TWI701305B - Adhesives, adhesive sheets and optical films with adhesive layers - Google Patents

Abstract

The present invention provides an adhesive, an adhesive sheet, and an optical film with an adhesive layer that will not corrode the transparent conductive film, exhibit good antistatic properties, have excellent durability, and the display panel is not easy to warp and heat unevenness. The adhesive of the present invention is obtained from an adhesive composition. The aforementioned adhesive composition contains: (meth)acrylate copolymer (A); as a monomer unit constituting the polymer, it contains an alicyclic structure-containing monomer (a1), aromatic ring-containing monomers (a2) and hydroxyl-containing monomers (a3), the hydroxyl value is 5-20mgKOH/g, the acid value is less than 5mgKOH/g, and the weight average molecular weight is 1.3 million to 3 million; isocyanate series The crosslinking agent (B); and the antistatic agent (C), wherein the gel fraction is 62 to 90%, and the antistatic agent (C) is an ionic compound containing fluorosulfimidide as an anion.

Description

Adhesive, adhesive sheet and optical film with adhesive layer

The present invention relates to adhesives, adhesive sheets and optical films with adhesive layers, and particularly relates to adhesives, adhesive sheets, and optical films with adhesive layers that are suitable for use as polarizing plates or composite polarizers. By.

In recent years, as display panels of various electronic devices, touch panels having both a display device and an input mechanism have been frequently used. The types of touch panels mainly include resistive film type, capacitive type, optical type and ultrasonic type. The resistive film type includes analog resistive film type and matrix resistive film type, and the capacitive type includes surface type and projection type.

Among the touch panels in mobile electronic devices such as smartphones and tablet computers that have recently attracted attention, more projection-type capacitive touch panels are used. As a projection type capacitive touch panel in this 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 Protective plates such as conductive film (ITO) and tempered glass.

As an optical component constituting the above-mentioned liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell usually takes the alignment layers of the two transparent electrode substrates forming the alignment layer as the inner side, is arranged at a predetermined interval by spacers, and the periphery is sealed to sandwich the liquid crystal material between the two transparent electrode substrates. Usually, the outer sides of the two transparent electrode substrates in the liquid crystal cell are respectively adhered by an adhesive. Light plate and composite polarizing plate with phase difference plate.

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

However, in conventional adhesives such as Patent Document 1, durability is not sufficient, and floating or surface peeling may occur under high temperature conditions or under humid and hot conditions. In addition, with the thinning of mobile electronic devices in recent years, optical films such as polarizing plates have also been thinned. However, the shrinkage rate of the polarizing plate of the film due to heat is relatively high. In the conventional adhesive, warpage occurs on the display panel. . In particular, in order to improve the durability of the adhesive, when a monomer with a higher glass transition point (Tg) is copolymerized as a component of a (meth)acrylic polymer, a larger shrinkage stress is generated under heat-resistant conditions. The warpage of the display panel becomes large. It is also pointed out that due to the stress caused by the thermal shrinkage of the optical film, the optical axis of the optical film deviates, resulting in light leakage (so-called thermal unevenness).

However, optical films such as release sheets or polarizing plates and composite polarizing plates laminated with the above-mentioned adhesives are usually made of plastic materials. Therefore, the electrical insulation is high, and static electricity is likely to be generated when the peeling sheet is peeled off. If the polarizing plate or the composite polarizing plate is attached to the liquid crystal cell in the state where the static electricity generated in this way is left, it may cause confusion in the alignment of the liquid crystal molecules, and the presence of static electricity may cause problems such as attracting dust or dust.

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

【Prior Technical Literature】 【Patent Literature】

[Patent Document 1] JP 2009-242786 A

[Patent Document 2] JP 2007-316377 A

[Patent Document 3] JP 2009-155585 A

However, when the above-mentioned antistatic agent is added to the adhesive composition, there is a problem that the durability of the resulting adhesive is lower than usual. Furthermore, when the adhesive is in contact with the transparent conductive film of the transparent electrode substrate, depending on the type of antistatic agent, there is a problem that the transparent conductive film is corroded and the appearance is deteriorated. In particular, silver, copper, aluminum, etc., which are expected as conductive materials to replace ITO, have a tendency to become severely corroded.

The present invention was completed in view of the actual situation, and its purpose is to provide an adhesive that does not corrode the transparent conductive film, has good antistatic properties, is excellent in durability, is not prone to warpage of the display panel, and is not prone to thermal unevenness. , Adhesive sheet and optical film with adhesive layer.

In order to achieve the above object, first, the present invention provides an adhesive, which is obtained from an adhesive composition. The adhesive composition includes: (meth)acrylate copolymer (A) as a monomer unit constituting a polymer , Containing alicyclic Formula structure monomer (a1), aromatic ring-containing monomer (a2) and hydroxyl-containing monomer (a3), the hydroxyl value is 5-20mgKOH/g, the acid value is below 5mgKOH/g, and the weight average molecular weight is 1.3 million-300 Wan; isocyanate-based crosslinking agent (B); and antistatic agent (C), wherein the gel fraction of the aforementioned adhesive is 62 to 90%, and the aforementioned antistatic agent (C) contains fluorosulfonate as an anion Ionic compound of amine (Invention 1).

According to the above invention (Invention 1), even if it is attached to a transparent conductive film such as ITO, silver, copper, aluminum, etc., the transparent conductive film will not be corroded, exhibits good antistatic properties, excellent durability, and the display panel is not easy to warp It is not easy to produce uneven heat.

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

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

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

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

Secondly, the present invention provides an adhesive sheet provided with an adhesive layer (invention 6) composed of the aforementioned adhesive (inventions 1 to 5).

Third, the present invention provides an optical film with an adhesive layer, comprising: an optical film; and an adhesive layer, which is laminated on at least one side of the optical film and is composed of the adhesive (Inventions 1 to 5) (Invention 7).

Adhesive, adhesive sheet and optical with adhesive layer according to the present invention The thin film, even if it is attached to a new transparent conductive film (such as silver, copper, aluminum, etc.) that replaces ITO, it will not corrode the transparent conductive film, exhibits good antistatic properties, has excellent durability, and is not easy to display panels Warpage, and is not prone to heat unevenness.

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

1‧‧‧Adhesive layer

2A‧‧‧Polarizer

2B‧‧‧Composite Polarizing Plate

21‧‧‧Polarizer

22‧‧‧The first protective layer

23‧‧‧Second protection layer

24‧‧‧The first phase difference plate

241‧‧‧The first acrylic resin layer

242‧‧‧Phase Difference Expression Layer

243‧‧‧The second acrylic resin layer

25‧‧‧The second phase difference plate

26‧‧‧Second adhesive layer

27‧‧‧Protection 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 graph (color) showing the evaluation criteria of the heat non-uniformity test (visual observation) of an optical film with an adhesive layer.

Hereinafter, embodiments of the present invention will be described.

〔Adhesive〕

The adhesive of this embodiment is an adhesive obtained from an adhesive composition (hereinafter, sometimes referred to as "adhesive composition P"), and the aforementioned adhesive composition contains: (meth)acrylate copolymer (A) ), as the monomer unit constituting the polymer, contains alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2) and hydroxyl-containing monomer (a3), and the hydroxyl value is 5 (5.0 is preferred) ~20mgKOH/g, acid value below 5mgKOH/g, weight average molecular weight of 1.3 million to 3 million; isocyanate-based crosslinking agent (B); and antistatic agent (C), of which the gel fraction is 62-90 %. In addition, the antistatic agent (C) is an ionic compound containing fluorosulfonimide as an anion. In addition, in this specification, (meth)acrylate means Both acrylate and methacrylate. Other similar terms are also the same.

Even if the adhesive that meets the above requirements is attached to a new transparent conductive film that replaces ITO, such as a transparent conductive film made of silver, copper, aluminum, etc., it will not corrode the transparent conductive film and exhibit good antistatic properties. When used in a display panel, it has excellent durability and suppresses floating or surface peeling even under high temperature conditions, humid heat conditions, or thermal shock. In addition, the display panel using the above-mentioned adhesive is not prone to warpage even under high temperature conditions, and is not prone to heat unevenness.

