JP6632821B2 - Adhesive, adhesive sheet and optical film with adhesive layer - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and an optical film with a pressure-sensitive adhesive layer, and more particularly, to a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and an optical film with a pressure-sensitive adhesive layer suitable for optical films such as polarizing plates and composite polarizing plates. Things.

  2. Description of the Related Art In recent years, as a display panel of various electronic devices, a touch panel serving both as a display device and an input unit has been widely used. Touch panel types are mainly resistive, capacitive, optical and ultrasonic, resistive are analog resistive and matrix resistive, and capacitive are surface resistive. Types and projection types.

  As a touch panel in a mobile electronic device such as a smartphone or a tablet terminal that has recently been receiving attention, a projection-type capacitive touch panel is often used. For example, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, a transparent conductive film ( It has been proposed that a protective plate such as ITO) and tempered glass is laminated.

  A liquid crystal cell is generally used as an optical component constituting the liquid crystal display device. The liquid crystal cell is generally arranged so that the orientation layers of the two transparent electrode substrates on which the orientation layers are formed are positioned inside with spacers at predetermined intervals, and the periphery thereof is sealed to seal the two transparent electrode substrates. A liquid crystal material is sandwiched between them. Usually, a polarizing plate or a composite polarizing plate having a retardation plate is bonded to the outside of two transparent electrode substrates in a liquid crystal cell via an adhesive.

  As an optical pressure-sensitive adhesive, for example, the one shown in Patent Document 1 is known. This pressure-sensitive adhesive contains, as a monomer unit, 0.2 to 20 parts by mass of a carboxyl group-containing monomer as a copolymer component with respect to 100 parts by mass of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms. (Meth) acrylic polymer, and 0.02 to 2 parts by mass of a peroxide and 0.005 to 5 parts by mass of an epoxy crosslinking agent as a crosslinking agent with respect to 100 parts by mass of the (meth) acrylic polymer. It contains.

  However, the conventional pressure-sensitive adhesive disclosed in Patent Document 1 or the like has insufficient durability, and may float or peel off under high-temperature conditions or wet-heat conditions. In addition, as mobile electronic devices have become thinner in recent years, optical films such as polarizing plates have also become thinner.However, thin polarizing plates have a high shrinkage ratio due to heat or the like, and conventional adhesives are not suitable for display panels. Warpage occurs. In particular, when a monomer having a high glass transition point (Tg) is copolymerized as a component of the (meth) acrylic polymer in order to improve the durability of the pressure-sensitive adhesive, a large shrinkage stress is generated under heat-resistant conditions. As a result, the warpage of the display panel increases. Further, a problem has been pointed out that light leakage (so-called thermal unevenness) occurs due to displacement of the optical axis of the optical film due to stress at the time of thermal contraction of the optical film.

  Meanwhile, an optical film such as a release sheet or a polarizing plate or a composite polarizing plate on which the pressure-sensitive adhesive is laminated is usually made of a plastic material. Therefore, the electrical insulation is high, and static electricity is easily generated when the release sheet is peeled off. If a polarizing plate or a composite polarizing plate is bonded to a liquid crystal cell in a state where the generated static electricity remains, the alignment of liquid crystal molecules may be disturbed. Cause problems.

  Then, in order to obtain effective antistatic performance, it has been proposed to add an antistatic agent to the pressure-sensitive adhesive composition (for example, Patent Documents 2 and 3).

JP 2009-242786 A JP 2007-316377 A JP 2009-155585 A

  However, when the above-mentioned antistatic agent is added to the pressure-sensitive adhesive composition, there is a problem that the durability of the obtained pressure-sensitive adhesive is lower than usual. Further, when the adhesive comes into contact with the transparent conductive film of the transparent electrode substrate, there is a problem that the transparent conductive film is corroded depending on the type of the antistatic agent to deteriorate the appearance. In particular, silver, copper, aluminum, and the like, which are expected as conductive materials to replace ITO, tend to be severely corroded.

  The present invention has been made in view of such a situation, does not corrode the transparent conductive film, exhibits good antistatic properties, is excellent in durability, hardly warps the display panel, and has uneven heat. An object of the present invention is to provide an adhesive, an adhesive sheet, and an optical film with an adhesive layer, which hardly occur.

  In order to achieve the above object, first, the present invention provides, as monomer units constituting a polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3). A (meth) acrylate copolymer (A) having a hydroxyl value of 5 to 20 mgKOH / g, an acid value of 5 mgKOH / g or less, a weight average molecular weight of 1.3 to 3,000,000, and an isocyanate An adhesive obtained from an adhesive composition containing a system crosslinking agent (B) and an antistatic agent (C), wherein the gel fraction of the adhesive is 62 to 90%, The pressure-sensitive adhesive is characterized in that the agent (C) is an ionic compound containing fluorosulfonylimide as an anion (Invention 1).

  According to the above invention (Invention 1), even when affixed to a transparent conductive film such as ITO, silver, copper, and aluminum, the transparent conductive film does not corrode, exhibits good antistatic properties, and has high durability. Excellent, the display panel is hardly warped, and heat unevenness is hardly generated.

  In the above invention (Invention 1), the alicyclic structure in the alicyclic structure-containing monomer (a1) is preferably a polycyclic alicyclic structure (Invention 2).

  In the above inventions (Inventions 1 and 2), the adhesive composition preferably further contains an epoxy group-containing silane coupling agent (D1) (Invention 3).

  In the above inventions (Inventions 1 to 3), it is preferable that the adhesive composition further contains a mercapto group-containing silane coupling agent (D2) (Invention 4).

  In the above inventions (Inventions 1 to 4), the isocyanate-based crosslinking agent (B) is preferably a compound having an aromatic ring (Invention 5).

  Secondly, the present invention provides a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive (Inventions 1 to 5) (Invention 6).

  Thirdly, the present invention provides an optical device with an adhesive layer, comprising: an optical film; and an adhesive layer comprising the adhesive (Inventions 1 to 5) laminated on at least one surface of the optical film. A film is provided (Invention 7).

  According to the pressure-sensitive adhesive, the pressure-sensitive adhesive sheet, and the optical film with a pressure-sensitive adhesive layer of the present invention, the transparent conductive film is corroded even when attached to a new transparent conductive film (for example, silver, copper, aluminum, or the like) instead of ITO. In addition, they exhibit good antistatic properties, are excellent in durability, and do not easily warp the display panel, and hardly cause heat unevenness.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the optical film with an adhesive layer which concerns on one Embodiment of this invention. It is sectional drawing of the optical film with an adhesive layer which concerns on other embodiment of this invention. It is sectional drawing which shows the example of a structure of a phase difference plate. It is a figure (color) which shows the evaluation standard of the heat resistance unevenness test (visual observation) in the optical film with an adhesive layer.

Hereinafter, embodiments of the present invention will be described.
(Adhesive)
The pressure-sensitive adhesive according to this embodiment contains, as monomer units constituting a polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3), and has a hydroxyl value of 5 (preferably 5.0) to 20 mg KOH / g, an acid value of 5 mg KOH / g or less, and a (meth) acrylate copolymer (A) having a weight average molecular weight of 1.3 to 3,000,000. An adhesive obtained from an adhesive composition containing an isocyanate-based cross-linking agent (B) and an antistatic agent (C) (hereinafter sometimes referred to as “adhesive composition P”), wherein a gel component An adhesive having a rate of 62 to 90%. The antistatic agent (C) is an ionic compound containing fluorosulfonylimide as an anion. In addition, in this specification, a (meth) acrylic ester means both an acrylic ester and a methacrylic ester. The same applies to other similar terms.

  The pressure-sensitive adhesive satisfying the above requirements is a new transparent conductive film that replaces ITO, such as silver, copper, and aluminum. When used for a display panel, it has excellent durability, and is prevented from floating or peeling under high temperature conditions, wet heat conditions or under heat shock. Further, a display panel using the above-mentioned pressure-sensitive adhesive is hardly warped even under a high temperature condition, and further, hardly generates heat unevenness.

  If the hydroxyl value of the (meth) acrylate copolymer (A) is less than 5 mgKOH / g, the crosslinking point is too small, the cohesive strength is reduced, and the resulting pressure-sensitive adhesive does not exhibit excellent durability. Further, when the hydroxyl value of the (meth) acrylate copolymer (A) exceeds 20 mgKOH / g, the number of crosslinking points is too large, the resulting pressure-sensitive adhesive is not flexible, and the stress relaxation property is reduced. In addition, the display panel may be warped or heat uneven under high temperature conditions.

  From the above viewpoint, the lower limit of the hydroxyl value of the (meth) acrylate copolymer (A) is preferably 5.0 mgKOH / g or more, more preferably 8 mgKOH / g or more, and particularly preferably 10 mgKOH / g. / G or more. The upper limit of the hydroxyl value of the (meth) acrylate copolymer (A) is preferably 18 mgKOH / g or less, particularly preferably 16 mgKOH / g or less.

  On the other hand, when the acid value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or less, the object to which the pressure-sensitive adhesive is to be adhered is one having a problem due to acid, for example, ITO, silver, copper, aluminum, etc. Even in the case of a transparent conductive film, such problems due to acid can be suppressed. That is, corrosion of the transparent conductive film or change in the resistance value of the transparent conductive film can be suppressed. The above-mentioned metal films of silver, copper, aluminum and the like usually do not have light transmittance. However, in this technical field, a metal film is also expected to be used after being thinned by patterning. In this case, even in the case of a metal film, light rays are transmitted through the gap between the fine wires. Therefore, in this specification, these metal films are also classified as transparent conductive films.

  From the above viewpoint, the upper limit of the acid value of the (meth) acrylate copolymer (A) is preferably 2 mgKOH / g or less, and particularly preferably 1 mgKOH / g or less. The lower limit of the acid value of the (meth) acrylic acid ester copolymer (A) is preferably as small as possible, and therefore it is particularly preferably 0 mgKOH / g.

  Here, the hydroxyl value and the acid value in the present specification are basically theoretical values derived from the mixing ratio of the (meth) acrylate copolymer (A), and when the theoretical values cannot be derived, The value is measured based on JIS K0070.

  When the weight average molecular weight of the (meth) acrylate copolymer (A) is less than 1.3 million, the durability of the pressure-sensitive adhesive according to the present embodiment is deteriorated. Further, when the weight average molecular weight of the (meth) acrylate copolymer (A) exceeds 3,000,000, the stress relaxation of the pressure-sensitive adhesive according to the present embodiment is reduced, and the display panel is warped under high temperature conditions. Or heat unevenness occurs.

  From the above viewpoint, the lower limit of the weight average molecular weight of the (meth) acrylate copolymer (A) is preferably 1.5 million or more, and particularly preferably 1.6 million or more. The upper limit of the weight average molecular weight of the (meth) acrylate copolymer (A) is preferably 2.5 million or less, and particularly preferably 1.9 million or less.

  Here, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

  If the gel fraction of the pressure-sensitive adhesive according to the present embodiment is less than 62%, the durability of the pressure-sensitive adhesive deteriorates. Further, when the gel fraction of the pressure-sensitive adhesive according to the present embodiment exceeds 90%, the stress relaxation property of the pressure-sensitive adhesive according to the present embodiment is reduced, and the display panel may be warped or may have uneven heat under high temperature conditions. Or occur.

  From the above viewpoint, the lower limit of the gel fraction of the pressure-sensitive adhesive according to the present embodiment is preferably 65% or more, and particularly preferably 73% or more. The upper limit of the gel fraction of the pressure-sensitive adhesive according to this embodiment is preferably 85% or less, and particularly preferably 78% or less. The method for measuring the gel fraction of the pressure-sensitive adhesive is as shown in Test Examples described later.

  The pressure-sensitive adhesive according to the present embodiment exhibits good antistatic properties by containing an antistatic agent (C) which is an ionic compound containing fluorosulfonylimide as an anion. Further, the antistatic agent (C) does not impair the durability of the adhesive and does not corrode the transparent conductive film. Therefore, the pressure-sensitive adhesive containing the antistatic agent (C) can achieve both the antistatic property and the durability, has excellent corrosion resistance to the transparent conductive film, and maintains the appearance of the transparent conductive film satisfactorily. can do.

(1) (meth) acrylate copolymer (A)
The (meth) acrylate copolymer (A) in the present embodiment includes, as monomer units constituting the polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (A3) is contained. By containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2) among these monomers, the resulting pressure-sensitive adhesive can have both an appropriate cohesive force and a stress relaxation property. At the same time, the adhesion to an optical film or a transparent conductive film is increased, so that when used for a display panel, excellent durability, warpage suppression and heat resistance unevenness can be exhibited.

  The (meth) acrylate copolymer (A) is a monomer unit constituting the polymer, wherein the alicyclic structure-containing monomer (a1), the aromatic ring-containing monomer (a2) and the hydroxyl group-containing monomer (a3) In addition, it is preferable to contain an alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group. Further, if desired, other monomers may be contained.

