TWI691577B - Optical film with adhesive layer - Google Patents

Abstract

The present invention provides an optical film with an adhesive layer, which is excellent in durability and hardly generates thermal unevenness even when a thinned optical film is used. An optical film (10A) with an adhesive layer, comprising an optical film, and an adhesive layer (1) laminated on at least one side of the optical film. In the optical film (10A) with an adhesive layer, the optical film The surface in contact with the adhesive layer (1) is composed of acrylic resin, and the adhesive layer (1) is composed of an adhesive obtained from an adhesive composition containing the (meth)acrylate The copolymer (A) contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer; and a crosslinking agent (B), and the content of the low molecular weight component is 5 Mass% or less.

Description

Optical film with adhesive layer

The present invention relates to an optical film with an adhesive layer, and particularly to an optical film with an adhesive layer used when an optical film such as a polarizing plate or a composite polarizing plate is bonded to a liquid crystal cell or the like.

In recent years, as display panels of various electronic devices, touch panels that double as display devices and input mechanisms are widely used. The types of touch panels are mainly resistive film type, capacitive type, optical type and ultrasonic type. Resistive film type has analog resistive film type and matrix resistive film type; capacitive type has surface type and projection type.

Recently, projection-type capacitors are widely used in touch panels of mobile electronic devices such as smart phones or tablet computers. As a projection type capacitive touch panel of a related mobile electronic device, for example, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, and a transparent layer are sequentially deposited from below Protective plates such as conductive film (ITO) and tempered glass.

As an optical component constituting the liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell is generally configured such that the alignment layers of the two transparent electrode substrates forming the alignment layer are inside and a predetermined interval is formed by a spacer, and the surroundings are sealed and the liquid crystal material is sandwiched between the two transparent electrode substrates. Usually, the two transparent electrode substrates in the liquid crystal cell are respectively adhered by an adhesive There are composite polarizing plates with polarizing plates or phase difference plates.

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

【Prior Technical Literature】

【Patent Literature】

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

Here, with the recent demand for thinner mobile electronic devices, thinner films such as polarizing plates are also required. However, the film polarizing plate has a high shrinkage rate due to heat and the like, and the conventional adhesives such as Patent Document 1 may warp or peel off the surface under high-temperature conditions or humid heat conditions. It is also pointed out that due to the stress during the thermal contraction of the optical film, the problem of light leakage (so-called thermal unevenness) caused by the deviation of the optical axis of the optical film occurs.

In addition, when the optical film is preferentially thinned, the adhesiveness with the adhesive deteriorates, and in conventional adhesives such as Patent Document 1, the adhesiveness at the interface between the optical film and the adhesive is insufficient, resulting in durability There is a tendency to deteriorate further.

The present invention was completed in view of this actual situation, and its purpose is Provided is an optical film with an adhesive layer, which is excellent in durability and hardly generates thermal unevenness even when a thinned optical film is used.

In order to achieve the above object, firstly, the present invention provides an optical film with an adhesive layer, comprising: an optical film; and an adhesive layer laminated on at least one side of the optical film; and the optical film with an adhesive layer, The surface of the optical film that is in contact with the adhesive layer is composed of an acrylic resin, the adhesive layer is composed of an adhesive obtained from an adhesive composition, and the adhesive composition contains: (meth)acrylate copolymerization The product (A) contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the copolymer; and a crosslinking agent (B), and the content of the low molecular weight component is 5 Mass% or less (Invention 1).

According to the above invention (Invention 1), even when the optical film used has been thinned compared to conventional products, it is excellent in durability when applied to a display panel, and it can be used under high temperature conditions or humid heat conditions. Suppresses the occurrence of lifting or surface peeling. In addition, the display panel using the above-mentioned optical film with an adhesive layer is less likely to cause thermal unevenness.

In the above invention (Invention 1), it is preferable that the outermost layer of the optical film that is in contact with the adhesive layer is composed of an acrylic resin layer formed by extrusion molding (Invention 2).

In the above invention (Invention 2), it is preferable that the optical film includes a retardation plate having at least the acrylic resin layer and the retardation expression layer (Invention 3).

In the above invention (Invention 3), the phase difference expression layer consists of benzene The vinyl resin is preferably constituted (Invention 4).

In the above inventions (Inventions 3 and 4), it is preferable that the phase difference plate has a second acrylic resin layer on the side opposite to the surface of the acrylic resin layer side of the phase difference expression layer (Invention 5).

In the above inventions (Inventions 3 to 5), it is preferable that a second phase difference plate is further laminated on the side opposite to the surface of the adhesive layer side of the phase difference plate (Invention 6).

In the above invention (Invention 6), it is preferable that the second retardation plate is made of cycloolefin-based resin (Invention 7).

In the above inventions (Inventions 6 and 7), it is preferable that a polarizing plate is further laminated on the side of the second phase difference plate opposite to the side of the phase difference plate side (Invention 8).

In the above invention (Inventions 1 to 8), the (meth)acrylate copolymer (A) further contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the copolymer, and the hydroxyl value is 5 to 20 mgKOH /g is preferred (Invention 9).

In the above inventions (Inventions 1 to 9), it is preferable that the crosslinking agent (B) is an isocyanate-based crosslinking agent (Invention 10).

In the above inventions (Inventions 1 to 10), it is preferable that the adhesive composition further contains a silane coupling agent (C) (Invention 11).

In the above inventions (Inventions 1 to 11), it is preferable that the adhesive composition further contains an antistatic agent (D) (Invention 12).

In the above invention (Invention 12), the antistatic agent (D) is a solid at room temperature and is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion (Invention 13).

According to the optical film with an adhesive layer of the present invention, even when the optical film has been thinned, the durability is excellent, and the display panel is less susceptible to thermal unevenness.

10A, 10B‧‧‧Optical film with adhesive layer

1‧‧‧ Adhesive layer

2A‧‧‧polarizer

2B‧‧‧Composite polarizer

21‧‧‧ Polaron

22‧‧‧The first protective layer

23‧‧‧Second protective layer

24‧‧‧First phase difference plate

241‧‧‧The first acrylic resin layer

242‧‧‧Phase difference layer

243‧‧‧The second acrylic resin layer

25‧‧‧The second phase difference plate

26‧‧‧ 2nd adhesive layer

27‧‧‧Protective layer

FIG. 1 is a cross-sectional view of an optical film with an adhesive layer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an optical film with an adhesive layer according to another 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 diagram (color) showing the evaluation criteria of the heat resistance unevenness test (visual observation) of the optical film with an adhesive layer.

Hereinafter, embodiments of the present invention will be described.

The optical film with an adhesive layer of this embodiment is configured to include an optical film and an adhesive layer laminated on at least one side of the optical film. The surface of the optical film that is in contact with the adhesive layer is composed of an acrylic resin, and the adhesive layer is composed of an adhesive obtained from an adhesive composition (hereinafter, sometimes referred to as "adhesive composition P"). The sexual composition contains: (meth)acrylate copolymer (A) containing alicyclic structure-containing monomer (a1) and aromatic ring-containing monomer (a2) as monomer units constituting the copolymer; and crosslinking agent ( B), and the content of the low molecular weight component is 5 mass% or less. In addition, in this specification, (meth)acrylate means both acrylate and methacrylate. Other similar terms The same is true.

The above-mentioned optical film with an adhesive layer even when the optical film used has been thinned compared to conventional products, when it is applied to a display panel, under durable conditions (including as exemplified in the test examples described later) Under high temperature conditions, humid heat conditions or thermal shocks, it also includes high temperature environments or humid heat environments during actual use, etc. Unless otherwise mentioned, the following is the same.), can also suppress the occurrence of warping or surface peeling. In addition, the display panel using the above-mentioned optical film with an adhesive layer is less likely to cause thermal unevenness.

Here, most of the optical films include a functional expression layer expressing optical properties such as polarization performance and phase difference performance, and a protective layer for protecting the functional expression layer and maintaining morphological stability (for morphological retention). The inventors found that by using an acrylic resin for the protective layer, it is possible to make the film thin without reducing the optical performance of the functional expression layer. However, in the conventional optical film with an adhesive layer, when an acrylic resin is used for the protective layer and the film is thinned, the shape retention under endurance conditions is insufficient, and the adhesion to the adhesive layer is also insufficient Insufficient, as a result, the optical film with an adhesive layer using the optical film fails to satisfy both durability and heat resistance unevenness. Compared to this, in the optical film with an adhesive layer of this embodiment, the stress relaxation of the adhesive layer is improved by the aforementioned composition, thereby eliminating the residue of the adhesive layer based on the shrinkage of the optical film under durable conditions stress.

In addition, regarding the insufficient adhesion between the protective layer made of acrylic resin and the adhesive layer, the inventors keenly observed the interface between the protective layer and the adhesive layer after the durability test. There is a disadvantage that a certain component is sucked out from the adhesive layer to the protective layer side. From what was discovered The phenomenon infers that under durable conditions, the low molecular weight components in the adhesive layer are attracted to the protective layer side, so that the above low molecular weight components exist on the interface between the protective layer and the adhesive layer. Because they are low molecular weight, they play like lubrication The oil-like effect, so that the tightness of the interface decreases. Based on this conclusion, the glass transition temperature (Tg) of the main polymer of the adhesive layer is increased by the aforementioned composition, and the content of the low molecular weight component is suppressed to 5 mass% or less, thereby making it difficult to make the low molecular weight under durable conditions The component is attracted from the adhesive layer to the optical film (the part made of acrylic resin), and even if it is attracted, the amount is very small, so it can be prevented from acting like a lubricant.

〔Adhesive layer〕

(1) (Meth)acrylate copolymer (A)

The (meth)acrylate copolymer (A) in this embodiment contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the copolymer. The adhesive obtained by containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2) can have appropriate cohesion and stress relaxation, and the adhesion to the acrylic resin is improved, so When used in a display panel, it can exhibit excellent durability, warpage suppression properties, and heat resistance unevenness.

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

Here, by ensuring the cross-linking point and maintaining a high cohesion From the viewpoint of the durability of the obtained adhesive being excellent, the (meth)acrylate copolymer (A) preferably has a hydroxyl value of 5 mgKOH/g or more, particularly preferably 8 mgKOH/g or more, and 10 mgKOH/g. The above is further preferred. On the other hand, from the viewpoint of making the adhesive obtained by preventing the crosslinking points from becoming excessively excellent in durability and heat resistance unevenness, the hydroxyl value is preferably 30 mgKOH/g or less. Considering the viewpoint of the warpage suppression property of the display panel at high temperature, 20 mgKOH/g or less is particularly preferable, and 16 mgKOH/g or less is even more preferable.

In addition, the acid value of the (meth)acrylate copolymer (A) is preferably 5 mgKOH/g or less, particularly preferably 2 mgKOH/g or less, and still more preferably 1 mgKOH/g or less. When the acid value of the (meth)acrylate copolymer (A) is 5 mgKOH/g or less, even if the adhesive is applied to an object that will cause defects due to acid, such as tin-doped indium oxide (ITO) and other transparent In the case of a conductive film, a metal film, etc., it is also possible to suppress such defects caused by acid. In particular, when the object to be attached 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. In addition, the smaller the lower limit value of the acid value of the (meth)acrylate copolymer (A), the better, and the range of 0 mgKOH/g is particularly preferable.

Here, the hydroxyl value and the acid value in this specification are basically set to the theoretical value derived from the blending ratio of the (meth)acrylate copolymer (A). When the theoretical value cannot be derived, the measurement is based on JIS K0070. Value.

The (meth)acrylate copolymer (A) contains an alkyl (meth)acrylate having 1 to 20 carbon atoms as the monomer unit constituting the copolymer, thereby showing better adhesion . Examples of the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate Ester, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylic acid 2 -Ethylhexyl ester, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, (methyl ) Cetyl acrylate, octadecyl (meth) acrylate, etc. Among them, from the viewpoint of further improving adhesion, (meth)acrylates having 1 to 8 carbon atoms in the alkyl group are preferred, and n-butyl (meth)acrylate or 2-ethyl (meth)acrylate Ghexyl ester is particularly preferred. In addition, these can be used alone or in combination of two or more.

