TWI698665B - Polarizing plate with adhesive layer - Google Patents

Abstract

The present invention provides a polarizing plate with an adhesive layer that has excellent durability, a display panel that is not prone to warpage, and is not prone to heat unevenness even when the polarizer is a film. A polarizing plate (10A) with an adhesive layer, comprising: a polarizer (21); a first protective layer (22) laminated on one side of the polarizer (21); another layer on the polarizer (21) The second protective layer (23) on one side; and the adhesive layer (1) on the side opposite to the polarizer (21) side of the second protective layer (23), and the adhesive layer In the polarizing plate (10A), the adhesive layer (1) is composed of an adhesive with a gel fraction of 60 to 89% obtained from an adhesive composition, and the aforementioned adhesive composition contains: (meth)acrylate copolymer Substance (A) contains alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2) and hydroxyl-containing monomer (a3) as monomer units constituting the polymer, with a hydroxyl value of 5-20mgKOH/g, The acid value is less than 5mgKOH/g, and the weight average molecular weight is 1.3 million to 3 million; and isocyanate-based crosslinking agent (B), the second protective layer (23) is composed of cycloolefin-based resin or triacetyl cellulose, polarized The thickness of (21) is 1-20 μm, the thickness of the second protective layer (23) is 5-30 μm, and the ratio of the thickness of the second protective layer (23) to the thickness of the polarizer (21) is 1.0-5.0.

Description

Polarizing plate with adhesive layer

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

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 mainly include resistive film type, capacitive type, optical type and ultrasonic type. The resistive film type includes analog resistive film type and matrix resistive film type; the capacitive type includes surface type and projection type.

Projected capacitive types are widely used in touch panels of mobile electronic devices such as smartphones or tablet computers that have attracted much attention recently. As a projection type capacitive touch panel of related mobile electronic devices, for example, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, a transparent Conductive film (ITO) and tempered glass protection board.

As an optical component constituting the above-mentioned liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell is usually configured with the alignment layer of the two transparent electrode substrates forming the alignment layer as the inner side, a predetermined interval is formed by spacers, and the surroundings are sealed and the liquid crystal material is sandwiched between the two transparent electrode substrates. Usually, the outer sides of the two transparent electrode substrates in the liquid crystal cell are respectively bonded to the polarizing plate by an adhesive.

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

【Prior Technical Literature】 【Patent Literature】

Patent Document 1: Japanese Patent Application Publication No. 2009-242786

Here, with the recent demand for thinner mobile electronic devices, thinner polarizers are also required. However, the shrinkage rate of the polarizing plate of the film due to heat is high. In conventional adhesives such as Patent Document 1, there is a concern that the display panel may warp, or warp or surface under high temperature or humid conditions. Problems such as peeling. In addition, in order to improve the durability of the adhesive, when a monomer with a high glass transition point (Tg) is used as a component of a (meth)acrylic polymer to copolymerize, large shrinkage stress will be generated under high temperature conditions. , The warpage of the display panel increases. It is also pointed out that due to the stress caused by the thermal shrinkage of the polarizing plate, the problem of light leakage (so-called thermal unevenness) caused by the deviation of the optical axis of the polarizing plate will occur.

The present invention was completed in view of this actual situation, and its purpose is to provide a polarizer with an adhesive layer that has excellent durability, a display panel that is not prone to warpage, and is not prone to heat unevenness even when the polarizer is a film. board.

In order to achieve the above object, first of all, the present invention provides a polarizing plate with an adhesive layer, which includes: a polarizer; a first protective layer laminated on one side of the polarizer; and a first protective layer laminated on the other side of the polarizer. A second protective layer; and an adhesive layer laminated on the side of the second protective layer opposite to the side of the polarizer, in the polarizing plate with the adhesive layer, the adhesive layer is composed of adhesive The adhesive composition is composed of an adhesive with a gel fraction of 60% to 89%. The aforementioned adhesive composition contains: (meth)acrylate copolymer (A) containing alicyclic structure monomer (a1), aromatic The cyclic monomer (a2) and the hydroxyl-containing monomer (a3) are the monomer units that constitute the polymer, with 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 million to 3 million; And isocyanate-based crosslinking agent (B), the second protective layer is made of cycloolefin resin or triacetyl cellulose, the thickness of the polarizer is 1-20 μm, and the thickness of the second protective layer is 5-30 μm, The ratio of the thickness of the second protective layer to the thickness of the polarizer is 1.0 to 5.0 (Invention 1).

According to the above-mentioned invention (Invention 1) of the polarizing plate with an adhesive layer, the polarizing plate has been thinner than conventional products. Nevertheless, when the adhesive layer-attached polarizing plate is applied to a display panel, the adhesive layer-attached polarizing plate has excellent durability, and the display panel is not prone to warpage and is not prone to heat unevenness.

In the above invention (Invention 1), it is preferable that 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 1.0 to 6.0 (Invention 2).

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

In the above inventions (Inventions 1 to 3), it is preferable that the alicyclic structure of the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure (Invention 4).

In the above inventions (Inventions 1 to 4), the adhesive composition preferably further contains an epoxy group-containing silane coupling agent (C1) (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the adhesive composition further contains a mercapto group-containing silane coupling agent (C2) (Invention 6).

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

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

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

In the above inventions (Inventions 1 to 9), the (meth)acrylate copolymer (A) preferably does not contain a carboxyl group-containing monomer as the monomer unit constituting the copolymer (Invention 10).

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

In the above invention (Inventions 1 to 11), the (meth)acrylate copolymer (A) contains 1 to 40% by mass of the aromatic ring-containing monomer (a2) as the monomer unit constituting the copolymer Better (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-containing monomer (a3) It is preferable as a monomer unit constituting the copolymer (Invention 13).

In the above inventions (Inventions 1 to 13), the surface resistivity of the adhesive layer is preferably 1.0×10 ¹² Ω/sq or less (Invention 14).

According to the polarizing plate with the adhesive layer of the present invention, even when the polarizing plate is a film, it has excellent durability, the display panel is not prone to warpage, and is not prone to heat unevenness.

10A, 10B‧‧‧Polarizing plate with adhesive layer

1‧‧‧Adhesive layer

2A‧‧‧Polarizer

2B‧‧‧Composite Polarizing Plate

21‧‧‧Polarized photons

22‧‧‧The first protective layer

23‧‧‧Second protection layer

24‧‧‧The first phase difference plate

241‧‧‧The first acrylic resin layer

242‧‧‧Phase Difference Expression Layer

243‧‧‧The second acrylic resin layer

25‧‧‧The second phase difference plate (the second protective layer)

26‧‧‧Second adhesive layer

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

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

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

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

Fig. 4 is a graph (color) showing the evaluation criteria of the heat non-uniformity 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; a first protection layered on one side (upper side in FIG. 1) of the polarizer 21 Layer 22; the second protective layer 23 laminated on the other side of the polarizer 21 (the lower side in FIG. 1;); and the second protective layer 23 laminated on the side opposite to the side of the polarizer 21 (Figure 1 is the lower side) 的胶层1。 Adhesive layer 1. In this embodiment, a laminate of the first protective layer 22, the polarizer 21, and the second protective layer 23 constitutes the polarizing plate 2A. In addition, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the polarizing plate 2A side until the polarizing plate 10A with the adhesive layer is used.

The adhesive layer 1 is composed of an adhesive 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-containing monomer (a3) as the monomer units constituting the polymer, and the hydroxyl value It is 5~20mgKOH/g, the acid value is less than 5mgKOH/g, and the weight average molecular weight is 1.3 million to 3 million; and isocyanate-based crosslinking agent (B). In addition, in this specification, (meth)acrylate means both acrylate and methacrylate. Other similar terms are also the same.

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

In the polarizing plate 10A with an adhesive layer that satisfies the above-mentioned requirements, the polarizing plate 2A has been thinned compared to conventional products, and the display panel can be thinned. Nevertheless, when the adhesive layer-attached polarizing plate 10A is applied to a display panel, the adhesive layer-attached polarizing plate 10A has excellent durability, and it can be used under high temperature conditions, damp heat conditions, or thermal shock. Suppresses warping or surface peeling. In addition, the display panel using the above-mentioned polarizing plate 10A with the adhesive layer is not prone to warpage under high temperature conditions, and is not prone to heat unevenness.

1. Adhesive layer

(1) Physical properties

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

If the hydroxyl value of the (meth)acrylate copolymer (A) is less than 5 mgKOH/g, there are too few crosslinking points and the cohesive force decreases, and the resulting adhesive cannot exhibit excellent durability. In addition, if the hydroxyl value of the (meth)acrylate copolymer (A) exceeds 20 mgKOH/g, there will be too many crosslinking points, the resulting adhesive will not be soft, and the stress relaxation properties will decrease. , The display panel warps or heat unevenness occurs.

From the above viewpoint, the lower limit of the hydroxyl value of the (meth)acrylate copolymer (A) is preferably 8 mgKOH/g or more, and particularly preferably 10 mgKOH/g or more. In addition, 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 object to which the adhesive is applied is an acid that may cause problems, such as tin-doped indium oxide ( When transparent conductive films such as ITO) or metal films, etc., it is also possible to suppress such defects caused by acid. In particular, when the attachment object is a transparent conductive film, the corrosion of the transparent conductive film or the change in the resistance value of the transparent conductive film can be suppressed.

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

Here, the hydroxyl value and acid value in this specification are basically the theoretical values derived from the blending ratio of the (meth)acrylate copolymer (A). If the theoretical values cannot be derived, they shall be measured based on JIS K0070 Value.

If the weight average molecular weight of the (meth)acrylate copolymer (A) is less than 1.3 million, the durability of the adhesive layer 1 of this embodiment will deteriorate. In addition, if the weight average molecular weight of the (meth)acrylate copolymer (A) exceeds 3 million, the stress relaxation properties of the adhesive layer 1 of the present embodiment are reduced, and under high temperature conditions, the display panel may warp or heat Uneven.

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

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

In addition, if the gel fraction of the adhesive constituting the adhesive layer 1 is less than 60%, the durability of the adhesive deteriorates. On the other hand, if the gel fraction of the adhesive constituting the adhesive layer 1 exceeds 89%, the stress relaxation of the adhesive layer 1 decreases, and under high temperature conditions, the display panel warps or heat unevenness occurs.

