KR20160107113A - Optical film with adhesive layer - Google Patents

Abstract

The purpose of the present invention is to provide an adhesive layer attached optical film having excellent durability, in which a display panel is not easily bent, and heat unevenness does not easily occur, even when an optical film to be thinned is used. To achieve the objective described above, an adhesive layer attached optical film (1A) comprises: a first retardation plate (11); a first adhesive layer (21) stacked on a plane of the first retardation plate (11); a second adhesive layer (22) stacked on a surface of the first retardation plate (11), opposite to a surface in which the first adhesive layer (21) is located; and a second retardation plate (12) stacked on a surface of the second adhesive layer (22), opposite to a surface in which the first retardation plate (11) is located. A surface of the first retardation plate (11), in contact with the first adhesive layer (21) is formed of an acrylic resin. According to the adhesive layer attached optical film (1A), a gel fraction of an adhesive forming the first adhesive layer (21) is 55-90%; a storage modulus (G) of the first adhesive layer (21) at 85C is 0.03-0.25 MPa; a gel fraction of an adhesive forming the second adhesive layer (22) is 80-100%; and a storage modulus (G) of the second adhesive layer (22) at 85C is 0.15-3.00 MPa.

Description

[0001] OPTICAL FILM WITH ADHESIVE LAYER [0002]

The present invention relates to an optical film with a pressure-sensitive adhesive layer, and more particularly to an optical film with a pressure-sensitive adhesive layer used for bonding an optical film such as a composite polarizing plate to a liquid crystal cell or the like.

2. Description of the Related Art Recently, a touch panel serving as both a display device and an input means has been widely used as a display panel of various electronic apparatuses. The types of touch panels are mainly resistive, capacitive, optical and ultrasonic. Resistive type is analog resistive type and matrix resistive type. Capacitive type is surface type and projection type.

BACKGROUND ART [0002] In a touch panel in a mobile electronic device such as a smart phone or a tablet terminal, which has recently attracted attention, a projection type capacitance type is widely used. As a projection type capacitive touch panel in such a mobile electronic device, for example, a liquid crystal display (LCD), a pressure sensitive adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO) A transparent conductive film (ITO), and a protective plate such as tempered glass are stacked.

As an optical component constituting the liquid crystal display device, a liquid crystal cell is generally used. In the liquid crystal cell, the alignment layers of the two transparent electrode substrates on which the alignment layers are formed are arranged in the inner side, spaced apart from each other by a spacer, and the periphery thereof is sealed to form a liquid crystal material . Usually, a polarizing plate or a composite polarizing plate having a retardation plate is adhered to the outside of the two transparent electrode substrates in a liquid crystal cell through a pressure-sensitive adhesive.

As an optical pressure-sensitive adhesive, for example, one disclosed in Patent Document 1 is known. The pressure-sensitive adhesive is preferably a (meth) acrylic polymer comprising, as a monomer unit, 0.2 to 20 parts by mass of a carboxyl group-containing monomer as a copolymerization component with respect to 100 parts by mass of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms, 0.02 to 2 parts by mass of a peroxide as a cross-linking agent, and 0.005 to 5 parts by mass of an epoxy cross-linking agent based on 100 parts by mass of the (meth) acryl-based polymer.

Patent Document 1: JP-A-2009-242786

In recent years, in accordance with a demand for thinning of mobile electronic devices, it has been required to thin optical films such as polarizing plates. However, the polarizing plate of the thin film has a high shrinkage rate due to heat and the like. In the conventional pressure sensitive adhesive such as Patent Document 1, the display panel is warped, and under high temperature or humid conditions, lifting and peeling occur. Further, it is pointed out that there is a problem that light leakage (so-called thermal unevenness) arises due to displacement of the optical axis of the optical film due to stress during heat shrinkage of the optical film.

The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide an optical film with a pressure-sensitive adhesive layer which is excellent in durability, does not bend the display panel well, and is unlikely to be thermally uneven, even when a thin optical film is used The purpose.

In order to achieve the above object, first, the present invention provides a polarizing plate comprising a first retardation plate, a first pressure-sensitive adhesive layer laminated on one side of the first retardation plate, and a second pressure- And a second retardation plate laminated on the side opposite to the side of the first retardation plate in the second pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer- , The surface of the first retarder plate that is in contact with the first pressure sensitive adhesive layer is made of acrylic resin and the gel fraction of the pressure sensitive adhesive constituting the first pressure sensitive adhesive layer is 55 to 90% (G ') at 85 ° C is 0.03 to 0.25 MPa, the gel fraction of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer is 80 to 100%, and the temperature of the second pressure- (G ') of from 0.15 to 3.00 MPa in terms of the storage elastic modulus (Claim 1).

According to the invention (Invention 1), even when the surface of the optical film which is in contact with the pressure-sensitive adhesive layer is made of acrylic resin and the optical film is made thin, the first pressure-sensitive adhesive layer and the second pressure- When used in a display panel, the display panel is excellent in durability, the display panel is not bent well, and thermal unevenness does not occur easily.

In the above invention (Invention 1), it is preferable that the outermost layer in contact with the first pressure-sensitive adhesive layer in the first retardation plate is made of an acrylic resin layer formed through extrusion molding (Invention 2).

In the above invention (Invention 2), it is preferable that the first retardation plate has the acrylic resin layer, the second acrylic resin layer, and the retardation layer located between the acrylic resin layer and the second acrylic resin layer (Invention 3).

In the above invention (Invention 3), it is preferable that the phase difference-generating layer is made of a styrenic resin (Invention 4).

In the above invention (Invention 1 to 4), it is preferable that the second retardation plate is made of a cyclic olefin resin (Invention 5).

In the above invention (Invention 1 to 5), the first pressure-sensitive adhesive layer is preferably a (meth) acrylate ester containing a monomer unit (a1) containing an alicyclic structure and a monomer (a2) (A) and a pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing a crosslinking agent (B) (invention 6).

In the invention (Invention 1 to 6), it is preferable that a polarizing plate is further laminated on the side of the second retardation plate opposite to the side of the second pressure-sensitive adhesive layer side (invention 7).

INDUSTRIAL APPLICABILITY According to the optical film with a pressure-sensitive adhesive layer of the present invention, even when the optical film is made thin, the durability is excellent, the display panel does not bend well, and the heat unevenness does not occur easily.

1 is a sectional view of an optical film with a pressure-sensitive adhesive layer according to an embodiment of the present invention.
2 is a cross-sectional view showing a configuration example of a retarder.
3 is a cross-sectional view of an optical film with a pressure-sensitive adhesive layer according to another embodiment of the present invention.
4 is a drawing (color) showing evaluation criteria of a heat-resistance non-uniformity test (visual observation) in an optical film with a pressure-sensitive adhesive layer.

Hereinafter, an embodiment of the present invention will be described.

[Optical film with pressure-sensitive adhesive layer according to the first embodiment]

1, the optical film (1A) with a pressure-sensitive adhesive layer according to the first embodiment of the present invention comprises a first retardation plate (11) and a second retardation plate (11) A first pressure sensitive adhesive layer 21 laminated on the first pressure sensitive adhesive layer 21 and a second pressure sensitive adhesive layer 21 laminated on the side of the first retardation plate 11 opposite to the side of the first pressure sensitive adhesive layer 21 Layer 22 and a second retardation plate 12 laminated on the side of the surface of the second pressure-sensitive adhesive layer 22 opposite to the side of the first retardation plate 11 side . The surface of the first retardation plate 11 that is in contact with the first pressure sensitive adhesive layer 21 is made of acrylic resin. The gel fraction of the pressure sensitive adhesive constituting the first pressure sensitive adhesive layer 21 is 55 to 90% and the storage elastic modulus G 'of the first pressure sensitive adhesive layer 21 at 85 캜 is 0.03 to 0.25 MPa. The gel fraction of the pressure sensitive adhesive constituting the second pressure sensitive adhesive layer 22 is 80 to 100% and the storage elastic modulus G 'of the second pressure sensitive adhesive layer 22 at 85 캜 is 0.15 to 3.00 MPa.

The optical film (1A) with a pressure-sensitive adhesive layer can be obtained by a method in which the optical film to be used (laminated body of the first retardation plate 11, the second pressure-sensitive adhesive layer 22 and the second retardation plate 12) Even when used in a display panel, it is excellent in durability and is prevented from being lifted or peeled off even under a high-temperature condition, a moist heat condition, or a heat shock. Further, the display panel does not bend well even under high temperature conditions, and there is no heat unevenness. This effect is mainly due to the fact that the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22 are each composed of a pressure-sensitive adhesive satisfying the above physical properties, and the first pressure-sensitive adhesive layer 21 ) And the first retardation plate (11) made of acrylic resin on the surface in contact with the first pressure sensitive adhesive layer (21).

In addition, by having the first retardation plate 11 and the second retardation plate 12 as described above, it is possible to exhibit excellent viewing angle compensation performance in a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device .

The gel fraction of the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 21 is 55 to 90%, preferably 65 to 85%, particularly preferably 73 to 78% as described above. If the gel fraction is less than 55%, the durability of the resulting display panel is deteriorated. If the gel fraction is more than 90%, the display panel is liable to bend under a high temperature condition, and thermal unevenness tends to occur.

The gel fraction of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 is 80 to 100%, preferably 85 to 99%, and particularly preferably 90 to 97% as described above. If the gel fraction is less than 80%, the durability of the resulting display panel tends to deteriorate.

Here, the measurement method of the gel fraction of the pressure-sensitive adhesive is as shown in the following test example.

The storage elastic modulus G 'of the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 21 at 85 캜 is preferably 0.03 to 0.25 MPa, more preferably 0.06 to 0.15 MPa, 0.10 MPa. If the storage elastic modulus (G ') is less than 0.03 MPa, the durability of the resulting display panel is reduced. If the storage elastic modulus (G') is more than 0.25 MPa, the display panel is liable to bend under a high temperature condition.

The storage elastic modulus G 'of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 at 85 캜 is 0.15 to 3.00 MPa, preferably 0.20 to 1.00 MPa, and particularly preferably 0.25 to 3.00 MPa as described above. 0.50 MPa. If the storage elastic modulus G 'is less than 0.15 MPa, the adhesiveness of the second pressure-sensitive adhesive layer 22 becomes insufficient when the thickness of the second pressure-sensitive adhesive layer 22 is thinned. If the storage elastic modulus G' exceeds 3.00 MPa, The durability tends to deteriorate in any case.

Here, the measurement method of the storage elastic modulus (G ') of the pressure-sensitive adhesive is as shown in the following test examples.

Although not shown, in the first pressure-sensitive adhesive layer 21, on the side opposite to the side of the first retardation plate 11 (the lower side in Fig. 1), until the optical film 1A with the pressure-sensitive adhesive layer is used , And a release sheet may be laminated.

1. First retardation plate

The first retardation plate 11 may be composed of a single layer exhibiting a retardation or a plurality of layers including a retardation layer. The surface of the first retardation plate 11 which is in contact with the first pressure-sensitive adhesive layer 21 is made of acrylic resin. The use of the acrylic resin in the place of the first retardation plate 11 makes it possible to make the thickness of the first retardation plate 11 thin without hindering the predetermined optical performance. When the first retardation plate 11 is a single layer, the first retardation plate 11 is made of a single layer of acrylic resin. In the case where the first retardation plate 11 is composed of a plurality of layers, it is preferable that the outermost layer in contact with the first pressure-sensitive adhesive layer 21 is made of an acrylic resin layer formed through extrusion molding. Such an acryl-based resin and a conventionally-known pressure-sensitive adhesive layer have low adhesion and low durability. However, the first pressure-sensitive adhesive layer 21 according to the present embodiment has high adhesive strength and excellent stress relaxation property to an acrylic resin. Therefore, it is excellent in durability even under a high temperature condition, a wet heat condition and a heat shock. The " acrylic resin layer formed through extrusion molding " also includes an acrylic resin layer obtained by extrusion molding and stretching treatment.

It is preferable that the first retardation film 11 in this embodiment has at least an acrylic resin layer and a phase difference developing layer. In particular, as shown in Fig. 2, the phase difference developing layer 112, The first acrylic resin layer 111 laminated on one surface (the lower surface in Fig. 2) of the expression layer 112 and the first acrylic resin layer 111 laminated on the other surface (the upper surface in Fig. 2) And a second acrylic resin layer 113 laminated thereon. The retardation developing layer 112 is preferably made of a styrenic resin from the viewpoint that the intrinsic birefringence is negative and thinning is easy. As described above, the pressure-sensitive adhesive layer (1) having the first retardation plate (11) comprising the first acrylic resin layer (111), the retardation developing layer (112) composed of the styrene resin and the second acrylic resin layer The adhesion optical film 1A is excellent in the viewing angle compensation performance of a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device. In addition, since the retardation developing layer 112 is protected by the first acrylic resin layer 111 and the second acrylic resin layer 113 present on both sides thereof, the pressure-sensitive adhesive layer- The mechanical strength and the chemical resistance are excellent without deteriorating the performance of the substrate 112.

