydride group-containing monomer, a sulfonic acid group- or phosphoric acid group-containing monomer, an epoxy group-containing monomer, a cyano group-containing monomer, and an isocyanate group. Containing monomer, amide group-containing monomer, nitrogen atom-containing ring-containing monomer, succinimide skeleton-containing monomer, maleimides, itaconimides, (meth)acrylic acid aminoalkyls, (meth)acrylic acid alkoxyalkyls, vinyl esters, Vinyl ethers, aromatic vinyl compounds, olefins, (meth)acrylic acid esters having alicyclic hydrocarbon groups, (meth)acrylic acid esters having aromatic hydrocarbon groups, and others, tetrahydrofurfuryl (meth)acrylic acid From heterocyclic ring-containing (meth)acrylates, halogen chloride-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicon atom-containing (meth)acrylates such as silicone (meth)acrylates, and terpene compound derivative alcohols The (meth)acrylic acid ester etc. which are obtained are mentioned.

Examples of the carboxy group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like;
Examples of the acid anhydride group-containing monomer include maleic anhydride and itaconic anhydride;
Examples of the monomer having a sulfonic acid group or a phosphoric acid group include styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid. , Sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalene sulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like;
Examples of the epoxy group-containing monomer include epoxy group-containing acrylates such as (meth)acrylic acid glycidyl and (meth)acrylic acid-2-ethylglycidyl ether, allyl glycidyl ether, and (meth)acrylic acid glycidyl ether;
Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.
Examples of the isocyanate group-containing monomer include 2-isocyanatoethyl (meth)acrylate and the like;
Examples of the amide group-containing monomer include (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl( N,N-dialkyl(meth)acrylamides such as (meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(t-butyl)(meth)acrylamide; N-ethyl (meth ) N-alkyl(meth)acrylamides such as acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, Nn-butyl(meth)acrylamide; N-vinylcarboxylic amides such as N-vinylacetamide Others: N,N-dimethylaminopropyl(meth)acrylamide, hydroxyethylacrylamide, N-methylol(meth)acrylamide, N-ethylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl( (Meth)acrylamide, N-methoxyethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-(meth)acryloylmorpholine and the like;
Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl -3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N -Vinylthiazole, N-vinylisothiazole, N-vinylpyridazine and the like (for example, lactams such as N-vinyl-2-caprolactam);
Examples of the monomer having a succinimide skeleton include N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyhexamethylenesuccinimide and the like. Given;
Examples of the maleimides include N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide and the like;
Examples of itaconimides include N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, N -Lauryl itaconimide and the like;
Examples of aminoalkyl (meth)acrylates include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and (meth)acrylic. T-butylaminoethyl acid acid;
Examples of the alkoxyalkyl (meth)acrylates include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and (meth)acrylic acid. Ethoxypropyl and the like can be mentioned;
Examples of vinyl esters include vinyl acetate, vinyl propionate and the like;
Examples of vinyl ethers include vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether;
Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluene and the like;
Examples of olefins include ethylene, butadiene, isoprene, and isobutylene;
Examples of the (meth)acrylic acid ester having an alicyclic hydrocarbon group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like;
Examples of the (meth)acrylic acid ester having an aromatic hydrocarbon group include phenyl(meth)acrylate, phenoxyethyl(meth)acrylate, and benzyl(meth)acrylate.

When such a copolymerizable monomer is used, the amount thereof is not particularly limited, but it is usually suitable to be 0.01% by weight or more of the total amount of the monomer components. From the viewpoint of better exerting the effect of using the copolymerizable monomer, the amount of the copolymerizable monomer used may be 0.1% by weight or more, or 1% by weight or more based on the total amount of the monomer components. The amount of the copolymerizable monomer used can be 50% by weight or less, and preferably 40% by weight or less, based on the total amount of the monomer components. This can prevent the cohesive force of the pressure-sensitive adhesive from becoming too high, and improve the tackiness at room temperature (25° C.).

In one embodiment of the present invention, the (meth)acrylic polymer is, in addition to the alkyl (meth)acrylate as a main component, optionally a hydroxyl group-containing monomer (typically, as described above) as a monomer unit. , A (meth)acrylic monomer containing a hydroxyl group). Examples of the hydroxyl group-containing monomer include, as described above, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxy (meth)acrylate. Hydroxypropyl, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-(meth)acrylic acid Examples thereof include hydroxyalkyl (meth)acrylate such as hydroxylauryl, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, and the like, 2-hydroxyethyl (meth)acrylate, 4-hydroxy (meth)acrylate. Butyl, 6-hydroxyhexyl (meth)acrylate and the like can be preferably used. Among these, preferable examples include 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA). By using the hydroxyl group-containing monomer, the cohesive force and polarity of the pressure-sensitive adhesive can be adjusted and the pressure-sensitive adhesive force after heating can be improved. Further, the hydroxyl group-containing monomer can also serve to suppress the decrease in transparency due to moisture by increasing the hydrophilicity of the pressure-sensitive adhesive layer. When the hydroxyl group-containing monomer is included, the amount of the hydroxyl group-containing monomer to be used is not particularly limited, but usually 0.01% by weight or more, 0.1% by weight or more, based on the total amount of the monomer unit for preparing the (meth)acrylic polymer. It can be 1% by weight or more, 0.5% by weight or more.

In addition, in one embodiment of the present invention, the (meth)acrylic polymer is, in addition to the alkyl (meth)acrylate as the main component, a polyfunctional polymer for the purpose of adjusting the cohesive force of the pressure-sensitive adhesive layer, if necessary. It may contain a polymerizable monomer. Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, Pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecane Diol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, vinyl(meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl Examples thereof include diol (meth)acrylate and hexyl diol di(meth)acrylate. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate and dipentaerythritol hexa(meth)acrylate can be preferably used. The polyfunctional monomers may be used alone or in combination of two or more. The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, etc., but is usually 0.01% by weight to 3.0% by weight based on the total amount of the monomer components for preparing the alkyl (meth)acrylate (A). It is suitable to set it in the range of wt%, and it may be 0.02 wt% to 2.0 wt% or 0.03 wt% to 1.0 wt%.

(2) Polar monomer (B)
In one embodiment of the present invention, the base polymer contains, as a copolymerizable monomer unit, at least one polar monomer (B) selected from the group consisting of a carboxyl group-containing monomer (b1) and a nitrogen-containing monomer (b2). It can also be included.

In an embodiment of the present invention, the polar monomer (B) may be included in an amount of 0 to 5% by weight based on the weight of the base polymer. The polar monomer (B) is preferably 0.1 to 3% by weight, more preferably 1 to 2% by weight, based on the weight of the base polymer.

