CN112180491A

CN112180491A - Polarizing film, method for producing same, optical film, and image display device

Info

Publication number: CN112180491A
Application number: CN202010624600.0A
Authority: CN
Inventors: 大学纪二
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2019-07-01
Filing date: 2020-07-01
Publication date: 2021-01-05
Also published as: KR20210003053A; TW202112545A; JP2021009231A

Abstract

The present invention addresses the problem of providing a polarizing film that is free from spot white spot defects and free from local expansion of the surface of a transparent protective film, a method for producing the polarizing film, an optical film, and an image display device. The polarizing film of the present invention is provided with a transparent protective film on at least one surface of a polarizer via an adhesive layer, wherein one surface of the transparent protective film is a surface having a convex portion, the adhesive layer is provided on the surface having the convex portion of the transparent protective film, and the thickness of the adhesive layer is 1.6 [ mu ] m or more.

Description

Polarizing film, method for producing same, optical film, and image display device

Technical Field

The present invention relates to a method for producing a polarizing film in which a transparent protective film is provided on at least one surface of a polarizer with an adhesive layer interposed therebetween. The polarizing film may be used alone or in combination with an optical film of the polarizing film to form an image display device such as a Liquid Crystal Display (LCD), an organic EL display, a CRT, or a PDP.

Background

In watches, mobile phones, PDAs, notebook computers, monitors for computers, DVD players, TVs, and the like, liquid crystal display devices are rapidly on the market. A liquid crystal display device is a device that visualizes the polarization state of a liquid crystal switch, and uses a polarizer in view of the display principle. In particular, in applications such as TVs, high brightness, high contrast, and wide viewing angles are increasingly required, and polarizing films are also increasingly required to have high transmittance, high polarization, high color reproducibility, and the like.

As the polarizer, for example, an iodine polarizer having a structure in which iodine is adsorbed to polyvinyl alcohol (hereinafter, also referred to as "PVA") and stretched is most widely used in view of high transmittance and high degree of polarization. In general, a polarizing film is used in which transparent protective films are laminated on both surfaces of a polarizer by a so-called aqueous adhesive prepared by dissolving a polyvinyl alcohol-based material in water (patent documents 1 and 2 listed below). As the transparent protective film, cellulose triacetate having high moisture permeability or the like is used. When the above aqueous adhesive is used (so-called wet lamination), a drying step is required after the polarizer and the transparent protective film are bonded.

On the other hand, an active energy ray-curable adhesive is proposed instead of the aqueous adhesive. When the polarizing film is produced using the active energy ray-curable adhesive, the productivity of the polarizing film can be improved because a drying step is not required. For example, the present inventors have proposed a radical polymerization type active energy ray-curable adhesive using an N-substituted amide monomer as a curable component (patent document 3 below).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2001-296427

Patent document 2: japanese patent laid-open No. 2007 and 256569

Patent document 3: japanese patent laid-open No. 2012 and 052000

Disclosure of Invention

Problems to be solved by the invention

However, in a conventional polarizing film in which a polarizer and a transparent protective film are bonded to each other with an adhesive layer, a spot-like white spot defect may occur, and local swelling may occur on the surface of the transparent protective film.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a polarizing film which has no white spot defect in a dot shape and has no local expansion of the surface of a transparent protective film.

Means for solving the problems

The above problem can be solved by the following constitution.

That is, the present invention relates to a polarizing film having a transparent protective film provided on at least one surface of a polarizer via an adhesive layer,

one surface of the transparent protective film is a surface having a convex portion,

the adhesive layer is provided on the surface of the transparent protective film having the convex portion,

the adhesive layer has a thickness of 1.6 [ mu ] m or more.

As an embodiment of the transparent protective film, a surface of the transparent protective film having a convex portion is a support peeling surface after peeling the film-forming support, and the convex portion is formed by a concave portion on a surface of the film-forming support.

Preferably, the transparent protective film is a cellulose resin film.

The thickness of the transparent protective film is preferably 30 μm or less.

Preferably, the polarizing film has an easy-adhesion layer on the surface to be bonded to the polarizer, and the easy-adhesion layer is a part of the adhesive layer.

The easy adhesion composition which is a material for forming the easy adhesion layer preferably contains a compound represented by the following general formula (1) and/or an organometallic compound having an M — O bond in the structural formula.

[ chemical formula 1]

In the formula (1), X is a functional group containing a reactive group, R¹And R²Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group or a heterocyclic group. In the present invention, the compound represented by the above general formula (1) is also referred to as "boron-containing compound".

The compound represented by the above general formula (1) is preferably a compound represented by the following general formula (1'),

[ chemical formula 2]

In the formula (1'), Y is an organic group, X, R¹And R²The same as above.

Preferably, the reactive group of the compound represented by the above general formula (1) is at least 1 reactive group selected from the group consisting of an α, β -unsaturated carbonyl group, a vinyl ether group, an epoxy group, an oxetanyl group, an amino group, an aldehyde group, a mercapto group and a halogen group.

Preferably, the easy-adhesion composition contains an SP value of 21.0 (MJ/m)³)^1/2Above and 26.0 (MJ/m)³)^1/2The following polymerizable compound X.

The present invention also relates to a method for producing a polarizing film having a transparent protective film provided on at least one surface of a polarizer with an adhesive layer interposed therebetween,

the method comprises the following steps:

a coating step of coating an adhesive composition on the surface of the transparent protective film having the convex portion;

a bonding step of bonding the polarizer and the transparent protective film; and

and an adhesive step of adhering the polarizer and the transparent protective film via the adhesive layer having a thickness of 1.6 μm or more, wherein the adhesive layer is obtained by curing the adhesive composition.

The adhesive composition preferably has a viscosity of 0.5 to 100 mPas when applied.

Preferably, the method for producing the polarizing film includes:

an application step of applying an easy adhesion composition containing a compound represented by the following general formula (1) and/or an organometallic compound having an M-O bond in the structural formula,

[ chemical formula 3]

In the formula (1), X is a functional group containing a reactive group, R¹And R²Each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group or a heterocyclic group,

m is silicon, titanium, aluminum or zirconium, and O is an oxygen atom.

In addition, the present invention relates to an optical film having the polarizing film.

The present invention also relates to an image display device having the polarizing film or the optical film.

ADVANTAGEOUS EFFECTS OF INVENTION

The present inventors have studied the cause of the occurrence of a spot-like white spot defect in a conventional polarizing film and the local expansion of the surface of a transparent protective film. The above problem is considered to be caused by the following reasons.

Conventionally, in the case of producing a polarizing film by laminating a polarizer and a transparent protective film with an adhesive layer, the surface of the transparent protective film to be provided with the adhesive layer is not particularly limited, and the adhesive layer is provided on any surface of the transparent protective film.

It is considered that in the process of producing the transparent protective film, for some reason, minute convex portions are formed on the surface of the transparent protective film, and if an adhesive layer is formed on the surface having the convex portions of the transparent protective film, it becomes difficult to form the adhesive layer on the convex portions, and therefore, white spot defects are generated due to the convex portions. Further, it is considered that when the bonding surface of the polarizer and the surface having the convex portion of the transparent protective film are bonded via the adhesive composition, the bonding surface of the polarizer comes into contact with the convex portion to apply pressure to the convex portion. As a result, the convex portion to which pressure is applied presses the transparent protective film around the convex portion outward to deform, and local expansion occurs on the surface of the transparent protective film.

The present inventors have found that even when an adhesive layer is provided on the surface of the transparent protective film having the convex portion, a polarizing film free from spot-like white spot defects and free from local swelling on the surface of the transparent protective film can be obtained by setting the thickness of the adhesive layer to 1.6 μm or more. It is considered that the adhesive layer having a thickness of 1.6 μm or more completely covers the convex portions on the surface of the transparent protective film, and therefore, the occurrence of white spot defects is suppressed. Further, it is considered that when the thickness of the adhesive layer is 1.6 μm or more, the pressure applied to the convex portion at the time of bonding is relaxed by the adhesive composition, and the transparent protective film around the convex portion is not easily pressed outward by the convex portion, and therefore, local expansion is not easily generated on the surface of the transparent protective film.

As one of the reasons for forming the convex portion on the surface of the transparent protective film, the following is considered.

A transparent protective film such as a cellulose triacetate film is generally produced by a so-called solution casting film-forming method as follows: the polymer is dissolved in a solvent, the resulting polymer solution is applied to a film-forming support to form a coating film, the solvent is volatilized from the formed coating film to form a film, and the formed film is then peeled off from the film-forming support.

In the process of producing the transparent protective film, it is considered that a convex portion is formed on a surface (support peeling surface) of the transparent protective film on the side from which the film-forming support is peeled off, due to a concave portion such as a minute flaw or a pinhole present on the surface of the film-forming support.

As a method for solving the problem of occurrence of a spot-like white spot defect and local swelling of the surface of the transparent protective film, a method of providing an adhesive layer on a surface (air side surface) of the transparent protective film other than the release surface of the support is considered. However, it is known that a specific curable component in the adhesive composition may easily penetrate into the film on the air side surface of the transparent protective film, and when the curable component penetrates into the film excessively, a brittle layer is formed in the adhesive layer, and thus the adhesive strength is lowered. Therefore, the method of providing the adhesive layer on the air side surface of the transparent protective film limits the design of the adhesive composition. When the adhesive layer is provided on the support release surface side of the transparent protective film, a polarizing film free from spot white spot defects and local swelling on the surface of the transparent protective film can be obtained by setting the thickness of the adhesive layer to 1.6 μm or more as described above.

The present inventors have also found that the problem of occurrence of a spot-like white spot defect and local swelling of the surface of the transparent protective film is likely to occur when a cellulose-based resin film is used. Therefore, the present invention is particularly effective when a cellulose-based resin film is used.

Further, the present inventors have found that the problem of local swelling of the surface of the transparent protective film is likely to occur when the thickness of the transparent protective film is 30 μm or less. Therefore, the present invention is effective particularly when a transparent protective film having a thickness of 30 μm or less is used.

Further, when the bonding surface of the polarizer and the surface having the convex portion of the transparent protective film are bonded to each other with the adhesive composition interposed therebetween, there is a problem that air bubbles are likely to be mixed between the bonding surface of the polarizer and the convex portion. The present inventors have found that by providing an easy-adhesion composition layer (an easy-adhesion layer which becomes a part of an adhesive layer after curing) in advance on the bonding surface of the polarizer, air bubbles are less likely to be mixed between the bonding surface of the polarizer and the convex portion.

The easy-adhesion composition as a material for forming the easy-adhesion layer preferably contains the boron-containing compound. The boron-containing compound may react with a functional group such as a hydroxyl group of the polarizer. This improves the adhesiveness between the polarizer and the adhesive layer, and as a result, the polarizing film exhibits an effect of improving the water-resistant adhesiveness. However, when the moisture content of the polarizer is low, for example, when the moisture content of the polarizer is 15 mass% or less, the boron-containing compound and the functional group of the polarizer cannot sufficiently react with each other, and therefore, the effect may not be sufficiently obtained. However, even when the water content of the polarizer is low, the reactivity of the boron-containing compound with respect to the functional group of the polarizer is improved by adding water to the easy-adhesion composition, and the adhesion between the polarizer and the adhesive layer can be improved. As a result, even when the water content of the polarizer is low, the improvement of the water-resistant adhesiveness of the polarizing film and the improvement of the applicability of the easy-adhesion composition can be achieved at the same time.

In addition, the easy adhesion composition preferably contains the organometallic compound. The organometallic compound becomes an active metal species due to inclusion of moisture, and as a result, the organometallic compound can form a strong bond with the polarizer. However, the above-mentioned organometallic compound has a plurality of reaction sites, and therefore, the organometallic compound which reacts with the polarizer also has an unreacted site. The organometallic compound can form a strong bond with a curable component in the adhesive composition applied to the bonding surface of the transparent protective film. As described above, the organic metal compound can form a strong bond with both the polarizer and the adhesive layer, and therefore the water-resistant adhesion between the polarizer and the adhesive layer is greatly improved.

Further, it is preferable that the easy-adhesion composition contains an SP value of 21.0 (MJ/m)³)^1/2Above and 26.0 (MJ/m)³)^1/2The following polymerizable compound X. The SP value of the polymerizable compound X is close to the SP value of a transparent protective film such as unsaponifiable cellulose triacetate film or acrylic film, and therefore, the polymerizable compound X contributes to improvement in adhesion between the adhesive layer and the transparent protective film. The polymerizable compound X is a raw material of the adhesive layer, and is therefore usually blended in the adhesive composition. As described above, the polymerizable compound X contributes to improvement in adhesion between the adhesive layer and the transparent protective film, and therefore, it is preferable to add a large amount of the compound X to the adhesive composition. However, if a large amount of the polymerizable compound X is blended in the adhesive composition, the polymerizable compound X easily penetrates into the transparent protective film. If the polymerizable compound X penetrates into the transparent protective film excessively, a brittle layer is formed in the adhesive layer, thereby reducing the adhesive strength. As a result, the adhesiveness between the adhesive layer and the transparent protective film is reduced. By blending the polymerizable compound X in the easy adhesion composition in advance, the easy adhesion layer and the adhesive layer can be integrated (the easy adhesion layer is a part of the adhesive layer) while preventing the excessive penetration of the polymerizable compound X into the transparent protective film, and the reaction between the polymerizable compound X in the easy adhesion composition and the curable component in the adhesive composition. Thus, the adhesion between the polarizer and the adhesive layer can be improved without reducing the adhesion between the adhesive layer and the transparent protective film.

In addition, when the adhesive composition is applied to the surface of the transparent protective film having the convex portion, there is a problem that air bubbles are easily mixed into the periphery of the convex portion. The present inventors have found that bubbles are less likely to be mixed into the periphery of the convex portion by adjusting the viscosity of the adhesive composition at the time of application to 0.5 to 100 mPas.

Detailed Description

The polarizing film of the present invention is provided with a transparent protective film on at least one surface of a polarizer via an adhesive layer, wherein one surface of the transparent protective film is a surface having a convex portion, the adhesive layer is provided on the surface having the convex portion of the transparent protective film, and the thickness of the adhesive layer is 1.6 [ mu ] m or more.

Hereinafter, the polarizing film of the present invention will be described in detail.

< polarizer >

In the present invention, from the viewpoint of improving optical durability in a severe environment under high temperature and high humidity, a thin polarizer having a thickness of 3 μm or more and 15 μm or less is preferably used as the polarizer, and more preferably 12 μm or less, further preferably 10 μm or less, and particularly preferably 8 μm or less. Such a thin polarizer has excellent durability against thermal shock because of its small thickness variation, excellent visibility, and small dimensional change.