When the first acrylic resin layer 111 is in contact with the first pressure-sensitive adhesive layer 21 in the first retardation film 11, the first acrylic resin layer 111 is bonded to the first retardation film 11, As shown in Fig. Therefore, the optical film (1A) with the pressure-sensitive adhesive layer is excellent in durability under a high-temperature condition, a heat-shock condition, and the like.

It is preferable that the first retardation plate 11 is provided with in-plane retardation by stretching. As a result, the viewing angle compensation performance is more excellent.

The styrene resin constituting the phase difference-generating layer 112 may be a homopolymer of styrene or a derivative thereof, or may be a binary or a copolymer of styrene or a derivative thereof and another copolymerizable monomer. The styrene derivative is a compound in which other groups are bonded to styrene, and examples thereof include alkyls such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, Substituted styrenes such as styrene, hydroxystyrene, tert-butoxystyrene, vinylbenzoic acid, o-chlorostyrene, p-chlorostyrene, etc. in which a benzene nucleus of styrene has a hydroxyl group, an alkoxy group, a carboxyl group, .

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

The styrene resin constituting the phase difference developing layer 112 is preferably a copolymer of styrene or a styrene derivative and at least one monomer selected from acrylonitrile, maleic anhydride, methyl methacrylate and butadiene.

As the styrene resin constituting the phase difference-generating layer 112, a styrene resin having heat resistance is preferable. The glass transition temperature (Tg) of the styrenic resin is generally 100 ° C or higher, but it is preferably a styrenic resin having a glass transition temperature (Tg) of 120 ° C or higher.

The thickness of the phase difference-generating layer 112 is preferably 10 to 100 mu m. When the thickness of the retardation developing layer 112 is 10 占 퐉 or more, a sufficient retardation value is developed by stretching. On the other hand, when the thickness of the retardation developing layer 112 is 100 m or less, the impact strength is high, and the change in retardation due to external stress is small, and when applied to a liquid crystal display device, heat unevenness hardly occurs.

The first acrylic resin layer 111 and the second acrylic resin layer 113 are preferably made of a (meth) acrylic resin composition in which rubber particles are blended with a (meth) acrylic resin. By mixing the rubber particles, the impact resistance of the acrylic resin layer can be increased.

Examples of the (meth) acrylic resin include a homopolymer of an alkyl methacrylate or an alkyl acrylate, a copolymer of an alkyl methacrylate and an alkyl acrylate, and the like. Examples of the methacrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate and propyl acrylate. As such (meth) acrylic resins, those commercially available as general-purpose (meth) acrylic resins can be used. Incidentally, the (meth) acrylic resin includes what is called an impact (meth) acrylic resin, and also what is called a high heat resistant (meth) acrylic resin having a glutaric anhydride structure or a lactone ring structure in the main chain.

The rubber particles to be blended in the (meth) acrylic resin are preferably acrylic ones. The acrylic rubber particles are rubber-elastic particles obtained by polymerizing an acrylic acid alkyl ester such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer.

The rubber particles may be a homogeneous material having rubber elasticity, or a multilayer structure having at least one rubber elastic layer. Examples of the acrylic rubber particles having a multilayer structure include those having rubber elastic particles as the nucleus and covering the periphery thereof with a hard methacrylic acid alkyl ester polymer and hard acrylic methacrylic acid alkyl ester polymers as nuclei And the periphery thereof is covered with an acrylic polymer having rubber elasticity as described above and that the periphery of the hard core is covered with an acrylic polymer having rubber elasticity and the periphery thereof is covered with a hard methacrylic acid alkyl ester polymer And the like.

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

The content of the rubber particles in the (meth) acrylic resin composition constituting the first acrylic resin layer 111 and the second acrylic resin layer 113 is preferably 5 to 50 parts by mass per 100 parts by mass of the (meth) .

As the (meth) acrylic resin composition constituting the first acrylic resin layer 111 and the second acrylic resin layer 113, those commercially available in a mixed state of a (meth) acrylic resin and an acrylic rubber particle can be used . Examples of commercially available products of (meth) acrylic resin ((meth) acrylic resin composition) in which acrylic rubber particles are blended are "HT55X" and "Technoloy S001" sold by Sumitomo Chemical Co., .

(Meth) acryl-based resin composition having a glass transition temperature (Tg) of 160 ° C or lower, but a glass transition temperature (Tg) of 120 ° C or lower is preferable, An acrylic resin composition is preferable. That is, it is preferable that the glass transition temperature (Tg) of the phase difference developing layer 112 does not overlap with the glass transition temperature (Tg) of the first acrylic resin layer 111 and the second acrylic resin layer 113, It is preferable that the layer 112 has a higher glass transition temperature (Tg) than the first acrylic resin layer 111 and the second acrylic resin layer 113.

The materials of the first acrylic resin layer 111 and the second acrylic resin layer 113 may be the same or different.

It is preferable that the thicknesses of the first acrylic resin layer 111 and the second acrylic resin layer 113 are respectively 10 to 100 占 퐉. If the thickness is 10 mu m or more, the film can be easily formed. If the thickness is 100 mu m or less, the retardation of the first acrylic resin layer 111 and the second acrylic resin layer 113 can be ignored. The thickness of the first acrylic resin layer 111 and the thickness of the second acrylic resin layer 113 are preferably substantially the same.

The surface of the first retardation plate 11 on the side of the second pressure sensitive adhesive layer 22 may be subjected to surface treatment such as corona treatment.

In order to manufacture the first retardation film 11, for example, a styrene resin and a (meth) acrylic resin composition containing rubber particles are co-extruded and then stretched. The stretching can be performed by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, or sequential biaxial stretching, and stretching can be performed to obtain a desired retardation value. (Phase difference developing layer 112, first acrylic resin layer 111 and second acrylic resin layer 113) are formed by heat lamination by heat lamination in addition to the above method, The sieve may be stretched.

The total thickness of the first retardation film 11 after stretching is preferably 5 to 100 占 퐉, more preferably 10 to 50 占 퐉, from the viewpoint of meeting the requirement for thinning in mobile applications while maintaining sufficient performance And particularly preferably 15 to 30 탆.

2. First adhesive layer

The first pressure sensitive adhesive layer 21 may be composed of a pressure sensitive adhesive having the above physical properties, but is preferably composed of an acrylic pressure sensitive adhesive. Particularly preferably, the monomer (a1) containing an alicyclic structure, (A) obtained from a pressure-sensitive adhesive composition containing a crosslinking agent (hereinafter sometimes referred to as a " pressure-sensitive adhesive composition (P) ") containing a (meth) acrylic acid ester copolymer . In the present specification, (meth) acrylic acid ester means both of acrylic acid ester and methacrylic acid ester. The same is true of other similar terms.

By containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2), the resulting pressure-sensitive adhesive can have both appropriate cohesive force and stress relaxation property and also has high adhesiveness to the optical film or transparent conductive film Therefore, when used in a display panel, excellent durability, deflection suppression, and heat resistance non-uniformity can be exhibited.

(1) (meth) acrylic acid ester copolymer (A)

(Meth) acrylic acid ester copolymer (A) is preferably a copolymer containing a hydroxyl group-containing monomer (a3) in addition to the above-mentioned alicyclic structure-containing monomer (a1) and an aromatic ring- (Meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group is particularly preferable. In addition, other monomers may be contained as desired.

The hydroxyl value of the (meth) acrylic acid ester copolymer (A) is preferably 5 to 20 mg KOH / g, more preferably 8 to 18 mg KOH / g, further preferably 10 to 16 mg KOH / g desirable. When the hydroxyl group value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or more, the crosslinking point can be ensured and the cohesive force can be maintained high, and the storage elastic modulus and gel fraction of the resulting pressure sensitive adhesive can be designed within the above- easy. When the hydroxyl group value of the (meth) acrylic acid ester copolymer (A) is 20 mgKOH / g or less, excessive cross-linking points are prevented to obtain a flexible pressure sensitive adhesive, and the storage elastic modulus and gel fraction are set to the above- It is easy to design with a range.

The acid value of the (meth) acrylic acid ester copolymer (A) is preferably 5 mgKOH / g or less, more preferably 2 mgKOH / g or less, and further preferably 1 mgKOH / g or less. When the acid value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or less, the object to which the pressure-sensitive adhesive is applied is a transparent conductive film such as tin-doped indium oxide Even in the case of a metal film or the like, these problems due to acid can be suppressed. In particular, when the object to be pasted is a transparent conductive film, it is possible to inhibit the transparent conductive film from being corroded or changing the resistance value of the transparent conductive film. The lower limit of the acid value of the (meth) acrylic acid ester copolymer (A) is preferably as small as possible, and is particularly preferably 0 mgKOH / g.

Here, the hydroxyl value and the acid value in the present specification are basically theoretical values derived from the mixing ratio of the (meth) acrylic acid ester copolymer (A), and when the theoretical value can not be derived, the hydroxyl value and the acid value are based on JIS K0070 .

(Meth) acrylic acid ester copolymer (A) can exhibit favorable tackiness by containing a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (Meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl Myristyl, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among them, (meth) acrylic esters having an alkyl group of 1 to 8 carbon atoms are preferable, n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is more preferable from the viewpoint of further improving the stickiness. N-butyl (meth) acrylate is particularly preferable from the viewpoint that the glass transition temperature (Tg) of the (meth) acrylic acid ester copolymer (A) can be increased. These may be used alone or in combination of two or more.

(Meth) acrylic acid ester copolymer (A) preferably contains 40 to 97.5 mass% of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer, particularly preferably 55 to 94 By mass, more preferably 65 to 83% by mass. When the (meth) acrylic acid alkyl ester is contained in an amount of 40 mass% or more, the (meth) acrylic acid ester copolymer (A) can be given favorable tackiness. In addition, by making the (meth) acrylic acid alkyl ester 97.5% by mass or less, a desired amount of other monomer components can be introduced into the (meth) acrylic acid ester copolymer (A).

The carbon ring of the alicyclic structure in the alicyclic structure-containing monomer (a1) may have a saturated structure or may have an unsaturated bond in a part thereof. The alicyclic structure may be a monocyclic alicyclic structure or a multicyclic alicyclic structure such as two or three rings. The glass transition temperature (Tg) of the (meth) acrylic ester copolymer (A) to be obtained is adjusted to be a value obtained by appropriately adjusting the distance between the obtained (meth) acrylic ester copolymer (A) From the viewpoint of improving the adhesion with an acrylic resin by raising the alicyclic structure, it is preferable that the alicyclic structure is a polycyclic alicyclic structure (polycyclic structure). In consideration of compatibility of the (meth) acrylic acid ester copolymer (A) with other components, it is particularly preferable that the above-mentioned polycyclic structure is 2 to 4 rings. From the viewpoint of imparting stress relaxation properties and increasing the glass transition temperature (Tg) of the resulting (meth) acrylic acid ester copolymer (A) as described above, the number of carbon atoms of the alicyclic structure And when the plurality of rings are independently present, the total number of carbon atoms is preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the carbon number of the alicyclic structure is not particularly limited, but from the viewpoint of compatibility as described above, it is preferably 15 or less, and particularly preferably 10 or less.

Examples of the alicyclic structure include a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isobornyl skeleton, a cycloalkane skeleton (a cycloheptane skeleton, a cyclooctane skeleton, a cyclononane skeleton, a cyclodecane skeleton, Cyclopentene skeleton, cyclohexene skeleton, cyclododecane skeleton, etc.), cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubhenain skeleton, (10 carbon atoms in the alicyclic structure), an adamantane skeleton (the number of carbon atoms in the alicyclic structure: 10), or a dicyclopentadiene skeleton An isobornyl skeleton (the number of carbon atoms in the alicyclic structure: 7), and particularly preferably an isobornyl skeleton.

As the alicyclic structure-containing monomer (a1), a (meth) acrylic acid ester monomer containing the above skeleton is preferable. Specific examples thereof include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (Meth) acrylate dicyclopentenyl acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and the like. Among them, Dicyclopentanyl acrylate, adamantyl (meth) acrylate or isobornyl (meth) acrylate is preferable, and isobornyl (meth) acrylate is particularly preferable. These may be used singly or in combination of two or more kinds.

(Meth) acrylic acid ester copolymer (A) is preferably a monomer having an alicyclic structure (a1) as a monomer unit constituting the polymer from the viewpoint of exhibiting excellent durability, flexural inhibition property and heat resistance non- By mass to 20% by mass. In addition to the above viewpoints, it is more preferable that the obtained pressure-sensitive adhesive contains from 2 to 15 mass%, particularly preferably from 3 to 9 mass%, of the alicyclic structure-containing monomer (a1) from the viewpoint of exhibiting excellent reworkability Particularly preferred.

