CN113242987A

CN113242987A - Polarizing film with adhesive layer

Info

Publication number: CN113242987A
Application number: CN201980081788.4A
Authority: CN
Inventors: 森本有; 外山雄祐; 仲野武史
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2018-12-14
Filing date: 2019-12-11
Publication date: 2021-08-10
Anticipated expiration: 2039-12-11
Also published as: CN113196117B; WO2020122147A1; CN113167964B; CN113167964A; TW202031852A; TWI827766B; KR20210102186A; CN113242987B; CN117518328A; KR20210102185A; TWI827765B; TWI825244B; TW202033713A; KR20210102187A; CN113196117A; WO2020122146A1; TW202037695A; WO2020122148A1

Abstract

The invention provides a thin polarizing film with an adhesive layer, which has high durability and reworkability and has excellent adhesion (anchoring force) between the polarizing film and the adhesive. The thin polarizing film with an adhesive layer comprises a polarizing film having a polarizer and a protective film provided on the viewing side of the polarizer, and an adhesive layer provided on the side opposite to the viewing side of the polarizer, wherein the adhesive layer comprises 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 based on 100 parts by weight of the base polymer, the silicone oligomer Ps has a Tg of-50 ℃ or higher and 100 ℃ or lower, a silicone functional group equivalent of a side chain is 1000 to 20000g/mol, and a weight average molecular weight is 10000 or higher and 300000 or lower.

Description

Polarizing film with adhesive layer

Technical Field

The present invention relates to a polarizing film with an adhesive layer. More specifically, the present invention relates to a thin polarizing film with an adhesive layer, which has a protective film on one side of a polarizer.

Background

In a liquid crystal display device, it is essential to dispose polarizing films on both sides of a glass substrate forming a surface of a liquid crystal panel in view of an image forming method. As the polarizing film, a polarizing film obtained by laminating a protective film on one or both surfaces of a polarizer made of a dichroic material such as iodine and a polyvinyl alcohol-based film with a polyvinyl alcohol-based adhesive or the like is generally used.

When the polarizing film is bonded to a liquid crystal cell or the like, an adhesive is generally used. In addition, since there are advantages in that the polarizing film can be instantaneously fixed, a drying process for fixing the polarizing film is not required, and the like, the adhesive may be previously provided on one surface of the polarizing film in the form of an adhesive layer. That is, in the lamination of a polarizing film, a polarizing film with an adhesive layer is generally used (patent documents 1 and 2).

In addition, when a polarizing film or a polarizing film with an adhesive layer is bonded to a glass substrate of a liquid crystal panel, durability is required, and for example, in a durability test using heating, humidification, or the like, which is generally performed as an environmental promotion test, it is required that defects such as peeling or lifting of the adhesive layer do not occur.

The pressure-sensitive adhesive used for the polarizing film is required to have high durability, and the demand for reworkability is also high in order to correct defects and attachment errors caused by the process defects in the lamination of the polarizing plate. In recent years, polarizing plates having a thin polarizer and a protective film only on one side of the polarizer have been widely used. Such a thin polarizing plate has a small dimensional change after heating and is likely to have high durability, while the polarizing film has a small layer thickness, and therefore, in actuality, the polarizing plate is likely to be broken during reworking, and the reworking obstacle is increased. The re-operability is an important item, but the high durability and the re-operability are in a trade-off relationship, and are characteristics that are very difficult to be compatible.

Further, when the adhesiveness between the polarizing film and the pressure-sensitive adhesive layer is poor, a problem occurs in that only the pressure-sensitive adhesive remains on the panel during the rework. In addition, when a polarizing film in a roll shape is subjected to a process such as punching, paste defects may occur to affect visibility, and adhesion (anchoring force) between the polarizing film and an adhesive is also an important characteristic.

In addition, since the thin polarizing plate described above has a protective film only on one side of the polarizer, a conductive coating layer (anchor coat layer) is applied to the polarizer as it is, that is, without interposing a protective film therebetween, according to a conventional method. However, the thin polarizing plate described above is weak against external stress. Further, if the iodine is directly applied to the polarizer without interposing a protective film therebetween, iodine in the polarizer is easily discolored. Therefore, the conductive coating (anchor coat) cannot be directly provided on the polarizer by the conventional method.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-

Patent document 2: japanese patent laid-open No. 2018-169612

Disclosure of Invention

Problems to be solved by the invention

In view of the background described above, a thin polarizing film with an adhesive layer, which can have both high durability and reworkability in a trade-off relationship and has excellent adhesion (anchoring force) between the polarizing film and the adhesive, is strongly desired.

Means for solving the problems

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

That is, the present invention includes the following embodiments.

(1) A polarizing film with an adhesive layer, comprising:

a polarizing film having a polarizer and a protective film provided on a viewing side of the polarizer; and

an adhesive layer provided on the side of the polarizer opposite to the visible side,

wherein the adhesive layer contains a base polymer and a silicone oligomer Ps, and the silicone oligomer Ps is contained 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 ℃ to 100 ℃, a side chain silicone functional group equivalent of 1000 to 20000g/mol, and a weight average molecular weight of 10000 to 300000.

(2) The adhesive layer-equipped polarizing film according to the above (1),

the silicone oligomer Ps contains a monomer having a polyorganosiloxane skeleton and a monomer having a homopolymer glass transition temperature of-70 ℃ or higher and 180 ℃ or lower as monomer units.

(3) The adhesive layer-equipped polarizing film according to the above (1) or (2),

the base polymer contains, as monomer units, at least 80% by weight of a homopolymer of an alkyl (meth) acrylate (A) having a glass transition temperature of-80 ℃ to 0 ℃.

(4) The adhesive layer-equipped polarizing film according to the above (3),

the base polymer further contains at least one polar monomer (B) selected from a carboxyl group-containing monomer (B1) and a nitrogen-containing monomer (B2) as a monomer unit in an amount of 5% by weight or less.

(5) The adhesive layer-equipped polarizing film according to the above (4),

the base polymer further contains 0.1 to 18 wt% of an alkyl methacrylate having a glass transition temperature of a homopolymer of 0 ℃ to 180 ℃ and 0 to 5 wt% of a hydroxyl group-containing monomer as a monomer unit.

(6) The adhesive-layer-equipped polarizing film according to any one of the above (1) to (5),

the weight average molecular weight of the base polymer is 50 to 250 ten thousand.

(7) The adhesive-layer-equipped polarizing film according to any one of the above (1) to (6),

the thickness of the polarizer is more than 0 μm and not more than 12 μm.

(8) The adhesive-layer-equipped polarizing film according to any one of the above (1) to (7),

the melting temperature of the organic silicon oligomer Ps is-20 ℃ to 120 ℃.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a thin polarizing film with an adhesive layer can be provided which can provide reworkability immediately after lamination, can provide durability by increasing adhesive strength after heating, and has excellent adhesion (anchoring force) between the polarizing film and the adhesive.

Drawings

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

Description of the symbols

11 polarizer

12 protective film

13 polarizing film

14 adhesive layer

15 diaphragm

100 polarizing film with adhesive layer

Detailed Description

Preferred embodiments of the present invention will be described below. The person skilled in the art can understand matters necessary for the practice of the present invention other than the matters specifically described in the present specification based on the teaching about the practice of the invention described in the present specification and the technical common sense at the time of application. The present invention can be implemented based on the contents disclosed in the present specification and the common general knowledge in the art.

< polarizing film with adhesive layer >

The polarizing film with an adhesive layer of the present invention includes a polarizing film and an adhesive layer. In the present invention, the adhesive layer may be present on one side or both sides of the polarizing film.

The structure of an adhesive layer-attached polarizing film of one embodiment is schematically shown in fig. 1. 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 a pressure-sensitive adhesive layer 14 provided on one surface thereof. In fig. 1, a 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 of the polarizing film 13 opposite to the viewing side of the polarizer 11 so as to be fixed without interposing a protective film therebetween, that is, so as not to separate the pressure-sensitive adhesive layer 14 from the polarizing film 13. 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 separator configured such that a release layer formed of a release treatment agent is provided on one surface of a sheet-like base material (backing material) and the one surface is a release surface can be preferably used. The structure of the polarizing film with an adhesive layer is not limited to the embodiment schematically illustrated in fig. 1.

< polarizer >

The polarizer is not particularly limited, and various polarizers can be used. Examples of the polarizer include films obtained by uniaxially stretching hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene-vinyl acetate copolymer partially saponified films, and polyene oriented films such as polyvinyl alcohol dehydrated products and polyvinyl chloride desalted products, and the like. Among these, a polarizer made of a dichroic material such as a polyvinyl alcohol film and iodine is preferable. The thickness of these polarizers is not particularly limited, but is usually 2 to 25 μm. In one embodiment of the present invention, the thickness of the polarizer may exceed 0 μm and be 12 μm or less, preferably 1 μm to 10 μm, and more preferably 2 μm to 7 μm.