In addition, the thin polarizer generally has a low water content, and more specifically, the water content is 15 mass% or less in many cases. Such a low-moisture-content thin polarizer has the above-described effects, but on the other hand, the reactivity with the boron-containing compound or the organic metal compound contained in the easy-adhesion composition used in the present invention is low, and the effect of improving the adhesion between the polarizer and the adhesive layer may be insufficient. Therefore, in the polarizing film of the present invention, when a polarizer having a water content of 15 mass% or less is used, the easy-adhesion composition preferably contains water, and specifically, the content of water is preferably 5 to 90 mass%, more preferably 30 to 80 mass% when the total amount of the easy-adhesion composition is 100 mass%.

As the polarizer, a polarizer using a polyvinyl alcohol resin can be used. Examples of polarizers include: a film obtained by adsorbing a dichroic substance such as iodine or a dichroic dye to a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film and uniaxially stretching the film, a polyene-based alignment film such as a dehydrated polyvinyl alcohol or a desalted polyvinyl chloride film, or the like. Among these, a polarizer formed of a dichroic material such as iodine and a polyvinyl alcohol film is preferable.

A polarizer obtained by uniaxially stretching a polyvinyl alcohol film dyed with iodine can be produced, for example, as follows: the polyvinyl alcohol is dyed by immersing in an aqueous iodine solution and stretched to 3 to 7 times the original length. The coating composition may be immersed in an aqueous solution of potassium iodide or the like optionally containing boric acid, zinc sulfate, zinc chloride or the like as necessary. If necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol film with water, not only stains and an anti-blocking agent on the surface of the polyvinyl alcohol film can be washed, but also unevenness such as uneven dyeing can be prevented by swelling the polyvinyl alcohol film. The stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed after dyeing with iodine. Stretching may be carried out in an aqueous solution such as boric acid or potassium iodide or in a water bath.

In view of tensile stability and humidification reliability, the polarizer preferably contains boric acid. In addition, from the viewpoint of suppressing the occurrence of through cracks, the content of boric acid contained in the polarizer is preferably 22 mass% or less, more preferably 20 mass% or less, with respect to the total amount of the polarizer. From the viewpoint of tensile stability and humidification reliability, the boric acid content is preferably 10 mass% or more, more preferably 12 mass% or more, with respect to the total amount of the polarizer.

Typical examples of the thin polarizers include thin polarizers described in japanese patent No. 4751486, japanese patent No. 4751481, japanese patent No. 4815544, japanese patent No. 5048120, international publication No. 2014/077599, and international publication No. 2014/077636, and thin polarizers obtained by the production methods described in these documents.

As the thin polarizer, among the production methods including the step of stretching in a state of a laminate and the step of dyeing, from the viewpoint of being capable of stretching to a high magnification to improve the polarizing performance, a thin polarizer obtained by a production method including the step of stretching in an aqueous boric acid solution as described in japanese patent No. 4751486, japanese patent No. 4751481, and japanese patent No. 4815544 is preferable, and a thin polarizer obtained by a production method including the step of stretching in an auxiliary gas atmosphere before stretching in an aqueous boric acid solution as described in japanese patent No. 4751481 and japanese patent No. 4815544 is particularly preferable. These thin polarizing films can be obtained by a production method including a step of stretching a polyvinyl alcohol resin (hereinafter, also referred to as PVA-based resin) layer and a stretching resin base material in a state of a laminate and a step of dyeing. With this production method, even if the PVA-based resin layer is thin, it can be stretched while being supported by the resin base material for stretching without causing troubles such as breakage due to stretching.

< transparent protective film >

The transparent protective film used in the present invention is not particularly limited, and for example, it can be produced by a so-called solution casting film-forming method as follows: the polymer is dissolved in a solvent, the resulting polymer solution is applied to a film-forming support to form a coating film, the solvent is volatilized from the formed coating film to form a film, and the formed film is then peeled off from the film-forming support. The transparent protective film may be produced by extrusion molding on a film-forming support.

One surface of the transparent protective film used in the present invention is a surface having a convex portion. In one aspect of the transparent protective film, a surface of the transparent protective film having a convex portion is a support peeling surface after peeling the film-forming support, and the convex portion is formed by a concave portion on a surface of the film-forming support. The shape of the projections is not particularly limited, and the projections are mainly (for example, 80% or more of the total projections) in a mountain shape. The height of the convex part varies depending on the kind of the transparent protective film, but is usually about 6 μm at the maximum, for example, 0.5 to 3 μm, 1 to 2.5 μm, or 1.2 to 2 μm on average. The size (maximum width) of the convex portion is usually about 50 μm at the maximum, for example, 5 to 30 μm, 10 to 20 μm, or 10 to 15 μm on average, depending on the kind of the transparent protective film.

The transparent protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like. Examples thereof include: polyester polymers such AS polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such AS cellulose diacetate and cellulose triacetate, acrylic polymers such AS polymethyl methacrylate, styrene polymers such AS polystyrene and acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. Further, polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, polyolefin polymer such as ethylene-propylene copolymer, vinyl chloride polymer, polyamide polymer such as nylon and aromatic polyamide, imide polymer, sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, polyaryl ester polymer, polyacetal polymer, epoxy polymer, or a mixture of the above polymers may be cited as examples of the polymer forming the transparent protective film. The transparent protective film may contain 1 or more kinds of any appropriate additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100 mass%, more preferably 50 to 99 mass%, even more preferably 60 to 98 mass%, and particularly preferably 70 to 97 mass%. When the content of the thermoplastic resin in the transparent protective film is 50% by mass or less, there is a fear that high transparency and the like originally possessed by the thermoplastic resin cannot be sufficiently expressed.

Further, as the transparent protective film, there can be mentioned a polymer film described in Japanese patent laid-open No. 2001-343529 (WO01/37007), for example, a resin composition containing (A) a thermoplastic resin having a substituted and/or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted and/or unsubstituted phenyl group and a nitrile group in a side chain. Specifically, a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer is exemplified. As the film, a film formed from a mixed extrusion of a resin composition or the like can be used. These films have a small phase difference and a small photoelastic coefficient, and therefore can eliminate problems such as unevenness due to strain of the polarizing film, and have a small moisture permeability, and therefore have excellent humidification durability.

Further, the transparent protective film used in the present invention has a moisture permeability of 150g/m²The time is less than 24 h. According to this configuration, moisture in the air is less likely to enter the polarizing film, and a change in the moisture percentage of the polarizing film itself can be suppressed. As a result, curling and dimensional change of the polarizing film due to the storage environment can be suppressed.

The transparent protective film provided on one or both surfaces of the polarizer is preferably a transparent protective film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like, and particularly, the moisture permeability is more preferably 150g/m²Less than 24h, particularly preferably 120g/m²A time of 24 hours or less, preferably 5 to 70g/m²The time is less than 24 h.

As a material for forming the transparent protective film satisfying the low moisture permeability, for example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate; a polycarbonate resin; a polyarylate resin; amide resins such as nylon and aromatic polyamide; polyolefin polymers such as polyethylene, polypropylene and ethylene-propylene copolymers, cyclic olefin resins having a cyclic or norbornene structure, (meth) acrylic resins, or mixtures thereof. Among the above resins, polycarbonate-based resins, cyclic polyolefin-based resins, and (meth) acrylic resins are preferable, and cyclic polyolefin-based resins and (meth) acrylic resins are particularly preferable.

In the present invention, a cellulose resin film is preferably used as the transparent protective film, and a cellulose triacetate film is more preferably used.

The thickness of the transparent protective film may be suitably determined, and is generally preferably 5 to 100 μm, more preferably 10 to 50 μm, further preferably 10 to 30 μm, and particularly preferably 10 to 25 μm in view of strength, handling properties such as handling properties, thin layer properties, and the like.

The transparent protective film generally has a front retardation of less than 40nm and a thickness direction retardation of less than 80 nm. The front phase difference Re is represented by Re ═ nx-ny) × d. The thickness direction retardation Rth is represented by Rth ═ x-nz) × d. The Nz coefficient is represented by Nz ═ (nx-Nz)/(nx-ny). [ wherein, the refractive indexes in the slow axis direction, the fast axis direction and the thickness direction of the film are nx, ny and nz, respectively, and d (nm) is the thickness of the film. The slow axis direction is a direction in which the refractive index in the film plane becomes maximum. ]. The transparent protective film is preferably free from coloring as much as possible. It is preferable to use a protective film having a retardation value in the thickness direction of-90 nm to +75 nm. By using the protective film having a retardation value (Rth) in the thickness direction of-90 nm to +75nm, the coloring (optical coloring) of the polarizing film caused by the transparent protective film can be substantially eliminated. The retardation value (Rth) in the thickness direction is more preferably from-80 nm to +60nm, particularly preferably from-70 nm to +45 nm.

On the other hand, as the transparent protective film, a retardation plate having a retardation of 40nm or more in a front direction and/or 80nm or more in a thickness direction can be used. The front retardation is usually controlled to be in the range of 40 to 200nm, and the thickness direction retardation is usually controlled to be in the range of 80 to 300 nm. When the retardation plate is used as the transparent protective film, the retardation plate also functions as the transparent protective film, and therefore, the thickness can be reduced.

Examples of the phase difference plate include: birefringent films obtained by uniaxially or biaxially stretching a polymer material, alignment films of liquid crystal polymers, retardation plates obtained by supporting alignment layers of liquid crystal polymers with films, and the like. The thickness of the retardation plate is not particularly limited, and is usually about 20 to 150 μm. Examples of the polymer raw material include: polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyacrylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyphenylene sulfide, polyphenylene ether, polyallylsulfonic acid, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornene resin), or various binary and ternary copolymers, graft copolymers, mixtures thereof, and the like. These polymer materials are formed into an oriented product (stretched film) by stretching or the like.

Examples of the liquid crystal polymer include: and various liquid crystal polymers of main chain type and side chain type in which conjugated linear atomic groups (mesogens) for imparting liquid crystal alignment properties are introduced into the main chain and side chain of the polymer. Specific examples of the main chain type liquid crystal polymer include polyester type liquid crystal polymers, discotic polymers, cholesteric polymers, and the like having a structure in which mesogenic groups are bonded through a spacer portion imparting flexibility, for example, having nematic alignment. Specific examples of the side chain type liquid crystal polymer include liquid crystal polymers having a main chain skeleton of polysiloxane, polyacrylate, polymethacrylate, or polyacrylate and a mesogenic portion having a side chain made of a para-substituted cyclic compound unit having nematic orientation imparting properties through a spacer portion made of a conjugated atomic group. These liquid crystal polymers are, for example, liquid crystal polymers obtained by polishing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, liquid crystal polymers obtained by oblique deposition of silicon oxide, or the like, and a solution of the liquid crystal polymer is developed on the alignment-treated surface and heat-treated.

The retardation plate may be, for example, various wave plates, a retardation plate having a suitable retardation depending on the purpose of use, for example, coloring by birefringence of a liquid crystal layer, compensation of a viewing angle, or the like, or a retardation plate in which 2 or more kinds of retardation plates are laminated to control optical characteristics such as a retardation.

The phase difference plate can be selected for various uses using a phase difference plate satisfying the relationship of nx > ny > nz, nx > nz > ny, nz > nx > ny, and nz > nx > ny. Incidentally, ny ═ nz includes not only the case where ny is completely the same as nz but also the case where ny is substantially the same as nz.

For example, among the retardation plates satisfying nx > ny > Nz, it is preferable to use a retardation plate in which the front retardation satisfies 40 to 100nm, the thickness direction retardation satisfies 100 to 320nm, and the Nz coefficient satisfies 1.8 to 4.5. For example, for a retardation film (positive A film) satisfying nx > ny ═ nz, a retardation film satisfying a front surface retardation of 100 to 200nm is preferably used. For example, for a retardation film (negative A plate) satisfying nz ═ nx > ny, a retardation film satisfying a front phase difference of 100 to 200nm is preferably used. For example, for a retardation film satisfying nx > Nz > ny, a retardation film satisfying a front surface retardation of 150 to 300nm and an Nz coefficient of more than 0 and less than 0.7 is preferably used. As described above, for example, a phase difference plate satisfying nx > ny > nz, nz > nx > ny, or nz > nx ═ ny can be used.

The transparent protective film may be appropriately selected depending on the liquid crystal display device to be used. For example, in the case of VA (Vertical Alignment, including MVA and PVA), at least one side (cell side) of the transparent protective film of the polarizing film preferably has a phase difference. The specific retardation is preferably in the range of 0 to 240nm in Re and 0 to 500nm in Rth. When described as a three-dimensional refractive index, nx > ny > nz, nx > nz > ny, and nx > ny > nz (positive a plate, biaxial plate, negative C plate) are preferable. In the VA mode, it is preferably used in the form of a combination of a positive a plate and a negative C plate, or 1 sheet of a bidirectional film. When polarizing films are used above and below the liquid crystal cell, the liquid crystal cell may have a phase difference between the upper and lower sides thereof or a phase difference between the upper and lower transparent protective films.

For example, the polarizing film can be used In any of the case of IPS (In-Plane Switching, including FFS), the case of a transparent protective film on one side of the polarizing film having a phase difference, and the case of no phase difference. For example, the case of not having a phase difference is preferably a case of not having a phase difference at the upper and lower sides (cell side) of the liquid crystal cell. The case of having a phase difference is preferably a case where both the upper and lower sides of the liquid crystal cell have a phase difference, or a case where either one of the upper and lower sides has a phase difference (for example, a case where the upper side has a two-way film satisfying nx > nz > ny, the lower side has no phase difference, or a case where the upper side has a positive a plate, and the lower side has a positive C plate). When the retardation is provided, Re-500 to 500nm and Rth-500 to 500nm are preferable. When expressed in terms of three-dimensional refractive index, nx > ny ═ nz, nx > nz > ny, nz > nx ═ ny, nz > nx > ny (positive a plate, biaxial, positive C plate) are preferred.