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

Examples of the aromatic ring-containing monomer (a2) include phenyl (meth) acrylate, 2-phenylethyl (meth) acrylate, benzyl (meth) acrylate, naphthyl (meth) acrylate, phenoxyethyl (Meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified cresol (meth) acrylate, ethylene oxide (EO) modified nonylphenol (meth) acrylate, etc. Among them, 2-phenylethyl (meth) acrylate is preferable in terms of improving the cohesion. These may be used alone or in combination of two or more.

(Meth) acrylic acid ester copolymer (A) preferably contains 1 to 30 mass%, more preferably 3 to 25 mass%, of the aromatic ring-containing monomer (a2) as the monomer unit constituting the polymer By mass, more preferably from 12 to 22% by mass. When the content of the aromatic ring-containing monomer (a2) is within the above range, the resulting pressure-sensitive adhesive can exhibit excellent durability, flexural restraining property and heat resistance non-uniformity.

The (meth) acrylic acid ester copolymer (A) preferably contains the hydroxyl group-containing monomer (a3) as the monomer unit constituting the polymer. The hydroxyl groups show good reactivity with the crosslinking agent (B), and the (meth) acrylic acid ester copolymer (A) is crosslinked by the crosslinking agent (B) by the reaction thereof. With the crosslinking structure, the obtained pressure-sensitive adhesive easily satisfies the storage elastic modulus and the gel fraction.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) (Meth) acrylic acid hydroxyalkyl esters such as butyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. Among them, in view of reactivity with the crosslinking agent 2-hydroxyethyl methacrylate or 4-hydroxybutyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is particularly preferable. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) preferably contains 0.5 to 10 mass%, more preferably 1 to 5 mass%, of the hydroxyl group-containing monomer (a3) as the monomer unit constituting the polymer By mass, more preferably from 2 to 4% by mass. When the content of the hydroxyl group-containing monomer (a3) falls within the above range, the hydroxyl value of the (meth) acrylic acid ester copolymer (A) tends to fall within the above-mentioned range and the above storage elastic modulus and gel fraction can be easily satisfied .

(Meth) acrylic acid ester copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer in order to keep the acid value within the above-mentioned range, and even if it contains 0.5 mass% By mass, and particularly preferably 0.1% by mass or less.

The (meth) acrylic acid ester copolymer (A) may contain a monomer other than the monomer described above as a monomer unit constituting the polymer. The other monomer is preferably a monomer which does not contain a functional group reactive with the crosslinking agent (B) so as not to interfere with the reaction between the hydroxyl group of the hydroxyl group-containing monomer (a3) and the crosslinking agent (B).

Examples of such other monomers include non-crosslinkable acrylamides such as (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, acrylamide and methacrylamide, (Meth) acrylate, N, N-dimethylaminoethyl, (meth) acrylic acid N, N-dimethylaminopropyl and the like. These may be used alone or in combination of two or more.

The polymerization of the (meth) acrylic acid ester copolymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably from 1.3 to 3 million, more preferably from 1.5 to 2.5 million, and further preferably from 1.6 to 1.9 million. When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is 1.3 million or more, the storage elastic modulus and the gel fraction of the obtained pressure sensitive adhesive can be easily designed to be higher than the lower limit described above, and durability can be satisfactorily secured. When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is 3,000,000 or less, the storage elastic modulus and the gel fraction of the obtained pressure sensitive adhesive can be easily designed to be equal to or less than the upper limit value described above, It is possible to effectively exhibit inhibitory properties and heat non-uniformity.

Here, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC).

In the sticky composition (P), the (meth) acrylic acid ester copolymer (A) may be used singly or in combination of two or more kinds. The adhesive composition (P) may further contain a (meth) acrylic acid ester polymer containing no alicyclic structure-containing monomer (a1) or an aromatic ring-containing monomer (a2) as a constituent monomer unit.

(2) Crosslinking agent (B)

The crosslinking agent (B) may be any as long as it reacts with the functional group of the (meth) acrylic acid ester copolymer (A), and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, Based crosslinking agent, an aldehyde-based crosslinking agent, an oxazoline-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelating-type crosslinking agent, a metal salt-based crosslinking agent, and an ammonium salt-based crosslinking agent.

Containing monomer (a3) as the monomer unit constituting the polymer, the (meth) acrylic acid ester copolymer (A) is preferably an isocyanate-based crosslinking agent (a3) having excellent reactivity with the hydroxyl group derived from the hydroxyl group- Is preferably used. The crosslinking agent (B) may be used singly or in combination of two or more.

The isocyanate crosslinking agent includes at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane Alicyclic polyisocyanates such as diisocyanate and the like, and reaction products thereof with low-molecular active hydrogen-containing compounds such as burette, isocyanurate, and further ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, (Sometimes collectively referred to as a " modified body "), and the like. Among them, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified product thereof is preferable from the viewpoint of the durability of the resulting pressure-sensitive adhesive. An aromatic compound (preferably an alkylene chain, And particularly preferably an alkylene chain of 1 to 4 carbon atoms, may be particularly preferably used), or an isocyanate group-modified isocyanate or a modified product thereof. More specifically, xylylenediisocyanate or a modified product thereof is more preferable, and trimethylolpropane-modified xylylene diisocyanate is most preferable. The isocyanate crosslinking agent may be used singly or in combination of two or more.

The content of the crosslinking agent (B) in the adhesive composition (P) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester copolymer (A) , Further preferably 0.1 to 0.4 parts by mass. When the content of the crosslinking agent (B) is in the above range, it becomes easy to control the storage elastic modulus and the gel fraction of the obtained pressure sensitive adhesive within the above-mentioned range.

(3) Silane coupling agent (C)

The sticky composition (P) preferably contains a silane coupling agent (C) in addition to the (meth) acrylic acid ester copolymer (A) and the crosslinking agent (B), and from the viewpoint of imparting excellent durability to the obtained pressure- Containing silane coupling agent (C1) and / or a mercapto group-containing silane coupling agent (C2), and further preferably an epoxy group-containing silane coupling agent (C1) and a mercapto group-containing silane coupling agent It is preferable to contain both of them.

The epoxy group-containing silane coupling agent (C1) is preferably an organosilicon compound having at least one epoxy group (an organic group containing an epoxy group) in the molecule and at least one alkoxysilyl group, and is excellent in compatibility with a pressure- For example, substantially transparent.

Specific examples of the epoxy group-containing silane coupling agent (C1) include 3-glycidoxypropyltrialkoxysilane such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane, 3- 3-glycidoxypropylalkyldialkoxysilane such as propylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, methyltri (glycidyl) silane, 2- (3,4-epoxycyclohexyl 2- (3,4-epoxycyclohexyl) ethyltrialkoxysilane such as ethyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane. Among them, from the viewpoint of further improving durability, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane is preferable, and 3-glycidoxypropyltrimethoxysilane is particularly preferable. These may be used singly or in combination of two or more kinds.

The mercapto group-containing silane coupling agent (C2) is preferably an organosilicon compound having at least one mercapto group (an organic group containing a mercapto group) and at least one alkoxysilyl group in the molecule, and has compatibility with a pressure- And it is also preferable that it has optical transparency, for example, substantially transparent.

Specific examples of the mercapto group-containing silane coupling agent (C2) include mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyldimethoxymethylsilane, Containing low molecular weight silane coupling agent; A mercapto group-containing silane compound such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane, and a mercapto group-containing silane compound such as methyltriethoxysilane, ethyltriethoxysilane Containing oligomer-type silane coupling agents such as co-condensates of alkyl group-containing silane compounds such as methyltrimethoxysilane and ethyltrimethoxysilane. Among them, a mercapto group-containing oligomer-type silane coupling agent is preferable from the standpoint of achieving both durability and reworkability, and a cocondensation product of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable. - cocondensates of mercaptopropyltrimethoxysilane and methyltriethoxysilane are preferred. These may be used singly or in combination of two or more kinds.

Examples of the silane coupling agent (C) include, in addition to the epoxy group-containing silane coupling agent (C1) and the mercapto group-containing silane coupling agent (C2), an acryloyl silane coupling agent, , A carboxyl group silane coupling agent, an amino silane coupling agent, an amide silane coupling agent, and an isocyanate silane coupling agent may be used in combination.

The total content of the silane coupling agent (C) in the viscous composition (P) is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester copolymer (A) , More preferably from 0.2 to 1 part by mass.

The content of the epoxy group-containing silane coupling agent (C1) in the adhesive composition (P) is preferably 0.005 to 2.5 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester copolymer (A) 1 part by mass, more preferably 0.1 to 0.5 part by mass. On the other hand, the content of the mercapto group-containing silane coupling agent (C2) in the adhesive composition (P) is preferably 0.005 to 2.5 parts by mass relative to 100 parts by mass of the (meth) acrylic acid ester copolymer (A) It is preferably 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass.

(4) Antistatic agent (D)

The sticky composition (P) preferably further contains an antistatic agent (D). Since the optical film (the first retardation film 11) or the release sheet laminated on the first pressure sensitive adhesive layer 21 is usually composed of a plastic material, the electrical insulation is high and static electricity is generated when the release sheet is peeled off It is easy to occur. When the optical film thus formed remains in the state of remaining static electricity, when the liquid crystal cell is stuck to the liquid crystal cell, the orientation of the liquid crystal molecules may be confused, and the presence of static electricity causes problems such as sucking dust and dirt . Thus, when the adhesive composition (P) contains the antistatic agent (D), the resulting pressure-sensitive adhesive (first pressure-sensitive adhesive layer (21)) exhibits antistatic properties and can solve the above problems.

The antistatic agent (D) may be any one capable of imparting antistatic properties to the resulting pressure-sensitive adhesive. Examples of the antistatic agent (D) include an ionic compound and a nonionic compound. Among them, an ionic compound is preferable. The ionic compound may be a liquid at room temperature or a solid, but is preferably a solid at room temperature from the viewpoint of easily developing stable antistatic property even when exposed to the durability conditions. Herein, the ionic compound in the present specification refers to a compound in which cations and anions are mainly bonded by an electrostatic attractive force.

As the ionic compound, a nitrogen-containing onium salt, a sulfur onium salt, a zinc onium salt, an alkali metal salt and an alkaline earth metal salt are preferable, and a nitrogen-containing onium salt is particularly preferable from the viewpoint of excellent durability of the obtained pressure- The nitrogen-containing onium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a counter anion, and is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric anion , And more preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion as a solid at room temperature. According to an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric anion as a solid at room temperature, it is possible to achieve both antistatic property and durability.

The nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation is preferably a pyridine ring, a pyrimidine ring, an imidazole ring, a triazole ring or an indole ring. Of these, a pyridine ring is preferable. The halogen of the halogenated phosphoric anion is preferably fluorine, chlorine, bromine or the like, and fluorine is particularly preferable.

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, 4-methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N -Dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4-methylpyridinium hexafluorophosphate, and N-hexadecyl-4-methylpyridinium hexafluorophosphate. Among them, from the viewpoint of compatibility with the (meth) acrylic acid ester copolymer (A), preferred are N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, -4-methylpyridinium hexafluorophosphate are preferable. The above antistatic agents (D) may be used alone or in combination of two or more.

The content of the antistatic agent (D) in the viscous composition (P) is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester copolymer (A) And further preferably 1 to 5 parts by mass. When the content of the antistatic agent (D) is within the above range, the antistatic property can be effectively exhibited and the deterioration of physical properties such as optical properties and durability can be prevented.

(5) Various additives

The pressure-sensitive adhesive composition (P) may contain various additives conventionally used in acrylic pressure-sensitive adhesives, such as a dispersant (e.g., an alkylene glycol dialkyl ether), a tackifier, an antioxidant, , A softening agent, a filler, a refractive index adjusting agent, and the like. Further, the adhesive composition (P) represents a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or remains in the pressure-sensitive adhesive layer, and components such as a polymerization solvent and a diluting solvent , And is not included in the sticky composition (P).

(6) Production method of sticky composition

The sticky composition (P) is obtained by preparing a (meth) acrylic acid ester copolymer (A) and reacting the obtained (meth) acrylic acid ester copolymer (A), the crosslinking agent (B) and the silane coupling agent , An antistatic agent (D), an additive, and the like.

The (meth) acrylic acid ester copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a conventional radical polymerization method. The polymerization of the (meth) acrylic acid ester copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as desired. As the polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like may be used.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more types may be used in combination. Examples of the azo compound include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane- (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy valeronitrile), dimethyl 2,2 ' Azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile) -Azobis [2- (2-imidazolin-2-yl) propane].

Examples of the organic peroxide include organic peroxides such as benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) Carbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

In addition, the weight average molecular weight of the resulting polymer can be controlled by blending a chain transfer agent such as 2-mercaptoethanol in the polymerization step.