The polarizer obtained by uniaxially stretching a polyvinyl alcohol film dyed with iodine can be produced, for example, by dyeing a polyvinyl alcohol film by immersing the film in an aqueous iodine solution and stretching the film to 3 to 7 times the original length. The coating composition may be immersed in an aqueous solution of potassium iodide or the like optionally containing boric acid, zinc sulfate, zinc chloride or the like as necessary. Further, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing, if necessary. By washing the polyvinyl alcohol film with water, dirt and an anti-blocking agent on the surface of the polyvinyl alcohol film can be washed off, and the polyvinyl alcohol film can be swollen to prevent unevenness such as uneven dyeing. The stretching may be performed after the dyeing with iodine, or may be performed while dyeing, or may be performed after the stretching with iodine. Stretching may be carried out in an aqueous solution or water bath of boric acid, potassium iodide, or the like.

< protective film >

The material constituting the protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like. Examples thereof include: polyester polymers such AS polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such AS cellulose diacetate and cellulose triacetate, acrylic polymers such AS polymethyl methacrylate, styrene polymers such AS polystyrene and acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. Examples of the polymer forming the protective film include: examples of the polymer include polyolefin polymers such as polyethylene, polypropylene, cyclic polyolefins having a norbornene structure, and ethylene-propylene copolymers, amide polymers such as vinyl chloride polymers, nylon and aromatic polyamides, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, aromatic ester polymers, polyoxymethylene polymers, epoxy polymers, and mixtures thereof. These protective films are generally bonded to the polarizer with an adhesive layer. In addition, the protective film may be formed as follows: a thermosetting resin or an ultraviolet curable resin such as a (meth) acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin, or a silicone resin is applied to a polarizer and then cured.

The protective film may contain one or more kinds of any appropriate additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more 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 wt% or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, or the like can be used. Examples of the retardation film include a retardation film having a front retardation of 40nm or more and/or a thickness direction retardation of 80nm or more. The front phase difference is usually controlled within a range of 40 to 200nm, and the thickness direction phase difference is usually controlled within a range of 80 to 300 nm. When the retardation film is used as the protective film, the retardation film also functions as a polarizer protective film, and therefore, the thickness can be reduced.

Examples of the retardation film include a birefringent film obtained by subjecting a thermoplastic resin film to a uniaxial stretching treatment or a biaxial stretching treatment. The temperature and stretch ratio of the stretching can be appropriately set depending on the retardation value, the material and thickness of the film.

The thickness of the protective film may be suitably determined, and is preferably 3 to 200 μm, more preferably 3 to 100 μm, in general, from the viewpoints of strength, handling properties such as handling properties, and thin layer properties. Particularly, the thickness of the protective film (in the case of a film formed in advance) is preferably 10 to 60 μm, and 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, and more preferably 3 to 20 μm, from the viewpoint of transportability. The protective film may be used in a plurality of or a plurality of layers.

A functional layer such as a hard coat layer, an antireflection layer, an adhesion prevention layer, a diffusion layer, or an antiglare layer may be provided on the surface of the protective film that is not bonded to the polarizer. The functional layers such as the hard coat layer, the antireflection layer, the adhesion prevention layer, the diffusion layer, and the antiglare layer may be provided as the protective film itself, or may be provided separately from the protective film.

< sandwiching layer >

The protective film and the polarizer may be laminated with an interlayer such as an adhesive layer, and an undercoat layer (primer layer) interposed therebetween. In this case, it is preferable to stack both layers without an air gap by using an interlayer.

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

Examples of the aqueous adhesive include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and aqueous polyesters. The aqueous adhesive is generally used in the form of an aqueous adhesive, 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 an active energy ray such as an electron beam or ultraviolet ray (radical-curable type or cation-curable type), and can be used in the form of, for example, an electron beam-curable type or an ultraviolet-curable type. As the active energy ray-curable adhesive, for example, a radical photo-curable adhesive can be used. When a radical photo-curable active energy ray-curable adhesive is used as the ultraviolet-curable adhesive, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

When an aqueous adhesive or the like is used for the application of the adhesive, the adhesive layer to be finally formed is preferably made to have 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, the thickness of the adhesive layer is preferably set to 0.1 to 200 μm. More preferably 0.5 to 50 μm, and still more preferably 0.5 to 10 μm.

In the case of laminating the polarizer and the protective film, an easy adhesion layer may be provided between the protective film and the adhesive layer.

< adhesive layer >

In the present invention, the adhesive layer used contains a base polymer, and a silicone oligomer Ps.

The pressure-sensitive adhesive used in the present invention for constituting the pressure-sensitive adhesive layer is not particularly limited, and a rubber-based pressure-sensitive adhesive, an acrylic-based 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, a polyvinyl pyrrolidone-based pressure-sensitive adhesive, a polyacrylamide-based pressure-sensitive adhesive, a cellulose-based pressure-sensitive adhesive, and the like can be used. Various base polymers may be used depending on the binder used.

Among the above-mentioned pressure-sensitive adhesives, those excellent in optical transparency, exhibiting suitable adhesive properties such as wettability, cohesiveness and adhesiveness, and excellent in weather resistance, heat resistance and the like can be preferably used. As the adhesive exhibiting such characteristics, an acrylic adhesive can be preferably used. As the base polymer of the acrylic adhesive, a (meth) acrylic polymer is used. It is to be noted that the (meth) acrylate includes acrylate and/or methacrylate.

< basic Polymer >

In the present invention, as the base polymer, a (meth) acrylic polymer is generally used.

(1) Alkyl (meth) acrylate (A)

The (meth) acrylic polymer usually contains an alkyl (meth) acrylate as a main component as a monomer unit. As the alkyl (meth) acrylate (A) constituting the main skeleton of the (meth) acrylic polymer, a linear or branched alkyl (meth) acrylate having from C1 to C20 may be used. Examples of the alkyl (meth) acrylate having C1 to C20 include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (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, dodecyl (meth) acrylate, and the like, Pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like, but the present invention is not limited thereto. These alkyl (meth) acrylates may 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 alkyl (meth) acrylates that can be preferably used as monomer units of the (meth) acrylic polymer include methyl acrylate, Methyl Methacrylate (MMA), n-Butyl Methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), and the like.

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

In one embodiment of the present invention, the alkyl (meth) acrylate (a) used as a monomer unit of the base polymer may 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, the alkyl (meth) acrylate (a) having a glass transition temperature of a homopolymer of-80 ℃ to 0 ℃ may be contained in an amount of 80% by weight or more as a monomer unit of the base polymer.

In one embodiment of the present invention, the base polymer preferably further contains, as a monomer unit, an alkyl methacrylate whose homopolymer has a glass transition temperature of 0 ℃ or more and 180 ℃ or less. The alkyl methacrylate having a glass transition temperature of 0 ℃ to 180 ℃ of the homopolymer is contained in an amount of more preferably 1 to 15% by weight, still more preferably 2.5 to 10% by weight, and still more preferably 4% by weight or more and less than 10% by weight of the base polymer.

Examples of the alkyl methacrylate having a homopolymer glass transition temperature of 0 ℃ to 180 ℃ include linear alkyl (meth) acrylates such as methyl acrylate (Tg: 8 ℃), methyl methacrylate (Tg: 105 ℃), ethyl methacrylate (Tg: 65 ℃), n-propyl acrylate (Tg: 3 ℃), n-propyl methacrylate (Tg: 35 ℃), n-pentyl acrylate (Tg: 22 ℃), n-tetradecyl acrylate (Tg: 24 ℃), n-hexadecyl acrylate (Tg: 35 ℃), n-hexadecyl methacrylate (Tg: 15 ℃), n-octadecyl acrylate (Tg: 30 ℃), and n-octadecyl methacrylate (Tg: 38 ℃); branched alkyl (meth) acrylates such as t-butyl acrylate (Tg: 43 ℃ C.), t-butyl methacrylate (Tg: 48 ℃ C.), isopropyl methacrylate (Tg: 81 ℃ C.), and isobutyl methacrylate (Tg: 48 ℃ C.); and cyclic alkyl (meth) acrylates such as cyclohexyl acrylate (Tg: 19 ℃ C.), cyclohexyl methacrylate (Tg: 65 ℃ C.), isobornyl acrylate (Tg: 94 ℃ C.), and isobornyl methacrylate (Tg: 180 ℃ C.). These alkyl methacrylates may be used alone or in combination. Among these, at least one selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl acrylate, and isobornyl methacrylate is preferably used, and at least one selected from the group consisting of methyl acrylate, methyl methacrylate, and isobornyl acrylate is more preferably used.

In one embodiment of the present invention, the (meth) acrylic polymer as the base polymer may contain a hydroxyl group-containing monomer as a monomer unit in an amount of 0 to 5% by weight with respect to the polarizing film having an adhesive layer. The hydroxyl group-containing monomer is contained in an amount of more preferably 0.01 to 1% by weight, and still 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: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate, but the present invention is not limited thereto. In a preferred embodiment of the present invention, the hydroxyl group-containing monomer may be 4-hydroxybutyl acrylate (4-HBA) or 2-hydroxybutyl acrylate (2-HBA).