< easy adhesion composition >

The easy-adhesion composition used in the present invention preferably contains a compound represented by the following general formula (1),

[ chemical formula 4]

(wherein X is a functional group containing a reactive group, R¹And R²Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group). The aliphatic hydrocarbon group includes a linear or branched alkyl group having 1 to 20 carbon atoms and optionally having a substituent, a cyclic alkyl group having 3 to 20 carbon atoms and optionally having a substituent, and an alkenyl group having 2 to 20 carbon atoms, the aryl group includes a phenyl group having 6 to 20 carbon atoms and optionally having a substituent, a naphthyl group having 10 to 20 carbon atoms and optionally having a substituent, and the heterocyclic group includes, for example, a group having a 5-or 6-membered ring containing at least one hetero atom and optionally having a substituent. They may be connected to each other to form a ring. In the general formula (1), as R¹And R²The alkyl group is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms, and most preferably a hydrogen atom. The compound represented by the general formula (1) may be present in an unreacted state or in a state in which each functional group is reacted in the finally formed easy-adhesion layer.

X in the compound represented by the general formula (1) is a functional group containing a reactive group which is reactive with a curable component constituting the adhesive layer, and examples of the reactive group contained in X include: hydroxyl group, amino group, aldehyde group, carboxyl group, vinyl group, (meth) acryloyl group, styryl group, (meth) acrylamide group, vinyl ether group, epoxy group, oxetanyl group, α, β -unsaturated carbonyl group, mercapto group, halogen group, and the like. When the adhesive composition constituting the adhesive layer is active energy ray-curable, the reactive group contained in X is preferably at least 1 reactive group selected from a vinyl group, (meth) acryloyl group, styryl group, (meth) acrylamide group, vinyl ether group, epoxy group, oxetanyl group and mercapto group, and particularly when the adhesive composition constituting the adhesive layer is radical-polymerizable, the reactive group contained in X is preferably at least 1 reactive group selected from a (meth) acryloyl group, styryl group and (meth) acrylamide group, and when the compound represented by the general formula (1) has a (meth) acrylamide group, the reactivity is high, and the copolymerization rate with the active energy ray adhesive composition is increased, and thus is more preferable. In addition, since the (meth) acrylamide group has high polarity and excellent adhesiveness, it is also preferable from the viewpoint of efficiently obtaining the effects of the present invention. When the adhesive composition constituting the adhesive layer is cationically polymerizable, the reactive group contained in X preferably has at least 1 functional group selected from a hydroxyl group, an amino group, an aldehyde group, a carboxyl group, a vinyl ether group, an epoxy group, an oxetane group and a mercapto group, and particularly when the reactive group has an epoxy group, the obtained adhesive layer is excellent in adhesion to an adherend, and therefore, the adhesive composition is preferably excellent in curability when the adhesive layer has a vinyl ether group.

Preferable specific examples of the compound represented by the general formula (1) include a compound represented by the following general formula (1'),

[ chemical formula 5]

(wherein Y is an organic group, X, R¹And R²The same as described above). Further, the following compounds (1a) to (1d) can be suitably exemplified.

[ chemical formula 6]

In the present invention, the compound represented by the general formula (1) may be a compound in which a reactive group is directly bonded to a boron atom, but as shown in the above-mentioned specific examples, the compound represented by the general formula (1) is preferably a compound in which a reactive group is bonded to a boron atom through an organic group, that is, a compound represented by the general formula (1'). When the compound represented by the general formula (1) is, for example, a compound bonded to a reactive group through an oxygen atom bonded to a boron atom, the water-resistant adhesiveness of the polarizing film tends to be deteriorated. On the other hand, the compound represented by the general formula (1) is preferable because it has no boron-oxygen bond, has a boron-carbon bond by bonding to an organic group via a boron atom, and contains a reactive group (in the general formula (1'), since the water-resistant adhesiveness of the polarizing film is improved. The organic group specifically means an organic group having 1 to 20 carbon atoms which may have a substituent, and more specifically, examples thereof include: a linear or branched alkylene group having 1 to 20 carbon atoms and optionally having a substituent, a cyclic alkylene group having 3 to 20 carbon atoms and optionally having a substituent, a phenylene group having 6 to 20 carbon atoms and optionally having a substituent, a naphthylene group having 10 to 20 carbon atoms and optionally having a substituent, and the like.

Examples of the compound represented by the general formula (1) include, in addition to the above-mentioned compounds, esters of boric acid and (meth) acrylic acid esters such as an ester of hydroxyethyl acrylamide, an ester of boric acid and hydroxymethyl acrylamide, an ester of hydroxyethyl acrylate, and an ester of boric acid and hydroxybutyl acrylate.

When the content of the compound represented by the general formula (1) in the easy-adhesion composition is too small, the proportion of the compound represented by the general formula (1) present on the surface of the easy-adhesion layer may decrease, and the easy-adhesion effect may decrease. Therefore, the content of the compound represented by the general formula (1) in the easy adhesion composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. In addition, the content of the compound represented by the general formula (1) in the easy adhesion composition is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less.

In addition, the easy adhesion composition preferably contains an organometallic compound having an M-O bond in the structural formula (M is silicon, titanium, aluminum or zirconium, and O is an oxygen atom). The organometallic compound may be present in an unreacted state or in a state in which each functional group is reacted in the finally formed easy-adhesion layer.

The organometallic compound has an M-O bond (M is silicon, titanium, aluminum or zirconium, and O is an oxygen atom) in the structural formula. The organometallic compound is preferably at least 1 selected from the group consisting of an organosilicon compound, a metal alkoxide, and a metal chelate.

The organic silicon compound is not particularly limited, and an organic silicon compound having an Si — O bond can be used, and specific examples thereof include an active energy ray-curable organic silicon compound and an inactive energy ray-curable organic silicon compound. It is particularly preferable that the organic group of the organosilicon compound has 3 or more carbon atoms. Specific examples of the active energy ray-curable compound include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane are preferred.

As the non-active energy ray-curable compound, a compound having an amino group is preferable. Specific examples of the compound having an amino group include γ -aminopropyltrimethoxysilane, γ -aminopropyltriethoxysilane, γ -aminopropyltriisopropoxysilane, γ -aminopropylmethyldimethoxysilane, γ -aminopropylmethyldiethoxysilane, γ - (2-aminoethyl) aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropylmethyldimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropylmethyldiethoxysilane, γ - (2-aminoethyl) aminopropyltriisopropoxysilane, γ - (2- (2-aminoethyl) aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ -aminopropyltrimethoxysilane, γ -aminopropyltriethoxysilane, γ -alkoxysilane, γ -aminopropyltrimethoxysilane, γ -trimethoxysilane, γ -aminopropyltriethoxysilane, γ -trimethoxysilane, γ -triethoxysilane, γ -aminopropyltriethoxysilane, Gamma- (6-aminohexyl) aminopropyltrimethoxysilane, 3- (N-ethylamino) -2-methylpropyltrimethoxysilane, gamma-ureidopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, N-benzyl-gamma-aminopropyltrimethoxysilane, amino-containing silanes such as N-vinylbenzyl-gamma-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl) aminomethyltrimethoxysilane, and N, N' -bis [3- (trimethoxysilyl) propyl ] ethylenediamine; ketimine-type silanes such as N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine.

Only 1 kind of the compound having an amino group may be used, or a plurality of kinds may be used in combination. Of these, γ -aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropylmethyldimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropylmethyldiethoxysilane and N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine are preferable for ensuring good adhesion.

Specific examples of the non-active energy ray-curable compound other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and imidazolesilane.

The metal alkoxide is a compound in which at least one alkoxy group as an organic group is bonded to a metal, and the metal chelate is a compound in which an organic group is bonded or coordinated to a metal via an oxygen atom. As the metal, titanium, aluminum, and zirconium are preferable. Among them, aluminum and zirconium are more reactive than titanium, and the pot life of the easy-adhesion composition is shortened and the effect of improving the water resistant adhesion is sometimes lowered. Therefore, from the viewpoint of improving the water-resistant adhesion of the adhesive layer, titanium is more preferable as the metal of the organic metal compound.

When the easy adhesion composition contains a metal alkoxide as the organometallic compound, a metal alkoxide having an organic group of the metal alkoxide and preferably having 3 or more carbon atoms, more preferably 6 or more carbon atoms is used. When the number of carbon atoms is 2 or less, the pot life of the easy-adhesion composition may be shortened and the effect of improving the water resistant adhesion may be reduced. Examples of the organic group having 6 or more carbon atoms include an octyloxy group, and these groups can be suitably used. Suitable metal alkoxides include, for example: tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate, tert-amyl titanate, tetra-tert-butyl titanate, tetrastearyl titanate, zirconium tetraisopropoxide, zirconium tetrabutoxide, zirconium tetraoctanol, zirconium tetra-tert-butoxide, zirconium tetrapropanolate, aluminum sec-butoxide, aluminum ethoxide, aluminum isopropoxide (aluminum isopropoxide), aluminum butoxide (aluminum butoxide), aluminum diisopropoxide mono-sec-butoxide (aluminum diisopropoxide monobutoxide), aluminum mono-sec-butoxide (mono-butoxy diisopropoxide), and the like. Among them, tetraoctyl titanate is preferable.

When the easy adhesion composition contains a metal chelate as the organometallic compound, it is preferable that the easy adhesion composition contains a metal chelate in which the number of carbon atoms of an organic group contained in the metal chelate is 3 or more. When the number of carbon atoms is 2 or less, the pot life of the easy-adhesion composition may be shortened, and the effect of improving the water-resistant adhesion of the polarizing film may be reduced. Examples of the organic group having 3 or more carbon atoms include: acetylacetonato, acetoacetoxyethyl, isostearate, octanediol, and the like. Among these, from the viewpoint of improving the water-resistant adhesion of the adhesive layer, an acetylacetonato group or an acetoacetoxyethyl group is preferable as the organic group. Suitable metal chelates are, for example: titanium acetylacetonate, titanium octanedioxide, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium polyhydroxystearate, dipropoxybis (acetylacetonato) titanium, dibutoxytitanium bis (octanedioxide), dipropoxytitanium bis (ethylacetoacetate), titanium lactate, titanium diethanolamine, titanium triethanolamine, dipropoxytitanium bis (lactate), dipropoxytitanium bis (triethanolamine), di-n-butoxytitanium bis (triethanolamine), tri-n-butoxytitanium monostearate, diisopropoxybis (ethylacetoacetate) titanium, diisopropoxybis (acetoacetate) titanium, diisopropoxybis (acetylacetonato) titanium, titanium phosphate compound, titanium ammonium salt, titanium-1, 3-propanedioxybis (ethylacetoacetate), dodecylbenzenesulfonic acid compound, aminoethylaminotitanium ethoxide, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, Zirconium bisacetoacetate, zirconium acetate, zirconium tri-n-butoxyacetoacetonate, zirconium di-n-butoxybis (ethylacetoacetate), zirconium n-butoxytris (ethylacetoacetate), zirconium tetra (n-propyl acetoacetate), zirconium tetra (acetoacetoacetate), zirconium tetra (ethylacetoacetate), aluminum ethylacetoacetate, aluminum acetylacetonate, aluminum bisacetoacetate, aluminum diisopropoxylacetoacetate, aluminum isopropoxybis (ethylacetoacetate), aluminum isopropoxybis (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum tris (acetylacetonate), aluminum monoacetylacetonate bis (ethylacetoacetate). Among them, titanium acetylacetonate and titanium ethyl acetoacetate are preferable.

As the organometallic compound that can be used in the present invention, in addition to the above, there can be mentioned: zinc chelate compounds such as organic carboxylic acid metal salts such as zinc octanoate, zinc laurate, zinc stearate, and tin octanoate, zinc acetylacetonate chelate compounds, zinc benzoylacetonate chelate compounds, zinc dibenzoylmethane chelate compounds, and zinc ethyl acetoacetate chelate compounds.

When the content of the organometallic compound in the easy-to-bond composition is too small, the proportion of the organometallic compound present on the surface of the easy-to-bond layer may be reduced, and the easy-to-bond effect may be lowered. Therefore, the content of the organometallic compound in the easy adhesion composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. In addition, the content of the organometallic compound in the easy-adhesion composition is usually 10% by mass or less, preferably 5% by mass or less.

The easy-adhesion composition preferably contains an SP value of 21.0 (MJ/m)³)^1/2Above and 26.0 (MJ/m)³)^1/2The following polymerizable compound X is used as a curable component.

The polymerizable compound X is a compound having a radically polymerizable group such as a (meth) acrylate group and an SP value of 21.0 (MJ/m)³)^1/2Above and 26.0 (MJ/m)³)^1/2The following compounds can be used without limitation. Examples of the polymerizable compound X include: acryloyl morpholine (SP value 22.9), N-methoxy methacrylic acid amide (SP value 22.9), N-ethoxy methacrylic acid amide (SP value 22.3), and the like. As the polymerizable compound X, commercially available products can be suitably used, and examples thereof include ACMO (manufactured by Shikino corporation, SP value 22.9), Wasmer 2MA (manufactured by Chimaphila corporation, SP value 22.9), Wasmer EMA (manufactured by Chimaphila corporation, SP value 22.3), and Wasmer 3MA (manufactured by Chimaphila corporation, SP value 22.4). These may be used in 1 kind, or 2 or more kinds may be used in combination. Of these, acryloyl morpholine is preferably used.

Hereinafter, a method of calculating the SP value (solubility parameter) in the present invention will be described.

(method of calculating solubility parameter (SP value))

In the present invention, the solubility parameter (SP value) of the polymerizable compound X is determined by calculation using a Fedors calculation method [ see "Polymer Eng. & Sci.)" volume 14, No. 2 (1974), pages 148 to 154 ],

[ mathematical formula 1]

(wherein. DELTA.ei is the evaporation energy at 25 ℃ attributed to an atom or group, and. DELTA.vi is the molar volume at 25 ℃).

Δ ei and Δ vi in the above numerical formulae represent certain numerical values given to i atoms and groups in the main molecule. In addition, the numerical values of Δ e and Δ v assigned to atoms or groups are shown in table 1 below.

