WO2010018795A1

WO2010018795A1 - Optical film with adhesive and optical laminate using same

Info

Publication number: WO2010018795A1
Application number: PCT/JP2009/064039
Authority: WO
Inventors: 流竹厚; 容演金; 智恵許; 陽介太田
Original assignee: 住友化学株式会社
Priority date: 2008-08-11
Filing date: 2009-08-07
Publication date: 2010-02-18
Also published as: TWI449766B; CN102119348A; JP2010066756A; TW201018718A; JP5354674B2; KR101597851B1; CN102119348B; KR20110045012A

Abstract

An adhesive layer (20) formed from a composition that contains (A), (B), and (C) is provided on an optical film (10) to produce an optical film with adhesive (25). (A) 100 parts by weight of an acrylic resin which is a copolymer of a monomer mixture that contains: (A-1) 55-94 wt% of a (meth)acrylic acid ester with formula (I) (I) (R1 is hydrogen or a methyl group, and R2 is a C1-14 alkyl or aralkyl), (A-2) 5-40 wt% of a (meth)acrylic acid ester having an alkoxyethyl group, such as acrylic acid 2-methoxyethyl, and (A-3) 0.1-5 wt% of an unsaturated monomer having a polar functional group. (B) 0.3-12 parts by weight of an ionic compound that has organic cations and is a solid at room temperature. (C) 0.1-5 parts by weight of a crosslinking agent.

Description

Optical film with adhesive and optical laminate using the same

The present invention relates to an optical film having an adhesive layer formed thereon. Examples of the optical film to be used in the present invention include a polarizing plate and a retardation film. The present invention also relates to an optical laminate for liquid crystal display using an optical film in which this pressure-sensitive adhesive layer is formed.

A polarizing plate is mounted on a liquid crystal display device and is widely used. A transparent protective film is laminated on both surfaces of a polarizer, and an adhesive layer is formed on the surface of at least one protective film. It is distributed in the state where the release film is stuck to. In addition, a retardation film may be laminated on a polarizing plate in which a protective film is bonded to both surfaces of the polarizer to form an elliptical polarizing plate, and an adhesive layer / release film may be attached to the retardation film side. is there. Furthermore, an adhesive layer / release film may be stuck on the surface of the retardation film. Prior to bonding to the liquid crystal cell, the release film is peeled off from these polarizing plate, elliptical polarizing plate, retardation film, etc., and bonded to the liquid crystal cell via the exposed adhesive layer. Such a polarizing plate, elliptical polarizing plate, or retardation film generates static electricity when the release film is peeled off and bonded to a liquid crystal cell, and therefore development of a countermeasure for the prevention is desired.

As one of countermeasures, in JP-A-6-313807 (Patent Document 1), in a polarizing plate in which a protective film is laminated on the surface of a polarizer film and an adhesive layer is provided on the surface of the protective film, As an adhesive, it has been proposed to use an ion conductive composition comprising an electrolyte salt and an organopolysiloxane and a composition containing an acrylic copolymer. By using such a pressure-sensitive adhesive, although antistatic properties are exhibited, its performance is not necessarily sufficient, and it cannot be said that adhesion durability is sufficient.

On the other hand, Japanese Patent Application Publication No. 2004-536940 (Patent Document 2) discloses that an organic salt-based antistatic agent is blended with a pressure-sensitive adhesive (adhesive) to impart antistatic properties to the adhesive. It is disclosed. Japanese Patent Application Laid-Open No. 2004-114665 (Patent Document 3) includes a salt made of a quaternary ammonium cation having a total carbon number of 4 to 20 and a fluorine atom-containing anion in an adhesive or the like, thereby improving antistatic properties. It is described to give. Furthermore, Japanese Patent Application Laid-Open No. 2006-307238 (Patent Document 4) describes that an adhesive contains an ionic liquid that becomes liquid at room temperature (25 ° C.) to prevent charging, and Japanese Patent Application Laid-Open No. 2006-16595. (Patent Document 5) describes an antistatic pressure-sensitive adhesive composition comprising an ionic liquid, an ethylene oxide-containing compound, and a polymer having a glass transition temperature Tg of 0 ° C. or less as a base polymer. . However, when a polarizing plate coated with an adhesive containing an ionic liquid disclosed in these documents is left for a long time, the antistatic performance remains deteriorated due to a change with time. Since the distribution and storage period of a general polarizing plate is about six months at the maximum from the production, it is required to maintain the antistatic performance until the customer uses it. In particular, in an in-plane (Switching: IPS) mode liquid crystal cell, high antistatic properties are often required for optical films.

In addition, the optical film with an adhesive as described above is bonded to a liquid crystal cell on the adhesive layer side to form a liquid crystal display device. In this state, the optical film is placed under high temperature or high temperature and high humidity conditions, or heated. When cooling is repeated, foaming occurs in the pressure-sensitive adhesive layer as the optical film changes in size, or it floats or peels between the optical film and the pressure-sensitive adhesive layer, or between the pressure-sensitive adhesive layer and the liquid crystal cell glass. Therefore, it is also required to have excellent durability without causing such problems. In addition, when exposed to high temperatures, the distribution of residual stress acting on the optical film becomes non-uniform and stress concentration occurs on the outer periphery of the optical film, resulting in a phenomenon called whitening that causes the outer periphery to become whitish when displaying black. In some cases, color unevenness may occur, and suppression of such white spots and color unevenness is also required. Furthermore, when there is a deficiency when bonding an optical film with an adhesive to a liquid crystal cell, the optical film will be peeled off once and then a new film will be pasted again. A so-called rework property is also required in which the pressure-sensitive adhesive layer is peeled off along with the optical film, and the pressure-sensitive adhesive does not remain on the cell glass and no fogging occurs.

Japanese Patent Application Laid-Open No. 2005-206776 (Patent Document 6) discloses an antistatic acrylic pressure-sensitive adhesive containing an acrylic copolymer having an alkylene oxide chain such as a hydroxyl group and an ethylene oxide chain in the side chain, an ionic compound, and a curing agent. It is disclosed. However, the ionic compound used in Patent Document 6 is only an ionic compound having an inorganic cation such as a Li salt, and such an ionic compound has a problem of poor compatibility with the base polymer of the pressure-sensitive adhesive. It was.

JP-A-6-313807 JP-T-2004-536940 JP 2004-114665 A JP 2006-307238 A JP 2006-16595 A Japanese Patent Laid-Open No. 2005-206776

An object of the present invention is to provide an optical film with a pressure-sensitive adhesive provided with a pressure-sensitive adhesive layer on the surface of the optical film, which is provided with a high antistatic property, the antistatic property hardly changes with time, and is excellent in durability. There is to do. As a result of intensive studies to solve such problems, the present inventors blended a specific acrylic resin with an ionic compound that is solid at room temperature (25 ° C.) and a crosslinking agent, and this composition. It was found that an optical film with an adhesive excellent in antistatic property, antistatic property change with time and durability can be obtained by providing as a pressure-sensitive adhesive layer on the surface of the optical film.

That is, according to the present invention, the pressure-sensitive adhesive layer is formed on at least one surface of the optical film, and the pressure-sensitive adhesive layer contains the following components (A), (B), and (C). An optical film with a pressure-sensitive adhesive formed from the above is provided.
(A) (A-1) The following formula (I)

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group)
(Meth) acrylic acid ester 55 to 94% by weight represented by
(A-2) The following formula (II)

(Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 10)
(Meth) acrylic acid ester represented by the formula (hereinafter sometimes referred to as “ether-type (meth) acrylic acid ester”) 5 to 40% by weight, and
(A-3) 0.1 to 5% by weight of an unsaturated monomer having a polar functional group
100 parts by weight of an acrylic resin which is a copolymer obtained from a monomer mixture containing
(B) 0.3 to 12 parts by weight of an ionic compound having an organic cation and being solid at room temperature, and (C) 0.1 to 5 parts by weight of a crosslinking agent.