(B) and a silane coupling agent (C), an antistatic agent (D), an antistatic agent (C), and an antistatic agent (C) are added to a solution of the (meth) acrylic acid ester copolymer (P) (coating solution) diluted with a solvent is obtained by adding an additive, a diluting solvent and the like and sufficiently mixing them.

Examples of the diluting agent for diluting the adhesive composition (P) into a coating solution include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated compounds such as methylene chloride and ethylene chloride Alcohols such as methanol, ethanol, propanol, butanol and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone; Ester solvents, cellosolve solvents such as ethyl cellosolve, and the like.

The concentration and viscosity of the coating solution thus prepared are not particularly limited and may be appropriately selected according to the circumstances. For example, it is diluted such that the concentration of the sticky composition (P) is 10 to 40% by mass. Further, in the case of obtaining the coating solution, it is not necessary to add a diluting solvent or the like, and a diluting solvent may not be added if the viscosity of the adhesive composition (P) is such that it can be coated. In this case, the adhesive composition (P) becomes a coating solution containing the polymerization solvent of the (meth) acrylic acid ester copolymer (A) as it is as a diluting solvent.

(7) Adhesive

The pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 21 in the present embodiment is obtained from the pressure-sensitive adhesive composition (P) described above, specifically, the pressure-sensitive adhesive composition (P) is crosslinked. The crosslinking of the viscous composition (P) can be carried out by a heat treatment. This heat treatment may also be used in the drying treatment for volatilizing the diluting solvent or the like of the adhesive composition (P).

When the heat treatment is carried out, the heating temperature is preferably 50 to 150 占 폚, particularly preferably 70 to 120 占 폚. The heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be formed at room temperature (for example, 23 DEG C, 50% RH). When the curing period is necessary, after the curing period, if the curing period is not necessary, a pressure-sensitive adhesive layer having a predetermined physical property is formed after the heat treatment is finished.

The (meth) acrylic acid ester copolymer (A) is crosslinked by the crosslinking agent (B) by the above heat treatment (and curing) to form a three-dimensional mesh structure. The degree of cross-linking of the pressure-sensitive adhesive obtained by crosslinking in this way, that is, the gel fraction is in the range described above.

(8) Physical properties of the first pressure-sensitive adhesive layer

The thickness of the first pressure-sensitive adhesive layer 21 is preferably 5 to 100 占 퐉, more preferably 10 to 60 占 퐉, particularly preferably 10 to 50 占 퐉, and still more preferably 15 to 30 占 퐉. When the thickness of the first pressure sensitive adhesive layer 21 is within the above range, the effect based on the gel fraction and the storage elastic modulus of the pressure sensitive adhesive constituting the first pressure sensitive adhesive layer 21, that is, the excellent durability, Is effectively exercised.

The haze value (value measured according to JIS K7136: 2000) of the first pressure-sensitive adhesive layer 21 is preferably 2% or less, more preferably 1% or less. When the haze value is 2% or less, the transparency is extremely high and is preferable for optical use.

3. Second pressure-sensitive adhesive layer

The second pressure sensitive adhesive layer 22 may be composed of a pressure sensitive adhesive having the above physical properties and may be a curable pressure sensitive adhesive or an uncurable pressure sensitive adhesive. However, in order to keep the storage elastic modulus and gel fraction within the above range, It is preferable to use an adhesive.

The active energy ray-curable pressure-sensitive adhesive may contain a polymer having an active energy ray curable property as a main component or a mixture of a polymer having no active energy ray curable property and a mixture of an active energy ray curable multifunctional monomer and / It is acceptable. A mixture of a polymer having active energy ray curability and a polymer having no active energy ray curability may be a mixture of a polymer having active energy ray curability and an active energy ray curable multifunctional monomer and / It may be a mixture of species.

Above all, from the viewpoint of easily obtaining a pressure-sensitive adhesive exhibiting cohesive strength while maintaining adhesiveness, it is preferable that a main component is a mixture of a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer and / In particular, it is preferable to use as a main component a mixture of a polymer having no active energy ray curability and an active energy ray-curable multifunctional monomer.

(Meth) acrylic acid ester polymer (hereinafter sometimes referred to as "(meth) acrylic acid ester polymer (X)") having no active energy ray-curable group is preferable as the polymer having no active energy ray curability. The (meth) acrylic acid ester polymer (X) preferably contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer constituting the polymer. As a result, the obtained pressure-sensitive adhesive can exhibit desirable tackiness. The (meth) acrylic acid ester polymer (X) is obtained by polymerizing a (meth) acrylic acid alkyl ester having an alkyl group of 1 to 20 carbon atoms, a monomer having a reactive functional group (a reactive functional group containing monomer) Is particularly preferable. (Meth) acrylic acid ester polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, it is possible to improve adhesion to a glass surface of a liquid crystal cell or the like, To form a crosslinked structure.

Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (Meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl Myristyl, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among them, (meth) acrylic esters having an alkyl group of 1 to 8 carbon atoms are preferable, and n-butyl (meth) acrylate is particularly preferable from the viewpoint of further improving the tackiness. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (X) preferably contains 50 to 99 mass% of a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer, By mass, more preferably from 70 to 98% by mass.

Examples of the reactive functional group-containing monomer include a monomer having a hydroxyl group in the molecule (a hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (a carboxyl group-containing monomer), a monomer having an amino group in the molecule (an amino group-containing monomer) . These reactive functional group-containing monomers may be used singly or in combination of two or more.

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

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. Among them, acrylic acid is preferable in view of the reactivity of the carboxyl group in the resulting (meth) acrylic acid ester polymer (X) with the crosslinking agent (Z) and the copolymerization with other monomers. These may be used alone or in combination of two or more.

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

The (meth) acrylic acid ester polymer (X) preferably contains 1 to 25 mass%, more preferably 1 to 20 mass%, of the monomer having a reactive functional group as the monomer unit constituting the polymer, It is preferably contained in an amount of 2 to 5% by mass.

The polymerization of the (meth) acrylic acid ester polymer (X) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylic acid ester polymer (X) is preferably from 300,000 to 3,000,000, particularly preferably from 1,000,000 to 2,500,000, and more preferably from 1,600,000 to 2,200,000.

The (meth) acrylic acid ester polymer (X) may be used singly or in combination of two or more kinds.

As the active energy ray-curable multifunctional monomer, a multifunctional acrylate monomer having a molecular weight of 1,000 or less, which is excellent in compatibility with the (meth) acrylic acid ester polymer (X) and the like, is preferable.

Examples of the polyfunctional acrylate monomer having a molecular weight of 1000 or less include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone denatured (meth) acrylate, hydroxypivalic acid neopentyl glycol di Bifunctional types such as dicyclopentenyl (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (acryloxyethyl) isocyanurate and allyl cyclohexyldi (meth) acrylate; (Meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol propane Trifunctional types such as tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, and epsilon -caprolactone modified tris (2- (meth) acryloxyethyl) isocyanurate; Tetrafunctional types such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; Pentafunctional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And hexafunctional types such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate. These may be used singly or in combination of two or more kinds.

The content of the active energy ray-curable compound (Y) is preferably 1 to 50 parts by mass, particularly preferably 5 to 30 parts by mass, more preferably 10 to 30 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester polymer (X) 20 parts by mass.

The active energy ray-curable pressure-sensitive adhesive preferably contains a cross-linking agent (Z). When the pressure-sensitive adhesive contains the (meth) acrylic acid ester polymer (X) containing the reactive functional group-containing monomer as the monomer unit constituting the polymer and the crosslinking agent (Z), the crosslinking agent (Z) (Meth) acrylic ester polymer (X) is reacted with the reactive functional group of the reactive functional group-containing monomer constituting the (meth) acrylic acid ester polymer (X). Thereby, a structure in which the (meth) acrylic acid ester polymer (X) is crosslinked by the crosslinking agent (Z) is formed, the cohesive force of the obtained pressure sensitive adhesive is improved and the obtained pressure sensitive adhesive easily satisfies the storage elastic modulus and the gel fraction do.

The crosslinking agent (Z) is not particularly limited as long as it can react with the reactive functional group possessed by the (meth) acrylic acid ester polymer (X), and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, Based crosslinking agent, an aldehyde-based crosslinking agent, an oxazoline-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelating-type crosslinking agent, a metal salt-based crosslinking agent, and an ammonium salt-based crosslinking agent. As the isocyanate crosslinking agent, the same crosslinking agent (B) as the above-mentioned crosslinking agent (B) can be used. The crosslinking agent (Z) may be used singly or in combination of two or more kinds.

The content of the crosslinking agent (Z) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, further preferably 0.1 to 1 part by mass relative to 100 parts by mass of the (meth) acrylic acid ester polymer (X) desirable.

The active energy ray-curable pressure-sensitive adhesive may contain various additives such as a photopolymerization initiator, a silane coupling agent, a refractive index adjusting agent, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softening agent, You can.

When ultraviolet rays are used as an active energy ray for curing the active energy ray-curable pressure-sensitive adhesive, the active energy ray-curable pressure-sensitive adhesive preferably contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) -Propyl ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- tertiary- 2-methylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Acetophenone dimethyl ketal, p-dimethyl Methylbenzyl-phenyl] propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like can be given as examples of the aminobenzoic acid ester, oligo [2-hydroxy- have. These may be used alone or in combination of two or more.

The photopolymerization initiator is preferably used in an amount in the range of 0.1 to 20 parts by mass, particularly 1 to 12 parts by mass, based on 100 parts by mass of the active energy ray-curable compound (Y) in the above active energy ray-

The active energy ray-curable pressure-sensitive adhesive preferably contains a silane coupling agent from the viewpoint of improving the adhesion of the obtained pressure-sensitive adhesive to a film. As the silane coupling agent, an organosilicon compound having at least one alkoxysilyl group in the molecule is preferable because it has good compatibility with the adhesive component and has light transmittance.

Examples of such a silane coupling agent include, in addition to the aforementioned epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyl (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or a combination of at least one of these with methyltriethoxysilane, ethyltriethoxy And condensates of alkyl group-containing silicon compounds such as silane, methyltrimethoxysilane and ethyltrimethoxysilane. These may be used singly or in combination of two or more kinds.

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

The polymer having the active energy ray curability is preferably a (meth) acrylic acid ester (co) polymer to which a functional group having an active energy ray curable property (active energy radiation curable group) is introduced into the side chain.

The thickness of the second pressure-sensitive adhesive layer 22 is preferably 1 to 50 占 퐉, more preferably 1 to 20 占 퐉, and particularly preferably 2 to 7 占 퐉. When the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 has the above-described storage elastic modulus and gel fraction, even when the thickness of the second pressure-sensitive adhesive layer 22 is reduced to the above range, sufficient adhesiveness can be ensured. Further, by making the second pressure-sensitive adhesive layer 22 thin as described above, the loss of optical characteristics in the second pressure-sensitive adhesive layer 22 can be minimized.

4. Second retardation plate

The second retardation plate 12 is preferably made of an olefin resin. The olefin resin is a resin composed of a structural unit derived from an alicyclic olefin such as a chain type aliphatic olefin such as ethylene or propylene, or a norbornene or a substituent thereof (hereinafter collectively referred to as a norbornene monomer). The olefin resin may be a copolymer using two or more kinds of monomers.

Among them, a cyclic olefin resin which is a resin mainly containing a constituent unit derived from an alicyclic olefin is preferably used as the olefin resin. The second retardation plate 12 is made of the cyclic olefin resin, and the change in the optical characteristics of the second retardation plate 12 under the durability condition can be suppressed to a small degree.

Typical examples of the alicyclic olefin constituting the cyclic olefin-based resin include norbornene-based monomers and the like. Norbornene is a compound in which one carbon-carbon bond of a norbornane is a double bond and is named bicyclo [2,2,1] hept-2-ene according to the IUPAC nomenclature. Examples of the substituent of norbornene include 3-substituted, 4-substituted, and 4,5-di-substituted with the double bond position of the norbornene at the 1,2-position, and further, dicyclopentane Dienes and dimethano-octahydronaphthalenes can also be used as the monomers constituting the cyclic olefin-based resin.

The cyclic olefin resin may or may not have a norbornane ring in its constituent unit. Examples of the norbornene-based monomer forming the cyclic olefin-based resin having no norbornane ring in the constitutional unit include, for example, those which are five-membered ring by ring opening, typically norbornene, dicyclopentane Diene, 1- or 4-methylnorbornene, 4-phenylnorbornene, and the like. When the cyclic olefin resin is a copolymer, the arrangement of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer.

More specific examples of the cyclic olefin-based resin include, for example, a ring-opening polymer of a norbornene monomer, a ring-opening copolymer of a norbornene monomer and another monomer, a polymer denatured with a maleic acid moiety or a cyclopentadiene moiety Water, hydrogenated polymers or copolymers thereof, addition polymers of norbornene monomers, addition copolymers of norbornene monomers and other monomers, and the like. As the other monomer in the case of the copolymer,? -Olefins, cycloalkenes, nonconjugated dienes and the like can be given. The cyclic olefin-based resin may be a copolymer using one or more kinds of norbornene-based monomers and other alicyclic olefins.