[ Table 1]

Atom or group	Δe(J/mol)	Δv(cm³/mol)
			CH₃	4086	33.5
C	1465	-19.2
			Phenyl radical	31940	71.4
Phenylene radical	31940	52.4
			COOH	27628	28.5
CONH₂	41861	17.5
			NH₂	12558	19.2
-N＝	11721	5.0
			CN	25535	24.0
NO₂(fatty acid)	29302	24.0
			NO₃(aromatic)	15363	32.0
O	3349	3.8
			OH	29805	10.0
S	14149	12.0
			F	4186	18.0
Cl	11553	24.0
			Br	15488	30.0

The content of the polymerizable compound X in the easy-adhesion composition is not particularly limited, but is preferably 20 mass% or more, more preferably 30 mass% or more, from the viewpoint of suppressing excessive penetration of the polymerizable compound X into the transparent protective film by blending the polymerizable compound X blended in the adhesive composition into the easy-adhesion composition, as described above, and is preferably 85 mass% or less, more preferably 75 mass% or less, from the viewpoint of imparting a thickening effect by allowing the polymerizable compound X blended in the adhesive composition to penetrate into the transparent protective film. The content of the polymerizable compound X in the easy-adhesion composition is adjusted in consideration of the content of the polymerizable compound X in the adhesive composition so that the total content of the easy-adhesion composition (excluding the solvent) and the polymerizable compound X in the adhesive composition is preferably 40 to 64 mass%, more preferably 50 to 62 mass%, and still more preferably 53 to 61 mass%.

The easy-bonding composition may contain a solvent and an additive.

The solvent is preferably a solvent capable of stably dissolving or dispersing the compound represented by the general formula (1) and the organometallic compound. The solvent may be an organic solvent, water, or a mixed solvent thereof. The solvent may be selected from, for example: esters such as ethyl acetate, butyl acetate, and 2-hydroxyethyl acetate; ketones such as methyl ethyl ketone, acetone, cyclohexanone, methyl isobutyl ketone, diethyl ketone, methyl n-propyl ketone, and acetylacetone; tetrahydrofuran (THF), bis

Cyclic ethers such as alkanes; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; toluene, xylene and the likeAromatic hydrocarbons; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol and cyclohexanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol monoethyl ether; glycol ether acetates such as diethylene glycol monomethyl ether acetate and diethylene glycol monoethyl ether acetate; and so on. Of these, water is preferably used.

When the easy-adhesion composition contains an organic solvent, the content of the organic solvent is preferably 5 to 80% by mass, more preferably 10 to 50% by mass, when the total amount of the easy-adhesion composition is 100% by mass, from the viewpoint of improving both the adhesion between the polarizer and the adhesive layer and the coatability. In addition, when the easy adhesion composition contains water, the content of water is preferably 5 to 90% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 60% by mass, from the viewpoint of improving the reactivity of the boron-containing compound with the functional group of the polarizer and improving the adhesion between the polarizer and the adhesive layer, when the total amount of the easy adhesion composition is 100% by mass.

Examples of the additives include: binder resin, surfactant, plasticizer, tackifier, low molecular weight polymer, polymerizable monomer, surface lubricant, leveling agent, antioxidant, preservative, light stabilizer, ultraviolet absorber, polymerization inhibitor, silane coupling agent, titanium coupling agent, inorganic or organic filler, metal powder, particle, foil, etc.

When the easy-adhesion composition contains a polymerization initiator, the polymerizable compound X or the boron-containing compound in the easy-adhesion composition may react, and the effect of improving the water-resistant adhesion of the polarizing film may not be sufficiently obtained. Therefore, the content of the polymerization initiator in the easy-adhesion composition is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably no polymerization initiator is contained.

< adhesive composition >

The adhesive composition can be cured in a form roughly classified into a heat curing form and an active energy ray curing form. Examples of the resin constituting the thermosetting adhesive composition include polyvinyl alcohol resin, epoxy resin, unsaturated polyester, urethane resin, acrylic resin, urea resin, melamine resin, phenol resin, and the like, and a curing agent is used in combination as necessary. As the resin constituting the thermosetting adhesive composition, a polyvinyl alcohol resin or an epoxy resin is more preferably used. The active energy ray-curable adhesive composition can be classified into electron beam-curable, ultraviolet-curable, and visible light-curable ones based on the classification of active energy rays. The curing forms can be classified into radical polymerizable adhesive compositions and cationic polymerizable adhesive compositions. In the present invention, the active energy ray having a wavelength of 10nm to 380nm is referred to as ultraviolet ray, and the active energy ray having a wavelength of 380nm to 800nm is referred to as visible ray.

In the production of the polarizing film of the present invention, the adhesive composition is preferably curable with active energy rays. Further, visible light curability by visible light of 380nm to 450nm is particularly preferable.

Examples of the curable component contained in the radical polymerizable adhesive composition include radical polymerizable compounds used in radical polymerizable adhesive compositions. Examples of the radical polymerizable compound include compounds having a radical polymerizable functional group having a carbon-carbon double bond such as a (meth) acryloyl group or a vinyl group. Any of monofunctional radical polymerizable compounds and difunctional or higher polyfunctional radical polymerizable compounds can be used as the curable component. These radical polymerizable compounds may be used alone in 1 kind, or in combination with 2 or more kinds. As these radical polymerizable compounds, for example, compounds having a (meth) acryloyl group are preferable. In the present invention, (meth) acryloyl means acryloyl and/or methacryloyl, and "(meth)" means the same as defined below.

Examples of the monofunctional radical polymerizable compound include compounds represented by the following general formula (2),

[ chemical formula 7]

(wherein, R³Is a hydrogen atom or a methyl group, R⁴And R⁵Each independently is a hydrogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group or a cyclic ether group, R⁴And R⁵Optionally forming a cyclic heterocyclic ring). The number of carbon atoms of the alkyl moiety of the alkyl group, hydroxyalkyl group, and/or alkoxyalkyl group is not particularly limited, and may be, for example, 1 to 4. In addition, R⁴And R⁵Examples of the optionally formed cyclic heterocyclic ring include N-acryloylmorpholine and the like.

Specific examples of the compound represented by the general formula (2) include: n-alkyl group-containing (meth) acrylamide derivatives such as N-methyl (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-hexyl (meth) acrylamide; n-hydroxyalkyl (meth) acrylamide-containing derivatives such as N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, and N-methylol-N-propyl (meth) acrylamide; and N-alkoxy group-containing (meth) acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide. Examples of the cyclic ether group-containing (meth) acrylamide derivative include heterocyclic ring-containing (meth) acrylamide derivatives in which the nitrogen atom of the (meth) acrylamide group forms a heterocyclic ring, and examples thereof include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among these, N-hydroxyethyl acrylamide and N-acryloyl morpholine can be suitably used in view of excellent reactivity, obtaining a cured product with a high elastic modulus, and excellent adhesion to a polarizer.

The adhesive composition used in the present invention preferably contains the polymerizable compound X as a curable component.

The content of the polymerizable compound X in the adhesive composition is not particularly limited, but is preferably 80% by mass or less, more preferably 60% by mass or less, from the viewpoint of suppressing excessive penetration of the polymerizable compound X into the transparent protective film, and is preferably 25% by mass or more, more preferably 35% by mass or more, from the viewpoint of improving the adhesiveness between the adhesive layer and the transparent protective film, as described above. The content of the polymerizable compound X in the adhesive composition is adjusted in consideration of the content of the polymerizable compound X in the easy-adhesion composition so that the total content of the easy-adhesion composition (excluding the solvent) and the polymerizable compound X in the adhesive composition is preferably 40 to 64 mass%, more preferably 50 to 62 mass%, and still more preferably 53 to 61 mass%.

The adhesive composition used in the present invention may contain a monofunctional radical polymerizable compound other than the above as a curable component. Examples of the monofunctional radical polymerizable compound include various (meth) acrylic acid derivatives having a (meth) acryloyloxy group. Examples of the (meth) acrylic acid derivative include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, (C1-20) alkyl (meth) acrylates such as t-amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, hexadecyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and n-octadecyl (meth) acrylate.

Further, examples of the (meth) acrylic acid derivative include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate, hydroxy-containing (meth) acrylates such as [4- (hydroxymethyl) cyclohexyl ] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether; halogen-containing (meth) acrylates such as 2,2, 2-trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate; alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; oxetanyl (meth) acrylates such as 3-oxetanyl methyl (meth) acrylate, 3-methyloxetanyl methyl (meth) acrylate, 3-ethyloxetanyl methyl (meth) acrylate, 3-butyloxetanyl methyl (meth) acrylate, and 3-hexyloxetanyl methyl (meth) acrylate; and (meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate and butyrolactone (meth) acrylate, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adducts, and p-phenylphenol (meth) acrylate. Among them, dicyclopentenyloxyethyl acrylate and phenoxyethyl acrylate are preferable because they have excellent adhesion to various protective films.

Examples of the (meth) acrylic acid derivative include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate, hydroxy-containing (meth) acrylates such as [4- (hydroxymethyl) cyclohexyl ] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether; halogen-containing (meth) acrylates such as 2,2, 2-trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate; alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; oxetanyl (meth) acrylates such as 3-oxetanyl methyl (meth) acrylate, 3-methyloxetanyl methyl (meth) acrylate, 3-ethyloxetanyl methyl (meth) acrylate, 3-butyloxetanyl methyl (meth) acrylate, and 3-hexyloxetanyl methyl (meth) acrylate; and (meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate and butyrolactone (meth) acrylate, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adducts, and p-phenylphenol (meth) acrylate. Among them, 2-hydroxy-3-phenoxypropyl acrylate is preferable because it has excellent adhesion to various protective films.

Examples of the monofunctional radical polymerizable compound include: carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

Examples of the monofunctional radical polymerizable compound include: lactam-type vinyl monomers such as N-vinylpyrrolidone, N-vinyl-caprolactam, and methyl vinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinylpyridine

Vinyl monomers having a nitrogen-containing heterocycle such as oxazole and vinyl morpholine.

When the adhesive composition used in the present invention contains a hydroxyl group-containing (meth) acrylate, a carboxyl group-containing (meth) acrylate, a phosphoric group-containing (meth) acrylate, or the like having high polarity among monofunctional radical polymerizable compounds, the adhesive force to various substrates is improved. The content of the hydroxyl group-containing (meth) acrylate is preferably 1 to 30% by mass relative to the adhesive composition. When the content of the hydroxyl group-containing (meth) acrylate is too large, the water absorption of the cured product may be high, and the water resistance may be poor. The content of the carboxyl group-containing (meth) acrylate is preferably 1 to 20% by mass relative to the adhesive composition. When the content of the carboxyl group-containing (meth) acrylate is too large, the optical durability of the polarizing film is lowered, which is not preferable. The phosphoric group-containing (meth) acrylate includes 2- (meth) acryloyloxyethyl acid phosphate, and the content thereof is preferably 0.1 to 10% by mass relative to the adhesive composition. When the content of the phosphoric group-containing (meth) acrylate is too large, the optical durability of the polarizing film is lowered, which is not preferable.

As the monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active methylene group and an active double bond group such as a (meth) acrylic group at a terminal or in a molecule. Examples of the active methylene group include: acetoacetyl, alkoxymalonyl, cyanoacetyl, or the like. The active methylene group is preferably an acetoacetyl group. Examples of the radical polymerizable compound having an active methylene group include: acetoacetoxyethyl alkyl (meth) acrylates such as 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxyethyl propyl (meth) acrylate, and 2-acetoacetoxyethyl-1-methylethyl (meth) acrylate; 2-ethoxymalonyloxyethyl (meth) acrylate, 2-cyanoacetoxyethyl (meth) acrylate, N- (2-cyanoacetoxyethyl) acrylamide, N- (2-propionylacetyloxybutyl) acrylamide, N- (4-acetoacetoxyethylmethylbenzyl) acrylamide, N- (2-acetoacetylaminoethyl) acrylamide and the like. The radical polymerizable compound having an active methylene group is preferably acetoacetoxyethyl (meth) acrylate.

Further, examples of the bifunctional or higher polyfunctional radical polymerizable compound include: n as a polyfunctional (meth) acrylamide derivative,n' -methylenebis (meth) acrylamide, tripropylene glycol di (meth) Acrylate, tetraethylene glycol di (meth) Acrylate, 1, 6-hexanediol di (meth) Acrylate, 1, 9-nonanediol di (meth) Acrylate, 1, 10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di (meth) Acrylate, bisphenol A ethylene oxide adduct di (meth) Acrylate, bisphenol A propylene oxide adduct di (meth) Acrylate, bisphenol A diglycidyl ether di (meth) Acrylate, neopentyl glycol di (meth) Acrylate, tricyclodecanedimethanol di (meth) Acrylate, Cyclic Trimethylolpropane formal (meth) Acrylate (Cyclic trimethyolpropane for maleic acid), II

Esters of (meth) acrylic acid and polyhydric alcohol such as alkanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and EO-modified diglycerol tetra (meth) acrylate, and 9, 9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl]Fluorene. As specific examples, ARONIX M-220 (manufactured by Toyo Seisaku-Sho Co., Ltd.), LIGHT ACRYLATE 1,9ND-A (manufactured by Kyowa Kagaku K.K.), LIGHT ACRYLATE DGE-4A (manufactured by Kyowa Kagaku K.K.), LIGHT ACRYLATE DCP-A (manufactured by Kyowa Kagaku K.K.), SR-531 (manufactured by Sartomer Co., Ltd.), CD-536 (manufactured by Sartomer Co., Ltd.) and the like are preferable. Further, as necessary, there may be mentioned: various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like. The polyfunctional (meth) acrylamide derivative is preferably contained in the adhesive composition because it has a high polymerization rate and excellent productivity and also has excellent crosslinkability when the adhesive composition is produced into a cured product.

From the viewpoint of satisfying both of the adhesiveness to polarizers and various transparent protective films and the optical durability in a severe environment, it is preferable to use a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound in combination as the radical polymerizable compound. Since the monofunctional radical polymerizable compound has a low liquid viscosity, the liquid viscosity of the adhesive composition can be reduced by adding the monofunctional radical polymerizable compound to the adhesive composition. Further, the monofunctional radical polymerizable compound often has a functional group that can exhibit various functions, and by including the monofunctional radical polymerizable compound in the adhesive composition, various functions can be exhibited in the adhesive composition and/or the cured product of the adhesive composition. The polyfunctional radical polymerizable compound is preferably contained in the adhesive composition because it can 3-dimensionally crosslink a cured product of the adhesive composition. The polyfunctional radical polymerizable compound is preferably used in an amount of 10 to 1000 parts by mass per 100 parts by mass of the monofunctional radical polymerizable compound.

When the active energy ray is an electron beam, the radical polymerizable adhesive composition does not necessarily contain a photopolymerization initiator, and when the active energy ray is ultraviolet light or visible light, the radical polymerizable adhesive composition preferably contains a photopolymerization initiator.