From the above viewpoint, the lower limit of the gel fraction of the adhesive constituting the adhesive layer 1 is preferably 65% or more, and particularly preferably 70% or more. In addition, the upper limit of the gel fraction of the adhesive constituting the adhesive layer 1 is 85% or less, which is relatively Good, 78% or less is particularly good. In addition, the measuring method of the gel fraction of an adhesive is as shown in the test example mentioned later.

The haze value (value measured in accordance with JIS K7136: 2000) of the adhesive layer 1 in this embodiment is preferably 2% or less, particularly preferably 1% or less. When the haze value is 2% or less, the transparency is very high and it is suitable for optical applications.

(2) (Meth) acrylate copolymer (A)

The (meth)acrylate copolymer (A) in this embodiment contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl-containing monomer (a3) as constituting the copolymer The monomer unit. Among these monomers, especially by containing the alicyclic structure-containing monomer (a1) and aromatic ring-containing monomer (a2), the resulting adhesive can have appropriate cohesion and stress relaxation properties, and is The adhesion of the polarizing plate or the transparent conductive film is improved, and therefore, when used in a display panel, it can exhibit excellent durability, warpage suppression, and heat unevenness.

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

The (meth)acrylate copolymer (A) contains alkyl (meth)acrylate alkyl having 1 to 20 carbon atoms as the monomer unit constituting the copolymer, which can express better adhesion . Examples of alkyl (meth)acrylates having an alkyl group with 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, ( N-butyl meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, (meth) 2-ethylhexyl acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, ( Cetyl meth)acrylate, stearyl (meth)acrylate, etc. Among them, from the viewpoint of further improving adhesiveness, (meth)acrylates having an alkyl group of 1 to 8 carbon atoms are preferred, n-butyl (meth)acrylate or 2-ethyl (meth)acrylate Base hexyl ester is particularly preferred. In addition, these can be used alone or in combination of two or more kinds.

The (meth)acrylate copolymer (A) preferably contains an alkyl (meth)acrylate having 1 to 20 carbon atoms and containing 40 to 97.5 mass% of alkyl groups as the monomer unit constituting the copolymer It is particularly preferable to contain 55-94% by mass, and more preferably 65-83% by mass. If the alkyl (meth)acrylate is contained at 40% by mass or more, the (meth)acrylate copolymer (A) can be imparted with suitable adhesiveness. In addition, by setting the alkyl (meth)acrylate to 97.5% by mass or less, a required amount of other monomer components can be introduced into the (meth)acrylate copolymer (A).

The carbocyclic ring of the alicyclic structure in the alicyclic structure-containing monomer (a1) may be a saturated structure or a partially unsaturated bond. In addition, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as bicyclic and tricyclic. From the viewpoint of setting the distance between the obtained (meth)acrylate copolymer (A) to be appropriate and imparting stress relaxation to the adhesive, the above-mentioned alicyclic structure is a polycyclic alicyclic structure (Polycyclic structure) is preferred. Further considering the compatibility of the (meth)acrylate copolymer (A) with other components, it is particularly preferred that the above-mentioned polycyclic structure is bicyclic to tetracyclic. In addition, from the viewpoint of imparting stress relaxation properties as described above, the number of carbon atoms in the alicyclic structure (It refers to the total number of carbon atoms in the part forming the ring, and when a plurality of rings exist independently, it refers to the total number of carbon atoms.) Generally, 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, as with 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 containing the following skeletons, cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornane) skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, ring Nonane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloolefin skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, Cubarane skeleton, basketane skeleton, room alkane skeleton, spiro ring skeleton, etc., including dicyclopentadiene skeleton (the number of carbon atoms of the alicyclic structure: 10) and adamantane skeleton, which can exhibit 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 preferable, and the one containing the isobornyl skeleton is particularly preferable.

As the above-mentioned alicyclic structure-containing monomer (a1), (meth)acrylate monomers containing the above-mentioned skeleton are preferred. Specifically, cyclohexyl (meth)acrylate and (meth)acrylic acid are mentioned. Dicyclopentyl ester, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, etc. , Dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate or isobornyl (meth)acrylate which can exert relatively excellent durability are preferred, and isobornyl (meth)acrylate is particularly preferred Esters, these can be used alone or in combination of two or more kinds.

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

As the aromatic ring-containing monomer (a2), (meth)acrylate having an aromatic ring is preferred. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, and a sulphur ring. Among them, a benzene ring is preferred.

As the aromatic ring-containing monomer (a2), for example, phenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, Phenoxyethyl (meth)acrylate, phenoxybutyl (meth)acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide Alkyl-modified cresol (meth)acrylate, ethylene oxide (EO)-modified nonylphenol (meth)acrylate, etc., among which, from the viewpoint of improving cohesion, 2-benzene (meth)acrylate Group ethyl is preferred. These can be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) preferably contains 1-40% by mass of the aromatic ring-containing monomer (a2) as the monomer unit constituting the copolymer, and more preferably contains 2-30% by mass. It is particularly preferable to contain 3 to 25% by mass, and more preferably 12 to 22% by mass. By setting the content of the aromatic ring-containing monomer (a2) within the above-mentioned range, the resulting adhesive can exhibit excellent durability, warpage suppression properties, and heat unevenness.

The (meth)acrylate copolymer (A) contains a hydroxyl-containing monomer (a3) As a monomer unit constituting the copolymer. The hydroxyl group has high reactivity with the isocyanate group of the isocyanate-based crosslinking agent (B), and by their reaction, the (meth)acrylate copolymer (A) is crosslinked by the isocyanate-based crosslinking agent (B). Due to this crosslinked structure, the obtained adhesive has excellent durability.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth) Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., among them, isocyanate-based 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 can be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) preferably contains 0.5-10% by mass of the hydroxyl-containing monomer (a3) as the monomer unit constituting the copolymer, and particularly preferably contains 1 to 5% by mass, and further Preferably, it contains 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 easily fall within the above range, and the excellent durability can be effectively exhibited. Warpage suppression and heat unevenness.

In order to keep the acid value within the aforementioned range, the (meth)acrylate copolymer (A) preferably does not contain a carboxyl group-containing monomer as the monomer unit constituting the copolymer. Even if it contains a carboxyl group-containing monomer, it also contains A content of 0.5% by mass or less is preferable, and a content of 0.1% by mass or less is particularly preferable.

The (meth)acrylate copolymer (A) may contain other monomers than the aforementioned monomers as monomer units constituting the copolymer. So as not to hinder The reaction between the hydroxyl group of the hydroxyl-containing monomer (a3) and the isocyanate-based crosslinking agent (B) is to use a monomer that does not contain a functional group reactive with the isocyanate-based crosslinking agent (B) as the other monomer. good.

Examples of such other monomers include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; acrylamide, methyl methacrylate, etc. Non-crosslinkable acrylamide such as acrylamide; N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. Crosslinkable tertiary amino (meth)acrylate; vinyl acetate, etc. These can be used alone or in combination of two or more.

The polymerization aspect 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. In addition, the adhesive composition P may also contain the following (meth)acrylate polymer, wherein the (meth)acrylate polymer does not contain the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer ( a2) or a hydroxyl-containing monomer (a3) as the constituent monomer unit.

(3) Isocyanate-based crosslinking agent (B)

The isocyanate-based crosslinking agent (B) has the advantage of excellent reactivity with the hydroxyl group (derived from the hydroxyl-containing monomer (a3)) of the (meth)acrylate copolymer (A).

The isocyanate-based crosslinking agent (B) contains at least a polyisocyanate compound. As the polyisocyanate compound, for example, aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; isofluorine Alicyclic polyisocyanates such as ketone diisocyanate, hydrogenated diphenylmethane diisocyanate, etc., in addition to these, there are also biuret, isocyanurate, and ethylene glycol, propylene glycol, Adducts of reactants containing low-molecular-weight active hydrogen compounds such as neopentyl glycol, trimethylolpropane, and castor oil (the above are sometimes collectively referred to as "modified products"), etc. Among them, 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 relatively It is preferably an alkylene chain, and particularly preferably an alkylene chain having 1 to 4 carbon atoms) polyisocyanate having an isocyanate group bonded to an aromatic ring, or a modified form thereof. Specifically, xylylene diisocyanate or a modified product thereof is more preferable, and xylylene diisocyanate modified with trimethylolpropane is the most preferable. The above-mentioned isocyanate-based crosslinking agent (B) may be used alone or in combination of two or more.

The content of the isocyanate-based crosslinking agent (B) in the adhesive composition P is preferably 0.01-10 parts by mass, and 0.05-5 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A) Particularly preferred, 0.1 to 0.4 parts by mass is further preferred. By setting the content of the isocyanate-based crosslinking agent (B) within the above-mentioned range, the gel fraction of the adhesive easily falls within the above-mentioned range, and it is easy to obtain excellent durability, warpage suppression properties, and heat unevenness The adhesive.

(4) Silane coupling agent (C)

In the adhesive composition P, in addition to the above-mentioned (meth)acrylate copolymer (A) and isocyanate-based crosslinking agent (B), it is preferable to further contain a silane coupling agent (C), since it imparts the resulting adhesive From the viewpoint of excellent durability of the agent, it is particularly preferable to contain an epoxy-containing silane coupling agent (C1) and/or a mercapto-containing silane coupling agent (C2), and it is more preferable to contain an epoxy-containing silane coupling agent (C1). ) And containing Mercaptosilane coupling agent (C2) both.

As an epoxy-containing silane coupling agent (C1), an organosilicon compound having at least one epoxy group (organic group containing epoxy group) and at least one alkoxysilyl group in the molecule, and an adhesive component Those with good compatibility and light transmittance, such as substantially transparent ones.

Specific examples of the epoxy group-containing silane coupling agent (C1) include 3-glycidol such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane Oxypropyl trialkoxy silane; 3-glycidoxy propyl 3-glycidoxy propyl methyl diethoxy silane, 3-glycidoxy propyl methyl dimethoxy silane, etc. Alkyl dialkoxysilane; methyl tris(glycidyl) silane; 2-(3,4-epoxycyclohexyl) ethyl trimethoxy silane, 2-(3,4-epoxycyclohexyl) ) 2-(3,4-epoxycyclohexyl) ethyl trialkoxysilane, such as ethyl triethoxy silane, etc. Among them, from the standpoint of improving durability, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldi Ethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are preferred, and 3-glycidoxypropyltrimethoxysilane is particularly preferred. These can be used alone or in combination of two or more.