Among these examples, as the cyclic olefin-based resin, a resin obtained by hydrogenating a ring-opening polymer using a norbornene-based monomer is preferably used. Such a cyclic olefin resin can be subjected to a stretching treatment to form a retarder. In addition to the stretching, a shrinkable film having a predetermined shrinkage ratio is laminated and subjected to heat shrinkage treatment, whereby the uniformity is high, It may be a retardation plate having a large retardation value.

Commercially available products of cyclic olefin resins using norbornene monomers include "Zeonex" and "Zeonoa" sold by Nippon Zeon Co., Ltd. and "Aton" sold by JSR Co., . Films of these cyclic olefin resins and stretched films thereof are also commercially available, and are commercially available from, for example, "Zeonoa Film" and JSR (trade name), all sold under the trade name of Nippon Zeon Co., And "Essina" sold by Sekisui Chemical Co., Ltd., and the like.

As the second retardation film 12, a film made of a mixed resin containing two or more kinds of olefin-based resins, or a film made of a mixed resin of an olefin-based resin and another thermoplastic resin may be used. For example, a mixed resin containing two or more kinds of olefin-based resins may be a mixture of the cyclic olefin-based resin and the chain-like aliphatic olefin-based resin as described above. When a mixed resin of an olefin resin and another thermoplastic resin is used, the other thermoplastic resin is appropriately selected in accordance with the purpose. Specific examples include polyvinyl chloride resins, cellulose resins, polystyrene resins, acrylonitrile / butadiene / styrene copolymer resins, acrylonitrile / styrene copolymer resins, (meth) acrylic resins, polyvinyl acetate resins, poly Based resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, Based resins, polyether sulfone-based resins, polyether ether ketone-based resins, polyarylate-based resins, liquid crystalline resins, polyamideimide-based resins, polyimide-based resins, and polytetrafluoroethylene- . The thermoplastic resin may be used singly or in combination of two or more kinds. The thermoplastic resin may be used after carrying out any suitable polymer denaturation. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, and stereoregularity impartation.

When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin is usually about 50 mass% or less and preferably about 40 mass% or less with respect to the total resin. By setting the content of other thermoplastic resin within this range, it is possible to obtain a phase difference plate having a small absolute value of the photoelastic coefficient, exhibiting good wavelength dispersion characteristics, and excellent durability, mechanical strength and transparency.

The olefin resin can be formed by a casting method from a solution, a melt extrusion method, or the like. In the case of film formation from two or more mixed resins, the film forming method is not particularly limited. For example, a film is produced by a casting method using a homogeneous solution obtained by mixing and mixing a resin component with a solvent in a predetermined ratio A method in which a resin component is melted and mixed at a predetermined ratio, and a film is produced by a melt extrusion method, and the like.

The film made of the olefin resin may contain other components such as a residual solvent, a stabilizer, a plasticizer, an antioxidant, an antistatic agent, and an ultraviolet absorber, if necessary. Further, a leveling agent may be contained in order to reduce surface roughness.

The surface of the second retardation plate 12 on the side of the second pressure sensitive adhesive layer 22 may be subjected to surface treatment such as corona treatment.

The second retardation film 12 has the following formulas (1) and (2), where refractive indexes in the in-plane slow axis direction, the in-plane fast axis direction and the thickness direction are denoted _by n _x , n _y and n _z , :

R _e = (n _x - n _y ) x d (1)

In-plane retardation value (R _e ) at a wavelength of 590 nm defined by the following formula (2): 30 to 150 nm,

Nz factor _{= (n x - n z)} / (n x - n y) (2)

Has an Nz coefficient of more than 1 and an index of refraction less than 2.

The second retardation film 12 having the refractive index anisotropy as described above can be obtained by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, or sequential biaxial stretching of a film made of the olefin resin, Various refractive index anisotropy can be obtained by appropriately selecting various temperatures such as a preheating temperature at the time of stretching, a stretching temperature, a heat setting temperature, a cooling temperature and the like in addition to appropriately adjusting the draw ratio and the stretching speed.

The thickness of the second retardation plate 12 is preferably in the range of 5 to 80 mu m, more preferably in the range of 10 to 80 mu m, and particularly preferably in the range of 10 to 30 mu m.

5. Manufacturing method of optical film with pressure-sensitive adhesive layer

A preferred example of the production method of the optical film (1A) with a pressure-sensitive adhesive layer will be described.

(1) Production of retardation plate laminate

First, a retardation film laminate composed of the first retardation plate 11, the second pressure-sensitive adhesive layer 22 and the second retardation plate 12 is produced. The production of the retardation plate laminate can be carried out by a conventional method.

For example, a coating film of a pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 is formed on the release surface of the release sheet. Specifically, the coating solution of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 is coated on the release surface of the release sheet and dried. The description of the release sheet will be described later.

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

When the drying is carried out by heat treatment, the heating temperature is preferably 50 to 150 ° C, more preferably 70 to 120 ° C. The heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes.

Next, a coating film of a pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer (22) on the release sheet is applied to the second retardation plate (12). Then, an active energy ray is irradiated onto the peeling sheet to cure the coating film of the pressure-sensitive adhesive, and the coating film is used as the second pressure-sensitive adhesive layer (22).

Here, the active energy ray refers to an energy having both energy in an electromagnetic wave or a charged particle beam, and specifically, ultraviolet rays, electron rays, and the like can be mentioned. Of the active energy rays, ultraviolet rays which are easy to handle are particularly preferable.

The irradiation with ultraviolet rays can be performed by a high-pressure mercury lamp, a metal halide lamp, a fusion H lamp, a xenon lamp, etc., and the irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW / cm ² . The amount of light, 50 ~ 10000 mJ / cm ² is not preferred, and more preferred 80 to a 5000 mJ / cm ² and is, particularly preferably 100 ~ 1000 mJ / cm ^2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation dose of the electron beam is preferably about 10 to 1000 krad.

Thereafter, the release sheet is peeled from the second pressure-sensitive adhesive layer 22 formed as described above, and the second acrylic resin layer 113 in the first retardation plate 11 is peeled off from the exposed second pressure- Side surface. Thus, a retardation film laminate (optical film) comprising the second retardation plate 12, the second pressure-sensitive adhesive layer 22 and the first retardation plate 11 laminated is obtained.

The total thickness of the retardation plate laminate is preferably 15 to 200 占 퐉, more preferably 25 to 150 占 퐉, and particularly preferably 30 to 65 占 퐉.

(2) Production of pressure-sensitive adhesive sheet for first pressure-sensitive adhesive layer

On the other hand, a pressure-sensitive adhesive sheet is produced by laminating a release sheet on one side or both sides of a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition (P). Here, as an example, a pressure-sensitive adhesive sheet comprising a release sheet laminated on both surfaces of a pressure-sensitive adhesive layer is to be produced.

Examples of the peeling sheet include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, (Meth) acrylate copolymer film, an ethylene / (meth) acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a polyimide film, a polyimide film, a polybutylene terephthalate film, A film, a fluororesin film, or the like is used. These crosslinked films are also used. Further, these laminated films may be used.

It is preferable that at least one surface of the release sheet (in particular, a release surface in contact with the pressure-sensitive adhesive layer) is subjected to a release treatment. As the releasing agent used in the peeling treatment, for example, an alkyd type, a silicone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type releasing agent may be mentioned. The peeling surface of the peeling sheet in the present specification means a surface having peeling property in the peeling sheet and includes both the surface subjected to the peeling treatment and the surface showing the peeling property without performing the peeling treatment.

When the release sheet is laminated on both surfaces of the pressure-sensitive adhesive layer, it is preferable that one of the release sheets is a heavy-duty release sheet having a large stripping force and the other release sheet is a light-

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

As an example of the method for producing the pressure-sensitive adhesive sheet, a coating solution of the adhesive composition (P) is applied to the release surface of the release sheet and heat treatment is performed to form a coating film. (The peeling surface is in contact with the coating film) or the substrate is laminated. When the curing period is not necessary, the coating film becomes the first pressure-sensitive adhesive layer 21 as it is, and when the curing period is required, it becomes the first pressure-sensitive adhesive layer 21 after the curing period elapses. The conditions of the heat treatment and curing are as described above.

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

(3) Production of optical film with pressure-sensitive adhesive layer

From the pressure-sensitive adhesive sheet thus obtained, one of the release sheets (the thin release type release sheet) is peeled off. Then, the first acrylic resin layer 111 of the first retardation film 11 in the retarder laminate is superimposed on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the retarder laminate are bonded. Thus, the above-mentioned pressure-sensitive adhesive layer-bearing optical film 1A (with a release sheet) is obtained.

Another example of the production method of the optical film (1A) with a pressure-sensitive adhesive layer is a method in which a solution (coating solution) containing the above-described sticky composition (P) is applied to the release surface of the release sheet, The first acrylic resin layer 111 of the first retardation plate 11 in the retardation plate laminate is superimposed on the coated film. When the curing period is required, the curing period is set so that the coating film becomes the first pressure-sensitive adhesive layer 21 when the curing period is unnecessary. Thus, the above-mentioned pressure-sensitive adhesive layer-bearing optical film 1A (with a release sheet) is obtained.

6. Properties of optical film with pressure-sensitive adhesive layer

The adhesive force of the optical film (1A) with a pressure-sensitive adhesive layer according to the present embodiment is preferably 0.5 to 20 N / 25 mm, more preferably 1 to 10 N / 25 mm, in terms of the adhesive force to the alkali-free glass. As a result, the optical film (1A) with a pressure-sensitive adhesive layer is more excellent in durability. Further, from the viewpoint of being excellent also in the reworkability, the adhesive force is preferably 2 to 7 N / 25 mm. The adhesive force referred to here is basically the adhesive force measured by the 180 deg. Peel method in accordance with JIS Z0237: 2009, wherein the measurement sample has a width of 25 mm and a length of 100 mm, and the sample to be measured is 0.5 MPa at 50 DEG C for 20 minutes, and then left at rest under the conditions of normal pressure, 23 DEG C, and 50% RH for 24 hours, and then measured at a peeling rate of 300 mm / min. When the adhesive force is within the above range, lifting, peeling, and the like can be effectively prevented when the liquid crystal cell is attached to the liquid crystal cell.

In the optical film (1A) with a pressure-sensitive adhesive layer according to the present embodiment, the adhesive strength (adhesive force after 14 days of application) after 14 days of storage under the conditions of 23 DEG C and 50% RH from the attachment to the adherend, It is preferably 1 to 20 N / 25 mm, more preferably 3 to 9 N / 25 mm. As described above, the pressure-sensitive adhesive layer-attached optical film 1A according to the present embodiment is excellent in the lithheet workability and can be easily reattached even after it is attached to the liquid crystal cell.

In the optical film (1A) with a pressure-sensitive adhesive layer according to the present embodiment, the adhesive force (adhesive force after 2 days at 50 占 폚) after standing for two days under the condition of 50 占 폚 and 50% RH from the adherend to the adherend From the viewpoint of durability, it is preferably 1 to 20 N / 25 mm, and more preferably 6 to 12 N / 25 mm in view of the reworkability.

The surface resistivity of the first pressure-sensitive adhesive layer 21 in the pressure-sensitive adhesive layer-bearing optical film 1A according to the present embodiment is preferably 1.0 × 10 ¹² Ω / sq or lower, more preferably 5.0 × 10 ¹¹ Ω / sq or lower And more preferably 7.0 x ¹⁰ < 10 ^> OMEGA / sq or less. When the surface resistivity is equal to or less than the above value, sufficient antistatic property can be exhibited in the display panel. This surface resistivity can be attained by containing the above-described antistatic agent (D) in the adhesive composition (P). The measurement of the surface resistivity of the first pressure-sensitive adhesive layer 21 is carried out in accordance with JIS K6911, specifically as shown in the following test examples. The lower limit of the surface resistivity is not particularly limited, but is about 5.0 × 10 ⁸ Ω / sq from the viewpoint of not adversely affecting durability and heat resistance non-uniformity.

7. Use of optical film with adhesive layer

The optical film (1A) with a pressure-sensitive adhesive layer according to the present embodiment can be used as a complex polarizer with a pressure-sensitive adhesive layer by laminating a polarizer on the second retarder (12) like the optical film have. By using this complex polarizing plate with a pressure-sensitive adhesive layer, for example, a liquid crystal display device including a liquid crystal cell and a composite polarizing plate can be manufactured. More specifically, it will be described later in the section of the optical film (1B) with a pressure-sensitive adhesive layer.

