JP6064637B2 - Pressure-sensitive adhesive sheet, optical film with pressure-sensitive adhesive, optical laminate, and method for producing pressure-sensitive adhesive sheet - Google Patents

Description

  The present invention relates to an adhesive sheet and an optical film with an adhesive using the same. Specifically, an adhesive sheet that is imparted with antistatic properties, has a silane compound, and has improved durability at high temperatures around 100 ° C. by controlling the content of silicon atoms derived from the silane compound. And an optical film with an adhesive using the same. The optical film targeted in the present invention includes, for example, a polarizing plate and a retardation film. The present invention also relates to an optical layered body to which the optical film with an adhesive is applied and is suitably used for liquid crystal display. The present invention further relates to a method for producing the above-mentioned pressure-sensitive adhesive sheet.

  The polarizing plate is mounted on a liquid crystal display device and widely used. The polarizing plate is distributed in a state in which protective films made of a transparent resin are laminated on both surfaces of the polarizing film, and a release film is attached to the surface of at least one protective film via an adhesive layer. Moreover, a retardation film is laminated on a polarizing plate having protective films bonded on both sides of the polarizing film to form an elliptical polarizing plate, and the adhesive layer / release film is attached in this order to the retardation film side. Alternatively, a protective film is bonded to one side of the polarizing film, and a retardation film is directly bonded to the other side to form an elliptical polarizing plate, with the adhesive layer / release film in this order on the retardation film side. Sometimes stuck. Furthermore, an adhesive layer / release film may be stuck in this order on the surface of the retardation film. In this specification, these polarizing plates, elliptical polarizing plates, retardation films, and the like are collectively referred to as optical films. Prior to bonding to the liquid crystal cell, the release film is peeled off from these optical films 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 the countermeasures, in Japanese Patent No. 3012860 (Patent Document 1), in a polarizing plate in which a protective film is laminated on the surface of a polarizing film and an adhesive layer is provided on the surface of the protective film, It has been proposed to use a mixture containing an ionic conductive composition comprising an electrolyte salt and an organopolysiloxane and an acrylic copolymer. Although the pressure-sensitive adhesive containing such an ion conductive composition exhibits antistatic properties, its performance is not necessarily sufficient, and it cannot be said that adhesion durability is sufficient.

  Therefore, Japanese Patent 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. JP-A-2004-114665 (Patent Document 3) includes a salt composed of a quaternary ammonium cation having a total carbon number of 4 to 20 and a fluorine atom-containing anion in an adhesive, etc. It is described to give. 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. Further, JP-A-2009-79205 (Patent Document 5) describes a polarizing plate coated with an adhesive by adding a specific ionic compound that becomes solid at room temperature (25 ° C.) to the adhesive. It is described that an optical film with a pressure-sensitive adhesive having excellent antistatic properties and durability can be obtained even if left for a long time without causing a change with time.

  On the other hand, the optical film with an adhesive as described above is bonded to a liquid crystal cell on the adhesive layer side to constitute 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 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. It may cause this. For this reason, development of the adhesive which does not produce such a malfunction and is excellent in durability is also calculated | required.

  An example of a document disclosing a pressure-sensitive adhesive having improved durability under high temperature or high temperature and high humidity is disclosed in Japanese Patent No. 3022993 (Patent Document 6), which includes an acrylic resin pressure-sensitive adhesive containing a silane compound having an epoxy group. It is described that the layer is provided on the surface of the polarizing plate. Japanese Patent No. 3487940 (Patent Document 7) describes an adhesive composition in which a curing agent and a specific silicate oligomer are blended in an acrylic resin, and the adhesive composition is used as an optical film such as a polarizing plate. It is also described to apply to. However, in the silicate oligomer, the silicate oligomer whose functional group site is deactivated with time may bleed out to the surface.

  Moreover, since the high temperature conditions to which the liquid crystal display device to which the optical film with an adhesive is applied are different depending on the use of the liquid crystal display device, it is required to have excellent durability even in a harsh environment. For example, a liquid crystal display device having a pressure-sensitive adhesive layer containing an ionic compound as described above as an antistatic agent or a pressure-sensitive adhesive layer containing a specific silane compound is a general temperature range in which a television or a monitor is used. In the test in the test, it shows sufficient durability, but in the test in a harsh environment such as in-vehicle use, the adhesive layer and the liquid crystal cell glass may float or peel off, especially When the moisture permeability of the optical film to which the pressure-sensitive adhesive layer is bonded is low, this tendency is remarkable.

  In addition, when the liquid crystal display device is exposed to high temperature conditions, the distribution of residual stress acting on the optical film becomes non-uniform and the stress concentrates on the outer periphery of the optical film. Since a phenomenon called “missing” may occur or color unevenness may occur, suppression of such white skipping or color unevenness is also required. Furthermore, if there is a problem when the optical film with adhesive is bonded to the liquid crystal cell, the optical film must be peeled off once and then a new film is attached again. A so-called rework property is also required in which the agent layer is peeled off along with the optical film, no adhesive remains on the cell glass, and no fogging occurs.

Japanese Patent No. 3012860 (= Japanese Patent Laid-Open No. 6-313807) Japanese translation of PCT publication No. 2004-536940 (= WO 2003/011958) JP 2004-114665 A JP 2006-307238 A JP 2009-79205 A Japanese Patent No. 3022993 (= JP-A-4-223403) Japanese Patent No. 3487940 (= Japanese Patent Laid-Open No. 8-199130)

  The problem of the present invention is that the antistatic property is imparted and the pressure-sensitive adhesive sheet is excellent in durability, and does not peel off even in a severe environment test assuming an in-vehicle application or the like when bonded to glass. And it is providing the optical film with an adhesive which provided this on the surface of the optical film. Another object of the present invention is to provide an optical laminate by bonding the optical film with an adhesive to a glass substrate having a liquid crystal cell as a representative example. Still another object of the present invention is to provide a method for producing the above-mentioned pressure-sensitive adhesive sheet.

  As a result of diligent research to solve such problems, the present inventors have made a monomer mixture containing (meth) acrylic acid ester as a main component and an unsaturated monomer having a polar functional group. It is formed from a pressure-sensitive adhesive composition in which a specific silane compound is further blended with an acrylic resin, which is a copolymer obtained from the above, to give antistatic properties by blending predetermined amounts of a crosslinking agent and an ionic compound, respectively. In the pressure-sensitive adhesive sheet, the amount of the silane compound remaining in the pressure-sensitive adhesive sheet, in particular, the weight ratio of silicon atoms due to the silane compound to the pressure-sensitive adhesive sheet is durable in severe high temperature conditions of around 100 ° C. The inventors have found that it has a great influence and have reached the present invention.

  That is, the pressure-sensitive adhesive sheet of the present invention comprises (meth) acrylic acid ester (A-1) 95 to 99.9% by weight and an unsaturated monomer (A-2) 0 having a polar functional group, which will be described in detail below. 100 parts by weight of an acrylic resin (A) which is a copolymer obtained from a monomer mixture containing 0.1 to 5% by weight, 0.01 to 5 parts by weight of a crosslinking agent (B), an organic cation, and a melting point It is formed from a pressure-sensitive adhesive composition containing 0.2 to 8 parts by weight of an ionic compound (C) at 25 ° C. or higher and 50 ° C. or lower, and a silane compound (D) having a boiling point of 350 ° C. or lower. The weight ratio of silicon atoms derived from the silane compound (D) to the agent sheet is 160 mg / kg or more.