(Meth) acrylate copolymer (A) It is preferable to use a (meth)acrylate alkyl ester having 1 to 20 carbon atoms containing 40 to 97.5% by mass of an alkyl group as the monomer unit constituting the copolymer In particular, it is preferably 55 to 94% by mass, more preferably 65 to 83% by mass. If 40% by mass or more of (meth)acrylic acid alkyl ester is contained, (meth)acrylic acid ester copolymer (A) can be given suitable adhesiveness. In addition, by setting the alkyl (meth)acrylate to 97.5% by mass or less, it is possible to introduce a required amount of other monomer components 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 making the distance between the obtained (meth)acrylate copolymers (A) appropriate and giving the adhesive stress relaxation properties, and improving the glass transition of the obtained copolymer (A) Temperature (Tg) to prevent the low molecular weight components in the adhesive from moving to the acrylic resin side From the viewpoint of impeding adhesion, the alicyclic structure (polycyclic structure) in which the alicyclic structure is a polycyclic ring is preferred. Further considering the compatibility of the (meth)acrylate copolymer (A) with other components, it is particularly preferable that the above polycyclic structure is bicyclic to tetracyclic. In addition, from the viewpoint of providing stress relaxation in the same manner as above, the number of carbon atoms in the alicyclic structure (refers to the number of all carbon atoms in the part forming the ring, and when a plurality of rings exist independently, the total number of carbon atoms (Number) is usually 5 or more, preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms of the alicyclic structure is not particularly limited, but, as described 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, isobornyl skeleton, naphthene skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclonon Alkane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornene diene skeleton, cubic The alkane skeleton, basket skeleton, aorane skeleton, spiro ring skeleton, etc., including dicyclopentadiene skeleton (alicyclic structure carbon number: 10) and adamantane skeleton ( The number of carbon atoms of the alicyclic structure: 10) or the isobornyl skeleton (number of carbon atoms of the alicyclic structure: 7) is preferred, and those containing an isobornyl skeleton are particularly preferred.

As the above alicyclic structure-containing monomer (a1), (meth)acrylate monomers containing the above skeleton are preferred, and specific examples thereof include cyclohexyl (meth)acrylate and (meth)acrylic acid. Dicyclopentyl ester, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc., of which , Can play comparison Excellent durability of dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate or isobornyl (meth)acrylate is preferred, and isobornyl (meth)acrylate is particularly preferred. It can be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) contains an alicyclic structure containing 1 to 20% by mass from the viewpoint of the obtained adhesive exhibiting excellent durability, warpage suppression properties, and heat resistance unevenness. The monomer (a1) is preferred as a monomer unit constituting the copolymer. In addition to the above points, from the viewpoint that the obtained adhesive exhibits good reprocessing properties, it is particularly preferable to contain 2 to 15% by mass of the alicyclic structure-containing monomer (a1), and to contain 3 to 9% by mass is particularly good.

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

Examples of the aromatic ring-containing monomer (a2) include 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 Alkane-modified cresol (meth)acrylate, ethylene oxide (EO)-modified nonylphenol (meth)acrylate, etc. Among them, from the viewpoint of improving cohesion, 2-(meth)acrylic acid 2-benzene Ethyl ethyl is preferred. These can be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) preferably contains 1 to 30% by mass of an aromatic ring-containing monomer (a2) as a monomer unit constituting the copolymer, and particularly preferably contains 3 to 25% by mass. It is more preferably 12 to 22% by mass. By setting the content of the aromatic ring-containing monomer (a2) within the above range, it is possible to make all The obtained adhesive exhibits excellent durability, warpage suppression properties, and heat resistance unevenness.

In the (meth)acrylate copolymer (A), it is preferred that the monomer unit constituting the copolymer contains a hydroxyl group-containing monomer (a3). The hydroxyl group shows good reactivity with the crosslinking agent (B), and by their reaction, the (meth)acrylate copolymer (A) is crosslinked by the crosslinking agent (B). Due to this cross-linked structure, the resulting adhesive becomes excellent in durability.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (methyl) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxyalkyl (meth)acrylate, etc. 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 to 10% by mass of a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, and particularly preferably contains 1 to 5% by mass, further Preferably, it contains 2 to 4% by mass. When the content of the hydroxyl group-containing monomer (a3) is within the above range, the hydroxyl value of the (meth)acrylate copolymer (A) can easily fall within the aforementioned range, and excellent durability and heat resistance can be effectively exhibited Uniformity. In addition, when the content of the hydroxyl group-containing monomer (a3) is 4% by mass or less, the resulting display panel has excellent warpage suppression properties at high temperatures.

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

The (meth)acrylate copolymer (A) may contain monomers other than the aforementioned monomers as monomer units constituting the copolymer. In order not to hinder the reaction of the hydroxyl group of the above-mentioned hydroxyl group-containing monomer (a3) with the cross-linking agent (B), it is preferable to use a monomer that does not contain a functional group reactive with the cross-linking agent (B) as the other monomer .

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

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

The weight average molecular weight of the (meth)acrylate copolymer (A) is preferably 1.3 million to 3 million, particularly preferably 1.5 million to 2.5 million, and further preferably 1.6 million to 1.9 million. When the weight average molecular weight of the (meth)acrylate copolymer (A) is 1.3 million or more, the durability of the obtained adhesive can be ensured satisfactorily. In addition, when the weight average molecular weight of the (meth)acrylate copolymer (A) is 3 million or less, the stress relaxation of the obtained adhesive can be ensured satisfactorily, and the warpage suppression property and heat resistance unevenness can be effectively exhibited. .

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

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

In the adhesive composition P, (meth)acrylate copolymer (A) may be used alone or in combination of two or more. In addition, the adhesive composition P may further contain a (meth)acrylate polymer in which the (meth)acrylate polymer does not contain an alicyclic structure-containing monomer (a1) or an aromatic ring-containing monomer ( a2) As a constituent monomer unit.

(2) Crosslinking agent (B)

The crosslinking agent (B) may be any one that can react with the functional group of the (meth)acrylate copolymer (A), and examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and amines. Based crosslinking agent, melamine based crosslinking agent, aziridine based crosslinking agent, hydrazine based crosslinking agent, aldehyde based crosslinking agent, oxazoline based crosslinking agent, metal alkoxy crosslinking agent, metal chelate Material-based crosslinking agent, metal salt-based crosslinking agent, ammonium salt-based crosslinking agent, etc.

When the (meth)acrylate copolymer (A) contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the copolymer, an isocyanate having excellent reactivity with the hydroxyl group derived from the hydroxyl group-containing monomer (a3) is used A cross-linking agent is preferred. Moreover, the crosslinking agent (B) may be used alone or in combination of two or more.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate. Cyanate; aliphatic polyisocyanate such as hexamethylene diisocyanate; alicyclic polyisocyanate such as isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. Urea body, isocyanurate body, and further adducts of reactants containing low-molecular-weight active hydrogen compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil (the above are sometimes collectively referred to as "Modified body".) etc. Among these, from the viewpoint of the durability of the obtained adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified body thereof is preferred, and has an organic group (e.g. An alkylene chain is preferred, and polyisocyanates or modified versions of isocyanate groups in which an alkylene chain having 1 to 4 carbon atoms) and an aromatic ring are particularly preferred are preferred. Specifically, xylylene diisocyanate or its modified body is more preferable, and trimethylolpropane modified xylylene diisocyanate is most preferable. The isocyanate-based crosslinking agent may be used alone or in combination of two or more.

The content of the crosslinking agent (B) in the adhesive composition P is preferably 0.01 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A). It is further preferably 0.1 to 0.4 parts by mass. By setting the content of the cross-linking agent (B) within the above range, the obtained adhesive can exhibit good cohesion and stress relaxation, and can become more excellent in durability and heat resistance unevenness. In addition, especially when the content of the crosslinking agent (B) is 0.4% by mass or less, the resulting display panel has excellent warpage suppression properties at high temperatures.

(3) Silane coupling agent (C)

In the adhesive composition P, in addition to the (meth)acrylate copolymer (A) and the crosslinking agent (B), it is also preferable to include a silane coupling agent (C). From the viewpoint of excellent durability of the obtained adhesive, it is particularly preferable to contain an epoxy group-containing silane coupling agent (C1) and/or a mercapto group-containing silane coupling agent (C2), and it is more preferable to contain an epoxy group-containing Both silane coupling agent (C1) and mercapto-containing silane coupling agent (C2).

Suitable 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 alkoxysilane group in the molecule, and with an adhesive component Those with good compatibility and light transmission, such as those that are substantially transparent.

Specific examples of the epoxy group-containing silane coupling agent (C1) include 3-glycidol such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Oxypropyltrialkoxysilane; 3-glycidoxypropylmethyl diethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and other 3-glycidoxypropyl groups Alkyldialkoxysilane; methyltri(glycidyl)silane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl) ) 2-(3,4-epoxycyclohexyl) ethyl trialkoxysilane, etc. Among them, from the viewpoint of further 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.

Suitable as a mercapto group-containing silane coupling agent (C2), an organosilicon compound having at least one mercapto group (mercapto group-containing organic group) and at least one alkoxysilane group in the molecule, and has good compatibility with the adhesive component and Has light transmission Sexuals, such as those who are substantially transparent.

Specific examples of the mercapto group-containing silane coupling agent (C2) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Mercapto-containing low molecular silane coupling agent; and mercapto-containing silane compounds (such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Etc.) Mercapto-containing oligomers such as co-condensates with alkyl-containing silane compounds (e.g. methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc.) Type silane coupling agent, etc. Among them, from the viewpoint of taking into consideration both durability and reprocessing properties, a mercapto group-containing oligomer-type silane coupling agent is preferred, and particularly preferred is a co-condensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound, further preferably 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 above-mentioned epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), for example, an acrylic silane coupling agent and a hydroxy 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 is preferably 0.01 to 5 parts by mass, and particularly preferably 0.1 to 2 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A). It is further preferably 0.2 to 1 part by mass.

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

(4) Antistatic agent (D)

It is preferable that the adhesive composition P further contains an antistatic agent (D). The optical components such as the release sheet laminated on the adhesive layer, or the polarizing plate or the composite polarizing plate are usually made of plastic materials, so the electrical insulation is high, and static electricity is easily generated when the release sheet is peeled off. When the static electricity generated in this way is left, when the polarizing plate or the composite polarizing plate is attached to the liquid crystal cell, the alignment of the liquid crystal molecules may be disturbed, and the presence of static electricity may cause problems such as attracting flying dust or dirt. Therefore, by containing the antistatic agent (D) in the adhesive composition P, the obtained adhesive (adhesive layer) can exert antistatic properties, thereby eliminating the above-mentioned problems.

The antistatic agent (D) may be any one that can impart antistatic properties to the obtained adhesive, 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 mainly composed of cations and anions and bonded by electrostatic attraction.

As the ionic compound, a nitrogen-containing onium salt, a sulfur-containing onium salt, a phosphorus-containing onium salt, an alkali metal salt, and an alkaline earth metal salt are preferred, and from the viewpoint of excellent durability of the obtained adhesive, particularly preferred is Nitrogen-containing onium salts. The nitrogen-containing onium salt is composed of An ionic compound composed of a nitrogen heterocyclic cation and its counter anion is preferred, particularly preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion, and further preferably a solid at room temperature and composed of nitrogen-containing Ionic compounds composed of heterocyclic cations and halogenated phosphate anions. According to ionic compounds that are solid at room temperature and composed of nitrogen-containing heterocyclic cations and halogenated phosphoric acid anions, both antistatic properties and durability can be achieved.