As a suitable mercapto-containing silane coupling agent (C2), it is an organosilicon compound with at least one mercapto group (organic group containing mercapto group) and at least one alkoxysilyl group in the molecule, and has good compatibility with the adhesive components and Those with translucency, for example, those that are substantially transparent.

Specific examples of the mercapto group-containing silane coupling agent (C2) include: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercapto Mercapto-containing low-molecular-weight silane coupling agents such as propyldimethoxymethylsilane; and mercapto-containing silane compounds (such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercapto Propyl dimethoxymethyl silane, etc.) and alkyl-containing silane compounds (such as methyl triethoxy silane, ethyl triethoxy silane, methyl trimethoxy silane, ethyl trimethoxy silane, etc.) The co-condensate and other mercapto-containing oligomer type silane coupling agent. Among them, from the viewpoint of both durability and reprocessing properties, the mercapto group-containing oligomer type silane coupling agent is preferred, particularly preferably a co-condensate of mercapto group-containing silane compound and alkyl-containing silane compound, and more preferably The co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane. These can be used alone or in combination of two or more.

As the silane coupling agent (C), in addition to the epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), for example, acryl-based silane coupling agent, hydroxy-based silane coupling agent can be used in combination as needed. Mixture, carboxyl-based silane coupling agent, amine-based silane coupling agent, amide-based silane coupling agent, isocyanate-based silane coupling agent, etc.

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

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

(5) Antistatic agent (D)

The adhesive composition P preferably further contains an antistatic agent (D). The peeling sheet or polarizing plate laminated on the adhesive layer 1 is usually made of plastic material, so it has high electrical insulation. For example, static electricity is likely to be generated when peeling the peeling sheet. In a state where the static electricity generated in this way remains, when the polarizing plate is attached to the liquid crystal cell, the alignment of the liquid crystal molecules may be disturbed. In addition, the presence of static electricity may cause problems such as attracting flying dust and dirt. Therefore, since the adhesive composition P contains the antistatic agent (D), the resulting adhesive (adhesive layer 1) can exhibit antistatic properties, thereby eliminating the above-mentioned problems.

The antistatic agent (D) may be any one that can impart antistatic properties to the adhesive obtained, and examples thereof include ionic compounds and nonionic compounds. Among them, ionic compounds are preferred. The ionic compound may be liquid or solid at room temperature, but from the viewpoint of easily exhibiting stable antistatic properties even when exposed to durable conditions, a solid at room temperature is preferred. Here, the ionic compound in this specification refers to a compound composed mainly of cations and anions and bonded by electrostatic attraction.

As the ionic compound, nitrogen-containing onium salt, sulfur-containing onium salt, phosphonium-containing onium salt, alkali metal salt, and alkaline earth metal salt are preferred. From the viewpoint of excellent durability of the resulting adhesive, particularly preferred Nitrogen-containing onium salt. Nitrogen-containing onium salts are preferably ionic compounds composed of nitrogen-containing heterocyclic cations and counter anions, particularly preferably ionic compounds composed of nitrogen-containing heterocyclic cations and halogenated phosphoric acid anions, and more preferably at room temperature The following is solid and is composed of nitrogen-containing heterocyclic cations and halogenated Ionic compound composed of phosphate anion. According to the ionic compound that is solid at room temperature and composed of nitrogen-containing heterocyclic cations and halogenated phosphoric acid anions, it is possible to have both antistatic properties and durability.

As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, an indole ring, etc. are preferable, and among them, a pyridine ring is preferable. In addition, as the halogen of the halogenated phosphoric acid anion, fluorine, chlorine, bromine, etc. are preferable, and among them, fluorine is preferable.

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, and N-octyl 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- Hexadecyl-4-methylpyridinium hexafluorophosphate, etc. 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 agent (D) may be used alone or in combination of two or more.

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

(6) Various additives

Various additives commonly used in acrylic adhesives can be added to the adhesive composition P as needed, such as dispersing agents (for example, alkylene glycol dialkyl ether), tackifiers, antioxidants, and ultraviolet absorbers. Agents, light stabilizers, softeners, fillers, refractive index modifiers, etc. In addition, the adhesive composition P refers to a mixture of various components remaining in the adhesive layer as it is or in a reacted state, and is removed during a drying process, such as the polymerization solvent or diluting solvent described later It is not included in the adhesive composition P.

(7) Adhesive composition and manufacturing method of adhesive

The adhesive composition P can be manufactured by the following method: manufacturing a (meth)acrylate copolymer (A), and combining the obtained (meth)acrylate copolymer (A) with an isocyanate-based crosslinking agent (B), The silane coupling agent (C), antistatic agent (D) and additives are mixed as needed to manufacture.

The (meth)acrylate copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a normal radical polymerization method. The polymerization of the (meth)acrylate copolymer (A) can be performed by a solution polymerization method or the like using a polymerization initiator as necessary. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc. are mentioned, for example, You may use 2 or more types together.

Examples of the polymerization initiator include azo compounds, organic peroxides, and the like, and two or more of them may be used in combination. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane Alkane 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- Hydroxymethylpropane Nitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and the like.

Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate,- Di-(2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecyl, tert-butyl peroxypivalate, (3,5,5-trimethylhexyl) Peroxide, dipropylene peroxide, diacetyl peroxide, etc.

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

After the (meth)acrylate copolymer (A) is obtained, the isocyanate-based crosslinking agent (B) is added to the solution of the (meth)acrylate copolymer (A), and the silane coupling agent (C), The antistatic agent (D), additives, diluting solvent, etc. are mixed thoroughly to obtain an adhesive composition P (coating solution) diluted with the solvent.

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

The concentration and viscosity of the coating solution prepared in this way are not particularly limited as long as they are within the coatable range, and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P is diluted to 10-40% by mass. In addition, when obtaining the coating solution, the addition of a diluting solvent is not a necessary condition, as long as the viscosity is The viscosity of the adhesive composition P is a viscosity that can be applied, and the dilution solvent may not be added. In this case, the adhesive composition P becomes a coating solution in which the polymerization solvent of the (meth)acrylate copolymer (A) is directly used as the dilution solvent.

The adhesive constituting the adhesive layer 1 of the present embodiment is obtained from the adhesive composition P, specifically, the adhesive composition P is cross-linked. The adhesive composition P can be cross-linked by heat treatment. In addition, the drying treatment at the time of volatilizing the diluent solvent of the adhesive composition P can also be used as the heating treatment.

When performing the heat treatment, the heating temperature is preferably 50 to 150°C, particularly preferably 70 to 120°C. In addition, the heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes. After the heat treatment, a curing period of about 1 to 2 weeks at room temperature (for example, 23°C, 50%RH) can be set as needed. When the curing period is required, an adhesive layer with predetermined physical properties is formed after the curing period, and when the curing period is not required, the aforementioned adhesive layer is formed after the heat treatment is completed.

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

(8) The thickness of the adhesive layer

The thickness of the adhesive layer 1 is usually 5 to 100 μm, preferably in the range of 10 to 60 μm. However, from the viewpoint of excellent durability, warpage suppression properties, and heat non-uniformity exerted by the adhesive layer 1, 10~50μm is preferred, 15~30μm is particularly preferred.

2. Polarizing plate

(1) Structure

As shown in FIG. 1, the polarizing plate 2A of this embodiment has a structure in which a first protective layer 22, a polarizer 21, and a second protective layer 23 are laminated in this order. By having this structure, the polarizing plate 2A has excellent mechanical strength and chemical resistance. In addition, although not shown, an adhesive layer may be sandwiched between the polarizer 21 and the first protective layer 22 and/or between the polarizer 21 and the second protective layer 23.

(2) Polarized photons

The polarizer 21 is preferably composed of a polyvinyl alcohol resin film in which the 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 polyvinyl acetate-based resins, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, vinyl acetate and other monomer copolymers copolymerizable therewith, etc. are also exemplified. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.

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

The above-mentioned polarizer 21 is preferably produced by the following processes. The aforementioned processes include: uniaxially stretching the polyvinyl alcohol resin film; dyeing and adsorbing the polyvinyl alcohol resin film with dichroic pigments The dichroic dye; and the polyvinyl alcohol resin film on which the dichroic dye is adsorbed is treated with an aqueous solution of boric acid.

Uniaxial stretching can be performed before dyeing with dichroic pigments, or simultaneously with the process of dyeing with dichroic pigments, or after dyeing with dichroic pigments. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before the boric acid treatment or may be performed during the boric acid treatment. Of course, it is also possible to perform uniaxial extension in these plural stages. When performing uniaxial stretching, it can be uniaxially extended between rollers with different peripheral speeds, or it can be uniaxially extended by using a heated roller. In addition, it may be dry stretching in the atmosphere, or wet stretching in a state swollen with a solvent. The stretching ratio is usually about 4 to 8 times.

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

When iodine is used as a dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide for dyeing is generally adopted. 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 20-40°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 a dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid aqueous solution. The content of boric acid in the boric acid aqueous solution is usually about 2 to 15 parts by mass per 100 parts by mass of water, and preferably about 5 to 12 parts by mass. When using iodine as a dichroic pigment, The boric acid aqueous solution preferably contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is usually about 2 to 20 parts by mass per 100 parts by mass of water, and preferably 5 to 15 parts by mass. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50°C or higher, preferably 50 to 85°C.

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

The thickness of the polarizer 21 of the present embodiment is 1 to 20 μm, which is a thinner film than a normal polarizer. If the thickness of the polarizer 21 is less than 1 μm, sufficient polarization performance cannot be exhibited. In addition, if the thickness of the polarizer 21 exceeds 20 μm, the warpage suppression effect and the heat unevenness effect of the adhesive layer 1 are exceeded, and warpage or thermal unevenness occurs in the display panel. From this viewpoint, 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 composed of a transparent resin film. The transparent resin film constituting the first protective layer 22 may be an unstretched film, or a uniaxially or biaxially stretched film.