The above (meth) acrylic acid ester (A-1) is represented by the following formula (I), wherein R ₁ represents a hydrogen atom or a methyl group; R ₂ represents an alkyl group or an aralkyl group having 14 or less carbon atoms. It represents a hydrogen atom constituting these groups may be substituted with a group _{-O- (C 2 H 4 O)} n -R 3, where n is an integer of 0 or 1 to 4 , R ₃ represents an alkyl group or aryl group having 12 or less carbon atoms.

  In this pressure-sensitive adhesive sheet, the unsaturated monomer (A-2) having a polar functional group serving as a constituent unit of the acrylic resin (A) has a free carboxyl group, a hydroxyl group, an amino group, or an epoxy ring as the polar functional group. And one or more of these compounds can be used. Moreover, in these adhesive sheets, it is preferable that a crosslinking agent (B) contains an isocyanate type compound.

  Since the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive sheet of the present invention generally exists in a state dissolved in a solvent, the pressure-sensitive adhesive composition (solution) is applied onto a suitable substrate, and the solvent is added. By removing by drying, an adhesive sheet is obtained. As one of the preferable base materials, a release film subjected to a release treatment can be exemplified. Therefore, in a preferred embodiment, the pressure-sensitive adhesive sheet is formed on a release film that has been subjected to a release treatment.

The optical film with pressure-sensitive adhesive of the present invention is one in which any of the above-mentioned pressure-sensitive adhesive sheets is bonded to the optical film. The optical film can include a polarizing plate and / or a retardation film. In particular, the optical film includes a retardation film, and the retardation film is advantageous when the moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% is 300 g / (m ² · 24 hr) or less. A typical example of such a retardation film having a low moisture permeability is a film composed of a cycloolefin resin.

  Said optical film with an adhesive can be laminated | stacked on the glass substrate on the adhesive sheet side, and can be set as the optical laminated body for liquid crystal displays. So, according to this invention, the optical laminated body by which the optical film with an adhesive by which said adhesive sheet is bonded by the optical film is laminated | stacked on the glass substrate by the adhesive sheet side is also provided.

  Moreover, the manufacturing method of the adhesive sheet | seat which concerns on this invention is (meth) acrylic acid ester (A-1) shown by said Formula (I) 95-99.9 weight%, and the unsaturated simple substance which has a polar functional group. 100 parts by weight of an acrylic resin (A) which is a copolymer obtained from a monomer mixture containing 0.1 to 5% by weight of a monomer (A-2), 0.01 to 5 parts by weight of a crosslinking agent (B), Contains 0.2 to 8 parts by weight of an ionic compound (C) having an organic cation and a melting point of 25 ° C. or higher and 50 ° C. or lower, a silane compound (D) having a boiling point of 350 ° C. or lower, and an organic solvent (E) A coating step for coating the pressure-sensitive adhesive composition on a substrate in a sheet form, and a drying step for drying the solvent from the coated sheet-like material to obtain a pressure-sensitive adhesive sheet are obtained. The weight ratio of silicon atoms derived from the silane compound (D) to the adhesive sheet is And carrying out so as not to fall below the 160 mg / kg.

  In this method, the pressure-sensitive adhesive composition used in the coating process is such that the weight ratio of silicon atoms constituting the silane compound (D) is 300 mg / kg or more and 1300 mg / kg or less based on the total solid weight. The silane compound (D) is preferably blended.

  The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive composition forming the same, in which an ionic compound (C) is blended in addition to the acrylic resin (A), the crosslinking agent (B) and the silane compound (D). By adopting, antistatic properties are imparted. In addition, this pressure-sensitive adhesive sheet is obtained by setting the weight ratio of silicon atoms derived from the silane compound (D) to the pressure-sensitive adhesive sheet to a predetermined value, and bonding it to an optical film to form an optical film with a pressure-sensitive adhesive. When the pressure-sensitive adhesive sheet side is attached to a glass substrate, it is excellent in durability under a harsh environment of around 100 ° C. assuming in-vehicle use.

  The optical film with the pressure-sensitive adhesive obtained by bonding the pressure-sensitive adhesive sheet of the present invention to an optical film, for example, is laminated on a glass substrate of a liquid crystal cell to give an optical laminate for liquid crystal display. This optical laminate absorbs and relieves stress caused by dimensional changes of the optical film and glass substrate under high heat conditions, so that local stress concentration is reduced and the pressure-sensitive adhesive layer floats on the glass substrate. And peeling are suppressed. In addition, 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.

  Hereinafter, the present invention will be described in detail. The pressure-sensitive adhesive sheet of the present invention is formed from a pressure-sensitive adhesive composition containing an acrylic resin (A), a crosslinking agent (B), an ionic compound (C) and a silane compound (D). This pressure-sensitive adhesive sheet can be bonded to an optical film to form an optical film with a pressure-sensitive adhesive. First, the component of the adhesive composition which forms an adhesive sheet is demonstrated.

[Acrylic resin (A)]
In the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive sheet of the present invention, the acrylic resin (A) serving as the resin component is mainly composed of the (meth) acrylic acid ester (A-1) represented by the formula (I). Furthermore, it is a copolymer obtained from a monomer mixture containing an unsaturated monomer (A-2) 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 this specification, the (meth) acrylic acid ester (A-1) represented by the formula (I) is referred to as “monomer (A-1)” and an unsaturated monomer (A-) having a polar functional group. 2) may be referred to as “monomer (A-2)”, respectively.

In the above formula (I), which is the main structural unit of the acrylic resin (A), R ₁ represents a hydrogen atom or a methyl group; R ₂ represents an alkyl group or an aralkyl group having 14 or less carbon atoms. May be substituted with a group —O— (C ₂ H ₄ O) _n —R ₃ , wherein n represents 0 or an integer of 1 to 4, and R ₃ has 12 carbon atoms. The following alkyl groups or aryl groups are represented.

Among the monomers (A-1), as R ₂ in the formula (I) is an unsubstituted alkyl group, specifically, methyl acrylate, ethyl acrylate, propyl acrylate, n-acrylate Linear alkyl acrylates such as 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, and lauryl methacrylate; and isobutyl methacrylate, 2-methacrylic acid 2- Such as ethylhexyl and isooctyl methacrylate Branched alkyl methacrylate are exemplified.

  Among these, it is preferable to use n-butyl acrylate as the monomer (A-1). Specifically, among all monomers constituting the acrylic resin (A), n-butyl acrylate is used. It is preferable that the amount is 50% by weight or more and satisfies the above-mentioned regulations regarding the monomer (A-1).

Further, among the monomers (A-1), specific examples of R ₂ in the formula (I) being an aralkyl group include benzyl acrylate and benzyl methacrylate.

Next, in the monomer (A-1), the hydrogen atom of the alkyl group or aralkyl group constituting R ₂ in the formula (I) is substituted with the group —O— (C ₂ H ₄ O) _n —R ₃ . I will explain what is being done. In this group —O— (C ₂ H ₄ O) _n —R ₃ , n is 0 or an integer of 1 to 4 as defined above, but 0, 1 or 2 is particularly preferable. R _{3 is} also an alkyl group or aryl group having 12 or less carbon atoms, as defined above, and may be linear or branched as long as the alkyl group has 3 or more carbon atoms. Examples of the aryl group constituting R ₃ include phenyl and naphthyl, as well as nuclear alkyl-substituted phenyl and biphenylyl (or phenylphenyl) including tolyl, xylyl, ethylphenyl and the like. R ₃ is particularly preferably these aryl groups.