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

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

On the other hand, if the acid value of the (meth)acrylate copolymer (A) is 5 mgKOH/g or less, even if the object to be attached to the adhesive is those that have problems due to acid, such as ITO, silver, copper, In the case of transparent conductive films such as aluminum, it can also suppress this kind of disadvantage caused by acid. That is, it is possible to suppress the phenomenon of corroding the transparent conductive film or changing the resistance value of the transparent conductive film. In addition, the aforementioned metal films such as silver, copper, and aluminum generally do not have light transmittance. However, the technology In the domain, a predetermined metal film is also used for thinning by patterning. At this time, even if it is a metal film, light is transmitted through the gap between the thin lines. Therefore, in this specification, these metal films are also classified as transparent conductive films.

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

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

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

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

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

If the gel fraction of the adhesive of this embodiment is less than 62%, the durability of the adhesive will deteriorate. In addition, if the gel fraction of the adhesive of this embodiment exceeds 90%, the stress relaxation of the adhesive of this embodiment will decrease. The display panel warps or heat unevenness occurs under high temperature conditions.

From the above viewpoint, the lower limit of the gel fraction of the adhesive of the present embodiment is preferably 65% or more, and more preferably 73% or more. In addition, the upper limit value of the gel fraction of the adhesive of the present embodiment is preferably 85% or less, and particularly preferably 78% or less. In addition, the measuring method of the gel fraction of an adhesive is as shown in the test example mentioned later.

The adhesive of the present embodiment exhibits good antistatic properties by containing the antistatic agent (C), which is an ionic compound containing fluorosulfonylimine as an anion. In addition, the antistatic agent (C) does not hinder the durability of the adhesive and does not corrode the transparent conductive film. Therefore, the adhesive containing the antistatic agent (C) can have both antistatic properties and durability, and has excellent corrosion resistance with respect to the transparent conductive film, and can maintain the appearance of the transparent conductive film well.

(1) (Meth) acrylate copolymer (A)

In the (meth)acrylate copolymer (A) of this embodiment, as monomer units constituting the polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2) and a hydroxyl group-containing monomer are contained Monomer (a3). Among these monomers, by particularly containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2), the resulting adhesive can simultaneously have appropriate cohesion and stress relaxation, and is relatively optical Since the adhesiveness of the thin film or the transparent conductive film is improved, when used in a display panel, it can exhibit excellent durability, warpage suppression properties, and heat unevenness.

In the (meth)acrylate copolymer (A), as the monomer units constituting the polymer, in addition to the above-mentioned alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2) and hydroxyl-containing monomer ( In addition to a3), an alkyl (meth)acrylate having 1 to 20 carbon atoms and further containing an alkyl group is preferred. In addition, according to needs Contains other monomers.

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

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

The carbocyclic ring of the alicyclic structure in the alicyclic structure-containing monomer (a1) may be a saturated structure or a partially unsaturated bond. In addition, fat The cyclic structure may be a monocyclic alicyclic structure, or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. From the viewpoint of making the distance between the obtained (meth)acrylate copolymer (A) appropriate and imparting stress relaxation to the adhesive, the above-mentioned alicyclic structure is a polycyclic alicyclic structure (Polycyclic structure) is preferred. Further considering the compatibility of the (meth)acrylate copolymer (A) with other components, the above-mentioned polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, from the viewpoint of imparting the same stress relaxation properties as above, the carbon number of the alicyclic structure (refers to the total number of carbons in the part forming the ring, and when multiple rings exist independently, the total number of carbons) is usually It is preferably 5 or more, particularly preferably 7 or more. On the other hand, the upper limit of the carbon number 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.

As an alicyclic structure, for example, those containing the following skeletons are mentioned. The aforementioned skeletons are cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl) skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane) Skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloolefin skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornene two Alkene skeleton, cubane skeleton, basketane skeleton, room alkane skeleton, spiro ring skeleton, etc., including dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), diamond The alkane skeleton (the carbon number of the alicyclic structure: 10) or the isobornyl skeleton (the carbon number of the alicyclic structure: 7) is preferable, and the one containing the isobornyl skeleton is particularly preferable.

As the above-mentioned alicyclic structure-containing monomer (a1), a (meth)acrylate monomer containing the above-mentioned skeleton is preferred. Specifically, cyclohexyl (meth)acrylate and (meth)acrylic acid are mentioned. Dicyclopentyl ester, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentene (meth)acrylate Ester, dicyclopentenyloxyethyl (meth)acrylate, etc., among them, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate or (meth) Isobornyl acrylate is preferred, and isobornyl (meth)acrylate is particularly preferred. These can be used alone or in combination of two or more.

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

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

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

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

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

As the hydroxyl group-containing monomer (a3), for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth) Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., among which, from the isocyanate-based crosslinking agent ( From the viewpoint of the reactivity of B), 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.

In the (meth)acrylate copolymer (A), it is preferable to contain 0.5-10% by mass of the hydroxyl-containing monomer (a3) as the monomer unit constituting the polymer, and particularly preferably 1 to 5% by mass, It is more preferable to contain 2 to 4% by mass. By setting the content of the hydroxyl-containing monomer (a3) within the above range, the hydroxyl value of the (meth)acrylate copolymer (A) can easily fall within the above range, and the excellent durability can be effectively exhibited. Warpage suppression and heat unevenness.

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

In the (meth)acrylate copolymer (A), as a monomer unit constituting the polymer, other monomers other than the aforementioned monomers may be contained. As this other monomer, in order not to hinder the reaction of the hydroxyl group of the above-mentioned hydroxyl-containing monomer (a3) with the isocyanate-based crosslinking agent (B), the monomer does not contain a functional group reactive with the isocyanate-based crosslinking agent (B). Body is better.

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

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

In the adhesive composition P, the (meth)acrylate copolymer (A) may be used alone or in combination of two or more. In addition, the adhesive composition P may also contain the following (meth)acrylate polymer, which does not contain the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2) Or a hydroxyl group-containing monomer (a3) is used as a constituent monomer unit.

(2) Isocyanate-based crosslinking agent (B)

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

Isocyanate-based crosslinking agent (B) contains at least polyisocyanate Compound persons. As the polyisocyanate compound, for example, aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; isophorone diisocyanate; Alicyclic polyisocyanates such as isocyanate, hydrogenated diphenylmethane diisocyanate, etc., in addition to these, biuret, isocyanurate, and ethylene glycol, propylene glycol, neopentyl Diol, trimethylolpropane, castor oil and other reactants containing low-molecular-weight active hydrogen compounds, that is, adducts (to sum up, sometimes referred to as "modified bodies") and so on. Among them, from the viewpoint of the durability of the resulting adhesive, aromatic polyisocyanates or modified compounds having aromatic rings are preferred, and those having an organic group (for example, preferred The alkylene chain is particularly preferably a polyisocyanate having an isocyanate group bonded to an aromatic ring or a modified product thereof, particularly preferably an alkylene chain having 1 to 4 carbon atoms. Specifically, xylylene diisocyanate or its modified version is more preferable, and trimethylolpropane modified xylylene diisocyanate is the most preferable. The above-mentioned isocyanate-based crosslinking agent (B) may be used alone or in combination of two or more.

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

(3) Antistatic agent (C)

The adhesive composition P contains an antistatic agent (C). The release sheet laminated on the adhesive layer, or the optical film such as polarizer or composite polarizer is usually made of plastic material Because of its structure, it has high electrical insulation, and it is easy to generate static electricity when peeling off the release sheet. In a state where the static electricity generated in this way remains, when a polarizing plate or a composite polarizing plate is attached to the liquid crystal cell, the alignment of the liquid crystal molecules may be disturbed. In addition, the presence of static electricity may cause problems such as attracting fly dust or dust. Here, since the adhesive composition P contains the antistatic agent (C), the resulting adhesive (adhesive layer) can exhibit antistatic properties, thereby eliminating the above-mentioned problems.

The antistatic agent (C) of this embodiment is an ionic compound containing fluorosulfimidide as an anion. The antistatic agent (C) does not hinder the durability of the adhesive formed by the (meth)acrylate copolymer (A) and the isocyanate-based crosslinking agent (B), and does not corrode the transparent conductive film. Therefore, the adhesive containing the antistatic agent (C) can have both antistatic properties and durability, and has excellent corrosion resistance with respect to the transparent conductive film, and can maintain the appearance of the transparent conductive film well. Here, the ionic compound in this specification refers to a compound in which cations and anions are mainly combined by electrostatic attraction.

