TW201636655A - Polarizing plate with adhesive layer - Google Patents

Abstract

The present invention provides a polarizing plate with an adhesive layer, which is characterized in providing excellent durability to a display panel that is hard to warp and hard to generate uneven heat, even if the polarizing plate is a thin film. Disclosed is a polarizing plate (10A) with an adhesive layer, comprising: a photon (21); a first protective layer (22) laminated on one side of the photon (21); a second protective layer (23) laminated on the other side of the photon (21); and an adhesive layer (1) laminated on one side of the second protective layer (23), which is opposite to the side laminated with the photon (21). In the polarizing plate (10A) with the adhesive layer, the adhesive layer (1) is composed of an adhesive with its gel fraction of 60~89% obtained from an adhesive composition. The above adhesive composition is composed of: a (metha)crylate copolymer (A) containing an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2) and a hydroxyl-containing monomer (a3) as a monomer unit for composing a polymer, with a hydroxyl value of 5~20mgKOH/g, acid value less than 5mgKOH/g and weight-average molecular weight of 1,300,000~3,000,000; and a melamine-based crosslinking agent (B). The second protective layer (23) is composed of a cyclic olefin-based resin or triacetin fiber. The thickness of the photon (21) is 1~20[mu]m. The thickness of the second protective layer (23) is 5~30[mu]m. The thickness value of the second protective layer (23) as compared to the thickness of the photon (21) is 1.0~5.0.

Description

Polarizing plate with adhesive layer

The present invention relates to a polarizing plate with an adhesive layer attached thereto.

In recent years, as a display panel of various electronic devices, a touch panel that doubles as a display device and an input mechanism has been widely used. The types of touch panels are mainly resistive film type, capacitive type, optical type and ultrasonic type, resistive film type has analog film type and matrix resistive film type; capacitive type has surface type and projection type.

Projection type capacitors are widely used in touch panels of mobile electronic devices such as smart phones or tablets that have recently attracted attention. As a projection type capacitive touch panel of a related mobile electronic device, for example, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, and a transparent layer are laminated in this order. Protective sheet for conductive film (ITO) and tempered glass.

As the optical component constituting the above liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell is usually disposed such that an alignment layer of two transparent electrode substrates forming an alignment layer is formed inside, and a spacer is formed at a predetermined interval, and a liquid crystal material is sandwiched between the two transparent electrode substrates. Usually, the outer side of the two transparent electrode substrates in the liquid crystal cell is respectively adhered to the polarizing plate by an adhesive.

As an adhesive for optical use, for example, Patent Document 1 is known. By. The adhesive contains a (meth)acrylic polymer, and contains 0.02 to 2 parts by mass of a peroxide as a crosslinking agent and 100% of an epoxy crosslinking agent with respect to 100 parts by mass of the (meth)acrylic polymer. 5 parts by mass, the (meth)acrylic polymer is a monomer unit, and contains a carboxyl group-containing monomer with respect to 100 parts by mass of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms. 0.2 to 20 parts by mass is composed as a copolymerization component.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2009-242786

Here, with the demand for thinning of mobile electronic devices in recent years, thinning is also required for polarizing plates. However, the polarizing plate of the film has a high shrinkage rate due to heat or the like, and in the conventional adhesive such as Patent Document 1, there is a concern that the display panel is warped or that it is lifted or surfaced under high temperature conditions or under moist heat conditions. Peeling and other issues. Further, in order to improve the durability of the adhesive, when a monomer having a high glass transition point (Tg) is copolymerized as a constituent component of a (meth)acrylic polymer, a large shrinkage stress is generated under high temperature conditions. The warpage of the display panel increases. It is also pointed out that due to the stress at the time of thermal contraction of the polarizing plate, there is a problem of light leakage (so-called heat unevenness) caused by the deviation of the optical axis of the polarizing plate.

The present invention has been made in view of such an actual situation, and an object thereof is to provide a polarizing layer with an adhesive layer which is excellent in durability, a display panel is not easily warped, and is not easily thermally uneven even when a polarizing plate is a film. board.

In order to achieve the above object, the present invention provides a polarizing plate with an adhesive layer, comprising: a polarizer; a first protective layer laminated on one surface side of the polarizer; and a layer deposited on the other side of the polarizer a second protective layer; and an adhesive layer laminated on a side of the second protective layer opposite to the surface on the polarizer side; in the polarizing plate with the adhesive layer, the adhesive layer is composed of adhesive The adhesive composition comprising a gel fraction of 60 to 89%, the adhesive composition comprising: (meth) acrylate copolymer (A) containing an alicyclic structure-containing monomer (a1), containing a fragrance The ring monomer (a2) and the hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer have a hydroxyl value of 5 to 20 mgKOH/g, an acid value of 5 mgKOH/g or less, and a weight average molecular weight of 1.3 to 3,000,000; And the isocyanate type crosslinking agent (B), wherein the second protective layer is composed of a cycloolefin resin or triacetyl cellulose, the polarizer has a thickness of 1 to 20 μm, and the second protective layer has a thickness of 5 to 30 μm. The ratio of the thickness of the second protective layer to the thickness of the polarizer is 1.0 to 5.0 ( Ming 1).

According to the polarizing plate with the adhesive layer attached to the invention (Invention 1), the polarizing plate has been thinned compared with the conventional product. However, when the polarizing plate with the adhesive layer is applied to a display panel, the polarizing plate with the adhesive layer is excellent in durability, and the display panel is less likely to warp and is less likely to cause thermal unevenness.

In the above invention (Invention 1), the thickness of the first protective layer is 5 to 120 μm, and the ratio of the thickness of the first protective layer to the thickness of the polarizer is preferably 1.0 to 6.0 (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferred that the first protective layer is made of triacetyl cellulose (Invention 3).

In the above invention (Inventions 1 to 3), the alicyclic structure of the alicyclic structure-containing monomer (a1) is preferably a polycyclic alicyclic structure (Invention 4).

In the above invention (Inventions 1 to 4), it is preferred that the adhesive composition further contains an epoxy group-containing decane coupling agent (C1) (Invention 5).

In the above invention (Inventions 1 to 5), it is preferred that the adhesive composition further contains a mercaptodecane-containing coupling agent (2) (Invention 6).

In the above invention (Inventions 1 to 6), it is preferred that the adhesive composition further contains an antistatic agent (D) (Invention 7).

In the above invention (Invention 7), the antistatic agent (D) is preferably an ionic compound which is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion (Invention 8).

In the above invention (Inventions 1 to 8), the isocyanate crosslinking agent (B) is preferably a compound having an aromatic ring (Invention 9).

In the above invention (Inventions 1 to 9), it is preferred that the (meth) acrylate copolymer (A) contains no carboxyl group-containing monomer as a monomer unit constituting the polymer (Invention 10).

In the above invention (Inventions 1 to 10), the (meth) acrylate copolymer (A) contains the alicyclic structure-containing monomer (a1) containing 1 to 40% by mass as a monomer constituting the polymer. The unit is preferred (Invention 11).

In the above invention (Inventions 1 to 11), the (meth) acrylate copolymer (A) contains the aromatic ring-containing monomer (a2) in an amount of 1 to 40% by mass as a monomer unit constituting the polymer. Preferably (Invention 12).

In the above invention (Inventions 1 to 12), the (meth) acrylate copolymer (A) contains 0.5 to 10% by mass of the hydroxyl group-containing monomer (a3). The monomer unit constituting the polymer is preferred (Invention 13).

In the above invention (Inventions 1 to 13), it is preferred that the surface resistivity of the pressure-sensitive adhesive layer is 1.0 × 10 ¹² Ω/sq or less (Invention 14).

According to the polarizing plate with an adhesive layer of the present invention, even when the polarizing plate is a film, the durability is excellent, the display panel is less likely to warp, and heat unevenness is less likely to occur.

10A, 10B‧‧‧ polarizer with adhesive layer

1‧‧‧Adhesive layer

2A‧‧‧Polar plate

2B‧‧‧Composite polarizer

21‧‧‧Polar photons

22‧‧‧1st protective layer

23‧‧‧2nd protective layer

24‧‧‧1st phase difference plate

241‧‧‧1st acrylic resin layer

242‧‧‧ phase difference performance layer

243‧‧‧2nd acrylic resin layer

25‧‧‧2nd phase difference plate (2nd protective layer)

26‧‧‧2nd adhesive layer

27‧‧‧Protective layer (1st protective layer)

Fig. 1 is a cross-sectional view showing a polarizing plate with an adhesive layer according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a polarizing plate with an adhesive layer according to a second embodiment of the present invention.

3 is a cross-sectional view showing a configuration example of a phase difference plate.

Fig. 4 is a view (color) showing the evaluation criteria of the heat resistance unevenness test (visual observation) of the polarizing plate with the adhesive layer.

Hereinafter, embodiments of the present invention will be described.

[First Embodiment]

As shown in Fig. 1, the polarizing plate 10A with an adhesive layer according to the first embodiment of the present invention is configured to include a polarizer 21 and a first protective layer laminated on one surface side (upper side in Fig. 1) of the polarizer 21. a layer 22; a second protective layer 23 laminated on the other surface side of the polarizer 21 (lower side in FIG. 1); and a layer side opposite to the surface of the second protective layer 23 on the side of the polarizer 21 (Fig. 1 is the lower side) Adhesive layer 1. In the present embodiment, the laminated body of the first protective layer 22, the polarizer 21, and the second protective layer 23 constitutes the polarizing plate 2A. Further, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the side of the polarizing plate 2A until the polarizing plate 10A having the adhesive layer is used.

The pressure-sensitive adhesive layer 1 is composed of an adhesive which is obtained from an adhesive composition (hereinafter sometimes referred to as "adhesive composition P") and has a gel fraction of 60 to 89%. The adhesive composition contains: The (meth) acrylate copolymer (A) contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, and a hydroxyl value. It is 5 to 20 mgKOH/g, an acid value of 5 mgKOH/g or less, a weight average molecular weight of 1.3 million to 3,000,000, and an isocyanate crosslinking agent (B). Further, in the present specification, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same.

Further, the second protective layer 23 is made of a cycloolefin resin or triacetyl cellulose, the thickness of the polarizer 21 is 1 to 20 μm, the thickness of the second protective layer 23 is 5 to 30 μm, and the thickness of the second protective layer 23 is The ratio with respect to the thickness of the polarizer 2 is 1.0 to 5.0.

In the polarizing plate 10A with the adhesive layer which satisfies the above requirements, the polarizing plate 2A is thinned compared with the conventional product, and the display panel can be made thinner. However, when the polarizing plate 10A with the adhesive layer is applied to the display panel, the polarizing plate 10A with the adhesive layer is excellent in durability, under high temperature conditions, under moist heat conditions or under thermal shock. Suppresses the occurrence of lift or surface peeling. Further, the display panel using the above-described polarizing plate 10A with an adhesive layer is not easily warped under high temperature conditions, and heat unevenness is less likely to occur.

Adhesive layer

(1) Physical properties

As described above, the (meth) acrylate copolymer (A) contained in the adhesive composition P constituting the adhesive layer 1 of the present embodiment has a hydroxyl value of 5 to 20 mgKOH/g and an acid value of 5 mgKOH. Below /g, the weight average molecular weight is 1.3 million to 3 million. Further, the adhesive obtained from the adhesive composition P had a gel fraction of 60 to 89%.

When the hydroxyl value of the (meth) acrylate copolymer (A) is less than 5 mgKOH/g, the crosslinking point is too small and the cohesive force is lowered, and the obtained adhesive does not exhibit excellent durability. In addition, when the hydroxyl value of the (meth) acrylate copolymer (A) exceeds 20 mg KOH/g, the crosslinking point is too large, the obtained adhesive becomes soft, and the stress relaxation property is lowered, thereby being under high temperature conditions. The display panel is warped or thermally uneven.

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

On the other hand, when the acid value of the (meth) acrylate copolymer (A) is 5 mgKOH/g or less, even if the adhesion of the adhesive is caused by an acid, for example, tin-doped indium oxide (for example, tin-doped indium oxide) When a transparent conductive film such as ITO) or a metal film or the like is used, it is possible to suppress such a problem due to the occurrence of acid. In particular, when the attached object is a transparent conductive film, corrosion of the transparent conductive film or a change in resistance value of the transparent conductive film can be suppressed.

