JP7339457B2 - Polarizing film with adhesive layer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polarizing film with an adhesive layer.

In a liquid crystal display device, it is essential to arrange polarizing films on both sides of a glass substrate forming a liquid crystal panel surface because of its image forming method. A polarizing film is generally a polarizer made of a polyvinyl alcohol film and a dichroic material such as iodine, and a protective film is attached to one or both sides of the polarizer with a polyvinyl alcohol adhesive or the like. .

When the polarizing film is adhered to a liquid crystal cell or the like, an adhesive is usually used. Also,
The adhesive is provided in advance as an adhesive layer on one side of the polarizing film because it has the advantages of being able to instantly fix the polarizing film and not requiring a drying process to fix the polarizing film. That is, a polarizing film with an adhesive layer is generally used for attaching a polarizing film (Patent Documents 1 and 2).

In addition, when a polarizing film or a polarizing film with an adhesive layer is attached to a glass substrate of a liquid crystal panel, durability is required. It is required that problems such as peeling and lifting due to the agent layer do not occur.

In this way, adhesives used in polarizing films are required to be highly durable, but on the other hand, there is also a growing demand for reworkability in order to recover from defects and pasting mistakes that occur during defective processes when laminating polarizing plates. . Reworkability is an important item because demand for revitalization of panels is increasing due to the trend of thinner and larger panels in recent years. However, high durability and reworkability are in a trade-off relationship, and it is very difficult to achieve both.

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

In view of the above-described background art, there is a strong demand for a polarizing film with an adhesive layer that can have both high durability and reworkability, which are in a trade-off relationship.

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 and an adhesive layer,
The pressure-sensitive adhesive layer contains a base polymer and a silicone oligomer Ps,
The base polymer is a (meth)acrylic polymer,
The silicone oligomer Ps is contained in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer,
The silicone oligomer Ps has a Tg of −50° C. or higher and 100° C. or lower, a side chain silicone functional group equivalent weight of 1000 to 20000 g/mol, and a weight average molecular weight Mw of 1.
0000 or more and 300000 or less,
Polarizing film with adhesive layer.

(2) The adhesive according to (1) above, wherein 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° C. or more and 180° C. or less. Polarizing film with an agent layer.

(3) As a monomer unit of the base polymer, the glass transition temperature of the homopolymer is -
The polarizing film with an adhesive layer according to (1) or (2) above, containing 80% by weight or more of the alkyl (meth)acrylate (A) having a temperature of 60°C or higher and 0°C or lower.

(4) As a monomer unit of the base polymer, a carboxyl group-containing monomer (b1
) and a nitrogen-containing monomer (b2), the polarizing film with an adhesive layer according to (3) above, further containing 0 to 20% by weight of at least one polar monomer (B) selected from the group consisting of (b2).

(5) The above (1), wherein the weight average molecular weight Mw of the base polymer is 500,000 to 2,500,000.
The polarizing film with an adhesive layer according to any one of (4).

(6) The above (1) to , wherein the silicone oligomer Ps has a melting temperature of 0 to 100°C.
The polarizing film with an adhesive layer according to any one of (5).

ADVANTAGE OF THE INVENTION According to this invention, the polarizing film with an adhesive layer which can provide durability by increasing adhesive force after a heating can be provided, imparting reworkability immediately after bonding.

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

Preferred embodiments of the present invention are described below. Matters other than those specifically referred to in this specification that are necessary for the implementation of the present invention are applicable based on the teaching of the implementation of the invention described in this specification and the common general knowledge as of the filing. understandable to traders. The present invention can be implemented based on the contents disclosed in this specification and common general technical knowledge in the field.

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

FIG. 1 schematically shows the structure of a polarizing film with an adhesive layer according to one embodiment. This polarizing film 10 with an adhesive layer is configured as a polarizing film with an adhesive layer including a polarizing film 3 and an adhesive layer 4 provided on one side thereof. In FIG. 1, the polarizing film 3 is composed of a polarizer 1 and protective films 2 and 2' provided on both sides of the polarizer 1, but the protective film may be provided only on one side of the polarizer. . The adhesive layer 4 is the polarizing film 3
, ie without the intention of separating the adhesive layer 4 from the polarizing film 3 . The pressure-sensitive adhesive layer-attached polarizing film 10 is used by attaching the pressure-sensitive adhesive layer 4 to an adherend. As the separator 5, for example, a sheet-like base material (liner base material) having a release layer provided on one side thereof with a release treatment agent so that the one side becomes a release surface can be preferably used. The structure of the pressure-sensitive adhesive layer-attached polarizing film is not limited to the embodiment schematically shown in FIG.

<Polarizer>
The polarizer is not particularly limited, and various polarizers can be used. As a polarizer, for example, hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films are coated with dichroic iodine or dichroic dyes. Polyene-based oriented films such as those obtained by adsorbing a substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like can be mentioned. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable. Although the thickness of these polarizers is not particularly limited, it is generally 2 to 25 μm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing a polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. can. It can also be immersed in an aqueous solution of potassium iodide, which may contain boric acid, zinc sulfate, zinc chloride, etc., if necessary. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing.
By washing the polyvinyl alcohol film with water, dirt and anti-blocking agents on the surface of the polyvinyl alcohol film can be washed away, and by swelling the polyvinyl alcohol film, uneven dyeing and other unevenness can be prevented. be. Stretching may be performed after dyeing with iodine, stretching may be performed while dyeing, or dyeing with iodine may be performed after stretching. It can also be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

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

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer used in the present invention is not particularly limited. Adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, and the like can be used. Various base polymers can be used depending on the adhesive used.

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

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

(1) Alkyl (meth)acrylate (A)
A (meth)acrylic polymer usually contains 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, linear or branched C1 to C20 (meth)acrylic acid alkyl esters can be used. Examples of C1 to C20 (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, ( meth) hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (
meth) isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, (meth) ) tridecyl acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, iso-octadecyl (meth) acrylate, (meth) ) nonadecyl acrylate, eicosyl (meth)acrylate and the like, but are not limited thereto. These (meth)acrylic acid alkyl esters can be used alone or in combination.

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

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

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

In a preferred embodiment of the present invention, an alkyl (meth)acrylate (A) having a homopolymer glass transition temperature of −60° C. or higher and 0° C. or lower is
) can be contained in an amount of 80% by weight or more.