The cation contained in the above-mentioned ionic compound is not particularly limited, but a nitrogen-containing heterocyclic cation is preferred. That is, the antistatic agent (C) is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a sulfonamide (anion). This ionic compound is particularly preferable from the viewpoint of antistatic properties, durability, and corrosion resistance with respect to a transparent conductive film.

As the nitrogen-containing heterocyclic skeleton of the aforementioned nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, a triazole ring, an indole ring, etc. are preferable, and a pyridine ring is preferable. In addition, the above-mentioned fluorosulfonimide-based bis(fluorosulfonyl)imine is particularly preferred.

The above-mentioned ionic compound is preferably a solid at room temperature. If it is a solid at room temperature, it will easily exhibit stable resistance even if exposed to durable conditions. Electrostatic.

Specific examples of the antistatic agent (C) include N-decylpyridine bis(fluorosulfonyl)imine, 1-ethylpyridine bis(fluorosulfonyl)imine, 1-butylpyridine Bis(fluorosulfonyl)imine, 1-hexylpyridine bis(fluorosulfonyl)imine, 1-butyl-3-methylpyridine bis(fluorosulfonyl)imine, 1-butyl-4 -Picoline bis(fluorosulfonyl) imine, 1-hexyl-3-methylpyridine bis(fluorosulfonyl) imine, 1-butyl-3,4-dimethylpyridine bis(fluorosulfonyl) Amino) imine and the like. Among these, N-decylpyridine bis(fluorosulfonyl)imide is preferable from the viewpoint of corrosion resistance to the transparent conductive film. The above antistatic agent (C) may be used individually by 1 type, and may be used in combination of 2 or more types.

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

(4) Silane coupling agent (D)

In addition to the above-mentioned components, the adhesive composition P preferably contains a silane coupling agent (D). From the viewpoint of imparting excellent durability to the resulting adhesive, it is particularly preferable to contain epoxy-containing silane The coupling agent (D1) and/or the mercapto group-containing silane coupling agent (D2) further preferably contain both the epoxy group-containing silane coupling agent (D1) and the mercapto group-containing silane coupling agent (D2).

As an epoxy-containing silane coupling agent (D1), a suitable system has at least one epoxy group (organic group containing epoxy group) and at least one alkoxy group in the molecule An organosilicon compound of a silyl group, which has good compatibility with the adhesive components and has light permeability, such as substantially transparent.

Specific examples of the epoxy-containing silane coupling agent (D1) include 3-glycidol such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane Oxypropyl trialkoxy silane; 3-glycidoxy propyl 3-glycidoxy propyl methyl diethoxy silane, 3-glycidoxy propyl methyl dioxy silane, etc. Alkyl dialkoxysilane; methyl tris(glycidyl) silane; 2-(3,4-epoxycyclohexyl) ethyl trimethoxy silane, 2-(3,4-epoxycyclohexyl) ) 2-(3,4-epoxycyclohexyl) ethyl trialkoxysilane, such as ethyl triethoxy silane, etc. Among them, from the standpoint of improving durability, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldi Ethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are preferred, and 3-glycidoxypropyltrimethoxysilane is particularly preferred. These can be used alone or in combination of two or more.

As a suitable mercapto-containing silane coupling agent (D2), it is an organosilicon compound with at least one mercapto group (organic group containing mercapto group) and at least one alkoxysilyl group in the molecule, and has good compatibility with adhesive components And have light transmittance, for example, substantially transparent.

Specific examples of the mercapto group-containing silane coupling agent (D2) include: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane And other mercapto-containing low-molecular-weight silane coupling agents; and mercapto-containing silane compounds (such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Etc.) with alkyl silicon Cocondensates of alkane compounds (e.g. methyl triethoxy silane, ethyl triethoxy silane, methyl trimethoxy silane, ethyl trimethoxy silane, etc.), such as mercapto group-containing oligomer type silane coupling agents, etc. . Among them, from the viewpoint of both durability and reworkability, the mercapto group-containing oligomer-type silane coupling agent is preferred, particularly preferably a co-condensate of mercapto-containing silane compound and alkyl-containing silane compound, and more preferably The co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane. These can be used alone or in combination of two or more.

As the silane coupling agent (D), in addition to the epoxy group-containing silane coupling agent (D1) and mercapto group-containing silane coupling agent (D2), for example, acryl-based silane coupling agent, hydroxy-based silane coupling agent can be used in combination as needed. Mixtures, carboxyl-based silane coupling agents, amino-based silane coupling agents, amide-based silane coupling agents, isocyanate-based silane coupling agents, etc.

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

In addition, the content of the epoxy-containing silane coupling agent (D1) in the adhesive composition P relative to 100 parts by mass of the (meth)acrylate copolymer (A), preferably 0.005 to 2.5 parts by mass, and particularly preferably 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass. On the other hand, the content of the mercapto-containing silane coupling agent (D2) in the adhesive composition P relative to 100 parts by mass of the (meth)acrylate copolymer (A), preferably 0.005 to 2.5 parts by mass, and particularly preferably 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass.

(5) Various additives

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

〔Method of manufacturing adhesive composition〕

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

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

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

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

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

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

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

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

The adhesive of this embodiment is obtained from the adhesive composition P described above, specifically, the adhesive composition P is crosslinked. The crosslinking of the adhesive composition P can be performed by heat treatment. In addition, the drying treatment at the time of volatilizing the diluent solvent of the adhesive composition P and the like may also be used as the heating treatment.

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

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

〔Adhesive sheet〕

The adhesive sheet of this embodiment is provided with an adhesive layer composed of the aforementioned adhesive. The peeling sheet can be layered on one side or two areas of the adhesive layer. In addition, the release sheet may be layered on one area of the adhesive layer, and the desired substrate may be layered on the other area. In addition, when the substrate is an optical film, in this specification, the adhesive sheet corresponds to an optical film with an adhesive layer to be described later.

The thickness of the adhesive layer is appropriately determined according to the purpose of use of the adhesive sheet, and is usually in the range of 5 to 100 μm, preferably in the range of 10 to 60 μm. For example, when used as an adhesive layer of an optical film, it is preferably 10 to 50 μm, particularly preferably 15 to 30 μm.

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

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

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

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

The base material is not particularly limited, and any base material sheet that is a normal adhesive sheet can be used. For example, in addition to the desired optical member (optical film), rayon, acrylic, Woven or non-woven fabric of polyester and other fibers; synthetic paper; high-quality paper, cellophane, impregnated paper, coated paper and other papers; aluminum, copper and other metal foils; urethane foam, polyethylene foam, etc. Foam; Polyester film such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyurethane film, polyethylene film, polypropylene film, three Cellulose films such as acetyl cellulose, polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, and Plastic films such as bornene resin films and cycloolefin resin films; and laminates of two or more of these. The plastic film can be formed by uniaxial stretching or biaxial stretching.

The thickness of the substrate may also vary according to its kind, but it is usually 5 to 500 μm, preferably 10 to 300 μm, and particularly preferably 20 to 150 μm.

As an example of the manufacturing method of the adhesive sheet of this embodiment, a coating solution of the adhesive composition P is applied on the release surface of the release sheet, heat-treated to form a coating film, and if necessary, a layer is laminated on the coating film Other release sheet (in a way that the release surface is in contact with the coating film) or substrate. The above coating film directly forms the adhesive layer when the curing period is not required, and when the curing period is required, the adhesive layer is formed after the curing period. The conditions for heat treatment and aging are as described above.

As a method of applying the above-mentioned coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be used.

The haze value (value measured in accordance with JIS K7136: 2000) of the adhesive layer of the adhesive sheet of this embodiment is preferably 2% or less, and particularly preferably 1% or less. If the haze value is 2% or less, the transparency is very high and it becomes suitable as a light Learners.

〔Optical film with adhesive layer〕

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 surface of the optical film. The adhesive layer is formed of the adhesive of the foregoing embodiment, or is formed of the adhesive layer of the adhesive sheet of the foregoing embodiment. The thickness and physical properties of the adhesive layer are the same as the adhesive layer of the aforementioned adhesive sheet.

The optical film may be composed of a single layer, or may be composed of multiple layers. Examples of optical films include composite polarizers such as polarizers, polarizers, retardation plates, polarizers with retardation plates, viewing angle compensation films, brightness enhancement films, contrast enhancement films, liquid crystal polymer films, and diffusion films. , Semi-transmitting reflective film, and such laminates. Among them, from the viewpoint of requiring the polarizer to be easy to shrink, large in size change, and durability, the optical film containing the polarizer is suitable as the optical film of the adhesive layer-attached optical film of this embodiment. In particular, the thin polarizing plate with the protective layer thinned and the composite polarizing plate using the polarizing plate have a weak protective layer to suppress the shrinkage of the polarizer and tend to shrink due to heat, so they are most suitable as this embodiment The optical film is an optical film with an adhesive layer.