Thus, while providing an antistatic property to the adhesive layer formed from the adhesive composition containing the specific acrylic resin (A) prescribed | regulated by this invention, it aims at suppression of the time-dependent change of the antistatic property. As an antistatic agent for this purpose, it has been found that an ionic compound (B) that is solid at room temperature (25 ° C.) is particularly effective.

Moreover, according to the present invention, there is also provided an optical laminate in which the above-mentioned optical film with an adhesive is laminated on a glass substrate on the adhesive layer side.

The optical film with a pressure-sensitive adhesive of the present invention can effectively suppress charging of the optical member.
In addition, by containing an ionic compound that has an organic cation and is solid at room temperature in the pressure-sensitive adhesive composition, it is possible to maintain the initial antistatic performance even after storage for a long time. It is.

Moreover, since optical defects caused by uneven stress distribution are prevented, white spots are suppressed. In addition, if there is any inconvenience after laminating the optical film with adhesive once on the glass substrate, even if the optical film is peeled off from the glass substrate together with the adhesive, adhesive residue or Clouding is less likely to occur, and it can be used again as a glass substrate, resulting in excellent reworkability.

This optical film with an adhesive gives, for example, an optical laminate for liquid crystal display by being laminated on a glass substrate of a liquid crystal cell. In this optical laminate, the pressure-sensitive adhesive layer absorbs and relaxes stress caused by dimensional changes of the optical film and glass substrate under wet heat conditions, so that local stress concentration is reduced and the pressure-sensitive adhesive layer floats on the glass substrate. And peeling are suppressed.

It is a cross-sectional schematic diagram which shows the example of the suitable layer structure of the optical laminated body which concerns on this invention.

Hereinafter, the present invention will be described in detail. The optical film with a pressure-sensitive adhesive of the present invention is one in which a pressure-sensitive adhesive layer is formed on at least one side of the optical film,
(A) acrylic resin,
(B) an ionic compound having an organic cation and being solid at room temperature, and
(C) It is formed from a composition containing a crosslinking agent. First, each component which comprises an adhesive composition is demonstrated.

[Acrylic resin (A)]
In the optical film with the pressure-sensitive adhesive of the present invention, the acrylic resin (A) used for the pressure-sensitive adhesive layer is mainly composed of a structural unit derived from the (meth) acrylic acid ester represented by the formula (I). Specifically, in addition to the structural unit derived from the (meth) acrylic acid ester, a structural unit derived from the ether type (meth) acrylic acid ester represented by the formula (II), a free carboxyl group, a hydroxyl group, It includes a structural unit derived from a monomer having a polar functional group such as an amino group or a heterocyclic group including an epoxy ring, preferably a (meth) acrylic acid compound having a polar functional group. Here, (meth) acrylic acid means that either acrylic acid or methacrylic acid may be used, and “(meth)” when referred to as (meth) acrylate or the like has the same meaning.

In the formula (I), which is the main structural unit of the acrylic resin (A), R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group or an aralkyl group having 1 to 14 carbon atoms, preferably an alkyl group. is there.

Of the (meth) acrylic acid ester (A-1) represented by the formula (I), those in which R ₂ is an alkyl group, specifically, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid linear alkyl acrylates such as n-butyl, n-octyl acrylate and lauryl acrylate; branched alkyl acrylates such as isobutyl acrylate, 2-ethylhexyl acrylate and isooctyl acrylate; Linear alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, lauryl methacrylate; isobutyl methacrylate, 2-ethylhexyl methacrylate, methacryl Branched media such as isooctyl acid Such as acrylic acid alkyl ester is exemplified. Specific examples of the (meth) acrylic acid ester represented by the formula (I) when R ₂ is an aralkyl group include benzyl acrylate and benzyl methacrylate. These (meth) acrylic acid esters (A-1) can be used alone or in combination with a plurality of different ones.

Among these, n-butyl acrylate is preferable. Specifically, among all the monomers constituting the acrylic resin (A), n-butyl acrylate is 50% by weight or more, and the above-described one is used. It is preferable to use it so as to satisfy the regulations regarding (meth) acrylic acid ester (A-1).

The ether type (meth) acrylic acid ester (A-2) is represented by the above formula (II). Specific examples of the ether type (meth) acrylic acid ester (A-2) represented by the formula (II) include 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-methoxy-2-ethoxyethyl acrylate And 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-methoxy-2-ethoxyethyl methacrylate and the like. These ether type (meth) acrylic acid esters (A-2) can also be used alone or in combination with a plurality of different types.

Of these, 2-methoxyethyl acrylate is preferably used as one of the (meth) acrylic acid esters (A-2) constituting the acrylic resin (A).

Examples of the unsaturated monomer (A-3) having a polar functional group include monomers having a free carboxyl group such as acrylic acid, methacrylic acid, β-carboxyethyl acrylate; (meth) acrylic acid 2- Monomers having a hydroxyl group such as hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 2- or 3-chloro-2-hydroxypropyl (meth) acrylate, and diethylene glycol mono (meth) acrylate; acryloylmorpholine, vinyl Caprolactam, N-vinyl-2-pyrrolidone, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2,5-dihydrofuran Like Monomers having a heterocyclic group; N, such as N- dimethylaminoethyl (meth) acrylate, and the like monomers having different amino group and heterocyclic. These unsaturated monomers (A-3) having a polar functional group may be used alone or in a plurality of different types.

Among these, the polar functional group of the unsaturated monomer (A-3) is preferably a free carboxyl group, a hydroxyl group, an amino group, or an epoxy ring. In particular, a monomer having a hydroxyl group is preferably used as one of the polar functional group-containing monomers (A-3) constituting the acrylic resin (A). In addition to the monomer having a hydroxyl group, it is also effective to use a monomer having another polar functional group, for example, a monomer having a free carboxyl group.

The acrylic resin (A) used for the pressure-sensitive adhesive layer is 55 to 94% by weight of the (meth) acrylic acid ester (A-1) represented by the formula (I) and the ether type represented by the formula (II) ( A copolymer obtained from a monomer mixture containing 5 to 40% by weight of (meth) acrylic acid ester (A-2) and 0.1 to 5% by weight of unsaturated monomer (A-3) having a polar functional group. It is a polymer. In this copolymer, the structural unit derived from the (meth) acrylic acid ester (A-1) represented by the formula (I) is preferably 70 to 94% by weight, more preferably 72 to 94% by weight, The structural unit derived from the ether type (meth) acrylic acid ester (A-2) represented by 7) to 25% by weight and the structural unit derived from the unsaturated monomer (A-3) having a polar functional group Is 0.5 to 3% by weight.

The acrylic resin (A) used in the present invention comprises the above-described (meth) acrylic acid ester of the formula (I), an ether type (meth) acrylic acid ester of the formula (II) and an unsaturated group having a polar functional group. A structural unit derived from a monomer other than the monomer may be included. Examples of these include structural units derived from (meth) acrylic acid esters having an alicyclic structure in the molecule, structural units derived from styrene monomers, structural units derived from vinyl monomers, molecules Examples thereof include a structural unit derived from a monomer having a plurality of (meth) acryloyl groups.

The alicyclic structure is a cycloparaffin structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the acrylate ester having an alicyclic structure include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, tert-butyl acrylate Examples of methacrylic acid esters having an alicyclic structure include isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, methacrylic acid, and the like, such as cyclohexyl, α-ethoxyacrylate cyclohexyl, and cyclohexyl phenyl acrylate. Such as cyclododecyl, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate, cyclohexyl phenyl methacrylate And so on.