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

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, and N-octyl Pyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4-methylpyridinium hexafluorophosphate, N -Hexadecyl-4-methylpyridinium hexafluorophosphate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, etc. Among these, from the viewpoint of compatibility with (meth)acrylate copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methyl Pyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate and 1-butylpyridinium 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 is relative to The (meth)acrylate copolymer (A) is 100 parts by mass, preferably 0.1 to 15 parts by mass, particularly preferably 0.5 to 10 parts by mass, and further preferably 1 to 5 parts by mass. By setting the content of the antistatic agent (D) within the above range, the antistatic property can be effectively exhibited, and the decrease in physical properties such as optical properties and durability can be prevented.

(5) Low molecular weight components

The low-molecular-weight component in this specification means the one which does not correspond to any of the above-mentioned components (B) to (D) and has a molecular weight (weight average molecular weight in the case of a polymer) of 10,000 or less. Examples of the low molecular weight component include acrylic polymers, styrene polymers, urethane polymers, and silicones having a weight average molecular weight of 10,000 or less; hydrocarbons having a molecular weight of 1,000 or less, For example, stilbene (cis-stilbene, trans-stilbene), benzyl benzoate, stilbene, diphenyl sulfide, etc., but not limited to these.

The content of the low molecular weight component in the adhesive composition P is 5% by mass or less. Since the content of the low-molecular-weight component is 5 mass% or less, the probability of the low-molecular-weight component in the adhesive layer being sucked out to the optical film side (portion made of acrylic resin) is reduced, and even if it is sucked out, the amount is relatively small Since there are few, it can suppress that this low molecular weight component acts like lubricating oil. This improves the adhesion of the adhesive layer to the optical film, and when used in a display panel, can exhibit excellent durability.

From the above viewpoint, the content of the low molecular weight component in the adhesive composition P is preferably 3% by mass or less, particularly preferably 2% by mass or less, and further preferably 1.5% by mass or less. In addition, the lower limit of the content of the low molecular weight component in the adhesive composition P is preferably 0% by mass.

In addition, in this embodiment, by using the (meth)acrylate copolymer (A) of the aforementioned composition as the main agent of the adhesive composition P, the glass transition of the (meth)acrylate copolymer (A) is improved Temperature (Tg), thereby suppressing the attraction of the low molecular weight component from the adhesive layer to the optical film under durable conditions.

(6) Various additives

To the adhesive composition P, various additives commonly used for acrylic adhesives, such as dispersants (for example, alkylene glycol dialkyl ethers), tackifiers, antioxidants, ultraviolet absorbers, and light can be added as needed Stabilizers, softeners, fillers, refractive index modifiers, etc. In addition, some of these additives are equivalent to the aforementioned low molecular weight components. In this case, the content of the low molecular weight component in the adhesive composition P needs to be 5 mass% or less. In addition, the adhesive composition P means a component of a mixture of various components remaining in the adhesive layer as it is or in a state of being reacted, and is removed during the drying process, such as a polymerization solvent or a dilution solvent described later It is not included in the adhesive composition P.

(7) Manufacturing method of adhesive composition

The adhesive composition P can be manufactured by the following method: manufacturing a (meth)acrylate copolymer (A), combining the obtained (meth)acrylate copolymer (A) with a crosslinking agent (B), if necessary The added silane coupling agent (C), antistatic agent (D) and additives are mixed and manufactured.

The (meth)acrylate copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the copolymer by a conventional radical polymerization method. The polymerization of the (meth)acrylate copolymer (A) can be carried out by a solution polymerization method using a polymerization initiator as needed. Examples of the polymerization solvent include Ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc., can also be used in combination of two or more types.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexyl) Alkane 1-nitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile ), dimethyl 2,2'-azobis (2-methyl propionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2- Hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], etc.

Examples of the organic peroxide include benzoyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxide, di-n-propyl peroxide, and- Di-(2-ethoxyethyl) peroxydicarbonate, tertiary butyl peroxyneodecoxide, tertiary butyl peroxypivalate, (3,5,5-trimethylhexyl) Peroxide, dipropylamide peroxide, diethylamide peroxide, etc.

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

After obtaining the (meth)acrylate copolymer (A), add the crosslinking agent (B) to the solution of the (meth)acrylate copolymer (A), and if necessary, add the silane coupling agent (C), antistatic The agent (D), additives, diluting solvent, etc. are mixed well, thereby obtaining the adhesive composition P (coating solution) diluted by the solvent.

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

The concentration and viscosity of the coating solution prepared in this way are not particularly limited as long as they are within the coating range, and can be appropriately selected according to circumstances. For example, the concentration of the adhesive composition P is diluted to 10 to 40% by mass. In addition, when obtaining a coating solution, the addition of a dilution solvent or the like is not a necessary condition. As long as the viscosity of the adhesive composition P is a viscosity that can be applied, 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 a dilution solvent.

(8) Adhesive

The adhesive constituting the adhesive layer in this embodiment is obtained from the adhesive composition P described above. Specifically, it is a product obtained by crosslinking the adhesive composition P. The crosslinking of the adhesive composition P can be performed by heat treatment. In addition, the drying treatment when volatilizing the diluent solvent of the adhesive composition P or the like may be used as the heat treatment.

When performing 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 normal temperature (for example, 23°C, 50%RH) can also be set as needed. When the curing period is required, an adhesive layer having 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.

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

The crosslinking degree of the above adhesive, that is, the gel fraction is preferably 40 to 90%, particularly preferably 60 to 85%, and further preferably 73 to 78%. By making the gel fraction 40% or more, the durability of the adhesive becomes more excellent. In addition, by setting the gel fraction to 90% or less, the stress relaxation property of the adhesive agent becomes better, and the warp suppression property and heat resistance unevenness become more excellent. In addition, the measurement of the gel fraction of the adhesive is as shown in the test example described later.

(9) Physical properties of the adhesive layer

The thickness of the adhesive layer is preferably 5 to 100 μm, more preferably 10 to 60 μm, particularly preferably 10 to 50 μm, and further preferably 15 to 30 μm.

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

〔Optical Film〕

The optical film in this embodiment may be composed of a single layer or a plurality of layers. Examples of the optical film include composite polarizers such as polarizers, polarizing plates, retardation plates, and polarizing plates with retardation plates, viewing angle compensation films, brightness enhancement films, contrast enhancement films, liquid crystal polymer films, and diffusion films , Semi-transmissive reflective film, laminates, etc. Among them, the optical film containing the polarizer is suitable as the optical film with the adhesive layer-attached optical film of the present embodiment from the viewpoint of requiring the polarizer to be easily shrinkable, having large dimensional changes, and durability. In particular, a thin polarizing plate with a thinned protective layer, and the polarizing plate using the same The composite polarizer has a weak protective layer to suppress the shrinkage of polarizers and is easily contracted by heat or the like. Therefore, it is most suitable as an optical film with an adhesive layer-attached optical film according to this embodiment.

Here, the surface of the optical film that is in contact with the adhesive layer is made of acrylic resin. By using an acrylic resin in this part of the optical film, the film thickness can be reduced without losing a predetermined optical performance. When the optical film is composed of a single layer, the optical film is composed of a single layer of acrylic resin. When the optical film is composed of a plurality of layers, the outermost layer in contact with the adhesive layer is preferably composed of an acrylic resin layer formed by extrusion molding. The acrylic resin has a low adhesiveness with a conventionally known adhesive layer and low durability. However, according to the adhesive layer of the present embodiment, the adhesion to the acrylic resin is also high, and the stress relaxation property is also excellent. Therefore, the durability is also excellent under high temperature conditions, humid heat conditions, thermal shock, etc. In addition, the "acrylic resin layer formed by extrusion molding" also includes an acrylic resin layer obtained by performing extension treatment after extrusion molding.

The optical film of this embodiment is preferably provided with a phase difference plate having at least an acrylic resin layer and a phase difference expression layer. From the viewpoint of achieving both film formation and phase difference expression, the phase difference expression layer is made of styrene resin The configuration is better. In addition, it is preferable that the phase difference plate has a second acrylic resin layer on the side opposite to the surface on the acrylic resin layer side of the phase difference expression layer. In this way, by having an acrylic resin layer and a phase difference expression layer made of styrene resin, and further by having a second acrylic resin layer, it can be used in a liquid crystal display device, especially in IPS (In-Place-Switching) mode The liquid crystal display device exhibits excellent viewing angle compensation performance.

It is preferable that a second phase difference plate is further laminated on the side opposite to the surface of the adhesive layer side of the phase difference plate, and it is preferable that the second phase difference plate is made of cycloolefin-based resin. By having such a second phase difference plate, and further by having a second phase difference plate made of cycloolefin-based resin, the viewing angle compensation performance becomes more excellent.

In addition, it is preferable that a polarizing plate is further laminated on the side opposite to the side of the phase difference plate of the second phase difference plate. Thereby, a composite polarizing plate with very excellent viewing angle compensation performance can be provided.

[Specific example of optical film with adhesive layer]

1. An example where the optical film is a polarizing plate

An example of the optical film with an adhesive layer according to this embodiment when the optical film is a polarizing plate will be described with reference to FIG. 1. As shown in FIG. 1, the optical film 10A with an adhesive layer of this embodiment is configured to include: a polarizing plate 2A; and an adhesive layer 1 laminated on one side of the polarizing plate 2A (the lower side in FIG. 1) . 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 optical film 10A with the adhesive layer attached is used.

The adhesive layer 1 is composed of the adhesive obtained from the aforementioned adhesive composition P.

The polarizing plate 2A in this embodiment is configured to include: a polarizer 21; a first protective layer 22 laminated on one side of the polarizer 21 (the upper side in FIG. 1); and the other surface laminated on the polarizer 21 ( FIG. 1 is the second protective layer 23 on the lower surface). Although not shown, an adhesive layer may be interposed between the polarizer 21 and the first protective layer 22 and/or between the polarizer 21 and the second protective layer 23.

Polaron

The polarizer 21 is preferably composed of a polyvinyl alcohol resin film with a dichroic dye adsorption orientation.

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

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

The polarizer 21 as described above is preferably manufactured through the following process, which includes: uniaxial stretching of the polyvinyl alcohol-based resin film; dyeing and adsorption of the polyvinyl alcohol-based resin film with a dichroic dye 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 pigment, the uniaxial stretching may be performed before boric acid treatment or may be performed during boric acid treatment. Of course, it is also possible to perform uniaxial extension in these plural stages. Uniaxial extension It can be extended uniaxially between rollers with different peripheral speeds, or it can be extended uniaxially using hot rollers. In addition, it may be dry stretching in the atmosphere, or wet stretching in the state of being swollen with a solvent. The stretch magnification is usually about 4 to 8 times.

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

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 and dyeing is generally used. The content of iodine in the aqueous solution is usually about 0.01 to 0.5 parts by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 10 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution is usually about 20 to 40°C, and the immersion time (dyeing time) in the aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with a dichroic pigment is performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution of boric acid. The content of boric acid in the aqueous solution of boric acid is generally about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, it is preferable that the boric acid aqueous solution contains potassium iodide. The content of potassium iodide in the aqueous solution of boric acid per 100 parts by mass of water is usually about 2 to 20 parts by mass, 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 aqueous solution of boric acid is usually above 50°C, preferably 50 ~85°C.

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

The thickness of the polarizer 21 is preferably about 3 to 50 μm, and especially when thinning is required, about 3 to 15 μm is preferable.

(2) Protective layer

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

The main component of the transparent resin film constituting the first protective layer 22 is preferably selected from the group consisting of polyester resin, polycarbonate resin, acrylic resin, amorphous polyolefin resin and cellulose resin At least one resin. Among the above, the first protective layer 22 is preferably made of cellulose resin.