From the above point of view, (meth) acrylate copolymer (A) The upper limit of the acid value is preferably 2 mgKOH/g or less, and more preferably 1 mgKOH/g or less. In addition, the lower limit of the acid value of the (meth) acrylate copolymer (A) is preferably as small as possible, and particularly preferably 0 mgKOH/g.

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

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 layer 1 of the present embodiment is deteriorated. In addition, when the weight average molecular weight of the (meth) acrylate copolymer (A) exceeds 3,000,000, the stress relaxation property of the adhesive layer 1 of the present embodiment is lowered, and the display panel is warped or thermally generated under high temperature conditions. Uneven.

From the above viewpoints, the lower limit of the weight average molecular weight of the (meth) acrylate copolymer (A) is preferably 1.5 million or more, and more preferably 1.6 million or more. Further, 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 1.9,000,000 or less.

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

Further, when the gel fraction of the adhesive constituting the adhesive layer 1 is less than 60%, the durability of the adhesive is deteriorated. On the other hand, when the gel fraction of the adhesive constituting the adhesive layer 1 exceeds 89%, the stress relaxation property of the adhesive layer 1 is lowered, and the display panel is warped or thermally uneven under high temperature conditions.

From the above viewpoints, the lower limit of the gel fraction of the adhesive constituting the adhesive layer 1 is preferably 65% or more, and more preferably 70% or more. Further, the upper limit of the gel fraction of the adhesive constituting the adhesive layer 1 is 85% or less. Good, 78% or less is especially good. Moreover, the measuring method of the gel fraction of an adhesive is shown by the test example mentioned later.

The haze value (value measured in accordance with JIS K7136:2000) of the pressure-sensitive adhesive layer 1 in the present embodiment is preferably 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 as an optical user.

(2) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) in the present embodiment contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3) as constituent polymers. Monomer unit. Among the monomers, in particular, by containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2), the obtained adhesive can have both appropriate cohesive force and stress relaxation property, and Since the adhesion between the polarizing plate and the transparent conductive film is improved, when used in a display panel, excellent durability, warpage suppression, and heat unevenness can be exhibited.

The (meth) acrylate copolymer (A) contains, in addition to the above-mentioned alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3), and further contains an alkyl group. The alkyl (meth)acrylate having 1 to 20 carbon atoms is preferred as the monomer unit constituting the polymer. In addition, other monomers may be contained as needed.

The (meth) acrylate copolymer (A) contains an alkyl (meth) acrylate having 1 to 20 carbon atoms as an alkyl group constituting the polymer, whereby a good adhesion can be exhibited. . Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. N-butyl methacrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, (methyl) 2-ethylhexyl acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, ( Cetylmethyl methacrylate, octadecyl (meth) acrylate, and the like. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferred, n-butyl (meth)acrylate or 2-ethyl (meth)acrylate. The hexyl hexyl ester is particularly preferred. Further, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A) is preferably an alkyl (meth) acrylate having 1 to 20 carbon atoms and having 40 to 97.5% by mass of an alkyl group as a monomer unit constituting the polymer. It is particularly preferably contained in an amount of 55 to 94% by mass, and more preferably 65 to 83% by mass. When 40% by mass or more of the alkyl (meth)acrylate is contained, the (meth)acrylate copolymer (A) can be provided with an appropriate adhesiveness. In addition, by setting the alkyl (meth)acrylate to 97.5% by mass or less, it is possible to introduce a desired amount of other monomer components into the (meth) acrylate copolymer (A).

The carbon ring of the alicyclic structure in the alicyclic structural monomer (a1) may be a saturated structure or a partially unsaturated bond. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. 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 property to the adhesive. (Multi-ring structure) is preferred. Further considering the compatibility of the (meth) acrylate copolymer (A) with other components, the above polycyclic structure is particularly preferably bicyclic to tetracyclic. Further, from the viewpoint of imparting stress relaxation in the same manner as described above, the number of carbon atoms of the alicyclic structure (It means that the number of all carbon atoms in the portion forming the ring, and when a plurality of rings are present independently, the total number of carbon atoms is usually 5 or more is preferable, and 7 or more is particularly preferable. On the other hand, the upper limit of the number of carbon atoms of the alicyclic structure is not particularly limited. However, similarly to the above, from the viewpoint of compatibility, 15 or less is preferable, and 10 or less is particularly preferable.

Examples of the alicyclic structure include those having a skeleton, a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isobornyl skeleton, a cycloalkane skeleton (cycloheptane skeleton, a cyclooctane skeleton, and a ring). a decane skeleton, a cyclodecane skeleton, a cycloundecyl skeleton, a cyclododecane skeleton, etc.), a cycloolefin skeleton (a cycloheptene skeleton, a cyclooctene skeleton, etc.), a norbornene skeleton, a norbornadiene skeleton, a cubane skeleton, a snail skeleton, an alkane skeleton, a spiro skeleton, or the like, which contains a dicyclopentadiene skeleton (an alicyclic structure having 10 carbon atoms: 10) and an adamantane skeleton capable of exhibiting more excellent durability. (the number of carbon atoms of the alicyclic structure: 10) or the isobornyl skeleton (the number of carbon atoms of the alicyclic structure: 7) is preferred, and particularly preferably the one comprising the isobornyl skeleton.

As the alicyclic structure-containing monomer (a1), a (meth) acrylate monomer having the above skeleton is preferable, and specific examples thereof include cyclohexyl (meth) acrylate and (meth) acrylate. Dicyclopentyl ester, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. It is preferable to use dicyclopentyl (meth)acrylate, amantadine (meth)acrylate or isobornyl (meth)acrylate, which is excellent in durability, and particularly preferably isobornyl (meth)acrylate. Ester, these may be used singly or in combination of two or more.

Excellent durability and warpage suppression from the obtained adhesive The (meth) acrylate copolymer (A) contains, as a monomer unit constituting the polymer, an alicyclic structure-containing monomer (a1) containing 1 to 40% by mass as a viewpoint of heat resistance and non-uniformity. Preferably, it is more preferably 2 to 30% by mass, and particularly preferably 3 to 20% by mass. In addition to the above viewpoints, from the viewpoint of exhibiting excellent reprocessability of the obtained adhesive, it is particularly preferable to contain the alicyclic structure-containing monomer (a1) in an amount of 2 to 15% by mass, and contains 3~ 9% by mass is particularly good.

As the aromatic ring-containing monomer (a2), a (meth) acrylate having an aromatic ring is preferred. The aromatic ring may, for example, be a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring or an anthracene ring, and a benzene ring is preferred.

Examples of the aromatic ring-containing monomer (a2) include phenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, benzyl (meth)acrylate, and naphthyl (meth)acrylate. Phenyloxyethyl (meth)acrylate, phenoxybutyl (meth)acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth) acrylate, epoxy B Alkyl modified cresol (meth) acrylate, ethylene oxide (EO) modified nonyl phenol (meth) acrylate, etc., wherein 2-benzyl (meth) acrylate is used from the viewpoint of improving cohesion A phenyl group is preferred. These may be used singly or in combination of two or more.

The (meth) acrylate copolymer (A) is preferably a monomer unit containing the aromatic ring-containing monomer (a2) in an amount of 1 to 40% by mass, preferably 2 to 30% by mass, more preferably 2 to 30% by mass. It is particularly preferably contained in an amount of from 3 to 25% by mass, and more preferably from 12 to 22% by mass. By setting the content of the aromatic ring-containing monomer (a2) within the above range, the obtained adhesive can exhibit excellent durability, warpage inhibition property, and heat unevenness.

(Meth)acrylate 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 crosslinking agent (B), and the (meth) acrylate copolymer (A) is crosslinked by the isocyanate crosslinking agent (B) by the reaction thereof. Due to this crosslinked structure, the obtained adhesive is excellent in durability.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (methyl). a hydroxyalkyl (meth) acrylate such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, wherein the isocyanate crosslinking agent (B) From the viewpoint of reactivity, 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is particularly preferred. These may be used singly or in combination of two or more.

The (meth) acrylate copolymer (A) preferably contains 0.5 to 10% by mass of the hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, more preferably 1 to 5% by mass, further It is preferably contained in an amount of 2 to 4% by mass. By setting the content of the hydroxyl group-containing monomer (a3) within the above range, the hydroxyl value of the (meth) acrylate copolymer (A) can be easily dropped within the above range, and excellent durability can be effectively exhibited. Warpage inhibition and heat unevenness.

In order to make the acid value within the above range, it is preferred that the (meth) acrylate copolymer (A) contains no carboxyl group-containing monomer as a monomer unit constituting the polymer, and even if it contains a carboxyl group-containing monomer, it contains The content of 0.5% by mass or less is preferably, and particularly preferably 0.1% by mass or less.

The (meth) acrylate copolymer (A) may contain a monomer other than the above monomers as a monomer unit constituting the polymer. In order not to hinder The reaction between the hydroxyl group of the hydroxyl group-containing monomer (a3) and the isocyanate crosslinking agent (B), and the monomer which does not contain a functional group reactive with the isocyanate crosslinking agent (B) is used as the other monomer. good.

Examples of the other monomer include a (meth)acrylic acid alkoxyalkyl ester such as methoxyethyl (meth)acrylate or ethoxyethyl (meth)acrylate; acrylamide; Non-crosslinkable acrylamide such as acrylamide; N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. A crosslinkable tertiary amino group (meth) acrylate; vinyl acetate or the like. These may be used singly or in combination of two or more.

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

Here, in the adhesive composition P, the (meth) acrylate copolymer (A) may be used alone or in combination of two or more. Further, the adhesive composition P may further contain a (meth) acrylate polymer in which the (meth) acrylate polymer does not contain an alicyclic structure-containing monomer (a1) or an aromatic ring-containing monomer ( A2) or a hydroxyl group-containing monomer (a3) as a constituent monomer unit.

(3) Isocyanate crosslinking agent (B)

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

The isocyanate crosslinking agent (B) is a compound containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isofluoride. In addition to alicyclic polyisocyanates such as ketone diisocyanate and hydrogenated diphenylmethane diisocyanate, there are also such biuret bodies, isocyanurate bodies, and further ethylene glycol and propylene glycol. An adduct of a reactant containing a low molecular weight active hydrogen compound such as neopentyl glycol, trimethylolpropane or castor oil (hereinafter referred to collectively as "modified body"). Among these, from the viewpoint of the durability of the obtained adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified form thereof is preferred, and has an organic group (for example, A polyisocyanate which is preferably an alkylene chain, particularly preferably an alkylene chain having 1 to 4 carbon atoms and an isocyanate group bonded to an aromatic ring, or a modified form thereof is particularly preferred. Specifically, xylylene diisocyanate or a modified form thereof is further preferred, and trimethylolpropane modified xylylene diisocyanate is preferred. These isocyanate type crosslinking agents (B) may be used alone or in combination of two or more.

The content of the isocyanate crosslinking agent (B) in the adhesive composition P is preferably 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A). Particularly preferably, 0.1 to 0.4 parts by mass is further preferred. When the content of the isocyanate-based crosslinking agent (B) is within the above range, the gel fraction of the adhesive tends to fall within the above range, and durability, warpage inhibition, and heat unevenness can be easily obtained. Adhesive.

(4) decane coupling agent (C)

In addition to the above (meth) acrylate copolymer (A) and the isocyanate crosslinking agent (B), the adhesive composition P preferably contains a decane coupling agent (C), and the adhesion obtained from the adhesion is obtained. From the viewpoint of excellent durability of the agent, it is particularly preferred to contain an epoxy group-containing decane coupling agent (C1) and/or a decyl decane coupling agent (C2), and further preferably an epoxy group-containing decane coupling agent (C1). ) and Both of the decyl decane coupling agents (C2).

As an epoxy group-containing decane coupling agent (C1), an organic ruthenium compound having at least one epoxy group (epoxy group-containing organic group) and at least one alkoxy decyl group in the molecule, and an adhesive component Those with good compatibility and light transmissivity, for example, are substantially transparent.