  The (meth) acrylic acid ester copolymer (A) has a preferable adhesive property by containing, as a monomer unit constituting the polymer, an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms. Can be expressed. Examples of the alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n- (meth) acrylate. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate and the like. Among them, from the viewpoint of further improving the adhesiveness, a (meth) acrylate having 1 to 8 carbon atoms in the alkyl group is preferable, and n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is particularly preferable. . These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester copolymer (A) contains 40 to 97.5% by mass of a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. Preferably, the content is 55 to 94% by mass, more preferably 65 to 83% by mass. When the (meth) acrylic acid alkyl ester is contained in an amount of 40% by mass or more, the (meth) acrylic acid ester copolymer (A) can be imparted with suitable adhesiveness. Further, when the content of the alkyl (meth) acrylate is 97.5% by mass or less, a desired amount of another monomer component can be introduced into the (meth) acrylate copolymer (A).

  The carbon ring of the alicyclic structure in the alicyclic structure-containing monomer (a1) may have a saturated structure or may have an unsaturated bond in part. The alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic or tricyclic structure. The alicyclic structure is a polycyclic alicyclic structure (from the viewpoint of appropriately setting the distance between the obtained (meth) acrylate copolymers (A) and imparting stress relaxation to the pressure-sensitive adhesive. (A polycyclic structure). Further, in consideration of the compatibility between the (meth) acrylate copolymer (A) and other components, the polycyclic structure is particularly preferably a bicyclic to tetracyclic structure. In addition, from the viewpoint of imparting stress relaxation properties as described above, the number of carbon atoms in the alicyclic structure (refers to the total number of carbon atoms in a portion forming a ring, and when a plurality of rings are independently present, , The total number of carbon atoms thereof) is usually preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, but is preferably 15 or less, particularly preferably 10 or less from the viewpoint of compatibility as described above.

  Examples of the alicyclic structure include a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isobornyl skeleton, and a cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, and the like). , A cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), a norbornene skeleton, a norbornadiene skeleton, a cubane skeleton, a basket skeleton, a hausan skeleton, a spiro skeleton, and the like. Those containing a dicyclopentadiene skeleton (carbon number of an alicyclic structure: 10), an adamantane skeleton (carbon number of an alicyclic structure: 10) or an isobornyl skeleton (carbon number of an alicyclic structure: 7) are preferable, and in particular, Contains isobornyl skeleton Preference is.

  As the alicyclic structure-containing monomer (a1), a (meth) acrylate monomer containing the above skeleton is preferable, and specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, Adamantyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and the like, among which more excellent durability, Dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate or isobornyl (meth) acrylate are preferred, and isobornyl (meth) acrylate is particularly preferred. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester copolymer (A) is an alicyclic monomer as a monomer unit constituting the polymer, from the viewpoint that the resulting pressure-sensitive adhesive exhibits excellent durability, warpage suppression and heat resistance unevenness. It is preferable to contain the structure-containing monomer (a1) in an amount of 1 to 20% by mass. Furthermore, in addition to the above-mentioned viewpoints, from the viewpoint that the obtained pressure-sensitive adhesive exhibits excellent reworkability, the alicyclic structure-containing monomer (a1) more preferably contains 2 to 15% by mass, and more preferably 3 to 9% by mass. % Is particularly preferred.

  As the aromatic ring-containing monomer (a2), a (meth) acrylate having an aromatic ring is preferable. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a fluorene ring and the like, and among them, a benzene ring is preferable.

  Examples of the aromatic ring-containing monomer (a2) include phenyl (meth) acrylate, 2-phenylethyl (meth) acrylate, benzyl (meth) acrylate, naphthyl (meth) acrylate, and phenoxyethyl (meth) acrylate Phenoxybutyl (meth) acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified cresol (meth) acrylate, ethylene oxide (EO) -modified nonylphenol (meth) acrylate, among others. From the viewpoint of improving cohesion, 2-phenylethyl (meth) acrylate is preferred. These may be used alone or in combination of two or more.

  The (meth) acrylate copolymer (A) preferably contains 1 to 30% by mass of an aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer, and particularly contains 3 to 25% by mass. And more preferably 12 to 22% by mass. When the content of the aromatic ring-containing monomer (a2) is in the above range, the resulting pressure-sensitive adhesive can exhibit excellent durability, warpage suppression, and unevenness in heat resistance.

  The (meth) acrylic ester copolymer (A) contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer. The hydroxyl group has high reactivity with the isocyanate group of the isocyanate-based crosslinking agent (B), and the (meth) acrylate copolymer (A) is crosslinked by the isocyanate-based crosslinking agent (B) by the reaction thereof. With this crosslinked structure, the resulting pressure-sensitive adhesive has excellent durability.

  Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. , Hydroxyalkyl (meth) acrylates such as 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, among others, the reactivity with the isocyanate-based crosslinking agent (B). To 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate is preferred, and 2-hydroxyethyl (meth) acrylate is particularly preferred. These may be used alone or in combination of two or more.

  The (meth) acrylate copolymer (A) preferably contains 0.5 to 10% by mass of a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, and particularly preferably 1 to 5% by mass. It is preferably contained, and more preferably 2 to 4% by mass. When the content of the hydroxyl group-containing monomer (a3) is within the above range, the hydroxyl value of the (meth) acrylate copolymer (A) tends to fall within the range described above, and excellent durability and warpage suppressing property are obtained. In addition, heat resistance unevenness can be effectively exhibited.

  The (meth) acrylate copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer in order to keep the acid value in the above-described range, and even if it does, , 0.5% by mass or less, and particularly preferably 0.1% by mass or less.

  The (meth) acrylic acid ester copolymer (A) may contain other monomers other than the above-mentioned monomers as the monomer units constituting the polymer. The other monomer includes a functional group reactive with the isocyanate-based cross-linking agent (B) so as not to hinder the reaction between the hydroxyl group of the hydroxyl-containing monomer (a3) and the isocyanate-based cross-linking agent (B). No monomers are preferred.

  Examples of such other monomers include non-crosslinkable acrylamides such as (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, acrylamide, and methacrylamide; Non-crosslinkable (meth) acrylates having a tertiary amino group, such as N, N-dimethylaminoethyl acrylate and N, N-dimethylaminopropyl (meth) acrylate, and vinyl acetate are exemplified. These may be used alone or in combination of two or more.

  The polymerization mode of the (meth) acrylate copolymer (A) may be a random copolymer or a block copolymer.

  Here, in the adhesive composition P, as the (meth) acrylate copolymer (A), one type may be used alone, or two or more types may be used in combination. In addition, the adhesive composition P further includes a (meth) acrylic acid ester polymer not containing the alicyclic structure-containing monomer (a1), the aromatic ring-containing monomer (a2) or the hydroxyl group-containing monomer (a3) as a constituent monomer unit. May be contained.

(2) Isocyanate-based crosslinking agent (B)
The isocyanate-based cross-linking agent (B) has an advantage of being excellent in reactivity with a hydroxyl group (derived from the hydroxyl group-containing monomer (a3)) of the (meth) acrylate copolymer (A).

  The isocyanate-based crosslinking agent (B) contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include, for example, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. And adducts which are reaction products with biuret, isocyanurate, and low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. And “denatured form”). Among these, from the viewpoint of the durability of the obtained pressure-sensitive adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified product thereof is preferable, and an organic group (for example, an alkylene chain is preferable in the aromatic ring; A polyisocyanate having an isocyanate group bonded via an alkylene chain of 1 to 4 is particularly preferred, or a modified product thereof. Specifically, xylylene diisocyanate or a modified product thereof is more preferable, and trimethylolpropane-modified xylylene diisocyanate is most preferable. The isocyanate-based crosslinking agent (B) may be used alone or in combination of two or more.

  The content of the isocyanate-based crosslinking agent (B) in the adhesive composition P is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylate copolymer (A). And particularly preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 0.4 parts by mass. When the content of the isocyanate-based cross-linking agent (B) is within the above range, the gel fraction of the pressure-sensitive adhesive easily falls within the above-mentioned range, and a pressure-sensitive adhesive excellent in durability, warpage suppression and heat resistance unevenness can be obtained. It will be easier.

(3) Antistatic agent (C)
The adhesive composition P contains an antistatic agent (C). An optical film such as a release sheet laminated on an adhesive layer or a polarizing plate or a composite polarizing plate is usually made of a plastic material, so that it has high electrical insulation properties and generates static electricity when the release sheet is peeled off. Easy to do. If a polarizing plate or a composite polarizing plate is bonded to a liquid crystal cell in a state where the generated static electricity remains, the alignment of liquid crystal molecules may be disturbed. This causes problems such as inhalation. Then, when the pressure-sensitive adhesive composition P contains the antistatic agent (C), the obtained pressure-sensitive adhesive (pressure-sensitive adhesive layer) exhibits antistatic properties, and the above-described problem can be solved.

  The antistatic agent (C) in the present embodiment is an ionic compound containing fluorosulfonylimide as an anion. The antistatic agent (C) does not impair the durability of the pressure-sensitive adhesive formed from the (meth) acrylate copolymer (A) and the isocyanate-based crosslinking agent (B), and corrodes the transparent conductive film. Do not let. Therefore, the pressure-sensitive adhesive containing the antistatic agent (C) can achieve both the antistatic property and the durability, has excellent corrosion resistance to the transparent conductive film, and maintains the appearance of the transparent conductive film satisfactorily. can do. Here, the ionic compound in this specification refers to a compound in which a cation and an anion are bound mainly by electrostatic attraction.

  The cation contained in the ionic compound is not particularly limited, but is preferably a nitrogen-containing heterocyclic cation. That is, the antistatic agent (C) is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and fluorosulfonylimide (anion). Such an ionic compound is particularly excellent in terms of antistatic properties, durability, and corrosion resistance to the transparent conductive film.

  As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, a triazole ring, an indole ring and the like are preferable, and a pyridine ring is particularly preferable. Further, the fluorosulfonylimide is particularly preferably bis (fluorosulfonyl) imide.

  The ionic compound is preferably a solid at room temperature. When it is solid at room temperature, it is easy to exhibit stable antistatic properties even when exposed to durable conditions.

  Specific examples of the antistatic agent (C) include N-decylpyridinium bis (fluorosulfonyl) imide, 1-ethylpyridinium bis (fluorosulfonyl) imide, 1-butylpyridinium bis (fluorosulfonyl) imide, 1-hexyl Pyridinium bis (fluorosulfonyl) imide, 1-butyl-3-methylpyridinium bis (fluorosulfonyl) imide, 1-butyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-hexyl-3-methylpyridinium bis (fluoro Sulfonyl) imide, 1-butyl-3,4-dimethylpyridinium bis (fluorosulfonyl) imide and the like. Among them, N-decylpyridinium bis (fluorosulfonyl) imide is preferable from the viewpoint of corrosion resistance to the transparent conductive film. One of the above antistatic agents (C) may be used alone, or two or more thereof may be used in combination.

  The content of the antistatic agent (C) in the adhesive composition according to the present embodiment is 0.1 to 15 parts by mass with respect to 100 parts by mass of the (meth) acrylate copolymer (A). It is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass. When the content of the antistatic agent (C) is within the above range, the antistatic property can be effectively exhibited, and a decrease in physical properties such as optical characteristics and durability can be prevented.

(4) Silane coupling agent (D)
The pressure-sensitive adhesive composition P preferably contains a silane coupling agent (D) in addition to the above components, and from the viewpoint of imparting excellent durability to the obtained pressure-sensitive adhesive, particularly, an epoxy group-containing silane coupling agent ( It preferably contains D1) and / or a mercapto group-containing silane coupling agent (D2), and further contains both an epoxy group-containing silane coupling agent (D1) and a mercapto group-containing silane coupling agent (D2). Is preferred.

  The epoxy group-containing silane coupling agent (D1) is an organosilicon compound having at least one epoxy group (organic group including an epoxy group) and at least one alkoxysilyl group in a molecule, and includes an adhesive component Those having good compatibility and having light transmissivity, for example, substantially transparent are preferable.

  Specific examples of the epoxy group-containing silane coupling agent (D1) include 3-glycidoxypropyl trialkoxysilane such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane; 3-glycidoxypropylalkyl dialkoxysilane such as sidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, methyltri (glycidyl) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane And 2- (3,4-epoxycyclohexyl) ethyl trialkoxysilane such as 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane. Above all, from the viewpoint of further improving the durability, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl) ) Ethyltrimethoxysilane is preferred, especially 3-glycidoxypropyltrimethoxysilane. These may be used alone or in combination of two or more.

  The mercapto group-containing silane coupling agent (D2) is an organosilicon compound having at least one mercapto group (organic group containing a mercapto group) and at least one alkoxysilyl group in the molecule, Those having good compatibility and having light transmissivity, for example, substantially transparent are preferable.

  Specific examples of the mercapto group-containing silane coupling agent (D2) include mercapto group-containing low molecular weight silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Agents: Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyl An oligomer type silane coupling agent containing a mercapto group, such as a cocondensate with an alkyl group-containing silane compound such as trimethoxysilane, and the like. Among them, from the viewpoint of achieving both durability and reworkability, a mercapto group-containing oligomer-type silane coupling agent is preferable, and a co-condensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable. Co-condensates of mercaptopropyltrimethoxysilane and methyltriethoxysilane are preferred. These may be used alone or in combination of two or more.