In one embodiment of the present invention, the (meth)acrylic polymer, in addition to the alkyl (meth)acrylate (A) as a main component, optionally other monomers copolymerizable with the alkyl (meth)acrylate (Copolymerizable monomer) may be further included. As a copolymerizable monomer, a monomer having a polar group (for example, a carboxy group, a hydroxyl group, a nitrogen atom-containing ring, etc.) can be preferably used. A monomer having a polar group can be useful for introducing a cross-linking point into the acrylic polymer or increasing the cohesive strength of the (meth)acrylic polymer. Copolymerizable monomers can be used singly or in combination of two or more.

Specific non-limiting examples of copolymerizable monomers include carboxy group-containing monomers, acid anhydride group-containing monomers, hydroxyl group-containing monomers, sulfonic acid group- or phosphoric acid group-containing monomers, epoxy group-containing monomers, and cyano group-containing monomers. 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)acrylic acid esters having an alicyclic hydrocarbon group, (meth)acrylic acid esters having an aromatic hydrocarbon group, and others, (meth)acrylic Heterocyclic ring-containing (meth)acrylates such as tetrahydrofurfuryl acid, halogen atom-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicone (meth)
Silicon atom-containing (meth)acrylates such as acrylates, (meth)acrylic acid esters obtained from terpene compound derivative alcohols, and the like can be mentioned.

Carboxy group-containing monomers include, for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid;
Examples of acid anhydride group-containing monomers include maleic anhydride and itaconic anhydride;
Examples of hydroxyl group-containing monomers include 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, hydroxyalkyl (meth)acrylates such as 12-hydroxylauryl (meth)acrylate and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate;
Monomers containing a sulfonic acid group or a phosphoric acid group include, for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2
-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like;
Examples of epoxy group-containing monomers include glycidyl (meth)acrylate and (meth)
epoxy group-containing acrylates such as acrylate-2-ethyl glycidyl ether, allyl glycidyl ether, (meth)acrylate glycidyl ether, and the like;
Examples of cyano group-containing monomers include acrylonitrile, methacrylonitrile, and the like;
Examples of isocyanate group-containing monomers include 2-isocyanatoethyl (meth)
acrylates and the like;
Examples of amide group-containing monomers include (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl ( meth)acrylamide, N,N-
Di(n-butyl)(meth)acrylamide, N,N-dialkyl(meth)acrylamide such as N,N-di(t-butyl)(meth)acrylamide; N-ethyl(meth)acrylamide, N-isopropyl(meth) ) acrylamide, N-butyl (meth)acrylamide,
N-alkyl (meth)acrylamides such as Nn-butyl (meth)acrylamide; N-
N-vinylcarboxylic acid amides such as vinylacetamide; Others, N,N-dimethylaminopropyl(meth)acrylamide, hydroxyethylacrylamide, N-methylol(meth)acrylamide, N-ethylol(meth)acrylamide, N-methylolpropane (Meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-(
meth)acryloylmorpholine and the like;
Examples of monomers having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N
-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl -2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N
- vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N
-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine and the like (for example, lactams such as N-vinyl-2-caprolactam);
Examples of monomers having a succinimide skeleton include N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyhexamethylenesuccinimide and the like. be
Examples of maleimides include N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like;
Examples of itaconimides include N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N - such as lauryl itaconimide;
Examples of aminoalkyl (meth)acrylates include, for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-(meth)acrylate,
diethylaminoethyl, t-butylaminoethyl (meth)acrylate;
Examples of alkoxyalkyl (meth)acrylates include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and (meth)acrylic acid. ethoxypropyl and the like;
Examples of vinyl esters include vinyl acetate, vinyl propionate, and the like;
Vinyl ethers include, for example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether;
Examples of aromatic vinyl compounds include styrene, α-methylstyrene, vinyltoluene, and the like;
Olefins include, for example, ethylene, butadiene, isoprene, isobutylene, and the like;
Examples of (meth)acrylic acid esters having an alicyclic hydrocarbon group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like;
(Meth)acrylic acid esters having an aromatic hydrocarbon group include, for example, phenyl (
meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate and the like.

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

In one embodiment of the present invention, the (meth)acrylic polymer contains, in addition to alkyl (meth)acrylate as a main component, a hydroxyl group-containing monomer as described above (typically , a (meth)acrylic monomer containing a hydroxyl group). Examples of hydroxyl group-containing monomers include, as described above, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,
Hydroxybutyl, 3-hydroxypropyl (meth)acrylate, 4 (meth)acrylate
-hydroxybutyl, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclo hydroxyalkyl (meth)acrylates such as hexyl)methyl (meth)acrylate;
2-hydroxyethyl acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylate
6-Hydroxyhexyl acrylate and the like can be preferably used. Among them, preferred examples include 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA). By using a hydroxyl group-containing monomer, it is possible to adjust the cohesive strength and polarity of the pressure-sensitive adhesive and improve the pressure-sensitive adhesive strength after heating. In addition, the hydroxyl group-containing monomer increases the hydrophilicity of the pressure-sensitive adhesive layer, and can be useful for suppressing deterioration of transparency due to moisture. When including a hydroxyl group-containing monomer, the amount of the hydroxyl group-containing monomer used is not particularly limited,
Generally, it can be, for example, 0.01% by weight or more, 0.1% by weight or more, or 0.5% by weight or more based on the total amount of monomer units for preparing the (meth)acrylic polymer.

Further, in one embodiment of the present invention, the (meth)acrylic polymer, in addition to the alkyl (meth)acrylate as the main component, may optionally be a polyfunctional polymer for the purpose of adjusting the cohesive strength of the pressure-sensitive adhesive layer. may contain a polar monomer. Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate,
1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl ( meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl diol (meth) acrylate, hexyl diol di (meth)
acrylates and the like. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types. The amount of the polyfunctional monomer used varies depending on its molecular weight, number of functional groups, etc., but it is usually alkyl (meth)acrylate (A
) is suitably in the range of 0.01% to 3.0% by weight, and may be 0.02% to 2.0% by weight. 03% to 1% by weight
. It may be 0% by weight.