Here, the surface of the optical film in contact with the adhesive layer may be made of acrylic resin. In addition, the outermost layer of the optical film that is in contact with the adhesive layer may also be composed of an acrylic resin layer formed by extrusion molding. The acrylic resin has low adhesion to the conventionally known adhesive layer and low durability. However, the adhesive layer according to the present embodiment has higher adhesion than acrylic resin and has excellent stress relaxation properties . Therefore, under high temperature conditions, under humid conditions, Inferior thermal shock and excellent durability. In addition, the "acrylic resin layer formed by extrusion molding" also includes an acrylic resin layer obtained by stretching after extrusion molding.

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

An example of an optical film with an adhesive layer of 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 laminated on one surface of the polarizing plate 2A (the lower surface in FIG. 1) 1. In addition, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the polarizing plate 2A side until the optical film 10A with the adhesive layer is used.

The adhesive layer 1 is formed of the adhesive of the foregoing embodiment.

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 side of the polarizer 21 ( 1 is the second protective layer 23 on the lower side. In addition, although not shown, an adhesive layer may be sandwiched between the polarizer 21 and the first protective layer 22 and/or between the polarizer 21 and the second protective layer 23.

(1) Polarizer

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

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

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

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

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

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

When iodine is used as a dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide for dyeing is usually adopted. The content of iodine in the aqueous solution is usually about 0.01 to 0.5 parts by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 10 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution is usually about 20 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 dye is performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid aqueous solution. The content of boric acid in the boric acid aqueous solution is usually about 2 to 15 parts by mass per 100 parts by mass of water, and preferably about 5 to 12 parts by mass. When 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 boric acid aqueous solution is usually about 2 to 20 parts by mass per 100 parts by mass of water, and preferably 5 to 15 parts by mass. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50°C or higher, preferably 50 to 85°C.

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

The thickness of the polarizer 21 is preferably about 3-50 μm, and especially when thinning is required, about 3-15 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 composed 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 is preferably at least one resin selected from the group consisting of polyester resin, polycarbonate resin, acrylic resin, amorphous polyolefin resin, and cellulose resin.

As the amorphous polyolefin resin used for the protective layers 22 and 23, cycloolefin resin is preferable. Examples of cycloolefin resins include norbornene or its derivatives obtained by Diels-Alder reaction from cyclopentadiene and olefins as monomers to undergo ring-opening metathesis polymerization (metathesis polymerization), followed by hydrogenation to obtain the resin; from dicyclopentadiene and olefins or methacrylates by Diels-Alder reaction to obtain tetracyclododecene (tetracyclododecene) or its Derivatives are used as monomers to undergo ring-opening translocation polymerization, followed by hydrogenation to obtain resins; use selected from norbornene, tetracyclododecene and their derivatives, and other cyclic polyolefin monomers The resin obtained by carrying out the same ring-opening translocation polymerization and then hydrogenation; using norbornene, tetracyclododecene or their derivatives and aromatic compounds with vinyl Resin etc. obtained by addition copolymerization. Examples of commercially available amorphous polyolefin resins include "ARTON" of JSR CORPORATION, "ZEONEX" and "ZEONOR" of Zeon Corporation, "APO" and "APEL" of Mitsui Chemicals, Inc., and the like. When the amorphous polyolefin resin is used as a film, the film can be Well-known methods, such as a solvent casting method and a melt extrusion method, are used suitably.

As the cellulose resin, a resin in which at least a part of the hydroxyl groups in the cellulose is esterified with acetic acid may be a mixed ester in which a part is esterified with acetic acid and a part is esterified with another. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetyl cellulose resin. Specific examples of the acetyl cellulose resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. Commercial products of films made of such acetyl cellulose resins include, for example, "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-based resin film provided with an optical compensation function. As the optical compensation film, for example, a film containing a compound having a retardation adjustment function in a cellulose resin; a film having a retardation adjustment function coated on the surface of a cellulose resin; and A film obtained by uniaxially or biaxially stretching a cellulose resin. Examples of commercially available cellulose-based resin optical compensation films include: "Wide view Film WV BZ 438" and "Wide view Film WV EA" manufactured by FUJIFILM Corporation, and manufactured by Konica Minolta Opto Products Co., Ltd. "KC4FR-1" and "KC4HR-1" etc.

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

Here, the first protective layer 22 and the second protective layer 23 can be The same type of transparent resin film can also be composed of different types of transparent resin film.

Before the protective layers 22 and 23 are bonded to the polarizer 21, easy bonding treatments such as saponification treatment, corona treatment, primer treatment, and anchor coating treatment may be performed on the bonding surface. In addition, the surface of the protective layers 22 and 23 on the side 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 further preferably 10 to 30 μm.

Among the above, the first protective layer 22 is preferably composed of cellulose resin, more preferably composed of cellulose ester resin, more preferably composed of cellulose acetate resin, and more preferably composed of triacetyl cellulose. .

The second protective layer 23 is preferably composed of an amorphous polyolefin-based resin among the above, and is particularly preferably composed of the aforementioned cycloolefin-based resin. In this case, the adhesive force of the adhesive layer 1 with respect to the second protective layer 23 is also relatively high. Therefore, the optical film 10A with the adhesive layer has durability under high temperature conditions, damp heat conditions, thermal shock, etc. Excellent.

(3) Adhesive layer

As an adhesive 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, it can be adjusted according to the type and purpose of the object Use the appropriate one appropriately. For example, solvent-based adhesives, emulsion-type adhesives, water-based adhesives, pressure-sensitive adhesives, remoisturizing adhesives, polycondensation-type adhesives, solvent-free adhesives, film-like adhesives, and hot-melt adhesives剂 etc.

A preferable adhesive agent constituting the above-mentioned adhesive agent is a water-based adhesive agent, and a representative example thereof is a polyvinyl alcohol-based resin as the main component. Examples of commercially available polyvinyl alcohol-based resins that may be water-based adhesives include "KL-318" manufactured by KURARAY CO., LTD.

The water-based adhesive may contain a crosslinking agent. As the crosslinking agent, amine compounds, aldehyde compounds, methylol compounds, epoxy compounds, isocyanate compounds, polyvalent metal salts, etc. are preferred, and epoxy compounds are particularly preferred. As a commercially available product of the crosslinking agent, there are, for example, glyoxal or "Sumirez Resin650(30)" which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Company, Limited.

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

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

(4) Manufacturing method of polarizing plate

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

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

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

When the polarizer 21 and the protective layers 22, 23 are attached, it is also possible to perform corona discharge treatment, plasma treatment, flame treatment before forming the coating layer of the adhesive on one or both sides of the bonding surface of the two. Easy to adhere to treatment, primer treatment and anchor coating treatment.

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

The total thickness of the polarizer 2A is usually about 15~400μm. From the viewpoint of thinning requirements in mobile communication applications and maintaining polarization performance, 20-100μm is preferred, and 30-80μm is particularly preferred.

(5) Manufacturing method of optical film with adhesive layer

As an example of the method of manufacturing the adhesive layer-attached optical film 10A, an adhesive sheet composed of a two-area peeling sheet on the adhesive layer is prepared as the adhesive sheet of this embodiment, and one side of the peeling sheet (light Peel type peeling sheet). Then, the second protective layer 23 of the polarizing plate 2A is stacked on the exposed adhesive layer, and the adhesive sheet and the polarizing plate 2A are pressed. Thereby, the above-mentioned optical film 10A with an adhesive layer (with a release sheet) was obtained.

As another example of the method of manufacturing the adhesive layer-attached optical film 10A, a solution (coating solution) containing the aforementioned adhesive composition P is applied to the release surface of the release sheet, and then heated to form a coating film. The second protective layer 23 of the polarizing plate 2A is superposed on this coating film. When the above-mentioned coating film requires an aging period, the aging period is separated to form the adhesive layer 1, and when the aging period is not required, the adhesive layer 1 is directly formed. Thereby, the optical film 10A (with the release sheet attached) with the said adhesive layer was obtained.