The photopolymerization initiator in the case of using a radical polymerizable compound can be appropriately selected depending on the active energy ray. In the case of curing by ultraviolet rays or visible light, a photopolymerization initiator that is cleaved by ultraviolet rays or visible light is used. Examples of the photopolymerization initiator include: benzophenone compounds such as benzil, benzophenone, benzoylbenzoic acid, and 3, 3' -dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α -hydroxy- α, α' -dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α -hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, etc.; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; optically active oximes such as 1-phenyl-1, 1-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-dichlorothioxanthone, 2, 4-diethylthioxanthone, 2, 4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; a halogenated ketone; acyl phosphine oxides; acyl phosphonates and the like.

The amount of the photopolymerization initiator added to the adhesive composition is preferably 20% by mass or less, more preferably 0.01 to 20% by mass, even more preferably 0.05 to 10% by mass, and particularly preferably 0.1 to 5% by mass. The content of the photopolymerization initiator in the adhesive composition is adjusted in consideration of the content of the photopolymerization initiator in the easy-adhesion composition so that the total content of the easy-adhesion composition (excluding the solvent) and the photopolymerization initiator in the adhesive composition is preferably 2.6 to 7% by mass, more preferably 2.65 to 6% by mass, and still more preferably 2.7 to 5% by mass.

When the adhesive composition used in the present invention is used for visible light curing containing a radical polymerizable compound as a curable component, it is particularly preferable to use a photopolymerization initiator having high sensitivity to light of 380nm or more. The photopolymerization initiator having high sensitivity to light of 380nm or more will be described later.

As the photopolymerization initiator, it is preferable to use a compound represented by the following general formula (3) alone or a compound represented by the general formula (3) in combination with a photopolymerization initiator having high sensitivity to light of 380nm or more,

[ chemical formula 8]

(in the formula, R⁶And R⁷represents-H, -CH₂CH₃-iPr or Cl, R⁶And R⁷May be the same or different). In useThe compound represented by the general formula (3) has excellent adhesion as compared with the case where a photopolymerization initiator highly sensitive to light of 380nm or more is used alone. Among the compounds represented by the general formula (3), R is particularly preferable⁶And R⁷is-CH₂CH₃Diethyl thioxanthone (ll). The composition ratio of the compound represented by the general formula (3) in the adhesive composition is preferably 0.1 to 5% by mass, more preferably 0.5 to 4% by mass, and still more preferably 0.9 to 3% by mass, relative to the total amount of the adhesive composition.

Further, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiation aid include: triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc., with ethyl 4-dimethylaminobenzoate being particularly preferred. When the polymerization initiator is used, the amount thereof added is usually 0 to 5% by mass, preferably 0 to 4% by mass, and most preferably 0 to 3% by mass, based on the total amount of the curable resin composition.

Further, a known photopolymerization initiator may be used in combination as necessary. Since the transparent protective film having UV absorption ability does not transmit light of 380nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380nm or more as the photopolymerization initiator. Specifically, there may be mentioned: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, bis (. eta.5-2, 4-cyclopentadien-1-yl) bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium and the like.

In particular, as the photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (3), a compound represented by the following general formula (4) is preferably further used,

[ chemical formula 9]

In the formula, R⁸、R⁹And R¹⁰represents-H, -CH₃、-CH₂CH₃-iPr or Cl, R⁸、R⁹And R¹⁰May be the same or different. As the compound represented by the general formula (4), commercially available 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907 manufacturer: BASF) can be suitably used. Further, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (trade name: IRGACURE369 manufacturer: BASF), 2- (dimethylamino) -2- [ (4-methylphenyl) methyl group]-1- [4- (4-morpholinyl) phenyl]-1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferred because of its high sensitivity.

In the adhesive composition, when a radical polymerizable compound having an active methylene group is used as the radical polymerizable compound, it is preferable to use a radical polymerization initiator having a hydrogen abstraction action in combination. According to this configuration, the adhesiveness of the adhesive layer of the polarizing film is significantly improved even immediately after the polarizing film is taken out from a high-humidity environment or from water (in an undried state). The reason is not clear, but is considered to be the following reason. That is, the radical polymerizable compound having an active methylene group is polymerized together with other radical polymerizable compounds constituting the adhesive layer, and enters the main chain and/or side chain of the base polymer in the adhesive layer to form the adhesive layer. In this polymerization process, if a radical polymerization initiator having a hydrogen abstraction action is present, a base polymer constituting the adhesive layer is formed, and hydrogen is abstracted from a radical polymerizable compound having an active methylene group, thereby generating a radical in the methylene group. The methylene group that generates a radical reacts with a hydroxyl group of a polarizer such as PVA to form a covalent bond between the adhesive layer and the polarizer. As a result, it is presumed that the adhesiveness of the adhesive layer of the polarizing film is significantly improved particularly in a non-dried state.

In the present invention, examples of the radical polymerization initiator having a hydrogen abstraction action include: thioxanthoneRadical polymerization initiators, benzophenone radical polymerization initiators, and the like. The radical polymerization initiator is preferably a thioxanthone radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include compounds represented by the above general formula (3). Specific examples of the compound represented by the general formula (3) include: thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone, and the like. Among the compounds represented by the general formula (3), R is particularly preferable⁶And R⁷is-CH₂CH₃Diethyl thioxanthone (ll).

When the adhesive composition contains a radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action, the radical polymerizable compound having an active methylene group is preferably contained in an amount of 1 to 50% by mass and the radical polymerization initiator in an amount of 0.1 to 10% by mass, based on the total amount of the adhesive composition, assuming that the total amount of the curable components is 100% by mass.

As described above, in the present invention, in the presence of a radical polymerization initiator having a hydrogen abstraction action, a radical is generated from a methylene group of a radical polymerizable compound having an active methylene group, and the methylene group reacts with a hydroxyl group of a polarizer such as PVA to form a covalent bond. Therefore, in order to generate radicals from the methylene group of the radical polymerizable compound having an active methylene group and to form the covalent bond sufficiently, the radical polymerizable compound having an active methylene group is preferably contained in an amount of 1 to 50% by mass, more preferably 3 to 30% by mass, based on 100% by weight of the total amount of the curable components. In order to sufficiently improve the water resistance and the adhesiveness in a non-dried state, it is preferable to set the radical polymerizable compound having an active methylene group to 1% by mass or more. On the other hand, if it exceeds 50 mass%, poor curing of the adhesive layer may occur. The radical polymerization initiator having a hydrogen abstraction action is preferably contained in an amount of 0.1 to 10% by mass, more preferably 0.3 to 9% by mass, based on the total amount of the adhesive composition. In order to sufficiently progress the hydrogen abstraction reaction, it is preferable to use 0.1% by mass or more of a radical polymerization initiator. On the other hand, if it exceeds 10% by mass, the solvent may not be completely dissolved in the composition.

The adhesive composition used in the present invention preferably further contains the following components as necessary.

In the present invention, the adhesive composition may contain a compound represented by the above general formula (1), preferably a compound represented by the above general formula (1'), and more preferably compounds represented by the above general formulae (1a) to (1 d). In the present invention, the above-mentioned organometallic compound may be blended in the adhesive composition. When these compounds are blended in the adhesive composition, the adhesiveness to the polarizer and the transparent protective film may be improved, and therefore, the composition is preferable. The content of the compound represented by the general formula (1) in the adhesive composition is preferably 0.001 to 50% by mass, more preferably 0.1 to 30% by mass, and even more preferably 1 to 10% by mass, from the viewpoint of improving the adhesiveness and water resistance when the polarizer and the transparent protective film are adhered to each other with the adhesive layer interposed therebetween. In the adhesive composition, the content of the organometallic compound is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and still more preferably 1 to 5% by mass.

The bubble inhibitor is a compound capable of reducing the surface tension by being incorporated into the adhesive composition, and has an effect of reducing bubbles between the adhesive composition and the transparent protective film to be bonded. As the bubble inhibitor, for example: silicone bubble inhibitors having a polysiloxane skeleton such as polydimethylsiloxane, (meth) acrylic bubble inhibitors having a (meth) acryloyl skeleton obtained by polymerizing (meth) acrylic acid esters or the like, polyether bubble inhibitors obtained by polymerizing vinyl ethers, cyclic ethers or the like, fluorine bubble inhibitors comprising fluorine-containing compounds having perfluoroalkyl groups, and the like.

The bubble suppressant preferably has a reactive group in the compound. In this case, when the polarizer and the transparent protective film are bonded, the generation of lamination bubbles can be reduced. The reactive group of the bubble inhibitor includes a polymerizable functional group, and specifically includes, for example, a radical polymerizable functional group having an olefinic double bond such as a (meth) acryloyl group, a vinyl group, or an allyl group, a cationic polymerizable functional group such as an epoxy group such as a glycidyl group, an oxetane group, a vinyl ether group, a cyclic thioether group, or a lactone group. From the viewpoint of reactivity in the adhesive composition, a bubble suppressing agent having a double bond as a reactive group is preferable, and a bubble suppressing agent having a (meth) acryloyl group is more preferable.

Among the above-mentioned bubble suppressing agents, silicone-based bubble suppressing agents are preferable in consideration of the laminated bubble suppressing effect and the adhesion improving effect. Among the bubble suppressing agents, those containing a urethane bond or an isocyanurate ring structure in the main chain skeleton or side chain are preferable in view of the adhesiveness of the adhesive layer. As the silicone bubble inhibitor, a commercially available product can be suitably used, and examples thereof include BYK-UV3505 (BYK-Chemie Japan) which is an acryl-modified polydimethylsiloxane.

In order to achieve both the adhesive strength of the resulting adhesive layer and the effect of reducing laminated bubbles, the content of the bubble inhibitor is preferably 0.01 to 0.6% by mass, based on 100% by mass of the total amount of the adhesive composition.

The adhesive composition used in the present invention may contain an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer, in addition to the curable component of the radical polymerizable compound. By including the acrylic oligomer in the adhesive composition, the curing shrinkage when the composition is cured by irradiation with active energy rays can be reduced, and the interface stress between the adhesive and an adherend such as a polarizer and a transparent protective film can be reduced. As a result, the adhesive layer can be prevented from being deteriorated in adhesiveness to the adherend. In order to sufficiently suppress the curing shrinkage of the adhesive layer, the content of the acrylic oligomer is preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the adhesive composition. When the content of the acrylic oligomer in the adhesive composition is too large, the reaction rate when the composition is irradiated with an active energy ray may be rapidly reduced, and curing may be poor. On the other hand, the acrylic oligomer is contained in an amount of preferably 3% by mass or more, more preferably 5% by mass or more, based on the total amount of the adhesive composition.

In view of workability and uniformity in application, the adhesive composition preferably has a low viscosity, and therefore an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer is also preferably low in viscosity. The weight average molecular weight (Mw) of the low-viscosity acrylic oligomer capable of preventing curing shrinkage of the adhesive layer is preferably 15000 or less, more preferably 10000 or less, and particularly preferably 5000 or less. On the other hand, in order to sufficiently suppress curing shrinkage of the adhesive layer, the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and particularly preferably 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer include: (meth) acrylic acid (C1-20) alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, tert-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and n-octadecyl (meth) acrylate, And for example: cycloalkyl (meth) acrylates (e.g., cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), (aralkyl (meth) acrylates (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (e.g., 2-isobornyl (meth) acrylate, 2-norbornyl methyl (meth) acrylate, 5-norborn-2-ylmethyl (meth) acrylate, 3-methyl-2-norbornyl methyl (meth) acrylate, etc.), hydroxyl-containing (meth) acrylates (e.g., hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2, 3-dihydroxypropylmethylbutyl (meth) acrylate, etc.), alkoxy-or phenoxy-containing (meth) acrylates ((2-methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, etc.), 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, and the like, epoxy group-containing (meth) acrylates (e.g., glycidyl (meth) acrylate, and the like), halogen-containing (meth) acrylates (e.g., 2,2, 2-trifluoroethyl (meth) acrylate, 2,2, 2-trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl (meth) acrylates (e.g., dimethylaminoethyl (meth) acrylate, etc.), and the like. These (meth) acrylates may be used singly or in combination of 2 or more. Specific examples of the acrylic oligomer include "ARUFON" manufactured by east asia synthetic co., ltd, "ACTFLOW" manufactured by seiko chemical co., ltd, "JONCRYL" manufactured by BASF Japan ltd.

The adhesive composition may contain a photoacid generator. When the adhesive composition contains the photoacid generator, the water resistance and durability of the adhesive layer can be greatly improved as compared with the case where the photoacid generator is not contained. The photoacid generator can be represented by the following general formula (5).

General formula (5)

[ chemical formula 10]

L⁺X^-

(in the formula, L⁺Means of being arbitrary

A cation. In addition, X^-Is selected from PF₆ ^-、SbF₆ ^-、AsF₆ ^-、SbCl₆ ^-、BiCl₅ ^-、SnCl₆ ^-、ClO₄ ^-Dithiocarbamate anion, SCN^-The counter anion of (1). )

Next, for the counter anion X in the general formula (5)^-To carry outAnd (4) explanation.

In principle on the counter anion X in the general formula (5)^-The anion is not particularly limited, but a non-nucleophilic anion is preferable. When the counter anion X is a non-nucleophilic anion, the photoacid generator represented by the general formula (5) itself and a composition using the same can be improved in stability with time because a nucleophilic reaction of a cation coexisting in a molecule and various materials used in combination is not easily caused. The term "non-nucleophilic anion" as used herein refers to an anion having a low ability to cause nucleophilic reaction. Examples of such anions include: PF (particle Filter)₆ ^-、SbF₆ ^-、AsF₆ ^-、SbCl₆ ^-、BiCl₅ ^-、SnCl₆ ^-、ClO₄ ^-Dithiocarbamate anion, SCN^-And the like.

Specifically, the "CYRACURE UVI-6992", "CYRACURE UVI-6974" (manufactured by Dow chemical Japan Limited, supra), "Adekaoptomer SP 150", "Adekaoptomer SP 152", "Adekaoptomer SP 170", "Adekaoptomer SP 172" (manufactured by Dow chemical Co., Ltd), "IRGACURE 250" (manufactured by Ciba specialty Chemicals Inc.), "CI-5102", "CI-2855" (manufactured by Nippon Soda Co., Ltd), "San-Aid SI-60L", "San-Aid SI-80L", "San-Aid SI-100L", "San-Aid SI-110L", "San-Aid SI-180L" (manufactured by Sanxin Co., Ltd), "CPI-100P" (manufactured by Sanco., Ltd), "WPI-113" WPI-6974 "(manufactured by Sanco., WPI-101L)," WPI-116 WPI-116 "manufactured by Sanxin Corp, Japan", and "WPI-100A" (manufactured by Sanp-100L, manufactured by Sanp-Aid Chemicals Corp Ltd., "WPI-100L", "WPI-113", and "WPI-116, "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", and "WPAG-596" (both manufactured by Wako pure chemical industries, Ltd.) are preferable examples of the photoacid generator of the present invention.