(2-1) Carboxyl group-containing monomer (b1)
In the present invention, the base polymer may contain a carboxyl group-containing monomer (b1) as a copolymerizable monomer unit. Examples of the carboxy group-containing monomer (b1) include, but are not limited to, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like. .. In a preferred embodiment of the present invention, the carboxyl group-containing monomer (b1) may be acrylic acid or methacrylic acid. In a more preferred embodiment of the present invention, the carboxyl group-containing monomer (b1) may be acrylic acid (AA).

(2-2) Nitrogen-containing monomer (b2)
In the present invention, the base polymer may include a nitrogen-containing monomer (b2) as a copolymerizable monomer unit. Examples of the nitrogen-containing monomer (b2) include vinyl monomers having a lactam ring (for example, vinylpyrrolidone monomers such as N-vinylpyrrolidone and methylvinylpyrrolidone, β-lactam ring, δ-lactam ring, and ε-). Vinyllactam-based monomers having a lactam ring such as lactam ring); Maleimide-based monomers such as maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N , N-diethyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N -(N-substituted)amide-based monomers such as methylolpropane (meth)acrylamide; aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, (meth) Aminoalkyl-based (meth)acrylate monomers such as t-butylaminoethyl acrylate and 3-(3-pyridinyl)propyl(meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6 -Succinimide-based monomers such as oxyhexamethylene succinimide and N-(meth)acryloyl-8-oxyoctamethylene succinimide; Cyano (meth)acrylate-based monomers such as acrylonitrile and methacrylonitrile; vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine , Vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides and the like, but are not limited thereto. In a preferred embodiment of the present invention, the nitrogen-containing monomer (b2) may be N-vinylpyrrolidone, methylvinylpyrrolidone, N,N-dimethyl(meth)acrylamide. In a more preferred embodiment of the present invention, the nitrogen-containing monomer (b2) may be N-vinylpyrrolidone.

The method for obtaining the (meth)acrylic polymer is not particularly limited, and various known methods for synthesizing acrylic polymers, such as solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method, and photopolymerization method. The above-mentioned polymerization method can be appropriately adopted. In some embodiments, the solution polymerization method may be preferably adopted. The polymerization temperature at the time of performing solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., and is, for example, about 20°C to 170°C (typically 40°C to 140°C). C.).

The initiator used for the polymerization can be appropriately selected from conventionally known thermal polymerization initiators, photopolymerization initiators, etc. according to the polymerization method. The polymerization initiators may be used alone or in combination of two or more.

Examples of the thermal polymerization initiator include azo polymerization initiators (eg, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis( 2-methylpropionic acid)dimethyl, 4,4′-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2′-azobis(2-amidinopropane)dihydrochloride, 2,2′-azobis[2 -(5-Methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(N,N'-dimethylene Isobutylamidine) dihydrochloride, etc.); Persulfate such as potassium persulfate; Peroxide type polymerization initiator (eg, dibenzoyl peroxide, t-butyl permaleate, lauroyl peroxide, etc.); Redox type polymerization initiator, etc. Is mentioned. The amount of the thermal polymerization initiator used is not particularly limited, but is, for example, 0.01 parts by weight to 5 parts by weight, preferably 0.05 parts by weight to 100 parts by weight of the monomer component used for preparing the acrylic polymer. The amount can be within the range of 3 parts by weight.

The photopolymerization initiator is not particularly limited, and examples thereof include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, and photoactivators. Oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, benzophenone photopolymerization initiator, ketal photopolymerization initiator, thioxanthone photopolymerization initiator, acylphosphine oxide photopolymerization initiator Agents and the like can be used. The amount of the photopolymerization initiator used is not particularly limited, but for example, 0.01 part by weight to 5 parts by weight, preferably 0.05 part by weight to 100 parts by weight of the monomer component used for the preparation of the acrylic polymer. The amount can be within the range of 3 parts by weight.

In one embodiment of the present invention, the (meth)acrylic polymer is solution-polymerized by using, for example, ethyl acetate, toluene or the like as a polymerization solvent in a mixture of the above-mentioned monomer component and a polymerization initiator. A (meth)acrylic polymer can be obtained. As an example of solution polymerization, the reaction is usually carried out under a stream of an inert gas such as nitrogen with a polymerization initiator at about 50 to 70° C. for about 5 to 30 hours. The pressure-sensitive adhesive layer disclosed in the present specification can be formed using, for example, a pressure-sensitive adhesive composition containing the (meth)acrylic polymer, the silicone oligomer Ps described below, and other additives.

In the present invention, the weight average molecular weight Mw of the above-mentioned base polymer may be 500,000 to 2,500,000. In one embodiment of the present invention, the weight average molecular weight Mw of the base polymer may be preferably 700,000 to 2.7 million, more preferably 800,000 to 2.5 million.

<Silicone Oligomer Ps>
In the present invention, the pressure-sensitive adhesive layer contains silicone oligomer Ps. Silicone oligomer Ps can function as a tackiness increase retarder that contributes to suppression of initial tackiness and improvement of tackiness increase ratio due to the low polarity and mobility of the siloxane structure. As the silicone oligomer Ps, a polymer having a siloxane structure in its side chain can be preferably used.

The silicone oligomer Ps used in the present invention has a glass transition temperature (Tg) in the range of -50°C to 100°C. In one embodiment of the present invention, the Tg of the silicone oligomer Ps may preferably be -30°C or higher and 70°C or lower, and more preferably -20°C or higher and 60°C or lower. When the Tg of the silicone oligomer Ps is in the above range, it is possible to achieve both a low initial tackiness and an increase in tackiness during use (strong tackiness) at a high level.

The silicone oligomer Ps used in the present invention has a weight average molecular weight Mw of 10,000 or more and 300,000 or less. In one embodiment of the present invention, the weight average molecular weight Mw of the silicone oligomer Ps may be preferably 12,500 or more and 2500000 or less, more preferably 15000 or more and 2000000 or less. When the weight average molecular weight Mw of the silicone oligomer Ps is within the above range, it is easy to adjust the compatibility and mobility in the pressure-sensitive adhesive layer to an appropriate range, and the initial low tackiness and strong tackiness during use are high. It becomes easier to realize a pressure-sensitive adhesive sheet that is compatible at both levels.

In a preferred embodiment of the present invention, the silicone oligomer Ps has a Tg of −50° C. or higher and 100° C. or lower, a side chain silicone functional group equivalent of 1000 to 20000 g/mol, and a weight average molecular weight Mw of 10,000 or more and 300,000 or less. May be

In one embodiment of the present invention, the silicone oligomer Ps may include a monomer S1 having a polyorganosiloxane skeleton and a monomer having a homopolymer glass transition temperature of −70° C. or higher and 180° C. or lower as monomer units.

(1) Monomer S1 having a polyorganosiloxane skeleton
The monomer S1 having a polyorganosiloxane skeleton that can be used in the silicone oligomer Ps of the present invention is not particularly limited, and any monomer having a polyorganosiloxane skeleton can be used. Examples of the polyorganosiloxane skeleton include, but are not limited to, trimethylsiloxane (TM), dimethylsiloxane (DM), polyoxyethylmethylsiloxane (EOM), and the like.