  As the silane coupling agent (D), in addition to the epoxy group-containing silane coupling agent (D1) and the mercapto group-containing silane coupling agent (D2), if necessary, for example, an acryloyl-based silane coupling agent; A hydroxyl group-based silane coupling agent, a carboxyl group-based silane coupling agent, an amino group-based silane coupling agent, an amide group-based silane coupling agent, an isocyanate group-based silane coupling agent, or the like may be used in combination.

  The total content of the silane coupling agent (D) in the adhesive composition P may be 0.01 to 5 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A). Preferably, it is particularly preferably 0.1 to 2 parts by mass, more preferably 0.2 to 1 part by mass.

  The content of the epoxy group-containing silane coupling agent (D1) in the adhesive composition P is 0.005 to 2.5 with respect to 100 parts by mass of the (meth) acrylate copolymer (A). It is preferable that it is a mass part, It is especially preferable that it is 0.05-1 mass part, and it is more preferable that it is 0.1-0.5 mass part. On the other hand, the content of the mercapto group-containing silane coupling agent (D2) in the adhesive composition P is 0.005 to 2.5 with respect to 100 parts by mass of the (meth) acrylate copolymer (A). It is preferable that it is a mass part, It is especially preferable that it is 0.05-1 mass part, and it is more preferable that it is 0.1-0.5 mass part.

(5) Various additives In the pressure-sensitive adhesive composition P, if desired, various additives commonly used for acrylic pressure-sensitive adhesives, for example, dispersants (for example, alkylene glycol dialkyl ether), tackifiers, antioxidants Agents, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index adjusters and the like can be added. The pressure-sensitive adhesive composition P represents a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or in a reacted state, and is a component that is removed in a drying step or the like, for example, a polymerization described later. The solvent and the diluting solvent are not included in the adhesive composition P.

(Production method of adhesive composition)
The pressure-sensitive adhesive composition P produces a (meth) acrylic ester copolymer (A), and the obtained (meth) acrylic ester copolymer (A), an isocyanate-based crosslinking agent (B), It can be produced by mixing the inhibitor (C) and, if desired, a silane coupling agent (D), an additive and the like.

  The (meth) acrylate copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a usual radical polymerization method. The polymerization of the (meth) acrylate copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator, if desired. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like, and two or more kinds may be used in combination.

  Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), , 2'-Azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate) 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) Propane] and the like.

  Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxy dicarbonate, di-n-propyl peroxy dicarbonate, and di (2-ethoxyethyl) peroxy. Examples include dicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy bivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

  In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

  When the (meth) acrylate copolymer (A) is obtained, the solution of the (meth) acrylate copolymer (A) is mixed with an isocyanate-based crosslinking agent (B), an antistatic agent (C), , A silane coupling agent (D), an additive, a diluting solvent and the like are added, and the mixture is sufficiently mixed to obtain an adhesive composition P (coating solution) diluted with the solvent.

  Examples of the diluting solvent for diluting the adhesive composition P into a coating solution include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, methylene chloride, ethylene chloride and the like. Halogenated hydrocarbons, alcohols such as methanol, ethanol, propanol, butanol and 1-methoxy-2-propanol, acetone, methyl ethyl ketone, ketones such as 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and ethyl A cellosolve-based solvent such as cellosolve is used.

  The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they can be coated, and can be appropriately selected according to the situation. For example, the adhesive composition P is diluted so that the concentration of the adhesive composition P becomes 10 to 40% by mass. In addition, when obtaining a coating solution, addition of a diluting solvent or the like is not a necessary condition, and the diluting solvent may not be added as long as the viscosity is such that the adhesive composition P can be coated. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylate copolymer (A) as a diluting solvent as it is.

  The pressure-sensitive adhesive according to the present embodiment is obtained from the pressure-sensitive adhesive composition P described above, and specifically, is obtained by crosslinking the pressure-sensitive adhesive composition P. Crosslinking of the adhesive composition P can be performed by a heat treatment. In addition, this heat treatment can also serve as a drying treatment when the solvent for diluting the adhesive composition P is volatilized.

  When performing a heat treatment, the heating temperature is preferably from 50 to 150 ° C, particularly preferably from 70 to 120 ° C. Further, the heating time is preferably from 30 seconds to 10 minutes, particularly preferably from 50 seconds to 2 minutes. After the heat treatment, a curing period of about 1 to 2 weeks may be provided at room temperature (for example, 23 ° C., 50% RH) as necessary. When this curing period is required, after the curing period elapses, and when the curing period is not required, an adhesive layer having predetermined physical properties is formed after the completion of the heat treatment.

  By the heat treatment (and curing), the (meth) acrylate copolymer (A) is cross-linked by the isocyanate-based cross-linking agent (B) to form a three-dimensional network structure.

(Adhesive sheet)
The pressure-sensitive adhesive sheet according to the present embodiment has a pressure-sensitive adhesive layer made of the above-described pressure-sensitive adhesive. A release sheet may be laminated on one side or both sides of the pressure-sensitive adhesive layer. Further, a release sheet may be laminated on one surface of the pressure-sensitive adhesive layer, and a desired base material may be laminated on the other surface. In addition, when the base material is an optical film, in this specification, the pressure-sensitive adhesive sheet corresponds to an optical film with a pressure-sensitive adhesive layer described later.

  The thickness of the pressure-sensitive adhesive layer is appropriately determined depending on the purpose of use of the pressure-sensitive adhesive sheet, and is usually in the range of 5 to 100 μm, preferably 10 to 60 μm, for example, when used as a pressure-sensitive adhesive layer of an optical film. Is preferably from 10 to 50 μm, particularly preferably from 15 to 30 μm.

  As the release sheet, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, Polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Is used. These crosslinked films are also used. Further, these laminated films may be used.

  It is preferable that at least one surface of the release sheet (particularly, the release surface in contact with the pressure-sensitive adhesive layer) has been subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. In addition, the release surface of the release sheet in this specification refers to a surface having releasability in the release sheet, and includes both the surface subjected to the release treatment and the surface exhibiting the releasability even without performing the release treatment. .

  When laminating release sheets on both sides of the pressure-sensitive adhesive layer, it is preferable that one release sheet is a heavy release type release sheet having a large release force and the other release sheet is a light release type release sheet having a small release force.

  The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

  The substrate is not particularly limited, and any substrate used as a substrate sheet of a normal pressure-sensitive adhesive sheet can be used. For example, in addition to a desired optical member (optical film), a woven or nonwoven fabric using fibers such as rayon, acrylic, and polyester; synthetic paper; paper such as high-quality paper, glassine paper, impregnated paper, and coated paper; Metal foils such as copper; foams such as urethane foam and polyethylene foam; polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; cellulose films such as polyurethane films, polyethylene films, polypropylene films, and triacetyl cellulose; Polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, acrylic resin film, norbornene resin film , A plastic film such as a cycloolefin resin film; and the like of two or more kinds of those laminates. The plastic film may be uniaxially stretched or biaxially stretched.

  The thickness of the substrate varies depending on the type thereof, but is usually 5 to 500 µm, preferably 10 to 300 µm, and particularly preferably 20 to 150 µm.

  As an example of the method for producing a pressure-sensitive adhesive sheet according to the present embodiment, a coating solution of the pressure-sensitive adhesive composition P is applied to a release surface of a release sheet, and a heat treatment is performed to form a coating film. Laminate another release sheet (with the release surface in contact with the coating) or substrate on the coating. The coating film becomes an adhesive layer as it is when a curing period is not required, and becomes an adhesive layer after the curing period has elapsed when a curing period is required. The conditions of the heat treatment and the curing are as described above.

  As a method of applying the coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used.

  The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet according to the present embodiment preferably has a haze value (a value measured according to JIS K7136: 2000) of 2% or less, and particularly preferably 1% or less. When the haze value is 2% or less, the transparency is very high, and it is suitable for optical use.

(Optical film with adhesive layer)
The optical film with an adhesive layer according to the present embodiment includes an optical film and an adhesive layer laminated on at least one surface of the optical film. The pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive according to the embodiment described above, or is formed from the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to the embodiment described above. The thickness and physical properties of the pressure-sensitive adhesive layer are the same as those of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet described above.

  The optical film may be composed of a single layer or a plurality of layers. Examples of the optical film include, for example, a polarizer, a polarizing plate, a retardation plate, a composite polarizing plate such as a polarizing plate with a retardation plate, a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, and a half film. Transmission / reflection films, laminates thereof, and the like are included. Above all, an optical film including a polarizer is suitable as the optical film of the optical film with a pressure-sensitive adhesive layer according to the present embodiment from the viewpoint that the polarizer is easily shrunk, has a large dimensional change, and requires durability. In particular, a thin polarizing plate in which the protective layer is reduced in thickness, and a composite polarizing plate using the polarizing plate has a weak force of suppressing the shrinkage of the polarizer by the protective layer, so that the polarizer is easily contracted by heat or the like. It is optimal as an optical film of the optical film with a pressure-sensitive adhesive layer according to the present embodiment.

  Here, the surface of the optical film in contact with the pressure-sensitive adhesive layer may be made of an acrylic resin. Further, the outermost layer in contact with the pressure-sensitive adhesive layer in the optical film may be formed of an acrylic resin layer formed through extrusion molding. Such an acrylic resin and a conventionally known pressure-sensitive adhesive layer have low adhesion and low durability, but according to the pressure-sensitive adhesive layer according to the present embodiment, the adhesive strength to the acrylic resin is high, and Excellent stress relaxation. Therefore, it has excellent durability even under high temperature conditions, wet heat conditions, under heat shock and the like. The “acrylic resin layer formed through extrusion molding” also includes an acrylic resin layer obtained by stretching after extrusion molding.

1. Example of Optical Film with Polarizing Plate An example of the optical film with a pressure-sensitive adhesive layer according to the present embodiment when the optical film is a polarizing plate will be described with reference to FIG. As shown in FIG. 1, the optical film with an adhesive layer 10A according to the present embodiment includes a polarizing plate 2A and an adhesive layer 1 laminated on one surface (the lower surface in FIG. 1) of the polarizing plate 2A. And is provided. Although not shown, a release sheet may be laminated on the surface of the pressure-sensitive adhesive layer 1 opposite to the side of the polarizing plate 2A until the optical film with a pressure-sensitive adhesive layer 10A is used.

  The pressure-sensitive adhesive layer 1 is formed from the pressure-sensitive adhesive according to the present embodiment described above.

  The polarizing plate 2A in the present embodiment includes a polarizer 21, a first protective layer 22 laminated on one surface (the upper surface in FIG. 1) of the polarizer 21, and the other surface of the polarizer 21 (see FIG. 1). 1 includes a second protective layer 23 laminated on the lower surface). Although not shown, an adhesive layer may be interposed between the polarizer 21 and the first protective layer 22 and / or between the polarizer 21 and the second protective layer 23.

(1) Polarizer The polarizer 21 is preferably made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented.

  The polyvinyl alcohol-based resin constituting the polarizer 21 is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Other monomers copolymerized with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and the like.

  The saponification degree of the polyvinyl alcohol-based resin is usually in the range of 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is generally in the range of 1,000 to 10,000, preferably in the range of 1,500 to 5,000.

  The polarizer 21 as described above includes a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and a step of adsorbing the dichroic dye. It is preferably manufactured through a step of treating the adsorbed polyvinyl alcohol-based resin film with an aqueous boric acid solution.

  Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or may be performed after dyeing with a dichroic dye. When the uniaxial stretching is performed after the dyeing with the dichroic dye, the uniaxial stretching may be performed before the boric acid treatment or may be performed during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural steps. For uniaxial stretching, the film may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, dry stretching in which stretching is performed in the air or wet stretching in which stretching is performed in a state of being swollen by a solvent may be employed. The stretching ratio is usually about 4 to 8 times.

  In order to dye a polyvinyl alcohol-based resin film with a dichroic dye, for example, the polyvinyl alcohol-based resin film may be immersed in an aqueous solution containing a dichroic dye. As the dichroic dye, specifically, iodine or a dichroic organic dye is used.

  When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide and dyeing is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight per 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 10 parts by weight per 100 parts by weight of water. It is. The temperature of this aqueous solution is usually about 20 to 40 ° C., and the immersion time (dying time) in this aqueous solution is usually about 30 to 300 seconds.

  Boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid aqueous solution. The content of boric acid in the boric acid aqueous solution is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is usually about 2 to 20 parts by mass, preferably 5 to 15 parts by mass per 100 parts by mass of water. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C.

  The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. After the water washing, a drying treatment is performed, and the polarizer 21 is obtained. The temperature of the water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 2 to 120 seconds. The subsequent drying treatment is usually performed using a hot-air dryer or a far-infrared heater. The drying temperature is usually 40 to 100C. The time for the drying process is usually about 120 to 600 seconds.

  The thickness of the polarizer 21 is preferably about 3 to 50 μm, and particularly when it is required to reduce the thickness, it is preferably about 3 to 15 μm.

(2) Protective Layer The first protective layer 22 and the second protective layer 23 (hereinafter sometimes collectively referred to as “protective layers 22 and 23”) are preferably made of a transparent resin film. The transparent resin film constituting the protective layers 22 and 23 may be an unstretched film or a uniaxially or biaxially stretched film.