(2) Polar monomer (B)
In one embodiment of the present invention, the base polymer contains at least one polar monomer (B) selected from the group consisting of carboxyl group-containing monomers (b1) and nitrogen-containing monomers (b2) as copolymerizable monomer units. can further include:

In one embodiment of the present invention, the polar monomer (B) may be contained in an amount of 0-20% by weight based on the weight of the base polymer. The polar monomer (B) is preferably 0.1-17.5 wt%, more preferably 1-15 wt%, based on the weight of the base polymer.

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

(2-2) Nitrogen-containing monomer (b2)
In the present invention, the base polymer can contain nitrogen-containing monomers (b2) as copolymerizable monomer units. Nitrogen-containing monomers (b2) include, for example, vinyl-based monomers having a lactam ring (for example, vinylpyrrolidone-based monomers such as N-vinylpyrrolidone and methylvinylpyrrolidone, and β-lactam rings, δ-lactam rings, and ε- vinyllactam-based monomers having a lactam ring such as a lactam ring); maleimide-based monomers such as maleimide, N-cyclohexylmaleimide, and N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N , N-diethyl (meth)acrylamide, N-hexyl (meth)acrylamide, N-methyl (meth)acrylamide, N-butyl (meth)acrylamide, N-butyl (meth)acrylamide, N-
(N-substituted) amide-based monomers such as methylol (meth)acrylamide and N-methylolpropane (meth)acrylamide; (meth)aminoethyl acrylate, aminopropyl (meth)acrylate, (meth)acrylic acid N,N- dimethylaminoethyl, t-butylaminoethyl (meth)acrylate, 3-(3-pyrinidyl)propyl (meth)acrylate and other aminoalkyl (meth)acrylate monomers; N-(meth)acryloyloxymethylene succinimide, N - (meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide and other succinimide monomers; acrylonitrile, methacrylonitrile and other cyano (meth)acrylate monomers; vinylpyridine, Examples include, but are not limited to, vinyl piperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, and the like. In a preferred embodiment of the invention, the nitrogen-containing monomer (b2) is N
-vinylpyrrolidone, methylvinylpyrrolidone, N,N-dimethyl(meth)acrylamide. In a more preferred embodiment of the invention the nitrogen-containing monomer (b2) may be N-vinylpyrrolidone.

The method for obtaining the (meth)acrylic polymer is not particularly limited, and various known methods for synthesizing acrylic polymers such as solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method, photopolymerization method, etc. can be appropriately adopted polymerization method. In some embodiments,
A solution polymerization method can be preferably employed. The polymerization temperature at the time of solution polymerization can be appropriately selected according to the types of monomers and solvents used, the type of polymerization initiator, and the like.
It can be about 170° C. (typically about 40° C. to 140° C.).

The initiator used for polymerization can be appropriately selected from conventionally known thermal polymerization initiators, photopolymerization initiators, and the like, depending on the polymerization method. A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

Examples of thermal polymerization initiators include azo polymerization initiators (e.g., 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis ( 2-methylpropionate) dimethyl, 4,4′-azobis-4-cyanovaleric acid,
azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2, 2′-azobis(2-methylpropionamidine) disulfate, 2,2′-azobis(N,N′-dimethyleneisobutylamidine) dihydrochloride, etc.); persulfates such as potassium persulfate; peroxides polymerization initiators (eg, dibenzoyl peroxide, t-butyl permaleate, lauroyl peroxide, etc.); redox polymerization initiators; The amount of the thermal polymerization initiator used is not particularly limited, but for example, 0.01 to 5 parts by weight, preferably 0.05 to 5 parts by weight, per 100 parts by weight of the monomer component used for preparing the acrylic polymer. The amount can be in the range of 3 parts by weight.

The photopolymerization initiator is not particularly limited. oxime photoinitiator, benzoin photoinitiator,
Benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and the like can be used. The amount of the photopolymerization initiator used is not particularly limited, but for example, 0.01 to 5 parts by weight with respect to 100 parts by weight of the monomer component used for preparing the acrylic polymer.
Preferably, the amount can be in the range of 0.05 parts by weight to 3 parts by weight.

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

In the present invention, the weight average molecular weight Mw of the base polymer may be 500,000 to 2,500,000. In one embodiment of the present invention, the weight average molecular weight Mw of the base polymer is preferably 700,000 to 2,700,000, more preferably 800,000 to 2,500,000.

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

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

The silicone oligomer Ps used in the present invention has a weight average molecular weight Mw of 1
It is in the range of 0,000 to 300,000. In one embodiment of the present invention, the weight average molecular weight Mw of the silicone oligomer Ps is preferably 12500 or more and 250000
It may be 0 or less, more preferably 15,000 or more and 2,000,000 or less. When the weight-average molecular weight Mw of the silicone oligomer Ps is within the above range, the compatibility and mobility in the pressure-sensitive adhesive layer can be easily adjusted to an appropriate range, and the initial low tackiness and strong tackiness during use can be improved. It becomes easier to realize a pressure-sensitive adhesive sheet that is compatible at the same level.

In a preferred embodiment of the present invention, the silicone oligomer Ps has a Tg of −70° C. or higher and 30° C. or lower, a side chain silicone functional group equivalent weight of 1000 to 20000 g/mol, and a weight average molecular weight Mw of 10000 or higher and 300000 or lower. can be

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 homopolymer having a glass transition temperature of −70° C. or more and 180° C. or less.

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

ここで、上記一般式（１），（２）中のＲ^３は水素またはメチルであり、Ｒ^４はメチル
基または１価の有機基であり、ｍおよびｎは０以上の整数である。 As the monomer S1 having a polyorganosiloxane skeleton, for example, the following general formula (1
) or (2) can be used. More specifically, X-22-174ASX, X-22 as one-end reactive silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.
-2426, X-22-2475, KF-2012, X-22-174BX, X-22-
2404 and the like. Monomer S1 having a polyorganosiloxane skeleton can be used alone or in combination of two or more.

Here, ^R3 in the general formulas (1) and (2) is hydrogen or methyl, ^R4 is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

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

Here, "functional group equivalent" means the weight of the main skeleton (for example, polydimethylsiloxane) bonded to one functional group. For the unit g/mol, 1 mol of functional group
is converted to The functional group equivalent of the monomer S1 having a polyorganosiloxane skeleton can be calculated, for example, from the spectral intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR). Calculation of the functional group equivalent (g/mol) of the monomer S1 having a polyorganosiloxane skeleton based on the spectral intensity of ¹ H-NMR is necessary based on a general structural analysis method for 1 H ^- NMR spectral analysis. If so, Japan Patent No. 595
1153 can be referred to.