As the cellulose-based resin, a resin in which at least a part of hydroxyl groups in the cellulose is esterified with acetate may be a mixed ester in which a part of the hydroxyl group is esterified with acetate and a part of the hydroxyl group is esterified with another. The cellulose-based resin is preferably a cellulose ester-based resin, and more preferably an acetyl cellulose-based resin. As specific examples of the acetyl cellulose-based resin, triacetyl cellulose, diethyl cellulose, cellulose acetate propionate, Cellulose acetate butyrate etc. Examples of commercially available films made of such acetyl cellulose-based resins include "Fujitac TD80", "Fujitac TD80UF", and "Fujitac TD80UZ" manufactured by FUJIFILM Corporation; Konica Minolta Opto Products Co., Ltd. .Manufactured "KC8UX2M", "KC2UA" and "KC8UY" etc.

It is also possible to use a cellulose resin film to which an optical compensation function is given. As the optical compensation film, for example, a film containing a compound having a phase difference adjustment function in a cellulose resin; a compound having a phase difference adjustment function coated on the surface of the cellulose resin; and A film obtained by uniaxially or biaxially stretching a cellulose-based resin. Examples of commercially available optical compensation films of cellulose-based resins 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.

Among the above-mentioned cellulose-based resins, the first protective layer 22 is preferably composed of a cellulose ester-based resin, particularly preferably composed of an acetyl cellulose-based resin, and further preferably composed of tri-acetyl cellulose.

On the other hand, the main component of the transparent resin film constituting the second protective layer 23 is preferably an acrylic resin. In particular, the second protective layer 23 is composed of an acrylic resin from the viewpoint of not impairing polarizing performance and easy film formation. Better. In this case, when the adhesive layer in contact with the second protective layer 23 is a layer composed of a conventional acrylic adhesive composition, the low molecular weight component in the adhesive is sucked out, so that the second protective layer 23 and the adhesive The adhesion of the interface between the layers is reduced. However, if it is an adhesive layer formed of the adhesive composition P of this embodiment 1, by using a (meth)acrylate copolymer (A) having a glass transition temperature (Tg) as high as not to make the adhesion insufficient, and the content of the low molecular weight component is suppressed to 5 mass% or less can effectively suppress the low molecular weight components from being attracted from the adhesive layer 1 to the second protective layer 23. As a result, the adhesiveness of the adhesive layer 1 to the second protective layer 23 is improved. Therefore, the optical film 10A with an adhesive layer has excellent durability under high temperature conditions, wet heat conditions, and thermal shock.

As the acrylic resin forming the second protective layer 23, a polymer using methacrylate as a main monomer is preferred, and a copolymer on which a small amount of other comonomer components are copolymerized is particularly preferred. This copolymer can usually be obtained by polymerizing a monofunctional monomer containing methyl methacrylate and methyl acrylate under the condition that a radical polymerization initiator and a chain transfer agent coexist. In addition, the acrylic resin can copolymerize the third monofunctional monomer.

As the third monofunctional monomer copolymerizable with methyl methacrylate and methyl acrylate, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, benzene methacrylate Methacrylates other than methyl methacrylate such as esters, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate; ethyl acrylate, butyl acrylate, Acrylic esters such as cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate; methyl 2-(hydroxymethyl)acrylate, 2-(1-hydroxyethyl Hydroxyalkyl acrylates such as methyl acrylate, ethyl 2-(hydroxymethyl)acrylate and butyl 2-(hydroxymethyl)acrylate; unsaturated acids such as methacrylic acid and acrylic acid; chlorostyrene and bromine Styrene and other halogenated styrenes; vinyl toluene and α-methylstyrene and other substitutions Styrenes; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated anhydrides such as maleic anhydride and citraconic anhydride; unsaturated unsaturated nitrites such as phenylmaleimide and cyclohexylmaleimide Amines, etc. These can be used individually or in combination.

When copolymerizing a polyfunctional monomer, examples of the polyfunctional monomer copolymerizable with methyl methacrylate and methyl acrylate include ethylene glycol di(meth)acrylate and diethylene glycol di(meth)acrylate. Methacrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate and tetraethylene glycol di(meth)acrylate Radicals) acrylic esters, etc., where the terminal hydroxyl groups on both sides of ethylene glycol or its oligomer are esterified with acrylic acid or methacrylate; those whose propylene glycol or its oligomers are esterified with acrylic acid or methacrylic acid; Neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, and butanediol di(meth)acrylate, etc. who esterify the hydroxyl group of glycol with acrylic acid or methacrylate; The alkylene oxide adducts of bisphenol A, bisphenol A or the halogen substituents on both sides are esterified with acrylic acid or methacrylic acid; the polyhydric alcohols such as trimethylolpropane and pentaerythritol are acrylic acid or Methacrylic acid esterification; at the terminal hydroxyl groups of these glycidyl acrylate or glycidyl methacrylate epoxy ring-opening addition; in succinic acid, adipic acid, terephthalic acid, ortho Dicarboxylic acids such as phthalic acid, these halogen substitutes, and these alkylene oxide adducts, etc., undergo ring-opening addition of the epoxy groups of glycidyl acrylate or glycidyl methacrylate; aryl (Meth) acrylate; aromatic divinyl compounds such as divinylbenzene. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate can be preferably used.

The acrylic resin composed of such a composition may be modified by performing a reaction between functional groups of the copolymer. As the reaction, for example, a methyl alcohol group of methyl acrylate and a hydroxyl group of 2-(hydroxymethyl)methyl acrylate in a polymer chain decondensation reaction; a carboxyl group of acrylic acid and 2-(hydroxymethyl) Dehydration condensation reaction in the polymer chain between the hydroxyl groups of methyl acrylate.

The acrylic resin preferably has a glass transition temperature (Tg) of 80 to 120°C. When the glass transition temperature (Tg) of the acrylic resin is adjusted to the above range, the polymerization ratio of the methacrylate monomer to the acrylate monomer, the carbon chain length of each ester group and the The types of functional groups and the polymerization ratio of polyfunctional acrylic monomers relative to all monomers.

The acrylic resin may contain well-known additives as needed. Examples of well-known additives include lubricants, anti-caking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact resistance modifiers, and surfactants. However, as a protective film laminated on the polarizer, transparency is necessary, so it is preferable to limit the amount of these additives to a minimum.

As a method of manufacturing the acrylic resin film, any method such as a melt casting method, a melt extrusion method such as a T-die method or an inflation method, and a rolling method can also be used. Among them, in terms of obtaining a thin film with good surface properties, a method of forming a raw material resin, for example, by melt extrusion from a T-die, and contacting at least one side of the obtained thin film with a roll or a belt is to form a film: Better.

From the viewpoint of film forming properties of the film or impact resistance of the film, the acrylic resin may also contain an impact modifier, that is, acrylic rubber particles child. The acrylic rubber particles mentioned here refer to particles containing an elastic polymer mainly composed of acrylate as an essential component, and examples thereof include those obtained by making the elastic polymer into homogeneous particles, or the elastic Multilayer structure of polymer as a layer.

As an example of this elastic polymer, a cross-linked elastic copolymer containing alkyl acrylate as a main component and copolymerizing other vinyl monomers and cross-linkable monomers copolymerizable therewith may be mentioned. Examples of the alkyl acrylate as the main component of the elastic polymer include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. The alkyl group has about 1 to 8 carbon atoms. In particular, acrylates having an alkyl group having 4 or more carbon atoms can be preferably used. Examples of other vinyl monomers copolymerizable with the alkyl acrylate include compounds having a polymerizable carbon-carbon double bond in the molecule, and more specific examples include methyl groups such as methyl methacrylate. Acrylic esters; aromatic vinyl compounds such as styrene; vinyl cyanide compounds such as acrylonitrile. In addition, examples of the crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di(meth)acrylic acid. (Meth)acrylates of polyols such as esters and butylene glycol di(meth)acrylates; allyl (meth)acrylates such as allyl (meth)acrylate, divinylbenzene, and the like.

A laminate of a film composed of an acrylic resin containing no rubber particles and a film composed of an acrylic resin containing rubber particles may also be used as the protective layers 22 and 23. Acrylic resins can be easily obtained from commercially available products. For example, the trade names include SUMIPEX (manufactured by Sumitomo Chemical Co., Ltd.), ACRYPET (manufactured by MITSUBISHI RAYON CO., LTD.), and DELPET (Asahi Kasei Corporation. Manufacturing), Parapet (Manufactured by KURARAY CO., LTD), ACRYVIEWA (manufactured by NIPPON SHOKUBAI CO., LTD.), etc.

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

Here, the first protective layer 22 and the second protective layer 23 may be composed of the same kind of transparent resin film, or may be composed of different kinds of transparent resin films.

Before the protective layers 22 and 23 are bonded to the polarizer 21, an easy adhesion treatment 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 opposite to the bonding surface of the polarizer 21 may have various treatment layers such as a hard coat layer, an anti-reflection layer, and an anti-glare layer.

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

(3) Adhesive layer

As a configuration, the adhesive of the adhesive layer that can be sandwiched between the polarizer 21 and the first protective layer 22 and/or between the polarizer 21 and the second protective layer 23 can be selected according to the type and purpose of the object Use the appropriate one appropriately. Examples include solvent-based adhesives, emulsion-based adhesives, water-based adhesives, pressure-sensitive adhesives, rewet adhesives, polycondensation-based adhesives, solvent-free adhesives, film-shaped adhesives, and hot-melt adhesives. Agent.

A preferred adhesive constituting the above adhesive is an aqueous adhesive, and a representative example thereof is a polyvinyl alcohol resin as a main component. As can be water Adhesives, that is, commercially available polyvinyl alcohol resins include, for example, "KL-318" manufactured by KURARAY CO., LTD.

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

Examples of other preferable adhesives include adhesives composed of an epoxy resin composition containing an epoxy resin hardened by irradiation or heating of active energy rays. When using this adhesive, the bonding between the films can be performed by irradiating the adhesive layer sandwiched between the films with active energy rays or heating, and curing the curable epoxy resin contained in the adhesive. The curing of the epoxy resin by irradiation of active energy rays or heating is preferably carried out by cationic polymerization of the epoxy resin. In addition, the epoxy resin in this specification refers to having two or more rings in the molecule. Oxygen compounds.

From the viewpoint of weather resistance, refractive index, and cationic polymerizability, it is preferable that the epoxy resin contained in the adhesive agent, that is, the curable epoxy resin composition is an epoxy resin that does not contain an aromatic ring in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

(4) Manufacturing method of polarizing plate

The manufacturing of the polarizing plate 2A can be performed by a usual method. In the following, as an example, a manufacturing method when an aqueous adhesive is used as the adhesive will be described.

First, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surfaces of the protective layers 22 and 23. For the formation of the adhesive layer, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used. In addition, it is also possible to adopt a method of continuously supplying the polarizer 21 and the protective layers 22 and 23 such that the bonding surface of the two is inside, while casting the adhesive agent therebetween. After the adhesive is applied, heat treatment is performed as necessary to evaporate water to dry the adhesive layer.

The 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 preferable, from the viewpoint of suppressing defects such as bubbles or foreign substances during bonding In view of this, the larger one is better, and from the viewpoint of adhesion and durability, it is preferably implemented within the optimum range determined for each combination of the object 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 attaching the polarizer 21 and the protective layers 22 and 23, one or both of the bonding surfaces of the two may be subjected to corona discharge treatment, plasma treatment, and flame before forming the coating layer of the adhesive Treatment, primer treatment and anchor coating treatment are easy to follow.

After forming the adhesive layer as described above, the first protective layer 22 is bonded to one side of the polarizer 21 via the adhesive layer, and the second protective layer 23 is bonded to the other side of the polarizer 21. Thereby, the polarizing plate 2A formed by laminating 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 usually about 15 to 400 μm. From the viewpoint of meeting the thinning requirements in mobile communication applications and maintaining polarizing performance, 20 to 100 μm is preferable, and 30 to 80 μm is particularly preferable.