Examples of styrenic monomers include styrene, alkyl styrene such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene. Halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; and nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like.

Examples of vinyl monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; vinylidene chloride And vinylidene halides such as: nitrogen-containing aromatic vinyl such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene and chloroprene; and acrylonitrile and methacrylonitrile.

Examples of monomers having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol. 2 (meth) in the molecule, such as di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate Monomers having an acryloyl group; monomers having three (meth) acryloyl groups in the molecule, such as trimethylolpropane tri (meth) acrylate, can be mentioned.

Monomers other than the (meth) acrylic acid ester of the formula (I), the ether type (meth) acrylic acid ester of the formula (II) and the unsaturated monomer having a polar functional group are each alone or two kinds These can be used in combination. In the acrylic resin (A) used for the pressure-sensitive adhesive, a unit other than the (meth) acrylic acid ester of the formula (I), the ether type (meth) acrylic acid ester of the formula (II) and a monomer having a polar functional group. The structural unit derived from the monomer is usually contained in a proportion of 0 to 20 parts by weight, preferably 0 to 10 parts by weight, based on 100 parts by weight of the nonvolatile content of the resin.

The active ingredient of the pressure-sensitive adhesive is a structure derived from a monomer having a (meth) acrylate ester of the formula (I), an ether type (meth) acrylate ester of the formula (II) and a polar functional group as described above. Two or more kinds of acrylic resins containing units may be included. Further, the acrylic resin is mixed with an acrylic resin different from the acrylic resin, specifically, for example, an acrylic resin having a structural unit derived from the (meth) acrylic ester of the formula (I) and containing no polar functional group. It may be what you did. An acrylic resin containing a structural unit derived from a monomer having a polar functional group, the main component of which is a structural unit derived from the (meth) acrylic acid ester of the formula (I) is 60% by weight or more of the whole acrylic resin. Further, it is preferably 80% by weight or more.

An acrylic resin which is a copolymer obtained from a monomer mixture containing a (meth) acrylic acid ester of the formula (I), an ether type (meth) acrylic acid ester of the formula (II) and a monomer having a polar functional group It is preferable that the weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography (GPC) is in the range of 1 million to 2 million. When the weight average molecular weight in terms of standard polystyrene is 1,000,000 or more, the adhesiveness under high temperature and high humidity is improved, and the possibility of occurrence of floating or peeling between the glass substrate and the pressure-sensitive adhesive layer is reduced. And reworkability tends to be improved. In addition, when the weight average molecular weight is 2 million or less, even if the dimension of the optical film bonded to the pressure-sensitive adhesive layer changes, the pressure-sensitive adhesive layer fluctuates following the dimensional change. This is preferable because there is no difference between the brightness of the peripheral edge and the brightness of the center, and white spots and color unevenness tend to be suppressed. The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually in the range of about 2 to 10.

The acrylic resin (A) preferably has a glass transition temperature in the range of −10 to −60 ° C. in order to develop adhesiveness. The glass transition temperature of the resin can generally be measured with a differential scanning calorimeter.

This acrylic resin can be composed only of a relatively high molecular weight as described above, or it can be composed of a mixture of an acrylic resin different from the acrylic resin in addition to the acrylic resin. Examples of the acrylic resin that can be used as a mixture include those having a structural unit derived from the (meth) acrylic acid ester represented by the formula (I) as a main component and having a weight average molecular weight in the range of 50,000 to 300,000. Can be mentioned.

Acrylic resin (a mixture of both when two or more types are combined) is a solution prepared by dissolving it in ethyl acetate to a non-volatile content of 20% by weight, at 25 ° C., 20 Pa · s or less, and further 0.1 to 7 Pa. -It is preferable to show the viscosity of s. If the viscosity at this time is 20 Pa · s or less, the adhesiveness under high temperature and high humidity is improved, and the possibility of floating or peeling between the glass substrate and the pressure-sensitive adhesive layer tends to be reduced. Moreover, it is preferable because reworkability tends to be improved. Viscosity can be measured with a Brookfield viscometer.

The acrylic resin constituting the pressure-sensitive adhesive layer can be produced by various known methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method. In the production of this acrylic resin, a polymerization initiator is usually used. The polymerization initiator is used in an amount of about 0.001 to 5 parts by weight with respect to a total of 100 parts by weight of all monomers used for the production of the acrylic resin.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of thermal polymerization initiators include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis (2-methylpropio) Azo) compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide , Diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxy Organic peroxides such as neodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide Can do. A redox initiator using a peroxide and a reducing agent in combination can also be used as the polymerization initiator.

As the method for producing the acrylic resin, the solution polymerization method is preferable among the methods shown above. A specific example of the solution polymerization method will be described below. A desired monomer and an organic solvent are mixed, and a thermal polymerization initiator is added under a nitrogen atmosphere, and the temperature is about 40 to 90 ° C., preferably 60 to 80 ° C. An example is a method of stirring at about 0 ° C. for about 3 to 10 hours. In order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state dissolved in an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, and methyl isobutyl ketone. Ketones such as can be used.

[Ionic compound (B)]
In the present invention, in addition to the acrylic resin (A) as described above, an ionic compound (B) that is solid at room temperature (25 ° C.) is used as an antistatic agent. This ionic compound (B) has an organic cation. Such ionic compounds that are solid at room temperature may be referred to herein as ionic solids.

The cation component constituting the ionic compound (B) is not particularly limited as long as it is an organic cation satisfying that it becomes an ionic solid. For example, imidazolium cation, pyridinium cation, ammonium cation, sulfonium cation, phosphonium cation, etc. are mentioned, but when used in the adhesive layer of an optical film, it is difficult to be charged when peeling the release film provided on it. From the viewpoint, a pyridinium cation and an imidazolium cation are preferable.

On the other hand, in the ionic compound (B), the anion component serving as the counter ion of the cation component is not particularly limited as long as it satisfies that it becomes an ionic solid, and may be an inorganic anion, Organic anions may be used, and examples include the following.

Chloride anion [Cl ⁻ ],
Bromide anion [Br ⁻ ],
Iodide anion [I ⁻ ],
Tetrachloroaluminate anion [AlCl ₄ ⁻ ],
Heptachlorodialuminate anion [Al ₂ Cl ₇ ⁻ ],
Tetrafluoroborate anion [BF ₄ ⁻ ],
Hexafluorophosphate anion [PF ₆ ⁻ ],
Perchlorate anion [ClO ₄ ⁻ ],
Nitrate anion [NO ₃ ⁻ ],
Acetate anion [CH ₃ COO ⁻ ],
Trifluoroacetate anion [CF ₃ COO ⁻ ],
Methanesulfonate anion [CH ₃ SO ₃ ⁻ ],
Trifluoromethanesulfonate anion [CF ₃ SO ₃ ⁻ ],
p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ⁻ ],
Bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ],
Tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C ⁻ ], hexafluoroarsenate anion [AsF ₆ ⁻ ],
Hexafluoroantimonate anion [SbF ₆ ⁻ ],
Hexafluoroniobate anion [NbF ₆ ⁻ ],
Hexafluorotantalate anion [TaF ₆ ⁻ ],
Dimethyl phosphinate anion [(CH ₃ ) ₂ POO ⁻ ],
(Poly) hydrofluorofluoride anion [F (HF) _n ⁻ ] (n is about 1 to 3), dicyanamide anion [(CN) ₂ N ⁻ ],
Thiocyan anion [SCN ⁻ ],
Perfluorobutanesulfonate anion [C ₄ F ₉ SO ₃ ⁻ ],
Bis (pentafluoroethanesulfonyl) imide anion [(C ₂ F ₅ SO ₂ ) ₂ N ⁻ ], perfluorobutanoate anion [C ₃ F ₇ COO ⁻ ],
(Trifluoromethanesulfonyl) (trifluoromethanecarbonyl) imide anion [(CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ ] and the like.