Specific examples of the epoxy group-containing decane coupling agent (C1) include 3-glycidol such as 3-glycidoxypropyltrimethoxydecane or 3-glycidoxypropyltriethoxysilane. Oxypropylpropylalkoxydecane; 3-glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropylmethyldimethoxydecane, etc. 3-glycidoxypropyl Alkyl dialkoxy decane; methyl tris(glycidyl) decane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 2-(3,4-epoxycyclohexyl 2-(3,4-epoxycyclohexyl)ethyltrialkoxydecane, etc., such as ethyltriethoxydecane. Among them, from the viewpoint of further improving durability, 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, 3-glycidoxypropylmethyldi Ethoxy decane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxynonane is preferred, and 3-glycidoxypropyltrimethoxydecane is particularly preferred. These may be used alone or in combination of two or more.

Suitable as a mercapto-containing decane coupling agent (C2), an organic antimony compound having at least one mercapto group (an organic group containing a mercapto group) and at least one alkoxyalkyl group in the molecule, and having good compatibility with an adhesive component and Those having light transmissivity, for example, are substantially transparent.

Specific examples of the mercapto-containing decane coupling agent (C2) include 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, and 3-decyl group. a fluorenyl-containing low molecular type decane coupling agent such as propyldimethoxymethyl decane; and a decyl decane-containing compound (for example, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 3-mercaptoyl) Propyl dimethoxymethyl decane, etc.) and alkyl-containing decane compounds (for example, methyl triethoxy decane, ethyl triethoxy decane, methyl trimethoxy decane, ethyl trimethoxy decane, etc.) A mercapto group-containing oligomer-type decane coupling agent or the like. Among them, a fluorenyl group-containing oligomer-type decane coupling agent is preferred from the viewpoint of achieving both durability and reworkability, and particularly preferably a cocondensate of a decyl decane compound and an alkyl decane-containing compound, further preferably a cocondensate of 3-mercaptopropyltrimethoxydecane with methyltriethoxydecane. These may be used alone or in combination of two or more.

As the decane coupling agent (C), in addition to the above-mentioned epoxy group-containing decane coupling agent (C1) and a mercapto-containing decane coupling agent (C2), for example, an acrylonitrile-based decane coupling agent or a hydroxy-based decane coupling may be used as needed. A mixture, a carboxy-based decane coupling agent, an amine-based decane coupling agent, a guanamine-based decane coupling agent, an isocyanate-based decane coupling agent, and the like.

The total content of the decane coupling agent (C) in the adhesive composition P is preferably 0.01 to 5 parts by mass, particularly preferably 0.1 to 2 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). Further, it is preferably 0.2 to 1 part by mass.

In addition, the content of the epoxy group-containing decane coupling agent (C1) in the adhesive composition P is preferably 0.005 to 2.5 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A), particularly preferably It is 0.05 to 1 part by mass, and more preferably 0.1 to 0.5 part by mass. On the other hand, the content of the mercapto-containing decane coupling agent (C2) in the adhesive composition P is relative to the (meth) acrylate copolymer. (A) 100 parts by mass, preferably 0.005 to 2.5 parts by mass, particularly preferably 0.05 to 1 part by mass, still more preferably 0.1 to 0.5 part by mass.

(5) Antistatic agent (D)

The adhesive composition P further preferably contains an antistatic agent (D). The release sheet laminated on the adhesive layer 1 or the polarizing plate is usually made of a plastic material, and therefore has high electrical insulation, such as static electricity easily generated when the release sheet is peeled off. When the polarizing plate is bonded to the liquid crystal cell in a state where the static electricity generated in this manner remains, the alignment of the liquid crystal molecules may be disturbed, and the presence of static electricity may cause problems such as the attraction of flying dust or dust. Therefore, since the adhesive composition P contains the antistatic agent (D), the obtained adhesive (adhesive layer 1) can exhibit antistatic properties, thereby eliminating the above problems.

The antistatic agent (D) is not particularly limited as long as it can provide the antistatic property of the obtained adhesive, and examples thereof include an ionic compound and a nonionic compound. Among them, an ionic compound is preferred. The ionic compound may be a liquid or a solid at room temperature, but is preferably solid at room temperature from the viewpoint of easily exhibiting stable antistatic properties even when exposed to endurance conditions. Here, the ionic compound in the present specification means a compound mainly composed of a cation and an anion and bonded by electrostatic attraction.

As the ionic compound, a nitrogen-containing phosphonium salt, a sulfur-containing phosphonium salt, a phosphorus-containing phosphonium salt, an alkali metal salt, and an alkaline earth metal salt are preferable, and from the viewpoint of excellent durability of the obtained adhesive, it is particularly preferable. Nitrogen-containing barium salt. The nitrogen-containing phosphonium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a counter anion thereof, particularly preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion, and more preferably at room temperature. The lower is a solid and is halogenated by a nitrogen-containing heterocyclic cation. An ionic compound composed of a phosphate anion. According to the ionic compound which is solid at room temperature and consists of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion, both antistatic property and durability can be achieved.

As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, an anthracene ring or the like is preferable, and a pyridine ring is preferred. Further, as the halogen of the halogenated phosphoric acid anion, fluorine, chlorine, bromine or the like is preferable, and among them, fluorine is preferred.

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, and N-octyl group. Pyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N - cetylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4-methylpyridinium hexafluorophosphate, N- Cetyl-4-methylpyridinium hexafluorophosphate and the like. Among these, from the viewpoint of compatibility with the (meth) acrylate copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methyl Pyridinium hexafluorophosphate and N-octyl-4-methylpyridinium hexafluorophosphate are preferred. The above antistatic agents (D) may be used alone or in combination of two or more.

The content of the antistatic agent (D) in the adhesive composition P is preferably 0.1 to 15 parts by mass, particularly preferably 0.5 to 10 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). Further preferably, it is 1 to 5 parts by mass. By setting the content of the antistatic agent (D) within the above range, the antistatic property can be effectively exhibited, and deterioration in physical properties such as optical properties and durability can be prevented.

(6) Various additives

Various additives generally used for the acrylic adhesive may be added to the adhesive composition P as needed, for example, a dispersant (for example, an alkylene glycol dialkyl ether), a tackifier, an antioxidant, and an ultraviolet absorption may be added. Agent, light stabilizer, softener, filler, refractive index modifier, and the like. In addition, the adhesive composition P is a component which is a mixture of various components remaining in the adhesive layer as it is or in a state of being reacted, and is removed in a drying process or the like, for example, a polymerization solvent or a diluent solvent to be described later. It is not included in the adhesive composition P.

(7) Adhesive composition ‧ Adhesive manufacturing method

The adhesive composition P can be produced by producing a (meth) acrylate copolymer (A), and the obtained (meth) acrylate copolymer (A) and an isocyanate crosslinking agent (B), It is produced by mixing a decane coupling agent (C), an antistatic agent (D), an additive, etc. which are added as needed.

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 as needed. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone. Two or more types may be used in combination.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more kinds thereof may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis (cyclohexane). Alkan 1-nitrile), 2,2'-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- Hydroxymethyl propyl Nitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane, and the like.

Examples of the organic peroxide include benzammonium peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and Di-(2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxy neodymidine, tert-butyl peroxypivalate, (3,5,5-trimethylhexyl) Peroxide, dipropyl decyl peroxide, diethyl hydrazine peroxide, and the like.

Further, in the above polymerization process, the weight average molecular weight of the obtained polymer can be adjusted by blending a chain transfer agent such as 2-mercaptoethanol.

After obtaining the (meth) acrylate copolymer (A), the isocyanate crosslinking agent (B) is added to the solution of the (meth) acrylate copolymer (A), and the decane coupling agent (C) is added as needed, The antistatic agent (D), an additive, a diluent solvent, and the like are sufficiently mixed to obtain an adhesive composition P (coating solution) diluted with a solvent.

As a diluent solvent for diluting the adhesive composition P as a coating solution, for example, an aliphatic hydrocarbon such as hexane, heptane or cyclohexane; an aromatic hydrocarbon such as toluene or xylene; methylene chloride or chlorine can be used. Halogenated hydrocarbons such as ethylene; alcohols such as methanol, ethanol, propanol, butanol, 1-methoxy-2-propanol; acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone Ketone; esters such as ethyl acetate and butyl acetate; and cellosolve such as ethyl cellosolve.

The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they are within the coatable range, and may be appropriately selected depending on the case. For example, the concentration of the adhesive composition P is diluted to 10 to 40% by mass. In addition, when the coating solution is obtained, the addition of a diluent solvent or the like is not a necessary condition as long as it is sticky. The viscosity of the composition P is a viscosity at which coating can be performed, and the dilution solvent may not be added. In this case, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth) acrylate copolymer (A) is directly used as a diluent solvent.

The adhesive constituting the adhesive layer 1 of the present embodiment is obtained by the adhesive composition P, specifically, the adhesive composition P is crosslinked. Crosslinking of the adhesive composition P can be carried out by heat treatment. In addition, the drying treatment at the time of volatilization of the dilution solvent of the adhesive composition P may be used as the heat treatment.

When the heat treatment is performed, 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, and particularly preferably from 50 seconds to 2 minutes. After the heat treatment, a curing period of about 1 to 2 weeks under normal temperature (for example, 23 ° C, 50% RH) may be set as needed. When the curing period is required, when the adhesive layer having a predetermined physical property is formed after the curing period, and the curing period is not required, the adhesive layer is formed after the heat treatment is completed.

By the above heat treatment (and curing), the (meth) acrylate copolymer (A) is crosslinked by the isocyanate crosslinking agent (B) to form a three-dimensional network structure.

(8) Thickness of the adhesive layer

The thickness of the pressure-sensitive adhesive layer 1 is usually in the range of 5 to 100 μm, preferably 10 to 60 μm, but from the viewpoint of exhibiting excellent durability, warpage suppression property, and heat unevenness by the pressure-sensitive adhesive layer 1, 10~50μm is preferred, and 15~30μm is particularly good.

2. Polarizer

(1) Structure

As shown in FIG. 1, the polarizing plate 2A of the present embodiment has a structure in which the first protective layer 22, the polarizer 21, and the second protective layer 23 are laminated in this order. With this configuration, the polarizing plate 2A is excellent in mechanical strength and chemical resistance. Further, 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.

(2) polarizer

The polarizer 21 is preferably composed of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and aligned.

The polyvinyl alcohol-based resin constituting the polarizer 21 can be obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, vinyl acetate and other monomer copolymers copolymerizable therewith are exemplified. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.

The degree of saponification 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 can be further modified. For example, polyvinyl formal or polyvinyl acetal modified with an aldehyde may also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually in the range of 1,000 to 10,000, preferably 1,500 to 5,000.

The polarizer 21 as described above is preferably produced by the following process: the uniaxial stretching of the polyvinyl alcohol resin film; the dyeing and adsorption of the polyvinyl alcohol resin film by the dichroic dye The dichroic dye; and the polyvinyl alcohol-based resin film in which the dichroic dye is adsorbed by the aqueous boric acid solution.

The uniaxial stretching can be carried out before the dyeing with the dichroic dye, simultaneously with the dyeing with the dichroic dye, or after the dyeing with the dichroic dye. When uniaxially stretching after dyeing with a dichroic dye, the uniaxial stretching can be carried out before the boric acid treatment or during the boric acid treatment. Of course, uniaxial stretching can also be performed at these multiple stages. When performing uniaxial stretching, it may be extended to a single axis between rolls having different circumferential speeds, or may be extended to a single axis using a heat roll. Further, it may be a dry stretching which is extended in the atmosphere, or may be a wet stretching which is extended in a state of being swollen by a solvent. The stretching ratio is usually about 4 to 8 times.

When the polyvinyl alcohol-based resin film is dyed with a dichroic dye, for example, the polyvinyl alcohol-based resin film may be immersed in an aqueous solution containing a dichroic dye. Specifically, iodine or a dichroic organic dye can be used as the dichroic dye.

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

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in the aqueous boric acid 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 using iodine as a dichroic pigment, It is preferred that the aqueous boric acid solution contains potassium iodide. The content of potassium iodide in the aqueous boric acid solution is usually from 2 to 20 parts by mass, preferably from 5 to 15 parts by mass, per 100 parts by mass of water. The immersion time in the aqueous boric acid 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 aqueous boric acid 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 carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. After washing with water, it was dried to obtain a polarizer 21. The water temperature in the water washing treatment is usually about 5 to 40 ° C, and the immersion time is usually about 2 to 120 seconds. The drying treatment thereafter is usually carried out using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 °C. In addition, the drying treatment time is usually about 120 to 600 seconds.

