TW201643480A - Optical film attached with adhesive layers - Google Patents

Abstract

The present invention provides an optical film attached with adhesive layers which is excellent in durability and is less liable to warp and less likely to cause thermal unevenness even when a thinned optical film is used. An optical film (1A) attached with adhesive layers comprises: a first retardation film (11); a first adhesive layer (21) laminated on one surface of the first retardation film (11); a second adhesive layer (22) laminated on the first retardation film (11) at one side opposite to the surface of the first adhesive layer (21); and a second retardation film (12) laminated on the second adhesive layer (22) at one side opposite to the surface of the first retardation film (11). In this optical film (1A) attached with adhesive layers, the surface between the first retardation film (11) and the first adhesive layer (21) is composed of an acrylic resin, a gel fraction of the adhesive constituting the first adhesive layer (21) is 55 to 90%, and the storage elastic modulus (G') of the first adhesive layer at 85 DEG C is 0.03 to 0.25 MPa, a gel fraction of the adhesive constituting the second adhesive layer (22) is 80 to 100%, and the storage elastic modulus (G') of the second adhesive layer (22) at 85 DEG C is 0.15 to 3.00 MPa.

Description

Optical film with adhesive layer

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

In recent years, as a display panel of various electronic devices, a touch panel that doubles as a display device and an input mechanism has been widely used. The types of touch panels are mainly resistive film type, capacitive type, optical type and ultrasonic type, resistive film type has analog film type and matrix resistive film type; capacitive type has surface type and projection type.

Projection type capacitors are widely used in touch panels of mobile electronic devices such as smart phones or tablets that have recently attracted attention. As a projection type capacitive touch panel of a related mobile electronic device, for example, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, and a transparent layer are laminated in this order. Protective sheet for conductive film (ITO) and tempered glass.

As the optical component constituting the above liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell is usually disposed such that an alignment layer of two transparent electrode substrates forming an alignment layer is formed inside, and a spacer is formed at a predetermined interval, and a liquid crystal material is sandwiched between the two transparent electrode substrates. Usually, the outer sides of the two transparent electrode substrates in the liquid crystal cell are respectively adhered by an adhesive There is a composite polarizer having a polarizing plate or a phase difference plate.

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

[Previous Technical Literature] [Patent Literature]

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

Here, with the demand for thinning of mobile electronic devices in recent years, thin films have been required for optical films such as polarizing plates. However, the polarizing plate of the film has a high shrinkage rate due to heat or the like. In the conventional adhesive such as Patent Document 1, the display panel may be warped or may be lifted or surfaced under high temperature conditions or under moist heat conditions. Stripped. It is also pointed out that due to the stress at the time of thermal shrinkage of the optical film, there is a problem of light leakage (so-called heat unevenness) caused by the deviation of the optical axis of the optical film.

The present invention has been made in view of such an actual situation, and an object thereof is to provide an adhesive which is excellent in durability, a display panel which is not easily warped, and which is less prone to heat unevenness even when a thinned optical film is used. An optical film of the agent layer.

In order to achieve the above object, the present invention provides an optical film having an adhesive layer, comprising: a first retardation film; a first adhesive layer laminated on one surface of the first retardation film; a second adhesive layer on the side opposite to the surface on the side of the first adhesive layer on the retardation plate; and a layer on the side opposite to the surface on the side of the first retardation plate of the second adhesive layer In the second retardation film, the surface of the first retardation film that is in contact with the first adhesive layer is made of an acrylic resin, and the first adhesive layer is formed of the first adhesive layer. The gel fraction of the adhesive is 55 to 90%, and the storage elastic modulus (G') of the first adhesive layer at 85 ° C is 0.03 to 0.25 MPa, which constitutes the adhesion of the adhesive of the second adhesive layer. The gel fraction is 80 to 100%, and the storage elastic modulus (G') at 85 ° C of the second adhesive layer is 0.15 to 3.00 MPa (Invention 1).

According to the invention (Invention 1), the surface in contact with the adhesive layer of the optical film is made of an acrylic resin, and when the optical film has been thinned, the first adhesive layer and the second adhesive layer can also be used. The adhesive layer satisfies the above physical properties, and thus is excellent in durability when used in a display panel, and the display panel is less likely to warp, and heat unevenness is less likely to occur.