Among these, an anion component containing a fluorine atom is preferably used because it gives an ionic solid excellent in antistatic performance, and a hexafluorophosphate anion or a bis (trifluoromethanesulfonyl) imide anion is particularly preferable.

Specific examples of the ionic solid used in the present invention can be appropriately selected from the combination of the cation component and the anion component. Specific examples of the compound that is a combination of a cation component and an anion component include the following.

N-hexylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-butyl-4-methylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-butyl-N-methylpyrrolidinium hexafluorophosphate,
1-ethyl-3-methylimidazolium hexafluorophosphate,
1-ethyl-3-methylimidazolium p-toluenesulfonate,
1-butyl-3-methylimidazolium methanesulfonate,
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium p-toluenesulfonate,
Tributylmethylammonium bis (trifluoromethanesulfonyl) imide,
(2-hydroxyethyl) trimethylammonium dimethylphosphinate and the like.

Such ionic solids can be used alone or in combination of two or more. Examples of ionic solids are not limited to the materials listed above.

As described above, the ionic compound (B) that is solid at room temperature imparts antistatic properties to the pressure-sensitive adhesive layer formed from the composition containing the acrylic resin (A) and maintains various physical properties as a pressure-sensitive adhesive. It is effective in. In particular, compared with the case of using an ionic compound that is liquid at room temperature, the antistatic performance can be maintained for a long period of time. From the viewpoint of such antistatic long-term stability, the ionic compound (B) preferably has a melting point of 30 ° C. or higher, more preferably 35 ° C. or higher. On the other hand, when the melting point is too high, the compatibility with the acrylic resin (A) is deteriorated, so that it preferably has a melting point of 90 ° C. or lower, more preferably 80 ° C. or lower. The molecular weight of the ionic compound (B) is not particularly limited, but for example, the molecular weight is preferably 700 or less, and more preferably 500 or less.

The ionic compound (B) is contained in a proportion of 0.3 to 12 parts by weight with respect to 100 parts by weight of the nonvolatile content of the acrylic resin (A). When the ionic compound (B) is contained in an amount of 0.3 part by weight or more with respect to 100 parts by weight of the nonvolatile content of the acrylic resin (A), the antistatic performance is improved, and the amount is 12 parts by weight or less. It is preferable because durability is easy to maintain. The amount of the ionic compound (B) with respect to 100 parts by weight of the nonvolatile content of the acrylic resin (A) is preferably 0.5 parts by weight or more and 5 parts by weight or less.

[Crosslinking agent (C)]
A crosslinking agent (C) is further blended into the acrylic resin (A) and the ionic compound (B) as described above to obtain a pressure-sensitive adhesive composition. The crosslinking agent (C) is a compound having in the molecule at least two functional groups capable of crosslinking with a structural unit derived from the unsaturated monomer (A-3) having a polar functional group in the acrylic resin (A). Specifically, an isocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound and the like are exemplified.

Isocyanate compounds are compounds having at least two isocyanato groups (—NCO) in the molecule, such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. In addition, adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and those obtained by converting isocyanate compounds into dimers, trimers, and the like can also be used as crosslinking agents for pressure-sensitive adhesives. Two or more isocyanate compounds can be mixed and used.

The epoxy compound is a compound having at least two epoxy groups in the molecule, for example, bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether. 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis ( N, N-diglycidylaminomethyl) cyclohexane and the like. Two or more types of epoxy compounds can be mixed and used.

Examples of the metal chelate compound include compounds in which acetylacetone or ethyl acetoacetate is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium. Can be mentioned.

An aziridine-based compound is a compound having at least two 3-membered ring skeletons composed of one nitrogen atom and two carbon atoms, also called ethyleneimine, for example, diphenylmethane-4,4′-bis ( 1-aziridinecarboxamide), toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1- (2-methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene -1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and the like.

Among these crosslinking agents, isocyanate compounds, especially xylylene diisocyanate, tolylene diisocyanate or hexamethylene diisocyanate, or adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and isocyanate compounds A dimer, trimer or the like, or a mixture of these isocyanate compounds is preferably used. In particular, when the polar functional group-containing unsaturated monomer (A-3) has a polar functional group selected from a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring, as at least one of the crosslinking agent (C), It is preferable to use an isocyanate compound. Examples of suitable isocyanate compounds include tolylene diisocyanate, adducts obtained by reacting tolylene diisocyanate with polyols, tolylene diisocyanate dimers, and tolylene diisocyanate trimers, hexamethylene diisocyanate, and hexamethylene diisocyanate. Examples include adducts reacted with polyols, dimers of hexamethylene diisocyanate, and trimers of hexamethylene diisocyanate.

The crosslinking agent (C) is blended at a ratio of 0.1 to 5 parts by weight, preferably about 0.2 to 3 parts by weight, with respect to 100 parts by weight of the acrylic resin (A). The amount of the crosslinking agent (C) relative to 100 parts by weight of the acrylic resin (A) is preferably 0.1 parts by weight or more because the durability of the pressure-sensitive adhesive layer tends to be improved, and is 5 parts by weight or less. And, when the optical film with a pressure-sensitive adhesive is applied to a liquid crystal display device, white spots are not noticeable.

[Other components constituting the pressure-sensitive adhesive composition]
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer in the present invention preferably contains a silane-based compound (D) in order to improve the adhesion between the pressure-sensitive adhesive layer and the glass substrate. It is preferable to contain the silane compound (D) in the acrylic resin before blending the agent.

Examples of the silane compound (D) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy (Cyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrime Kishishiran, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethyl silane, such as 3-glycidoxypropyl ethoxy dimethyl silane. Two or more silane compounds (D) may be used.

The silane compound (D) may be of a silicone oligomer type. Examples of the silicone oligomer in the form of a copolymer include the following.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,
A mercaptopropyl group-containing copolymer, such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;
Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,
Mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,
A copolymer containing a mercaptomethyl group, such as a mercaptomethyltriethoxysilane-tetraethoxysilane copolymer;
3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Copolymers containing methacryloyloxypropyl groups, such as 3-methacryloxyyl propylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
Vinyltrimethoxysilane-tetramethoxysilane copolymer,
Vinyltrimethoxysilane-tetraethoxysilane copolymer,
Vinyltriethoxysilane-tetramethoxysilane copolymer,
Vinyltriethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetramethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldiethoxysilane-tetramethoxysilane copolymer,
A vinyl group-containing copolymer, such as vinylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-aminopropyltriethoxysilane-tetramethoxysilane copolymer,
3-aminopropyltriethoxysilane-tetraethoxysilane copolymer,
3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Amino group-containing copolymers such as 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

These silane compounds (D) are often liquids. The compounding amount of the silane compound in the pressure-sensitive adhesive composition is usually about 0.01 to 10 parts by weight with respect to 100 parts by weight of the nonvolatile content of the acrylic resin (A) (the total weight when two or more kinds are used). The ratio is preferably 0.03 to 1 part by weight. It is preferable that the amount of the silane compound with respect to 100 parts by weight of the acrylic resin is 0.01 parts by weight or more, particularly 0.03 parts by weight or more because adhesion between the pressure-sensitive adhesive layer and the glass substrate is improved. Moreover, it is preferable for the amount to be 10 parts by weight or less, particularly 1 part by weight or less, because the silane compound tends to be suppressed from bleeding out from the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition described above may further contain a crosslinking catalyst, weathering stabilizer, tackifier, plasticizer, softener, dye, pigment, inorganic filler, resin other than the acrylic resin (A), and the like. It is also useful to blend an ultraviolet curable compound into the pressure-sensitive adhesive composition and to cure it by irradiating with ultraviolet rays after forming the pressure-sensitive adhesive layer to form a harder pressure-sensitive adhesive layer. Among them, if a crosslinking catalyst is blended with the crosslinking agent in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer can be prepared by aging in a short time, and in the resulting resin film with a pressure-sensitive adhesive, between the resin film and the pressure-sensitive adhesive layer. It is possible to suppress the occurrence of floating or peeling or foaming in the pressure-sensitive adhesive layer, and the reworkability may be further improved. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin. When an amine compound is blended in the pressure-sensitive adhesive composition as a crosslinking catalyst, an isocyanate compound is suitable as the crosslinking agent.