The polarizer 21 of the present embodiment has a thickness of 1 to 20 μm and is a thinner film than a normal polarizer. When the thickness of the polarizer 21 is less than 1 μm, sufficient polarizing performance cannot be exhibited. In addition, when the thickness of the polarizer 21 exceeds 20 μm, the warpage suppressing effect and the heat-resistant unevenness effect of the adhesive layer 1 are exceeded, and warpage or thermal unevenness occurs in the display panel. From this point of view, the thickness of the polarizer 21 is preferably 3 to 18 μm, and particularly preferably 5 to 15 μm.

(3) Protective layer

The first protective layer 22 is preferably made of a transparent resin film. The transparent resin film constituting the first protective layer 22 may be either an unstretched film or a film that is uniaxially or biaxially stretched.

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

As the amorphous polyolefin-based resin used for the first protective layer 22, a cycloolefin-based resin is preferable. Examples of the cycloolefin-based resin include ring-opening shift polymerization of norbornene or a derivative thereof obtained by reacting cyclopentadiene with an olefin by Diels-Alder reaction, followed by ring-opening shift polymerization. a resin obtained by hydrogenation; a ring-opening shift of tetracyclododecene or a derivative thereof obtained by reacting Dicyclopentadiene with an olefin or a methacrylate by Diels-Alder reaction as a monomer After the polymerization, the resin obtained by the hydrogenation is further subjected to ring-opening in the same manner using two or more kinds selected from the group consisting of norbornene, tetracyclododecene, and derivatives thereof, and other cyclic polyolefin monomers. After the shift polymerization, a resin obtained by hydrogenation, a resin obtained by addition-polymerization of norbornene, tetracyclododecene, or a derivative thereof with a vinyl compound having a vinyl group or the like. Examples of the commercially available amorphous polyolefin-based resin include "ARTON" by JSR CORPORATION, "ZEONEX" and "ZEONOR" of Zeon Corporation, "APO" of Mitsui Chemicals, Inc., and "APEL". When the amorphous polyolefin-based resin is formed into a film and used as a film, a film can be formed by a known method such as a solvent casting method or a melt extrusion method.

The cellulose-based resin is a resin obtained by esterifying at least a part of a hydroxyl group in cellulose, and may be a mixed ester in which a part is acetated and partially esterified. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetamino cellulose resin. Specific examples of the acetaminophen-based resin include triacetonitrile cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. As a thin layer made of such an acetaminophen-based resin For the commercially available product of the film, for example, "Fujitac TD80", "Fujitac TD80UF" and "Fujitac TD80UZ" manufactured by FUJIFILM Corporation; "KC8UX2M", "KC2UA" and "Konica Minolta Opto Products Co., Ltd." manufactured by Konica Minolta Opto Products Co., Ltd. KC8UY" and so on.

A cellulose resin film to which an optical compensation function is imparted can also be used. Examples of the optical compensation film include a film containing a compound having a phase difference adjustment function in a cellulose resin, and a compound having a phase difference adjustment function coated on the surface of the cellulose resin; A film obtained by stretching a cellulose resin uniaxially or biaxially. Examples of the optical compensation film of the cellulose-based resin which is commercially available are "Wide view Film WV BZ 438" manufactured by FUJIFILM Corporation and "Wide view Film WV EA", manufactured by Konica Minolta Opto Products Co., Ltd. "KC4FR-1" and "KC4HR-1", etc.

The first protective layer 22 is preferably composed of the above-mentioned cellulose resin, preferably composed of a cellulose ester resin, particularly preferably composed of an acetaminocellulose resin, and further preferably composed of triacetyl cellulose. The display panel obtained by forming the first protective layer 22 from triacetyl cellulose is less likely to warp under high temperature conditions, and is less likely to cause thermal unevenness.

The thickness of the first protective layer 22 is preferably 5 to 120 μm, more preferably 10 to 120 μm, particularly preferably 10 to 85 μm, and further preferably 10 to 30 μm. When the thickness of the first protective layer 22 is 5 μm or more, the polarizer 21 can be sufficiently protected. In addition, when the thickness of the first protective layer 22 is 120 μm or less, the warpage suppressing effect and the heat-resistant unevenness effect of the adhesive layer 1 can be sufficiently exhibited.

Further, the thickness of the first protective layer 22 is opposite to that of the polarizer 21 The ratio of the thickness is preferably 1.0 to 6.0, particularly preferably 1.4 to 4.0, and further preferably 1.6 to 3.8. By setting the ratio within the above range, the warpage suppressing effect and the heat unevenness effect of the adhesive layer 1 can be sufficiently exhibited.

On the other hand, the second protective layer 23 of the present embodiment is composed of a cycloolefin resin or triacetyl cellulose, and is usually composed of a transparent resin film containing a cycloolefin resin or triacetyl cellulose as a main component. The transparent resin film may be either an unstretched film or a film that is uniaxially or biaxially stretched.

The second protective layer 23 adjacent to the adhesive layer 1 is composed of a cycloolefin-based resin or triacetyl cellulose which is excellent in optical isotropy. Thereby, the obtained polarizing plate 2A can suppress the fall of optical performance to the minimum. In addition, from the viewpoint of achieving optical properties while maintaining optical properties, the second protective layer 23 is preferably made of a cycloolefin resin.

As the cycloolefin-based resin constituting the second protective layer 23, a cycloolefin-based resin exemplified as the first protective layer 22 can be used. Among them, a dicyclopentadiene resin is preferred. As a commercial product of the cycloolefin resin, "ZEONOR" of Zeon Corporation is particularly preferable.

As a commercial item of triacetonitrile cellulose constituting the second protective layer 23, "KC2UA" manufactured by Konica Minolta Opto Products Co., Ltd. is particularly preferable.

Further, the first protective layer 22 and the second protective layer 23 may be composed of the same type of material (transparent resin film), or may be composed of different types of materials (transparent resin film).

The thickness of the second protective layer 23 of the present embodiment is 5 to 30 μm. When the thickness of the second protective layer 23 is less than 5 μm, the manufacturing process of the polarizing plate 2A is performed. In the middle, the handleability of the second protective layer 23 is difficult, and the ability to protect the polarizer 21 is also lowered. When the thickness of the second protective layer 23 exceeds 30 μm, the thickness of the obtained polarizing plate 2A cannot be met. From this viewpoint, the thickness of the second protective layer 23 is preferably 10 to 25 μm, and particularly preferably 12 to 24 μm.

Further, the ratio of the thickness of the second protective layer 23 to the thickness of the polarizer 21 is 1.0 to 5.0. When the ratio is less than 1.0, the heat shrinkage retention function for the polarizer 21 is insufficient, and if the ratio exceeds 5.0, the thin film of the polarizing plate 2A cannot be handled. From this point of view, the ratio of the thickness of the second protective layer 23 to the thickness of the polarizer 21 is preferably from 1.3 to 4.0, and particularly preferably from 1.5 to 3.6.

Furthermore, from the viewpoint of preventing thermal contraction of the polarizer 21, the ratio of the total thickness of the first protective layer 22 and the second protective layer 23 to the thickness of the polarizer 21 is preferably 3.0 or more. In addition, although the upper limit is not particularly limited, it is preferable to be about 8.0 or less in consideration of the request for thinning of the polarizing plate 2A.

Further, the first protective layer 22 and the second protective layer 23 (hereinafter collectively referred to as "protective layers 22 and 23") may also contain an ultraviolet absorber. This is because the liquid crystal cell can be protected from ultraviolet light deterioration by disposing the protective layer containing the ultraviolet absorber on the viewing side of the liquid crystal cell.

Further, before the protective layers 22 and 23 are bonded to the polarizer 21, the bonding surface can be subjected to an easy subsequent treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment, or the like. Further, the surface of the protective layers 22 and 23 opposite to the bonding surface of the polarizer 21 may have various places such as a hard coat layer, an antireflection layer, and an antiglare layer. The management layer.

(4) adhesive layer

The adhesive which can be sandwiched between the polarizer 21 and the first protective layer 22 and/or the adhesive layer between the polarizer 21 and the second protective layer 23 can be depending on the type and purpose of the object to be placed. Appropriate use of appropriate. For example, a solvent-type adhesive, an emulsion type adhesive, a water-based adhesive, a pressure-sensitive adhesive, a rewet adhesive, a polycondensation adhesive, a solventless adhesive, a film adhesive, and a hot melt type may be mentioned. Agents, etc.

A preferred adhesive agent constituting the above-mentioned adhesive is a water-based adhesive, and a representative example thereof is a polyvinyl alcohol-based resin. A commercially available polyvinyl alcohol-based resin which may be a water-based adhesive, for example, KURARAY "KL-318" manufactured by CO., LTD.

The above aqueous binder 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 or the like is preferable, and an epoxy group compound is particularly preferable. As a commercial product of a crosslinking agent, for example, "Sumirez Resin 650 (30)" which is an aqueous solution of glyoxal or a water-soluble epoxy compound sold by Sumika Chemtex Company, Limited, etc. are mentioned.

As another preferable adhesive agent, an adhesive agent composed of an epoxy resin composition containing an epoxy resin which is cured by irradiation with an active energy ray or heating is exemplified. When the adhesive is used, the adhesion between the films can be carried out by irradiating the adhesive layer sandwiched between the films with an active energy ray or heating to cure the curable epoxy resin contained in the adhesive. Hardening of an epoxy resin based on irradiation of an active energy ray or heating, by cationic polymerization of an epoxy resin Preferably, the epoxy resin in the present specification means a compound having two or more epoxy groups in the molecule.

From the viewpoint of weather resistance, refractive index, and cationic polymerizability, the epoxy resin contained in the curable epoxy resin composition of the adhesive is preferably an epoxy resin containing no aromatic ring in the molecule. As such an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are illustrated.

(5) Method of manufacturing polarizing plate

The production of the polarizing plate 2A can be carried out by a usual method. Hereinafter, a method of producing a water-based adhesive as the above-mentioned adhesive will be described as an example.

First, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surface of the protective layers 22 and 23. The formation of the subsequent agent layer can be performed, for example, by 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. In addition, it is also possible to continuously supply the polarizer 21 and the protective layers 22 and 23 so that the bonding surfaces of both of them are inside, and to form an adhesive between them. After applying the adhesive, heat treatment is performed as needed to evaporate water, thereby drying the adhesive layer.

The film thickness of the subsequent layer can be arbitrarily set according to the characteristic design of the polarizing plate 2A. However, from the viewpoint of reducing the cost of the adhesive material, the smaller one is preferable, and the viewpoint of suppressing defects such as bubbles or foreign matter at the time of bonding is considered. In view of the above, the larger one is preferable, and from the viewpoint of adhesion and durability, it is preferably carried out in an optimum range determined for each combination of the adherend and the adhesive. It is usually 0.005 to 10 μm, preferably 0.01 to 5 μm, and more preferably 0.03 to 1 μm.

When the polarizer 21 and the protective layers 22, 23 are followed, One or both of the bonding surfaces may be subjected to an easy subsequent treatment such as corona discharge treatment, plasma treatment, flame treatment, primer treatment, and anchor coating treatment before forming the coating layer of the adhesive.

After the adhesive layer is formed 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 bonded to the other surface of the polarizer 21 . Thereby, the polarizing plate 2A in which the first protective layer 22, the polarizer 21, and the second protective layer 23 are laminated can be obtained.

The total thickness of the polarizing plate 2A is preferably from 15 to 170 μm, and is preferably from 20 to 100 μm, and particularly preferably from 30 to 80 μm from the viewpoint of reducing the thickness of the mobile communication application and maintaining the polarization performance.

3. Peeling piece

A release sheet may be laminated on the surface (the lower surface in FIG. 1) of the adhesive layer 1 of the present embodiment opposite to the polarizing plate 2A.

As the release sheet, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or a polyethylene terephthalate can be used. Diester film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionic polymer resin film, ethylene-(meth)acrylic acid A copolymer film, an ethylene-(meth)acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, or the like. In addition, such crosslinked films can also be used. It may also be such a laminated film.

It is preferred to carry out a release treatment on at least one side of the release sheet (particularly, a release surface that is in contact with the adhesive layer). Examples of the release agent used in the release treatment include an alkyd type, an anthrone type, a fluorine type, and an unsaturated polyester type. A polyolefin-based or wax-based release agent. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property on the peeling sheet, and the surface which carried out the peeling process, and the surface which shows the peeling-re-

When a release sheet is laminated on both surfaces of the adhesive layer, one of the release sheets is used as a heavy release release sheet having a large peeling force, and the other release sheet is used as a light release type release sheet having a small peeling force. good.