In a preferred embodiment of the present invention, the base polymer may further contain 0.1 to 18% by weight of an alkyl methacrylate having a homopolymer glass transition temperature of 0 ℃ or more and 180 ℃ or less and 0 to 5% by weight of a hydroxyl group-containing monomer as a monomer unit.

In one embodiment of the present invention, the (meth) acrylic polymer may further contain, as necessary, another monomer (copolymerizable monomer) copolymerizable with the alkyl (meth) acrylate, in addition to the alkyl (meth) acrylate (a) as a main component. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxyl group, a nitrogen atom-containing ring, or the like) can be suitably used. The monomer having a polar group can contribute to introduction of a crosslinking point into the acrylic polymer and increase the cohesive force of the (meth) acrylic polymer. The copolymerizable monomer may be used alone or in combination of two or more.

Non-limiting examples of copolymerizable monomers include: carboxyl group-containing monomers, acid anhydride group-containing monomers, sulfonic acid group-or phosphoric acid group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, nitrogen atom-containing ring-containing monomers, succinimide skeleton-containing monomers, maleimides, itaconimides, aminoalkyl (meth) acrylates, alkoxyalkyl (meth) acrylates, vinyl esters, vinyl ethers, aromatic vinyl compounds, olefins, (meth) acrylates having alicyclic hydrocarbon groups, (meth) acrylates having aromatic hydrocarbon groups, and heterocycle-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylates, halogen atom-containing (meth) acrylates such as vinyl chloride and fluorine atom-containing (meth) acrylates, silicon atom-containing (meth) acrylates such as organosilicon (meth) acrylates, and the like, (meth) acrylic acid esters obtained from alcohols which are terpene compound derivatives, and the like.

Examples of the carboxyl group-containing monomer include: acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, methacrylic acid, etc.;

examples of the acid anhydride group-containing monomer include: maleic anhydride, itaconic anhydride;

examples of the sulfonic acid group-or phosphoric acid group-containing monomer include: styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide-propanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloyl phosphate, and the like;

examples of the epoxy group-containing monomer include: epoxy group-containing acrylates such as glycidyl (meth) acrylate and 2-ethyl glycidyl (meth) acrylate, allyl glycidyl ether, glycidyl ether of (meth) acrylate, and the like;

examples of the cyano group-containing monomer include: acrylonitrile, methacrylonitrile, and the like;

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-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dipropyl (meth) acrylamide, N-diisopropyl (meth) acrylamide, N-di-N-butyl (meth) acrylamide, and N, N-di-t-butyl (meth) acrylamide; n-alkyl (meth) acrylamides such as N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-N-butyl (meth) acrylamide; n-vinylcarboxylic acid amides such as N-vinylacetamide; and N, N-dimethylaminopropyl (meth) acrylamide, hydroxyethylacrylamide, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylolpropyl (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

Oxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholine, N-vinyl-2-caprolactam, N-vinyl-1, 3-

Oxazin-2-ones, N-vinyl-3, 5-morpholino-diones, N-vinylpyrazoles, N-vinylisoxazines

Oxazoles, N-vinylthiazoles, N-vinylisothiazoles, N-vinylpyridazines, and the like (for example, lactams such as N-vinyl-2-caprolactam);

examples of the monomer having a succinimide skeleton include: n- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxohexamethylene succinimide, N- (meth) acryloyl-8-oxohexamethylene succinimide, etc.;

as the maleimide group, for example: n-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, etc.;

examples of the itaconimides include: n-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexyl itaconimide, N-cyclohexylitaconimide, N-lauryl itaconimide, etc.;

examples of aminoalkyl (meth) acrylates include: aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, N-diethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate;

examples of alkoxyalkyl (meth) acrylates include: methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, and the like;

examples of the vinyl esters include: vinyl acetate, vinyl propionate, and the like;

examples of the vinyl ethers include: vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether;

examples of the aromatic vinyl compound include: styrene, alpha-methylstyrene, vinyltoluene, etc.;

examples of olefins include: ethylene, butadiene, isoprene, isobutylene, etc.;

examples of the (meth) acrylate 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) acrylate having an aromatic hydrocarbon group include: phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, and the like.

When such a copolymerizable monomer is used, the amount thereof is not particularly limited, and is usually preferably 0.01% by weight or more based on the total amount of the monomer components. From the viewpoint of more effectively exhibiting the effects of the use of the copolymerizable monomer, the amount of the copolymerizable monomer to be used may be 0.1% by weight or more, or may be 1% by weight or more, based on the total amount of the monomer components. The amount of the copolymerizable monomer used may be 50% by weight or less, preferably 40% by weight or less, based on the total amount of the monomer components. This prevents the cohesive force of the adhesive from becoming too high, and improves the sticky feeling at room temperature (25 ℃).

In one embodiment of the present invention, the (meth) acrylic polymer may contain, as a monomer unit, a hydroxyl group-containing monomer (typically, a hydroxyl group-containing (meth) acrylic monomer) as described above, in addition to the alkyl (meth) acrylate as a main component. As the hydroxyl group-containing monomer, as described above, there can be mentioned, for example: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and 4-hydroxymethylcyclohexyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate can be suitably used. Preferred examples of the above are 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4 HBA). By using the hydroxyl group-containing monomer, the cohesive force and polarity of the adhesive can be adjusted, and the adhesive force after heating can be improved. In addition, the hydroxyl group-containing monomer can also contribute to suppression of deterioration in transparency due to moisture by increasing the hydrophilicity of the adhesive layer. When the hydroxyl group-containing monomer is contained, the amount of the hydroxyl group-containing monomer to be used is not particularly limited, and may be, for example, usually 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, or the like, based on the total amount of the monomer units used for producing the (meth) acrylic polymer.

In one embodiment of the present invention, the (meth) acrylic polymer may contain a polyfunctional monomer, if necessary, in addition to the alkyl (meth) acrylate as a main component for the purpose of adjusting the cohesive force of the pressure-sensitive adhesive layer. 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 tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolpropane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butylene glycol (meth) acrylate, styrene oxide, or mixtures thereof, Hexanediol di (meth) acrylate, and the like. Of these, trimethylolpropane tri (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate can be suitably used. The polyfunctional monomer 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, and the like, and is usually suitably in the range of 0.01 to 3.0% by weight, and may be 0.02 to 2.0% by weight, or 0.03 to 1.0% by weight, based on the total amount of the monomer components used for producing the alkyl (meth) acrylate (a).

(2) Polar monomer (B)

In one embodiment of the present invention, the base polymer may further contain at least one polar monomer (B) selected from the carboxyl group-containing monomer (B1) and the nitrogen-containing monomer (B2) as a copolymerizable monomer unit.

In one embodiment of the present invention, the polar monomer (B) may be contained 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 carboxyl group-containing monomer (b1) include: acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, methacrylic acid, and the like, but are not limited thereto. 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 contain a nitrogen-containing monomer (b2) as a copolymerizable monomer unit. Examples of the nitrogen-containing monomer (b2) include: vinyl monomers having a lactam ring (e.g., vinyl pyrrolidone monomers such as N-vinyl pyrrolidone and methyl vinyl pyrrolidone, and vinyl lactam monomers having a lactam ring such as a β -lactam ring, a δ -lactam ring, and an e-lactam ring); maleimide monomers such as maleimide, N-cyclohexylmaleimide and N-phenylmaleimide; (N-substituted) amide monomers such as (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropyl (meth) acrylamide; aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylateAminoalkyl (meth) acrylate monomers such as esters and 3- (3-pyridyl) propyl (meth) acrylate; succinimide monomers such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, and N- (meth) acryloyl-8-oxyoctamethylene succinimide; cyano (meth) acrylate monomers such as acrylonitrile and methacrylonitrile; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinylpyridine

Oxazole, vinyl morpholine, N-vinyl carboxylic 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-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 polymerization methods known as a method for synthesizing an acrylic polymer, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be suitably used. Among several ways, solution polymerization may be preferably employed. The polymerization temperature in the solution polymerization may be appropriately selected depending on the kind of the monomer and the solvent used, the kind of the polymerization initiator, and the like, and may be, for example, about 20 to 170 ℃ (typically about 40 to 140 ℃).

The initiator used for polymerization may be suitably selected from conventionally known thermal polymerization initiators, photopolymerization initiators and the like according to the polymerization method. The polymerization initiator may be used singly or in combination of two or more.

Examples of the thermal polymerization initiator include: azo polymerization initiators (e.g., 2,2 ' -azobisisobutyronitrile, 2,2 ' -azobis (2-methylbutyronitrile), dimethyl 2,2 ' -azobis (2-methylpropionate), 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 ' -dimethyleneisobutyramidine) dihydrochloride, etc.); persulfates such as potassium persulfate; peroxide-based polymerization initiators (e.g., dibenzoyl peroxide, t-butyl peroxymaleate, lauroyl peroxide, etc.); redox polymerization initiators, and the like. The amount of the thermal polymerization initiator to be used is not particularly limited, and may be, for example, in the range of 0.01 to 5 parts by weight, and preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the monomer component used for the production of the acrylic polymer.