[Optical film with pressure-sensitive adhesive layer according to the second embodiment]

3, the optical film (1B) with a pressure-sensitive adhesive layer according to the second embodiment of the present invention has a first retardation plate (11) and a second retardation plate (11b) And a second pressure-sensitive adhesive layer 21 laminated on the side of the first retardation plate 11 opposite to the side of the first pressure-sensitive adhesive layer 21 (upper side in Fig. 3) Layer 22 and a second retardation plate 12 laminated on the side of the second pressure-sensitive adhesive layer 22 opposite to the side of the first retardation plate 11 side (upper side in Fig. 3) And a polarizing plate 3 laminated on the side of the second retardation plate 12 opposite to the side of the second pressure-sensitive adhesive layer 22 side (upper side in Fig. 3). That is, the optical film (1B) with a pressure-sensitive adhesive layer according to the second embodiment is obtained by laminating the polarizing plate (3) on the pressure-sensitive adhesive layer-attached optical film (1A) according to the first embodiment. As a result, it is possible to provide a complex polarizing plate with a pressure-sensitive adhesive layer, which has a very excellent viewing angle compensation performance. The composite polarizing plate in the present embodiment is constituted by a first retardation plate 11, a second pressure sensitive adhesive layer 22, a second retardation plate 12 and a polarizing plate 3.

The first retardation plate 11, the first pressure-sensitive adhesive layer 21, the second pressure-sensitive adhesive layer 22 and the second retardation plate 12 in the pressure-sensitive adhesive layer-bearing optical film 1B according to the second embodiment, The first retardation plate 11, the first pressure-sensitive adhesive layer 21, the second pressure-sensitive adhesive layer 22 and the second retardation plate 12 in the optical film 1A with a pressure-sensitive adhesive layer according to the first embodiment, And has the same configuration. Although not shown, in the first pressure-sensitive adhesive layer 21, on the side opposite to the side of the first retardation plate 11 (the bottom in Fig. 3), until the optical film 1B with a pressure-sensitive adhesive layer is used , And a release sheet may be laminated.

The optical film (1B) with a pressure-sensitive adhesive layer is excellent in durability when used in a display panel even when the optical film (composite polarizing plate) to be used is thinner than the conventional one, The occurrence of lifting or peeling can be suppressed even under shock. Further, the display panel does not bend well even under high temperature conditions, and there is no heat unevenness.

1. Polarizer

The polarizing plate 3 in the present embodiment is provided with the polarizer 31 located on the side of the second retardation plate 12 and the protective layer 32 located on the opposite side of the second retardation plate 12 . Although not shown, an adhesive layer may be interposed between the polarizer 31 and the protective layer 32 and / or between the polarizer 31 and the second retarder 12.

(1) Polarizer

The polarizer 31 is preferably made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented.

The polyvinyl alcohol-based resin constituting the polarizer 31 is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and the like.

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

The polarizer 31 as described above is a step of uniaxially stretching a polyvinyl alcohol based resin film, a step of dying a polyvinyl alcohol based resin film with a dichroic dye, a step of adsorbing the dichroic dye, a step of dichroic dye being adsorbed Is subjected to a step of treating the polyvinyl alcohol-based resin film with an aqueous solution of boric acid.

The uniaxial stretching may be carried out before dyeing with a dichroic dye, or simultaneously with dyeing with a dichroic dye, or after dyeing with a dichroic dye. In the case where uniaxial stretching is carried out after dyeing with a dichroic dye, the uniaxial stretching may be carried out before the boric acid treatment or during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. In the case of uniaxial stretching, the uniaxial stretching may be performed between rolls having different circumferential speeds, or may be uniaxially stretched using a heat roll. In addition, it may be dry stretching in which stretching is performed in the atmosphere, or wet stretching in which stretching is performed in a state of being swollen with a solvent. The stretching magnification is usually about 4 to 8 times.

To dye a polyvinyl alcohol-based resin film with a dichroic dye, for example, a polyvinyl alcohol-based resin film may be immersed in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine or a dichroic organic dye is specifically used.

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

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution of boric acid. The content of boric acid in the aqueous solution of boric acid is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution of boric acid contains potassium iodide. The content of potassium iodide in the aqueous solution of boric acid is usually about 2 to 20 parts by mass, preferably 5 to 15 parts by mass, per 100 parts by mass of water. The immersing time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 占 폚 or higher, preferably 50 to 85 占 폚.

The polyvinyl alcohol-based resin film after treatment with boric acid is usually washed with water. The water washing treatment is carried out, for example, by immersing the boric acid-treated polyvinyl alcohol resin film in water. After washing with water, drying treatment is performed to obtain the polarizer 31. The temperature of the water in the water washing treatment is usually about 5 to 40 캜, and the immersing time is usually about 2 to 120 seconds. The drying treatment to be performed thereafter is usually carried out using a hot-air dryer or a far-infrared heater. The drying temperature is usually 40 to 100 占 폚. The drying treatment time is usually about 120 to 600 seconds.

The thickness of the polarizer 31 is preferably about 3 to 50 占 퐉, and particularly preferably about 3 to 15 占 퐉 when thinning is required.

(2) Protective layer

The protective layer 32 is preferably made of a transparent resin film. The transparent resin film constituting the protective layer 32 may be either an unstretched film or a uniaxially or biaxially stretched film.

The main component of the transparent resin film constituting the protective layer 32 is preferably at least one selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin, an amorphous polyolefin resin, and a cellulose resin Lt; / RTI > The protective layer 32 is preferably made of a cellulose-based resin.

As the cellulose-based resin, a mixed ester in which at least a part of the hydroxyl groups in cellulose is converted into an acetic acid ester and a part thereof is converted into acetic acid ester and partly esterified with another acid may be used. The cellulose-based resin is preferably a cellulose ester-based resin, more preferably an acetylcellulose-based resin. Specific examples of the acetylcellulose-based resin include triacetylcellulose, diacetylcellulose, cellulose acetate propionate, and cellulose acetate butyrate. Examples of the commercially available film of such an acetylcellulose resin film include "Fujitak TD80", "Fujitak TD80UF", and "Fujitac TD80UZ" manufactured by Fuji Film Co., Ltd., manufactured by Konica Minolta Opto Co., KC8U2M ", " KC2UA ", and " KC8UY "

As the protective layer 32, a cellulose resin film imparted with an optical compensation function may be used. Examples of such an optical compensation film include a film containing a compound having a retardation adjusting function in a cellulose resin, a film coated with a compound having a phase difference adjusting function on the surface of the cellulose resin, a cellulose resin having a single- , And the like. Examples of commercially available optical compensation films for cellulose resins include "Wide View Film WV BZ 438" and "Wide View Film WV EA" manufactured by Fuji Film Co., Ltd., "KC4FR- 1 " and " KC4HR-1 ".

Among the above-mentioned cellulose resins, the protective layer 32 is more preferably made of a cellulose ester resin, particularly preferably made of an acetylcellulose resin, more preferably made of triacetyl cellulose.

The protective layer 32 may contain an ultraviolet absorber. This is because the liquid crystal cell can be protected from deterioration by ultraviolet rays by disposing the protective layer containing the ultraviolet absorber on the visible side of the liquid crystal cell.

The adhesion layer may be subjected to an easy adhesion treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment or the like before the bonding to the polarizer 31. [ The surface of the protective layer 32 on the opposite side of the surface on which the polarizer 31 is adhered may have various treatment layers such as a hard coat layer, an antireflection layer, and an antiglare layer.

The thickness of the protective layer 32 is usually in the range of about 5 to 200 占 퐉, preferably 10 to 120 占 퐉, particularly preferably 10 to 85 占 퐉, and more preferably 10 to 30 占 퐉.

(3) Adhesive layer

The adhesive constituting the adhesive layer which may be interposed between the polarizer 31 and the protective layer 32 and / or between the polarizer 31 and the second retarder 12 may be an adhesive which, depending on the kind and purpose of the adherend, Appropriately suitable ones can be used. For example, a solvent type adhesive, an emulsion type adhesive, an aqueous adhesive, a pressure-sensitive adhesive, a moisture-resisting adhesive, a polycondensation adhesive, a solventless adhesive, a film-

One preferable adhesive constituting the adhesive is an aqueous adhesive, and a typical example thereof is a polyvinyl alcohol-based resin as a main component. Commercially available polyvinyl alcohol-based resins that can be water-based adhesives include, for example, " KL-318 " manufactured by Kuraray Co.,

The aqueous adhesive may contain a crosslinking agent. As the crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt and the like are preferable, and an epoxy compound is particularly preferable. Commercially available products of the crosslinking agent include, for example, glyoxal and "Sumireze Resin 650 (30)" which is an aqueous solution of a water-soluble epoxy compound sold by Sumika-Chemtech.

Another preferable adhesive is an adhesive comprising an epoxy resin composition containing an epoxy resin which is cured by irradiation with an active energy ray or heating. When the adhesive is used, the adhesion between the films can be carried out by irradiating the adhesive layer interposed between the films with an active energy ray or by heating to cure the curable epoxy resin contained in the adhesive. The curing of the epoxy resin by irradiation with active energy rays or heating is preferably carried out by cationic polymerization of an epoxy resin. In the present specification, the epoxy resin means a compound having two or more epoxy groups in the molecule.

From the viewpoints of weatherability, refractive index, cationic polymerization, and the like, the epoxy resin contained in the curable epoxy resin composition as the adhesive is preferably an epoxy resin which does not contain aromatic rings in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, and the like.

2. Manufacturing method of optical film with pressure-sensitive adhesive layer

A preferred example of the production method of the pressure-sensitive adhesive layer-containing optical film (1B) will be described.

(1) Production of composite polarizing plate

The composite polarizing plate can be produced by a conventional method. Hereinafter, as an example, a manufacturing method in the case of using an aqueous adhesive as the adhesive will be described.

First, a coating film of a pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 is formed on the release surface of the release sheet. Specifically, the coating solution of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22 is coated on the release surface of the release sheet and dried.

On the other hand, an adhesive layer is formed on the concave surface of the polarizer 31 or on the concave surface of the second retardation plate 12 and the protective layer 32. For forming the adhesive layer, for example, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, a gravure coat method and the like can be used. It is also possible to employ a method in which the polarizer 31 and the protective layer 32 are continuously supplied so that the concave surfaces of the polarizer 31 and the protective layer 32 are inwardly and the adhesive is softened therebetween. When the adhesive is applied, heat treatment is carried out if necessary to evaporate the moisture, and the adhesive layer is dried.

The film thickness of the adhesive layer can be arbitrarily set by the characteristic design of the polarizing plate 3, but from the viewpoint of reducing the adhesive material cost, the film thickness is preferably small, and from the viewpoint of suppressing defects such as bubbles and foreign substances at the time of co- From the viewpoints of adhesion and durability, it is preferable to carry out in an optimum range determined for each combination of adherend and adhesive. In general, it is 0.005 to 10 mu m, preferably 0.01 to 5 mu m, and more preferably 0.03 to 1 mu m.

In bonding the second retardation plate 12 and the polarizer 31 or the polarizer 31 and the protective layer 32 to each other, one or both of the coplanar surfaces of the polarizer 31 and the polarizer 31 are coated with a corona discharge An easy adhesion treatment such as a treatment, a plasma treatment, a flame treatment, a primer treatment, and an anchor coating treatment may be performed.

When the adhesive layer is formed as described above, the protective layer 32 is adhered to one surface of the polarizer 31 via the adhesive layer, and the second retardation plate 12 is adhered to the surface of the polarizer 31 And laminated on the other side to obtain a laminate composed of the protective layer 32, the polarizer 31 and the second retarder 12.

Next, a coating film of a pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer (22) on the release sheet is applied to the surface of the obtained laminate on the side of the second retardation plate (12). Then, an active energy ray is irradiated onto the peeling sheet to cure the coating film of the pressure-sensitive adhesive, and the coating film is used as the second pressure-sensitive adhesive layer (22). The irradiation conditions of the active energy ray and the like are the same as the above-mentioned production method of the optical film (1A) with a pressure-sensitive adhesive layer.

Finally, the release sheet is peeled from the second pressure-sensitive adhesive layer 22 formed as described above, and the second acrylic resin layer 113 of the first retardation plate 11 is exposed to the exposed second pressure- Side surface. Thus, a composite polarizing plate comprising the protective layer 32, the polarizer 31, the second retardation plate 12, the second pressure-sensitive adhesive layer 22 and the first retardation plate 11 laminated is obtained.

The total thickness of the composite polarizing plate is preferably 20 to 300 占 퐉, more preferably 30 to 150 占 퐉, and particularly preferably 50 to 100 占 퐉.

(2) Production of pressure-sensitive adhesive sheet for first pressure-sensitive adhesive layer

On the other hand, a pressure-sensitive adhesive sheet is produced by laminating a release sheet on one side or both sides of a first pressure-sensitive adhesive layer 21 formed from a pressure-sensitive adhesive composition (P). Here, as an example, a pressure-sensitive adhesive sheet comprising a release sheet laminated on both surfaces of a first pressure-sensitive adhesive layer 21 is to be manufactured. This pressure-sensitive adhesive sheet can be produced by the method described in the production method of the pressure-sensitive adhesive layer-equipped optical film (1A).