Among the monomers (A-1), R ₂ in the formula (I) is an alkyl group, and the hydrogen atom is substituted with a group —O— (C ₂ H ₄ O) _n —R _3. Specifically, 2-methoxyethyl acrylate, ethoxymethyl acrylate, 2-phenoxyethyl acrylate, 2- (2-phenoxyethoxy) ethyl acrylate, and 2- (o-phenylphenoxy) ethyl acrylate Such as alkoxyalkyl-, aryloxyalkyl- or aryloxyethoxyalkyl-esters of acrylic acid; 2-methoxyethyl methacrylate, ethoxymethyl methacrylate, 2-phenoxyethyl methacrylate, 2- (2-phenoxyethoxy) methacrylate Alcohols of methacrylic acid such as ethyl and 2- (o-phenylphenoxy) ethyl methacrylate Shiarukiru -, aryloxyalkyl - or aryloxy ethoxyalkyl - such esters are exemplified.

These monomers (A-1) can be used alone or in combination with a plurality of different monomers. As described above, the monomer (A-1) is particularly preferably composed mainly of n-butyl acrylate, but in addition, other (meth) acrylic acid esters corresponding to the formula (I) Copolymerization is also effective. As a suitable composition of the monomer (A-1), among all the monomers constituting the acrylic resin (A), n-butyl acrylate is 50% by weight or more. In the formula (I), R ₂ is a hydrogen atom of the group —O— (C ₂ H ₄ O) _n —R ₃ (where n and R ₃ are as defined above). And (meth) acrylic acid ester which is an alkyl group substituted with 3) to 15% by weight.

  The unsaturated monomer (A-2) having a polar functional group is preferably a (meth) acrylic acid compound having a polar functional group. Examples of polar functional groups include free carboxyl groups, hydroxyl groups, amino groups, and heterocyclic groups including epoxy rings.

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

  Among these, it is preferable to use the unsaturated monomer which has a hydroxyl group as one of the monomers which have the polar functional group which comprises an acrylic resin (A). In addition to the unsaturated 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.

  In the acrylic resin (A), the structural unit derived from the (meth) acrylic acid ester represented by the formula (I), that is, the monomer (A-1), based on the total amount of the solid content. Content is 95-99.9 weight%, Preferably it is 98-99.6 weight%. Moreover, in said acrylic resin (A), content of the structural unit derived from the unsaturated monomer (A-2) which has a polar functional group on the basis of the quantity of the whole solid content is 0.1. -5% by weight, preferably 0.4-2% by weight.

  The acrylic resin (A) used in the present invention is derived from the (meth) acrylic acid ester (A-1) of the formula (I) described above and the unsaturated monomer (A-2) having a polar functional group. Although the structural unit is essential, a structural unit derived from a monomer other than these may be included. Examples of these include (meth) acrylic acid ester having an alicyclic structure in the molecule, styrene monomer, vinyl monomer, monomer having a plurality of (meth) acryloyl groups in the molecule, ( And (meth) acrylamide derivatives.

  The (meth) acrylic acid ester having an alicyclic structure in the molecule will be described. 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-acrylate Examples include butyl cyclohexyl, α-ethoxy acrylate cyclohexyl, cyclohexyl phenyl acrylate, and the like. Specific examples of the methacrylic acid ester having an alicyclic structure include isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, cyclododecyl methacrylate, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, tert-methacrylic acid tert- Examples include butyl cyclohexyl and cyclohexyl phenyl methacrylate.

  Next, examples of styrenic monomers include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octyl. Examples include alkyl styrene such as styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and 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 such as vinyl esters; vinyl halides such as vinyl chloride and vinyl bromide; Vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene, and chloroprene; and acrylonitrile, methacrylonitrile, etc. .

  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-nonane. In the molecule, such as diol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and 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.

  Examples of (meth) acrylamide derivatives include N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 3-hydroxypropyl (meth) acrylamide, 4-hydroxybutyl (meth) acrylamide, and 5-hydroxypentyl. (Meth) acrylamide, 6-hydroxyhexyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, N- (1,1-dimethyl) (Lu-3oxobutyl) (meth) acrylamide, N- [2- (2-oxo-1-imidazolidinyl) ethyl] (meth) acrylamide, 2-acryloylamino-2-methyl-1-propanesulfonic acid, and the like. it can.

  Monomers other than the above-mentioned monomers (A-1) and (A-2) can be used alone or in combination of two or more. In the acrylic resin (A) used for the pressure-sensitive adhesive, when the monomers other than the monomers (A-1) and (A-2) are copolymerized, the amount is based on the amount of the whole monomer. Usually, the proportion is preferably 0 to 4.9% by weight, more preferably 0 to 3% by weight.

  The resin component constituting the pressure-sensitive adhesive composition has the above-described (meth) acrylic acid ester represented by the formula (I), that is, a structural unit derived from the monomer (A-1) as a main component, and polar functionality. Two or more kinds of acrylic resins (A) containing a structural unit derived from an unsaturated monomer having a group, that is, the monomer (A-2) may be used. Furthermore, you may mix an acrylic resin different from it into the acrylic resin (A) which has a structural unit derived from a monomer (A-1) and a monomer (A-2) in a predetermined ratio. Examples of the different acrylic resin mixed in this case include an acrylic resin having a structural unit derived from the (meth) acrylic acid ester of the formula (I) and having no polar functional group. The acrylic resin (A) having a predetermined proportion of structural units derived from the monomers (A-1) and (A-2) is 60% by weight or more, further 80% by weight or more, based on the whole acrylic resin. Is preferred.

  The acrylic resin (A) obtained by copolymerization of the monomer mixture containing the monomers (A-1) and (A-2) is a weight average molecular weight in terms of standard polystyrene by gel permeation chromatography (GPC). Mw is preferably in the range of 1 million to 2 million. When the weight average molecular weight in terms of standard polystyrene is 1 million 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. Further, when the weight average molecular weight is 2 million or less, even when the pressure-sensitive adhesive layer is bonded to the optical film, even if the dimension of the optical film changes, the pressure-sensitive adhesive layer follows the dimensional change 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. The molecular weight distribution represented by the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn is preferably in the range of about 2 to 10 in general.

  Moreover, it is preferable that the glass transition temperature of the said acrylic resin (A) exists in the range of -10-60 degreeC for adhesive expression. The glass transition temperature of the resin can be measured by a differential scanning calorimeter.

  The acrylic resin constituting the pressure-sensitive adhesive composition may have only a relatively high molecular weight as described above, or a relatively low molecular weight acrylic resin mixed with a relatively high molecular weight acrylic resin (A). It may be a thing. As an example of the latter, when an acrylic resin different from the acrylic resin (A) is mixed, the different acrylic resin to be mixed is derived from the (meth) acrylic acid ester represented by the formula (I). The form which has a structural unit as a main component and has a weight average molecular weight Mw in the range of 50,000-300,000 can be mentioned.

  A mixture of the acrylic resin (A) or a different acrylic resin was dissolved in ethyl acetate to adjust the solid content concentration to 20% by weight at 25 ° C. at 20 Pa · s or less, more preferably 0.1 to 0.1%. It preferably exhibits a viscosity of 7 Pa · s. When the viscosity is 20 Pa · s 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 tends to be reduced. It is preferable because the property tends to be improved. Viscosity can be measured with a Brookfield viscometer.

  The acrylic resin (A) constituting the pressure-sensitive adhesive composition 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 in the production of the acrylic resin.

  As a 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. A desired monomer and an organic solvent are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and about 40 to 90 ° C, preferably 50 to 80 ° C. A method of stirring for about 3 to 15 hours at about ° C. can be mentioned. Moreover, in order to control reaction, you may add a monomer and a thermal-polymerization initiator continuously or intermittently during superposition | polymerization, or may be added in the state melt | dissolved in the organic solvent. Here, 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.