The content of the photoacid generator is 10% by mass or less, more preferably 0.01 to 10% by mass, still more preferably 0.05 to 5% by mass, and particularly preferably 0.1 to 3% by mass, based on the total amount of the adhesive composition.

The photobase generator is a compound that changes the molecular structure or cleaves the molecule by irradiation with light such as ultraviolet light or visible light to generate 1 or more basic substances that function as a catalyst for the polymerization reaction of a radical polymerizable compound or an epoxy resin. Examples of the basic substance include secondary amines and tertiary amines. Examples of the photobase generator include the α -aminoacetophenone compound described above, the oxime ester compound described above, and a compound having a substituent such as an acyloxyimino group, an N-formylated aromatic amino group, an N-acylated aromatic amino group, a nitrobenzylcarbamate group, or an alkoxybenzylcarbamate group. Among them, oxime ester compounds are preferable.

Examples of the acyloxyimino group-containing compound include: o, O '-succinic acid diphenyl acetoxime, O' -succinic acid dinaphthobenzene oxime, and diphenyl ketone oxime acrylate-styrene copolymer.

Examples of the compound having an N-formylated aromatic amino group and an N-acylated aromatic amino group include: di-N- (p-formylamino) diphenylmethane, di-N- (p-acetylamino) diphenylmethane, di-N- (p-benzoylamino) diphenylmethane, 4-formylaminostilbene, 4-acetylaminostilbene, 2, 4-diformylaminostilbene, 1-formylaminonaphthalene, 1-acetylaminonaphthalene, 1, 5-diformylaminonaphthalene, 1-formylaminoanthracene, 1, 4-diformylaminoanthracene, 1-acetylaminoanthracene, 1, 4-diformylaminoanthraquinone, 1, 5-diformylaminoanthraquinone, 3 ' -dimethyl-4, 4 ' -diformylaminobiphenyl, 4 ' -diformylaminobenzophenone.

Examples of the compound having a nitrobenzyl carbamate group and an alkoxybenzyl carbamate group include: bis { (2-nitrobenzyl) oxy } carbonyl } diaminodiphenylmethane, 2, 4-bis { (2-nitrobenzyl) oxy } stilbene, bis { (2-nitrobenzyloxy) carbonyl } hexane-1, 6-diamine, o-xylidine { (2-nitro-4-chlorobenzyl) oxy } amide }.

The photobase generator is preferably at least any 1 selected from an oxime ester compound and an alpha-aminoacetophenone compound, and more preferably an oxime ester compound. As the α -aminoacetophenone compound, an α -aminoacetophenone compound having 2 or more nitrogen atoms is particularly preferable.

As other photobase generators, WPBG-018 (trade name, 9-anthrylmethyl-N, N' -diethylcarbamate), WPBG-027 (trade name, (E) -1- [3- (2-hydroxyphenyl) -2-acryloyl ] piperidine ((E) -1- [3- (2-hydroxyphenyl) -2-propenoyl ] piperidine)), and photobase generators such as WPBG-082 (trade name, guanidinium2- (3-benzoylphenyl) propionate 2- (3-benzoylphenyl) propionate), WPBG-140 (trade name, 1- (anthraquinone-2-yl) ethylimidazolium carboxylate (1- (anthraquinon-2-yl) ethyl imidazolium carboxylate)).

In the adhesive composition, a photoacid generator and a compound containing either an alkoxy group or an epoxy group may be used in combination in the adhesive composition.

When a compound having 1 or more epoxy groups in a molecule or a polymer (epoxy resin) having 2 or more epoxy groups in a molecule is used, a compound having two or more functional groups reactive with epoxy groups in a molecule may be used in combination. Among them, examples of the functional group reactive with an epoxy group include: carboxyl, phenolic hydroxyl, mercapto, primary or secondary aromatic amino, and the like. In view of three-dimensional curability, it is particularly preferable to have 2 or more of these functional groups in one molecule.

Examples of the polymer having 1 or more epoxy groups in the molecule include epoxy resins including bisphenol a type epoxy resins derived from bisphenol a and epichlorohydrin, bisphenol F type epoxy resins derived from bisphenol F and epichlorohydrin, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol a novolac type epoxy resins, bisphenol F novolac type epoxy resins, alicyclic epoxy resins, diphenyl ether type epoxy resins, hydroquinone type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, fluorene type epoxy resins, 3-functional epoxy resins, polyfunctional epoxy resins such as 4-functional epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, aliphatic chain epoxy resins, and the like, these epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resin products include: JER code 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000, EPICLON830, EXA835LV, HP4032D, HP820, EP4100 series manufactured by ADEKA, EP4000 series, EPU series, Daicel Chemical Industries, CELLOXIDE series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by Ltd, Epolead series, EHPE series, YD series, YDF series, YDCN series, YDB series, phenoxy resins (polyhydroxy polyethers synthesized from bisphenols and epichlorohydrin and having Epoxy groups at both ends; YP series, etc.) manufactured by Nagamtse Chemicals, Decolon series, Corporation, etc., but not limited thereto. These epoxy resins may be used in combination of 2 or more

The compound having an alkoxy group in the molecule is not particularly limited as long as it has 1 or more alkoxy groups in the molecule, and known compounds can be used. Typical examples of such compounds include melamine compounds, amino resins, and silane coupling agents.

The amount of the compound containing either an alkoxy group or an epoxy group is usually 30% by mass or less based on the total amount of the adhesive composition, and if the content of the compound in the composition is too large, the adhesiveness is lowered and the impact resistance in the drop weight test may be deteriorated. The content of the compound in the composition is more preferably 20% by mass or less. On the other hand, from the viewpoint of water resistance, the compound is preferably contained in the composition in an amount of 2% by mass or more, more preferably 5% by mass or more.

When the adhesive composition used in the present invention is active energy ray-curable, an active energy ray-curable compound is preferably used as the silane coupling agent, but the same water resistance can be provided even if the silane coupling agent is not active energy ray-curable.

Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-vinyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane, which are active energy ray-curable compounds.

As a specific example of the non-active energy ray-curable silane coupling agent, a silane coupling agent having an amino group is preferable. Specific examples of the silane coupling agent having an amino group include γ -aminopropyltrimethoxysilane, γ -aminopropyltriethoxysilane, γ -aminopropyltriisopropoxysilane, γ -aminopropylmethyldimethoxysilane, γ -aminopropylmethyldiethoxysilane, γ - (2-aminoethyl) aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropylmethyldimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropylmethyldiethoxysilane, γ - (2-aminoethyl) aminopropyltriisopropoxysilane, γ - (2- (2-aminoethyl) aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropyltriisopropoxysilane, γ - (2-aminoethyl) aminopropyltrimethoxysilane, Gamma- (6-aminohexyl) aminopropyltrimethoxysilane, 3- (N-ethylamino) -2-methylpropyltrimethoxysilane, gamma-ureidopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, N-benzyl-gamma-aminopropyltrimethoxysilane, amino-containing silanes such as N-vinylbenzyl-gamma-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl) aminomethyltrimethoxysilane, and N, N' -bis [3- (trimethoxysilyl) propyl ] ethylenediamine; ketimine-type silanes such as N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine.

Only 1 kind of the silane coupling agent having an amino group may be used, or a plurality of kinds may be used in combination. Of these, γ -aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropylmethyldimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropylmethyldiethoxysilane and N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine are preferable for ensuring good adhesion.

The amount of the silane coupling agent is preferably in the range of 0.01 to 20% by mass, more preferably 0.05 to 15% by mass, and still more preferably 0.1 to 10% by mass, based on the total amount of the adhesive composition. This is because the storage stability of the adhesive composition is deteriorated when the blending amount is more than 20% by mass, and the effect of the water resistant adhesion is hardly exhibited when the blending amount is less than 0.1% by mass.

Specific examples of the non-active energy ray-curable silane coupling agent other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and imidazolesilane.

When the adhesive composition used in the present invention contains a compound having a vinyl ether group, the water-resistant adhesion between the polarizer and the adhesive layer is improved, and therefore, the adhesive composition is preferable. The reason for obtaining this effect is not clear, but it is presumed that one of the reasons is that the adhesion between the polarizer and the adhesive layer is improved by the interaction between the vinyl ether group of the compound and the polarizer. In order to further improve the water-resistant adhesion between the polarizer and the adhesive layer, the compound is preferably a radical polymerizable compound having a vinyl ether group. The content of the compound is preferably 0.1 to 19% by mass based on the total amount of the adhesive composition.

The adhesive composition used in the present invention may contain a compound that causes keto-enol tautomerism. For example, in an adhesive composition containing a crosslinking agent or an adhesive composition that can be used in combination with a crosslinking agent, a mode including the compound that causes keto-enol tautomerism can be preferably employed. This can suppress excessive viscosity increase, gelation, and formation of a microgel product in the adhesive composition after the organometallic compound is compounded, and can achieve the effect of extending the pot life of the composition.

As the above-mentioned compound which causes keto-enol tautomerism, various β -dicarbonyl compounds can be used. Specific examples thereof include: beta-diketones such as acetylacetone, 2, 4-hexanedione, 3, 5-heptanedione, 2-methylhexane-3, 5-dione, 6-methylheptane-2, 4-dione, and 2, 6-dimethylheptane-3, 5-dione; acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate; propionyl acetates such as methyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, and tert-butyl propionyl acetate; isobutyryl acetic acid esters such as methyl isobutyrylacetate, ethyl isobutyrylacetate, isopropyl isobutyrylacetate, and tert-butyl isobutyrylacetate; malonic esters such as methyl malonate and ethyl malonate; and so on. Among these, acetylacetone and acetoacetates are suitable examples. The above-mentioned keto-enol tautomerism-generating compounds may be used alone, or 2 or more thereof may be used in combination.

The amount of the compound which causes keto-enol tautomerism can be, for example, 0.05 to 10 parts by mass, preferably 0.2 to 3 parts by mass (for example, 0.3 to 2 parts by mass) with respect to 1 part by mass of the organometallic compound. If the amount of the above compound used is less than 0.05 part by mass relative to 1 part by mass of the organometallic compound, it may be difficult to exhibit sufficient use effects. On the other hand, if the amount of the compound used is more than 10 parts by mass relative to 1 part by weight of the organometallic compound, the compound excessively interacts with the organometallic compound and it may become difficult to exhibit the intended water resistance.

The adhesive composition of the present invention may contain polyrotaxane. The polyrotaxane has a cyclic molecule, a linear molecule passing through an opening of the cyclic molecule, and a blocking group disposed at both ends of the linear molecule so that the cyclic molecule is not detached from the linear molecule. The cyclic molecule preferably has an active energy ray-curable functional group.

The cyclic molecule is not particularly limited as long as it has an opening including a linear molecule in a chain form, is movable on the linear molecule, and has an active energy ray-polymerizable group. In the present specification, the term "cyclic" of a "cyclic molecule" means substantially "cyclic". That is, the cyclic molecule may not be completely closed as long as it can move on the linear molecule.

Specific examples of the cyclic molecule include cyclic polymers such as cyclic polyethers, cyclic polyesters, cyclic polyetheramines, and cyclic polyamines, and cyclodextrins such as α -cyclodextrin, β -cyclodextrin, and γ -cyclodextrin. Among these, cyclodextrins such as α -cyclodextrin, β -cyclodextrin, and γ -cyclodextrin, which are relatively easily available and can be selected from a large number of types of capping groups, are preferable. The cyclic molecule may be present in a mixture of 2 or more kinds in the polyrotaxane or the binder.

In the polyrotaxane used in the present invention, the cyclic molecule has an active energy ray-polymerizable group. Thus, the polyrotaxane reacts with the active energy ray-curable component, and the adhesive in which the crosslinking point moves even after curing is obtained. The active energy ray-polymerizable group of the cyclic molecule may be any group that can be polymerized with the active energy ray-curable compound, and examples thereof include radical-polymerizable groups such as a (meth) acryloyl group and a (meth) acryloyloxy group.

When cyclodextrin is used as the cyclic molecule, it is preferable that the active energy ray-polymerizable group is introduced to a hydroxyl group of cyclodextrin via an arbitrary appropriate linker. The number of active energy ray-polymerizable groups in 1 molecule of polyrotaxane is preferably 2 to 1280, more preferably 50 to 1000, and further preferably 90 to 900.

It is preferable to introduce a hydrophobic modification group into the cyclic molecule. By introducing a hydrophobic modification group, the compatibility with the active energy ray-curable component can be improved. Further, since the polarizing film is provided with hydrophobicity, when used for a polarizing film, water can be prevented from entering the interface between the adhesive layer and the polarizer, and water resistance can be further improved. Examples of the hydrophobic modification group include a polyester chain, a polyamide chain, an alkyl chain, an oxyalkylene chain, and an ether chain. Specific examples thereof include those described in paragraphs [0027] to [0042] of WO 2009/145073.

Polarizing films using a polyrotaxane-containing resin composition as an adhesive have excellent water resistance. The reason why the water resistance of the polarizing film is improved is not known, but is presumed as follows. That is, it is considered that the crosslinked points can move due to the mobility of the cyclic molecules of the polyrotaxane (so-called pulley effect), thereby imparting flexibility to the cured adhesive and increasing the adhesion to the surface irregularities of the polarizer, and as a result, water is prevented from entering the interface between the polarizer and the adhesive layer. Further, it is considered that the hydrophobic property can be imparted to the adhesive by imparting a hydrophobic property to the polyrotaxane, which also contributes to preventing water from entering the interface between the polarizer and the adhesive layer. The content of the polyrotaxane is preferably 2 to 50% by mass based on the resin composition.