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

As the amorphous polyolefin resin used for the first protective layer 22, cycloolefin resin is preferable. Examples of cycloolefin-based resins include, for example, cyclopentadiene and olefins, which are obtained by Diels-Alder reaction of norbornene or its derivatives as monomers, subjected to ring-opening translocation polymerization, followed by Resin obtained by hydrogenation; Dicyclopentadiene and olefins or methacrylates are obtained by Diels-Alder reaction of tetracyclododecene or its derivatives as monomers for ring-opening translocation After the polymerization, the resin obtained by hydrogenation; using two or more selected from norbornene, tetracyclododecene and derivatives thereof, and other cyclic polyolefin monomers, the same is used for ring opening Resins obtained by hydrogenation after translocation polymerization; resins obtained by addition copolymerization of norbornene, tetracyclododecene or their derivatives and aromatic compounds with vinyl groups. Examples of commercially available amorphous polyolefin resins include "ARTON" of JSR CORPORATION, "ZEONEX" and "ZEONOR" of Zeon Corporation, "APO" and "APEL" of Mitsui Chemicals, Inc., and the like. When the amorphous polyolefin-based resin is formed into a film as a film, a known method such as a solvent casting method and a melt extrusion method can be suitably used to form a film.

As the cellulose resin, a resin in which at least a part of the hydroxyl groups in the cellulose is esterified with acetic acid may be a mixed ester in which a part is esterified with acetic acid and a part is esterified with another. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetyl cellulose resin. Specific examples of acetyl cellulose resins include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. As a thin layer made of such acetyl cellulose resin Commercial products of the film include, for example, "Fujitac TD80", "Fujitac TD80UF" and "Fujitac TD80UZ" manufactured by FUJIFILM Corporation; "KC8UX2M", "KC2UA" and "Fujitac TD80UZ" manufactured by Konica Minolta Opto Products Co., Ltd. KC8UY" etc.

It is also possible to use a cellulose-based resin film provided with an optical compensation function. As the optical compensation film, for example, a film containing a compound having a retardation adjustment function in a cellulose resin; a film having a retardation adjustment function coated on the surface of a cellulose resin; and A film obtained by uniaxially or biaxially stretching a cellulose resin. Examples of commercially available cellulose-based resin optical compensation films include: "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 acetyl cellulose resin, and more preferably composed of triacetyl cellulose. The display panel obtained by forming the first protective layer 22 of triacetyl cellulose is not prone to warpage under high temperature conditions, and is not prone to heat 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 even more preferably 10 to 30 μm. If the thickness of the first protective layer 22 is 5 μm or more, the polarizer 21 can be sufficiently protected. In addition, if the thickness of the first protective layer 22 is 120 μm or less, the warpage suppression effect and the heat unevenness effect of the adhesive layer 1 can be sufficiently exhibited.

Furthermore, the thickness of the first protective layer 22 is relative to that of the polarizer 21 The thickness ratio is preferably 1.0 to 6.0, 1.4 to 4.0 is particularly preferable, and 1.6 to 3.8 is even more preferable. By setting the ratio within the above-mentioned range, the warpage suppression effect and the heat unevenness effect of the adhesive layer 1 can be fully exhibited.

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

The second protective layer 23 adjacent to the adhesive layer 1 is made of cycloolefin resin or triacetyl cellulose excellent in optical isotropy. Thereby, the obtained polarizing plate 2A can suppress the degradation of optical performance to the minimum. In addition, from the viewpoint of achieving thin film while maintaining optical performance, it is more preferable that the second protective layer 23 is composed of a cycloolefin resin.

As the cycloolefin resin constituting the second protective layer 23, the cycloolefin resin exemplified by the first protective layer 22 can be used. Among them, dicyclopentadiene-based resins are preferred. As a commercially available product of this cycloolefin resin, "ZEONOR" of Zeon Corporation is particularly preferred.

As a commercially available product of triacetyl cellulose constituting the second protective layer 23, "KC2UA" manufactured by Konica Minolta Opto Products Co., Ltd. is particularly preferred.

In addition, 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 material (transparent resin film).

The thickness of the second protective layer 23 in this embodiment is 5-30 μm. If the thickness of the second protective layer 23 is less than 5μm, it will be used in the manufacturing process of the polarizing plate 2A However, the handling of the second protective layer 23 will cause difficulties, and the ability to protect the polarizer 21 will also be reduced. If the thickness of the second protective layer 23 exceeds 30 μm, it will not be able to meet the requirements for thinning the polarizing plate 2A obtained. From this viewpoint, the thickness of the second protective layer 23 is preferably 10 to 25 μm, and particularly preferably 12 to 24 μm.

Furthermore, the ratio of the thickness of the second protective layer 23 to the thickness of the polarizer 21 is 1.0 to 5.0. If the ratio is less than 1.0, the retention function for the thermal shrinkage of the polarizer 21 will become insufficient, and if the ratio exceeds 5.0, it will not be possible to cope with the thinning of the polarizing plate 2A. From this viewpoint, the ratio of the thickness of the second protective layer 23 to the thickness of the polarizer 21 is preferably 1.3 to 4.0, and 1.5 to 3.6 is particularly preferable.

Furthermore, from the viewpoint of preventing thermal shrinkage 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, considering the requirement for thinning of the polarizing plate 2A, about 8.0 or less is preferable.

In addition, the first protective layer 22 and the second protective layer 23 (hereinafter may be collectively referred to as "protective layers 22, 23") may also contain an ultraviolet absorber. This is because by disposing the protective layer containing the ultraviolet absorber on the visible side of the liquid crystal cell, it is possible to protect the liquid crystal cell from deterioration due to ultraviolet rays.

In addition, before the protective layers 22 and 23 are bonded to the polarizer 21, easy bonding treatments such as saponification treatment, corona treatment, primer treatment, and anchor coating treatment may be performed on the bonding surface. In addition, the surface of the protective layers 22 and 23 on the opposite side to the bonding surface of the polarizer 21 may have various places such as a hard coat layer, an anti-reflection layer, and an anti-glare layer Management layer.

(4) Adhesive layer

As an adhesive that constitutes an adhesive layer that can also be sandwiched between the polarizer 21 and the first protective layer 22 and/or between the polarizer 21 and the second protective layer 23, it can be selected according to the type and purpose of the object to be adhered. Use the appropriate one appropriately. For example, solvent-based adhesives, emulsion-type adhesives, water-based adhesives, pressure-sensitive adhesives, remoisturizing adhesives, polycondensation-type adhesives, solvent-free adhesives, film-like adhesives, and hot-melt adhesives剂 etc.

A preferable adhesive that constitutes the above-mentioned adhesive is a water-based adhesive. A representative example thereof is a polyvinyl alcohol-based resin as the main component. As a water-based adhesive, that is, commercially available polyvinyl alcohol-based resins, for example, KURARAY "KL-318" manufactured by CO., LTD, etc.

The water-based adhesive may contain a crosslinking agent. As the crosslinking agent, amine compounds, aldehyde compounds, methylol compounds, epoxy compounds, isocyanate compounds, polyvalent metal salts, etc. are preferred, and epoxy compounds are particularly preferred. As a commercially available product of the crosslinking agent, there are, for example, glyoxal or "Sumirez Resin 650 (30)" which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Company, Limited.

As another preferable adhesive agent, the adhesive agent comprised from the epoxy resin composition containing the epoxy resin hardened by irradiation or heating of an active energy ray is mentioned. When this adhesive is used, bonding between films can be performed by irradiating active energy rays or heating to the adhesive layer sandwiched between the films to harden the curable epoxy resin contained in the adhesive. The curing of epoxy resin based on active energy ray irradiation or heating is carried out by cationic polymerization of epoxy resin Preferably, the epoxy resin in this specification refers to a compound having two or more epoxy groups in the molecule.

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

(5) Manufacturing method of polarizing plate

The production of the polarizing plate 2A can be performed by a normal method. Hereinafter, as an example, a manufacturing method when an aqueous adhesive is used as the above-mentioned adhesive will be described.

First, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surfaces of the protective layers 22 and 23. The adhesive layer can be formed by, 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, and the like. In addition, it is also possible to adopt a method in which the polarizer 21 and the protective layers 22 and 23 are continuously supplied so that the bonding surfaces of the two are inside, while the adhesive is cast between them. After the adhesive is applied, heat treatment is performed as necessary to evaporate water, thereby drying the adhesive layer.

The film thickness of the adhesive layer can be arbitrarily set according to the characteristic design of the polarizing plate 2A, but from the viewpoint of reducing the cost of the adhesive material, the smaller one is better, and from the viewpoint of suppressing defects such as bubbles or foreign matter during bonding From the standpoint of view, the larger one is better, and from the standpoint of adhesion and durability, it is better to implement within the optimum range determined for each combination of the adherend and the adhesive. It is generally 0.005 to 10 μm, preferably 0.01 to 5 μm, and more preferably 0.03 to 1 μm.

When the polarizer 21 is attached to the protective layer 22, 23, it can also be Before forming the coating layer of the adhesive, one or both of the bonding surfaces are subjected to easy bonding treatments such as corona discharge treatment, plasma treatment, flame treatment, primer treatment, and anchor coating treatment.

After the adhesive layer is formed as described above, the first protective layer 22 is bonded to one surface of the polarizer 21 through the adhesive layer, and the second protective layer 23 is bonded to the other surface of the polarizer 21. Thereby, a polarizing plate 2A formed by stacking the first protective layer 22, the polarizer 21, and the second protective layer 23 can be obtained.

The total thickness of the polarizing plate 2A is preferably 15 to 170 μm. From the viewpoint of meeting the requirements for thinning in mobile communication applications and maintaining polarization performance, 20 to 100 μm is more preferable, and 30 to 80 μm is particularly preferable.

3. Peel off

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

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

It is preferable to perform a peeling process on at least one surface (especially the peeling surface in contact with the adhesive layer) of the said peeling sheet. Examples of release agents used in the release treatment include alkyd, silicone, fluorine, unsaturated polyester, Polyolefin-based and wax-based release agents. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability on a peeling sheet, and also includes any of the surface after a peeling process and the surface which showed peelability without a peeling process.

When laminating release sheets on both sides of the adhesive layer, use the release sheet on one side as a heavy-release release sheet with a large release force, and use the release sheet on the other side as a light release release sheet with a small release force. good.