2. An example where the optical film is a composite polarizing plate

An example of the adhesive layer-attached optical film of 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 a composite polarizing plate 2B and an adhesive layered on one side of the composite polarizing plate 2B (the lower surface in FIG. 2) Layer 1. In addition, although not shown, a release sheet may be laminated on the surface of the adhesive layer 1 opposite to the side of the composite polarizing plate 2B until the optical film 10B with the adhesive layer is used.

The adhesive layer 1 is formed of the adhesive of the foregoing embodiment.

The composite polarizing plate 2B in this embodiment is configured to include: a first retardation plate 24 in contact with the adhesive layer 1; and a second phase located on the side opposite to the adhesive layer 1 of the first retardation plate 24 Difference plate 25; the second adhesive layer 26 sandwiched between the first retardation plate 24 and the second retardation plate 25; laminated on the second retardation plate 25 opposite to the second adhesive layer 26 side The polarizer 21 on the side; and the protective layer 27 laminated on the side of the polarizer 21 opposite to the second retardation plate 25 side. In addition, although not shown, an 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. The composite polarizing plate 2B can well exhibit the viewing angle compensation performance.

(1) The first phase difference plate

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

Furthermore, it is preferable that the first retardation plate 24 is provided with an in-plane retardation by extension. As a result, the viewing angle compensation performance is more excellent.

The styrene resin constituting the phase difference expression layer 242 may be a homopolymer of styrene or its derivatives, or a binary or more copolymer of styrene or its derivatives and other copolymerizable monomers. . Styrene derivatives refer to compounds in which other groups are bonded to styrene, for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4- Alkyl styrenes such as dimethyl styrene, o-ethyl styrene, and p-ethyl styrene, or hydroxystyrene, tertiary butoxy styrene, vinyl benzoic acid, o-chlorostyrene, The benzene nucleus of styrene such as p-chlorostyrene is substituted with hydroxyl, alkoxy, carboxyl, halogen and the like.

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

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

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

The thickness of the retardation expression layer 242 is preferably 10-100 μm. By setting the thickness of the retardation expression layer 242 to 10 μm or more, a sufficient retardation value can be expressed by stretching. On the other hand, the thickness of the retardation expression layer 242 is 100 μm In the following cases, the impact strength is high, and the retardation change due to external stress is small. When applied to a liquid crystal display device, it is difficult to generate thermal unevenness.

The first acrylic resin layer 241 and the second acrylic resin layer 243 are preferably composed of a (meth)acrylic resin composition in which rubber particles are blended in a (meth)acrylic resin. By mixing 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, copolymers of alkyl methacrylates and alkyl acrylates, and the like. As alkyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc. are mentioned. Moreover, as alkyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, etc. are mentioned. Such (meth)acrylic resins can be those commercially available as general-purpose (meth)acrylic resins. In addition, (meth)acrylic resins also include those called impact-resistant (meth)acrylic resins, or those that have a glutaric anhydride structure or a lactone ring structure in the main chain are called high heat resistance (methyl) ) Acrylic resin.

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

The rubber particles may be formed by making a material with rubber elasticity into homogeneous particles, or may be a multilayer structure having at least one rubber elastic layer. Examples of acrylic rubber particles with a multilayer structure include: using the above-mentioned particles with rubber elasticity as the core and surrounding them with hard methacrylate Those covered with a base ester polymer; those with a hard alkyl methacrylate polymer as the core, and the surroundings are covered with an acrylic polymer with rubber elasticity as described above; and the surroundings of the hard core are covered with Covered with an acrylic polymer with rubber elasticity, and further covered with a hard alkyl methacrylate polymer, etc.

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

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~ per 100 parts by mass of the (meth)acrylic resin. About 50 parts by mass is preferable.

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

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

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

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

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

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

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

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

(2) Second phase difference plate

The second phase difference plate 25 is preferably made of olefin resin. Olefin-based resins refer to structural units derived from alicyclic olefins such as chain aliphatic olefins such as ethylene and propylene, or norbornene or its substitutes (hereinafter, these are also collectively referred to as norbornene-based monomers). The formed resin. The olefin resin may be a copolymer using two or more monomers.

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

The cyclic olefin resin may or may not have a norbornane ring in its structural unit. Examples of norbornene-based monomers that form cyclic olefin-based resins having no norbornene ring in the structural unit include those that become 5-membered rings by ring opening, and representative ones include norbornene and bicyclic Pentadiene, 1- or 4-methylnorbornene, 4-phenylnorbornene, etc. When the cyclic olefin resin is a copolymer, the arrangement of its molecules is not particularly limited. It can be a random copolymer or a block copolymer. It can also be a graft copolymer.

As more specific examples of cyclic olefin resins, for example, ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers, and the like Polymer modified products obtained by acid addition or cyclopentadiene addition, and polymers or copolymers obtained by hydrogenation of the same, addition polymers of norbornene-based monomers, norbornene-based monomers Addition copolymers with 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 resin, a resin obtained by hydrogenating a ring-opening polymer using a norbornene-based monomer can be preferably used. Such cyclic olefin resins can not only be stretched to form a phase difference plate, but also stretched and a shrinkable film with a predetermined shrinkage rate can be laminated and heat-shrinked, which is highly uniform and has A retardation plate with a large retardation value.

Commercial products of cyclic olefin resins using norbornene-based monomers (all under the trade name) include "ZEONEX" and "ZEONOR" sold by Zeon Corporation, and "ARTON" sold by JSR CORPORATION. Wait. These cyclic olefin resin films or their stretched films can be obtained from commercially available products, for example (all under the trade name), "ZEONOR film" sold by Zeon Corporation, and "ARTON film" sold by JSR CORPORATION , "ESSINA" sold by SEKISUI CHEMICAL CO., LTD., etc.

In addition, the second phase difference plate 25 can also be used, since it contains two types of A film composed of a mixed resin of an olefin resin, or a film composed of a mixed resin of an olefin resin and other thermoplastic resins. For example, as a mixed resin containing two or more kinds of olefin resins, a mixture of cyclic olefin resins and chain aliphatic olefin resins as described above can be mentioned. When a mixed resin of an olefin resin and another thermoplastic resin is used, the other thermoplastic resin 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 resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polyterephthalene Butylene formate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polyether ketone resin, polyether ether ketone resin, polyarylate resin, liquid crystal Resin, polyimide-based resin, polyimide-based resin, polytetrafluoroethylene-based resin, etc. The thermoplastic resin may be used alone or in combination of two or more. In addition, the above-mentioned thermoplastic resin may be used after any appropriate polymer modification. Examples of polymer modification include copolymerization, cross-linking, modification of molecular ends, and stereoregularity.

When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin relative to all resins is usually about 50% by mass or less, preferably about 40% by mass or less. By setting the content of other thermoplastic resins within this range, it is possible to obtain a retardation plate that has a small absolute value of the photoelastic coefficient, shows good wavelength dispersion characteristics, and is excellent in durability, mechanical strength, and transparency.

Olefin resins can be cast by solution or melt extrusion, etc. Make a film. When two or more mixed resins are used for film formation, the film formation method is not particularly limited. For example, it can be used: a uniform solution obtained by stirring and mixing the resin components with a solvent in a predetermined ratio and casting a film The method; the method of melt-mixing resin components in a predetermined ratio and manufacturing a film by the melt extrusion method, etc.

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

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

It is preferable that the second retardation plate 25 has refractive index anisotropy that satisfies the following condition, when the refractive index in the slow axis direction in the plane, the fast axis direction in the plane, and the thickness direction are 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 590nm in-plane retardation value R _e is 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 plate 25 having the refractive index anisotropy as described above can be formed by uniaxial stretching in the longitudinal direction of the film made of the above-mentioned olefin resin, uniaxial stretching in the transverse direction of the tenter, simultaneous biaxial stretching, or successive biaxial stretching. It can be obtained by stretching, etc., and can be appropriately adjusted by the stretching ratio and stretching speed, or by appropriately selecting the stretching At the time of preheating temperature, stretching temperature, thermosetting temperature, cooling temperature and other various temperatures and modes, 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 well-known adhesive can be used, which can be a curable adhesive or a non-curable adhesive, but from the viewpoint of suppressing dimensional changes due to thermal shrinkage of the polarizing plate From a standpoint, it is better to use an active energy ray-curable adhesive.