These components constituting the pressure-sensitive adhesive composition are coated on a suitable base material in a state dissolved in a solvent and dried to form a pressure-sensitive adhesive layer.

[Optical film with adhesive]
The optical film with a pressure-sensitive adhesive of the present invention is obtained by providing a pressure-sensitive adhesive layer formed of the above pressure-sensitive adhesive composition on at least one surface of an optical film. The optical film used here is a film having optical characteristics, and examples thereof include a polarizing plate and a retardation film.

A polarizing plate is an optical film having a function of emitting polarized light with respect to incident light such as natural light. The polarizing plate absorbs linearly polarized light having a vibrating surface in a certain direction and reflects linearly polarized light having a vibrating surface in a certain direction, and reflects linearly polarized light having a vibrating surface in a certain direction. There are a polarizing separation film having a property of transmitting linearly polarized light having a vibration plane orthogonal to the polarizing plate, an elliptically polarizing plate in which a polarizing plate and a retardation film described later are laminated. As a suitable specific example of a polarizing plate, particularly a linearly polarizing film (sometimes called a polarizer or a polarizer film), a dichroic dye such as iodine or a dichroic dye is added to a uniaxially stretched polyvinyl alcohol resin film. Are adsorbed and oriented.

The retardation film is an optical film exhibiting optical anisotropy, for example, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, cyclic polyolefin, polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride. / Stretched film obtained by stretching a polymer film made of polymethyl methacrylate, liquid crystal polyester, acetylcellulose, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, etc. by about 1.01 to 6 times. It is done. Among these, a polymer film obtained by uniaxially or biaxially stretching a polycarbonate film or a cyclic polyolefin film is preferable. Although there exist what is called a uniaxial phase difference film, a wide viewing angle phase difference film, a low photoelasticity phase difference film, etc., it is applicable to all.

Also, a film that exhibits optical anisotropy by applying and orienting a liquid crystalline compound and a film that exhibits optical anisotropy by applying an inorganic layered compound can be used as the retardation film. Such retardation films include what are called temperature-compensated retardation films, and films with a twisted orientation of rod-like liquid crystals sold under the trade name “LC film” by Nippon Oil Corporation. Also, a film with a tilted orientation of a rod-shaped liquid crystal sold under the trade name “NH film” by Shin Nippon Oil Co., Ltd., and a disk-shaped liquid crystal sold under the trade name “WV film” by FUJIFILM Corporation. Is a film with a tilt orientation, a fully biaxially oriented film sold by Sumitomo Chemical Co., Ltd. under the name “VAC film”, and also sold by Sumitomo Chemical Co., Ltd. under the product name “new VAC film”. There are biaxially oriented films.

Furthermore, those obtained by attaching a protective film to these optical films can also be used as optical films. As the protective film, a transparent resin film is used, and as the transparent resin, for example, an acetyl cellulose resin typified by triacetyl cellulose or diacetyl cellulose, a methacrylic resin typified by polymethyl methacrylate, a polyester resin, or a polyolefin Resin, polycarbonate resin, polyether ether ketone resin, polysulfone resin and the like. The resin constituting the protective film may contain an ultraviolet absorber such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a triazine compound, a cyanoacrylate compound, or a nickel complex compound. As the protective film, an acetyl cellulose resin film such as a triacetyl cellulose film is preferably used.

Among the optical films described above, the linearly polarizing plate is used in a state where a protective film is attached to one or both sides of a polarizer constituting the polarizer, for example, a polarizer film made of a polyvinyl alcohol-based resin. There are many. The elliptically polarizing plate described above is a laminate of a linearly polarizing plate and a retardation film, and the polarizing plate may also be in a state where a protective film is attached to one or both sides of the polarizer film. Many. When the pressure-sensitive adhesive layer according to the present invention is formed on such an elliptically polarizing plate, the pressure-sensitive adhesive layer is usually formed on the retardation film side.

It is preferable that the optical film with a pressure-sensitive adhesive has a release film attached to the surface of the pressure-sensitive adhesive layer and protects the surface of the pressure-sensitive adhesive layer until use. The optical film with the pressure-sensitive adhesive provided with the release film in this manner is formed by, for example, applying the above-mentioned pressure-sensitive adhesive composition on the release film to form a pressure-sensitive adhesive layer, and further optically applying the obtained pressure-sensitive adhesive layer. By a method of laminating a film, a method of applying a pressure-sensitive adhesive composition on an optical film to form a pressure-sensitive adhesive layer, attaching a release film to the surface of the pressure-sensitive adhesive to protect it, and making an optical film with a pressure-sensitive adhesive Can be manufactured. The release film used here is, for example, a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyarylate, etc. It can be one that has undergone mold processing.

Although the thickness of the pressure-sensitive adhesive layer is not particularly limited, it is usually preferably 30 μm or less, more preferably 10 μm or more, and further preferably 10 to 20 μm. When the thickness of the pressure-sensitive adhesive layer is 30 μm or less, the adhesiveness under high temperature and high humidity is improved, and there is a tendency that the possibility of floating or peeling between the glass substrate and the pressure-sensitive adhesive layer is reduced. It is preferable because the reworkability tends to improve, and if the thickness is 10 μm or more, even if the dimension of the optical film bonded thereto changes, the adhesive layer follows the change in dimension and fluctuates. Therefore, it is preferable because there is no difference between the brightness of the peripheral edge of the liquid crystal cell and the brightness of the center, and white spots and color unevenness tend to be suppressed. Conventionally, in general, the thickness of the pressure-sensitive adhesive layer adhered to the liquid crystal cell glass has been 25 μm as standard, but in the present invention, even if the thickness is 20 μm or less, sufficient performance as the pressure-sensitive adhesive layer is exhibited. To do.

The optical film with the pressure-sensitive adhesive of the present invention is attached to a glass substrate to form an optical laminate, and when there is some inconvenience and the optical film is peeled from the glass substrate, the pressure-sensitive adhesive layer is accompanied by the optical film. Since the surface of the glass substrate that has been peeled off and is in contact with the pressure-sensitive adhesive layer hardly causes fogging or adhesive residue, it is easy to re-attach the optical film with the pressure-sensitive adhesive again to the glass substrate after peeling. That is, it is excellent in so-called reworkability.

[Optical laminate]
The optical film with pressure-sensitive adhesive of the present invention can be laminated on a glass substrate with the pressure-sensitive adhesive layer to form an optical laminate. In order to laminate an optical film with an adhesive on a glass substrate to form an optical laminate, for example, the release film is peeled off from the optical film with an adhesive obtained as described above, and the exposed adhesive layer is removed from the surface of the glass substrate. You just have to stick together. Here, as a glass substrate, the glass substrate of a liquid crystal cell, the glass for glare-proof, the glass for sunglasses etc. can be mentioned, for example. Among them, an optical film with an adhesive (upper polarizing plate) is laminated on the glass substrate on the front side (viewing side) of the liquid crystal cell, and another optical film with adhesive (lower polarizing plate) on the glass substrate on the back side of the liquid crystal cell. The optical laminated body formed by laminating is preferable because it can be used as a panel (liquid crystal panel) for a liquid crystal display device. Examples of the material for the glass substrate include soda lime glass, low alkali glass, and non-alkali glass.