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

In the first aspect of the invention, the first retardation film includes the acrylic resin layer, the second acrylic resin layer, and a phase difference expression between the acrylic resin layer and the second acrylic resin layer. Floor It is preferred (Invention 3).

In the above invention (Invention 3), the phase difference expression layer is preferably composed of a styrene resin (Invention 4).

In the above inventions (1 to 4), the second retardation film is preferably composed of a cyclic olefin resin (Invention 5).

In the above inventions (1 to 5), the first adhesive layer is composed of an adhesive obtained from an adhesive composition, and the adhesive composition contains (meth)acrylate copolymer (A) containing fat. The cyclic structural monomer (a1) and the aromatic ring-containing monomer (a2); and the crosslinking agent (B) are used as a monomer unit constituting the polymer (Invention 6).

In the above invention (Inventions 1 to 6), it is preferable to laminate a polarizing plate on the side opposite to the surface on the side of the second adhesive layer on the second retardation plate (Invention 7).

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

1A, 1B‧‧‧ Optical film with adhesive layer

11‧‧‧1st phase difference plate

111‧‧‧1st acrylic resin layer

112‧‧‧ phase difference performance layer

113‧‧‧2nd acrylic resin layer

12‧‧‧2nd phase difference plate

21‧‧‧1st adhesive layer

22‧‧‧2nd adhesive layer

3‧‧‧Polar plate

31‧‧‧Polar photons

32‧‧‧Protective layer

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an optical film with an adhesive layer according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a configuration example of a phase difference plate.

Fig. 3 is a cross-sectional view showing an optical film with an adhesive layer according to another embodiment of the present invention.

Fig. 4 is a view (color) showing the evaluation criteria of the heat resistance unevenness test (visual observation) of the optical film with the adhesive layer.

Hereinafter, embodiments of the present invention will be described.

[Optical film with an adhesive layer according to the first embodiment]

As shown in Fig. 1, the optical film 1A with an adhesive layer according to the first embodiment of the present invention is configured to include a first retardation film 11 and a layer laminated on the first retardation film 11 (the lower side in Fig. 1). a first adhesive layer 21; a second adhesive layer 22 laminated on one surface side (upper side in FIG. 1) opposite to the surface on the first adhesive layer 21 side of the first retardation film 11; and a laminate The second retardation film 12 on the opposite side (the upper side in FIG. 1) of the second adhesive layer 22 on the side opposite to the surface on the first retardation film 11 side. The surface of the first retardation film 11 that is in contact with the first adhesive layer 21 is made of an acrylic resin. Further, the gel fraction of the adhesive constituting the first adhesive layer 21 is 55 to 90%, and the storage elastic modulus (G') at 85 °C of the first adhesive layer 21 is 0.03 to 0.25 MPa. Further, the gel fraction of the adhesive constituting the second adhesive layer 22 is 80 to 100%, and the storage elastic modulus (G') at 85 ° C of the second adhesive layer 22 is 0.15 to 3.00 MPa.

In the optical film 1A with the adhesive layer described above, even the optical film (the laminated body of the first retardation film 11, the second adhesive layer 22, and the second retardation film 12) to be used is compared with a conventional product. When the film is formed, it is excellent in durability when used in a display panel, and can suppress the occurrence of warping or surface peeling under high temperature conditions, under moist heat conditions or under thermal shock. In addition, the above display panel is not easy to warp under high temperature conditions, and is not easy to generate heat. All. This effect is mainly caused by the conditions in which the first adhesive layer 21 and the second adhesive layer 22 are composed of an adhesive satisfying the above physical properties, and the first adhesive layer 21 composed of an adhesive satisfying the above physical properties, and The surface in which the first adhesive layer 21 is in contact with each other is realized by combining the first retardation plates 11 made of an acrylic resin.

Further, as described above, the first retardation film 11 and the second retardation film 12 are provided, whereby an excellent viewing angle can be exhibited in a liquid crystal display device, particularly an IPS (In-Place-Switching) liquid crystal display device. Compensation performance.