  The main component of the transparent resin film is preferably at least one resin selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin, an amorphous polyolefin resin and a cellulose resin.

  As the amorphous polyolefin resin used for the protective layers 22 and 23, a cycloolefin resin is preferable. Examples of the cycloolefin-based resin include, for example, a resin obtained by performing ring-opening metathesis polymerization using norbornene or a derivative thereof obtained by a Diels-Alder reaction from cyclopentadiene and an olefin as a monomer, followed by hydrogenation; dicyclopentadiene; A resin obtained by performing ring-opening metathesis polymerization using olefins or methacrylic esters with tetracyclododecene or a derivative thereof obtained by a Diels-Alder reaction as a monomer, followed by hydrogenation; norbornene, tetracyclododecene and A resin obtained by conducting ring-opening metathesis copolymerization in the same manner using two or more kinds selected from derivatives of the above and other cyclic polyolefin monomers, followed by hydrogenation; norbornene, tetrane Kurododesen or their derivatives, resins obtained by addition copolymerization of aromatic compounds and the like having a vinyl group. Examples of commercially available amorphous polyolefin-based resins include "ARTON" of JSR Corporation, "ZEONEX" and "ZEONOR" of Zeon Corporation, "APO" and "APO" of Mitsui Chemicals, Inc. Appel ". When the amorphous polyolefin-based resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used for the film formation.

  The cellulose-based resin is a resin in which at least a part of the hydroxyl groups in cellulose is acetic acid esterified, and a part thereof is acetic esterified, and a mixed ester in which part is esterified with another acid. Good. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetyl cellulose resin. Specific examples of the acetylcellulose-based resin include triacetylcellulose, diacetylcellulose, cellulose acetate propionate, and cellulose acetate butyrate. Commercially available products made of such acetylcellulose-based films include, for example, “Fujitac TD80”, “Fujitak TD80UF” and “Fujitak TD80UZ” manufactured by Fujifilm Corporation, and “KC8UX2M” manufactured by Konica Minolta Opto, Inc. "," KC2UA ", and" KC8UY ".

  A cellulose-based resin film provided with an optical compensation function can also be used. As such an optical compensation film, for example, a film in which a compound having a retardation adjusting function is added to a cellulose resin, a film in which a compound having a retardation adjusting function is applied to the surface of a cellulose resin, A film obtained by stretching the film in an axial direction is exemplified. Examples of commercially available cellulose-based resin optical compensation films include "Wide View Film WV BZ 438" and "Wide View Film WV EA" manufactured by FUJIFILM Corporation, and "Wide View Film WV EA" manufactured by Konica Minolta Opto, Inc. KC4FR-1 "and" KC4HR-1 ".

  The protective layers 22 and 23 may contain an ultraviolet absorber. This is because the liquid crystal cell can be protected from deterioration due to ultraviolet light by disposing the protective layer containing the ultraviolet absorber on the viewing side of the liquid crystal cell.

  Here, the first protective layer 22 and the second protective layer 23 may be made of the same type of transparent resin film, or may be made of different types of transparent resin films.

  Prior to lamination to the polarizer 21, the protective layers 22 and 23 may be subjected to an easy adhesion treatment such as a saponification treatment, a corona treatment, a primer treatment, and an anchor coating treatment. Further, on the surface of the protective layer 22, 23 opposite to the surface to be bonded to the polarizer 21, various treatment layers such as a hard coat layer, an anti-reflection layer, and an anti-glare layer may be provided.

  The thickness of the protective layers 22 and 23 is generally in the range of about 5 to 200 μm, preferably 10 to 120 μm, particularly preferably 10 to 85 μm, and more preferably 10 to 30 μm.

  Among the above, the first protective layer 22 is preferably made of a cellulose resin, more preferably made of a cellulose ester resin, particularly preferably made of an acetylcellulose resin, and more preferably made of triacetyl cellulose. preferable.

  The second protective layer 23 is preferably made of an amorphous polyolefin-based resin among the above, and is particularly preferably made of the above-mentioned cycloolefin-based resin. Also in this case, the pressure-sensitive adhesive layer 1 has a high adhesive force to the second protective layer 23, and therefore, the optical film 10A with the pressure-sensitive adhesive layer has high durability under high-temperature conditions, wet-heat conditions, and heat shock. Excellent.

(3) Adhesive layer Adhesive constituting an adhesive layer which may be interposed between the polarizer 21 and the first protective layer 22 and / or between the polarizer 21 and the second protective layer 23. Any appropriate material can be used depending on the type and purpose of the adherend. For example, solvent-based adhesives, emulsion-based adhesives, water-based adhesives, pressure-sensitive adhesives, rewetting adhesives, polycondensation-type adhesives, solvent-free adhesives, film-like adhesives, hot-melt-type adhesives, and the like. No.

  One preferable adhesive constituting the above-mentioned adhesive is a water-based adhesive, a typical example of which is mainly composed of a polyvinyl alcohol-based resin. As a commercially available polyvinyl alcohol-based resin that can be used as an aqueous adhesive, for example, "KL-318" manufactured by Kuraray Co., Ltd. and the like are available.

  The water-based adhesive may contain a crosslinking agent. As the crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt and the like are preferable, and an epoxy compound is particularly preferable. Commercial products of the cross-linking agent include, for example, Glyoxal and "Smilease Resin 650 (30)" which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Co., Ltd.

  As another preferable adhesive, an adhesive composed of an epoxy resin composition containing an epoxy resin which is cured by irradiation with active energy rays or heating is used. When the adhesive is used, the adhesion between the films is performed by irradiating or heating an active energy ray to the adhesive layer interposed between the films to cure the curable epoxy resin contained in the adhesive. It can be done by doing. Curing of the epoxy resin by irradiation with active energy rays or heating is preferably performed by cationic polymerization of the epoxy resin. In addition, in this specification, an epoxy resin means a compound having two or more epoxy groups in a molecule.

  From the viewpoints of weather resistance, refractive index, cationic polymerizability and the like, the epoxy resin contained in the curable epoxy resin composition as the adhesive is preferably an epoxy resin containing no aromatic ring in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

(4) Manufacturing Method of Polarizing Plate The manufacturing of the polarizing plate 2A can be performed by a usual method. Hereinafter, as an example, a manufacturing method when a water-based adhesive is used as the adhesive will be described.

  First, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surfaces of the protective layers 22 and 23. For forming the adhesive layer, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used. Alternatively, a method in which the polarizer 21 and the protective layers 22 and 23 are continuously supplied such that the bonding surfaces of the polarizer 21 and the protective layer 22 are on the inside, and the adhesive is cast between them may be employed. After the application of the adhesive, a heat treatment is applied as necessary to evaporate the water and dry the adhesive layer.

  The thickness of the adhesive layer can be arbitrarily set depending on the characteristic design of the polarizing plate 2A. However, from the viewpoint of reducing the cost of the adhesive material, the smaller the thickness, the more preferable. From the viewpoint of adhesion and durability, it is preferable to carry out the process within an optimum range determined for each combination of the adherend and the adhesive. Generally, it is 0.005 to 10 μm, preferably 0.01 to 5 μm, and more preferably 0.03 to 1 μm.

  In bonding the polarizer 21 and the protective layers 22 and 23, a corona discharge treatment, a plasma treatment, a flame treatment, and a primer treatment are performed on one or both of the bonding surfaces of the two before forming an adhesive coating layer. An easy adhesion treatment such as an anchor coating treatment may be performed.

  After forming the adhesive layer as described above, the first protective layer 22 is bonded to one surface of the polarizer 21 via the adhesive layer, and the second protective layer 23 is To the other side. Thereby, a polarizing plate 2A obtained by laminating the first protective layer 22, the polarizer 21, and the second protective layer 23 is obtained.

  The total thickness of the polarizing plate 2A is usually about 15 to 400 μm, preferably 20 to 100 μm, and more preferably 30 to 80 μm from the viewpoint of maintaining the polarization performance while responding to the demand for thinner mobile applications. Is particularly preferred.

(5) Method for Manufacturing Optical Film with Adhesive Layer As an example of the method for manufacturing the optical film with an adhesive layer 10A, a release sheet is laminated on both sides of the adhesive layer as the above-described adhesive sheet according to the present embodiment. An adhesive sheet is prepared, and one release sheet (light release type release sheet) is released. Then, the second protective layer 23 of the polarizing plate 2A is overlaid on the exposed adhesive layer, and the adhesive sheet and the polarizing plate 2A are pressed. Thereby, the optical film 10A with an adhesive layer (with a release sheet) is obtained.

  As another example of the method for producing the optical film with an adhesive layer 10A, a solution (coating solution) containing the above-described adhesive composition P is applied to the release surface of a release sheet, and a heat treatment is performed to form a coating film. After the formation, the second protective layer 23 of the polarizing plate 2A is overlaid on the coating film. When a curing period is required, a curing period is provided. When the curing period is not required, the above-mentioned coating film becomes the pressure-sensitive adhesive layer 1 as it is. Thereby, the optical film 10A with an adhesive layer (with a release sheet) is obtained.

2. Example of Optical Film as Composite Polarizing Plate An example of the optical film with a pressure-sensitive adhesive layer according to the present embodiment when the optical film is a composite polarizing plate having a retardation plate will be described with reference to FIG. As shown in FIG. 2, the optical film with an adhesive layer 10B according to the present embodiment includes a composite polarizing plate 2B and an adhesive laminated on one surface (the lower surface in FIG. 2) of the composite polarizing plate 2B. And a layer 1. Although not shown, a release sheet may be laminated on the surface of the pressure-sensitive adhesive layer 1 opposite to the composite polarizing plate 2B side until the optical film with a pressure-sensitive adhesive layer 10B is used.

  The pressure-sensitive adhesive layer 1 is formed from the pressure-sensitive adhesive according to the present embodiment described above.

  The composite polarizing plate 2 </ b> B according to the present embodiment includes a first retardation plate 24 in contact with the pressure-sensitive adhesive layer 1, and a second position plate located on a side of the first retardation plate 24 opposite to the side of the pressure-sensitive adhesive layer 1. A phase difference plate 25, a second pressure-sensitive adhesive layer 26 interposed between the first phase difference plate 24 and the second phase difference plate 25, and a second pressure-sensitive adhesive layer 26 side of the second phase difference plate 25. And a protective layer 27 laminated on the side of the polarizer 21 opposite to the second retardation plate 25 side. Although not shown, an adhesive layer may be interposed between the polarizer 21 and the protective layer 27 and / or between the polarizer 21 and the second retardation plate 25. Such a composite polarizing plate 2B exhibits good viewing angle compensation performance.

(1) First retardation plate The first retardation plate 24 may be composed of a single layer that develops a phase difference, or may be composed of a plurality of layers including a phase difference development layer. The first retardation plate 24 is preferably, as shown in FIG. 3, a retardation expression layer 242 and a first layer which is laminated on one surface (the lower surface in FIG. 3) of the retardation expression layer 242. One acrylic resin layer 241 and a second acrylic resin layer 243 laminated on the other surface (the upper surface in FIG. 3) of the retardation expression layer 242. The phase difference expression layer 242 is preferably made of a styrene resin. As described above, the first retardation plate 24 including the first acrylic resin layer 241, the phase difference expression layer 242 made of styrene resin, and the second acrylic resin layer 243 is provided. The composite polarizing plate 2B is excellent in viewing angle compensation performance of a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device. Further, since the retardation manifestation layer 242 is protected by the first acrylic resin layer 241 and the second acrylic resin layer 243 present on both surfaces thereof, the first retardation plate 24 has mechanical strength and resistance to resistance. Excellent chemical properties.

  Further, the first retardation plate 24 is preferably provided with in-plane retardation by stretching. Thereby, the performance of the viewing angle compensation becomes more excellent.

  The styrene-based resin constituting the retardation developing layer 242 may be a homopolymer of styrene or a derivative thereof, or a binary or higher copolymer of styrene or a derivative thereof and another copolymerizable monomer. It may be united. A styrene derivative is a compound in which another group is bonded to styrene, for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, p-ethyl Alkyl styrene such as styrene, hydroxy styrene, tert-butoxy styrene, vinyl benzoic acid, o-chlorostyrene, p-chlorostyrene, etc., a hydroxyl group, alkoxy group, carboxyl group, halogen, etc. are introduced into the benzene nucleus of styrene. Substituted styrene and the like.

  As the styrene-based resin, a terpolymer disclosed in JP-A-2003-50316 or JP-A-2003-207640 can also be used.

  The styrene-based resin constituting the phase difference developing layer 242 is preferably a copolymer of styrene or a styrene derivative and at least one monomer selected from acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene.

  Further, as the styrene-based resin constituting the phase difference expression layer 242, a styrene-based resin having heat resistance is preferable. The glass transition temperature (Tg) of the styrene resin is generally 100 ° C. or higher, but a styrene resin having a glass transition temperature (Tg) of 120 ° C. or higher is preferable.

  The thickness of the phase difference expression layer 242 is preferably from 10 to 100 μm. When the thickness of the retardation developing layer 242 is 10 μm or more, a sufficient retardation value is developed by stretching. On the other hand, when the thickness of the phase difference expression layer 242 is 100 μm or less, the impact strength is high, the retardation change due to external stress is small, and when applied to a liquid crystal display device, heat unevenness and the like hardly occur.