The photopolymerization initiator is not particularly limited, and for example: benzoin ether type photopolymerization initiator, acetophenone type photopolymerization initiator, α -alcohol ketone type photopolymerization initiator, aromatic sulfonyl chloride type photopolymerization initiator, photoactive oxime type photopolymerization initiator, benzoin type photopolymerization initiator, benzil type photopolymerization initiator, benzophenone type photopolymerization initiator, ketal type photopolymerization initiator, thioxanthone type photopolymerization initiator, acylphosphine oxide type photopolymerization initiator, and the like. The amount of the photopolymerization initiator used is not particularly limited, and may be, for example, in the range of 0.01 to 5 parts by weight, and preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the monomer component used for the production of the acrylic polymer.

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

In the present invention, the weight average molecular weight Mw of the base polymer may be 50 to 250 ten thousand. In one embodiment of the present invention, the weight average molecular weight Mw of the base polymer is preferably from 70 to 270 ten thousand, and more preferably may be from 80 to 250 ten thousand.

< Silicone oligomer Ps >

In the present invention, the adhesive layer contains the silicone oligomer Ps. The silicone oligomer Ps functions as an adhesive force increase retarder by virtue of the low polarity and mobility of the siloxane structure, and contributes to suppression of initial adhesive force and improvement of the adhesive force increase ratio. As the silicone oligomer Ps, a polymer having a siloxane structure in a side chain can be preferably used.

In the present invention, the glass transition temperature (Tg) of the silicone oligomer Ps used is in the range of-50 ℃ to 100 ℃. In one embodiment of the present invention, the Tg of the silicone oligomer Ps is preferably-30 ℃ or higher and 70 ℃ or lower, and more preferably may be-20 ℃ or higher and 60 ℃ or lower. When the Tg of the silicone oligomer Ps is within the above range, the initial low adhesiveness and the increase in adhesive force during use (strong adhesiveness) can be achieved at a high level.

In the present invention, the weight average molecular weight Mw of the silicone oligomer Ps used is in the range of 10000 to 300000. In one embodiment of the present invention, the weight average molecular weight Mw of the silicone oligomer Ps is preferably 12500 or more and 2500000 or less, and more preferably may be 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 the mobility in the pressure-sensitive adhesive layer within an appropriate range, and it is easy to realize a pressure-sensitive adhesive sheet that has both the initial low adhesiveness and the strong adhesiveness in use at a high level.

In a preferred embodiment of the present invention, the silicone oligomer Ps has a Tg of-50 ℃ or higher and 100 ℃ or lower, a side chain silicone functional group equivalent of 1000 to 20000g/mol, and a weight average molecular weight Mw of 10000 or higher and 300000 or lower.

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

(1) Monomer S1 having a polyorganosiloxane skeleton

The monomer S1 having a polyorganosiloxane skeleton, which can be used for 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: trimethylsiloxane (TM), Dimethylsiloxane (DM), polyoxyethylmethylsiloxane (EOM), etc., but is not limited thereto.

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, X-22-174ASX, X-22-2426, X-22-2475, KF-2012, X-22-174BX, X-22-2404, and the like, which are single-terminal reactive silicone oils manufactured by shin-Etsu chemical industries, Ltd. The monomer S1 having a polyorganosiloxane skeleton may be used singly or in combination of two or more.

[ chemical formula 1]

[ chemical formula 2]

Wherein R in the above general formulae (1) and (2)³Is hydrogen or methyl, R⁴Is methyl or a 1-valent organic group, and m and n are integers of 0 or more.

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

Here, the "functional group equivalent" means the weight of the main skeleton (for example, polydimethylsiloxane) bonded with 1 functional group on average. The labeling unit g/mol was converted to 1mol of a functional group. The functional group equivalent of the monomer S1 having a polyorganosiloxane skeleton can be based on Nuclear Magnetic Resonance (NMR) and according to¹The spectral intensity of H-NMR (proton NMR) was calculated. Based on¹The calculation of the functional group equivalent (g/mol) of the monomer S1 having a polyorganosiloxane skeleton of the spectral intensity of H-NMR can be based on¹A general structural analysis method of H-NMR spectroscopy is described in Japanese patent No. 5951153, if necessary.

When two or more 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, n kinds of monomers having different functional group equivalents (monomer S1) can be calculated by the following formula₁Monomer S1₂Monomer S1_n) Functional group equivalent of the constituent monomer S1.

Functional group equivalent (g/mol) of monomer S1 ═ monomer S1₁Functional group equivalent of (2) monomer S1₁The amount of (3) + monomer S1₂Functional group equivalent of (2) monomer S1₂The mixing amount of (A) is + monomer S1_nFunctional group equivalent of (2) monomer S1_n(iii) compounding amount)/(monomer S1₁The amount of (3) + monomer S1₂The mixing amount of (A) is + monomer S1_nThe amount of the composition

The content of the monomer S1 having a polyorganosiloxane skeleton relative to the total monomer components used for preparing the silicone oligomer Ps may be, for example, 5% by weight or more, and is preferably 10% by weight or more, and may be 15% by weight or more, from the viewpoint of better exerting the effect as a retardation agent for increasing the adhesive strength. 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 preferably 60% by weight or less, may be 50% by weight or less, may be 40% by weight or less, and may be 30% by weight or less, based on the total monomer components used for preparing the silicone oligomer Ps. When the content of the monomer S1 having a polyorganosiloxane skeleton is within the above range, a psa sheet can be easily realized that has both initial low tackiness and an increase in adhesive strength during use (strong tackiness) at a high level.

(2) A homopolymer having a glass transition temperature of-70 ℃ to 180 ℃ inclusive

The silicone oligomer Ps of the present invention contains a (meth) acrylic monomer or other copolymerizable monomer copolymerizable with the monomer S1 having a polyorganosiloxane skeleton. As the copolymerizable (meth) acrylic monomer or other copolymerizable monomer that can be used in the silicone oligomer Ps of the present invention, monomers having a homopolymer glass transition temperature of-70 ℃ or higher and 180 ℃ or lower can be used, and examples thereof include: alkyl (meth) acrylates, and (meth) acrylates having alicyclic hydrocarbon groups, but are not limited thereto. Examples of the alkyl (meth) acrylate include Methyl Methacrylate (MMA), Butyl Methacrylate (BMA), 2-ethylhexyl methacrylate (2-EHMA), Butyl Acrylate (BA), and 2-ethylhexyl acrylate (2-EHA), and examples of the (meth) acrylate having an alicyclic hydrocarbon group include, but are not limited to, 2- ((3-hydroxymethyl) adamantan-1-yl) methoxy-2-oxoethyl methacrylate (2EHAMA), cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and 1-adamantyl (meth) acrylate. In one embodiment of the present invention, at least one monomer unit selected from the group consisting of 2- ((3-hydroxymethyl) adamantan-1-yl) methoxy-2-oxoethyl methacrylate (2EHAMA) and isobornyl methacrylate (IBXMA) may be contained. In another embodiment of the present invention, at least one monomer unit selected from the group consisting of dicyclopentyl methacrylate, isobornyl methacrylate, and cyclohexyl methacrylate may be contained. These monomers may be used singly or in combination of two or more.

The amount of the alkyl (meth) acrylate and the (meth) acrylate having an alicyclic hydrocarbon group used may be, for example, 10 wt% or more and 95 wt% or less, 20 wt% or more and 95 wt% or less, 30 wt% or more and 90 wt% or less, 40 wt% or more and 90 wt% or less, or 50 wt% or more and 85 wt% or less based on the total monomer components used to prepare the silicone oligomer Ps.

Examples of the monomer that can be contained together with the monomer S1 as a monomer unit constituting the silicone oligomer Ps include the carboxyl group-containing monomer, the acid anhydride group-containing monomer, the hydroxyl group-containing monomer, the epoxy group-containing monomer, the cyano group-containing monomer, the isocyanate group-containing monomer, the amide group-containing monomer, the monomer having a nitrogen atom-containing ring, the monomer having a succinimide skeleton, the maleimides, the itaconimides, the aminoalkyl (meth) acrylates, the vinyl esters, the vinyl ethers, the olefins, the (meth) acrylates having an aromatic hydrocarbon group, the heterocyclic ring-containing (meth) acrylates, the halogen atom-containing (meth) acrylates, and the (meth) acrylates obtained from terpene compound derivative alcohols described above.