(5) Manufacturing method of optical film with adhesive layer

As a preferred example of the method for manufacturing the optical film 10A with an adhesive layer, first, an adhesive sheet is formed by stacking a release sheet on one or both sides of the adhesive layer formed of the adhesive composition P. Here, an example of an adhesive sheet manufactured by stacking peeling sheets on both sides of the adhesive layer is described.

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, such cross-linked films can also be used. It may also be such a laminated film.

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

When stacking release sheets on both sides of the adhesive layer, use one release sheet as the heavy peel release sheet with high peel force, and the other release sheet as the light release peel sheet with low release force. good.

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

As an example of the method for manufacturing the above-mentioned adhesive sheet, after applying a coating solution of the adhesive composition P on the peeling surface of the peeling sheet and performing a heat treatment to form a coating film, if necessary, another peeling sheet is laminated on the coating film (In such a way that the peeling surface is in contact with the coating film) or the substrate. The above coating film directly forms an adhesive layer when the curing period is not needed, and forms an adhesive layer after the curing period when the curing period is needed. The conditions for heat treatment and curing are as described above.

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

One side release sheet (light release type release sheet) was peeled from the adhesive sheet obtained as described above. Then, the second protective layer 23 of the polarizing plate 2A is overlaid on the exposed adhesive layer, and the adhesive sheet and the polarizing plate 2A are pressed. Thereby, the optical film 10A (with the release sheet attached) with the above-mentioned adhesive layer is obtained.

As another example of the method of manufacturing the optical film 10A with an adhesive layer, a solution (coating solution) containing the adhesive composition P is applied to the peeling surface of the release sheet, and heat treatment is performed to form a coating film. The second protective layer 23 of the polarizing plate 2A is superimposed on this coating film. The above coating film forms the adhesive layer 1 at intervals of the curing period when the curing period is needed, and directly forms the adhesive layer 1 when the curing period is not needed. Thereby, the optical film 10A (with the release sheet attached) with the above-mentioned adhesive layer is obtained.

2. An example where the optical film is a composite polarizer

An example of the optical film with an adhesive layer according to this embodiment when the optical film is a composite polarizing plate having a retardation plate will be described with reference to FIG. 2. As shown in FIG. 2, the optical film 10B with an adhesive layer of this embodiment is configured to include The composite polarizing plate 2B and the adhesive layer 1 laminated on one surface (the lower surface in FIG. 2) of the composite polarizing plate 2B. Although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the side of the composite polarizer 2B until the optical film 10B with the adhesive layer is used.

The adhesive layer 1 is composed of the adhesive obtained from the aforementioned adhesive composition P.

The composite polarizing plate 2B in this embodiment is configured to include: a first phase difference plate 24 in contact with the adhesive layer 1; and a second phase on the side of the first phase difference plate 24 opposite to the adhesive layer 1 side The difference plate 25; the second adhesive layer 26 sandwiched between the first phase difference plate 24 and the second phase difference plate 25; the layer deposited on the second phase difference plate 25 opposite to the side of the second adhesive layer 26 Polarizer 21 on the side: and a protective layer 27 deposited on the opposite side of the polarizer 21 from the second retardation plate 25 side. Although not shown, the adhesive layer may be sandwiched between the polarizer 21 and the protective layer 27 and/or between the polarizer 21 and the second retardation plate 25. This composite polarizing plate 2B can exhibit the viewing angle compensation performance well.

1st phase difference plate

The first phase difference plate 24 may be composed of a single layer expressing the phase difference, or may be composed of a plurality of layers including the phase difference expressing layer. The first phase difference plate 24 preferably includes, as shown in FIG. 3, a phase difference expression layer 242 and a first acrylic resin layered on one side of the phase difference expression layer 242 (the lower side in FIG. 3 ). Layer 241; and the second acrylic resin layer 243 laminated on the other surface (upper surface in FIG. 3) of the phase difference expression layer 242. From the viewpoint that the inherent birefringence is negative and easy to be thinned, it is preferable that the phase difference expression layer 242 is made of styrene-based resin. In this way, the composite polarizing plate 2B having the first retardation plate 24 is in the liquid A crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device, has excellent viewing angle compensation performance, and the first phase difference plate 24 is configured to include a first acrylic resin layer 241 and be formed of a styrene resin The phase difference expression layer 242 and the second acrylic resin layer 243. In addition, since the phase difference expression layer 242 is protected by the first acrylic resin layer 241 and the second acrylic resin layer 243 existing on both sides thereof, the first phase difference plate 24 is optical without losing the phase difference expression layer 242 Those with excellent performance, mechanical strength and chemical resistance.

In addition, when the layer of the first retardation film 24 that is in contact with the adhesive layer 1 is the first acrylic resin layer 241, the adhesive layer that is in contact with the first acrylic resin layer 241 is a conventional acrylic adhesive. In the case of the layer composed of the composition, the low-molecular-weight component in the adhesive is sucked out, so that the adhesion of the interface between the first acrylic resin layer 241 and the adhesive layer is lowered. However, if the adhesive layer 1 is formed of the adhesive composition P of this embodiment, by using a glass transition temperature (Tg) that has a high degree that does not make the adhesive force insufficient, (methyl ) The acrylate copolymer (A), and the content of the low molecular weight component is suppressed to 5% by mass or less, which can effectively suppress the low molecular weight component from being attracted from the adhesive layer 1 to the first acrylic resin layer 241. As a result, the adhesiveness of the adhesive layer 1 to the first retardation plate 24 is improved. Therefore, the optical film 10B with an adhesive layer has excellent durability under high temperature conditions, wet heat conditions, and thermal shock.

Furthermore, it is preferable that the first retardation plate 24 is given an in-plane retardation by extension. By this, the viewing angle compensation performance becomes more excellent.

The styrene resin constituting the phase difference expression layer 242 may be styrene The homopolymer of alkene or its derivatives may also be a binary or more binary 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- Dimethylstyrene, o-ethylstyrene, p-ethylstyrene and other alkylstyrene, or such as hydroxystyrene, third butoxystyrene, vinyl benzoic acid, o-chlorostyrene, Hydroxy, alkoxy, carboxyl, halogen, etc. are introduced into the benzene core of styrene such as p-chlorostyrene.

As the styrene-based resin, a terpolymer as disclosed in Japanese Patent Application Publication No. 2003-50316 or Japanese Patent Application Publication No. 2003-207640 can also be used.

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

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

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

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

Examples of (meth)acrylic resins include homopolymers of alkyl methacrylates or alkyl acrylates, and copolymers of alkyl methacrylates and alkyl acrylates. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. In addition, examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. Such (meth)acrylic resins can be used as commercially available (meth)acrylic resins. In addition, (meth)acrylic resins include those called impact-resistant (meth)acrylic resins, or those with glutaric anhydride structure or 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. Acrylic rubber particles refer to particles having rubber elasticity obtained by polymerizing in the presence of a polyfunctional monomer mainly composed of an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate.

The rubber particles may be made of a material having rubber elasticity into homogeneous particles, or may be a multilayer structure having at least one rubber elastic layer. Examples of the acrylic rubber particles with a multi-layer structure include those having rubber elasticity as described above as the core, and the periphery thereof is covered with a hard alkyl methacrylate polymer; and the hard alkyl methacrylate The ester-based polymer is used as the core, and the periphery is covered with the acrylic polymer having rubber elasticity as described above; and the periphery of the hard core is polymerized with acrylic elasticity having rubber elasticity Covered with a hard methacrylate-based polymer, etc.

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

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

As the (meth)acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243, a commercially available product in a state in which the (meth)acrylic resin and the acrylic rubber particles are mixed can be used. As examples of commercially available products of (meth)acrylic resin ((meth)acrylic resin composition) blended with acrylic rubber particles, trade names include: Sumitomo Chemical Co., Ltd. Sold "HT55X" or "TechnolloyS001" and so on.

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

The first acrylic resin layer 241 and the second acrylic resin layer The materials of 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 to 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 phase difference between the first acrylic resin layer 241 and the second acrylic resin layer 243 can be ignored. In addition, it is preferable that the thickness of the first acrylic resin layer 241 is substantially the same as the thickness of the second acrylic resin layer 243.

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

When manufacturing the first retardation plate 24, for example, the styrene-based resin and the (meth)acrylic resin composition containing rubber particles may be coextruded and then stretched. It can be extended by longitudinal uniaxial extension, tenter horizontal uniaxial extension, simultaneous biaxial extension or successive biaxial extension, etc., as long as it is extended to obtain the desired phase difference value. In addition to the above method, after the single-layer thin films (the phase difference expressing layer 242, the first acrylic resin layer 241, and the second acrylic resin layer 243) are formed separately, after thermal fusion is performed by heat accumulation, Extend its laminate.

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

The surface of the first phase difference plate 24 that is in contact with the adhesive layer 1 is composed of the first acrylic resin layer 241, and in this case, the adhesive force of the adhesive layer 1 to the first acrylic resin layer 241 is also high , Therefore, with an adhesive layer The optical film 10B is also excellent in durability under high temperature conditions, humid heat conditions, thermal shock, etc.

(2) Second phase difference plate

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

Among them, a cyclic olefin-based resin can be preferably used as the olefin-based resin. The cyclic olefin-based resin mainly contains a structural unit derived from an alicyclic olefin. As a typical example of the alicyclic olefin constituting the cyclic olefin-based resin, a norbornene-based monomer can be mentioned. Norbornene refers to a compound in which a carbon-carbon bond of norbornane becomes a double bond, and is named bicyclo[2,2,1]hept-2-ene according to the IUPAC nomenclature system. As an example of a norbornene substitute, when the double bond position of norbornene is set to the 1,2-position, a 3-substituted, 4-substituted, 4,5-disubstituted, etc. may be mentioned. Alternatively, dicyclopentadiene, dimethyl octahydronaphthalene, or the like may be used as the monomer constituting the cyclic olefin resin.

The cyclic olefin-based resin may or may not have a norbornane ring in its structural unit. Examples of norbornene-based monomers that form a cyclic olefin-based resin that does not have a norbornene ring include, for example, those having a 5-membered ring by ring opening, and representative examples include norbornene and bicyclic Pentadiene, 1- or 4-methyl norbornene, 4-phenyl norbornene, etc. When the cyclic olefin resin is a copolymer, the arrangement state of the molecules is not particularly limited, and it may be a random copolymer, a block copolymer, or a graft copolymer.

As a more specific example of the cyclic olefin-based resin, for example, a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and other monomers, or a male Modified products of polymers such as acid addition or cyclopentadiene addition, hydrogenated polymers or copolymers, addition polymers of norbornene monomers, norbornene monomers Addition copolymers of polymer and other monomers, etc. Examples of other monomers in the copolymer include α-olefins, cycloolefins, and non-conjugated dienes. In addition, the cyclic olefin-based resin may be a copolymer using one or two or more norbornene-based monomers and other alicyclic olefins.

In the above specific example, as the cyclic olefin-based resin, a resin obtained by hydrogenating a ring-opening polymer using a norbornene-based monomer can be preferably used. Such a cyclic olefin resin can be stretched to form a retardation plate, and it can also be stretched and a shrinkable film with a predetermined shrinkage ratio can be attached and subjected to heat shrinkage treatment, which has high uniformity and has A phase difference plate with a large phase difference value.

There are "ZEONEX" and "ZEONOR" sold by Zcon Corporation and "ARTON" sold by JSR CORPORATION as commercially available products (all trade names) of cyclic olefin resins using norbornene-based monomers. Wait. The cyclic olefin resin film or its stretched film can be obtained from commercially available products, for example (both under the trade name), "ZEONOR Film" sold by Zcon Corporation, and "ARTON Film" sold by JSR CORPORATION , "ESSINA" sold by SEKISUI CHEMICAL CO., LTD. etc.