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

4. Method for manufacturing polarizing plate with adhesive layer

As an example of the method of manufacturing the adhesive layer-attached polarizing plate 10A, first, a coating solution of the adhesive composition P is applied to the release surface of the release sheet, and after heat treatment is performed to form a coating film, the Another release sheet is laminated on the coating film (so that the release surface is in contact with the coating film) to obtain an adhesive sheet. When the above-mentioned coating film does not require a curing period, the adhesive layer is directly formed, and when the curing period is required, the adhesive layer is formed after the curing period. The conditions for heat treatment and curing are as described above.

As a method of applying the above-mentioned 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, etc. can be used.

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

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

[Second Embodiment]

Next, the polarizing plate with the adhesive layer of the second embodiment of the present invention will be described. The polarizing plate in this embodiment, as shown in FIG. 2, the polarizing plate 10B with the adhesive layer of this embodiment is configured to include: a composite polarizing plate 2B, and one side of the composite polarizing plate 2B laminated (in FIG. 2 The lower surface) of the adhesive layer 1. In addition, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 on the side opposite to the composite polarizing plate 2B side until the polarizing plate 10B with the adhesive layer is used.

The adhesive layer 1 is composed of the aforementioned adhesive in this embodiment.

The composite polarizing plate 2B in this embodiment is configured to include: a first retardation plate 24 in contact with the adhesive layer 1; and a second retardation located on the side opposite to the adhesive layer 1 of the first retardation plate 24 Plate 25 (corresponding to the second protective layer of the present invention); the second adhesive layer 26 sandwiched between the first retardation plate 24 and the second retardation plate 25; laminated on the sum of the second retardation plate 25 The polarizer 21 on the side opposite to the second adhesive layer 26 side; and the protective layer 27 laminated on the side opposite to the second retardation plate 25 of the polarizer 21 (corresponding to the first protective layer of the present invention) . In addition, 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 plate 25. Agent layer. The composite polarizing plate 2B can well exhibit the viewing angle compensation performance.

(1) The first phase difference plate

The first retardation plate 24 may be composed of a single layer expressing retardation, or may be composed of a plurality of layers including retardation expressing layers. The first retardation plate 24 is preferably configured to include a retardation expression layer 242 as shown in FIG. 3; a first acrylic resin laminated on one surface of the retardation display layer 242 (the lower surface in FIG. 3) Layer 241; and the second acrylic resin layer 243 laminated on the other surface of the retardation expression layer 242 (the upper surface in FIG. 3). The retardation expression layer 242 is preferably made of styrene resin. In this way, the composite polarizing plate 2B having the first retardation plate 24 has excellent viewing angle compensation performance in a liquid crystal display device, especially an IPS (In-Place-Switching) mode liquid crystal display device. The first retardation plate 24 is configured to include : The first acrylic resin layer 241, the retardation expression layer 242 formed of styrene resin, and the second acrylic resin layer 243. In addition, since the retardation expression layer 242 is protected by the first acrylic resin layer 241 and the second acrylic resin layer 243 existing on both surfaces, the first retardation plate 24 has excellent mechanical strength and chemical resistance.

In addition, it is preferable that the first retardation plate 24 is provided with in-plane retardation by extension. As a result, it becomes a better viewing angle compensation performance.

The styrene resin constituting the phase difference expression layer 242 may be a homopolymer of styrene or its derivatives, or a binary or more copolymer of styrene or its derivatives and other copolymerizable monomers. . Styrene derivatives refer to compounds with other groups bonded to styrene, for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4- Alkyl styrene such as dimethyl styrene, o-ethyl styrene, p-ethyl styrene, or hydroxy styrene Substituted benzene with hydroxyl, alkoxy, carboxyl, halogen, etc. introduced into the benzene nucleus of styrene, such as ene, tertiary butoxystyrene, vinyl benzoic acid, o-chlorostyrene, p-chlorostyrene, etc. Ethylene etc.

As the styrene resin, it is also possible to use the terpolymer disclosed in Japanese Patent Application Publication No. 2003-50316 or Japanese Patent Application Publication No. 2003-207640.

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 acrylonitrile, maleic anhydride, methyl methacrylate and butadiene. .

In addition, as the styrene resin constituting the retardation 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 retardation expression layer 242 is preferably 10-100 μm. By setting the thickness of the retardation expression layer 242 to 10 μm or more, a sufficient retardation value can be expressed by stretching. On the other hand, when the thickness of the retardation expression layer 242 is 100 μm or less, the impact strength is high, and the retardation change due to external stress is small, and when applied to a liquid crystal display device, thermal unevenness is unlikely to occur.

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 with a (meth)acrylic resin. By mixing rubber particles, the impact resistance of the acrylic resin layer can be improved.

Examples of (meth)acrylic resins include homopolymers of alkyl methacrylate or alkyl acrylate, or alkyl methacrylate and Copolymer of alkyl acrylate, etc. As alkyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc. are mentioned. Moreover, as alkyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, etc. are mentioned. Such (meth)acrylic resins can be those commercially available as general-purpose (meth)acrylic resins. Moreover, (meth)acrylic resins also include those called impact-resistant (meth)acrylic resins, or those that have a glutaric anhydride structure or a lactone ring structure in the main chain are called high heat resistance (methyl) ) Acrylic resin.

The rubber particles blended in the (meth)acrylic resin are preferably acrylic. The acrylic rubber particles refer to particles having rubber elasticity 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 by making a material with rubber elasticity into homogeneous particles, or may be a multilayer structure having at least one rubber elastic layer. Examples of acrylic rubber particles with a multilayer structure include: those having rubber elasticity as described above as the core and covering the surrounding with a hard alkyl methacrylate polymer; The base ester polymer is used as the core, and the surrounding is covered with an acrylic polymer having rubber elasticity as described above; and the surrounding of the hard core is covered with an acrylic polymer having rubber elasticity, and the surrounding is further covered Those covered with hard alkyl methacrylate polymers, etc.

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

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

As the (meth)acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243, those commercially available in a state where (meth)acrylic resin and acrylic rubber particles are mixed can be used. As an example of a commercially available product of (meth)acrylic resin ((meth)acrylic resin composition) compounded with acrylic rubber particles, each product name includes: sold by Sumitomo Chemical Co., Ltd. "HT55X" or "TechnolloyS001" are sold.

The glass transition temperature (Tg) of the (meth)acrylic resin composition is generally 160°C or less, but a (meth)acrylic resin composition having a glass transition temperature (Tg) of 120°C or less is preferred, and particularly preferred is (Meth)acrylic resin composition of 110°C or lower. That is, it is preferable that the glass transition temperature (Tg) of the phase difference expression layer 242 and the glass transition temperature (Tg) of the first acrylic resin 241 and the second acrylic resin layer 243 do not overlap, and the phase difference expression layer 242 has a ratio The first acrylic resin layer 241 and the second acrylic resin layer 243 preferably have a higher glass transition temperature (Tg).

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

The thicknesses of the first acrylic resin layer 241 and the second acrylic resin layer 243 are preferably 10-100 μm, respectively. If the thickness is 10 μm or more, film formation can be easily performed, and if 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. In addition, the thickness of the first acrylic resin layer 241 and the thickness of the second acrylic resin layer 243 are preferably substantially the same.

The surface on the side of the second adhesive layer 26 of the first phase difference plate 24 may be subjected to surface treatment such as corona treatment.

When manufacturing the first phase difference plate 24, for example, a styrene resin and a (meth)acrylic resin composition containing rubber particles may be co-extruded and then stretched. It can be extended by longitudinal uniaxial extension, tenter transverse uniaxial extension, simultaneous biaxial extension, or successive biaxial extension, as long as the extension can achieve the desired retardation value. In addition to the above methods, it is also possible to separately fabricate single-layer films (the phase difference expression layer 242, the first acrylic resin layer 241, and the second acrylic resin layer 243), and then heat-bond these films by thermal lamination. , Extend its laminate.

In addition, the total thickness of the stretched first phase difference plate 24 is preferably 5 to 100 μm, more preferably 10 to 50 μm, from the viewpoint of maintaining sufficient performance and meeting the requirements for thinning in mobile communication applications. 15~30μm is particularly good.

The surface of the first retardation plate 24 that is in contact with the adhesive layer 1 is composed of the first acrylic resin layer 241. In this case, the adhesive layer 1 has a higher adhesive force to the first acrylic resin layer 241 Therefore, the polarizing plate 10B with the adhesive layer has excellent durability under high temperature conditions, humid heat conditions, thermal shock, etc.

(2) Second phase difference plate

The second phase difference plate 25 of this embodiment corresponds to the second protective layer of the present invention. As the second phase difference plate 25, the second phase difference plate 25 of the first embodiment can be used The protective layer 23 is the same.

(3) The second adhesive layer

As the adhesive that constitutes the second adhesive layer 26, a well-known adhesive can be used. "It can be a curable adhesive or a non-curable adhesive, but from the viewpoint of suppressing dimensional changes due to thermal shrinkage of the polarizing plate In view of this, it is better to use an active energy ray-curable adhesive.

The active energy ray curable adhesive can be a polymer with active energy ray curability as the main component, or a polymer without active energy ray curability and a multifunctional monomer with active energy ray curability. / Or a mixture of oligomers as the main component. In addition, it can be a mixture of a polymer with active energy ray curability and a polymer without active energy ray curability, or a polymer with active energy ray curability and a multifunctional monomer with active energy ray curability. And/or a mixture of oligomers may also be a mixture of these three types.

Among the above, from the viewpoint of easily obtaining an adhesive that maintains adhesiveness and exerts cohesive force, a combination of a polymer that does not have active energy ray curability and a multifunctional monomer and/or oligomer that has active energy ray curability It is preferable to use a mixture as the main component, and it is particularly preferable to use a mixture of a polymer having no active energy ray curability and a polyfunctional monomer having active energy ray curability as the main component.

As a polymer that does not have active energy ray curable properties, (meth)acrylate polymers that do not have active energy ray curable groups (hereinafter referred to as "(meth)acrylate polymer (X)") are more good. The (meth)acrylate polymer (X) is a (methyl) containing alkyl group with 1 to 20 carbon atoms Alkyl acrylate is preferred as the monomer constituting the polymer. Thereby, the obtained adhesive can exhibit better adhesion. In addition, (meth)acrylate polymer (X) series, alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group, monomers having reactive functional groups (reactive functional group-containing monomers Copolymers of monomers) and other monomers used as needed are particularly preferred. By making the (meth)acrylate polymer (X) contain a reactive functional group-containing monomer as a monomer constituting the polymer, it is possible to improve the adhesion to the glass surface of the liquid crystal cell, etc., and also by It reacts with the crosslinking agent (Z) mentioned later to form a crosslinked structure.