As the monomer S1 having a polyorganosiloxane skeleton, for example, a compound represented by the following general formula (1) or (2) can be used. More specifically, as one-end reactive silicone oil manufactured by Shin-Etsu Chemical Co., Ltd., X-22-174ASX, X-22-2426, X-22-2475, KF-2012, X-22-174BX, X -22-2404 and the like. The monomer S1 having a polyorganosiloxane skeleton may be used alone or in combination of two or more.

Here, R ³ in the general formulas (1) and (2) is hydrogen or methyl, R ⁴ is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

The silicone oligomer Ps used in the present invention has a silicone functional group equivalent of its side chain of 1000 to 20000 g/mol. In one embodiment of the present invention, the silicone functional group equivalent of the side chain of the silicone oligomer Ps may be preferably 1200 to 18000 g/mol, more preferably 1500 to 15000 g/mol. When the silicone functional group equivalent of the side chain of the silicone oligomer Ps is within the above range, it is easy to adjust the compatibility (for example, the compatibility with the base polymer) and the mobility in the pressure-sensitive adhesive layer to an appropriate range and It becomes easy to realize a pressure-sensitive adhesive sheet that achieves both low tackiness and strong tackiness during use at a high level.

Here, the “functional group equivalent” means the weight of the main skeleton (for example, polydimethylsiloxane) bonded to each functional group. The unit of g/mol is converted to 1 mol of the functional group. The functional group equivalent of the monomer S1 having a polyorganosiloxane skeleton can be calculated from the spectrum intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR), for example. Calculation of the functional group equivalent (g/mol) of the monomer S1 having a polyorganosiloxane skeleton based on the ¹ H-NMR spectrum intensity is necessary based on a general structural analysis method related to ¹ H-NMR spectrum analysis. In that case, it can be performed by referring to the description of Japanese Patent No. 5915153.

When two or more kinds of monomers having different functional group equivalents are used as the monomer S1 having a polyorganosiloxane skeleton, an arithmetic average value can be used as the functional group equivalent of the monomer S1. That is, the functional group equivalent of the monomer S1 composed of n kinds of monomers (monomer S1 ₁ , monomer S1 ₂ ... Monomer S1 _n ) having different functional group equivalents can be calculated by the following formula.
Functional group equivalent of the monomer S1 (g / mol) = (monomer S1 ₁ functional group equivalent × monomer S1 ₁ of the amount + monomer S1 ₂ functional group equivalent × monomer S1 ₂ of the amount + ... + monomer S1 _n Functional group equivalent×monomer S1 _n blending amount)/(monomer S1 ₁ blending amount+monomer S1 ₂ blending amount+...+monomer S1 _n blending amount)

The content of the monomer S1 having a polyorganosiloxane skeleton may be, for example, 5% by weight or more based on the total monomer components for preparing the silicone oligomer Ps, and the effect as a tackiness increase retarder can be better exhibited. From the viewpoint of the above, the amount is preferably 10% by weight or more, and may be 15% by weight or more. In some embodiments, the content of the monomer S1 may be, for example, 20% by weight or more. From the viewpoint of polymerization reactivity and compatibility, the content of the monomer S1 having a polyorganosiloxane skeleton is appropriately 60% by weight or less based on the total monomer components for preparing the silicone oligomer Ps. Yes, it may be 50% by weight or less, 40% by weight or less, or 30% by weight or less. When the content of the monomer S1 having a polyorganosiloxane skeleton is within the above range, it is easy to realize a pressure-sensitive adhesive sheet that achieves a high level of both low initial tackiness and increase in tackiness (strong tackiness) during use. Become.

(2) Monomer whose homopolymer has a glass transition temperature of −70° C. or higher and 180° C. or lower The silicone oligomer Ps of the present invention is a (meth)acryl-based monomer or another monomer copolymerizable with the monomer S1 having the polyorganosiloxane skeleton. It contains a copolymerizable monomer. As the copolymerizable (meth)acrylic monomer or other copolymerizable monomer that can be used in the silicone oligomer Ps of the present invention, a homopolymer having a glass transition temperature of −70° C. to 180° C. is used. Examples thereof include, but are not limited to, (meth)acrylic acid alkyl ester and (meth)acrylic acid ester having an alicyclic hydrocarbon group. Examples of the (meth)acrylic acid alkyl ester include methyl methacrylate (MMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2-EHMA), butyl acrylate (BA), and 2-ethylhexyl acrylate (2-EHA). Examples of the (meth)acrylic acid ester having an alicyclic hydrocarbon group include 2-((3-hydroxymethyl)-adamantan-1-yl)methoxy-2-oxoethyl methacrylate (2EHAMA), cyclopentyl (meth)acrylate, Examples thereof include, but are not limited to, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, and the like. In one embodiment of the present invention, at least one selected from 2-((3-hydroxymethyl)-adamantan-1-yl)methoxy-2-oxoethyl methacrylate (2EHAMA) and isobornyl methacrylate (IBXMA) is a monomer unit. Can be included as In another embodiment of the present invention, it may contain at least one selected from dicyclopentanyl methacrylate, isobornyl methacrylate and cyclohexyl methacrylate as a monomer unit. These monomers may be used alone or in combination of two or more.

The amount of the above-mentioned (meth)acrylic acid alkyl ester and the above-mentioned (meth)acrylic acid ester having an alicyclic hydrocarbon group used is, for example, 10% by weight or more and 95% by weight or more based on all the monomer components for preparing the silicone oligomer Ps. May be 20% by weight or more, 95% by weight or less, 30% by weight or more and 90% by weight or less, or 40% by weight or more and 90% by weight or less, It may be 50% by weight or more and 85% by weight or less.

As another example of the monomer that can be included together with the monomer S1 as a monomer unit constituting the silicone oligomer Ps, a carboxyl group-containing monomer and an acid anhydride group-containing monomer exemplified above as the monomer that can be used in the alkyl (meth)acrylate (A) are included. Monomer, hydroxyl group-containing monomer, epoxy group-containing monomer, cyano group-containing monomer, isocyanate group-containing monomer, amide group-containing monomer, nitrogen atom-containing ring-containing monomer, succinimide skeleton-containing monomer, maleimides, itaconimides, (meth)acrylic Acid aminoalkyls, vinyl esters, vinyl ethers, olefins, aromatic hydrocarbon group-containing (meth)acrylic acid esters, heterocycle-containing (meth)acrylates, halogen atom-containing (meth)acrylates, terpene compound derivative alcohols The (meth)acrylic acid ester etc. which are obtained are mentioned.