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

4. Method for manufacturing polarizing plate with adhesive layer

As an example of the method of producing the polarizing plate 10A with the adhesive layer, first, the coating solution of the adhesive composition P is applied to the peeling surface of the release sheet, and heat treatment is performed to form a coating film, and then, if necessary, On the coating film (the peeling surface is in contact with the coating film), another peeling sheet is laminated to obtain an adhesive sheet. The above coating film directly forms an adhesive layer when the curing period is not required, and forms an adhesive layer after the curing period when the curing period is required. The conditions regarding the heat treatment and the curing are as described above.

As a method of applying the above 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.

Next, the peeling sheet (light peeling type peeling sheet) of one side was peeled from the obtained adhesive sheet. Then, the second protective layer 23 of the polarizing plate 2A is superposed on the exposed adhesive layer, and the adhesive sheet and the polarizing plate 2A are press-bonded. Thereby, the polarizing plate 10A (with a peeling sheet) with the above-mentioned adhesive layer was obtained.

As a method of manufacturing the polarizing plate 10A with an adhesive layer attached thereto In another example, a solution (coating solution) containing the above-described adhesive composition P is applied onto a release surface of a release sheet, and after heat treatment to form a coating film, the second protective layer 23 of the polarizing plate 2A is superposed on the coating layer. membrane. When the above-mentioned coating film requires a curing period, the adhesive layer 1 is formed at intervals of the curing period, and when the curing period is not required, the adhesive layer 1 is directly formed. Thereby, the polarizing plate 10A (with a peeling sheet) with the above-mentioned adhesive layer was obtained.

[Second Embodiment]

Next, a polarizing plate with an adhesive layer according to a second embodiment of the present invention will be described. In the polarizing plate of the present embodiment, as shown in FIG. 2, the polarizing plate 10B with the adhesive layer of the present embodiment is configured to include a composite polarizing plate 2B and a layer laminated on the composite polarizing plate 2B (in FIG. 2 Adhesive layer 1 of the lower side). Further, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the side of the composite polarizing plate 2B, and the polarizing plate 10B to which the adhesive layer is attached may be used.

The adhesive layer 1 is composed of the above-described adhesive in the present embodiment.

The composite polarizing plate 2B of the present embodiment is configured to include a first retardation film 24 that is in contact with the adhesive layer 1, and a second phase difference that is located on the opposite side of the first retardation film 24 from the adhesive layer 1 side. a plate 25 (corresponding to the second protective layer of the present invention); a second adhesive layer 26 sandwiched between the first retardation film 24 and the second retardation film 25; and a layer of the second phase difference plate 25 a polarizer 21 on the side opposite to the side of the second adhesive layer 26; and a protective layer 27 (corresponding to the first protective layer of the present invention) laminated on the side opposite to the side of the second retardation film 25 of the polarizer 21 . Further, although not shown, it may be sandwiched between the polarizer 21 and the protective layer 27 and/or between the polarizer 21 and the second retardation film 25. Agent layer. The composite polarizing plate 2B can exhibit the viewing angle compensation performance satisfactorily.

(1) First phase difference plate

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

Further, it is preferable that the first retardation film 24 is provided with an in-plane retardation by extension. Thereby, the viewing angle compensation performance is further improved.

The styrene resin constituting the phase difference expression layer 242 may be a homopolymer of styrene or a derivative thereof, or may be a binary or binary copolymer of styrene or a derivative thereof and another copolymerizable monomer. . The styrene derivative refers to a compound in which other groups are bonded to styrene, and examples thereof include o-methylstyrene, m-methylstyrene, p-methylstyrene, and 2,4-. An alkyl styrene such as dimethyl styrene, o-ethyl styrene or p-ethyl styrene, or such as hydroxyphenyl a substituted benzene having a hydroxyl group, an alkoxy group, a carboxyl group or a halogen introduced into a benzene nucleus of styrene such as a olefin, a third butoxy styrene, a vinyl benzoic acid, an o-chlorostyrene or a p-chlorostyrene Ethylene and the like.

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

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

In addition, as the styrene resin constituting the phase difference expression layer 242, a styrene 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 10 to 100 μm. By making the thickness of the phase difference expression layer 242 10 μm or more, a sufficient retardation value can be expressed by the extension. On the other hand, when the thickness of the phase difference expression layer 242 is 100 μm or less, the impact strength is high, and the change in retardation based on the external stress is small, and when it is applied to a liquid crystal display device, it is difficult to cause thermal unevenness.

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

Examples of the (meth)acrylic resin include a homopolymer of an alkyl methacrylate or an alkyl acrylate, or an alkyl methacrylate and A copolymer of an alkyl acrylate or the like. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Further, examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. Such a (meth)acrylic resin can be used as a general-purpose (meth)acrylic resin. Further, the (meth)acrylic resin also includes a material called an impact-resistant (meth)acrylic resin, or a structure having a glutaric anhydride structure or a lactone ring structure in the main chain, which is called high heat resistance (methyl group). ) Acrylic resin.

It is preferred that the rubber particles blended in the (meth)acrylic resin are acrylic. The acrylic rubber particles are rubber-elastic particles obtained by polymerizing an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate as a main component and polymerizing in the presence of a polyfunctional monomer.

The rubber particles may be formed into a homogeneous particle shape by a material having rubber elasticity, or may be a multilayer structure having at least one rubber elastic layer. Examples of the acrylic rubber particles having a multilayer structure include particles having rubber elasticity as described above and having a core surrounded by a hard alkyl methacrylate polymer; and hard methacrylic acid. The base ester-based polymer is used as a core, and the periphery thereof is covered with an acrylic polymer having rubber elasticity as described above; further, the periphery of the hard core is covered with a rubber-elastic acrylic polymer, and further around it Covered with a hard alkyl methacrylate polymer or the like.

It is preferred that the rubber particles have an average diameter of about 50 to 400 nm. The average diameter of the rubber particles can be measured by a laser diffraction scattering method.

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

The (meth)acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243 can be used in a state in which a (meth)acrylic resin and acrylic rubber particles are mixed. Examples of commercially available products of a (meth)acrylic resin ((meth)acrylic resin composition) containing acrylic rubber particles are sold under the trade name: Sumitomo Chemical Co., Ltd. "HT55X" or "TechnolloyS001" sold.

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 less is preferable, and particularly preferably A (meth)acrylic resin composition of 110 ° C or less. In other words, the glass transition temperature (Tg) of the phase difference expression layer 242 does not overlap with the glass transition temperature (Tg) of the first acrylic resin 241 and the second acrylic resin layer 243, and the phase difference expression layer 242 has a ratio. The glass transition temperature (Tg) of the first acrylic resin layer 241 and the second acrylic resin layer 243 is preferably higher.

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, film formation can be easily performed, and when the thickness is 100 μm or less, the retardation of the first acrylic resin layer 241 and the second acrylic resin layer 243 can be ignored. Moreover, it is preferable that the thickness of the first acrylic resin layer 241 is substantially the same as the thickness of the second acrylic resin layer 243.

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

When the first retardation film 24 is produced, for example, a styrene resin and a (meth)acrylic resin composition containing rubber particles may be coextruded and then extended. The extension can be performed by longitudinal uniaxial stretching, tenter lateral uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching, etc., as long as it is extended to obtain a desired retardation value. In addition to the above methods, after the single-layer film (the phase difference expression layer 242, the first acrylic resin layer 241, and the second acrylic resin layer 243) is separately formed, the heat fusion may be performed after the heat fusion. , extending its laminate.

In addition, from the viewpoint of maintaining sufficient performance and meeting the requirements for thinning in mobile communication applications, the total thickness of the first retardation film 24 after stretching is preferably 5 to 100 μm, and more preferably 10 to 50 μm. 15~30μm is especially good.

The surface of the first retardation film 24 that is in contact with the adhesive layer 1 is composed of the first acrylic resin layer 241. In this case, the adhesion of the adhesive layer 1 to the first acrylic resin layer 241 is also high. Therefore, the polarizing plate 10B with the adhesive layer is excellent in durability under high temperature conditions, under moist heat conditions, under thermal shock, and the like.

(2) Second phase difference plate

The second retardation film 25 of the present embodiment corresponds to the second protective layer of the present invention. As the second retardation film 25, the second embodiment of the first embodiment can be used. The protective layer 23 is the same.

(3) 2nd adhesive layer

As the adhesive constituting the second adhesive layer 26, a known adhesive may be used, which may be a curable adhesive or a non-curable adhesive, but the viewpoint of suppressing dimensional change due to thermal contraction of the polarizing plate is considered. It is preferable to use an active energy ray-curable adhesive.

The active energy ray-curable adhesive may be a polymer having active energy ray-curable polymer as a main component, or a polymer having no active energy ray-curable polymer and active energy ray-curable polyfunctional monomer and / or a mixture of oligomers as a main component. Further, it may be a mixture of a polymer having active energy ray hardenability and a polymer having no active energy ray hardening property, or a polymer having active energy ray hardenability and an active energy ray hardening polyfunctional monomer. And/or a mixture of oligomers, which may also be a mixture of the three.

In the above, from the viewpoint of easily obtaining an adhesive which maintains adhesiveness and exhibits cohesive force, a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer and/or oligomer are used. The mixture is preferably a main component, and particularly preferably a mixture of a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer as a main component.

As a polymer having no active energy ray-curable property, a (meth) acrylate polymer (hereinafter referred to as "(meth) acrylate polymer (X)") having no active energy ray-curable group is comparatively good. (Meth)acrylate polymer (X) having a carbon number of 1 to 20 containing an alkyl group (methyl) The alkyl acrylate is preferred as the monomer constituting the polymer. Thereby, the obtained adhesive can exhibit better adhesion. Further, the (meth) acrylate polymer (X) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, and a monomer having a reactive functional group (containing a reactive functional group). Copolymers, and copolymers of other monomers used as needed are particularly preferred. When the (meth) acrylate polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, adhesion to a glass surface of a liquid crystal cell or the like can be improved, and It reacts with the crosslinking agent (Z) mentioned later, and forms a bridge|crosslinking structure.

Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. N-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (methyl) N-decyl acrylate, n-dodecyl (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate Wait. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferred, and n-butyl (meth) acrylate is particularly preferred. Further, these may be used alone or in combination of two or more.

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

The reactive functional group-containing monomer is preferably a monomer having a hydroxyl group in the molecule (hydroxy group-containing monomer) or a monomer having a carboxyl group in the molecule. (Carboxyl group-containing monomer), a monomer having an amine group in the molecule (an amine group-containing monomer), and the like. These reactive functional group-containing monomers may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-(meth)acrylate. A hydroxyalkyl (meth)acrylate such as hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate or 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. Among them, acrylic acid is preferred from the viewpoint of reactivity between the carboxyl group of the obtained (meth)acrylate polymer (X) and the crosslinking agent (Z) and copolymerization with other monomers. These may be used singly or in combination of two or more.

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

The (meth) acrylate polymer (X) is preferably a monomer having a reactive functional group containing 1 to 25% by mass as a monomer unit constituting the polymer, particularly preferably 1 to 20% by mass, further It is preferably contained in an amount of 2 to 5% by mass.

The polymerization state 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 million, and further preferably from 1.6 million to 2.2 million.

In addition, the (meth) acrylate polymer (X) can be used alone One type may be used in combination of two or more types.

Molecular weight excellent in compatibility with an active energy ray-curable polyfunctional monomer (hereinafter referred to as "active energy ray-curable compound (Y)") and (meth) acrylate polymer (X) A polyfunctional acrylate monomer of 1,000 or less is preferred.

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, and neopentane. Diol (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxy trimethyl acetic acid neopentyl glycol di (a) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, a bifunctional type such as bis(propyleneoxyethyl)isocyanurate or allylated cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri Methyl) acrylate, propionic acid modified dipentaerythritol tri(meth) acrylate, pentaerythritol tri-(meth) acrylate, propylene oxide modified trimethylolpropane tri(meth) acrylate, three ( 3-functional type such as acryloxyethyl)isocyanurate or ε-caprolactone modified tris(2-(methyl)propenyloxyethyl)isocyanurate; diglycerol tetra(A) Acrylate a tetrafunctional type such as an alcohol tetra(meth)acrylate; a 5-functional type such as propionic acid modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa(meth) acrylate; caprolactone modified dipentaerythritol hexa A 6-functional type such as a methyl acrylate or the like. These may be used alone or in combination of two or more.