  The first acrylic resin layer 241 and the second acrylic resin layer 243 are preferably made of a (meth) acrylic resin composition in which rubber particles are mixed with a (meth) acrylic resin. By blending the rubber particles, the impact resistance of the acrylic resin layer can be increased.

  Examples of the (meth) acrylic resin include a homopolymer of an alkyl methacrylate or an alkyl acrylate, and a copolymer of an alkyl methacrylate and an alkyl acrylate. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate and the like. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. As such a (meth) acrylic resin, those commercially available as general-purpose (meth) acrylic resins can be used. Some of the (meth) acrylic resins include those called impact-resistant (meth) acrylic resins and highly heat-resistant (meth) acrylic resins having a glutaric anhydride structure or a lactone ring structure in the main chain. What is called is also included.

  The rubber particles mixed with the (meth) acrylic resin are preferably acrylic. The acrylic rubber particles are particles having a rubber elasticity obtained by polymerizing an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer.

  The rubber particles may be made of a material having rubber elasticity in a uniform particle state, or may be a multilayer structure having at least one rubber elastic layer. Acrylic rubber particles having a multilayer structure include particles having the above rubber elasticity as a nucleus, the periphery of which is covered with a hard alkyl methacrylate polymer, and a hard alkyl methacrylate polymer. The core is covered with an acrylic polymer having rubber elasticity as described above, and the periphery of the hard core is covered with an acrylic polymer having rubber elasticity, and further around the core is hard methacrylic acid. Those covered with an alkyl ester polymer and the like can be mentioned.

  The average diameter of the rubber particles is preferably about 50 to 400 nm. The average diameter of the rubber particles can be measured by a laser diffraction scattering method.

  The content of the rubber particles in the (meth) acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243 is 5 to 100 parts by mass of the (meth) acrylic resin. It is preferably about 50 parts by mass.

  The (meth) acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243 is commercially available in a state where the (meth) acrylic resin and the acrylic rubber particles are mixed. Can be used. Examples of commercially available (meth) acrylic resins ((meth) acrylic resin compositions) containing acrylic rubber particles are “HT55X” sold by Sumitomo Chemical Co., Ltd. under the trade names. And "Technoloy S001".

  The glass transition temperature (Tg) of the (meth) acrylic resin composition is generally 160 ° C. or lower, but a (meth) acrylic resin composition having a glass transition temperature (Tg) of 120 ° C. or lower is preferable, and particularly 110 ° C. A (meth) acrylic resin composition at a temperature of not more than ° C is preferred. That is, it is preferable that the glass transition temperature (Tg) of the phase difference manifestation layer 242 does not overlap with the glass transition temperature (Tg) of the first acrylic resin layer 241 and the second acrylic resin layer 243. The layer 242 preferably has a higher glass transition temperature (Tg) than the first acrylic resin layer 241 and the second acrylic resin layer 243.

  The materials of the first acrylic resin layer 241 and the second acrylic resin layer 243 may be the same or different.

  The thickness of each of the first acrylic resin layer 241 and the second acrylic resin layer 243 is preferably 10 to 100 μm. When the thickness is 10 μm or more, the film can be easily formed. When the thickness is 100 μm or less, retardation of the first acrylic resin layer 241 and the second acrylic resin layer 243 is ignored. Can be. Note that the thickness of the first acrylic resin layer 241 and the thickness of the second acrylic resin layer 243 are preferably substantially the same.

  The surface of the first retardation plate 24 on the side of the second pressure-sensitive adhesive layer 26 may be subjected to a surface treatment such as a corona treatment.

  In order to manufacture the first retardation plate 24, for example, a styrene resin and a (meth) acrylic resin composition containing rubber particles may be co-extruded and then stretched. Stretching can be performed by longitudinal uniaxial stretching, tenter horizontal uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching, and may be performed so as to obtain a desired retardation value. In addition to the above-described method, after each of the single-layer films (the retardation expression layer 242, the first acrylic resin layer 241 and the second acrylic resin layer 243) is formed, they are thermally fused by heat lamination. Then, the laminate may be stretched.

  In addition, the total thickness of the first retardation plate 24 after stretching is preferably 5 to 100 μm, and more preferably 10 to 50 μm, from the viewpoint of meeting the demand for thinning in mobile applications while maintaining sufficient performance. Is more preferably, and particularly preferably 15 to 30 μm.

  In the first retardation plate 24, the surface in contact with the pressure-sensitive adhesive layer 1 is constituted by the first acrylic resin layer 241. In this case as well, the pressure-sensitive adhesive layer 1 is in contact with the first acrylic resin layer 241. The optical film 10B with an adhesive layer has high adhesive strength, and thus has excellent durability even under high-temperature conditions, wet-heat conditions, and under heat shock.

(2) Second retardation plate The second retardation plate 25 is preferably made of an olefin-based resin. The olefin-based resin is defined as a chain aliphatic olefin such as ethylene and propylene, or a structural unit derived from an alicyclic olefin such as norbornene or a substituted product thereof (hereinafter, also collectively referred to as a norbornene-based monomer). Resin. The olefin-based resin may be a copolymer using two or more monomers.

  Above all, as the olefin resin, a cyclic olefin resin which is a resin mainly containing a structural unit derived from an alicyclic olefin is preferably used. Typical examples of the alicyclic olefin constituting the cyclic olefin resin include a norbornene-based monomer. Norbornene is a compound in which one carbon-carbon bond of norbornane is a double bond, and according to IUPAC nomenclature, is named bicyclo [2,2,1] hept-2-ene. is there. Examples of the substituted norbornene include 3-substituted, 4-substituted, and 4,5-disubstituted compounds in which the double bond position of norbornene is 1,2-position. Cyclopentadiene, dimethanooctahydronaphthalene, and the like can also be used as monomers constituting the cyclic olefin-based resin.

  The cyclic olefin-based resin may or may not have a norbornane ring in its constituent unit. Examples of the norbornene-based monomer that forms a cyclic olefin-based resin having no norbornane ring in the structural unit include, for example, those that become a 5-membered ring by ring opening, typically, norbornene, dicyclopentadiene, 1- or 4- Methyl norbornene, 4-phenylnorbornene, and the like. When the cyclic olefin resin is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be a polymer.

  More specific examples of the cyclic olefin-based resin include, for example, a ring-opened polymer of a norbornene-based monomer, a ring-opened copolymer of a norbornene-based monomer and another monomer, and maleic acid addition or cyclopentadiene addition thereof. Examples of the modified polymer include a polymer or copolymer obtained by hydrogenating the polymer, an addition polymer of a norbornene-based monomer, and an addition copolymer of a norbornene-based monomer and another monomer. Other monomers in the case of forming a copolymer include α-olefins, cycloalkenes, non-conjugated dienes, and the like. Further, the cyclic olefin-based resin may be a copolymer using one or more of a norbornene-based monomer and another alicyclic olefin.

  Among the above specific examples, as the cyclic olefin-based resin, a resin obtained by hydrogenating a ring-opened polymer using a norbornene-based monomer is preferably used. Such a cyclic olefin-based resin can be subjected to a stretching treatment to give a retardation plate, and in addition to stretching, by applying a heat-shrinking treatment by bonding a shrinkable film having a predetermined shrinkage ratio, A phase difference plate having high uniformity and a large phase difference value can also be obtained.

  As commercial products of cyclic olefin-based resins using norbornene-based monomers, "Zeonex" and "Zeonor" sold by ZEON CORPORATION under the trade names, and "Zeonor" sold by JSR Corporation Arton "and the like. Commercially available products of these cyclic olefin-based resin films and stretched films thereof are also available. For example, “Zeonor Film” sold by ZEON Corporation and JSR Corporation There are "ARTON FILM" sold and "ESCINA" sold by Sekisui Chemical Co., Ltd.

  Further, as the second retardation plate 25, a film made of a mixed resin containing two or more kinds of olefin-based resins or a film made of a mixed resin of an olefin-based resin and another thermoplastic resin can be used. For example, as the mixed resin containing two or more olefin-based resins, a mixture of the above-described cyclic olefin-based resin and chain aliphatic olefin-based resin can be exemplified. When a mixed resin of an olefin-based resin and another thermoplastic resin is used, an appropriate thermoplastic resin is appropriately selected according to the purpose. Specific examples include polyvinyl chloride resin, cellulose resin, polystyrene resin, acrylonitrile / butadiene / styrene copolymer resin, acrylonitrile / styrene copolymer resin, (meth) acrylic resin, polyvinyl acetate resin, and polyvinyl chloride resin. Vinylidene resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyether Examples thereof include an ether ketone resin, a polyarylate resin, a liquid crystal resin, a polyamideimide resin, a polyimide resin, and a polytetrafluoroethylene resin. The thermoplastic resins can be used alone or in combination of two or more. Further, the thermoplastic resin can be used after any appropriate polymer modification. Examples of the polymer modification include copolymerization, cross-linking, molecular terminal modification, imparting stereoregularity, and the like.

  When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin is usually about 50% by mass or less, preferably about 40% by mass or less based on the whole resin. By setting the content of the other thermoplastic resin in this range, the absolute value of the photoelastic coefficient is small, showing good wavelength dispersion characteristics, and having excellent durability, mechanical strength, and transparency. Can be obtained.

  The olefin-based resin can be formed into a film by a casting method or a melt extrusion method from a solution. When a film is formed from a mixed resin of two or more types, the method for forming the film is not particularly limited. For example, a film is formed by a casting method using a uniform solution obtained by stirring and mixing a resin component with a solvent at a predetermined ratio. A production method, a method in which a resin component is melt-mixed at a predetermined ratio and a film is produced by a melt extrusion method, and the like are employed.

  The film made of the olefin-based resin may contain other components as necessary, such as a residual solvent, a stabilizer, a plasticizer, an antioxidant, an antistatic agent, and an ultraviolet absorber. In addition, a leveling agent may be contained in order to reduce the surface roughness.

  The surface of the second retardation plate 25 on the side of the second pressure-sensitive adhesive layer 26 may be subjected to a surface treatment such as a corona treatment.

Second retardation plate 25 has an in-plane slow axis direction, and the refractive index in the in-plane fast axis direction and the thickness direction respectively n _x, and n _y and n _z, when the thickness of the film is d, the following Equation (1):
_{R e = (n x -n y} ) × d (1)
In-plane retardation value _{R e} in the definition is the wavelength 590nm is 30 to 150 nm, the following formula (2):
Nz factor _{= (n x -n z) /} (n x -n y) (2)
Has an anisotropy of refractive index of more than 1 and less than 2.

  The second retardation plate 25 having the above-described refractive index anisotropy can be obtained by longitudinal uniaxial stretching, tenter horizontal uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching of a film made of the olefin resin. In addition to appropriately adjusting the stretching ratio and the stretching speed, a desired refractive index difference can be obtained by appropriately selecting various temperatures such as a preheating temperature during stretching, a stretching temperature, a heat setting temperature, a cooling temperature, and a pattern thereof. Anisotropy can be obtained.

  The thickness of the second retardation plate 25 is preferably in the range of 5 to 80 μm, more preferably in the range of 10 to 80 μm, and particularly preferably in the range of 10 to 30 μm.

(3) Second pressure-sensitive adhesive layer As the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26, a known pressure-sensitive adhesive can be used, and a curable pressure-sensitive adhesive or a non-curable pressure-sensitive adhesive may be used. Although an adhesive may be used, it is preferable to use an active energy ray-curable adhesive from the viewpoint of suppressing a dimensional change due to heat shrinkage of the polarizing plate.

  The active energy ray-curable pressure-sensitive adhesive may be mainly composed of a polymer having an active energy ray-curable property, or a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer and And / or a mixture mainly composed of a mixture with an oligomer. Further, it may be a mixture of a polymer having active energy ray curability and a polymer having no active energy ray curability, or a polymer having active energy ray curability and an active energy ray curable polyfunctional monomer and / or Alternatively, it may be a mixture with an oligomer, or a mixture of these three types.

  Among the above, from the viewpoint that it is easy to obtain a pressure-sensitive adhesive that exhibits cohesive strength while maintaining tackiness, a mixture of a polymer having no active energy ray-curable and an active energy ray-curable polyfunctional monomer and / or oligomer Preferably, the main component is a mixture of a polymer having no active energy ray curability and a polyfunctional monomer having an active energy ray curability.

  As the polymer having no active energy ray-curable property, a (meth) acrylate polymer having no active energy-ray-curable group (hereinafter, may be referred to as “(meth) acrylate polymer (X)”). Is preferred. The (meth) acrylate polymer (X) preferably contains, as a monomer constituting the polymer, an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms. As a result, the obtained pressure-sensitive adhesive can exhibit favorable tackiness. The (meth) acrylate polymer (X) is a monomer having a reactive functional group with a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group (reactive functional group-containing monomer). And a copolymer with other monomers used as desired. When the (meth) acrylate polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, it is possible to improve the adhesion to the glass surface of a liquid crystal cell or the like, Further, it can also form a crosslinked structure by reacting with a crosslinking agent (Z) described later.