  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 the thermal polymerization initiator 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) And azo compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper Oxide, diisopropylperoxydicarbonate, dipropylperoxydicarbonate, tert-butylperoxide Organic peroxides such as xineodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide An oxide etc. can be mentioned. A redox initiator using a peroxide and a reducing agent in combination can also be used as the polymerization initiator.

[Crosslinking agent (B)]
Next, the crosslinking agent (B) constituting the pressure-sensitive adhesive composition will be described. The crosslinking agent (B) is a compound that reacts with a particularly polar functional group in the acrylic resin (A) to crosslink the acrylic resin. Specific examples include isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, and the like. Among these, the isocyanate compound, the epoxy compound, and the aziridine compound have at least two functional groups that can react with the polar functional group in the acrylic resin (A) in the molecule.

  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 making isocyanate compounds into dimers and trimers can also serve as crosslinking agents. These isocyanate compounds can be used in combination of two or more.

  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. These epoxy compounds can be used in combination of two or more.

  An aziridine-based compound is a compound having at least two skeletons of a three-membered ring 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 Examples include -1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and the like.

  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.

  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, a trimer or the like, a mixture of these isocyanate compounds, or the like is preferably used. 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.

  A crosslinking agent (B) is mix | blended in the ratio of 0.1-5 weight part with respect to 100 weight part of acrylic resins (A). The amount of the crosslinking agent (B) 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.

[Ionic compound (C)]
Next, the ionic compound (C) constituting the pressure-sensitive adhesive composition will be described. The ionic compound (C) is added as an antistatic agent. In the present invention, an ionic compound (C) having an organic cation and having a melting point of 25 ° C. or higher and 50 ° C. or lower is adopted. If it is an ionic compound having an organic cation and a melting point of 50 ° C. or lower, it exhibits appropriate compatibility with the acrylic resin (A) as the main component of the pressure-sensitive adhesive composition. However, since they are not necessarily completely compatible, when the pressure-sensitive adhesive layer is formed, the durability may be lowered, for example, foaming may occur in the pressure-sensitive adhesive layer, or floating or peeling may occur. In the present invention, it is possible to suppress a decrease in durability due to the fact that the composition other than the ionic compound (C) is also provided, and in particular, the presence of the silane compound (D) described later.

  Further, by using an ionic compound having a melting point of 25 ° C. or higher, that is, an ionic compound that is solid at room temperature, as disclosed in the above-mentioned Patent Document 5 (Japanese Patent Laid-Open No. 2009-79205), the antistatic performance is improved. Changes over time can be suppressed, in other words, antistatic performance can be maintained for a long time. From the viewpoint of long-term stability of the antistatic performance, it is more preferable that the ionic compound (C) has a melting point of 30 ° C. or higher, and further 35 ° C. or higher.

  Examples of the cation component constituting the ionic compound (C) include an imidazolium cation, a pyridinium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation. Among these, a pyridinium cation and an imidazolium cation are preferable from the viewpoint that when used in the pressure-sensitive adhesive layer of an optical film, it is difficult to be charged when a release film provided thereon is peeled off.

  On the other hand, in the ionic compound (C), the anion component serving as the counter ion of the cation component may be an inorganic anion or an organic anion, and examples thereof include the following. be able to.

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 ⁻ ],
Fluorosulfonate anion [FSO ₃ ⁻ ],
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 (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N ⁻ ],
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, in particular, an anion component containing a fluorine atom is preferably used because it provides an ionic compound having excellent antistatic performance, and in particular, a hexafluorophosphate anion, a bis (fluorosulfonyl) imide anion and a bis (trifluoromethanesulfonyl). An imide anion is preferred.

  Specific examples of the ionic compound 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.

・ Pyridinium salt:
N-hexylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-methyl-4-hexylpyridinium hexafluorophosphate,
N-butyl-4-methylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-hexylpyridinium bis (fluorosulfonyl) imide,
N-octylpyridinium bis (fluorosulfonyl) imide,
N-methyl-4-hexylpyridinium bis (fluorosulfonyl) imide,
N-butyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-octyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octylpyridinium bis (trifluoromethanesulfonyl) imide,
N-methyl-4-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-butyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-hexylpyridinium p-toluenesulfonate,
N-octylpyridinium p-toluenesulfonate,
N-methyl-4-hexylpyridinium p-toluenesulfonate,
N-butyl-4-methylpyridinium p-toluenesulfonate,
N-octyl-4-methylpyridinium p-toluenesulfonate and the like.

・ Imidazolium salt:
1-ethyl-3-methylimidazolium hexafluorophosphate,
1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide,
1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide,
1-ethyl-3-methylimidazolium p-toluenesulfonate,
1-butyl-3-methylimidazolium methanesulfonate and the like.

・ Pyrrolidinium salt:
N-butyl-N-methylpyrrolidinium hexafluorophosphate,
N-butyl-N-methylpyrrolidinium bis (fluorosulfonyl) imide,
N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide,
N-butyl-N-methylpyrrolidinium p-toluenesulfonate and the like.

・ Ammonium salt:
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium bis (fluorosulfonyl) imide,
Tetrahexylammonium bis (fluorosulfonyl) imide,
Trioctylmethylammonium bis (fluorosulfonyl) imide,
(2-hydroxyethyl) trimethylammonium bis (fluorosulfonyl) imide,
Tetrabutylammonium bis (trifluoromethanesulfonyl) imide,
Tetrahexylammonium bis (trifluoromethanesulfonyl) imide,
Trioctylmethylammonium bis (trifluoromethanesulfonyl) imide,
(2-hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide,
Tetrabutylammonium p-toluenesulfonate,
Tetrahexylammonium p-toluenesulfonate,
Trioctylmethylammonium p-toluenesulfonate,
(2-hydroxyethyl) trimethylammonium p-toluenesulfonate,
(2-hydroxyethyl) trimethylammonium dimethylphosphinate and the like.

  These ionic compounds can be used alone or in combination of two or more.

  As described above, the ionic compound (C) is effective in imparting antistatic properties to the pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition containing the acrylic resin (A) and maintaining various physical properties as a pressure-sensitive adhesive. is there. The molecular weight of the ionic compound (C) is not particularly limited, but for example, the molecular weight is preferably 700 or less, and more preferably 500 or less.

  An ionic compound (C) is mix | blended in the ratio of 0.2-8 weight part with respect to 100 weight part of above-described acrylic resin (A). When the blending ratio is 0.2 parts by weight or more, the antistatic performance is improved, and when the blending ratio is 8 parts by weight or less, the durability is easily maintained. The blending ratio of the ionic compound (C) to 100 parts by weight of the acrylic resin (A) is preferably 0.5 parts by weight or more and 5 parts by weight or less.

[Silane Compound (D)]
Next, the silane compound (D) which is another component which comprises an adhesive composition is demonstrated. A silane compound (D) is mix | blended in order to improve the adhesiveness of an adhesive sheet and a glass substrate. You may make the acrylic resin before mix | blending a crosslinking agent contain a silane compound.

  When a silicate oligomer as described in Japanese Patent No. 3487940 (Patent Document 7) is used as the silane compound, the silicate oligomer whose functional group site has been deactivated over time bleeds out to the surface, causing adhesion. The power may be reduced and durability may be deteriorated. Therefore, in the present invention, a silane compound (D) having a boiling point of 350 ° C. or lower is used. Such a silane compound having a low boiling point is basically a monomer, specifically a compound having one silicon atom in one molecule, and examples thereof include those represented by the following formula (II). .