In addition, 2 having different functional group equivalents as the monomer S1 having a polyorganosiloxane skeleton
When more than one type of monomer is used, an arithmetic mean 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 S11,
The functional group equivalent weight of the monomer S1 consisting of the monomers S12 . . . monomers S1n) can be calculated by the following formula.
Functional group equivalent of monomer S1 (g/mol) = (functional group equivalent of monomer S11 × amount of monomer S11 mixed + functional group equivalent of monomer S12 × amount of monomer S12 mixed + ... + functional group equivalent of monomer S1n × Amount of monomer S1n blended)/(Amount of monomer S11 blended + Amount of monomer S12 blended + ... + Amount of monomer S1n blended)

The content of the monomer S1 having a polyorganosiloxane skeleton may be, for example, 5% by weight or more with respect to the total monomer components for preparing the silicone oligomer Ps, and exhibits a better effect as an adhesive force increase retardant. It is preferably 10% by weight or more, and may be 15% by weight or more. In some aspects, the content of the monomer S1 may be, for example, 20% by weight or more. In addition, the content of the monomer S1 having a polyorganosiloxane skeleton is the silicone oligomer Ps from the viewpoint of polymerization reactivity and compatibility.
It is suitable to be 60% by weight or less with respect to the total monomer components for preparing 5
It may be 0% by weight or less, 40% by weight or less, or 30% by weight or less. When the content of the monomer S1 having a polyorganosiloxane skeleton is within the above range, it is easy to realize a pressure-sensitive adhesive sheet that achieves a high level of both initial low tackiness and increased tackiness during use (strong tackiness). Become.

(2) A monomer whose homopolymer has a glass transition temperature of −70° C. or more and 180° C. or less The silicone oligomer Ps of the present invention is a (meth)acrylic monomer or other Contains copolymerizable monomers. As a copolymerizable (meth)acrylic monomer or other copolymerizable monomer that can be used in the silicone oligomer Ps of the present invention, the glass transition temperature of the homopolymer is −
A monomer having a temperature of 70° C. or more and 180° C. or less can be used, and examples thereof include, but are not limited to, (meth)acrylic acid alkyl esters and (meth)acrylic acid esters having an alicyclic hydrocarbon group. (Meth)acrylic acid alkyl esters include methyl methacrylate (MMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2-EHMA), butyl acrylate (BA), and 2-ethylhexyl acrylate (2-EHA). , 2-((3-hydroxymethyl)-adamantan-1-yl)methoxy-2-oxoethyl methacrylate (2EHAMA), cyclopentyl (meth)acrylate, as (meth)acrylic acid esters having an alicyclic hydrocarbon group, Examples include, but are not limited to, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, and the like. In one embodiment of the invention, 2-((3-hydroxymethyl)-adamantan-1-yl)methoxy-2-oxoethyl methacrylate (2EH
AMA), and isobornyl methacrylate (IBXMA) as a monomer unit. Another embodiment of the present invention may contain at least one selected from dicyclopentanyl methacrylate, isobornyl methacrylate and cyclohexyl methacrylate as a monomer unit. These monomers can be used singly or in combination of two or more.

The amount of the (meth)acrylic acid alkyl ester and the (meth)acrylic acid ester having an alicyclic hydrocarbon group used is, for example, 10% by weight or more and 95% by weight of the total monomer components for preparing the silicone oligomer Ps. % by weight or less, 20% by weight or more9
It may be 5 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. good.

Other examples of the monomers that can be included together with the monomer S1 as monomer units constituting the silicone oligomer Ps include the carboxyl group-containing monomers and acid anhydride group-containing monomers that can be used in the alkyl (meth)acrylate (A). Monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, monomers having a nitrogen atom-containing ring, monomers having a succinimide skeleton, maleimides, itaconimides, (meth)acryl Acid aminoalkyls, vinyl esters, vinyl ethers, olefins, (meth)acrylic acid esters having aromatic hydrocarbon groups, heterocyclic (meth)acrylates, halogen atom-containing (meth)acrylates, terpene compound derivative alcohols Obtained (meth)acrylic acid esters and the like can be mentioned.

Still other examples of monomers that can be included together with monomer S1 as monomer units constituting silicone oligomer Ps include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate. Oxyalkylene di(meth)acrylates such as (meth)acrylates, propylene glycol di(meth)acrylates, dipropylene glycol di(meth)acrylates, and tripropylene glycol di(meth)acrylates; monomers having a polyoxyalkylene skeleton, such as polyethylene One end of the polyoxyalkylene chain such as glycol or polypropylene glycol has a polymerizable functional group such as a (meth)acryloyl group, vinyl group, or allyl group, and the other end has an ether structure (alkyl ether, aryl ether, aryl Alkyl ether, etc.); methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, (meth)acrylic acid Alkoxyalkyl (meth)acrylates such as ethoxypropyl; salts such as alkali metal (meth)acrylates; polyvalent (meth)acrylates such as trimethylolpropane tri(meth)acrylate esters: vinylidene chloride, (meth)acrylic Vinyl halide compounds such as acid-2-chloroethyl; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2
-Oxazoline group-containing monomers such as oxazoline and 2-isopropenyl-2-oxazoline; (meth)acryloylaziridine, aziridine group-containing monomers such as (meth)acrylic acid-2-aziridinylethyl; (meth)acrylic acid-2 -Hydroxyl-containing vinyl monomers such as hydroxyethyl, 2-hydroxypropyl (meth)acrylate, adducts of lactones and 2-hydroxyethyl (meth)acrylate; fluorine-substituted (meth)acrylic acid alkyl esters, etc. Fluorine-containing vinyl monomers; reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and monochlorovinyl acetate; vinyltrimethoxysilane, γ-(
meth) organosilicon-containing vinyl monomers such as acryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxysilane; macromonomers having a group; and the like. These can be copolymerized with the monomer S1 singly or in combination.