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

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

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

Examples of alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, ( N-butyl meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth) N-decyl acrylate, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, etc. . Among them, from the viewpoint of further improving adhesiveness, (meth)acrylate having an alkyl group with carbon number of 1 to 8 is preferred, and n-butyl (meth)acrylate is particularly preferred. In addition, these can be used alone or in combination of two or more kinds.

In the (meth)acrylate polymer (X), as a monomer unit constituting the polymer, 50 to 99% by mass of the alkyl group has a carbon number of 1 to 20 The alkyl (meth)acrylate is preferably contained, particularly preferably 60 to 99% by mass, and more preferably 70 to 98% by mass.

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

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

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

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

In the (meth)acrylate polymer (X), as the monomer unit constituting the polymer, 1 to 25% by mass of a reactive functional group-containing monomer is preferably contained, particularly preferably 1 to 20% by mass It is more preferable to contain 2 to 5% by mass.

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

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

Moreover, (meth)acrylate polymer (X) may be used individually by 1 type, and may be used in combination of 2 or more types.

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

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

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

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

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

The above-mentioned active energy ray-curable adhesives can also contain various additives as needed, such as: photopolymerization initiator, silane coupling agent, refractive index modifier, antistatic agent, thickener, antioxidant, ultraviolet absorber, light stabilizer Agent, softener, filler, etc.

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

As the photopolymerization initiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1 -Ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4-(2-hydroxyethyl) (Oxy) phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorodi Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethyl ketal Amino benzoate, oligomer [2-hydroxy-2-methyl-1 [4-(1-methylvinyl) phenyl] acetone], 2,4,6-trimethylbenzyl Group-diphenyl-phosphine oxide and so on. These can be used alone or in combination of two or more.

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

In addition, from improving the adhesion of the resulting adhesive to the film From a viewpoint, it is preferable that the said active energy ray-curable adhesive contains a silane coupling agent. As the silane coupling agent, it is preferably an organosilicon compound having at least one alkoxysilyl group in the molecule, which has good compatibility with the adhesive component and has light transmittance.

As the silane coupling agent, for example, in addition to the aforementioned epoxy group-containing silane coupling agent (D1) and mercapto group-containing silane coupling agent (D2), a polymerizable unsaturated group-containing silicon compound (for example, vinyl trimethoxy Silane, vinyl triethoxy silane, methacryloxy propyl trimethoxy silane, etc.), amino-containing silicon compounds (e.g. 3-aminopropyl trimethoxy silane, N-(2-amine Ethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc.), 3-chloropropyltrimethoxysilane Triethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, and an alkyl-containing silicon compound (e.g., methyltriethoxysilane, ethyltriethoxysilane, methyltrimethyl Condensates of oxysilane, ethyl trimethoxysilane, etc.). These can be used alone or in combination of two or more.

The content of the silane coupling agent 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, and more preferably 0.1 to 1 parts by mass .

In addition, the above-mentioned active energy ray-curable polymer system has a (meth)acrylate (co)polymer having an active energy ray-curable functional group (active energy ray-curable group) introduced into the side chain. good.

The thickness of the second adhesive layer 26 is usually about 1 to 50 μm, preferably 1 to 20 μm, and particularly preferably 2 to 7 μm. If the adhesive layer is too thin, the adhesiveness will decrease, and if it is too thick, it will easily cause problems such as the adhesive being squeezed out.

(4) Polarizer

As the polarizer 21, the same as the polarizer 21 of the aforementioned polarizing plate 2A 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 that may be sandwiched between the polarizer 21 and the protective layer 27 and/or between the polarizer 21 and the second retardation plate 25 may be the same as the adhesive layer of the aforementioned polarizer 2A.

(7) Manufacturing method of composite polarizing plate

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

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

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

After the adhesive layer is formed as described above, the protective layer 27 is bonded to one side of the polarizer 21 via the adhesive layer, and the second retardation plate 25 is bonded to the other side of the polarizer 21 to obtain protection Layer 27, polarizer 21 And a layered body (polarizing plate) constituted by the second retardation plate 25.

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

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

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

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

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

(8) Manufacturing method of optical film with adhesive layer

As an example of the method of manufacturing the adhesive layer-attached optical film 10B, an adhesive sheet made of a two-area peeling sheet on the adhesive layer is prepared as the aforementioned book In the adhesive sheet of the embodiment, the release sheet on one side (light release type release sheet) is peeled off. Then, the first phase difference plate 24 of the composite polarizing plate 2B is stacked 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) was obtained.

As another example of the manufacturing method of the adhesive layer-attached optical film 10B, the coating solution of the adhesive composition P is applied to the release surface of the release sheet, and after heat treatment is performed to form a coating film, the composite polarizing plate 2B The first retardation plate 24 is superimposed on the coating film. When the above-mentioned coating film requires an aging period, the aging period is separated to form the adhesive layer 1, and when the aging period is not required, the adhesive layer 1 is directly formed. Thereby, the above-mentioned optical film 10B with an adhesive layer (with a release sheet) was obtained.

3. Physical properties of optical film with adhesive layer

The surface resistivity of the adhesive layer of the adhesive layer-attached optical films 10A and 10B of this embodiment is preferably 1.0×10 ¹² Ω/sq or less, particularly preferably 5.0×10 ¹¹ Ω/sq or less, and further 6.0×10 ¹⁰ Ω/sq or less. By making the surface resistivity below the above value, sufficient antistatic properties can be exhibited in the display panel. This surface resistivity can be achieved by making the adhesive composition P contain an antistatic agent (C). In addition, the measurement of the surface resistivity of the adhesive layer was performed in accordance with JIS K6911, and the details are as shown in the test example described later. In addition, the lower limit of the above-mentioned surface resistivity is not particularly limited, but it is about 5.0×10 ⁸ Ω/sq from the viewpoint of not adversely affecting durability and heat-resistant unevenness.

The adhesive force of the optical films 10A and 10B with the adhesive layer of this embodiment relative to the adhesive force of the alkali-free glass is preferably 0.5-20N/25mm, particularly preferably 1-10N/25mm. With this, the optical film with the adhesive layer becomes Those with excellent durability. Furthermore, from the viewpoint of having excellent reworkability, the adhesive force is preferably 2 to 7 N/25 mm. In addition, the adhesive force mentioned here refers to the adhesive force measured by the 180° peeling method basically in accordance with JIS Z0237:2009, and is set as follows: Set the measurement sample to be 25 mm wide and 100 mm long, and place the measurement sample on After applying pressure at 0.5 MPa and 50°C for 20 minutes and sticking to the substrate, leaving it for 24 hours under the conditions of normal pressure, 23°C and 50% RH, and then measuring at a peeling speed of 300 mm/min. By keeping the adhesive force within the above range, it is possible to prevent floating or surface peeling when the liquid crystal cell is attached.

In addition, the adhesive layer-attached optical films 10A and 10B of this embodiment have been attached to the above-mentioned substrate and then left for 14 days under the conditions of 23°C and 50%RH. Adhesive force after days) is preferably 1~20N/25mm, particularly preferably 3~9N/25mm. By suppressing the increase of the adhesive force with the passage of time in this way, the optical films 10A and 10B with the adhesive layer of the present embodiment are also excellent in reworkability, and can be easily reattached after being attached to the liquid crystal cell.

4. Use of optical film with adhesive layer

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

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

The adhesive layer 1 of the adhesive layer-attached optical films 10A and 10B of the present embodiment exhibits good antistatic properties, and therefore can suppress the generation of static electricity when the release sheet is peeled off. Therefore, when the optical films 10A and 10B with the adhesive layer are attached to the liquid crystal cell as described above, the alignment of the liquid crystal molecules of the liquid crystal cell will not be disordered. In addition, dust or dust caused by static electricity can be prevented from entering the liquid crystal display. Inside the device.

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

In addition, the adhesive layer 1 of the optical film 10A, 10B with adhesive layer of this embodiment is also excellent in stress relaxation, and the resulting liquid crystal display device is not easy to warp under high temperature conditions, and thus hardly generates heat. Uneven. For example, if the glass plate with the optical film 10A and 10B attached with the adhesive layer is placed under high temperature conditions (for example, 80~85℃) for 250 hours, it is not easy to warp, and it is difficult to produce Uneven heat. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a thin film, the liquid crystal display device is not easily warped, and even if the liquid crystal cell is a high-definition liquid crystal cell, thermal unevenness is not easily generated.