The gel fraction of the adhesive constituting the first adhesive layer 21 is 55 to 90%, preferably 65 to 85%, particularly preferably 73 to 78%, as described above. When the gel fraction is less than 55%, the durability of the obtained display panel is lowered, and when it exceeds 90%, the display panel is easily warped under high temperature conditions, and thermal unevenness is likely to occur.

The gel fraction of the adhesive constituting the second adhesive layer 22 is 80 to 100%, preferably 85 to 99%, and particularly preferably 90 to 97%, as described above. When the gel fraction is less than 80%, the durability of the obtained display panel is liable to lower.

Here, the method of measuring the gel fraction of the adhesive is as shown in the test examples described later.

The storage elastic modulus (G') at 85 ° C of the adhesive constituting the first adhesive layer 21 is 0.03 to 0.25 MPa as described above, preferably 0.06 to 0.15 MPa, and particularly preferably 0.08 to 0.10 MPa. When the storage elastic modulus (G') is less than 0.03 MPa, the durability of the obtained display panel is lowered, and when it exceeds 0.25 MPa, the display panel is easily warped under high temperature conditions, and thermal unevenness is likely to occur.

Storage bomb at 85 ° C constituting the adhesive of the second adhesive layer 22 The modulus (G') is 0.15 to 3.00 MPa as described above, preferably 0.20 to 1.00 MPa, and particularly preferably 0.25 to 0.50 MPa. When the storage elastic modulus (G') is less than 0.15 MPa, the adhesion when the second adhesive layer 22 is thinned is insufficient, and when it exceeds 3.00 MPa, the adhesion of the second adhesive layer 22 is obtained. Insufficient, as a result, it is easy to deteriorate durability in any case.

Here, the measuring method of the storage elastic modulus (G') of the adhesive is as shown in the test examples described later.

Further, although not shown, a release sheet may be laminated on the surface (the lower surface in FIG. 1) of the first adhesive layer 21 on the side opposite to the first retardation film 11 side until the adhesive layer is attached. The optical film 1A is used.

1. First phase difference plate

The first retardation film 11 may be composed of a single layer exhibiting a phase difference, or may be composed of a plurality of layers including a phase difference expression layer. The surface of the first retardation film 11 that is in contact with the first adhesive layer 21 is made of an acrylic resin. By using an acrylic resin in the corresponding portion of the first retardation film 11, the first retardation film 11 can be thinned without losing a predetermined optical performance. When the first retardation film 11 is composed of a single layer, the first retardation film 11 is made of a single layer of an acrylic resin. When the first retardation film 11 is composed of a plurality of layers, the outermost layer that is in contact with the first adhesive layer 21 is preferably made of an acrylic resin layer formed by extrusion molding. The acrylic resin has a low adhesion to a conventionally known adhesive layer and has low durability. However, the first adhesive layer 21 according to the present embodiment has high adhesion to the acrylic resin and stress relaxation property. Also excellent. Therefore, it is excellent in durability under high temperature conditions, under moist heat conditions, under thermal shock, and the like. In addition, the "acrylic resin layer formed by extrusion molding" also includes extrusion molding. The acrylic resin layer obtained by extending the treatment.

It is preferable that the first retardation film 11 of the present embodiment has at least an acrylic resin layer and a phase difference expression layer. In particular, as shown in FIG. 2, it is preferable to have the following: a phase difference expression layer 112; The first acrylic resin layer 111 on one surface (the lower surface in FIG. 2) of the phase difference expression layer 112 and the second surface (the upper surface in FIG. 2) laminated on the phase difference expression layer 112 Acrylic resin layer 113. The phase difference expression layer 112 is preferably made of a styrene resin from the viewpoint that the intrinsic birefringence is negative and is easily thinned. Thus, the optical film 1A having the adhesive layer provided on the first retardation film 11 is excellent in viewing angle compensation performance in the liquid crystal display device, particularly in an IPS (In-Place-Switching) mode liquid crystal display device, and the first phase difference is obtained. The plate 11 is configured to include a first acrylic resin layer 111, a phase difference expression layer 112 made of a styrene resin, and a second acrylic resin layer 113. In addition, since the phase difference expression layer 112 is protected by the first acrylic resin layer 111 and the second acrylic resin layer 113 which are present on both surfaces, the optical film 1A with the adhesive layer is not required to lower the phase difference expression layer 112. The performance is excellent in mechanical strength and chemical resistance.