As still another example of the monomer that can be included together with the monomer S1 as a monomer unit constituting the silicone oligomer Ps, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di Oxyalkylene di(meth)acrylates such as (meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate; monomers having a polyoxyalkylene skeleton, for example polyethylene Polyoxyalkylene chain such as glycol or polypropylene glycol has a polymerizable functional group such as (meth)acryloyl group, vinyl group or allyl group at one end and an ether structure (alkyl ether, aryl ether, aryl) at the other end. Polymerizable polyoxyalkylene ether having alkyl ether, etc.; methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, (meth)acrylic acid Alkoxyalkyl (meth)acrylates such as ethoxypropyl; salts such as alkali metal salts of (meth)acrylic acid; polyvalent (meth)acrylates such as trimethylolpropane tri(meth)acrylic acid ester: vinylidene chloride, (meth)acrylic Halogenated vinyl compounds such as acid-2-chloroethyl; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline and other oxazoline group-containing monomers; (meth) Aziridine group-containing monomers such as acryloyl aziridine and 2-aziridinylethyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, lactones and (meth) Hydroxyl group-containing vinyl monomer such as adduct with 2-hydroxyethyl acrylate; Fluorine-containing vinyl monomer such as fluorine-substituted (meth)acrylic acid alkyl ester; Reactive halogen-containing vinyl such as 2-chloroethyl vinyl ether and monochlorovinyl acetate Monomers: vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxysilane Silicon-containing vinyl monomers; other macromonomers having a radically polymerizable vinyl group at the terminal of a vinyl group-polymerized monomer; and the like. These can be copolymerized alone or in combination with the monomer S1.

In an embodiment in which the monomer component used for the preparation of the silicone oligomer Ps includes the monomer S1 and the (meth)acrylic monomer, the total amount of the monomer S1 and the (meth)acrylic monomer in the entire monomer component is, for example, 50% by weight. The amount may be 70% by weight or more, 85% by weight or more, 90% by weight or more, 95% by weight or more, or substantially 100% by weight.

The composition of the (meth)acrylic monomer contained in the monomer component can be set such that the glass transition temperature T _m1 based on the composition of the (meth)acrylic monomer is higher than 0° C., for example. Here, the glass transition temperature T _m1 based on the composition of the (meth)acrylic monomer is based on the composition of only the (meth)acrylic monomer among the monomer components used for the preparation of the silicone oligomer Ps, and according to the Fox equation. Refers to the required Tg. T _m1 is the glass transition temperature of the homopolymer of each (meth)acrylic monomer, which is obtained by applying the above-described Fox equation to only the (meth)acrylic monomer among the monomer components used for the preparation of the silicone oligomer Ps. And the weight fraction of each (meth)acrylic monomer in the total amount of the (meth)acrylic monomer. With the silicone oligomer Ps having a glass transition temperature T _m1 higher than 0° C., the initial adhesive force is easily suppressed. Further, by using the silicone oligomer Ps having a glass transition temperature T _m1 higher than 0° C., it is easy to obtain a pressure-sensitive adhesive sheet having a large adhesive force increase ratio.

In some embodiments, T _m1 may be −20° C. or higher, −10° C. or higher, 0° C. or higher, or 10° C. or higher. At higher T _m1, the tack force at the beginning of application generally tends to be better suppressed. Further, T _m1 may be, for example, 90° C. or lower, 80° C. or lower, 70° C. or lower, or lower than 70° C. When T _m1 is low, the increase in adhesive strength due to heating tends to be facilitated. The technique disclosed herein can be preferably carried out using a silicone oligomer Ps whose T _m1 is, for example, in the range of −20° C. to 90° C., or −10° C. to 80° C., and 0° C. to 70° C.

The silicone oligomer Ps can be produced, for example, by polymerizing the above-mentioned monomer by a known method such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or a photopolymerization method.

A chain transfer agent can be used to adjust the molecular weight of the silicone oligomer Ps. Examples of the chain transfer agent to be used include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol and α-thioglycerol; thioglycolic acid, methyl thioglycolate, Ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, ethylene Examples thereof include thioglycolic acid esters such as thioglycolic acid ester of glycol, thioglycolic acid ester of neopentyl glycol, and thioglycolic acid ester of pentaerythritol; α-methylstyrene dimer; and the like.

The amount of the chain transfer agent used is not particularly limited, but is usually 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight with respect to 100 parts by weight of the monomer. And more preferably 0.2 to 10 parts by weight. By adjusting the addition amount of the chain transfer agent in this way, a silicone oligomer Ps having a suitable molecular weight can be obtained. The chain transfer agents may be used alone or in combination of two or more.

In an embodiment of the present invention, the silicone oligomer Ps may be included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the above-mentioned (meth)acrylic polymer that is the base polymer. In the embodiment of the present invention, the silicone oligomer Ps is preferably contained in an amount of 0.25 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the above-mentioned (meth)acrylic polymer. May be included in the section. When the content of the silicone oligomer Ps contained in the adhesive layer is within the above range, the initial adhesive force can be suppressed and a higher adhesive force after heating can be obtained.

Incidentally, the silicone oligomer Ps as described above can function favorably as an agent for increasing the adhesive strength by being mixed in the adhesive layer. The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in a mode in which the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a base polymer and a pressure-sensitive adhesive force increase retarder, and the pressure-sensitive adhesive force increase retarder contains a silicone oligomer Ps. Here, the silicone oligomer Ps functions as an adhesive force increase retarder because the initial adhesive force is suppressed by the silicone oligomer Ps existing on the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet from before attachment to the adherend and in the initial stage of attachment. As a result, the amount of the silicone oligomer Ps present on the surface of the pressure-sensitive adhesive layer decreases due to the pressure-sensitive adhesive flowing due to the passage of time after application, heating, etc., and the silicone oligomer Ps is compatible with the pressure-sensitive adhesive, increasing the adhesive strength. Conceivable. Therefore, as the above-mentioned adhesive force increase retarder in the technology disclosed herein, other materials capable of exhibiting the same kind of function may be used instead of the silicone oligomer Ps or in combination with the silicone oligomer Ps. A non-limiting example of such a material is a polymer having a polyoxyalkylene structure in the molecule (hereinafter, also referred to as “polymer Po”). The polymer Po can be, for example, a polymer including a monomer unit derived from a monomer having a polyoxyalkylene skeleton. Specific examples thereof include homopolymers or copolymers of any one of the above-mentioned monomers having a polyoxyalkylene skeleton, and one or more of monomers having a polyoxyalkylene skeleton and others. A copolymer with the monomer (eg, a (meth)acrylic monomer) or the like can be used as the polymer Po. The amount of the monomer having a polyoxyalkylene skeleton is not particularly limited, but for example, the amount of the monomer S1 used in the silicone oligomer Ps described above may be applied to the amount of the monomer having a polyoxyalkylene skeleton in the polymer Po. You can The amount of the polymer Po used in the pressure-sensitive adhesive layer is not particularly limited. For example, the amount of the silicone oligomer Ps used for the base polymer described above can be applied to the amount of the polymer Po used for the base polymer. Alternatively, a part of the amount of the silicone oligomer Ps used with respect to the above-mentioned base polymer (for example, about 5% by weight to 95% by weight, or about 15% by weight to 85% by weight of the total amount of the silicone oligomer Ps used, or 30 % To about 70% by weight) may be replaced with the polymer Po.