Here, X represents a reactive organic functional group itself or an organic group having a reactive functional group; R ₄ represents an alkyl group having 4 or less carbon atoms; R ₅ represents an alkoxy group (usually 4 or less carbon atoms). And y represents an integer of 0 to 2.

  In the above formula (II), the reactive functional group constituting X can be, for example, a vinyl group, amino group, epoxy group, halogen atom, mercapto group, (meth) acryloyl group, isocyanato group, and the like. Of these, the vinyl group can be directly bonded to the silicon atom as a reactive organic functional group, or can be bonded to the silicon atom via an organic linking group in the form of vinyl phenyl. . Other epoxy groups, amino groups, halogen atoms, mercapto groups, (meth) acryloyl groups and isocyanato groups are usually bonded to silicon atoms via organic linking groups.

  Examples of the silane compound (D) satisfying the above formula (II) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyl. Dimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3- Glycidoxypropyltriethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3 -Methacryloyleo Shi trimethoxysilane, 3-mercaptopropyl trimethoxysilane. Two or more silane compounds may be used.

  Since these silane compounds are often liquids, they can be directly dissolved in an organic solvent together with the other components, the acrylic resin (A), the crosslinking agent (B), and the ionic compound (C).

[Other components constituting the pressure-sensitive adhesive composition]
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive sheet described above further includes a crosslinking catalyst, a weather resistance stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler, and an acrylic resin (A). You may mix | blend resin etc. It is also useful to add a UV curable compound to the PSA composition and form a PSA sheet, or paste it onto an optical film, and then cure it by irradiating with UV rays to form a harder PSA layer. It is. Among them, if a crosslinking catalyst is blended with the crosslinking agent in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheet can be prepared by aging in a short time, and the optical film and the pressure-sensitive adhesive layer generated in the resulting optical film with the pressure-sensitive adhesive are obtained. Can be prevented from floating and peeling, and foaming in the pressure-sensitive adhesive layer, and 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.

[Adhesive sheet and method for producing the same]
Each component which comprises the adhesive composition demonstrated above is mixed in the state melt | dissolved in the organic solvent, is apply | coated on an appropriate base material, it is made to dry, and it is set as an adhesive sheet. That is, this pressure-sensitive adhesive sheet comprises 95 to 99.9% by weight of (meth) acrylic acid ester (A-1) represented by the formula (I) and an unsaturated monomer (A-2) having a polar functional group. 100 parts by weight of acrylic resin (A) which is a copolymer obtained from a monomer mixture containing 0.1 to 5% by weight, 0.01 to 5 parts by weight of a crosslinking agent (B), an organic cation, melting point The base material is a pressure-sensitive adhesive composition containing 0.2 to 8 parts by weight of an ionic compound (C) having a boiling point of 350 ° C. or lower and an organic solvent (E) having a temperature of 25 ° C. or higher and 50 ° C. or lower. It is manufactured by a method comprising a coating step of coating in the form of a sheet and a drying step of drying the solvent from the coated sheet to obtain an adhesive sheet. Examples of the organic solvent (E) constituting the pressure-sensitive adhesive composition 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; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone are usually used.

  The substrate used in the coating process is generally a plastic film, and a typical example thereof is a release film that has been subjected to a release treatment. That is, the adhesive sheet which concerns on this invention is formed on the peeling film in which the mold release process was performed by one form. The release film is, for example, a film on which a pressure-sensitive adhesive composition of a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarylate is applied, and a release treatment such as silicone treatment is performed. Can be.

  In the present invention, the silicon atoms derived from the silane compound (D) remaining in the pressure-sensitive adhesive sheet obtained through the above drying step are set to 160 mg / kg or more by weight ratio to the pressure-sensitive adhesive sheet. In other words, the drying step is performed so that the weight ratio of silicon atoms derived from the silane compound (D) to the obtained pressure-sensitive adhesive sheet does not fall below 160 mg / kg. When the weight ratio of silicon atoms in the pressure-sensitive adhesive sheet is less than 160 mg / kg, the pressure-sensitive adhesive sheet is applied to an optical film, and the pressure-sensitive adhesive surface opposite to the optical film is further applied to glass and exposed to high temperature. In such a case, there is a high possibility of peeling or bubbles between the optical film and the pressure-sensitive adhesive sheet and / or between the glass and the pressure-sensitive adhesive sheet. This tendency becomes prominent when the moisture permeability of the optical film to which the pressure-sensitive adhesive sheet is bonded, particularly the layer directly touching the pressure-sensitive adhesive sheet, is small.

  The “weight ratio of silicon atoms to the pressure-sensitive adhesive sheet” or “weight ratio of silicon atoms in the pressure-sensitive adhesive sheet” as used herein refers to the weight of the sampled pressure-sensitive adhesive sheet and the weight of silicon atoms detected therefrom. , [Weight of silicon atom (mg) / Weight of pressure-sensitive adhesive sheet (kg)]. The weight of silicon atoms in the pressure-sensitive adhesive sheet can be determined by, for example, ICP (inductively coupled plasma) emission spectroscopic analysis.

  The silane compound, also called a silane coupling agent, usually exists in a liquid at room temperature, as described above. And since its melting | fusing point is comparatively high, it is not thought that it volatilizes in the drying process in adhesive sheet manufacture, and as far as the present inventors know, it does not touch such a report or literature. However, as shown in the examples described later, it was confirmed that the amount of silicon atoms remaining in the pressure-sensitive adhesive sheet decreased as the drying time increased. Although the reason is not necessarily clear, when an organic solvent volatilizes in a drying process, it is thought that a silane compound volatilizes with the solvent.

  If the silane compound is not volatilized in the drying process, the pressure-sensitive adhesive composition used in the above-described coating process only needs to contain the silane compound (D) at the minimum, that is, the entire solid of the pressure-sensitive adhesive composition. The weight ratio of silicon atoms constituting the silane compound (D) may be 160 mg / kg or more based on the partial weight (weight excluding the organic solvent). However, in reality, as described above, the silane compound (D) is often partially volatilized in the drying step. Therefore, the silane compound (D) in the pressure-sensitive adhesive composition is preferably blended so that the weight ratio of the silicon atoms constituting it to the total solid content of the pressure-sensitive adhesive composition is larger than the above value. . On the other hand, if the amount of the silane compound (D) in the pressure-sensitive adhesive sheet is too large, there is a possibility of bleeding out, so the amount naturally has an upper limit. The compounding amount of the silane compound (D) in the pressure-sensitive adhesive composition is such that the weight ratio of silicon atoms constituting the silane compound (D) is 300 mg / kg or more and 1300 mg / kg based on the total solid content weight of the pressure-sensitive adhesive composition. It is preferable to be as follows. The upper limit of the weight ratio of silicon atoms derived from the silane compound (D) to the pressure-sensitive adhesive sheet after the pressure-sensitive adhesive sheet is up to about 700 mg / kg is sufficient.

  It is preferable to perform a drying process on the conditions which volatilization of a silane compound (D) does not occur as much as possible. Therefore, the temperature is preferably about 50 to 150 ° C., and more preferably 70 to 120 ° C. The time is preferably about 30 to 180 seconds, more preferably 50 to 180 seconds.