Examples of some suitable layer configurations of the optical laminate according to the present invention are shown in cross-sectional schematic views in FIG. In the example shown in FIG. 1 (A), a polarizing plate 5 is configured by sticking a protective film 3 having a surface treatment layer 2 on one side of a linear polarizing film 1 on the surface opposite to the surface treatment layer 2. Has been. In this example, the polarizing plate 5 is also the optical film 10 referred to in the present invention. The pressure-sensitive adhesive layer 20 containing the ionic compound described above is provided on the surface of the linearly polarizing film 1 opposite to the protective film 3 to form an optical film 25 with a pressure-sensitive adhesive. And the surface on the opposite side to the polarizing plate 5 of the adhesive layer 20 is bonded to the liquid crystal cell 30 which is a glass substrate, and the optical laminated body 40 is comprised.

In the example shown in FIG. 1 (B), a first protective film 3 having a surface treatment layer 2 is attached to one side of a linear polarizing film 1 on the surface opposite to the surface treatment layer 2, and the linear polarizing film A polarizing plate 5 is configured by sticking a second protective film 4 to the other surface of 1. Also in this example, the polarizing plate 5 is simultaneously the optical film 10 referred to in the present invention. On the outer side of the second protective film 4 constituting the polarizing plate 5, the pressure-sensitive adhesive layer 20 containing the ionic compound described above is provided, and the optical film 25 with pressure-sensitive adhesive is formed. And the surface on the opposite side to the polarizing plate 5 of the adhesive layer 20 is bonded to the liquid crystal cell 30 which is a glass substrate, and the optical laminated body 40 is comprised.

In the example shown in FIG. 1C, a polarizing film 5 is configured by sticking a protective film 3 having a surface treatment layer 2 on one surface of a linearly polarizing film 1 on the surface opposite to the surface treatment layer 2. Has been. On the surface of the linearly polarizing film 1 opposite to the protective film 3, a retardation film 7 is stuck via an interlayer adhesive 8 to constitute an optical film 10. On the outside of the retardation film 7 constituting the optical film 10, the pressure-sensitive adhesive layer 20 containing the ionic compound described above is provided, and the optical film 25 with pressure-sensitive adhesive is formed. And the surface on the opposite side to the optical film 10 of the adhesive layer 20 is bonded to the liquid crystal cell 30 which is a glass substrate, and the optical laminated body 40 is comprised.

In the example shown in FIG. 1 (D), the first protective film 3 having the surface treatment layer 2 is attached to one surface of the linearly polarizing film 1 on the surface opposite to the surface treatment layer 2 to form a straight line. On the other surface of the polarizing film 1, a second protective film 4 is stuck to form a polarizing plate 5. On the outer side of the second protective film 4 constituting the polarizing plate 5, a retardation film 7 is stuck via an interlayer adhesive 8 to constitute an optical film 10. On the outside of the retardation film 7 constituting the optical film 10, the pressure-sensitive adhesive layer 20 containing the ionic compound described above is provided, and the optical film 25 with pressure-sensitive adhesive is formed. And the surface on the opposite side to the optical film 10 of the adhesive layer 20 is bonded to the liquid crystal cell 30 which is a glass substrate, and the optical laminated body 40 is comprised.

In these examples, the first protective film 3 and the second protective film 4 are generally composed of a triacetyl cellulose film, but are composed of the various transparent resin films described above. You can also. The surface treatment layer formed on the surface of the first protective film 3 can be a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, or the like. Of these, a plurality of layers may be provided.

When laminating the retardation film 7 on the polarizing plate 5 as in the example shown in FIGS. 1C and 1D, as a suitable example of the retardation film 7 as long as it is a medium-sized liquid crystal display device, A quarter wave plate can be mentioned. In this case, it is general that the absorption axis of the polarizing plate 5 and the slow axis of the retardation film 7 which is a quarter wavelength plate are arranged so as to intersect at about 45 degrees. Depending on the characteristics, the angle may be shifted from 45 degrees to some extent. On the other hand, in the case of a large liquid crystal display device such as a television, a retardation film having various retardation values in accordance with the characteristics of the liquid crystal cell 30 is used for the purpose of phase difference compensation and viewing angle compensation of the liquid crystal cell 30. . In this case, the polarizing plate 5 and the retardation film 7 are generally arranged so that the absorption axis and the slow axis of the retardation film 7 are substantially orthogonal or substantially parallel. When the retardation film 7 is composed of a quarter wavelength plate, a uniaxial or biaxial stretched film is preferably used. When the retardation film 7 is provided for the purpose of retardation compensation or viewing angle compensation of the liquid crystal cell 30, in addition to the uniaxial or biaxially stretched film, it is also oriented in the thickness direction in addition to the uniaxial or biaxially stretched film. What is called an optical compensation film, such as a film or a film obtained by coating and fixing a retardation-expressing substance such as liquid crystal on a support film, can also be used as the retardation film 7.

Similarly, when the polarizing plate 5 and the retardation film 7 are bonded via the interlayer adhesive 8 as in the example shown in FIGS. 1C and 1D, the interlayer adhesive 8 includes An antistatic agent such as the ionic compound described above can be blended and an antistatic agent can be used. However, since there is usually not much antistatic property desired in this part, It is customary to use a general acrylic adhesive that does not contain an inhibitor. Further, as in the large liquid crystal display device described above, the polarizing axis 5 and the slow axis of the retardation film 7 are arranged so that the slow axis is substantially orthogonal or substantially parallel. In applications where the plate 5 and the retardation film 7 can be roll-to-roll bonded and re-peelability between them is not required, the interlayer adhesive 8 shown in FIGS. 1 (C) and (D). Instead, it is also possible to use an adhesive that, once bonded, can be firmly bonded and cannot be peeled off. Examples of such an adhesive include an aqueous adhesive that is composed of an aqueous solution or an aqueous dispersion and exhibits adhesive strength by evaporating water as a solvent, and UV curing that is cured by UV irradiation and exhibits adhesive strength. Examples thereof include a mold adhesive.

1C and 1D in which the pressure-sensitive adhesive layer 20 containing an ionic compound is formed on the retardation film 7 itself can be circulated by itself and is referred to in the present invention. It can be an optical film with an adhesive. An optical film with a pressure-sensitive adhesive in which a pressure-sensitive adhesive layer containing an ionic compound is formed on a retardation film can be bonded to a liquid crystal cell as a glass substrate to form an optical laminate, and the phase difference film. A polarizing plate can be bonded to the side to make another optical film with an adhesive.

FIG. 1 shows an example in which the optical film 25 with an adhesive is arranged on the viewing side of the liquid crystal cell 30, but the optical film with an adhesive according to the present invention is the back side of the liquid crystal cell, that is, the back. It can also be placed on the light side. When the optical film with pressure-sensitive adhesive of the present invention is disposed on the back side of the liquid crystal cell, a protective film having no surface treatment layer is employed instead of the protective film 3 having the surface treatment layer 2 shown in FIG. Others can be configured similarly to (A) to (D) of FIG. In this case, various optical films known to be disposed on the back side of the liquid crystal cell, such as a brightness enhancement film, a light collecting film, and a diffusion film, may be provided outside the protective film constituting the polarizing plate. Is possible.

As described above, the optical layered body of the present invention can be suitably used for a liquid crystal display device. The liquid crystal display device formed from the optical laminate of the present invention includes, for example, a notebook type, a desktop type, a personal computer liquid crystal display including a PDA (Personal Digital Assistance), a television, an in-vehicle display, an electronic dictionary, and a digital camera. It can be used for digital video cameras, electronic desk calculators, watches, etc.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” representing the amount used or content are based on weight unless otherwise specified.