Examples of the monomer that can be contained together with the monomer S1 as a monomer unit constituting the silicone oligomer Ps include oxyalkylene di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate; a monomer having a polyoxyalkylene skeleton, for example, a polymerizable polyoxyalkylene ether having a polymerizable functional group such as a (meth) acryloyl group, vinyl group, or allyl group at one end of a polyoxyalkylene chain and having an ether structure (alkyl ether, aryl ether, arylalkyl ether, or the like) at the other end, such as polyethylene glycol or polypropylene glycol; methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylateAlkoxyalkyl (meth) acrylates such as propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and ethoxypropyl (meth) acrylate; salts such as alkali metal (meth) acrylate; polyvalent (meth) acrylates such as trimethylolpropane tri (meth) acrylate: halogenated vinyl compounds such as vinylidene chloride and 2-chloroethyl (meth) acrylate; 2-vinyl-2-

Oxazoline, 2-vinyl-5-methyl-2-

Oxazoline, 2-isopropenyl-2-

Oxazoline or the like

An oxazoline-based monomer; aziridinyl group-containing monomers such as (meth) acryloyl aziridine and 2-aziridinylethyl (meth) acrylate; hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and adducts of lactones and 2-hydroxyethyl (meth) acrylate; fluorine-containing vinyl monomers such as fluorine-substituted alkyl (meth) acrylates; reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and monochloroacetic acid vinyl ester; silicone-containing vinyl monomers such as vinyltrimethoxysilane, gamma- (meth) acryloyloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, and 2-methoxyethoxy-trimethoxysilane; and macromonomers having a radical polymerizable vinyl group at the terminal of a monomer obtained by polymerizing a vinyl group. These monomers may be used alone or in combination and copolymerized with the monomer S1.

In the embodiment in which the monomer component used for the production of the silicone oligomer Ps contains 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 may be 50% by weight or more, 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, for example.

The composition of the (meth) acrylic monomer contained in the monomer component may be, for example, the glass transition temperature T based on the composition of the (meth) acrylic monomer_m1Set above 0 ℃. Here, the glass transition temperature T based on the composition of the (meth) acrylic monomer_m1The Tg is determined by the Fox formula based only on the composition of the (meth) acrylic monomer in the monomer components used for the production of the silicone oligomer Ps. The above-mentioned Fox formula can be applied to only the (meth) acrylic monomer in the monomer components used for the production of the silicone oligomer Ps, and T can be calculated from the glass transition temperature of the homopolymer of each (meth) acrylic monomer and the weight fraction of each (meth) acrylic monomer in the total amount of the (meth) acrylic monomers_m1. Using glass transition temperature T_m1The initial adhesion is easily suppressed at a temperature higher than 0 ℃ in the case of the silicone oligomer Ps. In addition, by using the glass transition temperature T_m1The silicone oligomer Ps at a temperature higher than 0 ℃ makes it easy to obtain a pressure-sensitive adhesive sheet having a large increase ratio of adhesive strength.

In several ways, T_m1May be at least-20 ℃ or higher, may be at least-10 ℃ or higher, may be at least 0 ℃ or higher, or may be at least 10 ℃. T is_m1When the thickness becomes high, there is a tendency that the adhesive force at the initial stage of attachment can be more effectively suppressed. In addition, T_m1For example, the temperature may be 90 ℃ or lower, 80 ℃ or lower, 70 ℃ or lower, or 70 ℃ or lower. T is_m1When the thickness is low, the adhesive force tends to be easily increased by heating. The techniques disclosed herein may use T_m1Preferably, the silicone oligomer Ps is used in a range of, for example, -20 ℃ to 90 ℃, or-10 ℃ to 80 ℃, or 0 ℃ to 70 ℃.

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

In order to adjust the molecular weight of the silicone oligomer Ps, a chain transfer agent may be used. Examples of chain transfer agents to be used include: a compound having a mercapto group such as octyl mercaptan, lauryl mercaptan, tert-nonyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol, alpha-thioglycerol, etc.; thioglycolic acid esters such as thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycolic acid esters of ethylene glycol, thioglycolic acid esters of neopentyl glycol, and thioglycolic acid esters of pentaerythritol; alpha-methylstyrene dimer; and so on.

The amount of the chain transfer agent to be used is not particularly limited, and is usually 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight, and more preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the monomer. By adjusting the amount of the chain transfer agent to be added as described above, the silicone oligomer Ps having an appropriate molecular weight can be obtained. The chain transfer agent may be used singly or in combination of two or more.

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

By blending the silicone oligomer Ps described above in the pressure-sensitive adhesive layer, the silicone oligomer Ps can function well as a retardation agent for increasing the adhesive strength. The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in such a manner that the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a base polymer and a retardation agent for increasing the adhesive strength, and the retardation agent for increasing the adhesive strength contains a silicone oligomer Ps. Here, the reason why the silicone oligomer Ps functions as a retardation agent for increasing the adhesive force is considered as follows: in the pressure-sensitive adhesive sheet before and after the application to an adherend, the initial adhesive force is suppressed by the silicone oligomer Ps present on the surface of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive flows with time or heat after the application, whereby the amount of the silicone oligomer Ps present on the surface of the pressure-sensitive adhesive layer is reduced, the silicone oligomer Ps is compatible with the pressure-sensitive adhesive, and the adhesive force is increased. Therefore, as the adhesion force increase retarder in the technology disclosed herein, other materials that can exert the same function may be used instead of or in combination with the silicone oligomer Ps. As a non-limiting example of such a material, a polymer having a polyoxyalkylene structure in the molecule (hereinafter also referred to as "polymer Po") can be cited. The polymer Po may be, for example, a polymer containing a monomer unit derived from a monomer having a polyoxyalkylene skeleton. As a specific example, a homopolymer of any one of the above-mentioned monomers having a polyoxyalkylene skeleton, a copolymer of two or more kinds, a copolymer of one or two or more kinds of the monomers having a polyoxyalkylene skeleton and another monomer (for example, a (meth) acrylic monomer), or the like can be used as the polymer Po. The amount of the monomer having a polyoxyalkylene skeleton to be used is not particularly limited, and for example, the amount of the monomer S1 in the above-described silicone oligomer Ps may be applied to the amount of the monomer having a polyoxyalkylene skeleton in the polymer Po. The amount of the polymer Po in the pressure-sensitive adhesive layer is not particularly limited, and for example, the amount of the silicone oligomer Ps to the base polymer described above may be applied to the amount of the polymer Po to the base polymer. Alternatively, a part of the amount of the silicone oligomer Ps to be used (for example, about 5 to 95 wt%, or about 15 to 85 wt%, or about 30 to 70 wt% of the total amount of the silicone oligomer Ps) 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 ℃. In another embodiment of the present invention, the melting temperature of the silicone oligomer Ps may be-10 to 90 ℃ and 0 to 80 ℃.

< other ingredients >

(crosslinking agent)

For the purpose of adjustment of cohesive force and the like, a crosslinking agent may be used in the adhesive layer disclosed in the present specification. As the crosslinking agent, those generally used can be used, and examples thereof include: epoxy crosslinking agent, isocyanate crosslinking agent, organosilicon crosslinking agent,

Oxazoline crosslinking agents, aziridine crosslinking agents, silane crosslinking agents, alkyl etherified melamine crosslinking agents, metal chelate crosslinking agents, and the like. Particularly, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents can be suitably used. The crosslinking agent may be used singly or in combination of two or more.

Specifically, examples of the isocyanate-based crosslinking agent include: toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanates, and adducts thereof with polyhydric alcohols such as trimethylolpropane. Alternatively, a compound having at least 1 isocyanate group and 1 or more unsaturated bonds in 1 molecule, specifically 2-isocyanatoethyl (meth) acrylate or the like may be used as the isocyanate crosslinking agent. These isocyanate-based crosslinking agents may be used singly or in combination of two or more.

Examples of the epoxy crosslinking agent include bisphenol a, epichlorohydrin type epoxy resins, ethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine, N' -tetraglycidyl m-xylylenediamine, and 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane. These epoxy crosslinking agents may be used singly or in combination of two or more.

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

The crosslinking agent may be used in an amount of, for example, 0.01 part by weight or more, preferably 0.05 part by weight or more, based on 100 parts by weight of the base polymer. By increasing the amount of the crosslinking agent, higher cohesive force tends to be obtained. In some embodiments, the crosslinking agent may be used in an amount of 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more, based on 100 parts by weight of the base polymer. On the other hand, from the viewpoint of avoiding a decrease in viscosity due to an excessive increase in cohesive force, the amount of the crosslinking agent to be used is usually preferably 15 parts by weight or less, and may be 10 parts by weight or less, or may be 5 parts by weight or less, based on 100 parts by weight of the base polymer. In the adhesive containing the composition of the silicone oligomer Ps or other adhesion-force-increase retarder, it is advantageous not to use an excessive amount of the crosslinking agent from the viewpoint of better exerting the effect of the adhesion-force-increase retarder by utilizing the fluidity of the adhesive.