  Examples of the alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n- (meth) acrylate. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate and the like. Among them, from the viewpoint of further improving the adhesiveness, (meth) acrylate having 1 to 8 carbon atoms in the alkyl group is preferable, and n-butyl (meth) acrylate is particularly preferable. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (X) may contain, as a monomer unit constituting the polymer, 50 to 99% by mass of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms. Preferably, it is contained in an amount of preferably from 60 to 99% by mass, and more preferably from 70 to 98% by mass.

  Examples of the reactive functional group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), and a monomer having an amino group in the molecule (amino group-containing monomer). Monomer) and the like. One of these reactive functional group-containing monomers may be used alone, or two or more thereof may be used in combination.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth) acrylate. ) Hydroxyalkyl (meth) acrylates such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate.

  Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. Above all, acrylic acid is preferred from the viewpoint of the reactivity of the carboxyl group in the obtained (meth) acrylate polymer (X) with the crosslinking agent (Z) and the copolymerizability with other monomers. These may be used alone or in combination of two or more.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, n-butylaminoethyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  The (meth) acrylate polymer (X) preferably contains a reactive functional group-containing monomer in an amount of 1 to 25% by mass, more preferably 1 to 20% by mass, as a monomer unit constituting the polymer. And more preferably 2 to 5% by mass.

  The polymerization mode of the (meth) acrylate polymer (X) may be a random copolymer or a block copolymer.

  The weight average molecular weight of the (meth) acrylate polymer (X) is preferably from 300,000 to 3,000,000, particularly preferably from 1,000,000 to 2.5,000,000, and more preferably from 1.6,000,000 to 2.2,000,000. preferable.

  The (meth) acrylate polymer (X) may be used alone or in a combination of two or more.

  As the active energy ray-curable polyfunctional monomer, a polyfunctional acrylate monomer having a molecular weight of 1,000 or less and excellent in compatibility with the (meth) acrylate polymer (X) and the like is preferable.

  Examples of the polyfunctional acrylate monomer having a molecular weight of 1,000 or less include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol di. (Meth) acrylate, neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified Bifunctional type such as di (meth) acrylate phosphate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate; trimethylolpropane tri (meth) acryl , Dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) Trifunctional types such as isocyanurate and ε-caprolactone-modified tris- (2- (meth) acryloxyethyl) isocyanurate; tetrafunctional types such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; propionic acid 5-functional type such as modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate And six functional types such as These may be used alone or in combination of two or more.

  The content of the active energy ray-curable compound (Y) is preferably from 1 to 50 parts by mass, more preferably from 5 to 30 parts by mass, based on 100 parts by mass of the (meth) acrylate polymer (X). It is preferable that the amount is more preferably 10 to 20 parts by mass.

  It is also preferable that the active energy ray-curable pressure-sensitive adhesive contains a crosslinking agent (Z). When the active energy ray-curable pressure-sensitive adhesive contains a (meth) acrylate polymer (X) containing a reactive functional group-containing monomer as a monomer unit constituting the polymer, and a crosslinking agent (Z), When the pressure-sensitive adhesive is heated or the like, the cross-linking agent (Z) reacts with the reactive functional group of the reactive functional group-containing monomer constituting the (meth) acrylate polymer (X). Thereby, a structure in which the (meth) acrylate polymer (X) is cross-linked by the cross-linking agent (Z) is formed, and the cohesive force of the obtained pressure-sensitive adhesive is improved.

  The crosslinking agent (Z) may be any as long as it reacts with the reactive functional group of the (meth) acrylate polymer (X). For example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, and an amine-based crosslinking agent , Melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, ammonium salt-based crosslinking agents, etc. Is mentioned. As the isocyanate-based cross-linking agent, the same as the above-mentioned isocyanate-based cross-linking agent (B) can be used. In addition, the crosslinking agent (Z) can be used alone or in combination of two or more.

  The content of the crosslinking agent (Z) is preferably from 0.01 to 10 parts by mass, particularly preferably from 0.05 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylate polymer (X). Preferably, the amount is 0.1 to 1 part by mass.

  The active energy ray-curable pressure-sensitive adhesive may be, if desired, various additives, for example, a photopolymerization initiator, a silane coupling agent, a refractive index adjuster, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, and light. It may contain stabilizers, softeners, fillers and the like.

  When ultraviolet rays are used as active energy rays for curing the active energy ray-curable pressure-sensitive adhesive, the active energy ray-curable pressure-sensitive adhesive preferably contains a photopolymerization initiator.

  Examples of the photopolymerization initiator include, for example, bensoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylamido Benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-Diethylthioxanthone, benzyldimethylketal, acetophenonedimethylketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4 , 6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

  The photopolymerization initiator is used in an amount of 0.1 to 20 parts by mass, particularly 1 to 12 parts by mass, based on 100 parts by mass of the active energy ray-curable compound (Y) in the active energy ray-curable pressure-sensitive adhesive. It is preferable to use them.

  The active energy ray-curable pressure-sensitive adhesive preferably contains a silane coupling agent from the viewpoint of improving the adhesion of the obtained pressure-sensitive adhesive to a film. The silane coupling agent is preferably an organosilicon compound having at least one alkoxysilyl group in the molecule, having good compatibility with the adhesive component and having light transmittance.

  Examples of such a silane coupling agent include, in addition to the aforementioned epoxy group-containing silane coupling agent (D1) and mercapto group-containing silane coupling agent (D2), vinyl trimethoxysilane, vinyl triethoxysilane, methacryloxypropyl trisilane. Polymerizable unsaturated group-containing silicon compound such as methoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-amino Amino group-containing silicon compounds such as propylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these, and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane Emissions, such as condensation products of alkyl group-containing silicon compounds such as ethyl trimethoxysilane. These may be used alone or in combination of two or more.

  The content of the silane coupling agent is preferably 0.01 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the (meth) acrylate polymer (X). And more preferably 0.1 to 1 part by mass.

  The active energy ray-curable polymer is a (meth) acrylate (co) polymer having a functional group (active energy ray-curable group) having an active energy ray-curable side chain introduced therein. Is preferred.

  The thickness of the second pressure-sensitive adhesive layer 26 is generally about 1 to 50 μm, preferably 1 to 20 μm, and particularly preferably 2 to 7 μm. If the pressure-sensitive adhesive layer is too thin, the adhesiveness is reduced.

(4) Polarizer As the polarizer 21, the same polarizer as the polarizer 21 of the polarizing plate 2A described above can be used.

(5) Protective Layer The protective layer 27 is preferably made of a transparent resin film. As this protective layer 27, the same one as the first protective layer 22 in the polarizing plate 2A can be used.

(6) Adhesive Layer The adhesive layer that may be interposed between the polarizer 21 and the protective layer 27 and / or between the polarizer 21 and the second retardation plate 25 is the same as the above-described polarizing plate 2A. The same adhesive layer as described above can be used.

(7) Manufacturing Method of Composite Polarizing Plate The manufacturing of the composite polarizing plate 2B can be performed by an ordinary method. Hereinafter, as an example, a manufacturing method when a water-based adhesive is used as the adhesive will be described.

  First, a coating film of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26 is formed on the release surface of the release sheet. Specifically, a coating solution of the adhesive constituting the second adhesive layer 26 is applied to the release surface of the release sheet and dried.

  On the other hand, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surfaces of the second retardation plate 25 and the protective layer 27. The formation of the adhesive layer can be performed in the same manner as in the method of manufacturing the polarizing plate 2A described above. The same applies to the thickness of the adhesive layer and the easy adhesion treatment.

  After forming the adhesive layer as described above, the protective layer 27 is bonded to one surface of the polarizer 21 via the adhesive layer, and the second retardation plate 25 is connected to the other side of the polarizer 21. To obtain a laminate (polarizing plate) including the protective layer 27, the polarizer 21, and the second retardation plate 25.

  Next, on the surface on the second retardation plate 25 side of the obtained laminate, a coating film of an adhesive constituting the second adhesive layer 26 on the release sheet is bonded. Then, the adhesive film is cured by irradiating an active energy ray over the release sheet, and the coated film is used as the second adhesive layer 26.

  Here, the active energy beam refers to a beam having an energy quantum among electromagnetic waves or charged particle beams, and specific examples include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays which are easy to handle are particularly preferable.

Irradiation with ultraviolet rays can be performed by a high-pressure mercury lamp, a metal halide lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of the ultraviolet rays is preferably about 50 to 1000 mW / cm ² . Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 100~1000mJ / cm ^2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1,000 krad.

  Finally, the release sheet is peeled from the second pressure-sensitive adhesive layer 26 formed as described above, and the second acrylic resin layer 243 in the first retardation plate 24 is applied to the exposed second pressure-sensitive adhesive layer 26. Glue the sides. Thus, a composite polarizing plate 2B obtained by laminating the protective layer 27, the polarizer 21, the second retardation plate 25, the second pressure-sensitive adhesive layer 26, and the first retardation plate 24 is obtained.

  In addition, the total thickness of the composite polarizing plate 2B is preferably 20 to 300 μm, more preferably 30 to 150 μm, and particularly preferably 50 to 100 μm.

(8) Method of Manufacturing Optical Film with Adhesive Layer As an example of the method of manufacturing the optical film with an adhesive layer 10B, a release sheet is laminated on both sides of the adhesive layer as the above-described adhesive sheet according to the present embodiment. An adhesive sheet is prepared, and one release sheet (light release type release sheet) is released. Then, the first retardation plate 24 of the composite polarizing plate 2B is overlaid on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the composite polarizing plate 2B are pressed. Thereby, the optical film 10B with a pressure-sensitive adhesive layer (with a release sheet) is obtained.

  As another example of the method of manufacturing the optical film with an adhesive layer 10B, the coating solution of the above-described adhesive composition P is applied to the release surface of a release sheet, and a heat treatment is performed to form a coating film. The first retardation plate 24 of the composite polarizing plate 2B is overlaid on the coating film. When a curing period is required, a curing period is provided. When the curing period is not required, the above-mentioned coating film becomes the pressure-sensitive adhesive layer 1 as it is. Thereby, the optical film 10B with a pressure-sensitive adhesive layer (with a release sheet) is obtained.

3. Physical Properties of Optical Film with Pressure-Sensitive Adhesive Layer The surface resistivity of the pressure-sensitive adhesive layers in the optical films with pressure-sensitive adhesive layers 10A and 10B according to the present embodiment is preferably 1.0 × 10 ¹² Ω / sq or less, particularly preferably 5 × 10 ¹² Ω / sq or less. It is preferably not more than 6.0 × 10 ¹¹ Ω / sq, and more preferably not more than 6.0 × 10 ¹⁰ Ω / sq. When the surface resistivity is equal to or less than the above value, a sufficient antistatic property can be exhibited in the display panel. Such a surface resistivity can be achieved when the adhesive composition P contains an antistatic agent (C). The measurement of the surface resistivity of the pressure-sensitive adhesive layer is performed according to JIS K6911, and is specifically as shown in a test example described later. The lower limit of the surface resistivity is not particularly limited, but is about 5.0 × 10 ⁸ Ω / sq from the viewpoint of not adversely affecting durability and heat resistance unevenness.

  The adhesive strength of the optical films with an adhesive layer 10A, 10B according to the present embodiment is preferably such that the adhesive strength to alkali-free glass is 0.5 to 20 N / 25 mm, particularly 1 to 10 N / 25 mm. preferable. Thereby, the optical film with the pressure-sensitive adhesive layer has excellent durability. Further, from the viewpoint of excellent reworkability, the adhesive strength is preferably 2 to 7 N / 25 mm. The adhesive force referred to here is basically the adhesive force measured by a 180 ° peeling method according to JIS Z0237: 2009, and the measurement sample is 25 mm wide and 100 mm long. After applying to the body by applying a pressure of 0.5 MPa and 50 ° C. for 20 minutes, leaving it for 24 hours under the conditions of normal pressure, 23 ° C. and 50% RH, measure at a peeling rate of 300 mm / min. I do. When the adhesive strength is within the above range, floating or peeling can be prevented when the liquid crystal cell is adhered.

  In addition, the optical films 10A and 10B with an adhesive layer according to the present embodiment are further attached to the adherend, and then left to stand at 23 ° C. and 50% RH for 14 days. Is preferably 1 to 20 N / 25 mm, and more preferably 3 to 9 N / 25 mm. Since the increase in the adhesive force due to aging is suppressed in this manner, the optical films with an adhesive layer 10A and 10B according to the present embodiment have excellent reworkability and can be easily re-attached even after being attached to the liquid crystal cell. be able to.

4. Use of Optical Film with Pressure-Sensitive Adhesive Layer By using the optical films with pressure-sensitive adhesive layers 10A and 10B, for example, a liquid crystal display device including a liquid crystal cell and an optical film (a polarizing plate or a composite polarizing plate) can be manufactured. it can.

  Specifically, the pressure-sensitive adhesive layers of the optical films 10A and 10B with a pressure-sensitive adhesive layer (in the case where a release sheet is laminated, the pressure-sensitive adhesive layer exposed by peeling off the release sheet) are applied to a desired liquid crystal cell. What is necessary is just to overlap and crimp on a surface. Thereby, a liquid crystal display device including the liquid crystal cell and the polarizing plate 2A and / or the composite polarizing plate 2B is obtained.