In the embodiment in which the monomer component used to prepare the silicone oligomer Ps contains the monomer S1 and the (meth)acrylic monomer, the monomer S
The total amount of 1 and the (meth)acrylic monomer may be, for example, 50% by weight or more.
0% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight
100% by weight may be sufficient.

The composition of the (meth)acrylic monomer contained in the monomer component can be set, for example, so that the glass transition temperature _Tm1 based on the composition of the (meth)acrylic monomer is higher than 0°C. Here, the glass transition temperature _Tm1 based on the composition of the (meth)acrylic monomer is defined by Fox's formula based on the composition of only the (meth)acrylic monomer among the monomer components used to prepare the silicone oligomer Ps. It refers to the required Tg. T _m1 is the (meta)
For only acrylic monomers, the above-mentioned Fox formula is applied, and the glass transition temperature of the homopolymer of each (meth)acrylic monomer and each (meth)acrylic monomer in the total amount of the (meth)acrylic monomer It can be calculated from the system monomer weight fraction. A silicone oligomer Ps having a glass transition temperature _Tm1 higher than 0° C. tends to suppress initial adhesive strength. In addition, by using a silicone oligomer Ps having a glass transition temperature _Tm1 higher than 0° C., it is easy to obtain a pressure-sensitive adhesive sheet having a high pressure-sensitive adhesive strength increase ratio.

In some embodiments, T _m1 may be −20° C. or higher, −10° C. or higher,
It may be 0° C. or higher, or 10° C. or higher. As _Tm1 increases, the adhesive strength at the initial stage of attachment is
In general, it tends to be better suppressed. In addition, T _m1 may be, for example, 90° C. or less,
It may be 80°C or lower, or 70°C or lower or lower than 70°C. A lower _Tm1 tends to facilitate an increase in adhesive strength by heating. The technology disclosed herein can be preferably practiced using a silicone oligomer Ps having a T _m1 in the range of, for example, -20°C to 90°C, or -10°C to 80°C, or 0°C to 70°C.

The silicone oligomer Ps can be produced, for example, by polymerizing the above-described monomers by known techniques such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization.

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

The amount of the chain transfer agent to be used is not particularly limited, but usually the chain transfer agent is used in an amount of 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight, per 100 parts by weight of the monomer. , more preferably 0.2 to 10 parts by weight. By adjusting the amount of the chain transfer agent added in this manner, a silicone oligomer Ps having a suitable molecular weight can be obtained. In addition, a chain transfer agent can be used individually by 1 type or in combination of 2 or more types.

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 with respect to 100 parts by weight of the (meth)acrylic polymer. In an embodiment of the present invention, the silicone oligomer Ps is preferably contained in an amount of 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. can be included in the 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 higher post-heating adhesive force can be obtained.

In addition, the silicone oligomer Ps as described above can preferably function as an adhesive force increase retardant by being blended in the adhesive layer. The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in a mode in which the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a base polymer and an adhesive strength increase retardant, and the adhesive strength increase retardant includes a silicone oligomer Ps. Here, the reason why the silicone oligomer Ps functions as an adhesive force increase retardant is that the initial adhesive force is suppressed by the silicone oligomer Ps present on the surface of the adhesive layer in the adhesive sheet from before attachment to the adherend to the initial stage of attachment. This is because the amount of silicone oligomer Ps present on the surface of the adhesive layer decreases due to the flow of the adhesive due to the passage of time or heating after application, and the silicone oligomer Ps becomes compatible with the adhesive, increasing the adhesive strength. Conceivable. Therefore, as the adhesive strength increase retarder in the technology disclosed herein, other materials capable of exhibiting the same kind of function can be used in place of the silicone oligomer Ps or in combination with the silicone oligomer Ps. A non-limiting example of such a material is a polymer having a polyoxyalkylene structure in its molecule (hereinafter also referred to as "polymer Po"). The polymer Po is, for example,
It may be a polymer containing monomer units derived from a monomer having a polyoxyalkylene skeleton. Specific examples include a homopolymer or a copolymer of two or more of the monomers having a polyoxyalkylene skeleton as described above, and one or more of the monomers having a polyoxyalkylene skeleton and others. (for example, (meth)acrylic monomer) can be used as the polymer Po. The amount of the monomer having a polyoxyalkylene skeleton used is not particularly limited, but for example, the amount of the monomer S1 used in the silicone oligomer Ps described above can also be applied to the amount of the monomer having a polyoxyalkylene skeleton used in the polymer Po. can be done. The amount of the polymer Po used in the pressure-sensitive adhesive layer is not particularly limited, but for example, the amount of the silicone oligomer Ps used with respect to the base polymer described above can also be applied to the amount of polymer Po used with respect to the base polymer. Alternatively, part of the amount of silicone oligomer Ps used relative to the base polymer described above (for example, about 5% to 95% by weight of the total amount of silicone oligomer Ps used, or about 15% to 85% by weight, or 30% % to 70% by weight) may be replaced with the polymer Po.

In one embodiment of the present invention, the melting temperature of the silicone oligomer Ps is -20 to 12
It may be 0°C. In another embodiment of the present invention, the melting temperature of the silicone oligomer Ps may be -10 to 90°C, 0 to 80°C.

<Other ingredients>
(crosslinking agent)
A cross-linking agent may be used in the pressure-sensitive adhesive layer disclosed herein for the purpose of cohesive force adjustment and the like. As the cross-linking agent, a commonly used cross-linking agent can be used. A melamine-based cross-linking agent, a metal chelate-based cross-linking agent, and the like can be mentioned. In particular, isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-based cross-linking agents can be preferably used. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

Specifically, examples of isocyanate-based cross-linking agents include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, and naphthalene. Examples include diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and adducts of these with polyols such as trimethylolpropane. Alternatively, a compound having at least one or more isocyanate groups and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth)acrylate, etc. can also be used as an isocyanate cross-linking agent. can be done. These are 1
The species can be used singly or in combination of two or more species.

Epoxy cross-linking agents include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane tri glycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m
-xylylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane. These can be used individually by 1 type or in combination of 2 or more types.

Metal chelate compounds include metal components such as aluminum, iron, tin, titanium, and nickel, and chelate components such as acetylene, methyl acetoacetate, and ethyl lactate. These can be used individually by 1 type or in combination of 2 or more types.