In the first retardation film 11, when the layer in contact with the first adhesive layer 21 is the first acrylic resin layer 111, the adhesion of the first acrylic resin layer 111 to the first retardation film 11 is improved. . Therefore, the optical film 1A with the adhesive layer can be excellent in durability under high temperature conditions, under moist heat conditions, under thermal shock, and the like.

Further, it is preferable that the first retardation film 11 is provided with an in-plane retardation by extension. Thereby, the viewing angle compensation performance is further improved.

The styrene resin constituting the phase difference expression layer 112 may be a homopolymer of styrene or a derivative thereof, or may be a binary or binary copolymer of styrene or a derivative thereof and other copolymerizable monomers. . The styrene derivative refers to a compound in which other groups are bonded to styrene, and examples thereof include o-methylstyrene, m-methylstyrene, p-methylstyrene, and 2,4-. An alkylstyrene such as dimethylstyrene, o-ethylstyrene or p-ethylstyrene, or a hydroxystyrene, a third butoxystyrene, a vinylbenzoic acid, an o-chlorostyrene, A substituted styrene obtained by introducing a hydroxyl group, an alkoxy group, a carboxyl group, a halogen or the like into a benzene nucleus of styrene such as p-chlorostyrene.

As the styrene-based resin, a terpolymer as disclosed in JP-A-2003-50316 or JP-A-2003-207640 can also be used.

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

In addition, as the styrene resin constituting the phase difference expression layer 112, a styrene resin having heat resistance is preferable. The glass transition temperature (Tg) of the styrene resin is generally 100 ° C or higher, but a styrene resin having a glass transition temperature (Tg) of 120 ° C or higher is preferable.

The thickness of the phase difference expression layer 112 is preferably 10 to 100 μm. By making the thickness of the phase difference expression layer 112 10 μm or more, a sufficient retardation value can be expressed by extension. On the other hand, when the thickness of the phase difference expression layer 112 is 100 μm or less, the impact strength is high, and the change in retardation based on the external stress is small, and when it is applied to a liquid crystal display device, it is difficult to cause thermal unevenness.

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

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 alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Further, examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. Such a (meth)acrylic resin can be used as a general-purpose (meth)acrylic resin. Further, the (meth)acrylic resin also includes a material called an impact-resistant (meth)acrylic resin, or a structure having a glutaric anhydride structure or a lactone ring structure in the main chain, which is called high heat resistance (methyl group). ) Acrylic resin.

It is preferred that the rubber particles blended in the (meth)acrylic resin are acrylic. The acrylic rubber particles are rubber-elastic particles obtained by polymerizing an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate as a main component and polymerizing in the presence of a polyfunctional monomer.

The rubber particles may be formed into a homogeneous particle shape by a material having rubber elasticity, or may be a multilayer structure having at least one rubber elastic layer. Examples of the acrylic rubber particles having a multilayer structure include particles having rubber elasticity as described above and having a core surrounded by a hard alkyl methacrylate polymer; and hard methacrylic acid. A base ester polymer is used as a core, and the periphery thereof is coated with an acrylic polymer having rubber elasticity as described above. Further, the periphery of the hard core is covered with a rubber-elastic acrylic polymer, and the periphery thereof is further covered with a hard alkyl methacrylate polymer or the like.

It is preferred that the rubber particles have an average diameter of 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 5 to 100 parts by mass of the (meth)acrylic resin. It is preferably about 50 parts by mass.

The (meth)acrylic resin composition constituting the first acrylic resin layer 111 and the second acrylic resin layer 113 can be used in a state in which a (meth)acrylic resin and acrylic rubber particles are mixed. Examples of commercially available products of a (meth)acrylic resin ((meth)acrylic resin composition) containing acrylic rubber particles are sold under the trade name: Sumitomo Chemical Co., Ltd. "HT55X" or "TechnolloyS001" sold.