Examples of alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, N-Butyl (meth)acrylate, n-pentyl (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, stearyl (meth)acrylate Wait. Among them, from the viewpoint of further improving adhesiveness, (meth)acrylate having an alkyl group with 1 to 8 carbon atoms is preferred, and n-butyl (meth)acrylate is particularly preferred. In addition, these can be used alone or in combination of two or more kinds.

The (meth)acrylate polymer (X) preferably contains an alkyl (meth)acrylate having 1 to 20 carbon atoms containing 50 to 99% by mass of alkyl groups as the monomer unit constituting the polymer It is particularly preferable to contain 60 to 99% by mass, and more preferably 70 to 98% by mass.

As the above-mentioned reactive functional group-containing monomer, a monomer having a hydroxyl group in the molecule (a hydroxyl group-containing monomer) and a monomer having a carboxyl group in the molecule are preferably mentioned. (Carboxyl group-containing monomer), monomers having an amine group in the molecule (amine group-containing monomer), etc. These reactive functional group-containing monomers can be used alone or in combination of two or more.

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

Examples of carboxyl group-containing monomers 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 the reactivity of the carboxyl group of the obtained (meth)acrylate polymer (X) with the crosslinking agent (Z) and the copolymerizability with other monomers. These can be used alone or in combination of two or more.

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

The (meth)acrylate polymer (X) preferably contains 1 to 25% by mass of a reactive functional group-containing monomer as the monomer unit constituting the polymer, and particularly preferably contains 1 to 20% by mass, and further Preferably it contains 2-5 mass %.

The polymerization aspect 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 300,000 to 3 million, particularly preferably 1 million to 2.5 million, and further preferably 1.6 million to 2.2 million.

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

As an active energy ray-curable polyfunctional monomer (hereinafter, sometimes referred to as "active energy ray-curable compound (Y)"), molecular weight excellent in compatibility with (meth)acrylate polymer (X), etc. A polyfunctional acrylate monomer of 1000 or less is preferable.

Examples of polyfunctional acrylate monomers having a molecular weight of 1,000 or less include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl Glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxytrimethyl acetate neopentyl glycol bis(meth) Base) acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified phosphoric acid di(meth)acrylate, Bifunctional type such as bis(acryloxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri( Meth) acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri-(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tri(meth)acrylate Acrylic oxyethyl) isocyanurate, ε-caprolactone modified tris (2-(meth) acryloxy ethyl) isocyanurate and other trifunctional types; diglycerol tetra(methyl) 4-functional type such as acrylate, pentaerythritol tetra(meth)acrylate; propionic acid modified dipentaerythritol penta(meth)acrylate and other 5-functional type; dipentaerythritol hexa(meth)acrylate, caprolactone modified 6-functional type such as dipentaerythritol hexa(meth)acrylate. These can be used alone or in combination of two or more.

The content of active energy ray hardening compound (Y) is relative to (former 100 parts by mass of the acrylate polymer (X) are preferably 1-50 parts by mass, particularly preferably 5-30 parts by mass, and more preferably 10-20 parts by mass.

It is also preferable 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 monomer and a crosslinking agent (Z) as the monomer units constituting the polymer, if the adhesive is When the agent is heated or the like, the crosslinking agent (Z) reacts with the reactive functional group of the reactive functional group-containing monomer constituting the (meth)acrylate polymer (X). Thereby, a structure in which the (meth)acrylate polymer (X) is crosslinked by the crosslinking agent (Z) is formed, and the cohesive force of the obtained adhesive is improved.

As the crosslinking agent (Z), what is necessary is to react with the reactive functional group possessed by the (meth)acrylate polymer (X). For example, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, Amine crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxide crosslinking agent, metal chelate Compound-based cross-linking agents, metal salt-based cross-linking agents, ammonium salt-based cross-linking agents, etc. As the isocyanate-based crosslinking agent, the same as the aforementioned isocyanate-based crosslinking agent (B) can be used. In addition, the crosslinking agent (Z) may be used alone or in combination of two or more.

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

The above-mentioned active energy ray-curable adhesives can also contain various additives as required, such as: photopolymerization initiator, silane coupling agent, refractive index adjuster, antistatic agent, thickener, antioxidant, ultraviolet absorber, 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 preferable that the active energy ray-curable adhesive contains a photopolymerization initiator.

As the photopolymerization initiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1 -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) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobis Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-Chlorothioxanthone, 2,4-Dimethylthioxanthone, 2,4-Diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethyl ketal Aminobenzoic acid ester, oligomer [2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl] acetone], 2,4,6-trimethylbenzyl Group-diphenyl-phosphine oxide and the like. These can be used alone or in combination of two or more.

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

In addition, from the viewpoint of improving the adhesion of the resulting adhesive to the film, the active energy ray-curable adhesive preferably contains a silane coupling agent. As a silane coupling agent, it has at least one alkoxysilane in the molecule -Based organosilicon compound, which has good compatibility with the adhesive component and has light transmittance.

As the silane coupling agent, for example, in addition to the epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), a polymerizable unsaturated group-containing silicon compound (for example, vinyl trimethoxy Silane, vinyl triethoxy silane, methacryloxy propyl trimethoxy silane, etc.), amino-containing silicon compounds (such as 3-amino propyl trimethoxy silane, N-(2-amine Ethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc.), 3-chloropropyltrimethoxysilane Triethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, and an alkyl-containing silicon compound (such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethyl Condensates of oxysilane, ethyl trimethoxysilane, etc.). These can be used alone or in combination of two or more.

The content of the silane coupling agent relative to 100 parts by mass of the (meth)acrylate polymer (X) is preferably 0.01-10 parts by mass, particularly preferably 0.05-5 parts by mass, further preferably 0.1-1 parts by mass .

In addition, the above-mentioned active energy ray-curable polymer system has an active energy ray-curable functional group (active energy ray-curable group) introduced into the side chain (meth)acrylate (co)polymer. 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 will decrease, and if it is too thick, it is easy to cause problems such as the adhesive being squeezed out.

(4) Polarized photons

As the polarizer 21, the polarizer 21 of the polarizer 2A can be used. The same.

(5) Protective layer

The protective layer 27 of this 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 sandwiched between the polarizer 21 and the protective layer 27 and/or between the polarizer 21 and the second retardation plate 25 may be the same as the adhesive layer of the polarizer 2A described above.

(7) Manufacturing method of composite polarizing plate

The manufacture of the composite polarizing plate 2B can be performed by a normal method. Hereinafter, as an example, a manufacturing method when an aqueous adhesive is used as the above-mentioned adhesive will be described.

First, a coating film of the adhesive constituting the second adhesive layer 26 is formed on the release surface of the release sheet. Specifically, the coating liquid of the adhesive which comprises the 2nd adhesive layer 26 is apply|coated to the peeling surface of a peeling sheet, and it is 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 retardation plate 25 and the protective layer 27. The formation of this adhesive layer can be performed by the same method as the manufacturing method of the aforementioned polarizing plate 2A. In addition, the thickness of the adhesive layer and easy bonding treatment are also the same.

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

Next, the coating film of the adhesive which constitutes the 2nd adhesive layer 26 on the said peeling sheet was stuck on the surface of the 2nd phase difference plate 25 side of the obtained laminated body. Then, active energy rays are irradiated through the release sheet to harden the coating film of the adhesive, and the coating film is used as the second adhesive layer 26.

Here, the active energy rays refer to those having energy quantum in electromagnetic waves or charged particle beams, and specifically, ultraviolet rays, electron beams, etc. are mentioned. Among active energy rays, ultraviolet rays, which are easy to handle, are particularly preferred.

The irradiation of ultraviolet rays can be carried out by high-pressure mercury lamps, metal halide lamps, molten H lamps, xenon lamps, etc. The irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW/cm ² . In addition, the amount of light is preferably 50 to 10000 mJ/cm ² , more preferably 80 to 5000 mJ/cm ² , particularly preferably 100 to 1000 mJ/cm ² . On the other hand, the electron beam irradiation 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 phase difference plate 24 is bonded to the exposed second adhesive layer 26 . Thereby, a composite polarizing plate 2B in which the protective layer 27, the polarizer 21, the second phase difference plate 25, the second adhesive layer 26, and the first phase difference plate 24 are laminated is obtained.

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

(8) Manufacturing method of polarizing plate with adhesive layer

As an example of the manufacturing method of the polarizing plate 10B with the adhesive layer, the adhesive sheet formed by the two-area peeling sheet of the adhesive layer is prepared as the adhesive sheet of this embodiment, and the peeling sheet on one side (light peeling type) Peel off sheet). Ran After that, the first retardation plate 24 of the composite polarizing plate 2B is superimposed on the exposed adhesive layer, and the adhesive sheet and the composite polarizing plate 2B are press-bonded. Thereby, the above-mentioned polarizing plate 10B with an adhesive layer (with a release sheet) can be obtained.

As another example of the method of manufacturing the adhesive layer-attached polarizing plate 10B, the coating solution of the adhesive composition P is applied to the peeling surface of the release sheet, and after heat treatment is performed to form a coating film, the composite polarizing plate 2B The first retardation plate 24 is superimposed on the coating film. When the above-mentioned coating film needs a curing period, the curing period is separated to form the adhesive layer 1, and when the curing period is not required, the adhesive layer 1 is directly formed. Thereby, the above-mentioned polarizing plate 10B with an adhesive layer (with a release sheet) 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 this embodiment relative to the adhesive force of the alkali-free glass is preferably 0.5-20N/25mm, particularly preferably 1-10N/25mm. Thereby, the polarizing plate with the adhesive layer becomes one with excellent durability. Furthermore, from the viewpoint of having excellent reprocessing properties, the above-mentioned adhesive force is preferably 1.5-7N/25mm. In addition, the adhesive force mentioned here refers to the adhesive force measured by the 180° peel method basically in accordance with JIS Z0237:2009, and is set as follows: Set the measurement sample to be 25 mm wide and 100 mm long, and place the measurement sample on After applying pressure at 0.5 MPa and 50°C for 20 minutes and sticking to the body, leaving it for 24 hours under normal pressure, 23°C, and 50% RH, and then measuring at a peeling speed of 300 mm/min. By keeping the adhesive force within the above range, it is possible to prevent warpage or surface peeling when attaching to the liquid crystal cell.