In one embodiment of the present invention, the melting temperature of the silicone oligomer Ps may be -20 to 120°C. In another embodiment of the present invention, the melting temperature of the silicone oligomer Ps may be −10 to 90° C., 0 to 80° C.

<Other ingredients>
(Crosslinking agent)
A crosslinking agent may be used in the pressure-sensitive adhesive layer disclosed in the present specification for the purpose of adjusting cohesive force and the like. As the cross-linking agent, a commonly used cross-linking agent can be used, and examples thereof include epoxy cross-linking agents, isocyanate cross-linking agents, silicone cross-linking agents, oxazoline cross-linking agents, aziridine cross-linking agents, silane cross-linking agents, alkyl etherifications. Examples thereof include a melamine-based crosslinking agent and a metal chelate-based crosslinking agent. In particular, an isocyanate cross-linking agent, an epoxy cross-linking agent, and a metal chelate cross-linking agent can be preferably used. The cross-linking agents can be used alone or in combination of two or more.

Specifically, examples of the isocyanate cross-linking agent include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene. Examples thereof include diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and adducts of these with polyols such as trimethylolpropane. Alternatively, a compound having at least one or more isocyanate group and one or more unsaturated bond in one molecule, specifically 2-isocyanatoethyl (meth)acrylate, etc., should also be used as an isocyanate cross-linking agent. You can These may be used alone or in combination of two or more.

Epoxy crosslinking agents include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane tri Glycidyl ether, diglycidyl aniline, diamine glycidyl amine, N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane You can These may be used alone or in combination of two or more.

Examples of the metal chelate compound include aluminum, iron, tin, titanium and nickel as metal components, and acetylene, methyl acetoacetate and ethyl lactate as chelate components. These may be used alone or in combination of two or more.

The amount of the crosslinking agent used can be, for example, 0.01 part by weight or more, and preferably 0.05 part by weight or more, based on 100 parts by weight of the base polymer. A higher cohesive force tends to be obtained by increasing the amount of the crosslinking agent used. In some embodiments, the amount of the cross-linking agent used may be 0.05 parts by weight or more, may be 0.1 parts by weight or more, and may be 0.2 parts by weight or more based on 100 parts by weight of the base polymer. It may be. On the other hand, from the viewpoint of avoiding a decrease in tack due to excessive improvement in cohesive force, the amount of the cross-linking agent to be used is usually 15 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the base polymer. It may be 5 parts by weight or less. In the PSA having a composition containing the silicone oligomer Ps or the other PSA retarder, the use amount of the crosslinking agent is not too large. It may be advantageous from the viewpoint of good expression.

The technique disclosed in the present specification can be preferably carried out in a mode in which at least an isocyanate cross-linking agent is used as the cross-linking agent. From the viewpoint of facilitating the realization of a pressure-sensitive adhesive sheet having a high cohesive force after heating and a high adhesive force increase ratio, in some embodiments, the amount of the isocyanate-based cross-linking agent based on 100 parts by weight of the base polymer is, for example, 5 parts by weight or less. It may be 3 parts by weight or less, 1 part by weight or less, 0.7 parts by weight or less, and 0.5 parts by weight or less.

A cross-linking catalyst may be used in order to more effectively promote any of the above-mentioned cross-linking reactions. As the crosslinking catalyst, for example, a tin-based catalyst (particularly dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst used is not particularly limited, but can be, for example, approximately 0.0001 parts by weight to 1 part by weight with respect to 100 parts by weight of the base polymer.

(Silane coupling agent)
The pressure-sensitive adhesive layer disclosed in the present specification may further contain a silane coupling agent. The durability can be improved by using the silane coupling agent. As the silane coupling agent, one having any appropriate functional group can be used. Specific examples of the functional group include a vinyl group, an epoxy group, an amino group, a mercapto group, a (meth)acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, and a polysulfide group. Specifically, for example, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, and vinyltributoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycine Epoxy group-containing silane coupling agents such as cidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N-(1,3-dimethylbutylidene) Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane; mercapto group-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane; p-styryltrimethoxysilane and other styryls Group-containing silane coupling agent; (meth)acryl group-containing silane coupling agent such as γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane; isocyanate group-containing silane such as 3-isocyanatepropyltriethoxysilane Coupling agents; polysulfide group-containing silane coupling agents such as bis(triethoxysilylpropyl) tetrasulfide and the like. As the silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane and γ-mercaptopropylmethyldimethoxysilane are preferably used. You can

The silane coupling agent may be used alone or in combination of two or more kinds, but the total content is 100 parts by weight of the base polymer and the silane coupling agent. The amount is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, further preferably 0.02 to 1 part by weight, further preferably 0.05 to 0.6 part by weight.

In addition, the pressure-sensitive adhesive layer in the technique disclosed herein is a tackifier, a leveling agent, a plasticizer, a softening agent, a colorant (a dye, a pigment, etc.), a filler, etc. within a range that does not significantly impair the effects of the present invention. If necessary, known additives such as antistatic agents, antiaging agents, ultraviolet absorbers, antioxidants, light stabilizers and preservatives that can be used for pressure-sensitive adhesives may be included.

(Formation of adhesive layer)
As a method for forming a pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive composition is applied to a release-treated separator or the like, and a polymerization solvent or the like is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to a polarizing film, or It is prepared by a method of applying the above-mentioned pressure-sensitive adhesive composition to a polarizing film, drying and removing a polymerization solvent and the like to form an adhesive layer on the polarizing film. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of forming the pressure-sensitive adhesive layer by applying the adhesive composition of the present invention on such a liner, and drying the pressure-sensitive adhesive layer, as a method for drying the pressure-sensitive adhesive, an appropriate method is appropriately adopted depending on the purpose. obtain. Preferably, a method of heating and drying the above coating film is used. The heat drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. By setting the heating temperature in the above range, a pressure-sensitive adhesive having excellent pressure-sensitive adhesive properties can be obtained.

As for the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Also, an anchor layer can be formed on the surface of the polarizing film, or an adhesive layer can be formed after various types of easy adhesion treatment such as corona treatment and plasma treatment. Further, the surface of the pressure-sensitive adhesive layer may be subjected to easy adhesion treatment.

Various methods are used to form the adhesive layer. 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. Examples of the method include an extrusion coating method.

The thickness of the adhesive layer is not particularly limited and is, for example, about 1 to 100 μm. The thickness is preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release-treated sheet (separator) until practical use.