In addition, the second retardation plate 25 can also be used, a film composed of a mixed resin containing two or more olefin resins, or a film composed of an olefin resin and others A film composed of a mixture of thermoplastic resins. For example, as a mixed resin containing two or more kinds of olefin resins, a mixture of the above-mentioned cyclic olefin resin and chain aliphatic olefin resin can be mentioned. When a mixed resin of an olefin-based resin and other thermoplastic resins is used, other thermoplastic resins can be appropriately selected according to the purpose. Specific examples include polyvinyl chloride resin, cellulose resin, polystyrene resin, acrylonitrile/butadiene/styrene copolymer resin, acrylonitrile/styrene copolymer resin, (methyl )Acrylic resins, polyvinyl acetate resins, polyvinylidene chloride resins, polyamide resins, polyacetal resins, polycarbonate resins, modified polyphenylene ether resins, polyphenylene terephthalate Butyl formate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, poly lanthanide resin, polyether lanthanide resin, polyether ether ketone resin, polyarylate resin, liquid crystal Resin, polyimide amide imide resin, polyimide resin, polytetrafluoroethylene resin, etc. The thermoplastic resin may be used alone or in combination of two or more. In addition, the above thermoplastic resin can also be used after any appropriate polymer modification. Examples of polymer modification include copolymerization, cross-linking, molecular terminal modification, and stereoregularity.

When a mixed resin of an olefin-based resin and another thermoplastic resin is used, the content of the other thermoplastic resin is generally about 50% by mass or less, and preferably about 40% by mass or less with respect to all resins. By setting the content of other thermoplastic resins within this range, a retardation plate having a small absolute value of photoelastic coefficient, exhibiting good wavelength dispersion characteristics, and having excellent durability, mechanical strength, and transparency can be obtained.

The olefin resin can be formed into a film by a solution casting method or a melt extrusion method. When two or more mixed resins are used for film formation, The method is not particularly limited. For example, a method of using a uniform solution obtained by stirring and mixing a resin component with a solvent at a predetermined ratio and manufacturing a film by a casting method; melting and mixing the resin component at a predetermined ratio and melting Extrusion method for making films, etc.

The film composed of the olefin-based resin may contain residual solvents, stabilizers, plasticizers, anti-aging agents, antistatic agents, ultraviolet absorbers, and the like, and may contain other components as necessary. In addition, it may also contain leveling agents to reduce surface roughness.

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

It is preferable that the second retardation plate 25 has a refractive index anisotropy that satisfies the following conditions: when the in-plane slow axis direction, the in-plane fast axis direction, and the thickness direction are respectively set to n _x , n _y and n _z, and the thickness of the film is set to d, the following formula _{(1): R e = (} n x -n y) × d (1)

Is defined as the wavelength of in-plane retardation value of R _e when 590nm 30 ~ 150nm, and represented by the following formula (2): Nz coefficient _{= (n x -n z) /} (n x -n y) (2)

The defined Nz coefficient exceeds 1, and is less than 2.

The second retardation film 25 having the above-mentioned refractive index anisotropy can be obtained by longitudinal uniaxial stretching of the film composed of the olefin-based resin, transverse uniaxial stretching of the tenter, simultaneous biaxial stretching, or successive biaxial stretching It can be obtained by stretching, etc., and various temperatures such as preheating temperature, stretching temperature, thermosetting temperature, cooling temperature, etc. at the time of stretching can be appropriately adjusted by appropriately adjusting the stretching ratio and stretching speed And its mode to obtain the desired refractive index anisotropy.

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

(3) The second adhesive layer

As the adhesive constituting the second adhesive layer 26, a known adhesive may be used, which may be a curable adhesive or a non-curable adhesive, but from the viewpoint of suppressing dimensional change 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 may be a polymer having active energy ray-curable polymer as a main component, or a multifunctional monomer and a polymer having no active energy ray-curable polymer and active energy ray-curable and And/or a mixture of oligomers as the main component. In addition, it may be a mixture of an active energy ray-curable polymer and an active energy ray-curable polymer, or it may be an active energy ray-curable polymer and an active energy ray-curable multifunctional monomer. And/or the mixture of oligomers may also be a mixture of these three types.

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

As a polymer without active energy ray hardening, it does not A (meth)acrylate polymer having an active energy ray-curable group (hereinafter referred to as "(meth)acrylate polymer (X)") is preferred. The (meth)acrylate polymer (X) is preferably an alkyl (meth)acrylate having an alkyl group and 1 to 20 carbon atoms as the monomer constituting the polymer. Thereby, the obtained adhesive can exhibit better adhesiveness. In addition, (meth)acrylate polymer (X) series, alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group, monomers with reactive functional groups (including reactive functional group monomers) Copolymer), and copolymers of other monomers used as needed are particularly preferred. By making the (meth)acrylate polymer (X) contain a reactive functional group-containing monomer as the monomer constituting the polymer, the adhesion to the glass surface of the liquid crystal cell or the like can be improved. It reacts with a crosslinking agent (Z) described later to form a crosslinked structure.

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

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

Examples of the reactive functional group-containing monomer include monomers having a hydroxyl group in the molecule (hydroxyl-containing monomer), monomers having a carboxyl group in the molecule (carboxyl-containing monomer), and those having an amine group in the molecule. Monomer (containing amine group monomer), etc. These reactive functional group-containing monomers may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-(meth)acrylic acid. Hydroxybutyl (meth)acrylate such as hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like.

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 and n-butylaminoethyl (meth)acrylate. 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. Preferably, it contains 2 to 5% by mass.

(Meth)acrylate polymer (X) can be polymerized It can also be a block copolymer.

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

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

As an active energy ray-curable polyfunctional monomer (hereinafter sometimes referred to as "active energy ray-curable compound (Y)"), (meth)acrylate polymer (X) and the like have excellent compatibility and molecular weight Polyfunctional acrylate monomers of 1000 or less are preferred.

Examples of multifunctional acrylate monomers with a molecular weight of 1000 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 di(meth) Group) acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, 2-functional types such as di(acryloyloxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri( Methacrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri-(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tri( 3-functional types such as acryloyloxyethyl) isocyanurate and ε-caprolactone modified tris(2-(meth)acryloyloxyethyl) isocyanurate; diglycerol Base) acrylate, pentaerythritol tetra(meth)acrylate, etc. 4 Functional type; propionic acid modified dipentaerythritol penta (meth) acrylate and other 5 functional types; di pentaerythritol hexa (meth) acrylate, caprolactone modified di pentaerythritol hexa (meth) acrylate and other 6 functional types . These can be used alone or in combination of two or more.

The content of the active energy ray-curable compound (Y) is preferably 1 to 50 parts by mass relative to 100 parts by mass of the (meth)acrylate polymer (X), particularly preferably 5 to 30 parts by mass, further preferably It is 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-containing monomer and a crosslinking agent (Z) as monomer units constituting the polymer, if the adhesive When the agent is heated, the crosslinking agent (Z) reacts with the reactive functional group of the reactive functional group-containing monomer constituting the (meth)acrylate polymer (X). Thereby, the structure in which the (meth)acrylate polymer (X) is cross-linked by the cross-linking agent (Z) is formed, and the cohesive force of the obtained adhesive agent is improved.

The crosslinking agent (Z) may be any one that reacts with the reactive functional group possessed by the (meth)acrylate polymer (X), and examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, Amine-based crosslinking agent, melamine-based crosslinking agent, aziridine-based crosslinking agent, hydrazine-based crosslinking agent, aldehyde-based crosslinking agent, oxazoline-based crosslinking agent, metal alkoxide-based crosslinking agent, metal chelate Compound-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking agent, etc. As the isocyanate-based crosslinking agent, the same as the aforementioned 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 cross-linking agent (Z), relative to (meth)acrylate poly 100 parts by mass of the compound (X) is preferably 0.01 to 10 parts by mass, particularly preferably 0.05 to 5 parts by mass, even more preferably 0.1 to 1 part by mass.

The above-mentioned active energy ray-curable adhesive may contain various additives as needed, for example: photopolymerization initiator, silane coupling agent, refractive index adjuster, antistatic agent, tackifier, antioxidant, ultraviolet absorber, light stabilizer Agents, softeners, fillers, etc.

When ultraviolet light is used as the active energy ray for curing the active energy ray-curable adhesive, the active energy ray-curable adhesive preferably contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin 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-hydroxycyclohexylphenyl 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, dichlorodi Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-third-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethyl Aminoaminobenzoate, oligomeric [2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide and so on. These can be used alone or in combination of two or more.

The photopolymerization initiator is 0.1 parts relative to 100 parts by mass of the active energy ray-curable compound (Y) in the active energy ray-curable adhesive. The amount in the range of ~20 parts by mass is preferably used, and particularly preferably 1-12 parts by mass.

In addition, from the viewpoint of improving the adhesion of the obtained adhesive to the film, the active energy ray-curable adhesive preferably contains a silane coupling agent. As a silane coupling agent, it is an organosilicon compound having at least one alkoxysilane group in the molecule, and it is preferably compatible with the adhesive component and having light transmittance.

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

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

In addition, the polymer system having the above-mentioned active energy ray-curing property, a (meth)acrylate (co)polymer having a functional group (active energy ray-curing group) having active energy ray hardening introduced into the side chain is preferred good.

The thickness of the second adhesive layer 26 is usually about 1 to 50 μm, which is The best is 1-20 μm, and the best is 2-7 μm. If the adhesive layer is too thin, the adhesiveness will decrease, while if it is too thick, it will be easy to cause bad conditions such as the adhesive being squeezed out.

(4) Polarizer

As the polarizer 21, the same polarizer 21 as the polarizer 2A described above can be used.

(5) Protective layer

The protective layer 27 is preferably made of a transparent resin film. As the protective layer 27, the same as the first protective layer 22 of the polarizing plate 2A can be used.

(6) Adhesive layer

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

(7) Manufacturing method of composite polarizing plate

The production of the composite polarizing plate 2B can be performed by a usual method. In the following, as an example, a manufacturing method when an aqueous adhesive is used as the adhesive will be described.

First, a coating film of the adhesive constituting the second adhesive layer 26 is formed on the peeling surface of the peeling sheet. Specifically, the coating liquid of the adhesive constituting the second adhesive layer 26 is applied to the peeling surface of the peeling sheet and dried.

On the other hand, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surface of the second retardation plate 25 and the protective layer 27. The adhesive layer can be formed by the same method as the manufacturing method of the polarizing plate 2A. In addition, the thickness of the adhesive layer and easy adhesion treatment are also the same.

After forming the adhesive layer as described above, The protective layer 27 is bonded to one side of the polarizer 21, and the second retardation plate 25 is bonded to the other side of the polarizer 21, thereby obtaining a buildup composed of the protective layer 27, the polarizer 21, and the second retardation plate 25 body.

Next, on the surface of the obtained laminated body on the second retardation plate 25 side, a coating film of an adhesive that constitutes the second adhesive layer 26 on the release sheet is bonded. Then, the active energy ray is irradiated through the peeling sheet to harden the coating film of the adhesive, and this coating film is used as the second adhesive layer 26.

Among them, the active energy ray refers to those having energy quanta in electromagnetic waves or charged particle beams, and specific examples include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays that are easy to handle are particularly preferred.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a metal halide lamp, a molten H lamp, a xenon lamp, etc. The irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW/cm ² . In addition, the light amount is preferably 50 to 10000 mJ/cm ² , more preferably 80 to 5000 mJ/cm ² , and particularly preferably 100 to 1000 mJ/cm ² . On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

Finally, the release sheet is peeled off from the second adhesive layer 26 formed as described above, and the surface of the first phase difference plate 24 on the second acrylic resin layer 243 side is bonded to the exposed second adhesive layer 26 . Thus, a composite polarizing plate 2B formed by laminating the protective layer 27, the polarizer 21, the second retardation plate 25, the second adhesive layer 26, and the first retardation plate 24 is obtained.