  In the present invention, in consideration of the volatilization of the silane compound in the drying step described above, the blending amount and the drying conditions are set, and a silane compound having a boiling point of 350 ° C. or lower is used. When a silane compound having a boiling point higher than 350 ° C. is used, it tends to bleed out as described above, although it is difficult to volatilize in the drying process, the adhesive strength of the adhesive sheet is greatly reduced, and durability is deteriorated. There is. In addition, in order to prevent this bleed out, if the amount of the silane compound having a high boiling point is reduced or the drying conditions are made gentler than the above range, the amount of silicon atoms remaining in the pressure-sensitive adhesive sheet is small, or the drying is insufficient. Therefore, sufficient performance may not be exhibited. Examples of such silane compounds having a high boiling point include silicate oligomers formed by reacting silane compound monomers.

  The thickness of the pressure-sensitive adhesive sheet is not particularly limited, but when applied to an optical film with a pressure-sensitive adhesive, and further to an optical laminate, it is preferably 30 μm or less, preferably 10 μm or more, and more preferably 17 to 28 μm. It is. When the thickness of the pressure-sensitive adhesive sheet is 30 μm or less, 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 sheet tends to be reduced. Moreover, it is preferable because reworkability tends to be improved. In addition, when the thickness is 10 μm or more, even if the size of the laminated optical film is changed, the pressure-sensitive adhesive sheet fluctuates following the change in size, so that the brightness and center of the peripheral edge of the liquid crystal cell This is preferable because there is no difference between the brightness of the part and white spots and color unevenness tend to be suppressed. Conventionally, the thickness of the pressure-sensitive adhesive sheet adhered to the liquid crystal cell glass is generally 25 μm, but in the present invention, even if the thickness is 20 μm or less, sufficient performance as a pressure-sensitive adhesive layer is exhibited. To do.

[Optical film with adhesive]
The optical film with an adhesive of the present invention is obtained by providing an optical film with an adhesive layer formed from the above-described adhesive sheet. In this way, in the optical film with the pressure-sensitive adhesive in the state where the pressure-sensitive adhesive layer is bonded to the optical film, or in the optical laminated body in which the pressure-sensitive adhesive layer is further laminated on the glass substrate, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive sheet is In the specification, it may be simply referred to as “adhesive layer”. The optical film used here has optical properties, 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 transmits linearly polarized light having a vibrating surface orthogonal to the polarizing plate, reflects linearly polarized light having a vibrating surface in a certain direction, and orthogonally intersects it. There are a polarization separating plate that transmits linearly polarized light having a vibration surface, 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 film that expresses the function of a polarizing plate, particularly a linear polarizing plate (sometimes referred to as a polarizer), dichroism such as iodine or a dichroic dye is applied to a uniaxially stretched polyvinyl alcohol resin film. Examples include dyes that are adsorbed and oriented.

  A retardation film is an optical film exhibiting optical anisotropy, for example, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polycycloolefin, polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride. It is obtained by stretching a polymer film made of ride / polymethyl methacrylate, liquid crystal polyester, acetyl cellulose, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, polypropylene, methacrylic resin, etc. to about 1.0 to 6 times. A stretched film etc. are mentioned. Among these, a polymer film obtained by uniaxially or biaxially stretching a polycarbonate film, a cycloolefin resin film, or a methacrylic resin 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.

  The cycloolefin resin is, for example, a thermoplastic resin having a structural unit derived from a cycloolefin represented by norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene) or a derivative thereof. In addition to the ring-opened polymer of the present invention and the hydrogenated product of the ring-opened copolymer using two or more kinds of cycloolefins, addition copolymerization of cycloolefin with a chain olefin or an aromatic compound having a vinyl group It may be a coalescence. In addition, a polar group may be introduced.

Commercially available thermoplastic cycloolefin resins are, for example, produced by TOPAS ADVANCED POLYMERS GmbH, Germany, and sold by "TOPAS" and JSR, which are sold by Polyplastics in Japan. “ARTON”, “ZEONEX” and “ZEONOR” sold by Nippon Zeon Co., Ltd., “Apel” sold by Mitsui Chemicals, etc. )

  In forming such a cycloolefin-based resin into a film, a known film forming method such as a solvent casting method or a melt extrusion method is appropriately used for film formation. A formed cycloolefin-based resin film and a cycloolefin-based resin film further stretched and provided with a phase difference are also commercially available. For example, “Arton Film” sold by JSR Co., “Zeonor Film” sold by Nippon Zeon Co., Ltd., “Essina Retardation Film” sold by Sekisui Chemical Co., Ltd. ( There are trade names), and these can be used preferably.

When an adhesive layer is formed on an optical film including a retardation film and is bonded to glass via the adhesive layer, if the moisture permeability of the retardation film is small, moisture is difficult to escape from the adhesive layer, especially In many cases, it was disadvantageous in durability under high temperature conditions. On the other hand, in the optical film with pressure-sensitive adhesive according to the present invention, when an optical film including a retardation film is used, the retardation film is JIS Z 0208 “moisture-proof packaging material moisture permeability test method (cup method)”. Even when the moisture permeability measured at a temperature of 40 ° C. and a relative humidity of 90% is as small as 300 g / (m ² · 24 hr) or less, excellent durability is exhibited.

Examples of the retardation film having a low moisture permeability include films made of the cycloolefin resins listed above. Similarly, a film made of a methacrylic resin is one of retardation films having a low moisture permeability. A retardation film made of these cycloolefin-based resins or a retardation film made of a methacrylic resin has a moisture permeability of approximately 300 g / (m ² · 24 hr) or less at a temperature of 40 ° C. and a relative humidity of 90%. Here, the methacrylic resin is a polymer having methyl methacrylate as a main constituent monomer, and may be a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and a small amount of other monomers copolymerizable therewith. it can.

  Moreover, the film which expressed optical anisotropy by application | coating and orientation of a liquid crystalline compound, and the film which expressed optical anisotropy by application | coating of an inorganic layered compound can also be used as retardation film. In such a retardation film, a so-called temperature-compensated retardation film and a rod-like liquid crystal sold under the trade name “NH film” from JX Nippon Mining & Energy Co., Ltd. are tilted. Film, a film with a disc-shaped liquid crystal marketed under the trade name “WV film” from FUJIFILM Corporation, and a complete biaxial film sold under the trade name “VAC film” from Sumitomo Chemical Co., Ltd. There are also oriented films, such as biaxially oriented films sold under the trade name “new VAC film” by Sumitomo Chemical Co., Ltd.

  Further, those obtained by attaching a protective film to these optical films can also be used as the optical film. 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, and a nickel complex salt compound. As the protective film, an acetyl cellulose resin film such as a triacetyl cellulose film is preferably used.

  The linear polarizing plate mentioned above etc. are mentioned as an example of what the protective film was affixed on the optical film. The linearly polarizing plate is often used in a state where a protective film is attached to one side or both sides of a polarizing film constituting the polarizing plate, for example, a polarizing film made of polyvinyl alcohol resin. In addition, the elliptically polarizing plate is obtained by laminating a retardation film on a linear polarizing plate, and the linear polarizing plate is often in a state where a protective film is attached to one side or both sides of the polarizing film. When bonding the adhesive sheet of this invention to such an elliptically polarizing plate, an adhesive sheet is normally bonded by the phase difference film side.

  Moreover, it is preferable that the optical film with an adhesive of this invention sticks a peeling film on the adhesive layer surface, and is temporarily protected by the time of use. In this way, the optical film with the adhesive provided with the release film is formed by, for example, applying the above-mentioned adhesive composition to the release-treated surface of the release film to form an adhesive layer, and forming the adhesive layer on the obtained adhesive layer. Further, a method of laminating a resin film, a method of forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive composition on an optical film, and protecting the adhesive film by attaching a release film to the surface of the pressure-sensitive adhesive, thereby forming an optical film with a pressure-sensitive adhesive It can be manufactured.