In addition, the polarizing plates 10A and 10B with the adhesive layer of this embodiment are further heated at 23°C and 50%RH after being attached to the above-mentioned body. Adhesion (adhesive force after 14 days of attachment) is 1~20N/25mm, particularly preferably 3~9N/25mm after being placed for 14 days. By suppressing the increase in the adhesive force with the passage of time in this way, the polarizing plates 10A and 10B with the adhesive layer of the present embodiment are also excellent in reprocessing properties, and can be easily reattached after being attached to the liquid crystal cell.

In addition, the adhesive layer-attached polarizing plates 10A and 10B of this embodiment have been attached to the above-mentioned substrate and left for 2 days under the conditions of 50°C and 50%RH. Adhesive strength after 2 days) From the standpoint of durability, 1-20N/25mm is preferable, and from the standpoint of reprocessing properties, 6-12N/25mm is particularly preferable.

The surface resistivity of the adhesive layer of the polarizing plates 10A and 10B with the adhesive layer of this embodiment is preferably 1.0×10 ¹² Ω/sq or less, particularly preferably 5.0×10 ¹¹ Ω/sq or less, and furthermore Preferably, it is 7.0×10 ¹⁰ Ω/sq or less. By making the surface resistivity below the above-mentioned value, sufficient antistatic properties can be exhibited in the display panel. This surface resistivity can be achieved by making the adhesive composition P contain the aforementioned antistatic agent (D). In addition, the measurement of the surface resistivity of the adhesive layer was performed in accordance with JIS K6911, and the details are as shown in the test example described later. In addition, the lower limit of the above-mentioned surface resistivity is not particularly limited, but it is about 5.0×10 ⁸ Ω/sq from the viewpoint of not adversely affecting durability and heat-resistant unevenness.

6. Use of polarizing plate with adhesive layer

It can be manufactured by using polarizing plates 10A and 10B with adhesive layers, for example, a liquid crystal display device equipped with a liquid crystal cell and a polarizing plate.

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

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

In addition, the adhesive layer-attached polarizing plates 10A and 10B of the present embodiment are also excellent in stress relaxation properties, and the resulting liquid crystal display device is also less likely to warp under high temperature conditions, and heat unevenness is less likely to occur. For example, if the glass plates with the polarizing plates 10A and 10B attached with the adhesive layer are placed under high temperature conditions (for example, at 80~85℃) for 250 hours, they will not easily warp, which makes it difficult to produce Uneven heat. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a thin film, the liquid crystal display device is not easily warped, and even if the liquid crystal cell is a high-definition liquid crystal cell, heat unevenness is not easily generated.

Here, there may be a transparent conductive film 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 above-mentioned transparent conductive film include metals such as platinum, gold, silver, and copper, tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc dioxide. Other oxides, 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 and other composite oxides, chalcogenide Non-oxidizing compounds such as lanthanum hexaboride, titanium nitride, and titanium carbide.

The above-described embodiments are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, it is intended that the various elements disclosed in the above-mentioned embodiments also include all design changes and equivalents belonging to the technical scope of the present invention.

[Example]

Hereinafter, the present invention will be further described in detail through examples, but the scope of the present invention is not limited to these examples.

[Example 1]

1. Manufacture of polarizing plate

(1) Production of polarized photons

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

(2) Production of polarizing plate

Prepare 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 water-soluble epoxy resin, namely polyamide epoxy additive (Taoka Chemical Co., Ltd.) was added to the aqueous solution. Produced, the epoxy adhesive obtained by the trade name "Sumirez Resin 650 (30)", an aqueous solution with a solid content of 30% by mass). This epoxy-based adhesive is applied to one side of the polarizer obtained as described above.

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

Next, on the other side of the polarizer, an epoxy-based adhesive was applied in the same manner as above, and on the coating layer, a 23μm thick zero retardation film (Zeon Corporation, trade name "ZEONOR") as the second protective layer. Then, it was dried at 80° C. for 5 minutes, thereby adhering the first protective layer and the second protective layer to the polarizer. After that, curing at 40°C for 168 hours, the total thickness of the first protective layer (layer thickness 25μm), polarizer (elongation ratio 5 times, layer thickness 15μm) and the second protective layer (layer thickness 23μm) is obtained. Polarizing plate. In addition, 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. In addition, 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. Manufacturing of composite polarizing plate

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

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

By using 100 parts by mass of the (meth)acrylate polymer (X) as the active energy ray-curable compound (Y) (polyfunctional monomer), tris(acryloxyethyl) isocyanurate (Manufactured by TOAGOSEI CO., LTD., trade name "ARONIXM-315") 15 parts by mass, as a crosslinking agent (Z) trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Trade name "CORONATEL") 0.3 parts by mass, a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1:1 as a polymerization initiator (manufactured by Chiba Specialty Chemicals, product (Name "IRGACURE500") 1.5 parts by mass, and 0.2 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403") as a silane coupling agent. , Fully stirred and diluted with ethyl acetate to obtain an active energy ray-curable adhesive coating solution.

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

(2) Fabrication of the first phase difference plate

The acrylic resin layer with an average particle diameter of 200 nm that constitutes the first acrylic resin layer The methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "Technolloy S001") containing about 20% by mass of olefinic rubber particles, and the styrene-maleic anhydride copolymer resin (NOVA Chemicals Corporation., trade name "DYLARK D332"), and methacrylic resin (Sumitomo Chemical Co., Ltd.) blended with about 20% by mass of acrylic rubber particles with an average particle diameter of 200 nm constituting the second acrylic resin layer Manufacture, trade name "Technolloy S001"), and 3-layer co-extrusion was performed in this order to obtain a 3-layer laminated film. The obtained laminated film was stretched to obtain a first phase difference plate (first acrylic resin layer/phase difference expression layer/second acrylic resin layer) having an in-plane retardation value of 60 nm and a thickness of 25 μm.

(3) Production of composite polarizing plate

First, prepare the aforementioned polarizing plate. The first protective layer and the second protective layer of the polarizing plate are respectively equivalent to the protective layer and the second phase difference plate of the composite polarizing plate produced here. That is, a polarizing plate in which a protective layer, a polarizer, and a second retardation plate are laminated is prepared.

The surface of the polarizing plate on the second phase difference plate side is laminated with the active energy ray curable adhesive film obtained by the above process (1), and the release sheet is irradiated with ultraviolet rays under the following conditions to make the adhesive The coating film is cured to become the second adhesive layer. Then, after peeling off the release sheet from the obtained second adhesive layer, the second acrylic phase difference plate of the first phase difference plate obtained by the above process (2) is bonded to the exposed surface of the second adhesive layer The surface on the resin layer side. In this way, a composite polarized light with a total thickness of 93μm is obtained by laminating a protective layer (first protective layer), polarizers, a second retarder (second protective layer), a second adhesive layer, and a first retarder. board. In addition, the formed second adhesive layer The thickness is 5μm.

<Ultraviolet radiation conditions>

‧Use high pressure mercury lamp

‧Illumination 300mW/cm ² , light intensity 300mJ/cm ²

‧Using the UV illuminance/light meter made by EYE GRAPHICS CO.,LTD. "UVPF-A1"

3. Manufacturing of polarizing plate with adhesive layer

(1) Preparation of (meth)acrylate copolymer

87 parts by mass of n-butyl acrylate, 5 parts by mass of isobornyl acrylate, 5 parts by mass of 2-phenylethyl acrylate, and 3 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare a (meth)acrylate copolymer (A). The molecular weight of the (meth)acrylate copolymer (A) was measured by the method described below, and as a result, the weight average molecular weight (Mw) was 1.6 million. In addition, the hydroxyl value of the (meth)acrylate copolymer (A) can be calculated based on the above-mentioned compounding as 14.49 mgKOH/g and the acid value is 0 mgKOH/g.

(2) Preparation of adhesive composition

100 parts by mass of the (meth)acrylate copolymer (A) obtained by the above process (1) and trimethylolpropane as the isocyanate-based crosslinking agent (B) were modified to xylylene diisocyanate (Mitsui Chemicals, Inc., trade name "TAKENATE D110N") 0.2 parts by mass, 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd) as an epoxy-containing silane coupling agent (C1) . Manufacturing, trade name "KBM403") 0.2 parts by mass, as a mercapto-containing silane coupling agent (C2), 3-mercaptopropyl trimethoxysilane and methyl triethoxysilane co-condensate (Shin-Etsu Chemical Manufactured by Co.,Ltd., Trade name ""X-411-1810", mercapto equivalent: 450g/mol) 0.2 parts by mass, and N-octyl-4-methylpyridinium hexafluorophosphate (room temperature) as an antistatic agent (D) The following is a solid ionic compound) 2.0 parts by mass, mixed, fully 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-based 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 (a solid ionic compound at room temperature)

(3) Production of polarizing plate with adhesive layer

A release sheet (SP-PET3811, manufactured by LINTEC Corporation, produced by LINTEC Corporation, with a silicone release agent on one side of the polyethylene terephthalate film Thickness: 38 μm), after coating the obtained coating solution of the adhesive composition with a knife coater, heat treatment at 90°C for 1 minute to form a coating film of the adhesive composition.

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

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

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

In addition to mixing the types and ratios of the monomers constituting the (meth)acrylate copolymer (A), the weight average molecular weight of the (meth)acrylate copolymer (A), and the isocyanate-based crosslinking agent (B) Except that the amount was changed as shown in Table 1, the polarizing plate with the first and second adhesive layers was produced in the same manner as in Example 1.

Here, the aforementioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.