The content of the active energy ray hardening compound (Y) is relative to (A) The acrylate polymer (X) is preferably used in an amount of from 1 to 50 parts by mass, more preferably from 5 to 30 parts by mass, even more preferably from 10 to 20 parts by mass, per 100 parts by mass of the acrylate polymer (X).

It is also preferred that the active energy ray-curable adhesive contains a crosslinking agent (Z). When the active energy ray-curable adhesive contains a (meth) acrylate polymer (X) containing a reactive functional group-containing monomer and a crosslinking agent (Z) as a monomer unit constituting the polymer, if the adhesive is to be adhered When the agent is heated or the like, the crosslinking agent (Z) is reacted with a reactive functional group of the reactive functional group-containing monomer constituting the (meth) acrylate polymer (X). Thereby, the structure in which the (meth) acrylate polymer (X) is crosslinked by the crosslinking agent (Z) is formed, and the cohesive force of the obtained adhesive is improved.

The crosslinking agent (Z) may be reacted with a reactive functional group of the (meth) acrylate polymer (X), and examples thereof include an isocyanate crosslinking agent and an epoxy crosslinking agent. An amine crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent, an anthraquinone crosslinking agent, an aldehyde crosslinking agent, an oxazoline crosslinking agent, a metal alkoxide crosslinking agent, and a metal chelate A compound-based crosslinking agent, a metal salt-based crosslinking agent, an ammonium salt-based crosslinking agent, and the like. As the isocyanate crosslinking agent, the same as the above isocyanate crosslinking agent (B) can be used. Further, the crosslinking agent (Z) may be used alone or in combination of two or more.

The content of the crosslinking agent (Z) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, even more preferably 100 parts by mass of the (meth) acrylate polymer (X). It is 0.1 to 1 part by mass.

The active energy ray-curable adhesive may further contain various additives as needed, for example, a photopolymerization initiator, a decane coupling agent, a refractive index adjuster, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, and a light stabilizer. Agents, softeners, fillers, etc.

When ultraviolet rays are used as the active energy ray for curing the active energy ray-curable adhesive, it is preferred that the active energy ray-curable adhesive contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylamino acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1 -ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4-(2-hydroxyethyl) Oxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichloroethylene Benzophenone, 2-methylindole, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethyl ketal, p-dimethyl Amino benzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzhydrazide Base-diphenyl-phosphine oxide and the like. These may be used singly or in combination of two or more.

The photopolymerization initiator is preferably used in an amount of from 0.1 to 20 parts by mass, more preferably from 1 to 20 parts by mass, per 100 parts by mass of the active energy ray-curable compound (Y) in the active energy ray-curable adhesive. 12 parts by mass.

Further, from the viewpoint of improving the adhesion of the obtained adhesive to the film, the active energy ray-curable adhesive preferably contains a decane coupling agent. As a decane coupling agent, having at least one alkoxydecane in the molecule It is preferred that the organic ruthenium compound has good compatibility with the adhesive component and has light transmittance.

As the decane coupling agent, for example, in addition to the epoxy group-containing decane coupling agent (C1) and the fluorenyl decane-containing coupling agent (C2), a polymerizable unsaturated hydrazine-containing compound (for example, vinyltrimethoxy) may be mentioned. Alkyl decane, vinyl triethoxy decane, methacryloxypropyl trimethoxy decane, etc., an amine group-containing hydrazine compound (for example, 3-aminopropyltrimethoxydecane, N-(2-amine) Benzyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, etc., 3-chloropropyltrimethoxy A decyl alkane, a 3-isocyanate propyl triethoxy decane, or at least one of these, and an alkyl-containing hydrazine compound (eg, methyl triethoxy decane, ethyl triethoxy decane, methyl trimethyl a condensate of oxydecane, ethyltrimethoxydecane, or the like. These may be used alone or in combination of two or more.

The content of the decane coupling agent is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, even more preferably 0.1 to 1 part by mass, per 100 parts by mass of the (meth) acrylate polymer (X). .

Further, the polymer having the active energy ray-curable property is a (meth) acrylate (co)polymer having a functional group (active energy ray-curable group) having an active energy ray-curable property introduced into a side chain. good.

The thickness of the second adhesive layer 26 is usually about 1 to 50 μm, preferably 1 to 20 μm, and particularly preferably 2 to 7 μm. If the adhesive layer is too thin, the adhesiveness is lowered, and if it is too thick, the adhesive is likely to be extruded and the like.

(4) Polarizer

As the polarizer 21, the polarizer 21 of the polarizing plate 2A described above can be used. The same.

(5) Protective layer

The protective layer 27 of the present embodiment corresponds to the first protective layer of the present invention. As the protective layer 27, the same as the first protective layer 22 of the first embodiment can be used.

(6) adhesive layer

The adhesive layer may be sandwiched between the polarizer 21 and the protective layer 27 and/or between the polarizer 21 and the second retardation film 25, and the same adhesive layer as the polarizing plate 2A may be used.

(7) Method of manufacturing composite polarizing plate

The manufacture of the composite polarizing plate 2B can be carried out by a usual method. Hereinafter, a method of producing a water-based adhesive as the above-mentioned adhesive will be described as an example.

First, a coating film of an adhesive constituting the second adhesive layer 26 is formed on the peeling surface of the release sheet. Specifically, the coating liquid of the adhesive constituting the second adhesive layer 26 is applied onto 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 surface of the second phase difference plate 25 and the protective layer 27. The formation of the adhesive layer can be carried out by the same method as the method of manufacturing the polarizing plate 2A described above. In addition, the thickness of the adhesive layer and the ease of subsequent treatment are also the same.

After the adhesive layer is formed as described above, the protective layer 27 is bonded to one surface of the polarizer 21 via the adhesive layer, and the second retardation film 25 is bonded to the other surface of the polarizer 21 to obtain a protective layer. 27. A laminate (polarizing plate) comprising a polarizer 21 and a second retardation film 25.

Then, a coating film of the adhesive constituting the second adhesive layer 26 on the release sheet is bonded to the surface of the obtained laminate on the second retardation film 25 side. Then, the active energy ray is irradiated through the release sheet to cure the coating film of the adhesive, and the coating film is used as the second adhesive layer 26.

Here, the active energy ray means an energy quantum in an electromagnetic wave or a charged particle beam, and specifically, an ultraviolet ray or an electron beam is mentioned. Among the active energy rays, ultraviolet rays that are easy to handle are particularly excellent.

The irradiation of ultraviolet rays can be carried out by a high pressure mercury lamp, a metal halide lamp, a molten 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 amount is preferably from 50 to 10,000 mJ/cm ² , more preferably from 80 to 5,000 mJ/cm ² , particularly preferably from 100 to 1,000 mJ/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 1000 krad.

Finally, the release sheet is peeled off from the second adhesive layer 26 formed as described above, and the surface on the second acrylic resin layer 243 side of the first retardation film 24 is bonded to the exposed second adhesive layer 26 . . Thereby, the composite polarizing plate 2B in which the protective layer 27, the polarizer 21, the second retardation film 25, the second adhesive layer 26, and the first retardation film 24 are laminated is obtained.

Further, 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 polarizing plate with adhesive layer

As an example of the method for producing the polarizing plate 10B with the adhesive layer, the adhesive sheet prepared by peeling off the two-layer layer of the adhesive layer is used as the adhesive sheet of the present embodiment, and the peeling sheet on the peeling side (light peeling type) Stripping)). Of course Thereafter, the first retardation film 24 of the composite polarizing plate 2B is superposed on the exposed adhesive layer, and the adhesive sheet and the composite polarizing plate 2B are press-bonded. Thereby, the polarizing plate 10B (with a peeling sheet) with the above-mentioned adhesive layer is obtained.

In another example of the method for producing the polarizing plate 10B with the adhesive layer, the coating solution of the adhesive composition P is applied onto the peeling surface of the release sheet, and heat treatment is performed to form a coating film, and then the composite polarizing plate 2B is applied. The first retardation film 24 is superposed on the coating film. When the above-mentioned coating film requires a curing period, the adhesive layer 1 is formed at intervals of the curing period, and when the curing period is not required, the adhesive layer 1 is directly formed. Thereby, the polarizing plate 10B (with a peeling sheet) with the above-mentioned adhesive layer was obtained.

5. Physical properties of polarizing plate with adhesive layer

The adhesive force of the polarizing plates 10A and 10B with the adhesive layer of the present embodiment is preferably 0.5 to 20 N/25 mm, and particularly preferably 1 to 10 N/25 mm, with respect to the adhesion of the alkali-free glass. Thereby, the polarizing plate with the adhesive layer is excellent in durability. Further, from the viewpoint of excellent reworkability, the adhesion is preferably 1.5 to 7 N/25 mm. In addition, the adhesive force mentioned here is an adhesion force measured by the 180 degree peeling method basically according to JIS Z0237:2009, and is set as follows: setting measurement sample is width 25 mm, length 100 mm, and this measurement sample is set. After pressurizing at 0.5 MPa and 50 ° C for 20 minutes and adhering to the object, it was allowed to stand under normal pressure, 23 ° C, and 50% RH for 24 hours, and then measured at a peeling speed of 300 mm/min. When the adhesion is within the above range and adhered to the liquid crystal cell, warpage, surface peeling, or the like can be prevented.

Further, the polarizing plates 10A and 10B with the adhesive layer of the present embodiment are further bonded to the above-mentioned object, and further at 23 ° C, 50% RH. The adhesion after 14 days of placement (adhesive force after 14 days of attachment) is preferably 1 to 20 N/25 mm, and particularly preferably 3 to 9 N/25 mm. By suppressing the improvement of the adhesive force over time, the polarizing plates 10A and 10B with the adhesive layer of the present embodiment are excellent in reworkability, and can be easily reattached after being attached to the liquid crystal cell.

In addition, the polarizing plates 10A and 10B with the adhesive layer of the present embodiment are adhered to the above-mentioned object, and are adhered to the adhesive body at 50° C. and 50% RH for 2 days (adhesive force at 50° C.) The adhesion after 2 days is preferably from 1 to 20 N/25 mm from the viewpoint of durability, and is particularly preferably 6 to 12 N/25 mm from the viewpoint of reprocessing.

The surface resistivity of the adhesive layer of the polarizing plates 10A and 10B with the adhesive layer of the present embodiment is preferably 1.0 × 10 ¹² Ω/sq or less, more preferably 5.0 × 10 ¹¹ Ω/sq or less, further Preferably, it is 7.0×10 ¹⁰ Ω/sq or less. By setting the surface resistivity to the above value or less, it is possible to exhibit sufficient antistatic properties on the display panel. This surface resistivity can be achieved by including the above-mentioned antistatic agent (D) in the adhesive composition P. In addition, the measurement of the surface resistivity of the adhesive layer is performed in accordance with JIS K6911, and is specifically shown in the test example described later. In addition, 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 unevenness.

6. Use of polarizer with adhesive layer

A liquid crystal display device including a liquid crystal cell and a polarizing plate can be manufactured by using the polarizing plates 10A and 10B with an adhesive layer.

Specifically, the adhesive layer 1 of the polarizing plates 10A and 10B to which the adhesive layer is attached (when the release sheet is laminated, the peeling sheet is peeled off and exposed The adhesive layer 1) may be superposed on the desired surface of the liquid crystal cell and pressed. Thereby, a liquid crystal display device including the liquid crystal cell, the polarizing plate 2A, or the composite polarizing plate 2B can be obtained.

The polarizing plates 10A and 10B with the adhesive layer of the present embodiment are excellent in durability, and the adhesive layer can be suppressed even when the obtained liquid crystal display device is placed under high temperature conditions, under moist heat conditions or under thermal shock. The interface of 1 is warped or peeled off. For example, when the glass plate to which the polarizing plates 10A and 10B with the adhesive layer are attached is placed under high temperature conditions of 85 ° C or under hot humid conditions of 60 ° C and 90% RH for 250 hours, or -35 ° C is applied. In the case of thermal shock at ~70 ° C (30 minutes each, 200 cycles), it is possible to suppress occurrence of warping or surface peeling.