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

(8) Manufacturing method of optical film with adhesive layer

As a preferred example of the method for manufacturing the optical film 10B with an adhesive layer, first, an adhesive sheet formed by peeling off the sheet on one side or two areas of the adhesive layer formed of the adhesive composition P is manufactured. Here, as an example, an adhesive sheet manufactured by peeling off a two-area layer of an adhesive layer is produced. This adhesive sheet can be manufactured by the method described in the manufacturing method of the optical film 10A with an adhesive layer attached.

One side release sheet (light release type release sheet) was peeled from the adhesive sheet obtained as described above. Then, the first phase difference plate 24 of the composite polarizing plate 2B is overlaid on the exposed adhesive layer, and the adhesive sheet and the composite polarizing plate 2B are pressed. Thereby, the above-mentioned optical film 10B with an adhesive layer (with a release sheet) can be obtained.

As another example of the method of manufacturing the optical film 10B with an adhesive layer, the coating solution of the adhesive composition P is applied to the peeling surface of the release sheet, and after heat treatment to form a coating film, the composite polarizing plate 2B The first phase difference plate 24 overlaps the coating film. The above coating film forms the adhesive layer 1 at intervals of the curing period when the curing period is needed, and directly forms the adhesive layer 1 when the curing period is not needed. Thereby, the above-mentioned optical film 10B with an adhesive layer (with a release sheet attached) is obtained.

3. Physical properties of optical film with adhesive layer

The adhesive force of the optical films 10A and 10B with an adhesive layer of this embodiment to an alkali-free glass is preferably 0.5 to 20 N/25 mm, and particularly preferably 1 to 10 N/25 mm. By this, the optical film with the adhesive layer becomes excellent in durability. Furthermore, from the viewpoint of being excellent in reprocessing, the above-mentioned adhesive force is preferably 2 to 7 N/25 mm. In addition, the adhesive force mentioned here refers to the adhesive force basically measured in accordance with JIS Z0237:2009 by the 180° peeling method. It is determined as follows: set the measurement sample to 25 mm wide and 100 mm long, apply the measurement sample at 0.5 MPa, 50° C. for 20 minutes, and then attach it to the subject, under normal pressure, 23° C., and 50% RH It was left for 24 hours, and then measured at a peeling speed of 300 mm/min. By making the adhesive force within the above range, when sticking to the liquid crystal cell, it is possible to prevent lifting and peeling of the surface.

In addition, the adhesive film-attached optical films 10A and 10B of the present embodiment, after being attached to the above-mentioned object, are further placed under 23°C and 50% RH conditions for 14 days (adhesive 14 The adhesive force of Tin Hau) is preferably 1~20N/25mm, especially 3~9N/25mm. In this way, it is possible to suppress the increase in the adhesive force with time, whereby the adhesive film-attached optical films 10A and 10B of the present embodiment are also excellent in reprocessing property, and can be easily reattached after being attached to the liquid crystal cell.

In addition, the adhesive film-attached optical films 10A and 10B of this embodiment are self-adhesive to the above-mentioned object and have an adhesive force after being placed under the conditions of 50°C and 50% RH for 2 days (sticking at 50°C) (Adhesion after 2 days) 1 to 20N/25mm is preferable from the viewpoint of durability, and 6 to 12N/25mm is particularly preferable when further considering reprocessing properties.

The surface resistivity of the adhesive layer of the optical films 10A and 10B with an adhesive layer of this embodiment is preferably 1.0×10 ¹² Ω/sq or less, and particularly preferably 5.0×10 ¹¹ Ω/sq or less, further comparing It is preferably 5.0×10 ¹⁰ Ω/sq or less. By making the surface resistivity equal to or lower than the above value, it is possible to exert sufficient antistatic properties in the display panel. This surface resistivity can be achieved by making the adhesive composition P contain the antistatic agent (D). In addition, the measurement of the surface resistivity of the adhesive layer is carried out in accordance with JIS K6911, and specifics are shown in the test examples described later. In addition, the lower limit value of the 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 resistance unevenness.

4. Use of optical film with adhesive layer

By using the optical films 10A and 10B with an adhesive layer attached, a liquid crystal display device including, for example, a liquid crystal cell and an optical film (polarizing plate or composite polarizing plate) can be manufactured.

Specifically, the adhesive layer (the adhesive layer exposed after peeling off the peeling sheet when the peeling sheet is laminated) of the optical films 10A and 10B with the adhesive layer is laminated on the desired surface of the liquid crystal cell and Just press it. Thereby, a liquid crystal display device including the liquid crystal cell and the polarizing plate 2A and/or the composite polarizing plate 2B can be obtained.

The adhesive layer 1 of the optical films 10A and 10B with an adhesive layer according to this embodiment has excellent durability. Even if the resulting liquid crystal display device is placed under high temperature conditions, humid heat conditions or thermal shock, It is possible to suppress the interface of the adhesive layer 1 from lifting or peeling. For example, when the glass plate with the optical film 10A and 10B attached with an adhesive layer is placed under a high temperature condition of 85°C or a humid heat condition of 60°C and 90%RH for 250 hours, or -35°C is applied In the case of a thermal shock of ~70°C (30 minutes each, 200 cycles), the occurrence of warpage or surface peeling can be suppressed.

In addition, the adhesive layer 1 of the optical films 10A and 10B with an adhesive layer according to the present embodiment is also excellent in stress relaxation, and the resulting liquid crystal display device is less likely to cause thermal unevenness. For example, when the glass plates with the optical films 10A and 10B attached with an adhesive layer are placed under high temperature conditions (for example, under conditions of 80 to 85° C.) for 250 hours, it is still difficult to produce thermal unevenness. In particular, even if the liquid crystal cell is high-definition, thermal unevenness is unlikely to occur.

There may also be a transparent conductive film on the surface of the liquid crystal cell contacted by the adhesive layer 1. Examples of the transparent conductive film include metals such as platinum, gold, silver, and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc oxide, tin-doped indium oxide (ITO), and oxide Zinc-doped indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide and other composite oxides, chalcogenides, lanthanum hexaboride, titanium nitride, titanium carbide, etc. Non-oxidized compounds and other constituents.

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

【Example】

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

[Example 1]

1. Manufacture of optical film (composite polarizer)

(1) Production of polarizer

A polyvinyl alcohol film with a thickness of 75 μm composed of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more is stretched by dry uniaxial stretching for about 5 times, and further maintained under tension at 60°C In pure water for 1 minute. After that, it was immersed in an aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.05/5/100 at 28°C for 60 seconds. 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, at 26℃ After washing with pure water for 20 seconds, it was dried at 65°C to obtain polarized photons with iodine adsorption and orientation to polyvinyl alcohol.

(2) Fabrication of a laminate including a protective layer, polarizers and a second retardation plate

Preparation of 3 parts by mass of carboxy-modified polyvinyl alcohol (manufactured by KURARAY CO., LTD, trade name "KL-318") was dissolved in 100 parts by mass of water, and 1.5 parts by mass of water-soluble epoxy was added to this aqueous solution A resin, that is, an epoxy-based adhesive obtained from a polyamide epoxy additive (manufactured by Taoka Chemical Co., Ltd., trade name "Sumirez Resin 650 (30)", an aqueous solution with a solid content concentration 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 25 μm-thick triacetyl cellulose film (manufactured by Konica Minolta Opto Products Co., Ltd., trade name “KC2UA”) with a saponification surface bonded to it was used as A protective layer to obtain a layered body formed by laminating a protective layer and polarizers.

Next, on the other surface of the polarizer of the laminate, an epoxy adhesive was applied in the same manner as above, and a phase retardation composed of a cyclic olefin resin with a thickness of 23 μm was laminated on the coating layer. A thin film (manufactured by Zeon Corporation, trade name "ZEONOR") is used as the second retardation plate. After that, it was dried at 80° C. for 5 minutes, whereby the protective layer and the second retardation plate were adhered to the polarizer. After that, curing was carried out at 40°C for 168 hours to obtain a total thickness of 63 μm made up of a laminated protective layer (layer thickness 25 μm), polarizers (elongation magnification 5 times, layer thickness 15 μm) and a second retardation plate (layer thickness 23 μm) Layered body.

(3) Formation of coating film of active energy ray hardening adhesive

95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid were copolymerized to prepare a (meth)acrylate polymer (X). The molecular weight of this (meth)acrylate polymer (X) was measured by the method described later, 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) (multifunctional monomer), tris(acryloyloxyethyl)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, as a polymerization initiator, a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone mixed in a mass ratio of 1:1 (manufactured by Chiba Specialty Chemicals, commercial 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 a coating solution of active energy ray hardening adhesive.

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

(4) Fabrication of the first phase difference plate

A methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "TechnolloyS001") containing approximately 20% by mass of acrylic rubber particles constituting the first acrylic resin layer with an average particle diameter of 200 nm and a phase difference About 20 masses of styrene-maleic anhydride copolymer resin (NOVA Chemicals Corporation., trade name "DYLARK D332") and acrylic rubber particles having an average particle diameter of 200 nm constituting the second acrylic resin layer % Of methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "TechnolloyS001"), three-layer co-extrusion is performed in this order to obtain a laminated film with a three-layer structure. The obtained laminated film was stretched to obtain a first retardation plate (first acrylic resin layer/retardation expression layer/second acrylic resin layer) with an in-plane retardation value of 60 nm and a thickness of 25 μm.

(5) Fabrication of composite polarizer

To the surface of the layered body obtained by the above process (2) on the second retardation plate side, a coating film of the active energy ray-curable adhesive obtained by the above process (3) is pasted through the release sheet as follows Irradiation of ultraviolet light under the conditions hardens the coating film of the above-mentioned adhesive to become the second adhesive layer. Then, after peeling off the release sheet from the obtained second adhesive layer, the second acrylic layer of the first retardation plate obtained by the above process (4) is bonded to the surface of the exposed second adhesive layer The surface on the resin layer side. In this way, a composite polarizing plate (optical film) with a total thickness of 93 μm formed by laminating a protective layer, polarizers, a second retardation plate, a second adhesive layer, and a first retardation plate was obtained. In addition, the thickness of the formed second adhesive layer was 5 μm.

<UV irradiation conditions>

‧Using high-pressure mercury lamps

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

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

2. Manufacture of optical film with adhesive layer

(1) Preparation of (meth)acrylate copolymer

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

(2) Preparation of adhesive composition

100 parts by mass of (meth)acrylate copolymer (A) obtained in the above process (1) and trimethylolpropane as crosslinking agent (B) were modified with xylylene diisocyanate (Mitsui Chemicals, Inc .Manufactured under the trade name "TAKENATE D110N") 0.2 parts by mass as 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical CO., Ltd., as an epoxy-containing silane coupling agent (C1), Trade name "KBM403") 0.2 parts by mass, a co-condensate of 3-methylpropyltrimethoxysilane and methyltriethoxysilane containing a mercaptosilane coupling agent (C2) (Shin-Etsu Chemical CO., Manufactured by Ltd., trade name "X-41-1810", mercapto equivalent: 450 g/mol) 0.2 parts by mass, and N-octyl-4-methylpyridinium hexafluorophosphate as an antistatic agent (D) (Ionic compound that is solid at room temperature) 2.0 parts by mass are mixed and after fully stirred, It was diluted with ethyl acetate to obtain a coating solution of the adhesive composition. In addition, in this example, low molecular weight components other than the above are not blended.

Here, Table 1 shows each blending (solid content conversion value) of the adhesive composition when the (meth)acrylate copolymer (A) is 100 parts by mass (solid content conversion value). In addition, the details of the abbreviations etc. described in Table 1 are as follows.