The technique disclosed in the present specification can be preferably carried out in a manner of using at least an isocyanate-based crosslinking agent as a crosslinking agent. From the viewpoint of achieving 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 crosslinking agent used is preferably 5 parts by weight or less, or 3 parts by weight or less, or 1 part by weight or less, or 0.7 parts by weight or less, or 0.5 parts by weight or less, relative to 100 parts by weight of the base polymer.

In order to allow any of the above-mentioned crosslinking reactions to proceed more efficiently, a crosslinking catalyst may also be used. As the crosslinking catalyst, for example, a tin-based catalyst (in particular, dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst to be used is not particularly limited, and may be, for example, approximately 0.0001 to 1 part by weight based on 100 parts by weight of the base polymer.

(silane coupling agent)

The adhesive layer disclosed in the present specification may further contain a silane coupling agent. By using the silane coupling agent, durability can be improved. As the silane coupling agent, a silane coupling agent having any suitable functional group can be used. Specifically, examples of the functional group include: vinyl, epoxy, amino, mercapto, (meth) acryloyloxy, acetoacetyl, isocyanate, styryl, polysulfide, and the like. Specific examples thereof include: vinyl-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane and vinyltributoxysilane; epoxy group-containing silane coupling agents such as gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane; amino-containing silane coupling agents such as γ -aminopropyltrimethoxysilane, N- β - (aminoethyl) - γ -aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ -triethoxysilyl-N- (1, 3-dimethylbutylidene) propylamine, and N-phenyl- γ -aminopropyltrimethoxysilane; mercapto silane-containing coupling agents such as γ -mercaptopropylmethyldimethoxysilane; styrene-containing silane coupling agents such as p-styryltrimethoxysilane; (meth) acrylic acid-containing silane coupling agents such as gamma-acryloyloxypropyltrimethoxysilane and gamma-methacryloyloxypropyltriethoxysilane; isocyanate-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; polysulfide-containing silane coupling agents such as bis (triethoxysilylpropyl) tetrasulfide, and the like. As the silane coupling agent, for example, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-mercaptopropylmethyldimethoxysilane can be suitably used.

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

The pressure-sensitive adhesive layer in the art disclosed herein may contain, as necessary, known additives that can be used in pressure-sensitive adhesives, such as a tackifier, a leveling agent, a plasticizer, a softening agent, a colorant (dye, pigment, etc.), a filler, an antistatic agent, an anti-aging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, and an antiseptic, within a range that does not significantly interfere with the effects of the present invention.

(formation of adhesive layer)

As a method for forming the pressure-sensitive adhesive layer, the following method can be used: for example, a method in which the pressure-sensitive adhesive composition is applied to a separator or the like subjected to a peeling treatment, and then dried to remove a polymerization solvent or the like to form a pressure-sensitive adhesive layer, followed by transfer to a polarizing film; or a method of applying the pressure-sensitive adhesive composition to a polarizing film, and drying the composition to remove a polymerization solvent and the like to form a pressure-sensitive adhesive layer on the polarizing film. In the case of applying the adhesive, one or more solvents other than the polymerization solvent may be added newly as appropriate.

As the separator subjected to the peeling treatment, a silicone release liner can be preferably used. In the step of forming the pressure-sensitive adhesive layer by applying the adhesive composition of the present invention to such a liner and drying the applied adhesive composition, a suitable method can be appropriately employed as a method for drying the pressure-sensitive adhesive according to the purpose. The method of drying the coating film by heating is preferably used. The heating and drying temperature is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and particularly preferably 70 to 170 ℃. By setting the heating temperature in the above range, an adhesive having excellent adhesive characteristics can be obtained.

The drying time may be suitably employed 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.

In addition, an adhesion promoting layer may be formed on the surface of the polarizing film, or an adhesive layer may be formed after various easy adhesion treatments such as corona treatment and plasma treatment. In addition, the surface of the pressure-sensitive adhesive layer may be subjected to an easy-adhesion treatment.

As a method for forming the adhesive layer, various methods can be used. Specific examples thereof include: roll coating, roll and lick coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, blade coating, air knife coating, curtain coating, lip coating, extrusion coating using a die coater, and the like.

The thickness of the adhesive layer is not particularly limited, but is, for example, about 1 to 100. mu.m, 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 can be protected with a sheet (separator) subjected to a peeling treatment until it is actually used.

Examples of the constituent material of the separator include: plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabrics, and suitable sheets such as nets, foamed sheets, metal foils, and laminates thereof, and the like.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and examples thereof include: polyethylene films, polypropylene films, polybutylene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer 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. The separator may be subjected to a mold release and antifouling treatment using a mold release agent such as silicone, fluorine, long-chain alkyl or fatty acid amide, silica powder, or the like, or an antistatic treatment such as a coating type, a mixing type, or a vapor deposition type, as required. In particular, the surface of the separator may be appropriately subjected to a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment, thereby further improving the releasability from the pressure-sensitive adhesive layer.

The sheet subjected to the peeling treatment used for producing the above-mentioned polarizing film with an adhesive layer can be used as it is as a separator for a polarizing film with an adhesive layer, and the process can be simplified.

Examples

The present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In each example, parts and% are on a weight basis. The following conditions of standing at room temperature, which are not particularly specified, are all 23 ℃ and 65% RH.

The weight average molecular weight Mw of each polymer was determined by measuring the molecular weight Mw using a GPC apparatus (HLC-8220 GPC, manufactured by Tosoh corporation) under the following conditions and converting the molecular weight into polystyrene.

Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)

Sample injection amount: 10 μ l

Eluent: THF (tetrahydrofuran)

Flow rate: 0.6ml/min

Measurement temperature: 40 deg.C

< production of one-sided protective polarizing film B >

(production of polarizer B)

One surface of a substrate of an amorphous isophthalic acid-copolymerized polyethylene terephthalate (IPA-copolymerized PET) film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of 75 ℃ was subjected to corona treatment, and an aqueous solution containing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl-modified degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon synthetic chemical industries, Ltd., trade name: Gohsefimer Z200) at a ratio of 9:1 was applied to the corona-treated surface at 25 ℃ and dried to form a PVA-based resin layer having a thickness of 11 μm, thereby producing a laminate. The resultant laminate was subjected to free-end uniaxial stretching (auxiliary stretching treatment in a gas atmosphere) of 2.0 times in the longitudinal direction (longitudinal direction) in an oven at 120 ℃ between rolls having different peripheral speeds. Next, the laminate was immersed in an insolubilization bath (an aqueous boric acid solution prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30 ℃ for 30 seconds (insolubilization treatment). Next, the polarizing plate was immersed in a dyeing solution at a liquid temperature of 30 ℃ while adjusting the iodine concentration and the immersion time so as to achieve a predetermined transmittance. In this example, an aqueous iodine solution prepared by adding 0.2 parts by weight of iodine and 1.0 part by weight of potassium iodide to 100 parts by weight of water was immersed for 60 seconds (dyeing treatment). Subsequently, the substrate was immersed in a crosslinking bath (aqueous boric acid solution prepared by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30 ℃ for 30 seconds (crosslinking treatment). Then, the laminate was immersed in an aqueous boric acid solution (aqueous solution prepared by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ℃ and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds so that the total stretching ratio became 5.5 times (stretching treatment in the aqueous solution). Then, the laminate was immersed in a cleaning bath (aqueous solution containing 4 parts by weight of potassium iodide per 100 parts by weight of water) at a liquid temperature of 30 ℃ (cleaning treatment). By the above operation, 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.

The obtained polarizer B was measured for a boric acid peak (665 cm) by attenuated total reflection spectroscopy (ATR) measurement using polarized light as measurement light, using a fourier transform infrared spectrophotometer (FTIR) (product name "spectra 2000", manufactured by Perkin Elmer corporation)^-1) Intensity of (2) and control Peak (2941 cm)^-1) The strength of (2). The boric acid amount index was calculated from the obtained boric acid peak intensity and the control peak intensity by the following formula, and the boric acid content (% by weight) was determined from the boric acid amount index by the following formula.

(boric acid amount index) ═ (boric acid peak 665 cm)^-1Intensity of (2)/(control Peak 2941 cm)^-1Strength of (2)

(boric acid content (% by weight)) - (boric acid amount index) × 5.54+4.1

(preparation of transparent protective film B)

Transparent protective film B: the easy-adhesion-treated surface of a (meth) acrylic resin film having a lactone ring structure and having a thickness of 40 μm was subjected to corona treatment and used.

(preparation of adhesive for transparent protective film B)

An ultraviolet-curable adhesive was prepared by mixing 40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acryloyl morpholine (ACMO), and 3 parts by weight of a photoinitiator IRGACURE 819 (BASF corporation).

(preparation of Single-sided protective polarizing film B)

The ultraviolet-curable adhesive was applied to the surface of the polarizer of the optical film laminate so that the thickness of the cured adhesive layer became 0.5 μm, and the transparent protective film B was bonded to the polarizer.