As a constituent material of the separator, for example, polyethylene, polypropylene, polyethylene terephthalate, a plastic film such as a polyester film, a porous material such as paper, cloth, non-woven fabric, a net, a foamed sheet, a metal foil, and a laminated body thereof are appropriately used. Examples thereof include plastic thin films, and plastic films are preferably used because they have excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film and vinyl chloride. Examples thereof include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films and the like.

The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. In the separator, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder or the like, coating type, kneading type, vapor deposition type It is also possible to perform antistatic treatment such as. Particularly, by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator, the peelability from the pressure-sensitive adhesive layer can be further enhanced.

The release-treated sheet used in the production of the pressure-sensitive adhesive layer-attached polarizing film can be used as it is as a separator for the pressure-sensitive adhesive layer-attached polarizing film, which simplifies the process.

The present invention will be described below with reference to examples, but the present invention is not limited to the examples shown below. In addition, all parts and% in each example are based on weight. Unless otherwise specified below, the room temperature standing condition is 23° C. and 65% RH.

The weight average molecular weight Mw of each of the following polymers was determined by using a GPC device (manufactured by Tosoh Corporation, HLC-8220GPC) under the following conditions, and calculated in terms of polystyrene.
-Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)
・Sample injection volume: 10 μl
・Eluent: THF ・Flow rate: 0.6 ml/min
・Measuring temperature: 40℃

<Preparation of one-sided protective polarizing film B>
(Production of Polarizer B)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75° C. was corona-treated on one side of the substrate, and the corona-treated surface was treated with polyvinyl Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing the product name "Gosephimmer Z200") in a ratio of 9:1 was applied and dried at 25°C to form a PVA-based resin layer having a thickness of 11 µm, and a laminate was prepared. The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120° C. (in-air auxiliary stretching treatment). Next, the laminated body was immersed in an insolubilizing bath having a liquid temperature of 30° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment). Then, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and 1.0 part by weight of potassium iodide was added, and the resultant was immersed for 60 seconds in an aqueous iodine solution (dyeing treatment). .. Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30° C. (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water). (Crosslinking treatment). Then, the laminate was immersed in an aqueous boric acid solution having a liquid temperature of 70° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water). On the other hand, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) such that the total stretching ratio was 5.5 times (underwater stretching treatment). After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment). As described above, an optical film laminate including a polarizer having a thickness of 5 μm and a boric acid content of 16% was obtained. The boric acid content in the polarizer was measured by the following method.

About the obtained polarizer B, a Fourier transform infrared spectrophotometer (FTIR) (manufactured by Perkin Elmer, trade name “SPECTRUM2000”) was used to measure the total reflection attenuation spectroscopy (ATR) using polarized light as the measurement light. The intensity of the acid peak (665 cm ^-1 ) and the intensity of the reference peak (2941 cm ^-1 ) were measured. The boric acid content index was calculated from the obtained boric acid peak strength and the reference peak strength by the following formula, and the boric acid content (wt%) was determined from the calculated boric acid content index by the following formula.
(Boric acid content index)=(strength of boric acid peak 665 cm ⁻¹ )/(strength of reference peak 2941 cm ⁻¹ )
(Boric acid content (% by weight))=(Boric acid content index)×5.54+4.1

(Preparation of transparent protective film B)
Transparent protective film B: A protective film having a thickness of 40 μm and having a lactone ring structure was used after being subjected to corona treatment on the surface for easy adhesion treatment.

(Preparation of adhesive applied to transparent protective film B)
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO) and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare an ultraviolet curable adhesive.

(Preparation of one-sided protective polarizing film B)
After laminating the transparent protective film B on the surface of the polarizer of the optical film laminate while applying the ultraviolet curable adhesive so that the thickness of the adhesive layer after curing becomes 0.5 μm, Ultraviolet rays were irradiated as active energy rays to cure the adhesive.

(Active energy ray)
Ultraviolet irradiation was performed using a gallium-encapsulated metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER10, bulb: V bulb, peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380 to 440 nm). ) Was used and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.

Next, the amorphous PET substrate was peeled off, and a one-sided protective polarizing film B using a thin polarizer was produced. The single-sided transmittance T and the polarization degree P of the polarizer B were measured by the following method using the obtained one-sided protective polarizing film B. The single-sided transmittance T of the polarizer B was 42.8%. The polarization degree P was 99.99%.

The single transmittance T and the polarization degree P of the polarizer B of the obtained one-sided protective polarizing film B were measured using a spectral transmittance measuring instrument with integrating sphere (Dot-3c of Murakami Color Research Laboratory). The degree of polarization P is the transmissivity (parallel transmissivity: Tp) when two identical piece protective polarizing films B are superposed so that their transmissive axes are parallel to each other, and the transmissive axes of both are orthogonal to each other. It is obtained by applying the transmittance (orthogonal transmittance: Tc) in the case of overlapping in this way to the following formula.
Polarization degree P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100
Each transmittance is represented by a Y value which is adjusted by the 2° visual field (C light source) of JIS Z8701 for the luminosity, with 100% of the completely polarized light obtained through the Glan-Teller prism polarizer.

<Production of both protective polarizing films A>
(Production of Polarizer A)
A polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% and a thickness of 75 μm was dipped in warm water at 30° C. for 60 seconds to be swollen. Next, the film was immersed in an aqueous solution of iodine/potassium iodide (weight ratio=0.5/8) having a concentration of 0.3%, and the film was dyed while stretching up to 3.5 times. Then, stretching was performed in a boric acid ester aqueous solution at 65° C. so that the total stretching ratio was 6 times. After stretching, it was dried in an oven at 40° C. for 3 minutes to obtain a PVA-based polarizer A (SP value 32.8, thickness 23 μm). The water content was 14% by weight.

(Preparation of transparent protective film A)
The acrylic resin film (SP value 22.2) having a thickness of 40 μm and a water vapor transmission rate of 60 g/m ² /24 h was subjected to corona treatment before use.

(Active energy ray)
As active energy rays,
・Ultraviolet irradiation device (gallium-encapsulated metal halide lamp): Fusion UV Systems, Inc. Light HAMMER10
・Valve: V valve ・Peak illuminance: 1600 mW/cm ² ,
An integrated dose of 1000/mJ/cm ² (wavelength 380 to 440 nm) was used. The illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.

(Preparation of active energy ray-curable adhesive (1))
38.3 parts of N-hydroxyethylacrylamide (SP value 29.6, homopolymer Tg123° C., manufactured by Kojinsha) as the radically polymerizable compound (A), and tripropylene glycol as the radically polymerizable compound (B). 19.1 parts of diacrylate (trade name: Aronix M-220, SP value 19.0, homopolymer Tg 69° C., manufactured by Toagosei Co., Ltd.), and acryloylmorpholine (SP value 22.50) as a radically polymerizable compound (C). 9, 38.3 parts of homopolymer Tg 150° C., manufactured by Kojin Co., Ltd., and 1.4 parts of a photopolymerization initiator (trade name: KAYACURE DETX-S, diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd.) were mixed. The mixture was stirred at 50° C. for 1 hour to obtain an active energy ray-curable adhesive (1).