In the following examples, the nonvolatile content is a value measured by a method according to JIS K5407. Specifically, the adhesive solution was taken in a petri dish at an arbitrary weight, and the residual non-volatile content after drying for 2 hours at 115 ° C. in an explosion-proof oven was expressed as a percentage of the weight of the solution first measured. It is. The weight average molecular weight is measured in series on a GPC device with four “TSK gel XL” manufactured by Tosoh Corp. and one “GPC KF-802” manufactured by Shodex Corp. in series. Tetrahydrofuran was used as the eluent, and the sample concentration was 5 mg / mL, the sample introduction amount was 100 μL, the temperature was 40 ° C., and the flow rate was 1 mL / min.

First, an example in which an acrylic resin that is a main component of the pressure-sensitive adhesive composition and satisfies the provisions of the present invention and those that deviate from the provisions of the present invention will be shown.

[Polymerization Example 1]
In a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer, 81.8 parts of ethyl acetate, 88.6 parts of butyl acrylate as (A-1), 2-methoxy acrylate as (A-2) A mixed solution of 10 parts of ethyl, 1.0 part of 2-hydroxyethyl acrylate as (A-3), and 0.4 part of acrylic acid was charged, and the air in the apparatus was replaced with nitrogen gas so as not to contain oxygen. The internal temperature was raised to 55 ° C. Thereafter, a total amount of a solution prepared by dissolving 0.14 part of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added. One hour after the addition of the initiator, an internal temperature of 54 to 56 was added while continuously adding ethyl acetate into the reaction vessel at an addition rate of 17.3 parts / hr so that the concentration of the acrylic resin excluding the monomer was 35%. The mixture was kept at 12 ° C. for 12 hours, and finally ethyl acetate was added to adjust the concentration of the acrylic resin to 20%. The obtained acrylic resin had a polystyrene-equivalent weight average molecular weight Mw of 1,750,000 and Mw / Mn of 4.9 by GPC. This is designated as acrylic resin A. The structural unit derived from 2-hydroxyethyl acrylate which is a hydroxyl group-containing monomer in the acrylic resin A is 1%, and the structural unit derived from acrylic acid which is a carboxyl group-containing monomer is 0.4%. It is.

[Polymerization Example 2]
In the monomer composition, an ethyl acetate solution of acrylic resin was obtained in the same manner as in Polymerization Example 1 except that the amount of butyl acrylate was changed to 78.6 parts and the amount of 2-methoxyethyl acrylate was changed to 20 parts. It was. The resulting acrylic resin had a polystyrene-equivalent weight average molecular weight Mw of 1,660,000 and Mw / Mn of 4.4 by GPC. This is designated as acrylic resin B. The structural unit derived from 2-hydroxyethyl acrylate which is a hydroxyl group-containing monomer in the acrylic resin B is 1%, and the structural unit derived from acrylic acid which is a carboxyl group-containing monomer is 0.4%. It is.

[Polymerization Example 3]
In the monomer composition, an ethyl acetate solution of an acrylic resin was obtained in the same manner as in Polymerization Example 1 except that the amount of butyl acrylate was changed to 58.6 parts and the amount of 2-methoxyethyl acrylate was changed to 40 parts. It was. The obtained acrylic resin had a polystyrene-equivalent weight average molecular weight Mw of 1,580,000 and Mw / Mn of 4.8 by GPC. This is designated as acrylic resin C. The structural unit derived from 2-hydroxyethyl acrylate which is a hydroxyl group-containing monomer in the acrylic resin C is 1%, and the structural unit derived from acrylic acid which is a carboxyl group-containing monomer is 0.4%. It is.

[Polymerization Example 4]
Of the monomer composition, the same procedure as in Polymerization Example 1 was conducted, except that the amount of butyl acrylate was changed to 93.6 parts, the amount of 2-methoxyethyl acrylate was changed to 5 parts, and the incubation time was changed to 18 hours. An ethyl acetate solution of an acrylic resin was obtained. The obtained acrylic resin had a polystyrene-equivalent weight average molecular weight Mw of 1,680,000 and Mw / Mn of 5.4 by GPC. This is designated as acrylic resin D. The structural unit derived from 2-hydroxyethyl acrylate which is a hydroxyl group-containing monomer in the acrylic resin D is 1%, and the structural unit derived from acrylic acid which is a carboxyl group-containing monomer is 0.4%. It is.

[Polymerization Example 5]
An ethyl acetate solution of an acrylic resin was obtained in the same manner as in Polymerization Example 1 except that the amount of butyl acrylate in the monomer composition was 98.6 parts and 2-methoxyethyl acrylate was not used. The obtained acrylic resin had a polystyrene-equivalent weight average molecular weight Mw of 1,470,000 and Mw / Mn of 4.4 by GPC. This is designated as acrylic resin E. The structural unit derived from 2-hydroxyethyl acrylate, which is a hydroxyl group-containing monomer, in acrylic resin E is 1%, and the structural unit derived from acrylic acid, which is a carboxyl group-containing monomer, is 0.4%. It is.

Table 1 shows a list of monomer compositions, weight average molecular weights, and Mw / Mn of polymerization examples 1 to 5. In the table, BA means butyl acrylate, MEA means 2-methoxyethyl acrylate, HEA means 2-hydroxyethyl acrylate, and AA means acrylic acid.

Next, Examples and Comparative Examples in which an adhesive composition was prepared using the acrylic resin produced above and applied to an optical film are shown. In the following examples, the following ionic compounds 1 to 3 were used as ionic compounds. The following ionic compounds 1 and 2 are solid at room temperature of 25 ° C., and ionic compound 3 is liquid at room temperature of 25 ° C.

Ionic compound 1 (solid): N-octyl-4-methylpyridinium hexafluorophosphate (having the structure of the following formula, melting point: 44 ° C.)

Ionic compound 2 (solid): tributylmethylammonium bis (trifluoromethanesulfonyl) imide (having the structure of the following formula, melting point: 28 ° C.)

Ionic compound 3 (liquid): N-hexyl-4-methylpyridinium hexafluorophosphate (having the structure of the following formula, melting point: 18 ° C.)

In addition, the following were used as the crosslinking agent and the silane compound (both are trade names).

<Crosslinking agent>
Coronate L: Obtained from an ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), Nippon Polyurethane Co., Ltd.

<Silane compounds>
KBM-403: Glycidoxypropyltrimethoxysilane (liquid), obtained from Shin-Etsu Chemical Co., Ltd.

[Examples 1-4 and Comparative Examples 1-2]
(A) Production of pressure-sensitive adhesive composition For each 100 parts of the solid content of acrylic resins A to E obtained in Polymerization Examples 1 to 5, 3 parts of each of the ionic compounds shown in Table 2 and the crosslinking agent “Coronate L” were added. 0.5 parts by solid content and 0.5 parts of the silane compound “KBM-403” were mixed, and ethyl acetate was further added so that the solid content concentration was 13% to obtain a pressure-sensitive adhesive composition. In the column of the ionic compounds in Table 2, the numbers of the ionic compounds 1 to 3 described above and whether they are solid or liquid at room temperature are shown.

(B) Production of optical film with pressure-sensitive adhesive Each of the above pressure-sensitive adhesive compositions was subjected to mold release treatment of a polyethylene terephthalate film (trade name “PET 3811”, obtained from Lintec Co., Ltd., referred to as a separator) subjected to a mold release process. It applied to the surface so that the thickness after drying might be set to 20 micrometers using an applicator, and it dried at 90 degreeC for 1 minute, and obtained the sheet-like adhesive. Next, on one side of a polarizing plate having a three-layer structure in which both sides of a polyvinyl alcohol polarizer to which iodine is adsorbed and oriented are sandwiched by protective films made of triacetyl cellulose, the surface opposite to the separator of the sheet-like adhesive obtained above ( The pressure-sensitive adhesive surface) was pasted with a laminator and then cured for 7 days under conditions of a temperature of 23 ° C. and a relative humidity of 65% to obtain a polarizing plate with a pressure-sensitive adhesive.