Here, there may be a transparent conductive film on the bonding surface of the liquid crystal cell with the adhesive layer 1. In this case, corrosion or corrosion of the transparent conductive film can also be suppressed. The resistance value of the transparent conductive film changes. In particular, in this embodiment, by using a (meth)acrylate copolymer (A) having an acid value of 5 mgKOH/g or less, and using a specific antistatic agent (C), the above-mentioned effects can be fully exhibited.

Examples of the above-mentioned transparent conductive film include metals such as platinum, gold, silver, copper, and aluminum, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc dioxide, and tin-doped indium oxide (ITO) , Zinc oxide doped indium oxide, fluorine doped indium oxide, antimony doped tin oxide, fluorine doped tin oxide, aluminum doped zinc oxide and other composite oxides, chalcogenides, lanthanum hexaboride, titanium nitride, carbide Those composed of non-oxidizing compounds such as titanium.

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

[Example]

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

[Example 1]

1. Manufacturing of the first optical film (polarizing plate)

(1) Production of polarizer

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

(2) Production of polarizing plate

Preparation: 3 parts by mass of carboxyl 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 were added to the aqueous solution A resin, that is, an epoxy-based adhesive obtained by a polyamide epoxy-based additive (manufactured by Taoka Chemical Co., Ltd., trade name "Sumirez Resin 650(30)", an aqueous solution with a solid content of 30% by mass). This epoxy-based adhesive was applied to one surface of the polarizer obtained as described above.

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

Next, an epoxy-based adhesive was applied to the other side of the above-mentioned polarizer, and a zero retardation film made of a cyclic olefin resin with a thickness of 23 μm (produced by Zeon Corporation, Japan, trade name "ZEONOR") was bonded to the coating layer. ) As the second protective layer. After that, it was dried at 80°C for 5 minutes, thereby adhering the first protective layer and the second protective layer to the polarizer. After that, it was cured at 40°C for 168 hours to obtain a stack of the first protective layer (layer thickness 25μm), polarizer (elongation ratio 5 times, layer thickness 15μm) and second protective layer (layer thickness 23μm). Polarizing plate (first optical film) with a thickness of 63 μm.

2. Manufacturing of the second optical film (composite polarizer)

(1) 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid are copolymerized to prepare a (meth)acrylate polymer (X). The molecular weight of the (meth)acrylate polymer (X) was measured by the method described below, and as a result, the weight average molecular weight (Mw) was 2 million.

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

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

(2) Fabrication of the first phase difference plate

A methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "Technolloy S001") with approximately 20% by mass of acrylic rubber particles having an average particle diameter of 200 nm constituting the first acrylic resin layer was blended to form a phase difference Approximately 20 masses of styrene-maleic anhydride copolymer resin (NOVA Chemicals Corporation., trade name "DYLARK D332") of the expression layer and acrylic rubber particles with an average particle diameter of 200 nm that constitute the second acrylic resin layer % Methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "Technolloy S001"), co-extruded in this order for three layers to obtain a three-layer structure laminated film. The obtained laminated film was stretched to obtain a first phase difference plate (first acrylic resin layer/phase difference expression layer/second acrylic resin layer) having an in-plane retardation value of 60 nm and a thickness of 25 μm.

(3) Production of composite polarizing plate

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

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

<Ultraviolet radiation conditions>

‧Use high pressure mercury lamp

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

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

3. Manufacture of optical film with adhesive layer

(1) Preparation of (meth)acrylate copolymer

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

(2) Preparation of adhesive composition

100 parts by mass of the (meth)acrylate copolymer (A) obtained in the above-mentioned process (1) and trimethylolpropane-modified xylylene diisocyanate (Mitsui Chemicals) as the isocyanate-based crosslinking agent (B) , Manufactured by Incorporated, trade name "TAKENATE D110N") 0.2 parts by mass, as antistatic agent (C) N-decylpyridine bis(fluorosulfonyl) imine (solid ionic compound at room temperature) 1.5 Parts by mass, as epoxy-containing silane coupling agent (D1), 3-glycidyl ether propyl trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403") 0.2 parts by mass, as Cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane containing mercaptosilane coupling agent (D2) (Manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", mercapto equivalent: 450g/mole) 0.2 parts by mass, fully stirred, and diluted with ethyl acetate, thereby obtaining an adhesive composition物的coating solution.

Among them, each compounding (solid content conversion value) of the adhesive composition when the (meth)acrylate copolymer (A) is set to 100 parts by mass (solid content conversion value) is shown in Table 1. In addition, details such as abbreviations described in Table 1 are as follows.

[(Meth)acrylate copolymer]

BA: n-butyl acrylate

HEA: 2-hydroxyethyl acrylate

IBXA: Acrylic isoborneol

PhEA: 2-phenylethyl acrylate

CHA: Cyclohexyl acrylate

[Isocyanate-based crosslinking agent]

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

HDI: Trimethylolpropane modified hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATE HL")

[Antistatic Agent]

Pry+FSI-: N-decylpyridine bis(fluorosulfonyl)imine (ionic compound that is solid at room temperature)

K+PF6-: Potassium hexafluorophosphate (a solid ionic compound at room temperature)

(3) Production of optical film with adhesive layer

Silicone-based release agent on one side of the polyethylene terephthalate film After removing the peeling treatment surface of the peeling sheet (manufactured by LINTEC Corporation, SP-PET3811, thickness: 38μm), the coating solution of the adhesive composition obtained was coated with a knife coater, and then heated at 90°C 1 minute to form a coating film of the adhesive composition.

Next, the polarizing plate as the first optical film obtained in the above was bonded to the coating film so that the surface of the second protective layer was in contact with the exposed surface of the coating film, and the temperature was 23°C, 50%RH After aging for 7 days, the first adhesive layer-attached optical film with the adhesive layer formed on the polarizing plate was obtained. In addition, the thickness of the formed adhesive layer was 20 μm.

And, the composite polarizing plate as the second optical film obtained in the above was pasted 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 Then, they were cured at 23°C and 50% RH for 7 days to obtain a second adhesive layer-attached optical film with an adhesive layer formed on the composite polarizing plate. In addition, the thickness of the formed adhesive layer was 20 μm.

[Examples 2~12, Comparative Examples 1~7]

The types and proportions of the monomers constituting the (meth)acrylate copolymer (A), the weight average molecular weight of the (meth)acrylate copolymer (A), and the type and blending of the isocyanate-based crosslinking agent (B) The amount, and the type and compounding amount of the antistatic agent (C) were changed as shown in Table 1, and the optical film with an adhesive layer was produced in the same manner as in Example 1.

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

<Measurement conditions>

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

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

TSK guard column HXL-H

TSK gel GMHXL(×2)

TSK gel G2000HXL

‧Measuring solvent: Tetrahydrofuran

‧Measuring temperature: 40℃

The following test examples are performed on the second adhesive layer-attached optical film manufactured in the examples and comparative examples.

[Test Example 1] (Measurement of Gel Fraction)

Instead of the optical film used in the production of the adhesive layer-attached optical film in the examples or comparative examples, a peeling sheet in which the polyethylene terephthalate film is peeled off with a silicone-based release agent (LINTEC Corporation Manufacture, SP-PET3801, thickness: 38μm) to make adhesive sheets. Specifically, on the exposed coating film of the constituent body composed of the release sheet obtained in the manufacturing process of the embodiment or the comparative example and the coating film of the adhesive composition, the above-mentioned release sheet is in contact with the release treatment surface side Laminated in the same way and cured for seven days at 23°C and 50%RH. Thereby, an adhesive sheet composed of a structure of release sheet (SP-PET3801)/adhesive layer (thickness: 20 μm)/release sheet (SP-PET3811) was produced.

The obtained adhesive sheet was cut into a size of 80mm×80mm, and the adhesive layer was covered with a polyester mesh (mesh size 200), and the mass was weighed with a precision balance. Remove the individual mass of the above mesh fabric 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 and dried in an air-dried environment at a temperature of 23°C and a relative humidity of 50% for 24 hours, 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. Gel fraction (%) is represented by (M2/M1)×100. The results are shown in Table 2.

[Test Example 2] (Evaluation of Durability)

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

After that, it was put into the environment under the following three endurance conditions, and after 250 hours, it was confirmed whether there was floating or surface peeling with a 10x magnifying glass. The evaluation criteria are as follows. The results are shown in Table 2.

◎: Floating or surface peeling is not confirmed.