The amount of the cross-linking agent used can be, for example, 0.01 parts by weight or more, preferably 0.05 parts by weight or more, relative to 100 parts by weight of the base polymer. Higher cohesive strength tends to be obtained by increasing the amount of cross-linking agent used. In some embodiments, the amount of the cross-linking agent used relative to 100 parts by weight of the base polymer may be 0.1 parts by weight or more, 0.5 parts by weight or more, or 1 part by weight or more. good too. On the other hand, from the viewpoint of avoiding a decrease in tack due to an excessive improvement in cohesive strength, the amount of the cross-linking agent used relative to 100 parts by weight of the base polymer is
Usually, it is suitable to use 15 parts by weight or less, and it may be 10 parts by weight or less, or 5 parts by weight or less. In the pressure-sensitive adhesive composition containing a silicone oligomer Ps or other adhesive force increase retardant, the amount of the cross-linking agent used is not too large. It can also be advantageous from the viewpoint of good expression.

The technology disclosed in this specification can be preferably implemented in a mode using at least an isocyanate-based cross-linking agent as a cross-linking agent. From the viewpoint of facilitating the realization of a PSA sheet having a high cohesive strength after heating and a high ratio of increase in adhesive strength, in some embodiments, the amount of the isocyanate-based cross-linking agent used relative to 100 parts by weight of the base polymer is, for example, 5 parts by weight or less. and can be
It may be 3 parts by weight or less, 1 part by weight or less, 0.7 parts by weight or less, or 0.5 parts by weight or less.

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

(Silane coupling agent)
The pressure-sensitive adhesive layer disclosed herein can further contain a silane coupling agent. Durability can be improved by using a silane coupling agent. As the silane coupling agent, one having any appropriate functional group can be used.
Specific examples of functional groups include vinyl groups, epoxy groups, amino groups, mercapto groups, (meth)acryloxy groups, acetoacetyl groups, isocyanate groups, styryl groups, and polysulfide groups. Specifically, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, and vinyltributoxysilane; γ-glycidoxypropyltrimethoxysilane, γ
- epoxy group-containing silane coupling agents such as glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; γ-aminopropyltrimethoxysilane; Silane, N-β-
(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N-(1,
3-dimethylbutylidene)propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane; mercapto group-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane; p-styryl styryl group-containing silane coupling agents such as trimethoxysilane; (meth)acryl group-containing silane coupling agents such as γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane; 3-isocyanatopropyltriethoxysilane and polysulfide group-containing silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide. As the silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane are preferably used. can be done.

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

In addition, the pressure-sensitive adhesive layer in the technology disclosed herein may contain tackifiers, leveling agents, plasticizers, softeners, colorants (dyes, pigments, etc.), fillers, as long as the effects of the present invention are not significantly hindered. , an antistatic agent, an antiaging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, an antiseptic, and other known additives that can be used in pressure-sensitive adhesives.

(Formation of adhesive layer)
As a method of forming an adhesive layer, for example, a method of applying the adhesive composition to a release-treated separator or the like, drying and removing the polymerization solvent or the like to form an adhesive layer, and then transferring it to a polarizing film, or It is produced by a method of applying the pressure-sensitive adhesive composition to a polarizing film, removing the polymerization solvent and the like by drying, and forming a pressure-sensitive adhesive layer on the polarizing film. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

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

An appropriate drying time can be adopted as appropriate. The drying time is preferably 5 seconds to
20 minutes, more preferably 5 seconds to 10 minutes, particularly preferably 10 seconds to 5 minutes.

Moreover, an anchor layer can be formed on the surface of the polarizing film, or an adhesive layer can be formed after performing various types of 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.

Various methods are used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coater, etc. A method such as an extrusion coating method can be used.

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

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

Examples of materials constituting the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; porous materials such as paper, cloth, and nonwoven fabric; nets; foam sheets; A thin leaf body can be mentioned, but a plastic film is preferably used because of its excellent surface smoothness.

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

The thickness of the separator is usually about 5-200 μm, preferably about 5-100 μm. If necessary, the separator may be treated with silicone, fluorine, long-chain alkyl or fatty acid amide release agents, silica powder, etc. for release and antifouling treatment, coating type, kneading type, vapor deposition type Antistatic treatment, such as, can also be applied. In particular, by subjecting the surface of the separator to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the release property from the pressure-sensitive adhesive layer can be further enhanced.

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

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples shown below. All parts and percentages in each example are based on weight. All room temperature storage conditions not specified below are 23° C. and 65% RH.

The weight-average molecular weight Mw of each polymer below is determined by a GPC apparatus (manufactured by Tosoh Corporation, HLC-
8220 GPC) under the following conditions, and calculated by polystyrene conversion.
・Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)
・Sample injection volume: 10 μl
・ Eluent: THF ・ Flow rate: 0.6 ml / min
・Measurement temperature: 40°C

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

<Preparation of transparent protective film>
An acrylic resin film with a thickness of 40 μm and a moisture permeability of 60 g/m2/24 h (SP value of 22.
The easy-adhesion-treated surface of 2) was subjected to corona treatment before use.

<Active energy ray>
As an active energy ray,
・Ultraviolet irradiation device (gallium-filled metal halide lamp): Fusion UV Sy
Light HAMMER10 manufactured by stems, Inc.
・Bulb: V bulb ・Peak illuminance: 1600 mW/cm ² ,
・Integrated irradiation amount 1000/mJ/cm ² (wavelength 380 to 440 nm)
It was used. The UV illuminance was measured using a Sola-Check system manufactured by Solatell.

<Preparation of active energy ray-curable adhesive>
As the radical polymerizable compound (A), N-hydroxyethyl acrylamide (SP value 2
9.6, homopolymer Tg 123 ° C., manufactured by Kojin Co., Ltd.), 38.3 parts, and as the radically polymerizable compound (B), tripropylene glycol diacrylate (trade name: Aronix M-
220, SP value 19.0, homopolymer Tg 69 ° C., manufactured by Toagosei Co., Ltd.) 19.1 parts,
As the radically polymerizable compound (C), 38.3 parts of acryloylmorpholine (SP value 22.9, homopolymer Tg 150 ° C., manufactured by Kojin Co., Ltd.), and a photopolymerization initiator (trade name: KA
1.4 parts of YACURE DETX-S, diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd.) were mixed and stirred at 50° C. for 1 hour to obtain an active energy ray-curable adhesive.