Further, the polarizing plates 10A and 10B with the adhesive layer of the present embodiment are excellent in stress relaxation property, and the obtained liquid crystal display device is less likely to warp under high temperature conditions, and further, it is difficult to cause thermal unevenness. For example, when the glass plate to which the polarizing plates 10A and 10B with the adhesive layer are attached is placed under high temperature conditions (for example, at 80 to 85 ° C) for 250 hours, it is not easily warped, and it is difficult to produce. Uneven heat. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a film, the liquid crystal display device is less likely to warp, and even if the liquid crystal cell is high-precision, heat unevenness is less likely to occur.

Here, the transparent conductive film may be present on the bonding surface of the liquid crystal cell and the adhesive layer 1, and even in this case, the corrosion of the transparent conductive film or the change in the resistance value of the transparent conductive film can be suppressed.

Examples of the transparent conductive film include metals such as platinum, gold, silver, and copper, tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc dioxide. Oxide, tin-doped indium oxide (ITO), zinc oxide-doped indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, etc. A compound such as a compound, a non-oxidizing compound such as lanthanum hexaboride, titanium nitride or titanium carbide.

The embodiments described above are described to facilitate the understanding of the present invention, and are not intended to limit the present invention. Therefore, all the design changes and equivalents belonging to the technical scope of the present invention are also included in the elements disclosed in the above embodiments.

[Examples]

Hereinafter, the present invention will be specifically described by way of Examples and the like, but the scope of the present invention is not limited to the Examples and the like.

[Example 1]

1. Manufacturing of polarizing plate

(1) Production of polarized photons

A polyvinyl alcohol film having a thickness of 75 μm, which is composed of polyvinyl alcohol having an average polymerization degree of about 2,400 and a degree of saponification of 99.9 mol% or more, is stretched by about 5 times in a dry uniaxial stretching manner, and further kept at a tension of 60 ° C. Immerse in pure water for 1 minute. Thereafter, it was immersed in an aqueous solution of iodine/potassium iodide/water in a mass ratio of 0.05/5/100 at 28 ° C for 60 seconds. Next, it was immersed at 72 ° C for 300 seconds in an aqueous solution of potassium iodide/boric acid/water having a mass ratio of 8.5/8.5/100. Then, after washing with pure water at 26 ° C for 20 seconds, it was dried at 65 ° C to obtain a polarizer in which iodine was adsorbed to polyvinyl alcohol. The thickness of the polarizer was 15 μm.

(2) Production of polarizing plate

Preparation of 3 parts by mass of carboxyl modified polyvinyl alcohol (KURARAY CO., LTD) Manufactured, trade name "KL-318") was dissolved in 100 parts by mass of water, and 1.5 parts by mass of a water-soluble epoxy resin, that is, a polydecylamine epoxy-based additive (Taoka Chemical Co., Ltd.) was added to the aqueous solution. An epoxy-based adhesive obtained by producing a product name "Sumirez Resin 650 (30)" and an aqueous solution having a solid concentration of 30% by mass). This epoxy-based adhesive is applied to one surface of the polarizer obtained by the above.

On the coating layer of the above epoxy-based adhesive, a triacetyl cellulose film (manufactured by Konica Minolta Opto Products Co., Ltd., trade name "KC2UA") having a thickness of 25 μm was applied as a saponification treatment as a surface. The first protective layer.

Then, on the other surface of the polarizer, an epoxy-based adhesive was applied in the same manner as described above, and a zero-phase retardation film made of a cyclic olefin resin having a thickness of 23 μm was bonded to the coating layer (Zeon The product name "ZEONOR" manufactured by Corporation is used as the second protective layer. Thereafter, the film was dried at 80 ° C for 5 minutes, whereby the first protective layer and the second protective layer were followed by a polarizer. After that, it was cured at 40 ° C for 168 hours to obtain a laminated first protective layer (layer thickness: 25 μm), a polarizer (extension ratio of 5 times, a layer thickness of 15 μm), and a second protective layer (layer thickness of 23 μm) to have a total thickness of 63 μm. Polarizer. Further, the ratio of the thickness of the first protective layer to the thickness of the polarizer was 1.67, and the ratio of the thickness of the second protective layer to the thickness of the polarizer was 1.53. Further, the ratio of the total thickness of the first protective layer and the second protective layer to the thickness of the polarizer was 3.2.

2. Manufacture of composite polarizing plate

(1) Formation of a coating film of an active energy ray curable adhesive

95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid Prepared (meth) acrylate polymer (X). The molecular weight of the (meth) acrylate polymer (X) was measured by the method described later, and as a result, the weight average molecular weight (Mw) was 2,000,000.

Tris(propylene oxyethyl) isocyanurate which is 100 parts by mass of the above (meth) acrylate polymer (X) as an active energy ray curable compound (Y) (polyfunctional monomer) (manufactured by TOAGOSEI CO., LTD., trade name "ARONIXM-315") 15 parts by mass of trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent (Z). Product name "CORONATEL") 0.3 parts by mass of a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone as a polymerization initiator in a mass ratio of 1:1 (manufactured by Chiba Specialty Chemicals Co., Ltd., 1.5 parts by mass of "IRGACURE 500") and 0.2 parts by mass of 3-glycidoxypropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403") as a decane coupling agent were mixed. The mixture was thoroughly stirred and diluted with ethyl acetate to obtain a coating solution of an active energy ray-curable adhesive.

A release-treated sheet of a release sheet (SP-PET3811, thickness: 38 μm manufactured by LINTEC Corporation) obtained by peeling off one side of a polyethylene terephthalate film by an anthrone-based release agent, and knife-coated After coating the coating solution of the obtained active energy ray-curable adhesive, the film was heat-treated at 90 ° C for 1 minute to form a coating film of the active energy ray-curable adhesive.

(2) Production of the first phase difference plate

The C having an average particle diameter of 200 nm constituting the first acrylic resin layer is blended. A methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "Technolloy S001") of about 20% by mass of the olefinic rubber particles, and a styrene-maleic anhydride copolymerized resin (NOVA) constituting the phase difference expression layer Chemicals Corporation., trade name "DYLARK D332"), and methacrylic resin (Sumitomo Chemical Co., Ltd.) containing about 20% by mass of acrylic rubber particles having an average particle diameter of 200 nm constituting the second acrylic resin layer. Manufactured under the trade name "Technolloy S001", three layers of co-extruding were carried out in this order to obtain a laminated film having a three-layer structure. The laminated film obtained was stretched to obtain a first retardation film (first acrylic resin layer/phase difference expression layer/second acrylic resin layer) having an in-plane retardation of 60 nm and a thickness of 25 μm.

(3) Production of composite polarizing plate

First, the aforementioned polarizing plate is prepared. The first protective layer and the second protective layer of the polarizing plate correspond to the protective layer of the composite polarizing plate produced here and the second retardation plate, respectively. In other words, a polarizing plate in which a protective layer, a polarizer, and a second retardation film are laminated is prepared.

The surface of the polarizing plate on the second retardation plate side is bonded to the coating film of the active energy ray-curable adhesive obtained by the above process (1), and the ultraviolet ray is irradiated through the release sheet under the following conditions to cause the adhesive. The coating film is hardened to form a second adhesive layer. After that, the release sheet is peeled off from the obtained second adhesive layer, and then the second acrylic layer of the first retardation film obtained by the above process (2) is bonded to the surface of the exposed second adhesive layer. The surface on the side of the resin layer. Thus, a composite polarized film having a total thickness of 93 μm, which is obtained by laminating a protective layer (first protective layer), a polarizer, a second retardation plate (second protective layer), a second adhesive layer, and a first retardation film, is obtained. board. In addition, the formed second adhesive layer The thickness is 5 μm.

<Ultraviolet irradiation conditions>

‧Use high pressure mercury lamp

‧illuminance 300mW/cm ² , light quantity 300mJ/cm ²

‧Using EYE GRAPHICS CO.,LTD. to manufacture "UVPF-A1" UV illuminance/light meter

3. Manufacture of polarizing plate with adhesive layer

(1) Preparation of (meth) acrylate copolymer

Preparation of (meth) acrylate copolymer by copolymerizing 87 parts by mass of n-butyl acrylate, 5 parts by mass of isobornyl acrylate, 5 parts by mass of 2-phenylethyl acrylate, and 3 parts by mass of 2-hydroxyethyl acrylate (A). The molecular weight of the (meth) acrylate copolymer (A) was measured by the method described later, and as a result, the weight average molecular weight (Mw) was 1.6 million. Further, according to the above compounding, the (meth) acrylate copolymer (A) had a hydroxyl value of 14.49 mgKOH/g and an acid value of 0 mgKOH/g.

(2) Preparation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained by the above process (1), trimethylolpropane modified xylylene diisocyanate as the isocyanate crosslinking agent (B) (Mitsui 0.2 parts by mass, manufactured by Chemicals, Inc., under the trade name "TAKENATE D110N", as a 3-glycidoxypropyltrimethoxydecane containing an epoxy decane coupling agent (C1) (Shin-Etsu Chemical Co., Ltd.) Manufactured, trade name "KBM403") 0.2 parts by mass of co-condensate of 3-mercaptopropyltrimethoxydecane and methyltriethoxydecane as a mercapto-decane-containing coupling agent (C2) (Shin-Etsu Chemical) Manufactured by Co., Ltd., Trade name ""X-411-1810", fluorenyl equivalent: 450 g/mole) 0.2 parts by mass, and N-octyl-4-methylpyridinium hexafluorophosphate as an antistatic agent (D) (room temperature 2.0 parts by mass of the solid ionic compound was mixed, and the mixture was thoroughly stirred and diluted with ethyl acetate to obtain a coating solution of the adhesive composition.

Here, each compounding (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. In addition, the details of the abbreviations 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

MA: Methyl acrylate

[Isocyanate crosslinking agent]

XDI: Trimethylolpropane modified xylylene diisocyanate (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D110N")

[antistatic agent]

Pry+PF6-: N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound at room temperature)

(3) Production of polarizing plate with adhesive layer

A release sheet which was subjected to a release treatment on one side of a polyethylene terephthalate film by an anthrone-based release agent (manufactured by LINTEC Corporation, SP-PET3811, The peeling-treated surface of the thickness: 38 μm) was applied to the coating solution of the obtained adhesive composition by a knife coater, and then heat-treated at 90 ° C for 1 minute to form a coating film of the adhesive composition.

Then, the polarizing plate obtained as described above is bonded to the coating film so that the surface of the second protective layer is in contact with the exposed surface of the coating film, and is cured at 23 ° C and 50% RH for 7 days. A polarizing plate with a first adhesive layer formed on the polarizing plate to form an adhesive layer was obtained. Further, the thickness of the formed adhesive layer was 20 μm.

In addition, the composite polarizing plate obtained as described above is bonded to the coating film at 23 ° C such that the surface of the first acrylic resin layer of the first retardation film is in contact with the exposed surface of the coating film. After curing at 50% RH for 7 days, a polarizing plate with a second adhesive layer formed on the composite polarizing plate to form an adhesive layer was obtained. Further, the thickness of the adhesive layer formed was 20 μm.

[Examples 2 to 13, Comparative Examples 1 to 7]

The type and ratio of each monomer constituting the (meth) acrylate copolymer (A), the weight average molecular weight of the (meth) acrylate copolymer (A), and the blending of the isocyanate crosslinking agent (B) A polarizing plate with the first and second adhesive layers was produced in the same manner as in Example 1 except that the amounts shown in Table 1 were changed.

Here, the weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

. GPC measuring device: manufactured by Tosoh Corporation, HLC-8020

. GPC column (passed in the following order): manufactured by Tosoh Corporation

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

. Determination of solvent: tetrahydrofuran

. Measuring temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)

A release sheet (SP-PET3801, thickness: 38 μm manufactured by LINTEC Corporation) in which one side of a polyethylene terephthalate film was peeled off by an anthrone-based release agent was used to prepare an adhesive sheet instead of the example or the comparative example. An optical film used in the production of a polarizing plate with an adhesive layer. Specifically, the peeling sheet is joined to the side of the peeling treatment surface on the coating film formed by the constituent body composed of the release sheet or the coating film of the adhesive composition obtained in the production process of the embodiment or the comparative example. The layer was layered and cured at 23 ° C, 50% RH for 7 days. Thus, an adhesive sheet composed of a structure of a release sheet (SP-PET3801) / an adhesive layer (thickness: 20 μm) / a release sheet (SP-PET 3811) was produced.