(3) Production of optical film with pressure-sensitive adhesive layer

From the pressure-sensitive adhesive sheet thus obtained, one of the release sheets (the thin release type release sheet) is peeled off. Then, the first retardation plate 11 of the composite polarizing plate is superposed on the exposed first pressure-sensitive adhesive layer 21, and the adhesive sheet and the complex polarizing plate are pressed. Thus, the above-mentioned pressure-sensitive adhesive layer-attached optical film 1B (with a release sheet) is obtained.

Another example of the production method of the optical film (1B) with a pressure-sensitive adhesive layer is a method in which a coating solution of the above-described pressure-sensitive adhesive composition (P) is applied to the release surface of the release sheet, a heat treatment is performed to form a coating film, And the first retardation plate 11 of the composite polarizing plate is superimposed on the film. When the curing period is required, the curing period is set so that the coating film becomes the first pressure-sensitive adhesive layer 21 when the curing period is unnecessary. Thus, the above-mentioned pressure-sensitive adhesive layer-attached optical film 1B (with a release sheet) is obtained.

3. Properties of Optical Film with Adhesive Layer

The pressure-sensitive adhesive layer-attached optical film (1B) according to the present embodiment has the same adhesive force and surface resistivity as the above-mentioned pressure-sensitive adhesive layer-attached optical film (1A).

4. Use of optical film with adhesive layer

By using the optical film (1B) with a pressure-sensitive adhesive layer, for example, a liquid crystal display device including a liquid crystal cell and a complex polarizing plate can be manufactured.

Specifically, the first pressure-sensitive adhesive layer 21 (the first pressure-sensitive adhesive layer 21 exposed by peeling off the release sheet when the release sheet is laminated) of the optical film 1B with the pressure-sensitive adhesive layer, And then press-bonded. As a result, a liquid crystal display device including a liquid crystal cell and a complex polarizing plate can be obtained.

Since the first pressure-sensitive adhesive layer 21 of the optical film 1B with a pressure-sensitive adhesive layer according to the present embodiment is excellent in durability, even if the obtained liquid crystal display device is placed under a high temperature condition under a humid condition or under a heat shock, The occurrence of lifting or peeling at the interface of the layer 21 is suppressed. For example, when a glass plate to which the optical film (1B) with a pressure-sensitive adhesive layer is attached is placed under a high temperature condition of 85 DEG C for 250 hours under a wet heat condition of 60 DEG C and 90% RH or a heat shock of -35 DEG C to 70 DEG C 30 minutes, 200 cycles) is given, the occurrence of lifting or peeling is suppressed.

In addition, since the first pressure-sensitive adhesive layer 21 of the optical film (1B) with a pressure-sensitive adhesive layer according to the present embodiment is also excellent in stress relaxation property, the obtained liquid crystal display device does not bend well under high temperature conditions, This is not good. For example, even when a glass plate to which the optical film (1B) with a pressure-sensitive adhesive layer is attached is left for 250 hours under a high-temperature condition (for example, at a temperature of 80 to 85 캜), the glass plate does not bend well, Do not. Particularly, even if the composite polarizing plate is a thin film, the liquid crystal display does not bend well, and even if the liquid crystal cell is high-precision, heat unevenness does not occur easily.

A transparent conductive film may be present on the surface of the liquid crystal cell in contact with the first pressure-sensitive adhesive layer (21). Examples of the transparent conductive film include metals such as platinum, gold, silver and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide and zinc dioxide, indium tin oxide (ITO) A non-oxidizing compound such as chalcogenide, lanthanum pentoxide, titanium nitride, titanium carbide, or the like, which is a composite oxide such as indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, indium tin oxide, .

The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents falling within the technical scope of the present invention.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]

1. Fabrication of Optical Film (Composite Polarizer)

(1) Production of polarizer

A polyvinyl alcohol film having a thickness of 75 탆 and composed of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more was uniaxially stretched by about 5 times in a dry state and maintained at a stretching temperature of 1 Lt; / RTI > Thereafter, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C for 60 seconds. Subsequently, the substrate was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C for 300 seconds. Subsequently, the film was washed with pure water at 26 DEG C for 20 seconds, and then dried at 65 DEG C to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol.

(2) Production of Polarizer

3 parts by mass of a carboxyl group-modified polyvinyl alcohol (trade name: "KL-318", manufactured by Kuraray Co., Ltd.) was dissolved in 100 parts by mass of water. To the aqueous solution was added a polyamide epoxy additive 1.5 parts by mass of an aqueous solution having a solid content concentration of 30% by mass (trade name, Sumirei Resin 650 (30), manufactured by Kankuchi Kogyo Co., Ltd.) was prepared. The epoxy adhesive was applied to one surface of the polarizer obtained above.

A triacetyl cellulose film (trade name: "KC2UA", manufactured by Konica Minolta Opto Co., Ltd.) having a thickness of 25 μm and subjected to saponification treatment on its surface was applied to the coating layer of the epoxy adhesive as the protective layer, A polarizing plate obtained by laminating polarizers was obtained.

(3) Production of a laminate including a polarizing plate and a second retardation plate

Next, an epoxy adhesive was applied to the other surface of the polarizer of the polarizing plate in the same manner as described above, and as the second retardation plate, a cyclic olefin resin having a thickness of 23 占 퐉 (Trade name " ZEONOR ", manufactured by Nippon Zeon Co., Ltd.). And then dried at 80 DEG C for 5 minutes to adhere the first protective layer and the second protective layer to the polarizer. After adhering, the laminate was cured at 40 占 폚 for 168 hours to give a total thickness of 63 (thickness: 25 占 퐉) formed by laminating a protective layer (layer thickness 25 占 퐉), a polarizer (stretching magnification 5 times, layer thickness 15 占 퐉) Mu m thick.

(4) Formation of coating film of active energy ray-curable pressure-sensitive adhesive

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

100 parts by mass of the above-mentioned (meth) acrylic acid ester polymer (X) and 30 parts by mass of tris (acryloxyethyl) isocyanurate (trade name: Aronix M- 315 "), 0.3 part by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name " Coronate L ") as a crosslinking agent (Z), and 0.1 part by mass of benzophenone and 1-hydroxycyclo 1.5 parts by mass of a mixture of hexyl phenyl ketone in a mass ratio of 1: 1 (manufactured by Chiba Specialty Chemicals Co., Ltd., trade name "Irgacure 500") and 3 parts by mass of 3-glycidoxypropyltrimethoxysilane Manufactured by Kagaku Kogyo K.K., trade name " KBM403 ") were mixed and sufficiently stirred and diluted with ethyl acetate to obtain a coating solution of the active energy ray-curable pressure-sensitive adhesive.

The coating solution of the obtained active energy ray-curable pressure-sensitive adhesive was coated with a knife coater on the release surface of a release sheet (SP-PET3811, manufactured by Lin Tec Co., Ltd., thickness: 38 占 퐉) in which one side of the polyethylene terephthalate film was peeled off with a silicone- Thereafter, the film was heat-treated at 90 ° C for 1 minute to form a coating film of an active energy ray-curable pressure-sensitive adhesive.

(5) Fabrication of first retardation plate

(Manufactured by Sumitomo Chemical Co., Ltd., trade name: " Technoloy S001 ") in which about 20 mass% of acrylic rubber particles having an average particle diameter of 200 nm constituting the first acrylic resin layer was blended, and a retardation- (Trade name " Dairak D332 ", trade name, manufactured by Nova Chemical Co., Ltd.) and about 20 mass% of acrylic rubber particles having an average particle diameter of 200 nm constituting the second acrylic resin layer Resin (trade name: "Technoloy S001", manufactured by Sumitomo Chemical Co., Ltd.) was co-extruded in this order to obtain a laminated film having a three-layer structure. The resulting laminated film was stretched to obtain a first retardation plate (first acrylic resin layer / phase retardation layer / second acrylic resin layer) having an in-plane retardation value of 60 nm and a thickness of 25 占 퐉.

(6) Fabrication of composite polarizer

A coating film of the active energy ray-curable pressure-sensitive adhesive obtained in the above step (4) was applied to the side of the second retardation plate in the laminate obtained in the step (3), and ultraviolet rays were irradiated onto the release sheet under the following conditions , And the coated film of the pressure-sensitive adhesive was cured to form a second pressure-sensitive adhesive layer. Thereafter, the release sheet was peeled from the obtained second pressure-sensitive adhesive layer, and the surface of the first retardation plate obtained in the step (5) on the side of the second acrylic resin layer was bonded to the surface of the exposed second pressure- Respectively. Thus, a composite polarizing plate (optical film) having a total thickness of 93 탆 was obtained by laminating a protective layer, a polarizer, a second retardation plate, a second pressure-sensitive adhesive layer and a first retardation plate. The thickness of the formed second pressure sensitive adhesive layer was 5 mu m.

<Ultraviolet irradiation condition>

· Using high pressure mercury lamp

Illumination 300 mW / cm ² , light quantity 300 mJ / cm ²

· UV illuminance · "UVPF-A1" manufactured by Eye Graphics Co., Ltd.

2. Production of optical film with pressure-sensitive adhesive layer

(1) Preparation of (meth) acrylic acid ester copolymer

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

(2) Preparation of adhesive composition

100 parts by mass of the (meth) acrylic acid ester copolymer (A) obtained in the above step (1) and 0.2 parts by mass of trimethylolpropane-modified xylylene diisocyanate (trade name "Takenate D110N" And 0.2 part by mass of 3-glycidoxypropyltrimethoxysilane (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) as the epoxy group-containing silane coupling agent (C1) , 0.2 part by mass of a co-condensate of mercaptopropyltrimethoxysilane and methyltriethoxysilane (trade name "X-411-1810", trade name, manufactured by Shin-Etsu Chemical Co., Ltd., mercapto equivalent: 450 g / ) And 2.0 parts by mass of N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound which is solid at room temperature) were mixed, sufficiently stirred, and diluted with ethyl acetate to obtain a coating solution of the adhesive composition .

Table 1 shows the respective blend (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester copolymer (A) was changed to 100 parts by mass (solid content conversion value). Details of the abbreviations and the like in Table 1 are as follows.

[(Meth) acrylic acid ester copolymer]

BA: n-butyl acrylate

HEA: 2-hydroxyethyl acrylate

IBXA: isobornyl acrylate

PhEA: 2-phenylethyl acrylate

CHA: cyclohexyl acrylate

2EHA: 2-ethylhexyl acrylate

[Isocyanate-based crosslinking agent]

XDI: trimethylolpropane-modified xylylene diisocyanate (trade name &quot; Takenate D110N &quot;, manufactured by Mitsui Chemicals, Inc.)

TDI: trimethylolpropane-modified tolylene diisocyanate (trade name &quot; Colonate L &quot;, manufactured by Nippon Polyurethane Industry Co., Ltd.)

[Antistatic Agent]

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

(3) Production of optical film with pressure-sensitive adhesive layer

The coating solution of the obtained sticky composition was applied to a release treatment surface of a release sheet (SP-PET3811, manufactured by Lin Tec Co., Ltd., thickness: 38 占 퐉) having one surface of a polyethylene terephthalate film peeled off with a silicone-based release agent by a knife coater, Followed by heat treatment at 90 占 폚 for 1 minute to form a coating film of the adhesive composition.

Subsequently, the composite polarizing plate obtained above was laminated with the coating film so that the surface of the first acrylic resin layer in the first retardation plate and the exposed surface of the coating film were in contact with each other. Curing for one day to obtain an optical film with a pressure-sensitive adhesive layer, in which a pressure-sensitive adhesive layer was formed on the composite polarizing plate. The thickness of the formed pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) was 20 占 퐉.

[Examples 2 to 13, Comparative Example 1]

The type and proportion of each monomer constituting the (meth) acrylic acid ester copolymer (A), the weight average molecular weight of the (meth) acrylic acid ester copolymer (A), and the type and amount of the crosslinking agent (B) An optical film with a pressure-sensitive adhesive layer was prepared in the same manner as in Example 1, except that the pressure-sensitive adhesive layer was changed as described above.

[Comparative Example 2]

A coating film (see Table 1) obtained by adding an antistatic agent (D) to a pressure-sensitive adhesive having the same composition as that of the second pressure-sensitive adhesive layer used in the formation of the first pressure-sensitive adhesive layer was peeled off from the release sheet SP-PET3811, thickness: 38 mu m), and the resultant was laminated so that the outermost surface of the first retardation plate of the composite polarizing plate and the exposed surface of the coated film were in contact with each other. Then, ultraviolet rays were irradiated onto the peeled sheet under the following conditions, Subsequently, an optical film with a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) was formed on the composite polarizing plate was produced in the same manner as in Example 1 except that the curing was continued at 23 ° C and 50% RH for 7 days. The thickness of the first pressure-sensitive adhesive layer was 20 占 퐉.