(C) Evaluation of antistatic property of optical film with adhesive When the separator of the obtained polarizing plate with adhesive is peeled off, the surface resistance value of the adhesive is determined by a surface resistivity measuring device ["Mitsubishi Chemical Co., Ltd." Hirest-up MCP-HT450 "(trade name)] to evaluate the antistatic property. In the IPS mode, a surface resistance value of 10 ¹⁰ Ω / □ order or less is required, and it is also required that the antistatic performance is maintained for a long time. The antistatic property was evaluated immediately after the curing of the polarizing plate with an adhesive was completed. In addition, in order to see the change with time when stored for a long time, the cured polarizing plate with adhesive was stored in an oven at a temperature of 60 ° C. and a relative humidity of 70% for 6 days, and then the separator was peeled off in the same manner as above. Then, the surface resistance value of the adhesive was measured. Here, storing for 6 days at a temperature of 60 ° C. and a relative humidity of 70% has almost the same effect as storing for 6 months at room temperature. The results are shown in Table 2.

(D) Production and Evaluation of Optical Laminate After separating the separator from the pressure-sensitive adhesive polarizing plate produced in (b) above, the pressure-sensitive adhesive surface was placed on a glass substrate for liquid crystal cells [“1737” (trade name, manufactured by Corning) )] Was pasted on one side to produce an optical laminate. When this optical laminate was subjected to a heat resistance test stored for 300 hours under dry conditions at a temperature of 80 ° C. (indicated as “heat resistance” in Table 2), the moisture resistance was stored for 300 hours at a temperature of 60 ° C. and a relative humidity of 90%. When a thermal test was performed (indicated as “moisture-resistant heat” in Table 2), the process of lowering the temperature from −70 ° C. to 70 ° C. and then raising the temperature to 70 ° C. was defined as one cycle (1 hour). For each case where a heat shock resistance test was repeated for 100 cycles (indicated as “HS resistance” in Table 2), the optical laminate after the test was visually observed. The results were classified according to the following criteria and summarized in Table 2.

<Evaluation criteria for durability against heat, moist heat and heat shock (referred to as "heat resistance", "moisture heat resistance" and "HS resistance" in Table 2, respectively)>
1: No change in appearance such as floating, peeling or foaming is observed.
2: Appearance changes such as floating, peeling and foaming are hardly observed.
3: Appearance changes such as floating, peeling and foaming are slightly noticeable.
4: Appearance changes such as floating, peeling and foaming are remarkably recognized.

(E) Reworkability evaluation of optical film with adhesive The reworkability was evaluated as follows. First, the polarizing plate with the adhesive obtained in (b) was cut into a test piece having a size of 25 mm × 150 mm. Next, the test piece was attached to the glass substrate for liquid crystal cell on the adhesive side using a sticking device ["Lami Packer" (trade name) manufactured by Fuji Plastics Co., Ltd.], 50 ° C., 5 kg / cm ² ( 490.3 kPa) for 20 minutes. Next, it was heat-treated at 70 ° C. for 2 hours, and subsequently stored in an oven at 50 ° C. for 48 hours, and then the polarizing plate was removed from this sticking test piece in an atmosphere of 23 ° C. and 50% relative humidity by 300 mm / It peeled in the direction of 180 degrees at the speed | rate of the minute, the state of the glass plate surface was observed, and it classified according to the following references | standards. The results are also shown in Table 2.

<Evaluation criteria for reworkability>
1: No fogging or the like is observed on the glass plate surface.
2: Most fogging etc. are not recognized on the glass plate surface.
3: Cloudiness etc. are recognized on the glass plate surface.
4: The remainder of an adhesive is recognized by the glass plate surface.

As can be seen from Tables 1 and 2, Examples 1 to 4 in which a predetermined amount of an ionic solid was blended with the acrylic resin defined in the present invention to constitute a pressure-sensitive adhesive composition were Comparative Examples 2 in which an ionic liquid was blended. Compared with, the antistatic property is almost the same in the initial stage of manufacture, and the antistatic property is hardly changed even after a long period of time. In addition, the heat resistance, moist heat resistance and heat shock resistance are almost satisfactory. was gotten.

In contrast, Comparative Example 1 in which the acrylic resin does not contain a structural unit derived from the ether type (meth) acrylic ester of the formula (II) has good results for heat resistance, moist heat resistance and heat shock resistance. Although given, the initial antistatic performance was low. Comparative Example 2 comprising an N-hexyl-4-methylpyridinium hexafluorophosphate (ionic compound 3) that is liquid at 25 ° C. to form a pressure-sensitive adhesive composition exhibits good antistatic properties at the initial stage of production. However, when stored for 6 days at a temperature of 60 ° C. and a relative humidity of 70%, which is a warming acceleration test, the surface resistance value after separation of the separator is 10 times or more than the initial value, and antistatic is prevented by long-term storage. There was a tendency for sex to decline.

It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The optical film with a pressure-sensitive adhesive of the present invention is imparted with high antistatic property, and the antistatic property is maintained for a long period of time, and is excellent in durability. This optical film with an adhesive is suitably used for a liquid crystal display device.

1 linear polarizing film, 2 surface treatment layer, 3rd protective film, 4th protective film, 5 polarizing plate, 7 retardation film, 8 interlayer adhesive, 10 optical film, 20 adhesive containing ionic compound Layer, 25 optical film with adhesive, 30 liquid crystal cell (glass substrate), 40 optical laminate.

Claims

An optical film with an adhesive in which an adhesive layer is formed on at least one surface of the optical film, the adhesive layer comprising:
(A) (A-1) The following formula (I)

(Wherein R 1 represents a hydrogen atom or a methyl group, and R 2 represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group)
(Meth) acrylic acid ester 55 to 94% by weight represented by
(A-2) The following formula (II)

(Wherein R 3 represents a hydrogen atom or a methyl group, R 4 represents an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 10)
(Meth) acrylic acid ester represented by 5 to 40% by weight, and
(A-3) 0.1 to 5% by weight of an unsaturated monomer having a polar functional group
100 parts by weight of an acrylic resin which is a copolymer obtained from a monomer mixture containing
(B) It is formed from a pressure-sensitive adhesive composition containing 0.3 to 12 parts by weight of an ionic compound which has an organic cation and is solid at room temperature, and (C) 0.1 to 5 parts by weight of a crosslinking agent. An optical film with an adhesive.
The optical film with an adhesive according to claim 1, wherein the (meth) acrylic acid ester represented by the formula (II) is 2-methoxyethyl acrylate.
2. The optical fiber with pressure-sensitive adhesive according to claim 1, wherein the polar functional group of the unsaturated monomer (A-3) having a polar functional group is selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring. the film
The optical film with pressure-sensitive adhesive according to claim 3, wherein the crosslinking agent (C) contains an isocyanate compound.
2. The optical film with an adhesive according to claim 1, wherein the adhesive composition further contains 0.03 to 1 part by weight of (D) a silane compound.
The optical film with an adhesive according to claim 1, wherein the optical film is selected from a polarizing plate and a retardation film.
2. The optical film with an adhesive according to claim 1, wherein a release film is adhered to the surface of the adhesive layer.
An optical laminate, wherein the optical film with an adhesive according to claim 1 is laminated on a glass substrate on the adhesive layer side.