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

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

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

<Endurance Conditions>

‧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 films with adhesive layers obtained in the examples and comparative examples were cut to a length of 200 mm and a width of 150 mm. Peel off the release sheet from the adhesive layer-attached optical film, and bond the exposed adhesive layer to an alkali-free glass with a length of 250 mm, a width of 175 mm, and a thickness of 0.5 mm (manufactured by Corning Incorporated, trade name "Eagle-XG" ), use this as a sample. The sample was placed at 85°C in a dry atmosphere for 250 hours. After that, it was taken out under an environment of 25°C and 50% RH, and the polarizing plate was placed on a horizontal platform with the side of the polarizing plate facing up, and the amount of warpage between each corner (4 points) of the sample and the stage was measured (the distance between the corner and the stage) ) To add up the warpage of each corner. Based on the results, the warpage resistance was evaluated as follows. The results are shown in Table 2.

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

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

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

×: The total amount of warpage exceeds 20 mm

[Test Example 4] (Evaluation of Heat Inhomogeneity)

The optical films with adhesive layers obtained in the examples and comparative examples were adjusted to a size of 200 mm×150 mm with a cutting device (Super Cutter PN1-600 manufactured by Ogino Seisakusho Co., Ltd.). After peeling off the release sheet and affixed to alkali-free glass (manufactured by Corning Incorporated, Eagle XG) via the exposed adhesive layer, it was pressurized at 0.5 MPa and 50°C for 20 minutes in an autoclave manufactured by KURIHARA. In addition, the above-mentioned bonding is performed on the front and back surfaces of the alkali-free glass so that the polarization axis of the optical film with the adhesive layer is in the orthogonal polarization state (polarization axis: ∠45°, ∠135°). In this state, dry at 80°C After leaving for 250 hours in a (dry) environment, leaving it for 2 hours in an environment of 23°C and 50% RH, 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 (FLAT ILLUMINATOR) (manufactured by Raytronics Corp., HF-SL-A312LC, illuminance: 26,000 Lux, brightness: 10,000 cd), and a two-dimensional color luminance meter (KONICA MINOLTA, INC. made, CA-2000) to shoot, and use analysis software (KONICA MINOLTA, INC. make, CA-S20w) to convert into a brightness distribution image. The brightness distribution image of the obtained sample was evaluated based on the evaluation criteria shown in FIG. 4 and the following.

◎: The brightness distribution is approximately uniform.

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

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

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

[Test Example 5] (Evaluation of corrosion resistance)

<Production of metal film laminated glass substrate>

By a sputtering method using aluminum as a sputtering target and argon as a sputtering gas, a metal aluminum layer with a thickness of 500 nm was formed on one surface of an alkali-free glass prepared in advance.

Next, a methacrylic acid derivative containing a phosphoric acid group (manufactured by KYOEISHA CHEMICAL Co., Ltd.) was mixed with an acrylic hard coat agent (manufactured by JSR CORPORATION, Opstar (registered trademark) Z7535) so that the solid content was 2% by mass. , Light ester P-2M), as a dilution The solvent was diluted with methyl ethyl ketone to a solid content concentration of 7.5% by mass, thereby obtaining a hard coat agent coating liquid.

The obtained hard coat agent coating solution was applied to the exposed surface side of the metal aluminum layer, dried at 80°C for 3 minutes, and then irradiated with ultraviolet rays (using a mercury lamp, 1200mJ/cm ² ) to crosslink the coating film. This formed a surface hard coat with a thickness of 2.0 μm. Thereby, a metal film laminated glass substrate in which a metal aluminum layer and a surface hard coat layer were sequentially formed on one surface of the glass substrate was produced.

<Evaluation of corrosion resistance>

The optical films with adhesive layers obtained in the examples and comparative examples were cut into test pieces with a size of 20 mm×50 mm. The release sheet was peeled from the test piece, and the exposed adhesive layer was attached to the exposed surface side of the hard coat layer on the surface of the metal film laminated glass substrate obtained in the above process. After storing this in an oven at a temperature of 60°C and a relative humidity of 90% for 750 hours, it was taken out at room temperature. In addition, the state of the metal aluminum layer in the portion of the metal film laminated glass substrate where the test piece was bonded was observed, and the corrosion resistance was evaluated based on the following criteria. The results are shown in Table 2.

○: No pitting corrosion or white turbidity occurred in the metal aluminum layer.

×: Pitting corrosion and white turbidity occurred in the metal aluminum layer.

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

The optical films with adhesive layers obtained in the examples and comparative examples were cut into a size of 50 mm×50 mm, and the obtained samples were left at a temperature of 23° C. and a humidity of 50% RH for 24 hours. After that, the peeling sheet was peeled off, and the surface resistivity (Ω) was measured on the surface of the exposed adhesive layer using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Hiresta UP MCP-HT450) and in accordance with JIS K6911 /sq). The results are shown in Table 2.

[Test Example 7] (Measurement of Adhesion-Evaluation of Reworkability)

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

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

Based on the adhesive force 14 days after the attachment, the reworkability was evaluated based on the following criteria. The results are shown in Table 2.

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

○: Adhesion after 14 days of attachment exceeds 8.8N/25mm and less than 10N/25mm

△: Adhesive force 14 days after sticking is 10N/25mm or more and less than 20N/25mm

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

[Test Example 8] (Measurement of Haze Value)

The adhesive layer corresponding to each example or each comparative example was produced in the same manner as in Test Example 1, and a release sheet (SP-PET3801)/adhesive layer (thickness: 20 μm) / Adhesive sheet composed of peeling sheet (SP-PET3811) (cured for 7 days). With respect to the adhesive layer of the adhesive sheet, the haze value (%) (in some cases abbreviated as Hz (%)) was measured using a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES Co., LTD, NDH2000) in accordance with JIS K7136:2000. The results are shown in Table 2.

It can be seen from Table 2 that the optical film with the adhesive layer obtained in the examples has excellent durability, and is not prone to warpage at high temperatures, nor is it prone to heat unevenness. In addition, the optical film with the adhesive layer obtained in the examples has excellent corrosion resistance to the transparent conductive film, and the surface resistivity of the adhesive layer is low, which shows good antistatic properties. Moreover, the optical film with the adhesive layer obtained in the examples is excellent in reworkability, and the transparency of the adhesive layer of the examples is also high.

[Industrial availability]

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

1‧‧‧Adhesive layer

2A‧‧‧Polarizer

10A‧‧‧Optical film with adhesive layer

21‧‧‧Polarizer

22‧‧‧The first protective layer

23‧‧‧Second protection layer

Claims (9)

An adhesive obtained from an adhesive composition containing: (meth)acrylate copolymer (A), as a monomer unit constituting the polymer, containing alicyclic structure-containing monomer (a1) , Aromatic ring-containing monomers (a2) and hydroxyl-containing monomers (a3), the hydroxyl value is 5-20mgKOH/g, the acid value is below 2mgKOH/g, and the weight average molecular weight is 1.3 million to 3 million; isocyanate-based crosslinking agent (B); and antistatic agent (C), the adhesive is characterized in that: the gel fraction of the adhesive is 62 to 90%, and the antistatic agent (C) is an anion containing fluorosulfonamide The ionic compound is attached to a transparent conductive film. The adhesive described in item 1 of the scope of patent application, wherein the alicyclic structure in the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure. The adhesive described in item 1 of the scope of patent application, wherein the adhesive composition further contains an epoxy-containing silane coupling agent (D1). The adhesive described in item 1 of the scope of patent application, wherein the adhesive composition further contains a mercapto-containing silane coupling agent (D2). The adhesive described in item 1 of the scope of patent application, wherein the isocyanate-based crosslinking agent (B) is a compound having an aromatic ring. The adhesive described in item 1 of the scope of patent application, wherein the antistatic agent (C) is an ion containing a nitrogen-containing heterocyclic cation as a cation Sexual compounds. An adhesive sheet, characterized by having an adhesive layer composed of the adhesive described in any one of items 1 to 6 of the scope of patent application. An optical film with an adhesive layer, characterized by comprising: an optical film; and an adhesive layer laminated on at least one side of the optical film as described in any one of items 1 to 6 of the scope of patent application Adhesive composition. A laminated body, characterized by comprising: an optical film; an adhesive layer composed of the adhesive as described in any one of claims 1 to 6 laminated on at least one side of the optical film; and transparent conductive The film is laminated on the side of the adhesive layer opposite to the optical film.

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