[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 laminate formed by laminating is preferable because it can be used as a liquid crystal display device. Examples of the material for the glass substrate include soda lime glass, low alkali glass, and non-alkali glass.

  After sticking the optical film with adhesive on the glass substrate to make an optical laminate in this way, if there is any problem, peel the optical film from the glass substrate and paste a new optical film with adhesive. A so-called rework work may be required. When the optical film with the pressure-sensitive adhesive of the present invention performs such a rework operation, the pressure-sensitive adhesive layer is peeled off along with the optical film, and the surface of the glass substrate that has been in contact with the pressure-sensitive adhesive layer has fogging or adhesive residue. Since hardly occurs, it is easy to re-adhere the optical film with the adhesive to the glass substrate after peeling. That is, it is excellent in so-called reworkability.

  The optical layered body of the present invention can be used as a liquid crystal panel of a liquid crystal display device. The liquid crystal panel 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, a digital camera, It can be used for digital video cameras, electronic desk calculators, watches, etc.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, parts and% indicating the amount used or content are based on weight unless otherwise specified.

In the following examples, the weight average molecular weight is 4 columns of “TSKgel XL” manufactured by Tosoh Corporation as a column in the GPC device, and “Shodex GPC KF sold by Showa Denko K.K.
-802 ”, 5 in total, connected in series, tetrahydrofuran as eluent, sample concentration 5 mg / mL, sample introduction amount 100 μL, temperature 40 ° C., flow rate 1 mL / min, standard It is the value measured by polystyrene conversion.

  Moreover, in the following examples, the weight ratio of silicon atoms in the pressure-sensitive adhesive sheet is determined by calculating the weight of silicon (Si) by ICP emission spectroscopic analysis after pretreatment of the pressure-sensitive adhesive sheet by an alkali melting-hydrochloric acid dissolution method. , And a value calculated from the weight of the pressure-sensitive adhesive sheet used for the measurement.

  First, the example of superposition | polymerization which manufactured the acrylic resin is 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, 98.6 parts of butyl acrylate, 1.0 part of 2-hydroxyethyl acrylate, and 0.4 parts of acrylic acid The internal temperature was increased to 55 ° C. while the air in the apparatus was replaced with nitrogen gas and oxygen-free. Thereafter, a total amount of a solution prepared by dissolving 0.14 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added. The temperature was maintained at this temperature for 1 hour after the addition of the initiator, and then ethyl acetate was continuously added into the reaction vessel at an addition rate of 17.3 parts / hr while maintaining the internal temperature at 54 to 56 ° C. When 35% became 35%, the addition of ethyl acetate was stopped, and the mixture was kept at this temperature until 12 hours had passed since the start of addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the acrylic resin to 20% to prepare an acrylic resin ethyl acetate solution. The obtained acrylic resin had a polystyrene equivalent weight average molecular weight Mw of 1,230,000 and Mw / Mn of 3.9 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]
The monomer composition was changed to 81.8 parts of ethyl acetate, 78.6 parts of butyl acrylate, 20 parts of methyl acrylate, 1.0 part of 2-hydroxyethyl acrylate, and 0.4 part of acrylic acid. In the same manner as in Polymerization Example 1, an acrylic resin was produced. The obtained acrylic resin had a polystyrene equivalent weight average molecular weight Mw of 1,648,000 and Mw / Mn of 4.1 by GPC. This is designated as acrylic resin B. In the acrylic resin B, the proportion of structural units derived from 2-hydroxyethyl acrylate, which is a hydroxyl group-containing monomer, is 1%, and the proportion of structural units derived from acrylic acid, which is a carboxyl group-containing monomer, is 0.4. %.

  Next, examples and comparative examples in which pressure-sensitive adhesives were prepared using the acrylic resins A and B produced above and applied to an optical film are shown. In the following examples, the following compounds were used as a crosslinking agent, a silane compound, and an ionic compound.

<Crosslinking agent>
Coronate L: Trimethylolpropane adduct of tolylene diisocyanate in ethyl acetate solution (solid content: 75%), obtained from Nippon Polyurethane Co., Ltd. In Table 1 below, it is abbreviated as “Cor L”.
Takenate D-160N: Trimethylolpropane adduct of hexamethylene diisocyanate in ethyl acetate (solid content 75%), obtained from Mitsui Chemicals. In Table 1 below, this is abbreviated as “D-160N”.

<Silane compound>
KBM-403: 3-glycidoxypropyltrimethoxysilane (liquid), obtained from Shin-Etsu Chemical Co., Ltd. Boiling point 290 ° C.
KBE-402: 3-glycidoxypropyldiethoxymethylsilane (liquid), obtained from Shin-Etsu Chemical Co., Ltd. Boiling point 259 ° C.
KBM-303: 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (liquid), obtained from Shin-Etsu Chemical Co., Ltd. Boiling point 310 ° C.

<Ionic compounds>
N-octyl-4-methylpyridinium hexafluorophosphate, a compound represented by the following formula (II) and having a melting point of 44 ° C.

[Examples 1 to 11 and Comparative Examples 1 to 7]
(A) Preparation of pressure-sensitive adhesive composition Using the ethyl acetate solution of acrylic resin A and the ethyl acetate solution of acrylic resin B produced in Polymerization Examples 1 and 2, the ionicity shown above for each solid content of 100 parts A pressure-sensitive adhesive composition was prepared by mixing 3 parts of the compound, the crosslinking agent and the silane compound in the proportions shown in Table 1, and further adding ethyl acetate so that the solid concentration was 13%.

(B) Production of pressure-sensitive adhesive sheet Each pressure-sensitive adhesive composition prepared in (a) above was subjected to a release treatment on a polyethylene terephthalate film [trade name “SP-PLR382050”, obtained from Lintec Corporation, separator Is applied to the release-treated surface of the mold using an applicator so that the thickness after drying is 20 μm, and then the drying time is changed as shown in Table 1 at a temperature of 100 ° C. to produce an adhesive sheet. did. The weight ratio of silicon atoms (Si) in the obtained pressure-sensitive adhesive sheet is summarized in the “Si weight ratio” column of Table 1. In the table, “ND” means that no silicon atom was detected from the adhesive sheet as a result of the measurement.

(C) Preparation of polarizing plate with pressure-sensitive adhesive A protective film having a thickness of 80 μm made of triacetyl cellulose is bonded to one side of a polarizing film made of polyvinyl alcohol on which iodine is adsorbed and oriented, and A polarizing plate having a three-layer structure in which a 70 μm-thick retardation film made of an olefin-based resin (water permeability at a temperature of 40 ° C. and a relative humidity of 90% is 42 g / (m ² · 24 hr)) was prepared. After laminating the pressure-sensitive adhesive surface (surface opposite to the separator) of the pressure-sensitive adhesive sheet prepared in (b) above on the retardation film surface made of cycloolefin-based resin of this polarizing plate, the temperature was 23 ° C. A polarizing plate with an adhesive was prepared by curing for 7 days under the condition of a relative humidity of 65%.

(D) Production and Evaluation of Optical Laminate After separating the separator from the pressure-sensitive adhesive polarizing plate produced in (c) above, the pressure-sensitive adhesive surface was placed on a glass substrate for liquid crystal cells [trade name “EAGLE XG”, Corning Inc. To obtain an optical layered body. The optical laminate was subjected to a high heat resistance test that was stored for 300 hours under dry conditions at a temperature of 100 ° C., and the optical laminate after the test was visually observed to classify the appearance changes according to the following criteria. The results are summarized in the column of “High heat resistance” in Table 1.