  The pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive layer-attached optical films 10A and 10B according to the present embodiment exhibits good antistatic properties, and thus can suppress generation of static electricity when the release sheet is peeled off. Therefore, when the optical films with an adhesive layer 10A and 10B are bonded to the liquid crystal cell as described above, there is no possibility that the alignment of the liquid crystal molecules in the liquid crystal cell is disturbed, and dust or dust due to static electricity is not generated. It is possible to prevent the liquid crystal display device from entering the liquid crystal display device.

  The pressure-sensitive adhesive layer 1 of the optical film with a pressure-sensitive adhesive layer 10A, 10B according to the present embodiment is excellent in durability, so that the obtained liquid crystal display device can be used under high temperature conditions, wet heat conditions, or heat shock. The occurrence of lifting and peeling at the interface of the layer 1 is suppressed. For example, when the glass plate to which the optical films with adhesive layers 10A and 10B are attached is placed under a high temperature condition of 85 ° C. or a wet heat condition of 60 ° C./90% RH for 250 hours, or a heat of −35 ° C. to 70 ° C. Even when a shock (each 30 minutes, 200 cycles) is given, the occurrence of floating and peeling is suppressed.

  Further, since the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive layer-attached optical films 10A and 10B according to the present embodiment also has excellent stress relaxation properties, the obtained liquid crystal display device is unlikely to be warped even under high temperature conditions, and furthermore, has uneven heat. Is unlikely to occur. For example, even when the glass plate to which the optical films with adhesive layers 10A and 10B are adhered is placed under a high temperature condition (for example, a condition of 80 to 85 ° C.) for 250 hours, the glass plate is hardly warped and heat unevenness is hardly generated. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a thin film, the liquid crystal display device does not easily warp, and even if the liquid crystal cell has a high definition, heat unevenness does not easily occur.

  Here, a transparent conductive film may be present on the surface of the liquid crystal cell to be bonded to the pressure-sensitive adhesive layer 1, and even in this case, the transparent conductive film is corroded or the resistance of the transparent conductive film changes. Is suppressed. In particular, in the present embodiment, the above effects are obtained by using the (meth) acrylate copolymer (A) having an acid value of 5 mgKOH / g or less and using the specific antistatic agent (C). It is fully demonstrated.

  Examples of the transparent conductive film include metals such as platinum, gold, silver, copper, and aluminum, tin oxide, indium oxide, cadmium oxide, oxides such as zinc oxide and zinc dioxide, tin-doped indium oxide (ITO), and zinc oxide. Compound oxides such as doped indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, and non-oxidized compounds such as chalcogenide, lanthanum hexaboride, titanium nitride, and titanium carbide Is mentioned.

  The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  Hereinafter, the present invention will be described more specifically with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. Production of First Optical Film (Polarizing Plate) (1) Production of Polarizer A 75 μm-thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more was prepared. The film was uniaxially stretched about 5 times in a dry system, and further immersed in pure water at 60 ° C. for 1 minute while maintaining the tension. Then, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Then, it was immersed in an aqueous solution of potassium iodide / boric acid / water having a mass ratio of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Next, the substrate was washed with pure water at 26 ° C. for 20 seconds and dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented in polyvinyl alcohol.

(2) Preparation of Polarizing Plate 3 parts by mass of a carboxyl group-modified polyvinyl alcohol (trade name “KL-318” manufactured by Kuraray Co., Ltd.) is dissolved in 100 parts by mass of water, and the aqueous solution is a water-soluble epoxy resin. An epoxy-based adhesive was prepared by adding 1.5 parts by mass of a polyamide epoxy-based additive (trade name “SUMIREZ Resin 650 (30)”, an aqueous solution having a solid content of 30% by mass) manufactured by Taoka Chemical Industry Co., Ltd. . The epoxy adhesive was applied to one surface of the polarizer obtained above.

  A 25 μm-thick triacetylcellulose film (Konica Minolta Opto Co., Ltd., trade name “KC2UA”) having a surface treated with saponification as a first protective layer for the coating layer of the epoxy adhesive. Was pasted.

  Next, an epoxy-based adhesive is applied to the other surface of the polarizer in the same manner as described above, and a second protective layer made of a cyclic olefin-based resin having a thickness of 23 μm is used as a second protective layer. A phase difference film (manufactured by Nippon Zeon Co., Ltd., trade name “ZEONOR”) was bonded. Thereafter, by drying at 80 ° C. for 5 minutes, the first protective layer and the second protective layer were adhered to the polarizer. After bonding, curing is performed at 40 ° C. for 168 hours, and a first protective layer (layer thickness 25 μm), a polarizer (stretching magnification 5 times, layer thickness 15 μm) and a second protective layer (layer thickness 23 μm) are laminated. A polarizing plate (first optical film) having a total thickness of 63 μm was obtained.

2. Production of second optical film (composite polarizing plate) (1) Formation of coating film of active energy ray-curable pressure-sensitive adhesive 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid were copolymerized to obtain (meth) An acrylate polymer (X) was prepared. When the molecular weight of this (meth) acrylic acid ester polymer (X) was measured by the method described later, the weight average molecular weight (Mw) was 2,000,000.

  100 parts by mass of the (meth) acrylate polymer (X) and tris (acryloxyethyl) isocyanurate (trade name, manufactured by Toa Gosei Co., Ltd.) as an active energy ray-curable compound (Y) (polyfunctional monomer) Aronix M-315 ") 15 parts by mass, as a crosslinking agent (Z) 0.3 parts by mass of trimethylolpropane-modified tolylene diisocyanate (trade name" Coronate L ", manufactured by Nippon Polyurethane Industry Co., Ltd.), and as a polymerization initiator , A mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1: 1 (trade name “Irgacure 500” manufactured by Ciba Specialty Chemicals) and 1.5 parts by mass of silane coupling agent Glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name "KBM4 3 ") were mixed with 0.2 parts by mass, sufficiently stirred, by diluting with ethyl acetate to obtain a coating solution of the active energy ray-curable pressure-sensitive adhesive.

  The obtained coating solution of the active energy ray-curable pressure-sensitive adhesive was applied to a release-treated surface of a release sheet (manufactured by Lintec, SP-PET3811, thickness: 38 μm) in which one surface of a polyethylene terephthalate film was subjected to release treatment with a silicone-based release agent. Then, the mixture was applied with a knife coater and then heated at 90 ° C. for 1 minute to form a coating film of the active energy ray-curable pressure-sensitive adhesive.

(2) Preparation of First Retardation Plate Methacrylic resin (about 20% by mass) of acrylic rubber particles having an average particle diameter of 200 nm constituting the first acrylic resin layer (manufactured by Sumitomo Chemical Co., Ltd. A trade name “Technoloy S001”), a styrene-maleic anhydride copolymer resin (trade name “Dailac D332”, manufactured by Nova Chemical Co., Ltd.) that constitutes the retardation developing layer, and a second acrylic resin layer A methacrylic resin (trade name “Technoloy S001” manufactured by Sumitomo Chemical Co., Ltd.) containing about 20% by mass of acrylic rubber particles having an average particle diameter of 200 nm is coextruded in three layers in this order to form a three-layer structure. Was obtained. The obtained laminated film is stretched, and a first retardation plate having an in-plane retardation value of 60 nm and a thickness of 25 μm (first acrylic resin layer / phase difference expression layer / second acrylic resin layer) I got

(3) Production of Composite Polarizing Plate First, the first optical film (polarizing plate) described above was prepared. The first protective layer and the second protective layer in the polarizing plate correspond to the protective layer and the second retardation plate in the composite polarizing plate manufactured here, respectively. That is, a polarizing plate was prepared by laminating a protective layer, a polarizer, and a second retardation plate.

A film of the active energy ray-curable pressure-sensitive adhesive obtained in the above step (1) is bonded to the surface of the polarizing plate on the side of the second retardation plate, and ultraviolet rays are applied through the release sheet under the following conditions. Irradiation was performed to cure the pressure-sensitive adhesive film to form a second pressure-sensitive adhesive layer. Thereafter, the release sheet is peeled from the obtained second pressure-sensitive adhesive layer, and the second surface of the first retardation plate obtained in the above step (2) is applied to the exposed surface of the second pressure-sensitive adhesive layer. The surface on the acrylic resin layer side was bonded. In this manner, a composite polarizing plate (second optical film) having a total thickness of 93 μm obtained by laminating the protective layer, the polarizer, the second retardation plate, the second pressure-sensitive adhesive layer, and the first retardation plate. I got Note that the thickness of the formed second pressure-sensitive adhesive layer was 5 μm.
<Ultraviolet irradiation conditions>
・ Use of high pressure mercury lamp ・ Illuminance 300mW / cm ² , Light intensity 300mJ / cm ²
・ UV illuminance and light meter use "UVPF-A1" manufactured by Eye Graphics

3. Production of optical film with pressure-sensitive adhesive layer (1) Preparation of (meth) acrylate copolymer 87 parts by mass of n-butyl acrylate, 5 parts by mass of isobornyl acrylate, 5 parts by mass of 2-phenylethyl acrylate and acrylic acid By copolymerizing 3 parts by mass of 2-hydroxyethyl, a (meth) acrylate copolymer (A) was prepared. When the molecular weight of this (meth) acrylate copolymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 1.6 million. The hydroxyl value of the (meth) acrylic acid ester copolymer (A) is calculated to be 14.49 mgKOH / g, and the acid value is calculated to be 0 mgKOH / g from the above composition.

(2) Preparation of Adhesive Composition 100 parts by mass of the (meth) acrylate copolymer (A) obtained in the above step (1) and trimethylolpropane-modified xylylenediene as an isocyanate-based crosslinking agent (B). 0.2 parts by mass of isocyanate (trade name “Takenate D110N” manufactured by Mitsui Chemicals, Inc.) and N-decylpyridinium bis (fluorosulfonyl) imide (ionic compound solid at room temperature) as an antistatic agent (C) 5 parts by mass, 0.2 parts by mass of 3-glycidoxypropyltrimethoxysilane (trade name "KBM403", manufactured by Shin-Etsu Chemical Co., Ltd.) as an epoxy group-containing silane coupling agent (D1), and a mercapto group-containing silane As a coupling agent (D2), a co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (Shin (X-41-1810, trade name, manufactured by Etsu Chemical Co., Ltd., mercapto equivalent: 450 g / mol), 0.2 parts by mass, sufficiently stirred, and diluted with ethyl acetate to obtain an adhesive composition. A coating solution of the product was obtained.

Here, each composition (solid content conversion value) of the adhesive composition when the (meth) acrylate copolymer (A) is 100 parts by mass (solid content conversion value) is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylate copolymer]
BA: n-butyl acrylate HEA: 2-hydroxyethyl acrylate IBXA: isobornyl acrylate PhEA: 2-phenylethyl acrylate CHA: cyclohexyl acrylate
[Isocyanate crosslinking agent]
XDI: trimethylolpropane-modified xylylene diisocyanate (trade name “Takenate D110N” manufactured by Mitsui Chemicals, Inc.)
HDI: Trimethylolpropane-modified hexamethylene diisocyanate (Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL")
[Antistatic agent]
Pry + FSI-: N-decylpyridinium bis (fluorosulfonyl) imide (ionic compound solid at room temperature)
K + PF6-: potassium hexafluorophosphate (ionic compound solid at room temperature)

(3) Preparation of Optical Film with Adhesive Layer A release sheet (SP-PET3811, manufactured by Lintec Co., Ltd., obtained by applying a coating solution of the obtained adhesive composition to one surface of a polyethylene terephthalate film with a silicone-based release agent) : 38 μm), and applied with a knife coater, followed by heat treatment at 90 ° C. for 1 minute to form a coating film of the adhesive composition.

  Next, the polarizing plate as the first optical film obtained above is bonded to the coating film so that the surface of the second protective layer and the exposed surface of the coating film are in contact with each other. After curing at 50% RH for 7 days, an optical film with a first pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer formed on a polarizing plate was obtained. Note that the thickness of the formed pressure-sensitive adhesive layer was 20 μm.

  Further, the composite polarizing plate as the second optical film obtained above, the above-mentioned, such that the surface of the first acrylic resin layer in the first retardation plate and the exposed surface of the coating film are in contact with each other. By laminating with a coating film and curing at 23 ° C. and 50% RH for 7 days, a second optical film with a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer formed on a composite polarizing plate was obtained. Note that the thickness of the formed pressure-sensitive adhesive layer was 20 μm.

[Examples 2 to 12, Comparative Examples 1 to 7]
The type and proportion of each monomer constituting the (meth) acrylate copolymer (A), the weight average molecular weight of the (meth) acrylate copolymer (A), and the type and blend of the isocyanate-based crosslinking agent (B) An optical film with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the amount, the type and the amount of the antistatic agent (C) were changed as shown in Table 1.

Here, the above-mentioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.
<Measurement conditions>
・ GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
-Measurement solvent: tetrahydrofuran-Measurement temperature: 40 ° C

  The following test examples were performed on the second optical film with a pressure-sensitive adhesive layer manufactured in the examples and the comparative examples.