<Ultraviolet irradiation condition>

· Using high pressure mercury lamp

Illumination 300 mW / cm ² , light quantity 300 mJ / cm ²

· UV illuminance · "UVPF-A1" manufactured by Eye Graphics Co., Ltd.

The weight average molecular weight (Mw) described above is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement Conditions>

GPC measurement apparatus: HLC-8020 manufactured by Toso Co., Ltd.

· GPC Column (Pass in the following order): Toso Co., Ltd.

  TSK guard column HXL-H

  TSK gel GMHXL (× 2)

  TSK gel G2000HXL

Measurement solvent: tetrahydrofuran

· Measuring temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

(SP-PET3801, manufactured by Lin Tec Corp., thickness: 38 mu m) in which one side of the polyethylene terephthalate film was peeled off with a silicone-based releasing agent was used in place of the optical film used in the production of the optical film with an adhesive layer in Examples and Comparative Examples To prepare a pressure-sensitive adhesive sheet. Specifically, on the coated film on which the constituent material of the coating film of the release sheet / adhesive composition (for the first pressure-sensitive adhesive layer) obtained in the manufacturing process of the embodiment or the comparative example is exposed, the release sheet is peeled And cured for 7 days under conditions of 23 캜 and 50% RH. Thus, a pressure-sensitive adhesive sheet having the constitution of a release sheet (SP-PET3801) / first pressure-sensitive adhesive layer (thickness: 20 占 퐉) / release sheet (SP-PET3811) was produced. In the preparation of the pressure-sensitive adhesive sheet having the first pressure-sensitive adhesive layer (thickness: 20 占 퐉) of Comparative Example 2, ultraviolet radiation was applied before curing in the same manner as in the case of the production of the pressure-

The pressure-sensitive adhesive sheet thus obtained was cut into a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer was wrapped in a polyester mesh (mesh size 200), the mass thereof was weighed with a precision balance and the mass of the mesh alone was subtracted, And the mass of each of them was calculated. The mass at this time is denoted by M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 DEG C) for 24 hours. Thereafter, the pressure-sensitive adhesive was taken out and air-dried for 24 hours under an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the mesh alone was subtracted to calculate the mass of the adhesive alone. The mass at this time is M2. The gel fraction (%) is expressed by (M2 / M1) x100. The results are shown in Table 2.

The gel fraction (%) was also measured for the second pressure-sensitive adhesive layer formed by curing the coating film of the active energy ray-curable pressure-sensitive adhesive formed in the examples and the comparative examples in the same manner as described above. The results are shown in Table 2.

[Test Example 2] (Measurement of storage elastic modulus)

A pressure-sensitive adhesive sheet composed of a release sheet (SP-PET3801) / first pressure-sensitive adhesive layer (thickness: 20 占 퐉) / release sheet (SP-PET3811) was prepared in the same manner as in Test Example 1.

In the same manner as in Examples and Comparative Examples, except that a release sheet (SP-PET3801) and a release sheet (SP-PET3811) were respectively used instead of the polarizing plate and the first retardation plate in the optical film, Sensitive adhesive sheet having the structure of SP-PET3801 / second pressure-sensitive adhesive layer (thickness: 5 占 퐉) / release sheet (SP-PET3811)

A plurality of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed in the above process were laminated so as to have a thickness of 3 mm. A cylindrical body (height 3 mm) having a diameter of 8 mm was struck from the obtained laminate of the pressure-sensitive adhesive layer, and this was sampled.

With respect to the sample, the storage elastic modulus (MPa) was measured by a twist shearing method using a viscoelasticity measuring instrument (DYNAMIC ANALAYZER, manufactured by REOMETRIC Co., Ltd.) according to JIS K7244-6 under the following conditions. The results are shown in Table 2.

Measuring frequency: 1 Hz

Measuring temperature: 85 ° C

[Test Example 3] (Evaluation of durability)

The optical film with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut to prepare a sample having a size of 150 mm x 200 mm. The release sheet was peeled off from the sample and attached to an alkali-free glass (Eagle XG, manufactured by Corning Incorporated) through the exposed pressure-sensitive adhesive layer, followed by pressurization at 0.5 MPa and 50 ° C for 20 minutes with an autoclave manufactured by Kurihara Seisakusho .

Thereafter, the mixture was put under the conditions of the following three durability conditions, and after 250 hours, a 10-fold loupe was used to confirm whether or not it was lifted or peeled off. The evaluation criteria are as follows. The results are shown in Table 2.

◎: No peeling or peeling was observed.

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

[Delta]: Excoriation or exfoliation of not less than 0.5 mm and not more than 1.0 mm was confirmed.

X: Exfoliation or peeling of a size exceeding 1.0 mm was confirmed.

&Lt; Durability condition &

· Heat resistance: 85 ℃ dry

· Humidity: 60 ℃, relative humidity 90% RH

H.S. : Heat shock test for 30 minutes at -35 ° C to 70 ° C, 200 cycles

[Test Example 4] (Evaluation of warpage resistance)

The optical films with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples were cut to a length of 200 mm and a width of 150 mm. The release sheet was peeled from the optical film with the pressure-sensitive adhesive layer, and the exposed pressure-sensitive adhesive layer was laminated to the center of a non-alkali glass (trade name "Eagle-XG", manufactured by Corning Incorporated) having a length of 250 mm, a width of 175 mm and a thickness of 0.5 mm , And this was taken as a sample. This sample was allowed to stand in a dry atmosphere at 85 캜 for 250 hours. Thereafter, the sample was taken out under an environment of 25 ° C and 50% RH, placed on a horizontal stand with the optical film side up, and the amount of deflection (the distance between the edge and the stand) from each corner of the sample (4 points) The amount of deflection of each edge was totaled. Based on the results, the warpage resistance was evaluated as follows. The results are shown in Table 2.

?: The total amount of deflection is not more than 10 mm

○: The total amount of deflection exceeds 10 mm, 15 mm or less

?: The total amount of deflection is more than 15 mm and not more than 20 mm

X: The total amount of deflection exceeds 20 mm

[Test Example 5] (Evaluation of heat non-uniformity)

The optical film with the pressure-sensitive adhesive layer obtained in the examples and the comparative examples was adjusted to a size of 200 mm x 150 mm by using a cutting device (super cutter, manufactured by Oji Paper Manufacturing Co., Ltd., PN1-600). The release sheet was peeled off and pasted to an alkali-free glass (Eagle XG, manufactured by Corning) through the exposed pressure-sensitive adhesive layer, followed by pressurization at 0.5 MPa and 50 占 폚 for 20 minutes with an autoclave manufactured by Kurihara Seisakusho. The bonding was performed so that the polarizing axis of the optical film with a pressure-sensitive adhesive layer was in the cross-Nicol state (polarizing axis: 45 deg., 135 deg.) On the front and back of the alkali-free glass. In this state, the sample was allowed to stand in a dry environment at 80 占 폚 for 250 hours, then left in an environment of 23 占 폚 and 50% RH for 2 hours. Using the sample as a sample, the thermal non-uniformity was evaluated by the following method. The results are shown in Table 2.

<Evaluation method>

The sample was placed on a flat illuminator (HF-SL-A312LC, illuminance: 26,000 Lux, luminance: 10,000 cd, manufactured by Dentsu Ind.) And photographed with a two-dimensional color intensity meter (CA-2000 manufactured by Konica Minolta Co., And converted into a luminance distribution image by analysis software (CA-S20w, manufactured by Konica Minolta Co., Ltd.). The luminance distribution image of the obtained sample was evaluated based on Fig. 4 and the following evaluation criteria.

?: The luminance distribution is almost uniform.

?: There are some variations in the luminance distribution on the four sides.

?: There is a clear variation in the luminance distribution of four sides.

X: There is a severe deformation in the luminance distribution of four sides.

[Test Example 6] (Adhesive strength measurement - Reheat property evaluation)

A sample of 25 mm width and 100 mm length was cut out from the optical film with a pressure-sensitive adhesive layer obtained in the Examples and Comparative Examples, the release sheet was peeled off, and an alkali-free glass (Eagle XG manufactured by Corning Incorporated) And then pressed at 0.5 MPa and 50 캜 for 20 minutes with an autoclave manufactured by Kurihara Seisakusho Co., Ltd. Thereafter, the substrate was allowed to stand under the conditions of 23 ° C and 50% RH for 24 hours, and then subjected to a tensile tester (Tencilon, manufactured by Orientech) under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 ° N / 25 mm) was measured. Conditions other than those described herein were measured in accordance with JIS Z 0237: 2009. The results are shown in Table 2.

The adhesive strength (adhesive strength after 14 days of application; N / 25 mm) was measured in the same manner as above after being left under the conditions of 23 캜 and 50% RH for 14 days. Apart from this, the adhesive strength (adhesive strength after 2 days at 50 ° C: N / 25 mm) was measured in the same manner as described above after being left under the conditions of 50 ° C and 50% RH for 2 days. The results are shown in Table 2.

Based on the adhesive strength after 14 days of the application, the evaluation of the reworkability was carried out according to the following criteria. The results are shown in Table 2.

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

○: Adhesive strength after 14 days of application exceeding 8.8 N / 25 mm, less than 10 N / 25 mm

?: Adhesive strength after 14 days of application of 10 N / 25 mm or more, less than 20 N / 25 mm

X: Adhesive strength after 14 days of application is 20 N / 25 mm or more

[Test Example 7] (Measurement of surface resistivity of pressure-sensitive adhesive layer)

The optical film with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 50 mm x 50 mm, and the obtained sample was left for 24 hours at a temperature of 23 DEG C and a humidity of 50% RH. Thereafter, the release sheet was peeled off and the surface resistivity (Ω / sq) was measured according to JIS K6911 using a resistivity meter (Hiresta UP MCP-HT450 type, manufactured by Mitsubishi Chemical Co., ) Were measured. The results are shown in Table 2.

As can be seen from Table 2, the optical film with a pressure-sensitive adhesive layer obtained in the examples was excellent in durability, and did not bend well under high temperature and did not generate heat unevenness. In the optical film with a pressure-sensitive adhesive layer obtained in Examples, the surface resistivity of the pressure-sensitive adhesive layer was low and the adverse effect on the liquid crystal cell was small. In addition, the optical films with the pressure-sensitive adhesive layer obtained in Examples 1 to 12 were also excellent in workability.

The optical film with a pressure-sensitive adhesive layer according to the present invention is suitable for bonding a liquid crystal cell and a composite polarizing plate formed into a thin film.

1A, 1B: Optical film with pressure-sensitive adhesive layer
11: First retardation plate
111: a first acrylic resin layer
112: phase difference developing layer
113: Second acrylic resin layer
12: second retardation plate
21: first pressure-sensitive adhesive layer
22: second pressure-sensitive adhesive layer
3: polarizer
31: Polarizer
32: Protective layer

Claims (7)

A first retardation plate,
A first pressure-sensitive adhesive layer laminated on one side of the first retarder;
A second pressure-sensitive adhesive layer laminated on a side of the first retarder opposite to the side of the first pressure-sensitive adhesive layer side;
A second retardation plate laminated on a side of the second pressure-sensitive adhesive layer opposite to the side of the first retardation plate,
Sensitive adhesive layer-containing optical film,
Wherein the surface of the first retardation film which is in contact with the first pressure sensitive adhesive layer is made of acrylic resin,
The gel fraction of the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer is 55 to 90%
The storage elastic modulus (G ') of the first pressure-sensitive adhesive layer at 85 캜 is 0.03 to 0.25 MPa,
The gel fraction of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer is 80 to 100%
Wherein the storage elastic modulus (G ') of the second pressure-sensitive adhesive layer at 85 캜 is 0.15 to 3.00 MPa. The method according to claim 1,
Wherein the outermost surface layer in contact with the first pressure-sensitive adhesive layer in the first retarder comprises an acrylic resin layer formed through extrusion molding. 3. The method of claim 2,
Wherein the first retardation plate comprises:
The acrylic resin layer,
A second acrylic resin layer,
A phase difference developing layer disposed between the acrylic resin layer and the second acrylic resin layer,
And a pressure-sensitive adhesive layer. The method of claim 3,
The optical film with a pressure-sensitive adhesive layer, wherein the retardation-generating layer is made of a styrene-based resin. The method according to claim 1,
The optical film with a pressure-sensitive adhesive layer, wherein the second retarder is composed of a cyclic olefin-based resin. The method according to claim 1,
Wherein the first pressure-sensitive adhesive layer comprises:
(Meth) acrylic acid ester copolymer (A) containing an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer,
The crosslinking agent (B)
And a pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing the pressure-sensitive adhesive layer. The method according to claim 1,
Wherein a polarizing plate is further laminated on the side of the second retarder opposite to the side of the second pressure-sensitive adhesive layer side.

Images