(active energy ray)

The ultraviolet irradiation was performed using a gallium-sealed metal halide lamp and an irradiation apparatus: light HAMMER10 manufactured by Fusion UV Systems, Inc, valve: v valve, peak illuminance: 1600mW/cm²Cumulative dose of radiation 1000/mJ/cm²(wavelength 380 to 440nm) and the illuminance of ultraviolet light were measured by using Sola-Check system manufactured by Solatell corporation.

Next, the amorphous PET substrate was peeled off, and a one-side protective polarizing film B using a thin polarizer was produced. Using the obtained one-side protective polarizing film B, the monomer transmittance T and the degree of polarization P of the polarizer B were measured by the following methods, and as a result, the monomer transmittance T of the polarizer B was 42.8% and the degree of polarization P of the polarizer B was 99.99%.

The single transmittance T and the degree of polarization P of the polarizer B of the obtained single-sided protective polarizing film B were measured using a spectral transmittance measuring instrument with an integrating sphere (Dot-3 c from mura color technical research institute). The degree of polarization P is determined by applying the transmittance (parallel transmittance: Tp) when 2 identical single-side protective polarizing films B are stacked such that their transmission axes are parallel to each other and the transmittance (orthogonal transmittance: Tc) when they are stacked such that their transmission axes are orthogonal to each other to the following equation.

Polarization degree P (%) { (Tp-Tc)/(Tp + Tc) }^1/2×100

Each transmittance is a transmittance represented by a Y value obtained by measuring a 2-degree field of view (C light source) according to JIS Z8701 and correcting visibility when the fully polarized light obtained by the glan-taylor prism polarizer is assumed to be 100%.

< production of polarizing film A with both sides protected >

(production of polarizer A)

A polyvinyl alcohol film having a thickness of 75 μm and an average polymerization degree of 2400 and a saponification degree of 99.9 mol% was immersed in warm water at 30 ℃ for 60 seconds to swell the film. Then, the film was immersed in an aqueous solution of iodine/potassium iodide (0.5/8 by weight) having a concentration of 0.3%, and the film was dyed while being stretched to 3.5 times. Then, stretching was performed in an aqueous solution of boric acid ester at 65 ℃ so that the total stretching ratio became 6 times. After the stretching, the obtained film was dried in an oven at 40 ℃ for 3 minutes to obtain PVA based polarizer A (SP value: 32.8, thickness: 23 μm). The water content was 14% by weight.

(preparation of transparent protective film A)

To the thickness of 40 μm and the moisture permeability of 60g/m²The easy-adhesion treated surface of the acrylic resin film (SP value 22.2) was subjected to corona treatment for 24 hours and then used.

(active energy ray)

As the active energy ray, the following devices were used:

ultraviolet irradiation device (metal halide lamp with gallium sealed): light HAMMER10 manufactured by fusion UV Systems, Inc

Valve: v-valve

Peak illuminance: 1600mW/cm²

Cumulative dose 1000/mJ/cm²(wavelength 380-440 nm). In addition, the ultraviolet rayThe illuminance was measured by using Sola-Check system manufactured by Solatell.

(preparation of active energy ray-curable adhesive (1))

N-hydroxyethyl acrylamide (SP value: 29.6, homopolymer Tg: 123 ℃ C., manufactured by Kyowa Kasei Co., Ltd.) 38.3 parts as a radical polymerizable compound (A), tripropylene glycol diacrylate (trade name: ARONIX M-220, SP value: 19.0, homopolymer Tg: 69 ℃ C., manufactured by Toyo Seisaku K.K.) 19.1 parts as a radical polymerizable compound (B), acryloylmorpholine (SP value: 22.9, homopolymer Tg: 150 ℃ C., manufactured by Kyowa Kasei Co., Ltd.) 38.3 parts as a radical polymerizable compound (C), and a photopolymerization initiator (trade name: YAKACUDET X-S, diethylthioxanthone, manufactured by Kyowa Kasei Co., Ltd.) 1.4 parts were mixed and stirred at 50 ℃ for 1 hour to obtain an active energy ray-curable adhesive (1).

(preparation of polarizing film A)

After a urethane-based pressure-sensitive adhesive layer having a thickness of 0.5 μm was formed on the acrylic resin film, the pressure-sensitive adhesive layer was coated with the active energy ray-curable adhesive (1) so that the thickness of the pressure-sensitive adhesive layer became 0.5 μm using an MCD coater (manufactured by Fuji mechanical Co., Ltd.) (cell shape: number of lines of honeycomb and gravure roll: 1000 lines/inch, rotation speed 140%/line speed). Next, the acrylic resin film was bonded to both surfaces of the polarizer a as transparent protective films on the visible side and the panel side by the adhesive (1) using a roll machine. Then, the acrylic resin film after bonding was heated from both sides to 50 ℃ by an IR heater, and both sides were irradiated with the above ultraviolet rays to cure the active energy ray-curable adhesive (1). Further, hot air drying was performed at 70 ℃ for 3 minutes to obtain a polarizing film a having transparent protective films a on both surfaces of the polarizer a (table 1). The lamination was carried out at a linear speed of 25 m/min.

[ Table 1]

< preparation of adhesive >

(preparation of Polymer solution D)

A four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a condenser was charged with a monomer mixture containing 89.82 parts of N-butyl acrylate, 8 parts of methyl methacrylate, 1.5 parts of N-vinylpyrrolidone, 0.2 part of acrylic acid, and 0.48 part of 4-hydroxybutyl acrylate. Further, 0.15 part of 2, 2' -azobisisobutyronitrile as a polymerization initiator was added together with ethyl acetate to 100 parts of the monomer mixture (solid content), nitrogen gas was introduced while slowly stirring to replace nitrogen gas, and then the liquid temperature in the flask was maintained at about 60 ℃ to carry out polymerization 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 130 ten thousand with the solid content concentration adjusted to 20%.

An isocyanate-based crosslinking agent (product name "Takenate D160N" manufactured by Mitsui chemical Co., Ltd.) was added in an amount of 0.25 part, a peroxide-based crosslinking agent (product name "NYPER BMT" manufactured by Nippon fat and oil Co., Ltd.) was added in that order, and an acetoacetylsilane-containing coupling agent (product name "A-100" manufactured by Sokko chemical Co., Ltd.) was added in that order, based on 100 parts of the solid content of the acrylic polymer solution D, to prepare a pressure-sensitive adhesive polymer solution D.

(preparation of Polymer solution A)

100 parts of butyl acrylate, 5 parts of acrylic acid, 0.075 part of 2-hydroxyethyl acrylate, and 0.3 part of 2, 2' -azobisisobutyronitrile were added to a reaction vessel equipped with a condenser, a nitrogen gas inlet tube, a thermometer, and a stirring device together with ethyl acetate to prepare a solution. Subsequently, the resulting solution was stirred while blowing nitrogen gas, and reacted at 60 ℃ for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight Mw of 220 ten thousand. Ethyl acetate was further added to the acrylic polymer-containing solution to obtain an acrylic polymer solution a having a solid content concentration of 30%.

An adhesive polymer solution a was prepared by mixing 0.6 parts of a crosslinking agent containing a compound having an isocyanate group as a main component (product name "Coronate L" manufactured by japan polyurethane corporation) and 0.075 parts of γ -glycidoxypropyltrimethoxysilane (product name "KBM-403" manufactured by shin-Etsu chemical industries) as a silane coupling agent in this order with respect to 100 parts of the solid content of the acrylic polymer solution a.

(preparation of Polymer solution B)

94 parts of 2-ethylhexyl acrylate (2EHA), 6 parts of acrylic acid and 0.3 part of 2, 2' -azobisisobutyronitrile were added to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer together with ethyl acetate to prepare a solution. Subsequently, the resulting solution was stirred while blowing nitrogen gas, and reacted at 60 ℃ for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight Mw of 220 ten thousand. Ethyl acetate was further added to the solution containing the acrylic polymer to obtain an acrylic polymer solution (B) having a solid content concentration of 30%.

An adhesive polymer solution B was prepared by sequentially mixing 0.6 parts of a crosslinking agent containing a compound having an isocyanate group as a main component (trade name "Coronate L", manufactured by japan polyurethane corporation) and 0.075 parts of γ -glycidoxypropyltrimethoxysilane (trade name "KBM-403", manufactured by shin-Etsu chemical industries, Ltd.) as a silane coupling agent with respect to 100 parts of the solid content of the acrylic polymer solution (B).

(preparation of Polymer solution C)

99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate, and 0.3 part of 2, 2-azobisisobutyronitrile per 100 parts of the monomer (solid content) were added together with ethyl acetate to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer, and reacted at 60 ℃ for 4 hours under a nitrogen gas flow, and then ethyl acetate was added to the reaction solution to obtain a polymer solution C (solid content concentration 30 wt%) containing an acrylic polymer having a weight average molecular weight of 165 ten thousand.