<Measurement conditions>

. GPC measuring device: 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 solvent: tetrahydrofuran

. Measuring temperature: 40℃

[Test Example 1] (Measurement of Gel Fraction)

A peeling sheet (manufactured by LINTEC Corporation, SP-PET3801, thickness: 38μm) in which one side of a polyethylene terephthalate film was peeled off with a silicone-based release agent was used to produce an adhesive sheet instead of the example or the comparative example Optical film used in the production of polarizing plates with adhesive layers. Specifically, on the exposed coating film of the structure composed of the release sheet obtained in the manufacturing process of the embodiment or the comparative example and the coating film of the adhesive composition, the above-mentioned release sheet is in contact with the release treatment surface side Laminate in the same way, curing for 7 days at 23°C and 50%RH. Thus, an adhesive sheet composed of a structure of release sheet (SP-PET3801)/adhesive layer (thickness: 20 μm)/release sheet (SP-PET3811) was produced.

The obtained adhesive sheet was cut into a size of 80mm×80mm, and the adhesive layer was covered with a polyester mesh (mesh size 200), and the mass was weighed with a precision balance and subtracted The mass of the above-mentioned net-like fabric alone is used to calculate the mass of only the adhesive. Let the mass at this time be M1.

Next, the adhesive coated on the polyester mesh fabric was immersed in ethyl acetate at room temperature (23°C) for 24 hours. Then take out the adhesive and dry it in the air for 24 hours at a temperature of 23°C and a relative humidity of 50%. Dry in an oven at 80°C for 12 hours in one step. After drying, weigh the mass with a precision balance, and subtract the mass of the mesh fabric alone to calculate the mass of only the adhesive. Let the mass at this time be M2. Gel fraction (%) is represented by (M2/M1)×100. The results are shown in Table 2 and Table 3.

[Test Example 2] (Evaluation of Durability)

The polarizing plate with the adhesive layer obtained in the example or the comparative example was cut out to prepare a sample with a size of 150 mm×200 mm. After peeling off the peeling sheet from the sample and affixed to alkali-free glass (Eagle XG manufactured by Corning Incorporated) through the exposed adhesive layer, it was pressurized in an autoclave manufactured by KURIHARA Manufacturing at 0.5 MPa and 50°C for 20 minutes .

After that, it was put into the environment under the following three endurance conditions, and after 250 hours, it was confirmed whether there was lifting or surface peeling with a 10x magnifying glass. The evaluation criteria are as follows. Table 2 shows the results of the polarizing plates with the first adhesive layer of Examples 1 to 12 and Comparative Examples 1 to 5, and Table 2 shows the results of Examples 1 to 13 and Comparative Examples 1 to 7 with the second adhesive The results of the polarizing plate of the agent layer are shown in Table 3.

⊚: Lifting or surface peeling is not confirmed.

○: Lifting or surface peeling of a size of 0.5 mm or less is confirmed.

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

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

<Endurance Conditions>

. Heat resistance: 85℃ dry

. Humidity and heat: 60℃, relative humidity 90%RH

70℃下各30分鐘的熱衝擊試驗，200循 環 . HS: -35°C

Thermal shock test at 70℃ for 30 minutes each, 200 cycles

[Test Example 3] (Evaluation of Warpage Resistance)

The polarizing plate with the adhesive layer obtained in the Examples or Comparative Examples was cut to a length of 200 mm and a width of 150 mm. The peeling 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") with a length of 250 mm, a width of 175 mm, and a thickness of 0.5 mm. ), use this as a sample. The sample was placed at 85°C in a dry atmosphere for 250 hours. After that, it was taken out under an environment of 25°C and 50% RH, and the polarizing plate was placed on a horizontal platform with the side of the polarizing plate facing up, and the amount of warpage (distance between the corner and the stage) of each corner (4 points) of the sample from the stage ) To add up the warpage of each corner. Based on the results, the warpage resistance was evaluated as follows. Table 2 shows the results of the polarizing plates with the first adhesive layer of Examples 1 to 12 and Comparative Examples 1 to 5, and Table 2 shows the results of Examples 1 to 13 and Comparative Examples 1 to 7 with the second adhesive The results of the polarizing plate of the agent layer are shown in Table 3.

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

○: The total amount of warpage exceeds 10mm but less than 15mm

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

×: The total amount of warpage exceeds 20 mm

[Test Example 4] (Evaluation of Heat Inhomogeneity)

The adhesive layer-attached polarizing plate obtained in the examples or comparative examples was adjusted to a size of 200 mm×150 mm with a cutting device (Super Cutter PN1-600 manufactured by Ogino Seisakusho Co., Ltd.). After peeling off the peeling sheet and pasting the exposed adhesive layer on non-alkali glass (made by Corning Incorporated, Eagle XG), use an autoclave manufactured by KURIHARA at 0.5MPa, Press at 50°C for 20 minutes. In addition, the above-mentioned bonding is performed on the surface and back of the alkali-free glass so that the polarization axis of the polarizing plate with the adhesive layer is in the orthogonal polarization state (polarization axis: ∠45°, ∠135°). In this state, put it in a dry environment at 80°C for 250 hours, then place it in an environment of 23°C and 50% RH for 2 hours. This was used as a sample, and the heat unevenness was evaluated by the method shown below . Table 2 shows the results of the polarizing plates with the first adhesive layer of Examples 1 to 12 and Comparative Examples 1 to 5, and Table 2 shows the results of Examples 1 to 13 and Comparative Examples 1 to 7 with the second adhesive The results of the polarizing plate of the agent layer are shown in Table 3.

<Evaluation method>

The above sample was set on a flat lighting device (FLAT ILLUMINATOR) (Raytronics Corp., manufactured, HF-SL-A312LC, illuminance: 26,000 Lux, brightness: 10,000 cd), and a two-dimensional color luminance meter (KONICA MINOLTA, INC. made, CA-2000) to shoot, and use analysis software (KONICA MINOLTA, INC. make, CA-S20w) to convert into a brightness distribution image. The brightness distribution image of the obtained sample was evaluated based on the evaluation criteria shown in FIG. 4 and the following.

◎: The brightness distribution is approximately uniform.

○: The brightness distribution on the four sides is slightly distorted.

△: The brightness distribution on the four sides is obviously distorted.

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

[Test Example 5] (Measurement of Adhesive Force-Evaluation of Reprocessability)

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

After leaving for 14 days under the conditions of 23° C. and 50% RH, the adhesion was further measured in the same manner as above (adhesive strength after 14 days of adhesion; N/25mm). The difference is that the polarizing plates with the second adhesive layer of Examples 1 to 13 and Comparative Examples 1 to 7 were left for 2 days under the conditions of 50°C and 50% RH, and then measured in the same manner as above. Adhesion (adhesion after 2 days at 50℃; N/25mm).

Based on the adhesive force 14 days after the application, the reprocessing properties were evaluated using the following criteria. The results are shown in Table 2.

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

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

△: Adhesive strength after 14 days of application is 10N/25mm or more but less than 20N/25mm

×: Adhesive force after 14 days of attachment is 20N/25mm or more

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

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

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

【Table 2】

It can be seen from Table 2 and Table 3 that the adhesive layer-attached polarizing plates obtained in the examples have excellent durability, and are not easy to warp and not easily under high temperature. Easy to produce uneven heat. In addition, the adhesive layer-attached polarizing plate obtained in the examples has a low surface resistivity of the adhesive layer and a small adverse effect on liquid crystal cells and the like. Furthermore, the reworkability of the polarizing plate with an adhesive layer obtained in Examples 1-12 is also excellent.

[Industrial availability]

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

10A‧‧‧Polarizing plate with adhesive layer

1‧‧‧Adhesive layer

2A‧‧‧Polarizer

21‧‧‧Polarized photons

22‧‧‧The first protective layer

23‧‧‧Second protection layer

Claims (14)

A polarizing plate with an adhesive layer, comprising: a polarizer; a first protective layer laminated on one side of the polarizer; a second protective layer laminated on the other side of the polarizer; and laminated on the first side 2 The adhesive layer of the protective layer on the side opposite to the surface on the polarizer side, 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 60~89% adhesive composition, the aforementioned adhesive composition contains: (meth)acrylate copolymer (A) contains alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2) and The hydroxyl monomer (a3) is the monomer unit constituting the polymer, with a hydroxyl value of 5-20 mgKOH/g, an acid value of 5 mgKOH/g or less, and a weight average molecular weight of 1.3 million to 3 million; and an isocyanate-based crosslinking agent ( B), the second protective layer is made of cycloolefin resin or triacetyl cellulose, the thickness of the polarizer is 1-20μm, the thickness of the second protective layer is 5-30μm, the thickness of the second protective layer The ratio to the thickness of the aforementioned polarizer is 1.0 to 5.0. The polarizing plate with adhesive layer as described in the first item of the patent application, wherein the thickness of the first protective layer is 5~120μm, 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 item 1 of the scope of the patent application, wherein the first protective layer is composed of triacetyl cellulose. The polarizing plate with adhesive layer as described in the first item of the patent application, wherein the alicyclic structure of the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure. The polarizing plate with adhesive layer as described in the first item of the patent application, wherein the adhesive composition further contains an epoxy-containing silane coupling agent (C1). The polarizing plate with adhesive layer as described in the first item of the patent application, wherein the adhesive composition further contains a mercapto-containing silane coupling agent (C2). The polarizing plate with an adhesive layer as described in item 1 of the scope of patent application, 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 that is solid at room temperature and is composed of nitrogen-containing heterocyclic cations and halogenated phosphoric acid anions . The polarizing plate with an adhesive layer as described in the first item of the scope of patent application, wherein the aforementioned isocyanate-based crosslinking agent (B) is a compound having an aromatic ring. The polarizing plate with an adhesive layer as described in the first item of the patent application, 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 item 1 of the scope of the patent application, wherein the (meth)acrylate copolymer (A) contains 1-40% by mass of the alicyclic structure-containing monomer (a1) As a monomer unit constituting the polymer. The polarizing plate with an adhesive layer as described in the first item of the patent application, wherein the (meth)acrylate copolymer (A) contains 1-40% by mass of the aromatic ring-containing monomer (a2) as a constituent The monomer unit of the polymer. The polarizing plate with an adhesive layer as described in item 1 of the scope of patent application, wherein the (meth)acrylate copolymer (A) contains 0.5-10% by mass of the hydroxyl-containing monomer (a3) as the constituent The monomer unit of the polymer. The polarizing plate with an adhesive layer as described in the first item of the patent application, wherein the surface resistivity of the adhesive layer is 1.0×10 ¹² Ω/sq or less.

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