(Production of Polarizing Film A)
After forming a urethane-based easy-adhesive layer having a thickness of 0.5 μm on the acrylic resin film, the active energy ray-curable adhesive (1) was applied to the easy-adhesive layer by an MCD coater (Fuji Machine Co., Ltd.). (Manufactured by the company) (cell shape: honeycomb, gravure roll wire number: 1000/inch, rotation speed 140%/vs line speed), so that the thickness of the adhesive layer was 0.5 μm. Next, the acrylic resin film was bonded to both sides of the polarizer A with a roll machine as the transparent protective film on the viewing side and the panel side via the adhesive (1). Then, both sides of the bonded acrylic resin film were heated to 50° C. by using an IR heater, and both sides were irradiated with the above ultraviolet rays to cure the active energy ray-curable adhesive (1). Further, it was dried with hot air at 70° C. for 3 minutes to obtain a polarizing film A having transparent protective films A on both sides of the polarizer A (Table 1). The bonding line speed was 25 m/min.

<Preparation of adhesive>
(Preparation of polymer solution D)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 89.82 parts of n-butyl acrylate, 8 parts of methyl methacrylate, 1.5 parts of N-vinylpyrrolidone, 0.2 parts of acrylic acid. Part, and a monomer mixture containing 0.48 parts of 4-hydroxybutyl acrylate. Further, with respect to 100 parts of the monomer mixture (solid content), 0.15 parts of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate, and nitrogen gas was introduced while gently stirring. After purging with nitrogen, the liquid temperature in the flask was kept at around 60° C. to carry out a polymerization reaction for 7 hours. Then, ethyl acetate was added to the obtained reaction solution to prepare an acrylic polymer solution D having a weight average molecular weight of 1.3 million and having a solid concentration of 20%.

With respect to 100 parts of the solid content of the prepared acrylic polymer solution D, 0.25 part of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D160N"), a peroxide-based crosslinking agent (manufactured by NOF Corporation, 0.25 parts of trade name "Nyper BMT" and 0.2 parts of acetoacetyl group-containing silane coupling agent (manufactured by Soken Chemical Industry Co., Ltd., trade name "A-100") are blended in this order to prepare adhesive polymer solution D. Was prepared.

(Preparation of polymer solution A)
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of butyl acrylate, 5 parts of acrylic acid, 0.075 parts of 2-hydroxyethyl acrylate and 2,2'-azobisisobutyrate. A solution was prepared by adding 0.3 part of ronitrile together with ethyl acetate. Next, this solution was stirred while blowing nitrogen gas and reacted at 60° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average Mw of 2,200,000. Further, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution A in which the solid content concentration was adjusted to 30%.

As a cross-linking agent, based on 100 parts of the solid content of the acrylic polymer solution A, a cross-linking agent containing 0.6 part of a compound having an isocyanate group as a main component (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") ) And 0.075 part of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”) as a silane coupling agent in this order, and the adhesive agent Polymer solution A was prepared.

(Preparation of polymer solution B)
In a reaction vessel equipped with a cooling tube, a nitrogen introducing tube, a thermometer and a stirrer, 94 parts of 2-ethylhexyl acrylate (2EHA), 6 parts of acrylic acid and 0.3 parts of 2,2′-azobisisobutyronitrile are added. A solution was prepared by adding together with ethyl acetate. Then, the solution was stirred while blowing nitrogen gas and reacted at 60° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight Mw of 2.2 million. Further, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution (B) in which the solid content concentration was adjusted to 30%.

As a cross-linking agent, a cross-linking agent containing 0.6 part of a compound having an isocyanate group as a main component based on 100 parts of the solid content of the acrylic polymer solution (B) (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate") L”) and 0.075 part of γ-glycidoxypropyltrimethoxysilane (trade name “KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent in this order, An adhesive polymer solution B was prepared.

(Preparation of polymer solution C)
In a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirring device, 99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate, and 2,2-azobisisobutyronitrile were used as monomers ( (Solid content) 0.3 part with respect to 100 parts was added together with ethyl acetate and reacted at 60° C. for 4 hours under a nitrogen gas stream, and then ethyl acetate was added to the reaction solution to give an acryl having a weight average molecular weight of 1,650,000. A polymer solution C containing a base polymer was obtained (solid content concentration 30% by weight).

0.3 part of dibenzoyl peroxide (Nippon Yushi Co., Ltd.: Niper BMT) and 0.1 part of trimethylolpropane xylylene diisocyanate (Mitsui Takeda Chemical ( Co., Ltd.: Takenate D110N) and 0.2 part of a silane coupling agent (manufactured by Soken Chemical Industry Co., Ltd.: A-100, acetoacetyl group-containing silane coupling agent) were mixed to prepare an adhesive polymer solution C. .

Composition of acrylic polymer solution (A) (polymer A), acrylic polymer solution (B) (polymer B), acrylic polymer solution (C) (polymer C), and acrylic polymer solution (D) (polymer D) Is shown in Table 2 below.

(Preparation of Silicone Oligomer A)
A 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, a condenser, and a dropping funnel, 100 parts of ethyl acetate, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (2EHMA). 20 parts, polyorganosiloxane skeleton-containing methacrylate monomer having a functional group equivalent of 900 g/mol (trade name: X-22-174ASX, manufactured by Shin-Etsu Chemical Co., Ltd.) 8.7 parts, polyorgano having a functional group equivalent of 4600 g/mol. 11.3 parts of a siloxane skeleton-containing methacrylate monomer (trade name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.2 part of methyl thioglycolate as a chain transfer agent were added. Then, after stirring at 70° C. under a nitrogen atmosphere for 1 hour, 0.2 part of 2,2′-azobisisobutyronitrile was added as a thermal polymerization initiator, and after reacting at 70° C. for 2 hours, As a thermal polymerization initiator, 0.1 part of 2,2′-azobisisobutyronitrile was added, and the reaction was continued at 80° C. for 3 hours. Thus, a solution of silicone oligomer A was obtained. The weight average molecular weight Mw of this silicone oligomer A was 18,000.

(Preparation of other silicone oligomers B to D, E1, E, G)
Silicone oligomers B to D, E1, E and G were produced in the same manner as silicone oligomer A, except that the monomer composition and parts by weight were changed to the constituent components shown in Table 3.

(Preparation of adhesive solution)
The acrylic polymer solution A prepared above was mixed with 1 part of the silicone oligomer A to prepare an acrylic adhesive solution used in Example 1. Similarly, the acrylic polymer solutions used in Examples 2 to 20 were prepared using the adhesive polymer solutions and silicone oligomers shown in Table 4 below.