<Evaluation criteria for high heat resistance test>
A: No change in appearance such as floating, peeling or foaming is observed.
○: Almost no change in appearance such as floating, peeling or foaming.
Δ: Appearance changes such as floating, peeling and foaming are slightly noticeable.
X: Remarkable changes in appearance such as floating, peeling, foaming, etc.

(E) Reworkability evaluation of polarizing plate with adhesive The reworkability was evaluated by the following method. First, the polarizing plate with an adhesive produced in the above (c) was cut into a test piece having a size of 25 mm × 150 mm. Next, the separator is peeled off from the test piece, and the pressure-sensitive adhesive surface is attached to a glass substrate for a liquid crystal cell using a sticking apparatus (trade name “Lamipacker” manufactured by Fuji Plastics Co., Ltd.), temperature 50 ° C., pressure 5 kg / pressure. Autoclaving was performed at cm ² (490.3 kPa) for 20 minutes. Next, after heat-treating at 70 ° C. for 2 hours and subsequently storing in an oven at 50 ° C. for 48 hours, the polarizing plate is removed from the adhesion test piece in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. It peeled in the direction of 180 ° with the layer at a speed of 300 mm / min (direction parallel to the glass surface when the polarizing plate was peeled upside down), observed the state of the glass plate surface, and classified according to the following criteria: . The results are also shown in the “Rework” column of Table 1.

<Evaluation criteria for reworkability>
A: No fogging or the like is observed on the glass plate surface.
A: Almost no fogging or the like is observed on the glass plate surface.
(Triangle | delta): Cloudiness etc. are recognized by the glass plate surface.
X: The remainder of an adhesive is recognized by the glass plate surface.

  As shown in Table 1, even when the pressure-sensitive adhesive composition was blended with exactly the same composition, the weight ratio of the remaining silicon atoms changed depending on the drying time after coating to form a pressure-sensitive adhesive sheet, and at 100 ° C. The results when performing a high heat resistance test stored for 300 hours also vary greatly. For example, in Example 1, Example 4, Comparative Example 3, and Comparative Example 6, the compounding composition was 0.8 parts of the crosslinking agent “Takenate D-160N” and the silane compound “KBM-303” with respect to 100 parts of the acrylic resin A. "0.3 parts and ionic compound 3 parts were blended in exactly the same composition, and from this blending composition, the weight ratio of silicon atoms to the solid content of the pressure-sensitive adhesive composition was calculated to be 329 mg / kg. . On the other hand, in Example 1 where the drying time was 60 seconds, the measurement result of the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet was 334 mg / kg. Although it is considered that it remains in the 100% pressure-sensitive adhesive sheet, in Example 4 in which the drying time was tripled to 180 seconds, the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet was nearly half that at the time of blending. Further, in Comparative Example 3 in which the drying time was 300 seconds, the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet was 126 mg / kg, and in Comparative Example 6 in which the drying time was 600 seconds, the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet was 63 mg / kg, both of which are below the values specified in the present invention, and accordingly, the results of the high heat resistance test are also insufficient. From these facts, it can be seen that it is effective to increase the durability in a high heat environment so that the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet obtained after drying does not fall below 160 mg / kg. In order to prevent the weight ratio of silicon atoms to the pressure-sensitive adhesive sheet from falling below 160 mg / kg, in addition to shortening the drying time as in the above example, the drying temperature was set low to volatilize the silane compound. It is conceivable to set a large amount of the silane compound in the pressure-sensitive adhesive composition at the time of coating in consideration of suppressing the amount of silane compound that volatilizes in the drying process.

  The pressure-sensitive adhesive sheet of the present invention is imparted with antistatic properties, and is bonded to an optical film to form an optical film with a pressure-sensitive adhesive. When the pressure-sensitive adhesive sheet is bonded to glass via the pressure-sensitive adhesive sheet, etc. It is excellent in durability under harsh environments. This optical film with an adhesive is suitably used for a liquid crystal display device.

Claims (12)

(A) (A-1) The following formula (I)

(In the formula, R ₁ represents a hydrogen atom or a methyl group; R ₂ represents an alkyl group or an aralkyl group having 14 or less carbon atoms, and the hydrogen atom constituting these groups is a group —O— (C ₂ H ₄ O) may be substituted with _n- R ₃ , where n represents 0 or an integer of 1 to 4, and R ₃ represents an alkyl group or aryl group having 12 or less carbon atoms)
95 to 99.9% by weight of (meth) acrylic acid ester represented by formula (A-2) and 0.1 to 5% by weight of 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) 0.01 to 5 parts by weight of a crosslinking agent,
(C) Formed from a pressure-sensitive adhesive composition containing 0.2 to 8 parts by weight of an ionic compound having an organic cation and a melting point of 25 ° C. or higher and 50 ° C. or lower, and (D) a silane compound having a boiling point of 350 ° C. or lower. A pressure-sensitive adhesive sheet,
A pressure-sensitive adhesive sheet, wherein the weight ratio of silicon atoms derived from the silane compound (D) to the pressure-sensitive adhesive sheet is 270 mg / kg or more. The pressure-sensitive adhesive sheet according to claim 1, wherein the weight ratio is 545 mg / kg or more. The pressure-sensitive adhesive according to claim 1 or 2 , wherein the unsaturated monomer (A-2) having a polar functional group has a polar functional group selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring. Agent sheet. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the crosslinking agent (B) comprises an isocyanate compound. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive sheet is formed on a release film that has been subjected to a release treatment. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive sheet is bonded to an optical film. The optical film with an adhesive according to claim 6 , wherein the optical film is selected from a polarizing plate and a retardation film. Includes an optical film is a retardation film, retardation films, optical with a pressure-sensitive adhesive according to claim 7 moisture permeability at a temperature and 90% relative humidity 40 ° C. is 300g / (m 2 · ^24hr) or less the film. The optical film with an adhesive according to claim 8 , wherein the retardation film is composed of a cycloolefin-based resin. An optical laminated body, wherein the optical film with the pressure-sensitive adhesive according to any one of claims 6 to 9 is laminated on a glass substrate on the pressure-sensitive adhesive sheet side. (A) (A-1) The following formula (I)

(In the formula, R ₁ represents a hydrogen atom or a methyl group; R ₂ represents an alkyl group or an aralkyl group having 14 or less carbon atoms, and the hydrogen atom constituting these groups is a group —O— (C ₂ H ₄ O) may be substituted with _n- R ₃ , where n represents 0 or an integer of 1 to 4, and R ₃ represents an alkyl group or aryl group having 12 or less carbon atoms)
95 to 99.9% by weight of (meth) acrylic acid ester represented by formula (A-2) and 0.1 to 5% by weight of 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) 0.01 to 5 parts by weight of a crosslinking agent,
(C) 0.2-8 parts by weight of an ionic compound having an organic cation and a melting point of 25 ° C. or higher and 50 ° C. or lower,
(D) a silane compound having a boiling point of 350 ° C. or less, and (E) a coating step of coating the substrate with a pressure-sensitive adhesive composition containing an organic solvent, and
A method for producing a pressure-sensitive adhesive sheet comprising a drying step of drying a solvent from a coated sheet to obtain a pressure-sensitive adhesive sheet,
The said drying process is performed so that the weight ratio of the silicon atom derived from the silane compound (D) with respect to the adhesive sheet obtained may not be less than 270 mg / kg. The pressure-sensitive adhesive composition used in the coating process is based on the total solid weight so that the weight ratio of silicon atoms constituting the silane compound (D) is 300 mg / kg or more and 1300 mg / kg or less. The manufacturing method of Claim 11 with which D) is mix | blended.