A binder polymer solution C was prepared by mixing 0.3 part of dibenzoyl peroxide (NYPER BMT, manufactured by Nippon fat and oil Co., Ltd.), 0.1 part of trimethylolpropane xylylene diisocyanate (Takenate D110N, manufactured by Mitsui Kogya chemical Co., Ltd.) and 0.2 part of a silane coupling agent (A-100, manufactured by Sukikai chemical Co., Ltd., containing an acetoacetylsilane coupling agent) with 100 parts of the solid content of the acrylic polymer solution C.

The compositions of the acrylic polymer solution (a) (polymer a), the acrylic polymer solution (B) (polymer B), the acrylic polymer solution (C) (polymer C), and the acrylic polymer solution (D) (polymer D) are shown in table 2 below.

[ Table 2]

(preparation of Silicone oligomer A)

100 parts of ethyl acetate, 40 parts of MMA, 20 parts of n-Butyl Methacrylate (BMA), 20 parts of 2-ethylhexyl methacrylate (2EHMA), 8.7 parts of a polyorganosiloxane skeleton-containing methacrylate monomer (trade name: X-22-174ASX, manufactured by shin-Etsu chemical Co., Ltd.) having a functional group equivalent of 900g/mol, 11.3 parts of a polyorganosiloxane skeleton-containing methacrylate monomer (trade name: KF-2012, manufactured by shin-Etsu chemical Co., Ltd.) having a functional group equivalent of 4600g/mol, and 0.2 parts of methyl thioglycolate as a chain transfer agent were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, a condenser, and a dropping funnel. Then, after stirring at 70 ℃ for 1 hour in a nitrogen atmosphere, 0.2 part of 2,2 '-azobisisobutyronitrile as a thermal polymerization initiator was added, and after reacting at 70 ℃ for 2 hours, 0.1 part of 2, 2' -azobisisobutyronitrile as a thermal polymerization initiator was added, followed by reacting at 80 ℃ for 3 hours. Thus, a solution of silicone oligomer a was obtained. The silicone oligomer a had a weight average molecular weight Mw of 18000.

(preparation of other Silicone oligomers B. about. D, E1, E, G)

Silicone oligomers B to D, E1 and E, G were prepared in the same manner as silicone oligomer a except that the monomer composition and parts by mass were changed to the constituent components shown in table 3.

[ Table 3]

(preparation of adhesive solution)

To the adhesive polymer solution a prepared above, 1 part of the silicone oligomer a was blended to prepare an acrylic adhesive solution used in example 1. Similarly, the adhesive polymer solutions and silicone oligomers described in table 4 below were used to prepare acrylic adhesive solutions used in examples 2 to 20.

< production of one-sided protective polarizing film with adhesive layer >

[ example 1] to [ example 20]

The prepared acrylic pressure-sensitive adhesive A was uniformly applied to the surface of a polyethylene terephthalate film (separator) treated with a silicone-based release agent, and dried in an air-circulating oven at 155 ℃ for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 20 μm on the surface of each separator. The adhesive layer thus produced was laminated to the polarizer side of the single-sided protective polarizing film B thus produced, to produce a single-sided protective polarizing film with an adhesive layer.

Comparative example 1

A polarizing film with an adhesive layer was produced in the same manner as in example 1, except that the silicone oligomer a was used in comparative example 1.

Comparative examples 2 to 5

Polarizing films with pressure-sensitive adhesive layers were produced in the same manner as in example 1, except that an ether group-containing polysiloxane (trade name "modified silicone oil KF-353", manufactured by shin-Etsu chemical Co., Ltd.) or an organosilicon oligomer G was used in place of the organosilicon oligomer a in comparative examples 2 to 5, and the blending amount was changed as shown in table 4.

Comparative example 6

A polarizing film with an adhesive layer was produced in the same manner as in example 1, except that the single-side protective polarizing film B was changed to the double-side protective polarizing film a in comparative example 6.

The polarizing films with adhesive layers obtained in examples 1 to 20 and comparative examples 1 to 6 were evaluated as follows, and the results are shown in table 4.

< evaluation of durability >

The separator of the polarizing film (15 inches) having the adhesive layer was peeled off, and the resultant was attached to alkali-free glass (EG-XG, manufactured by Corning Co.) having a thickness of 0.7mm by using a laminator. Then, the polarizing film was completely adhered to the alkali-free glass by autoclave treatment at 50 ℃ and 0.5MPa for 15 minutes. Then, the sheets were put into a heating oven (heating) at 80 ℃ and the presence or absence of peeling of the polarizing plate after 500 hours was evaluated according to the following criteria.

A: peeling was not confirmed at all.

B: foaming was confirmed to an extent that could not be confirmed by visual observation.

C: peeling was observed to such an extent that it could not be observed by visual observation.

D: small foaming or peeling was observed visually and could be confirmed.

E: significant foaming or peeling was confirmed.

< evaluation of adhesive force >

The polarizing film with the adhesive layer thus produced was cut into a length of 120mm × a width of 25mm to obtain a sample. The sample was pressure-bonded to an alkali-free glass plate (EG-XG, manufactured by Corning corporation) having a thickness of 0.7mm by reciprocating a 2kg roller 1 time, and the sample was aged at 23 ℃ for 1 hour, and then the adhesive force of the sample was measured. Then, the sample was pressed with a 2kg roller 1 time in a reciprocating manner, and after completely adhering the sample by autoclave treatment for 15 minutes at 50 ℃ and 5atm, the sample was heated in a heating oven at 60 ℃ for 2 hours and 24 hours, and then the adhesive force of the sample was measured. The adhesive strength was determined by measuring the adhesive strength (N/25mm, measurement length 80mm) when the above sample was peeled at a peel angle of 90 ℃ and a peel speed of 300mm/min using a tensile tester (autograph SHIMAZU AG-11 OKN). The measurement was performed 200 times at 1 time/0.5 second intervals, and the average value was used as the measurement value. The number of samples tested was performed with 3 samples tested. The reworkability was determined from the adhesion evaluation based on the following criteria.

A: 3.5N/25mm or less, and 90% of the re-operation success.

B: more than 3.5N/25mm and not more than 4N/25mm, and the re-operation success rate is 80% or more.

C: more than 4N/25mm and not more than 5N/25mm, and the re-operation success rate is more than 70%.

D: more than 5N/25mm and not more than 6N/25mm, and the operation success rate is more than 60%.

E: over 6N/25mm and failure of the re-operation by more than 40%.

< method for measuring anchoring force of adhesive layer >

A25 mm wide polarizing film with an adhesive layer was pressure-bonded to a treated surface of a polyethylene terephthalate film (trade name "125 Tetlight OES" (thickness 125 μm) manufactured by Kakukoku industries Co., Ltd.) obtained by vapor deposition of indium tin oxide by reciprocating 1 time using a 2kg roller, and after 1 minute of aging at 23 ℃, the adhesion strength of the polyethylene terephthalate film to each adhesive layer was measured at 300mm/min in the 180-degree direction. The anchoring force was determined according to the following criteria.

A: 15N/25mm or more

B: 10N/25mm or more and less than 15N/25mm

C: 7.5N/25mm or more and less than 10N/25mm

D: less than 7.5N/25mm

E: adhesive force after press-bonding with a roller of less than 2kg

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

Claims

1. A polarizing film with an adhesive layer, comprising:

wherein the adhesive layer comprises a base polymer and a silicone oligomer Ps, and 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 Tg of the organic silicon oligomer Ps is more than-50 ℃ and less than 100 ℃, the equivalent weight of organic silicon functional groups of side chains is 1000-20000 g/mol, and the weight average molecular weight is more than 10000 and less than 300000.

2. The adhesive layer-equipped polarizing film according to claim 1,

the silicone oligomer Ps contains, as monomer units, a monomer S1 having a polyorganosiloxane skeleton, and a monomer having a homopolymer glass transition temperature of-70 ℃ or higher and 180 ℃ or lower.

3. The adhesive layer-equipped polarizing film according to claim 1 or 2,

the base polymer contains, as monomer units, at least 80% by weight of an alkyl (meth) acrylate (A) having a homopolymer glass transition temperature of-80 ℃ to 0 ℃.

4. The adhesive layer-equipped polarizing film according to claim 3,

the base polymer further contains 5% by weight or less of at least one polar monomer (B) selected from a carboxyl group-containing monomer (B1) and a nitrogen-containing monomer (B2) as a monomer unit.

5. The adhesive layer-equipped polarizing film according to claim 4,

the base polymer further contains 0.1 to 18 wt% of alkyl methacrylate with a glass transition temperature of a homopolymer of 0 ℃ to 180 ℃, and 0 to 5 wt% of hydroxyl group-containing monomer as a monomer unit.

6. The adhesive layer-equipped polarizing film according to any one of claims 1 to 5,

the weight average molecular weight of the base polymer is 50-250 ten thousand.

7. The adhesive layer-equipped polarizing film according to any one of claims 1 to 6,

the thickness of the polarizer is more than 0 μm and less than 12 μm.

8. The adhesive layer-equipped polarizing film according to any one of claims 1 to 7,

the melting temperature of the organic silicon oligomer Ps is-20-120 ℃.