<Preparation of polarizing film A>
After forming a urethane-based easy-adhesive layer with a thickness of 0.5 μm on the acrylic resin film, the active energy ray-curable adhesive is applied to the easy-adhesive layer with an MCD coater (manufactured by Fuji Machinery Co., Ltd.). (Cell shape: honeycomb, number of gravure roll lines: 1,000 lines/inch, rotation speed: 140%/line speed) was used to apply the adhesive layer so that the thickness of the adhesive layer was 0.5 μm. Then, the acrylic resin film was bonded to both surfaces of the polarizer as a transparent protective film on the viewing side and/on the panel side via the adhesive by means of a roll machine. After that, both sides of the laminated acrylic resin film were heated to 50° C. using an IR heater,
Both surfaces were irradiated with the ultraviolet rays to cure the active energy ray-curable adhesive. Furthermore, 7
After drying with hot air at 0° C. for 3 minutes, a polarizing film having transparent protective films on both sides of the polarizer was obtained (Table 1). The lamination line speed was 25 m/min.

<Preparation of adhesive>
(Preparation of polymer solution A)
To a reaction vessel equipped with a condenser, nitrogen inlet, thermometer and stirrer, 10 butyl acrylate was added.
0 parts, 5 parts acrylic acid, 0.075 parts 2-hydroxyethyl acrylate and 2,2'-
A solution was prepared by adding 0.3 parts of azobisisobutyronitrile together with ethyl acetate. Next, this solution was stirred while blowing nitrogen gas, and reacted at 60° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average Mw of 2,200,000. Further, an acrylic polymer solution A was obtained by adding ethyl acetate to the solution containing the acrylic polymer to adjust the solid content concentration to 30%.

As a crosslinking agent, 0.6 parts of a crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") based on a compound having an isocyanate group is added to 100 parts of the solid content of the acrylic polymer solution A. ), and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”) as a silane coupling agent.
and were blended in this order to prepare an adhesive polymer solution A.

(Preparation of polymer solution B)
94 parts of 2-ethylhexyl acrylate (2EHA), 6 parts of acrylic acid and 0.3 parts of 2,2′-azobisisobutyronitrile are placed in a reaction vessel equipped with a condenser, nitrogen inlet, thermometer and stirrer. Added with ethyl acetate to form a solution. Next, this solution was stirred while blowing nitrogen gas, and reacted at 60° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight Mw of 2,200,000. Furthermore, an acrylic polymer solution (
B) was obtained.

0.6 as a cross-linking agent with respect to 100 parts of the solid content of the acrylic polymer solution (B)
parts of a cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") mainly composed of a compound having an isocyanate group, and 0.075 parts of γ-glycidoxypropyltrimethoxy as a silane coupling agent. Silane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403
”) were blended in this order to prepare an adhesive polymer solution B.

Acrylic polymer solution (A) (polymer A) and acrylic polymer solution (B) (
The composition of polymer B) is shown in Table 2 below.

(Preparation of silicone oligomer A)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a condenser, and a dropping funnel,
100 parts of ethyl acetate, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), 2-
20 parts of ethylhexyl methacrylate (2EHMA), a polyorganosiloxane skeleton-containing methacrylate monomer having a functional group equivalent of 900 g/mol (trade name: X-22-174A
SX, manufactured by Shin-Etsu Chemical Co., Ltd.) 8.7 parts, a polyorganosiloxane skeleton-containing methacrylate monomer having a functional group equivalent of 4600 g / mol (trade name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.) 11.3 parts and a chain 0.2 part of methyl thioglycolate was added as a transfer agent. Then, after stirring at 70° C. for 1 hour under a nitrogen atmosphere, 2, as a thermal polymerization initiator,
After adding 0.2 parts of 2′-azobisisobutyronitrile and reacting at 70° C. for 2 hours,
0.1 part of 2,2′-azobisisobutyronitrile was added as a thermal polymerization initiator, followed by 8
The reaction was allowed to proceed at 0°C for 3 hours. Thus, a silicone oligomer solution was obtained. The weight average molecular weight Mw of this silicone oligomer was 18,000.

(Preparation of other silicone oligomers B to F)
Silicone oligomers B to F were prepared in the same manner as silicone oligomer A, except that the monomer composition and parts by weight were changed to those shown in Table 3.

(Preparation of adhesive solution)
One part of the silicone oligomer A was blended with the adhesive polymer solution A prepared above to prepare an acrylic adhesive solution used in Example 1. Similarly, using the adhesive polymer solutions and silicone oligomers shown in Table 4 below, acrylic adhesive solutions used in Examples 2 to 19 were prepared.

(Preparation of polarizing film with adhesive layer)
[Example 1] to [Example 19]
Next, the above acrylic pressure-sensitive adhesive solution is evenly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone release agent, dried in an air circulating constant temperature oven at 155° C. for 2 minutes, and separated into a separator film. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed on the surface of this. A separator having an adhesive layer is transferred to one side of the polarizing film,
A polarizing film with an adhesive layer was produced.

[Comparative Example 1]
In Comparative Example 1, a polarizing film with an adhesive layer was produced in the same manner as in Example 1, except that Silicone Oligomer A was omitted.

[Comparative Example 2] to [Comparative Example 5]
In Comparative Examples 2 to 5, an ether group-containing polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "Modified Silicone Oil KF-353") was used instead of Silicone Oligomer A, and the blending amount was changed as shown in Table 4. A polarizing film with an adhesive layer was produced in the same manner as in Example 1 except for the above.

[Reference example 1]
In Reference Example 1, in place of Silicone Oligomer A, another rework improver (manufactured by Kaneka Co., Ltd., product name "SAT10") was used, and the blending amount was changed as shown in Table 4. Then, a polarizing film with an adhesive layer was produced.

The polarizing films with pressure-sensitive adhesive layers obtained in Examples 1 to 19, Comparative Examples 1 to 5, and Reference Example 1 were evaluated as follows. Table 4 shows the results.