[(Meth)acrylate copolymer]

BA: n-butyl acrylate

IBXA: isobornyl acrylate

PhEA: 2-phenylethyl acrylate

HEA: 2-hydroxyethyl acrylate

CHA: cyclohexyl acrylate

MA: methyl acrylate

[Isocyanate crosslinking agent]

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

TDI: Trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry CO., Ltd., trade name "CORONATE L")

[Antistatic agent]

Pry+PF6-(1): N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound that is solid at room temperature)

Pry+PF6-(2): N-butyl-4-methylpyridinium hexafluorophosphate (ionic compound that is solid at room temperature)

Pry+PF6-(3): 1-butylpyridinium hexafluorophosphate (solid at room temperature Ionic compound; manufactured by Tokyo Chemical Industry Co., Ltd.)

[Low molecular weight component]

Trans stilbene: Trans stilbene (manufactured by Tokyo Chemical Industry Co., Ltd.)

Benzyl benzoate: Benzyl benzoate (manufactured by Wako Pure Chemical Industries, Ltd.)

Acrylic polymer (1): an acrylate copolymer with a weight average molecular weight (Mw) of 10,000 copolymerized by 70 parts by mass of n-butyl acrylate and 30 parts by mass of 2-phenylethyl acrylate

Acrylic polymer (2): an acrylic polymer having a weight average molecular weight (Mw) of 3000 (manufactured by TOAGOSEI CO., LTD., trade name "ARUFON UP-1000").

(3) Fabrication of optical film with adhesive layer

The peeling surface of a peeling sheet (manufactured by LINTEC Corporation, SP-PET3811, thickness: 38 μm) on which one side of the polyethylene terephthalate film was peeled off with a silicone-based peeling agent was coated with a knife coater After coating the coating solution of the obtained adhesive composition, it was heated at 90°C for 1 minute to form a coating film of the adhesive composition.

Next, the composite polarizer obtained by the above was laminated with the coating film so that the surface of the first acrylic resin layer of the first retardation plate was in contact with the exposed surface of the coating film, and the temperature was 23°C, 50 Cured at %RH for 7 days to obtain an optical film with an adhesive layer and an adhesive layer formed on the composite polarizing plate. In addition, the thickness of the formed adhesive layer (first adhesive layer) was 20 μm.

[Examples 2 to 24, Comparative Examples 1 to 4]

The types and proportions of the monomers constituting the (meth)acrylate copolymer (A), the weight average molecular weight (Mw) of the (meth)acrylate copolymer (A), the type and the crosslinking agent (B) The blending amount, the blending amount of the silane coupling agent (C), the kind of antistatic agent (D), and the kind and blending amount of the low molecular weight component were changed as shown in Table 1, except that it was the same as Example 1. To manufacture optical films with an adhesive layer.

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

<Measurement conditions>

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

. GPC string (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)

An adhesive sheet was produced using a release sheet (manufactured by LINTEC Corporation, SP-PET3801, thickness: 38 μm) on which one side of a polyethylene terephthalate film was peeled off with a silicone-based release agent, instead of the Examples and Comparative Examples The optical film used in the production of optical film with adhesive layer. Specifically, on the exposed coating film of the structure composed of the peeling sheet obtained in the manufacturing process of the example or the comparative example, and the coating film of the adhesive composition, The above-mentioned peeling sheet was laminated so that the peeling treatment surface side was in contact, and cured for 7 days under the conditions of 23° C. and 50% RH. By this, an adhesive sheet composed of the structure of a release sheet (SP-PET3801)/adhesive layer (thickness: 20 μm)/release sheet (SP-PET3811) was produced.

The obtained adhesive sheet was cut to a size of 80 mm × 80 mm, the adhesive layer was coated on a polyester mesh fabric (mesh fabric size 200), and its mass was weighed with a precision balance, minus The mass of the above mesh 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. After that, the adhesive was taken out, air-dried for 24 hours in an environment with a temperature of 23°C and a relative humidity of 50%, and further dried in an oven at 80°C for 12 hours. After drying, 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. The gel fraction (%) is represented by (M2/M1)×100. The results are shown in Table 2.

[Test Example 2] (Durability Evaluation)

The optical film with an adhesive layer obtained in Examples and Comparative Examples was cut to prepare a sample of 150 mm×200 mm. After peeling off the release sheet from the sample and attaching it to alkali-free glass (manufactured by Corning Incorporated, Eagle XG) via the exposed adhesive layer, the autoclave manufactured by KURIHARA was pressurized at 0.5 MPa and 50°C for 20 minutes. .

After that, it was put into the environment of the three endurance conditions as described below, and after 250 hours, the presence or absence of warping or surface peeling was confirmed with a 10-fold magnifying glass. The evaluation criteria are as follows. The results are shown in Table 2.

◎: No lifting or surface peeling was confirmed.

○: Lifting of 0.5 mm or less or surface peeling was confirmed.

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

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

<durable condition>

‧Heat resistance: 85℃ dry

‧Damp heat: 60℃, relative humidity 90%RH

70℃下各30分鐘的熱衝擊試驗，200循環 ‧HS: -35℃

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

[Test Example 3] (Evaluation of Warpage Resistance)

The optical film with an adhesive layer obtained in Examples and Comparative Examples was cut to a length of 200 mm and a width of 150 mm. Peel off the release sheet from the optical film with an adhesive layer, and attach the exposed adhesive layer to alkali-free glass (made 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. ) In the central part of the sample. The sample was left at 85°C in a dry atmosphere for 250 hours. After that, take it out in an environment of 25°C and 50% RH, place the polarizing plate side up on the water platform, and measure the amount of warpage (distance between the corner and the stage) of each corner (4 points) of the sample from the stage ), the warpage amount of each corner is added up. Based on the results, the warpage resistance was evaluated as follows. The results are shown in Table 2.

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

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

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

×: The total amount of warpage exceeds 20 mm

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

The optical film with an adhesive layer obtained in Examples and Comparative Examples was adjusted to a size of 200 mm×150 mm using a cutting device (Super Cutter PN1-600 manufactured by Ogino Seisakusho Co., Ltd.). After peeling off the release sheet and attaching it to alkali-free glass (manufactured by Corning Incorporated, Eagle XG) via the exposed adhesive layer, the autoclave manufactured by KURIHARA was pressurized at 0.5 MPa and 50° C. for 20 minutes. In addition, the above-mentioned bonding is performed on the front and back surfaces of the alkali-free glass so that the polarizing axis of the optical film with the adhesive layer is orthogonally polarized (polarizing axis: ∠45°, ∠135°). In this state, after being left in a dry environment at 80°C for 250 hours, and then left 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 . The results are shown in Table 2.

<Evaluation method>

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

◎: The brightness distribution is roughly uniform.

○: There are some distortions in the brightness distribution on the four sides.

△: 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 Adhesion-Reprocessing Evaluation)

A 25 mm wide and 100 mm long sample was cut out from the optical film with an adhesive layer obtained in Examples and Comparative Examples, the peeling sheet was peeled off, and attached to an alkali-free glass (made by Corning Incorporated) through the exposed adhesive layer , Eagle XG), pressurized with an autoclave manufactured by KURIHARA at 0.5MPa, 50°C for 20 minutes. Thereafter, it was left for 24 hours under the conditions of 23° C. and 50% RH, and was measured under the conditions of a peeling speed of 300 mm/min and a glass angle of 180 degrees using a tensile tester (manufactured by ORIENTEC Co., Ltd., TENSILON). Adhesion (adhesion after 1 day of attachment; N/25mm). The conditions recorded outside are measured in compliance with JIS Z 0237:2009. The results are shown in Table 2.

After leaving it under the conditions of 23° C. and 50% RH for 14 days, the adhesive force was further measured in the same manner as above (adhesive force after 14 days of attachment; N/25 mm). The difference is that, after being left under the conditions of 50° C. and 50% RH for 2 days, the adhesion is measured in the same manner as above (adhesion after 50 days at 50° C.; N/25 mm). The results are shown in Table 2.

Based on the adhesive force 14 days after the above application, the reprocessing property was evaluated according to the following criteria. The results are shown in Table 2.

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

○: The adhesive force after 14 days of application exceeds 8.8N/25mm and less than 10N/25mm

△: Adhesion force after 14 days of application is 10N/25mm or more and less than 20N/25mm

×: Adhesion after 14 days of application is 20N/25mm or more

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

The optical film with an adhesive layer obtained in Examples and Comparative Examples It was cut into a size of 50 mm×50 mm, and the obtained sample was left at a temperature of 23° C. and a humidity of 50% RH for 24 hours. Thereafter, the peeling sheet was peeled off, and on the surface of the exposed adhesive layer, the surface resistivity (Ω /sq). The results are shown in Table 2.

It can be seen from Table 2 that the optical film with an adhesive layer obtained in the examples has excellent durability and is also less likely to cause thermal unevenness. In addition, the optical film with an adhesive layer obtained in the examples is one in which the surface resistivity of the adhesive layer is low and the adverse effect on the liquid crystal cell and the like is small. Moreover, Example 1~ The optical film with an adhesive layer obtained in 22 is not easily warped even at high temperature. In addition, the adhesive film-attached optical films obtained in Examples 1 to 20 and 22 to 24 were also excellent in reprocessability.

[Industry availability]

The optical film with an adhesive layer of the present invention is suitable for laminating polarized plates or composite polarized plates that have been filmed and liquid crystal cells.

1‧‧‧ Adhesive layer

2A‧‧‧polarizer

10A‧‧‧Optical film with adhesive layer

21‧‧‧ Polaron

22‧‧‧The first protective layer

23‧‧‧Second protective layer

Claims (13)

An optical film with an adhesive layer, comprising: an optical film; and an adhesive layer laminated on at least one side of the optical film; the optical film with an adhesive layer is characterized in that the optical film is adhered to the adhesive The surface where the adhesive layer contacts is composed of acrylic resin, the adhesive layer is composed of an adhesive obtained from an adhesive composition, and the adhesive composition contains: (meth)acrylate copolymer (A) contains fat The ring structure monomer (a1) and the aromatic ring-containing monomer (a2) are monomer units constituting the copolymer; and the crosslinking agent (B), and the content of the low molecular weight component is 5 mass% or less. The optical film with an adhesive layer as described in item 1 of the patent application range, wherein the outermost layer of the optical film that is in contact with the adhesive layer is composed of an acrylic resin layer formed by extrusion molding. The optical film with an adhesive layer as described in Item 2 of the patent application range, wherein the optical film includes a phase difference plate having at least the acrylic resin layer and a phase difference expression layer. The optical film with an adhesive layer as described in item 3 of the patent application scope, in which The phase difference expression layer is made of styrene resin. The optical film with an adhesive layer as described in Item 3 of the patent application range, wherein the phase difference plate has a second acrylic resin on the side opposite to the surface of the acrylic resin layer side of the phase difference expression layer Floor. The optical film with an adhesive layer as described in item 3 of the patent application scope, wherein a second phase difference plate is further laminated on the side of the phase difference plate opposite to the side of the adhesive layer side. The optical film with an adhesive layer as described in item 6 of the patent application range, wherein the second phase difference plate is made of cycloolefin resin. The optical film with an adhesive layer as described in Item 6 of the patent application scope, wherein a polarizing plate is further laminated on the side of the second retardation plate opposite to the surface on the retardation plate side. The optical film with an adhesive layer as described in item 1 of the patent application scope, wherein the (meth)acrylate copolymer (A) further contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the copolymer , The hydroxyl value is 5~20mgKOH/g. The optical film with an adhesive layer as described in item 1 of the patent application scope, wherein the aforementioned crosslinking agent (B) is an isocyanate-based crosslinking agent. The optical film with an adhesive layer as described in item 1 of the patent scope, Among them, the aforementioned adhesive composition further contains a silane coupling agent (C). The optical film with an adhesive layer as described in item 1 of the patent application scope, wherein the adhesive composition further contains an antistatic agent (D). The optical film with an adhesive layer as described in item 12 of the patent application scope, wherein 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.

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