The obtained adhesive sheet was cut into a size of 80 mm × 80 mm, and the adhesive layer was coated on a polyester mesh (mesh fabric size 200), and the mass was weighed by a precision balance, minus The quality of the above-mentioned mesh fabric alone, thereby calculating the quality of only the adhesive. Set the quality at this time to M1.

Next, the adhesive coated on the above-mentioned polyester mesh fabric was immersed in ethyl acetate at room temperature (23 ° C) for 24 hours. After that, the adhesive is taken out and air-dried for 24 hours at a temperature of 23 ° C and a relative humidity of 50%. It was dried in an oven at 80 ° C for 12 hours. After drying, the mass was weighed by a precision balance, and the mass of the above-mentioned mesh fabric was subtracted, thereby calculating the quality of only the adhesive. Set the quality at this time to M2. The gel fraction (%) is represented by (M2/M1) × 100. The results are shown in Table 2 and Table 3.

[Test Example 2] (durability evaluation)

A polarizing plate with an adhesive layer obtained in the examples or the comparative examples was cut to prepare a sample having a size of 150 mm × 200 mm. The release sheet was peeled off from the sample and attached to an alkali-free glass (Eagle XG, manufactured by Corning Incorporated) via an exposed adhesive layer, and then autoclaved by KURIHARA Co., Ltd. was pressurized at 0.5 MPa and 50 ° C for 20 minutes. .

Thereafter, the mixture was placed in an environment of three durability conditions as follows, and after 50 hours, the presence or absence of warping or surface peeling was confirmed with a 10x magnification. The evaluation criteria are as follows. The results of the polarizing plates with the first adhesive layers of Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2, and the second adhesives were attached to Examples 1 to 13 and Comparative Examples 1 to 7. The results of the polarizing plates of the agent layer are shown in Table 3.

◎: No lift or surface peeling was confirmed.

○: The lift or surface peeling of a size of 0.5 mm or less was confirmed.

△: Lifting or surface peeling of a size exceeding 0.5 mm and 1.0 mm or less was confirmed.

×: Lifting or surface peeling of a size exceeding 1.0 mm was confirmed.

<endurance condition>

. Heat resistance: 85 ° C dry

. Damp heat: 60 ° C, relative humidity 90% RH

. HS: -35 ° C 30 minute thermal shock test at 70 ° C, 200 cycles

[Test Example 3] (evaluation of warpage resistance)

The polarizing plate with the adhesive layer obtained in the example or the comparative example was cut into a length of 200 mm and a width of 150 mm. The release sheet was peeled off from the polarizing plate with the adhesive layer, and the exposed adhesive layer was bonded to an alkali-free glass (manufactured by Corning Incorporated, trade name "Eagle-XG") having a length of 250 mm, a width of 175 mm, and a thickness of 0.5 mm. The central part of this is taken as a sample. The sample was allowed to stand at 85 ° C for 250 hours under a dry atmosphere. Thereafter, it was taken out in an environment of 25 ° C and 50% RH, and the polarizing plate was placed on the water platform with the side facing up, and the amount of warpage of each corner (4 points) of the sample from the stage (the distance between the corner and the table) was measured. ), the amount of warpage of each corner is totaled. According to the results, the warpage resistance was evaluated as follows. The results of the polarizing plates with the first adhesive layers of Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2, and the second adhesives were attached to Examples 1 to 13 and Comparative Examples 1 to 7. The results of the polarizing plates of the agent layer are shown in Table 3.

◎: The total amount of warpage is 10 mm or less

○: The total amount of warpage exceeds 10 mm and 15 mm or less

△: The total amount of warpage exceeds 15 mm and 20 mm or less

×: The total amount of warpage exceeds 20 mm

[Test Example 4] (Evaluation of heat resistance unevenness)

The polarizing plate with the adhesive layer obtained in the example or the comparative example was adjusted to a size of 200 mm × 150 mm by a cutting device (Super Cutter PN1-600 manufactured by Ogino Seisakusho Co., Ltd.). After peeling off the release sheet and attaching it to the alkali-free glass (Eagle XG, manufactured by Corning Incorporated) via the exposed adhesive layer, the autoclave manufactured by KURIHARA was manufactured at 0.5 MPa. Pressurize at 50 ° C for 20 minutes. Further, the bonding is performed on the front and back surfaces of the alkali-free glass so that the polarizing axis of the polarizing plate with the adhesive layer is in a state of being orthogonally polarized (polarizing axis: ∠45°, ∠135°). In this state, after standing in a dry environment at 80 ° C for 250 hours, it was allowed to stand in an environment of 23 ° C and 50% RH for 2 hours, and this was used as a sample, and the heat unevenness was evaluated by the method shown below. . The results of the polarizing plates with the first adhesive layers of Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2, and the second adhesives were attached to Examples 1 to 13 and Comparative Examples 1 to 7. The results of the polarizing plates of the agent layer are shown in Table 3.

<Evaluation method>

The above sample was placed on a flat illumination device (FLAT ILLUMINATOR) (manufactured by Raytronics Corp., HF-SL-A312LC, illuminance: 26,000 Lux, brightness: 10,000 cd), and a two-dimensional color luminance meter (KONICA MINOLTA, INC. Manufacturing, CA-2000) was photographed and converted into a luminance distribution image by an analysis software (manufactured by KONICA MINOLTA, INC., CA-S20w). The luminance distribution image of the obtained sample was evaluated based on the evaluation criteria shown in FIG. 4 and below.

◎: The brightness distribution is substantially uniform.

○: The brightness distribution of the four sides has some distortion.

△: The brightness distribution of the four sides has significant distortion.

×: The luminance distribution on the four sides is severely distorted.

[Test Example 5] (Adhesion measurement - reprocessing evaluation)

A sample of 25 mm wide and 100 mm long was cut out from the polarizing plate with an adhesive layer obtained in the examples or the comparative examples, and the peeling sheet was peeled off and attached to the alkali-free glass via the exposed adhesive layer (manufactured by Corning Incorporated). , Eagle XG) Thereafter, the autoclave manufactured by KURIHARA Co., Ltd. was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Thereafter, it was allowed to stand under the conditions of 23 ° C and 50% RH for 24 hours, and was measured under the conditions of a peeling speed of 300 mm/min and a glass angle of 180 degrees using a tensile tester (manufactured by ORIENTEC Co., Ltd., TENSILON). Adhesion (adhesion after 1 day; N/25mm). Conditions other than this were measured in accordance with JIS Z 0237:2009.

After standing for 14 days under conditions of 23 ° C and 50% RH, the adhesion (adhesion force after 14 days of attachment; N/25 mm) was measured in the same manner as above. In contrast, the polarizing plates with the second adhesive layers of Examples 1 to 13 and Comparative Examples 1 to 7 were placed under conditions of 50° C. and 50% RH for 2 days, and then measured in the same manner as above. Adhesion (adhesion after 2 days at 50 ° C; N / 25 mm).

The reprocessing property was evaluated based on the adhesion after 14 days from the attachment. The results are shown in Table 2.

◎: The adhesion after 14 days of attachment is 8.8N/25mm or less

○: Adhesive force after 14 days of attachment exceeds 8.8N/25mm, less than 10N/25mm

△: The adhesion after 14 days of attachment is 10N/25mm or more, less than 20N/25mm

×: The adhesion after 14 days of attachment is 20N/25mm or more

The results of the polarizing plates with the first adhesive layers of Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2, and the second adhesives were attached to Examples 1 to 13 and Comparative Examples 1 to 7. The results of the polarizing plates of the agent layer are shown in Table 3.

[Test Example 6] (Measurement of surface resistivity of the adhesive layer)

The polarizing plate with the adhesive layer obtained in the example or the comparative example was cut into a size of 50 mm × 50 mm, and the obtained sample was subjected to a temperature of 23 ° C, Place at a humidity of 50% RH for 24 hours. Thereafter, the release sheet was peeled off, and on the surface of the exposed adhesive layer, a surface resistivity (Ω was measured in accordance with JIS K6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Hiresta UP MCP-HT450 type). /sq). The results of the polarizing plates with the first adhesive layers of Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2, and the second adhesives were attached to Examples 1 to 13 and Comparative Examples 1 to 7. The results of the polarizing plates of the agent layer are shown in Table 3.

【Table 2】

As can be seen from Table 2 and Table 3, the polarizing plate with the adhesive layer obtained in the examples is excellent in durability and is not easily warped or deformed at high temperatures. It is easy to produce uneven heat. Further, the polarizing plate-based pressure-sensitive adhesive layer having an adhesive layer obtained in the examples has a low surface resistivity and a small adverse effect on a liquid crystal cell or the like. Further, the polarizing plates with the adhesive layers obtained in Examples 1 to 12 were also excellent in reworkability.

[Industrial availability]

The polarizing plate with an adhesive layer of the present invention is suitable for bonding a liquid crystal cell having a transparent conductive film to a polarizing plate and a liquid crystal cell, particularly a bonding surface.

10A‧‧‧Polarizer with adhesive layer

1‧‧‧Adhesive layer

2A‧‧‧Polar plate

21‧‧‧Polar photons

22‧‧‧1st protective layer

23‧‧‧2nd protective layer

Claims (14)

A polarizing plate with an adhesive layer, comprising: a polarizer; a first protective layer laminated on one surface side of the polarizer; a second protective layer laminated on the other side of the polarizer; and a layer deposited on the first The adhesive layer on the side opposite to the surface on the polarizer side of the protective layer, and the polarizing plate with the adhesive layer is characterized in that the adhesive layer is obtained from the adhesive composition and the gel fraction is 60 to 89% of an adhesive composition comprising: (meth) acrylate copolymer (A) containing an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and The hydroxy monomer (a3), as a monomer unit constituting the polymer, has 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 crosslinking agent ( B) The second protective layer is composed of a cycloolefin resin or triacetyl cellulose, the polarizer has a thickness of 1 to 20 μm, the second protective layer has a thickness of 5 to 30 μm, and the thickness of the second protective layer. The ratio of the thickness of the aforementioned polarizer is 1.0 to 5.0. The polarizing plate with an adhesive layer according to claim 1, wherein the first protective layer has a thickness of 5 to 120 μm, and the ratio of the thickness of the first protective layer to the thickness of the polarizer is 1.0. ~6.0. The polarizing plate with an adhesive layer as described in claim 1, wherein the first protective layer is made of triacetyl cellulose. The polarizing plate with an adhesive layer as described in claim 1, wherein the alicyclic structure of the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure. The polarizing plate with an adhesive layer as described in claim 1, wherein the adhesive composition further contains an epoxy group-containing decane coupling agent (C1). The polarizing plate with an adhesive layer as described in claim 1, wherein the adhesive composition further contains a mercapto-containing decane coupling agent (C2). The polarizing plate with an adhesive layer as described in claim 1, wherein the adhesive composition further contains an antistatic agent (D). The polarizing plate with an adhesive layer as described in claim 7, wherein the antistatic agent (D) is an ionic compound which is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion. . The polarizing plate with an adhesive layer as described in claim 1, wherein the isocyanate crosslinking agent (B) is a compound having an aromatic ring. The polarizing plate with an adhesive layer as described in claim 1, wherein the (meth) acrylate copolymer (A) does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. The polarizing plate with an adhesive layer as described in claim 1, wherein the (meth) acrylate copolymer (A) contains 1 to 40% by mass of the aforementioned alicyclic structure-containing monomer (a1) As a monomer unit constituting the polymer. The polarizing plate with an adhesive layer according to the first aspect of the invention, wherein the (meth) acrylate copolymer (A) contains 1 to 40% by mass of the aromatic ring-containing monomer (a2) as a constituent. A monomer unit of the polymer. The polarizing plate with an adhesive layer as described in claim 1, wherein the (meth) acrylate copolymer (A) contains 0.5 to 10% by mass of the hydroxyl group-containing monomer (a3) as a constituent. Monomer unit of polymer. The polarizing plate with an adhesive layer as described in claim 1, wherein the surface resistivity of the adhesive layer is 1.0 × 10 ¹² Ω/sq or less.