<Evaluation of durability>
Peel off the separator film of the polarizing film with adhesive layer (37 inches),
Using a laminator, it was adhered to non-alkaline glass (EG-XG, manufactured by Corning Co., Ltd.). Then, autoclave treatment was performed at 50° C. and 0.5 MPa for 15 minutes to completely adhere the polarizing film to the alkali-free glass. Next, each of these was placed in a heating oven (heating) at 80° C., 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 recognized at all.
B: Foaming was observed to the extent that it could not be visually confirmed.
C: Peeling was observed to the extent that it could not be visually confirmed.
D: Small foaming or peeling that can be visually confirmed was observed.
E: Clear foaming or peeling was observed.

<Evaluation of adhesive strength>
(1) Measurement of initial adhesive strength Under a standard environment of 23 ° C. and 50% RH, the produced polarizing film with an adhesive layer is vertically 120
A sample was cut into a size of 25 mm×25 mm. The sample was pressed against an alkali-free glass plate (manufactured by Corning, EG-XG) with a thickness of 0.7 mm by reciprocating a 2 kg roller once, and then the adhesive strength of the sample was measured. The adhesive strength was measured by using a tensile tester (Autograph SHIMAZU AG-1 1OKN) with a peeling angle of 90° and a peeling speed of 300mm/m.
It was determined by measuring the adhesive strength (N/25 mm, measurement length 80 mm) when peeled off at 1.5 in. The measurement was sampled 200 times at an interval of 1 time/0.5 s, and the average value was used as the measured value. Three specimens were used. Their average value is shown in the "2 kg roller" column of Table 4 as the initial adhesive strength. Based on the level of adhesive strength, the reworkability was judged according to the following criteria.
A: 4 N/25 mm or less, rework succeeds 90%.
B: More than 4 N/25 mm and 5 N/25 mm or less, rework succeeds 80% or more.
C: More than 5N/25mm and 6N/25mm or less, rework succeeds 70% or more.
D: More than 6N/25mm and 7N/25mm or less, rework succeeds 60% or more.
E: More than 7N/25mm, more than 40% failure of rework.

(2) Measurement of post-heating adhesive force A sample was obtained by cutting the produced polarizing film with an adhesive layer into a length of 120 mm and a width of 25 mm. The sample was placed on a non-alkali glass plate with a thickness of 0.7 mm (manufactured by Corning,
EG-XG) using a laminator, followed by autoclaving at 50° C. and 5 atm for 15 minutes to ensure complete adhesion, and then the adhesive strength of the sample was measured. The adhesive strength was measured using a tensile tester (Autograph SHIMAZU AG-1 1OKN) with a peel angle of 90.
°, adhesive strength when peeling off at a peeling speed of 300 mm / min (N / 25 mm, measurement length 80 m
It was obtained by measuring m). The measurement was sampled 200 times at an interval of 1 time/0.5 s, and the average value was used as the measured value. Three specimens were used. In Table 4, "60°C x 2h"
and "60°C x 24h" indicate adhesive strength after standing at 60°C for 2 hours and 24 hours, respectively.

As described above, according to the present invention, it is possible to provide a polarizing film with an adhesive layer having both high durability and reworkability.

The present invention includes the following aspects.
<1>
a polarizing film;
Adhesive layer
A polarizing film with an adhesive layer, comprising
The pressure-sensitive adhesive layer contains a base polymer and a silicone oligomer Ps,
The base polymer is a (meth)acrylic polymer,
The silicone oligomer Ps is contained in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer,
The silicone oligomer Ps has a Tg of −50° C. or higher and 100° C. or lower, a side chain silicone functional group equivalent weight of 1000 to 20000 g/mol, and a weight average molecular weight Mw of 10000 or higher and 300000 or lower.
Polarizing film with adhesive layer.
<2>
The pressure-sensitive adhesive layer-attached polarized light according to <1>, wherein 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° C. or more and 180° C. or less. film.
<3>
<1> or <2>, wherein the monomer unit of the base polymer contains 80% by weight or more of an alkyl (meth)acrylate (A) having a homopolymer glass transition temperature of −80° C. or higher and 0° C. or lower. A polarizing film with an adhesive layer.
<4>
<3>, the polarizing film with an adhesive layer.
<5>
The polarizing film with an adhesive layer according to any one of <1> to <4>, wherein the base polymer has a weight average molecular weight Mw of 500,000 to 2,500,000.
<6>
The pressure-sensitive adhesive layer-carrying polarizing film according to any one of <1> to <5>, wherein the silicone oligomer Ps has a melting temperature of -20 to 120°C.

REFERENCE SIGNS LIST 1 polarizer 2, 2' protective film 3 polarizing film 4 adhesive layer 5 separator 10 polarizing film with adhesive layer

Claims (6)

a polarizing film;
A polarizing film with an adhesive layer, comprising an adhesive layer,
The pressure-sensitive adhesive layer contains a base polymer and a silicone oligomer Ps,
The base polymer is a (meth)acrylic polymer containing a hydroxyl group-containing monomer as a monomer unit ,
The silicone oligomer Ps is contained in an amount of 1 to 5 parts by weight (excluding 1 to 2 parts by weight) with respect to 100 parts by weight of the (meth)acrylic polymer,
The silicone oligomer Ps has a Tg of −30 ° C. or higher and 70 ° C. or lower, a side chain silicone functional group equivalent weight of 1000 to 20000 g/mol, and a weight average molecular weight Mw of 10000 or higher and 300000 or lower.
Polarizing film with adhesive layer. The pressure-sensitive adhesive layer-attached polarized light according to claim 1, wherein 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° C. or more and 180° C. or less. film. 3. The pressure-sensitive adhesive according to claim 1, wherein the monomer unit of the base polymer contains 80% by weight or more of an alkyl (meth)acrylate (A) having a homopolymer glass transition temperature of −80° C. or higher and 0° C. or lower. Polarizing film with an agent layer. Further containing 0 to 20% by weight of at least one polar monomer (B) selected from the group consisting of carboxyl group-containing monomers (b1) and nitrogen-containing monomers (b2) as the monomer units of the base polymer. Item 4. The polarizing film with an adhesive layer according to item 3. The polarizing film with an adhesive layer according to any one of claims 1 to 4, wherein the base polymer has a weight average molecular weight Mw of 500,000 to 2,500,000. The pressure-sensitive adhesive layer-carrying polarizing film according to any one of claims 1 to 5, wherein the silicone oligomer Ps has a melting temperature of -20 to 120°C.

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