[Test Example 1] (Measurement of gel fraction)
In place of the optical film used in the production of the optical film with the pressure-sensitive adhesive layer in the examples or comparative examples, a release sheet (SP-PET3801, manufactured by Lintec Co., Ltd., having one side of a polyethylene terephthalate film peeled off with a silicone release agent) (38 μm) to prepare an adhesive sheet. Specifically, the release sheet comes into contact with the release sheet on the exposed coating film of the release sheet / adhesive composition coating obtained in the production process of the example or the comparative example. And cured under conditions of 23 ° C. and 50% RH for 7 days. Thus, a pressure-sensitive adhesive sheet having a structure of release sheet (SP-PET3801) / pressure-sensitive adhesive layer (thickness: 20 μm) / release sheet (SP-PET3811) was produced.

  The obtained pressure-sensitive adhesive sheet is cut into a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer is wrapped in a polyester mesh (mesh size 200), the weight is weighed with a precision balance, and the weight of the mesh alone is subtracted. , The mass of only the pressure-sensitive adhesive was calculated. The mass at this time is defined as M1.

  Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C.) for 24 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in an environment at a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is defined as M2. The gel fraction (%) is represented by (M2 / M1) × 100. Table 2 shows the results.

[Test Example 2] (Evaluation of durability)
The optical film with the pressure-sensitive adhesive layer obtained in each of Examples and Comparative Examples was cut to prepare a sample having a size of 150 mm × 200 mm. After peeling off the release sheet from this sample and attaching it to non-alkali glass (Eagle XG, manufactured by Corning Incorporated) via the exposed pressure-sensitive adhesive layer, the autoclave manufactured by Kurihara Seisakusho was heated at 0.5 MPa and 50 ° C. for 20 minutes. Pressed.

Then, it was put in an environment under the following three durability conditions, and after 250 hours, the presence or absence of floating or peeling was confirmed using a 10-fold loupe. The evaluation criteria are as follows. Table 2 shows the results.
：: No lifting or peeling was observed.
：: Lifting or peeling of a size of 0.5 mm or less was confirmed.
Δ: Lifting or peeling of a size exceeding 0.5 mm and 1.0 mm or less was confirmed.
X: Floating or peeling of a size exceeding 1.0 mm was confirmed.
<Durability conditions>
・ Heat resistance: 85 ° C dry
・ Wet heat: 60 ° C, relative humidity 90% RH
・ H. S. : Heat shock test at -35 ℃ −70 ℃ for 30 minutes, 200 cycles

[Test Example 3] (Evaluation of warpage resistance)
The optical film with the pressure-sensitive adhesive layer obtained in each of Examples and Comparative Examples was cut so as to have a length of 200 mm and a width of 150 mm. The release sheet was peeled off from the optical film with the pressure-sensitive adhesive layer, and the exposed pressure-sensitive adhesive layer was placed at the center of non-alkali glass (commercial name: Eagle-XG) having a length of 250 mm, a width of 175 mm and a thickness of 0.5 mm. This was used as a sample. This sample was left at 85 ° C. in a dry atmosphere for 250 hours. Thereafter, the sample is taken out in an environment of 25 ° C. and 50% RH, placed on a horizontal table with the polarizing plate side up, and the amount of warpage from the table at each corner (4 points) (distance between the corner and the table) ) Was measured, and the amount of warpage of each corner was totaled. Based on the results, the warpage resistance was evaluated as follows. Table 2 shows the results.
：: Total warpage is 10 mm or less ○: Total warpage is more than 10 mm, 15 mm or less △: Total warpage is more than 15 mm, 20 mm or less ×: Total warpage is more than 20 mm

[Test Example 4] (Evaluation of heat unevenness)
The optical film with the pressure-sensitive adhesive layer obtained in each of the examples and the comparative examples was adjusted to a size of 200 mm × 150 mm using a cutting device (Ogino Seisakusho Co., Ltd., super cutter, PN1-600). After the release sheet was peeled off and pasted on an alkali-free glass (Eagle XG, manufactured by Corning Incorporated) via the exposed pressure-sensitive adhesive layer, pressure was applied at 0.5 MPa, 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. In addition, the said bonding was performed so that an optical film with an adhesive layer might be in a crossed Nicols state (polarization axis: 45 degrees, 135 degrees) on the front and back of non-alkali glass. In this state, it was left for 250 hours in an environment of 80 ° C. dry, and then left for 2 hours in an environment of 23 ° C. and 50% RH. Using this as a sample, the heat resistance unevenness was evaluated by the following method. Table 2 shows the results.

<Evaluation method>
The above sample was placed on a flat illuminator (HF-SL-A312LC, manufactured by Dentsu Sangyo Co., Ltd., illuminance: 26,000 Lux, luminance: 10,000 cd), and a two-dimensional color luminance meter (Konica Minolta, CA-2000) was used. ) And converted to a luminance distribution image by analysis software (Konica Minolta, CA-S20w). The luminance distribution image of the obtained sample was evaluated based on the evaluation criteria shown in FIG. 4 and the following.
A: The luminance distribution is almost uniform.
：: There is some distortion in the luminance distribution on the four sides.
Δ: There is a clear distortion in the luminance distribution on the four sides.
X: There is severe distortion in the luminance distribution on the four sides.

[Test Example 5] (Evaluation of corrosion resistance)
<Preparation of metal film laminated glass substrate>
A metal aluminum layer having a thickness of 500 nm was formed on one surface of a previously prepared alkali-free glass by a sputtering method using aluminum as a sputtering target and argon as a sputtering gas.

  Next, a methacrylic acid derivative containing phosphoric acid groups (Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) was added to an acrylic hard coat agent (Opster (registered trademark) Z7535, manufactured by JSR) at 2% by mass in terms of solid content. The resulting mixture was diluted with methyl ethyl ketone as a diluting solvent to a solid content of 7.5% by mass to obtain a coating solution of a hard coat agent.

The coating liquid of the obtained hard coat agent is applied to the exposed surface side of the metal aluminum layer, dried at 80 ° C. for 3 minutes, and irradiated with ultraviolet rays (using a mercury lamp, 1200 mJ / cm ² ) to apply the coating liquid. By cross-linking the film, a surface hard coat layer having a thickness of 2.0 μm was formed. As a result, a metal film laminated glass substrate in which a metal aluminum layer and a surface hard coat layer were sequentially formed on one surface of the glass substrate was produced.

<Evaluation of corrosion resistance>
The optical films with an adhesive layer obtained in Examples and Comparative Examples were cut into test pieces having a size of 20 mm x 50 mm. The release sheet was peeled from the test piece, and the exposed pressure-sensitive adhesive layer was attached to the exposed surface side of the surface hard coat layer of the metal film-laminated glass substrate obtained in the above step. This was stored in an oven at a temperature of 60 ° C. and a relative humidity of 90% for 750 hours, and then taken out at room temperature. Then, the state of the metal aluminum layer in the portion where the test piece was bonded to the metal film laminated glass substrate was observed, and the corrosion resistance was evaluated based on the following criteria. Table 2 shows the results.
〇: No pitting or clouding occurred in the metallic aluminum layer.
X: Pitting corrosion or cloudiness has occurred in the metal aluminum layer.

[Test Example 6] (Measurement of surface resistivity of pressure-sensitive adhesive layer)
The optical films with an adhesive layer obtained in Examples and Comparative Examples were cut into a size of 50 mm × 50 mm, and the obtained samples were left at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours. Thereafter, the release sheet was peeled off, and the exposed pressure-sensitive adhesive layer surface was subjected to a surface resistivity (Ω / sq) according to JIS K6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Hiresta UP MCP-HT450 type). ) Was measured. Table 2 shows the results.

[Test Example 7] (Measurement of adhesive strength-Evaluation of reworkability)
A sample having a width of 25 mm and a length of 100 mm was cut out from the optical film with a pressure-sensitive adhesive layer obtained in each of Examples and Comparative Examples, the release sheet was peeled off, and an alkali-free glass (manufactured by Corning Incorporated, Eagle Corp.) was passed through the exposed pressure-sensitive adhesive layer. XG), and then pressurized in an autoclave manufactured by Kurihara Seisakusho at 0.5 MPa and 50 ° C. for 20 minutes. Then, after leaving for 24 hours under the condition of 23 ° C. and 50% RH, the adhesive force (sticking) was performed using a tensile tester (manufactured by Orientec, Tensilon) at a peeling speed of 300 mm / min and a peeling angle of 180 °. One day later, the adhesive strength; N / 25 mm) was measured. The conditions other than those described here were measured in accordance with JIS Z 0237: 2009. Table 2 shows the results.

  Furthermore, after leaving it to stand at 23 ° C. and 50% RH for 14 days, the adhesive strength (the adhesive strength 14 days after application; N / 25 mm) was measured in the same manner as above. Table 2 shows the results.

Based on the adhesive strength 14 days after the application, the reworkability was evaluated according to the following criteria. Table 2 shows the results.
◎: Adhesive strength 14 days after application is 8.8 N / 25 mm or less ：: Adhesive strength 14 days after application is more than 8.8 N / 25 mm and less than 10 N / 25 mm △: Adhesive strength 14 days after application is 10 N / 25 mm or more, 20 N / Less than 25 mm ×: Adhesive strength 14 days after application is 20 N / 25 mm or more

[Test Example 8] (Measurement of haze value)
As in Test Example 1, the configuration of a release sheet (SP-PET3801) / pressure-sensitive adhesive layer (thickness: 20 μm) / release sheet (SP-PET3811) having a pressure-sensitive adhesive layer corresponding to each example or each comparative example. Was prepared (cured for 7 days). Using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH2000), a haze value (%) (may be abbreviated as Hz (%)) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to JIS K7136: 2000. It was measured. Table 2 shows the results.

  As can be seen from Table 2, the optical film with the pressure-sensitive adhesive layer obtained in the example was excellent in durability, hardly warped even at a high temperature, and hardly caused heat unevenness. In addition, the optical film with the pressure-sensitive adhesive layer obtained in the example was excellent in corrosion resistance to the transparent conductive film, and had a low surface resistivity of the pressure-sensitive adhesive layer and exhibited good antistatic properties. Furthermore, the optical film with a pressure-sensitive adhesive layer obtained in the example was excellent in reworkability, and the pressure-sensitive adhesive layer in the example had high transparency.

  The pressure-sensitive adhesive, the pressure-sensitive adhesive sheet and the optical film with a pressure-sensitive adhesive layer according to the present invention are suitable for bonding a polarizing plate or a composite polarizing plate to a liquid crystal cell, particularly a liquid crystal cell having a transparent conductive film on a bonding surface. is there.

10A, 10B ... Optical film with adhesive layer 1 ... Adhesive layer 2A ... Polarizing plate 2B ... Composite polarizing plate 21 ... Polarizer 22 ... First protective layer 23 ... Second protective layer 24 ... First retardation plate 241, a first acrylic resin layer 242, a retardation expression layer 243, a second acrylic resin layer 25, a second retardation plate 26, a second adhesive layer 27, a protective layer

Claims (11)

The monomer unit constituting the polymer contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3), and has a hydroxyl value of 5 to 20 mgKOH / g. A (meth) acrylate copolymer (A) having a value of 2 mgKOH / g or less and a weight average molecular weight of 1.3 to 3,000,000,
An isocyanate-based crosslinking agent (B);
An adhesive obtained from an adhesive composition containing an antistatic agent (C),
The gel fraction of the pressure-sensitive adhesive is 62 to 90%,
The antistatic agent (C) is, Ri ionic compound der containing fluorosulfonyl imide as an anion,
A pressure-sensitive adhesive characterized in that an object to be stuck is a transparent conductive film .   The pressure-sensitive adhesive according to claim 1, wherein the alicyclic structure in the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure.   The pressure-sensitive adhesive according to claim 1, wherein the pressure-sensitive adhesive composition further contains an epoxy group-containing silane coupling agent (D1).   The pressure-sensitive adhesive according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive composition further contains a mercapto group-containing silane coupling agent (D2).   The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the isocyanate-based crosslinking agent (B) is a compound having an aromatic ring. The pressure-sensitive adhesive according to any one of claims 1 to 5, wherein the antistatic agent (C) is an ionic compound containing a nitrogen-containing heterocyclic cation as a cation. The said (meth) acrylic-ester copolymer (A) contains 1-20 mass% of the said alicyclic structure containing monomer (a1) as a monomer unit which comprises the said polymer. The pressure-sensitive adhesive according to any one of claims 1 to 6. The said (meth) acrylic-ester copolymer (A) contains the said aromatic ring-containing monomer (a2) as 1-30 mass% as a monomer unit which comprises the said polymer. 8. The pressure-sensitive adhesive according to claim 7. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to any one of claims 1 to 8 . An optical film,
An optical film with a pressure-sensitive adhesive layer, comprising: a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to any one of claims 1 to 8 , which is laminated on at least one surface of the optical film. An optical film,
An adhesive layer made of the adhesive according to any one of claims 1 to 8, which is laminated on at least one surface of the optical film,
A transparent conductive film laminated on the side opposite to the optical film side in the adhesive layer.
A laminate comprising:

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