In the present invention, a cationically polymerizable adhesive composition can be used for forming the adhesive layer. The cationic polymerizable compound used in the cationic polymerizable adhesive composition can be classified into a monofunctional cationic polymerizable compound having 1 cationic polymerizable functional group in the molecule and a polyfunctional cationic polymerizable compound having 2 or more cationic polymerizable functional groups in the molecule. Since the monofunctional cationic polymerizable compound has a low liquid viscosity, the liquid viscosity of the adhesive composition can be reduced by adding the monofunctional cationic polymerizable compound to the adhesive composition. Further, the monofunctional cationic polymerizable compound often has a functional group that can exhibit various functions, and by including the monofunctional cationic polymerizable compound in the adhesive composition, various functions can be exhibited in the adhesive composition and/or the cured product of the adhesive composition. The polyfunctional cationic polymerizable compound is preferably contained in the adhesive composition because it can 3-dimensionally crosslink a cured product of the adhesive composition. The ratio of the monofunctional cationic polymerizable compound to the polyfunctional cationic polymerizable compound is preferably in the range of 10 parts by mass to 1000 parts by mass based on 100 parts by mass of the monofunctional cationic polymerizable compound. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group and a vinyl ether group. Examples of the compound having an epoxy group include an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound, and since the compound has excellent curability and adhesiveness, it is particularly preferable to contain an alicyclic epoxy compound as the cationically polymerizable adhesive composition of the present invention. Examples of the alicyclic epoxy compound include 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate, caprolactone-modified products of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate, trimethylcaprolactone-modified products, valerolactone-modified products, and the like, and specifically include CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE2083, CELLOXIDE 2085 (the above is made by Dailuo Chemical industries Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, R-6110 (the above is made by Dow Chemical Japan Ltd.). The cationic polymerizable adhesive composition of the present invention preferably contains a compound having an oxetanyl group because of its effect of improving curability and reducing liquid viscosity of the composition. Examples of the oxetanyl group-containing compound include 3-ethyl-3-hydroxymethyloxetane, 1, 4-bis [ (3-ethyl-3-oxetanyl) methoxymethyl ] benzene, 3-ethyl-3- (phenoxymethyl) OXETANE, bis [ (3-ethyl-3-oxetanyl) methyl ] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) OXETANE, novolak OXETANE and the like, and ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221 and ARON OXETANE OXT-212 (available from Toyo Kabushiki Kaisha) are commercially available. The cationic polymerizable adhesive composition of the present invention preferably contains a compound having a vinyl ether group because of its effect of improving curability and reducing liquid viscosity of the composition. Examples of the compound having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol-type tetravinyl ether, and the like.

The cationically polymerizable adhesive composition contains at least 1 compound selected from the compounds having an epoxy group, oxetane group and vinyl ether group described above as a curable component, and all of them are cured by cationic polymerization, and thus a photo cationic polymerization initiator is blended. The photo cation polymerization initiator generates a cation species or lewis acid by irradiation of active energy rays such as visible light, ultraviolet rays, X-rays, electron beams, etc., thereby initiating a polymerization reaction of an epoxy group or an oxetanyl group. As the photo cation polymerization initiator, a photo acid generator and a photo base generator can be used, and a photo acid generator described later can be suitably used. In addition, in the case of using the adhesive composition used in the present invention as the visible light-curable, it is particularly preferable to use a photo cation polymerization initiator having high sensitivity to light of 380nm or more, but since the photo cation polymerization initiator is a compound which usually exhibits maximum absorption in the vicinity of 300nm or a wavelength region shorter than 300nm, by blending a photosensitizer which exhibits maximum absorption in light of a wavelength region longer than that, specifically, longer than 380nm, it is possible to sense light of a wavelength in the vicinity thereof and promote generation of cationic species or acid from the photo cation polymerization initiator. As the photosensitizer, for example: anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, sulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducing pigments, etc., and these may be mixed with 2 or more of them. Particularly, anthracene compounds are preferable because they are excellent in photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass,

in addition, various additives may be added to the adhesive composition used in the present invention as other optional components within a range not impairing the object and effect of the present invention. Examples of the additive include polymers or oligomers such as epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadienes, polychloroprenes, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, cellulose resins, fluorine-based oligomers, silicone-based oligomers, and polythioether-based oligomers; polymerization inhibitors such as phenothiazine and 2, 6-di-tert-butyl-4-methylphenol; a polymerization initiation aid; leveling agent; a wettability modifier; a surfactant; a plasticizer; an ultraviolet absorber; an inorganic filler; a pigment; dyes, and the like.

When the adhesive composition is applied to the surface having the convex portion of the transparent protective film, the viscosity of the adhesive composition at the time of application is preferably 0.5 to 100 mPas, more preferably 1 to 50 mPas, in order to suppress the incorporation of bubbles into the periphery of the convex portion. The viscosity of the adhesive composition at the time of application can be adjusted depending on the kinds, blending amounts, and the like of the curable component, acrylic oligomer, and additive used. The viscosity of the adhesive composition may be adjusted to the above range by adjusting the temperature of the adhesive composition at the time of application. The temperature of the adhesive composition during application is not particularly limited, but is preferably 15 to 40 ℃, and more preferably 20 to 35 ℃.

< method for producing polarizing film >

Hereinafter, each step in the method for producing a polarizing film of the present invention will be described.

The method for manufacturing a polarizing film of the present invention comprises: a coating step of coating an adhesive composition on the surface of the transparent protective film having the convex portion; a bonding step of bonding the polarizer and the transparent protective film; and an adhesion step of adhering the polarizer and the transparent protective film via an adhesive layer having a thickness of 1.6 μm or more obtained by curing the adhesive composition.

Preferably, the method for producing a polarizing film of the present invention further comprises a coating step of coating an easy-adhesive composition on the contact surface of the polarizer.

The polarizer and the transparent protective film may be subjected to surface modification treatment before the coating step. It is particularly preferable to perform surface modification treatment on the surface of the polarizer. Examples of the surface modification treatment include corona treatment, plasma treatment, excimer treatment, and flame treatment, and corona treatment is particularly preferable. By performing the corona treatment, reactive functional groups such as carbonyl groups and amino groups are formed on the polarizer surface, and the adhesiveness to the adhesive layer is improved. Further, impurities on the surface can be removed by the ashing effect, or unevenness on the surface can be reduced, whereby a polarizing film having excellent appearance characteristics can be produced.

< Process for applying easily bondable composition >

As a method of applying the easy-adhesion composition to the bonding surface of the polarizer, for example, a method of applying the easy-adhesion composition to the bonding surface of the polarizer is exemplified. The coating method is not particularly limited, and examples thereof include: roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating.

When the easy-adhesion composition contains a solvent, the easy-adhesion composition may be applied to the bonding surface of the polarizer and then subjected to a drying step as needed.

When the thickness of the easy adhesion composition layer (after drying) obtained by applying the easy adhesion composition is too large, the cohesive force of the easy adhesion layer obtained by curing the easy adhesion composition layer may be reduced, and the easy adhesion effect may be lowered. Therefore, the thickness of the easy adhesion composition layer (after drying) is preferably 1000nm or less, more preferably 800nm or less, and further preferably 600nm or less. On the other hand, in order to sufficiently exert the effect of the easy adhesion layer, the thickness of the easy adhesion composition layer (after drying) is usually 50nm or more, preferably 100nm or more, and more preferably 200nm or more.

< Process for applying adhesive composition >

The method of applying the adhesive composition to the support release surface side of the transparent protective film is appropriately selected depending on the viscosity of the adhesive composition and the target thickness, and examples thereof include: reverse coaters, gravure coaters (direct, reverse, or offset), bar reverse coaters, roll coaters, die coaters, wire wound bar coaters, and bar coaters, among others.

The adhesive composition is applied so that the thickness of the adhesive layer obtained by curing the adhesive composition becomes 1.6 μm or more, 2 μm or more, 3 μm or more, or 5 μm or more, depending on the height of the convex portion of the transparent protective film. In the case where the easy adhesion layer is formed on the bonding surface of the polarizer, the easy adhesion layer becomes a part of the adhesive layer, and therefore, the adhesive composition is applied so that the thickness of the adhesive layer including the easy adhesion layer becomes 1.6 μm or more.

< bonding Process >

The polarizer and the transparent protective film are bonded to each other by the adhesive composition (and the easy adhesive composition layer) applied as described above. The polarizer and the transparent protective film may be bonded to each other by a roll laminator or the like.

< bonding Process >

After the polarizer and the transparent protective film are bonded to each other, the adhesive composition (and the easily adhesive composition layer) is cured by irradiation with active energy rays (e.g., electron beams, ultraviolet rays, visible light, etc.) to form an adhesive layer. The irradiation direction of the active energy ray (e.g., electron beam, ultraviolet ray, visible light, etc.) may be any appropriate direction, and is preferably from the transparent protective film side. If the irradiation is performed from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beams, ultraviolet rays, visible light, and the like).

The irradiation conditions in the case of irradiating an electron beam may be any suitable conditions as long as the adhesive composition can be cured. For example, the acceleration voltage for electron beam irradiation is preferably 5kV to 300kV, and more preferably 10kV to 250 kV. If the acceleration voltage is less than 5kV, the electron beam may not reach the adhesive and may be insufficiently cured, and if the acceleration voltage is more than 300kV, the penetration force through the sample may be too strong and damage may be caused to the transparent protective film and the polarizer. The dose of the radiation is 5 to 100kGy, and more preferably 10 to 75 kGy. When the irradiation dose is less than 5kGy, the adhesive is insufficiently cured, and when it exceeds 100kGy, the transparent protective film and the polarizer are damaged, and the mechanical strength is reduced and the polarizer is yellowed, so that the optical characteristics cannot be obtained.

The electron beam irradiation is usually carried out in an inert gas, and may be carried out in an atmosphere with a small amount of oxygen introduced as required. Oxygen is introduced as appropriate depending on the material of the transparent protective film, and the surface of the transparent protective film which is in contact with the first electron beam is in contact with the oxygen, whereby oxygen inhibition occurs, damage to the transparent protective film can be prevented, and only the adhesive can be efficiently irradiated with an electron beam.

In the method for producing a polarizing film of the present invention, it is preferable to use, as the active energy ray, an active energy ray containing visible light having a wavelength range of 380nm to 450nm, particularly an active energy ray having the largest dose of visible light having a wavelength range of 380nm to 450 nm. When a transparent protective film (ultraviolet-opaque transparent protective film) having ultraviolet absorptivity and visible light absorption ability is used, light having a wavelength shorter than about 380nm is absorbed, and thus, light having a wavelength shorter than 380nm does not reach the adhesive composition, and does not contribute to the polymerization reaction. Further, light having a wavelength shorter than 380nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkling of the polarizing film. Therefore, in the present invention, when ultraviolet light or visible light is used, it is preferable to use a device that does not emit light having a wavelength shorter than 380nm as the active energy ray generating device, and more specifically, the ratio of the cumulative illuminance in the wavelength range of 380 to 440nm to the cumulative illuminance in the wavelength range of 250 to 370nm is preferably 100:0 to 100:50, and more preferably 100:0 to 100: 40. In the method for producing a polarizing film of the present invention, a gallium-sealed metal halide lamp or an LED light source emitting light in a wavelength range of 380 to 440nm is preferable as the active energy ray. Alternatively, a light source containing ultraviolet rays and visible light such as a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, an incandescent lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a gallium lamp, an excimer laser, or sunlight may be used, or ultraviolet rays having a wavelength shorter than 380nm may be blocked by a band-pass filter and used. In order to improve the adhesion performance of the adhesive layer between the polarizer and the transparent protective film and to prevent curling of the polarizing film, it is preferable to use a gallium-sealed metal halide lamp and to use an active energy ray having a wavelength of 405nm obtained by using a band-pass filter capable of blocking light having a wavelength shorter than 380nm or an LED light source.

The adhesive composition is preferably heated before irradiation with ultraviolet rays or visible light (heating before irradiation), and in this case, the adhesive composition is preferably heated to 40 ℃ or higher, more preferably to 50 ℃ or higher. In addition, it is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet rays or visible light (heating after irradiation), and in this case, it is preferable to heat the composition to 40 ℃ or higher, more preferably to 50 ℃ or higher.

The adhesive composition used in the present invention can be suitably used particularly when forming an adhesive layer in which a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365nm are adhered to each other. Here, the adhesive composition used in the present invention can be cured to form an adhesive layer by irradiating ultraviolet rays through a transparent protective film having UV absorbability with a photopolymerization initiator containing the photopolymerization initiator of the general formula (3) described above. Therefore, even in a polarizing film in which transparent protective films having UV absorbing ability are laminated on both surfaces of a polarizer, the adhesive layer can be cured. However, it is needless to say that the adhesive layer can be cured also for a polarizing film in which a transparent protective film having no UV absorbing ability is laminated. The transparent protective film having UV absorption ability means a transparent protective film having a transmittance of light of 380nm of less than 10%.

Examples of the method for imparting UV absorption capability to the transparent protective film include: a method of incorporating an ultraviolet absorber into a transparent protective film, and a method of laminating a surface treatment layer containing an ultraviolet absorber on the surface of a transparent protective film.

Specific examples of the ultraviolet absorber include: conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, triazine compounds, and the like.

When the polarizing film of the present invention is produced by a continuous production line, the line speed varies depending on the curing time of the adhesive composition, and is preferably 1 to 500m/min, more preferably 5 to 300m/min, and still more preferably 10 to 100 m/min. When the linear velocity is too low, productivity is lowered, and damage to the transparent protective film becomes large. When the line speed is too high, the curing of the adhesive composition may become insufficient, and the desired adhesiveness may not be obtained.

In order to produce a polarizing film free from spot white defects and free from local expansion on the surface of the transparent protective film, the thickness of the adhesive layer (including the easy-adhesion layer) must be 1.6 μm or more, preferably 2 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more. The upper limit of the thickness of the adhesive layer (including the easy-adhesion layer) is not particularly limited, but is preferably 10 μm or less, more preferably 7 μm or less, from the viewpoint of curability of the adhesive layer.

< optical film >

The polarizing film of the present invention can be practically used as an optical film laminated with another optical layer. The optical layer is not particularly limited, and examples thereof include: optical films such as retardation films (including wave plates such as 1/2 and 1/4), optical compensation films, brightness enhancement films, reflection plates, and reflection/transmission plates are optical layers used in the formation of liquid crystal display devices.

As the retardation film, a retardation film having a retardation of 40nm or more in the front direction and/or 80nm or more in the thickness direction can be used. The front retardation is usually controlled to be in the range of 40 to 200nm, and the thickness direction retardation is usually controlled to be in the range of 80 to 300 nm.

As the phase difference plate, there are: birefringent films obtained by uniaxially or biaxially stretching a polymer material, alignment films of liquid crystal polymers, retardation plates obtained by supporting alignment layers of liquid crystal polymers with films, and the like. The thickness of the retardation film is not particularly limited, and is generally about 20 to 150 μm.