<Preparation of one-sided protective polarizing film with adhesive layer>
[Example 1] to [Example 20]
The prepared acrylic pressure-sensitive adhesive A is uniformly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone-based release agent, and dried for 1 minute in an air circulation type constant temperature oven at 155° C. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed on each surface. The prepared pressure-sensitive adhesive layer was attached to the polarizer side of the prepared one-sided protective polarizing film B to prepare a one-sided protective polarizing film with an adhesive layer.

[Comparative Example 1]
A polarizing film with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1 except that the silicone oligomer A was removed in Comparative Example 1.

[Comparative Example 2] to [Comparative Example 5]
In Comparative Examples 2 to 5, ether group-containing polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “modified silicone oil KF-353”) or silicone oligomer G was used in place of silicone oligomer A, and the blending amount is shown in Table 4. A polarizing film with an adhesive layer was produced in the same manner as in Example 1 except that the polarizing film was changed as shown.

[Comparative Example 6]
In Comparative Example 6, a polarizing film with an adhesive layer was produced in the same manner as in Example 1 except that the one-side protective polarizing film B was changed to the both-side protective polarizing film A.

The following evaluation was carried out on the pressure-sensitive adhesive layer-attached polarizing films obtained in Examples 1 to 20 and Comparative Examples 1 to 6 above. The results are shown in Table 4.

<Evaluation of durability>
The separator film of the pressure-sensitive adhesive layer-attached polarizing film (15 inches) was peeled off and adhered to a 0.7 mm-thick non-alkali glass (EG-XG, manufactured by Corning Incorporated) using a laminator. Then, autoclave treatment was carried out at 50° C. and 0.5 MPa for 15 minutes to completely adhere the polarizing film to the alkali-free glass. Next, this was put into a heating oven (heating) condition of 80° C., and the presence or absence of peeling of the polarizing plate after 500 hours was evaluated based on the following criteria.
A: No peeling was observed at all.
B: Foaming was recognized to the extent that it could not be visually confirmed.
C: Peeling that could not be visually confirmed was observed.
D: Small bubbles or peeling that can be visually confirmed were observed.
E: Clear foaming or peeling was recognized.

<Evaluation of adhesive strength>
The produced polarizing film with an adhesive layer was cut into a length of 120 mm and a width of 25 mm to obtain a sample. The sample was pressure-bonded to a 0.7 mm-thick non-alkali glass plate (EG-XG manufactured by Corning Co., Ltd.) with a 2 kg roller for one reciprocation, and cured at 23° C. for 1 hour. Further, the sample was heat-pressed with a 2 kg roller for one reciprocation, autoclaved at 50° C. and 5 atm for 15 minutes for complete contact, and then heat-treated in a heating oven at 60° C. for 2 hours and 24 hours to measure the adhesive force. The adhesive force is measured by a tensile tester (Autograph SHIMAZU AG-1 1OKN) at a peeling angle of 90° and a peeling speed of 300 mm/min. (N/25 mm, measuring length 80 mm) I asked for it. The measurement was performed 200 times at intervals of 1 time/0.5 s, and the average value was used as the measured value. The number of samples was three. Then, the reworkability was judged from the adhesive strength evaluation based on the following criteria.
A: 3.5 N/25 mm or less, rework is 90% successful.
B: More than 3.5 N/25 mm and 4 N/25 mm or less, and rework succeeds 80% or more.
C: More than 4 N/25 mm and 5 N/25 mm or less, and rework succeeds 70% or more.
D: More than 5 N/25 mm and 6 N/25 mm or less, and rework succeeds 60% or more.
E: Over 6 N/25 mm, rework fails more than 40%.

<Measuring method of anchoring force of adhesive layer>
A polyethylene terephthalate film [Oike Kogyo Co., Ltd. product name "125 Tetrait OES" (thickness 125 μm)] on which indium tin oxide was vapor-deposited was applied with a 2 kg roller on a 25 mm wide polarizing film with an adhesive layer. After one-way pressure bonding and curing at 23° C. for 1 minute, the adhesive strength was measured when the polyethylene terephthalate film together with the pressure-sensitive adhesive layer was peeled off at 180 mm in the direction of 300 mm/min. Then, the anchoring power was judged according to the following criteria.
A: 15 N/25 mm or more B: 10 N/25 mm or more and 15 N/25 mm or less C: 7.5 N/25 mm or more and 10 N/25 mm or less D: 7.5 N/25 mm or less E: 2 kg Lower than the adhesive strength after roller pressure bonding

As described above, according to the present invention, it is possible to provide a polarizing film with an adhesive layer, which has both high durability and reworkability and is excellent in the adhesiveness (anchoring force) between the polarizing film and the adhesive.

11 Polarizer 12 Protective Film 13 Polarizing Film 14 Adhesive Layer 15 Separator 100 Polarizing Film with Adhesive Layer

Claims

A polarizing film comprising a polarizer and a protective film provided on the viewing side of the polarizer,
A polarizing film with a pressure-sensitive adhesive layer, comprising a pressure-sensitive adhesive layer provided on the side opposite to the viewing side of the polarizer,
The pressure-sensitive adhesive layer includes a base polymer and a silicone oligomer Ps,
The silicone oligomer Ps is included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the base polymer,
The silicone oligomer Ps has a Tg of −50° C. or higher and 100° C. or lower, a side chain silicone functional group equivalent of 1000 to 20000 g/mol, and a weight average molecular weight of 10,000 to 300,000. the film.
The polarized light with the pressure-sensitive adhesive layer according to claim 1, wherein the silicone oligomer Ps contains, as a monomer unit, a monomer S1 having a polyorganosiloxane skeleton and a monomer having a homopolymer glass transition temperature of −70° C. or higher and 180° C. or lower. the film.
3. The base polymer according to claim 1, wherein the base polymer contains 80% by weight or more of an alkyl (meth)acrylate (A) having a glass transition temperature of a homopolymer of −80° C. or higher and 0° C. or lower as a monomer unit. Polarizing film with adhesive layer.
The base polymer further contains, as a monomer unit, at least one polar monomer (B) selected from the group consisting of a carboxyl group-containing monomer (b1) and a nitrogen-containing monomer (b2) in an amount of 5% by weight or less. The polarizing film with a pressure-sensitive adhesive layer according to claim 3, which is characterized in that.
The base polymer further contains, as monomer units, 0.1 to 18% by weight of an alkyl methacrylate having a glass transition temperature of a homopolymer of 0 to 180° C. and 0 to 5% by weight of a hydroxyl group-containing monomer. The polarizing film with a pressure-sensitive adhesive layer according to claim 4, wherein
The polarizing film with an adhesive layer according to any one of claims 1 to 5, wherein the base polymer has a weight average molecular weight of 500,000 to 2,500,000.
The polarizing film with an adhesive layer according to any one of claims 1 to 6, wherein the thickness of the polarizer is more than 0 μm and 12 μm or less.
The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 7, wherein a melting temperature of the silicone oligomer Ps is -20°C to 120°C.