As the retardation film, a reverse wavelength dispersion type retardation film satisfying the following formulas (1) to (3) can be used:

0.70＜Re[450]/Re[550]＜0.97···(1)

1.5×10^-3＜Δn＜6×10^-3···(2)

1.13＜NZ＜1.50···(3)

(wherein Re 450 and Re 550 are in-plane retardation values of the retardation film measured at 23 ℃ by light having wavelengths of 450nm and 550nm, respectively; Δ n is in-plane birefringence, nx-ny, where the refractive indices of the retardation film in the slow axis direction and the fast axis direction are nx and ny, respectively; NZ is the ratio of in-plane birefringence (nx-NZ), where NZ is the refractive index of the retardation film in the thickness direction, to the thickness-direction birefringence (nx-ny).

The polarizing film or the optical film having at least 1 polarizing film laminated thereon may be provided with an adhesive layer for adhesion to other members such as a liquid crystal cell. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and for example, polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine polymers, and rubbers can be suitably selected and used as the base polymer. In particular, a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive which is excellent in optical transparency, exhibits adhesive properties such as appropriate wettability, aggregability and adhesiveness, and is excellent in weather resistance, heat resistance and the like can be preferably used.

The adhesive layer may be provided on one side or both sides of the polarizing film, the optical film in the form of stacked layers of different compositions, kinds, or the like. In addition, when the polarizing film and the optical film are provided on both surfaces, adhesive layers having different compositions, kinds, thicknesses, and the like may be formed on the front and back surfaces of the polarizing film and the optical film. The thickness of the adhesive layer may be suitably determined depending on the purpose of use, adhesion, etc., and is usually 1 to 500. mu.m, preferably 1 to 200. mu.m, and particularly preferably 1 to 100. mu.m.

The exposed surface of the adhesive layer is temporarily covered with a separator by adhesion for the purpose of preventing contamination and the like until the adhesive layer is actually used. This prevents contact with the adhesive layer in a normal processing state. As the separator, a conventionally specified suitable separator such as a separator obtained by coating a suitable thin layer body such as a plastic film, a rubber sheet, paper, cloth, nonwoven fabric, a net, a foamed sheet, a metal foil, or a laminate thereof with a suitable release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide, if necessary, can be used in addition to the above thickness conditions.

< image display device >

The polarizing film or optical film of the present invention can be preferably used for formation of various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to a conventional method. That is, the liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell with a polarizing film or an optical film and, if necessary, components such as an illumination system, and incorporating a driver circuit, and the like. As the liquid crystal cell, any type of liquid crystal cell such as TN type, STN type, pi type, or the like can be used.

A suitable liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of a liquid crystal cell, a liquid crystal display device using a backlight or a reflector in an illumination system, or the like can be formed. In this case, the polarizing film or the optical film of the present invention may be disposed on one side or both sides of the liquid crystal cell. In the case where a polarizing film or an optical film is provided on both sides, they may be the same or different. Further, in the formation of the liquid crystal display device, appropriate members such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight may be disposed in appropriate positions in 1 layer or 2 layers or more.

Examples

Examples of the present invention are described below, but the embodiments of the present invention are not limited to these examples.

< polarizer >

First, a laminate in which a PVA layer having a thickness of 9 μm was formed on an amorphous PET substrate was subjected to auxiliary stretching in a gas atmosphere at a stretching temperature of 130 ℃ to form a stretched laminate, then the stretched laminate was dyed to form a colored laminate, and the colored laminate was further stretched in an aqueous boric acid solution at a stretching temperature of 65 ℃ so that the total stretching ratio was 5.94 times, integrally with the amorphous PET substrate, to form an optical film laminate including a PVA layer having a thickness of 5 μm. By such 2-step stretching, an optical film laminate comprising a PVA layer having a thickness of 5 μm, which constitutes a thin polarizer in which the PVA molecules of the PVA layer formed on the amorphous PET substrate are highly oriented and iodine adsorbed by dyeing is highly oriented in one direction in the form of a polyiodide complex, can be obtained. The moisture content of the thin polarizer (PVA layer) was 10 mass%.

< transparent protective film >

As the transparent protective film, a cellulose triacetate film (manufactured by Konika Minntau K.K.: KC2UA) having a thickness of 25 μm was used. The film is produced by a solution casting film forming method, and the surface (support peeling surface) of the film on the side from which the support for film formation is peeled has projections due to recesses such as scratches and pinholes present on the surface of the support for film formation.

< active energy ray >

As the active energy ray, a visible light (metal halide lamp in which gallium is sealed) irradiation device was used: fusion uv systems, inc. Light HAMMER10, valve: v valve, peak illuminance: 1600mW/cm²Cumulative dose of radiation 1000/mJ/cm²(wavelength 380-440 nm). The illuminance of visible light was measured by using the Sola-Check system manufactured by Solatell corporation.

< preparation of easily bondable composition >

An easy-adhesive composition was prepared by mixing 50 parts by mass of acryloylmorpholine (product name "ACMO" manufactured by KJ chemical Co., Ltd., SP value: 22.9) and 0.9 part by mass of 3-acrylamidophenylboronic acid (product name "Olfine EXP.4123") to obtain a mixture, stirring the mixture at 25 ℃ for 30 minutes, further mixing 48.3 parts by mass of water and 0.8 part by mass of a leveling agent (product name "Olfine EXP.4123") to the mixture, and stirring the mixture at 25 ℃ for 10 minutes.

Example 1

< preparation of adhesive composition >

Acrylmorpholine (product name "ACMO" manufactured by KJ chemical Co., Ltd., SP value: 22.9)45 parts by mass, 1, 9-nonanediol diacrylate (product name "LIGHT ACRYLATE 1.9.9 ND-A", manufactured by Kyoeisha chemical Co., Ltd.) 41 parts by mass, an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer (product name "ARON UG 4010", manufactured by Niya chemical Co., Ltd.), 10 parts by mass, diethylthioxanthone as a photoinitiator (the compound described in the general formula (3), the product name "KAYACUREDEX-S", manufactured by Nippon chemical Co., Ltd.), 1.5 parts by mass, and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one as a photopolymerization initiator (the compound described in the general formula (4), the product name "Omnirad 907"), IGM RESINS corporation) was mixed at 2.5 parts by mass and stirred at 50 ℃ for 1 hour, thereby preparing an adhesive composition. The viscosity of the adhesive composition thus prepared was measured at 25 ℃ using an E-type viscometer (TVE 22LT, manufactured by Toyobo industries Co., Ltd.), and was 15.3 mPas.

< production of polarizing film >

On a continuous production line, the prepared easy-adhesion composition was applied to the PVA surface of the optical film laminate containing a PVA layer having a thickness of 5 μm using a gravure roll coating method equipped with a gravure roll to form a coating film having a thickness of 1100nm, and then the coating film was dried using a dryer to form an easy-adhesion composition layer having a thickness of 550 nm.

On the other hand, in another continuous production line, the prepared adhesive composition (25 ℃) was applied to the release surface (surface having convex portions) of the support of the transparent protective film by a gravure roll coating method equipped with a gravure roll, and an adhesive composition layer having a thickness of 1500nm was formed.

Next, the bonding surface of the optical film laminate on which the easy adhesive composition layer is formed and the bonding surface of the transparent protective film on which the adhesive composition layer is formed are bonded to each other using a roll machine. Then, the polarizer and the transparent protective film were bonded via an adhesive layer (including an easy-adhesion layer) by irradiating the transparent protective film side to which the polarizer was bonded with the visible light from the active energy ray irradiation apparatus, and further, hot air drying was performed at 70 ℃ for 3 minutes to peel off and remove the amorphous PET substrate, thereby obtaining a polarizing film having a transparent protective film on the polarizer side. The thickness of the adhesive layer (including the easy adhesion layer) was 2050 nm.

Example 2

< preparation of adhesive composition >

An adhesive composition was prepared in the same manner as in example 1.

< production of polarizing film >

On a continuous production line, the prepared easy-adhesion composition was applied to the PVA surface of the optical film laminate containing a PVA layer having a thickness of 5 μm using a gravure roll coating method equipped with a gravure roll to form a coating film having a thickness of 950nm, and then the coating film was dried using a dryer to form an easy-adhesion composition layer having a thickness of 475 nm.

Then, a polarizing film was obtained in the same manner as in example 1. The thickness of the adhesive layer (including the easy adhesion layer) was 1975 nm.

Example 3

< preparation of adhesive composition >

Adhesive compositions were prepared in the same manner as in example 1, using the raw materials and the amounts thereof shown in table 2. The viscosity of the adhesive composition thus prepared was measured at 25 ℃ using an E-type viscometer (TVE 22LT, manufactured by Toyobo industries Co., Ltd.), and was 42 mPas. LIGHT ACRYLATE DCP-A in Table 2 is dimethylol tricyclodecane diacrylate (trade name: LIGHT ACRYLATE DCP-A; manufactured by Kyoeisha chemical Co., Ltd.).

< production of polarizing film >

Comparative example 1

< preparation of adhesive composition >

An adhesive composition was prepared in the same manner as in example 1.

< production of polarizing film >

On the other hand, in another continuous production line, the prepared adhesive composition (25 ℃) was applied to the release surface (surface having convex portions) of the support of the transparent protective film by a gravure roll coating method equipped with a gravure roll, and an adhesive composition layer having a thickness of 1100nm was formed.

Then, a polarizing film was obtained in the same manner as in example 1. The thickness of the adhesive layer (including the easy adhesion layer) was 1575 nm.

Reference example 1

< preparation of adhesive composition >

Adhesive compositions were prepared in the same manner as in example 1, using the raw materials and the amounts thereof shown in table 2. The viscosity of the adhesive composition thus prepared was measured at 25 ℃ using an E-type viscometer (TVE 22LT, manufactured by Toyobo industries Co., Ltd.), and was 109 mPas. LIGHT ACRYLATE DCP-A in Table 2 is dimethylol tricyclodecane diacrylate (trade name: LIGHT ACRYLATE DCP-A; manufactured by Kyoeisha chemical Co., Ltd.).

< production of polarizing film >

(evaluation of Spot white Spot Defect)

The obtained polarizing film was transmitted and projected onto a white screen 1m from the light source using a xenon lamp light source (model L8425-01, manufactured by Hamamatsu Photonics Co., Ltd.). Then, the projected image on the screen was observed, and the number of white spot defects reflected in a white spot shape was counted in the range of the projected image corresponding to the range of 1m × 1m of the polarizing film. The evaluation was performed in a dark room. The results are shown in Table 2.

(evaluation of swelling of surface of transparent protective film)

The polarizing film obtained was irradiated with light on the transparent protective film side under a fluorescent lamp, and the surface shape was observed from the reflected light reflected on the surface of the polarizing film. Then, the number of positions where the convex bulges were present among the positions reflected in the white spot shape in the above evaluation of the white spot defect was counted within a range of 1m × 1m on the surface of the polarizing film. The evaluation was performed in a dark room. The results are shown in Table 2.

(evaluation of bubbles)

The appearance of the obtained polarizing film was observed with an optical microscope, and the number of bubbles having a maximum diameter of 5 to 200 μm in the range of 5cm × 5cm was counted. The number of bubbles was 0 and 1 or more was evaluated as "o". The results are shown in Table 2.

[ Table 2]

Industrial applicability

The polarizing film of the present invention can be used alone or in the form of an optical film obtained by laminating the polarizing film in an image display device such as a Liquid Crystal Display (LCD), an organic EL display, a CRT, or a PDP.

Claims

1. A polarizing film comprising a polarizer and a transparent protective film provided on at least one surface of the polarizer via an adhesive layer,

one surface of the transparent protective film is a surface with a convex part,

the adhesive layer has a thickness of 1.6 [ mu ] m or more.

2. The polarizing film of claim 1,

the surface of the transparent protective film having the convex portion is a support peeling surface after peeling the support for film formation,

the convex portion is formed by a concave portion on the surface of the film-forming support.

3. The polarizing film according to claim 1 or 2,

the transparent protective film is a cellulose resin film.

4. The polarizing film according to any one of claims 1 to 3,

the thickness of the transparent protective film is 30 μm or less.

5. The polarizing film according to any one of claims 1 to 4,

the polarizer has an easy-adhesion layer on a bonding surface thereof, and the easy-adhesion layer is a part of the adhesive layer.

6. The polarizing film of claim 5,

the easy-adhesion composition as a material for forming the easy-adhesion layer contains a compound represented by the following general formula (1) and/or an organometallic compound having an M-O bond in the structural formula,

in the formula (1), X is a functional group containing a reactive group, R¹And R²Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group or a heterocyclic group,

m is silicon, titanium, aluminum or zirconium, and O is an oxygen atom.

7. The polarizing film of claim 6,

the compound represented by the general formula (1) is a compound represented by the following general formula (1'),

in the formula (1'), Y is an organic group, X, R¹And R²The same as above.

8. The polarizing film of claim 6 or 7,

the reactive group of the compound represented by the general formula (1) is at least 1 reactive group selected from an α, β -unsaturated carbonyl group, a vinyl ether group, an epoxy group, an oxetanyl group, an amino group, an aldehyde group, a mercapto group, and a halogen group.

9. The polarizing film according to any one of claims 6 to 8,

the easy-adhesion composition contains 21.0 (MJ/m) SP value³)^1/2Above and 26.0 (MJ/m)³)^1/2The following polymerizable compound X.

10. A method for producing a polarizing film having a transparent protective film provided on at least one surface of a polarizer with an adhesive layer interposed therebetween,

one surface of the transparent protective film is a surface with a convex part,

the method comprises the following steps:

11. The polarizing film production method according to claim 10,

12. The polarizing film production method according to claim 10 or 11,

the viscosity of the adhesive composition during coating is 0.5 to 100 mPas.

13. The method for manufacturing a polarizing film according to any one of claims 10 to 12, comprising:

a coating step of coating an easy-adhesion composition containing a compound represented by the following general formula (1) and/or an organometallic compound having an M-O bond in the structural formula on the bonding surface of the polarizer,

m is silicon, titanium, aluminum, or zirconium, and O is an oxygen atom.

14. The polarizing film production method according to claim 13,

15. An optical film having the polarizing film as set forth in any one of claims 1 to 9.

16. An image display device having the polarizing film according to any one of claims 1 to 9 or having the optical film according to claim 15.