The glass transition temperature (Tg) of the (meth)acrylic resin composition is generally 160 ° C or lower, but a (meth)acrylic resin composition having a glass transition temperature (Tg) of 120 ° C or less is preferable, and particularly preferably A (meth)acrylic resin composition of 110 ° C or less. In other words, the glass transition temperature (Tg) of the phase difference expression layer 112 does not overlap with the glass transition temperature (Tg) of the first acrylic resin 111 and the second acrylic resin layer 113, and the phase difference expression layer 112 has a ratio. The glass transition temperature (Tg) of the first acrylic resin layer 111 and the second acrylic resin layer 113 is preferably higher.

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

The thickness of each of the first acrylic resin layer 111 and the second acrylic resin layer 113 is preferably 10 to 100 μm. When the thickness is 10 μm or more, film formation can be easily performed, and when the thickness is 100 μm or less, the retardation of the first acrylic resin layer 111 and the second acrylic resin layer 113 can be ignored. Moreover, it is preferable that the thickness of the first acrylic resin layer 111 is substantially the same as the thickness of the second acrylic resin layer 113.

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

When the first retardation film 11 is produced, for example, a styrene resin and a (meth)acrylic resin composition containing rubber particles may be coextruded and then extended. The extension can be performed by longitudinal uniaxial stretching, tenter lateral uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching, etc., as long as it is extended to obtain a desired retardation value. In addition to the above methods, after separately forming the single-layer film (the phase difference expression layer 112, the first acrylic resin layer 111, and the second acrylic resin layer 113), the heat fusion may be performed by heat lamination. , extending its laminate.

In addition, from the viewpoint of maintaining sufficient performance and meeting the requirements for thinning in mobile communication applications, the total thickness of the first retardation film 11 after stretching is preferably 5 to 100 μm, and more preferably 10 to 50 μm. 15~30μm is especially good.

2. The first adhesive layer

The first adhesive layer 21 may be composed of an adhesive having the above physical properties. It is preferably composed of an acrylic adhesive, and particularly preferably an adhesive obtained from an adhesive composition (hereinafter sometimes referred to as "adhesive composition P"), and the adhesive composition contains an alicyclic ring. a structural monomer (a1) and an aromatic ring-containing monomer (a2) as a (meth) acrylate copolymer (A) constituting a monomer unit of the polymer; and a crosslinking agent (B). Further, in the present specification, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same.

The adhesive agent obtained by containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2) can have appropriate cohesive force and stress relaxation property, and the adhesion to the optical film or the transparent conductive film can be improved. Therefore, when used in a display panel, excellent durability, warpage suppression, and heat unevenness can be exhibited.

(1) (meth) acrylate copolymer (A)

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

Here, the hydroxyl value of the (meth) acrylate copolymer (A) is preferably from 5 to 20 mgKOH/g, more preferably from 8 to 18 mgKOH/g, still more preferably from 10 to 16 mgKOH/g. When the hydroxyl value of the (meth) acrylate copolymer (A) is 5 mgKOH/g or more, the crosslinking point can be secured and a high cohesive force can be maintained, and the storage elastic modulus and gel fraction of the obtained adhesive can be easily obtained. It is designed to be within the range of the above lower limit value. In addition, the (meth) acrylate copolymer (A) When the hydroxyl value is 20 mgKOH/g or less, the crosslinking point is prevented from becoming excessive, and the obtained adhesive is soft, and the storage elastic modulus and the gel fraction are easily designed to be within the range of the upper limit or lower.

Further, the acid value of the (meth) acrylate copolymer (A) is preferably 5 mgKOH/g or less, more preferably 2 mgKOH/g or less, still more preferably 1 mgKOH/g or less. When the acid value of the (meth) acrylate copolymer (A) is 5 mgKOH/g or less, even if the adhesion of the adhesive is caused by an acid, for example, it is transparent such as tin-doped indium oxide (ITO). When a conductive film, a metal film, or the like is used, it is also possible to suppress such a problem due to the generation of acid. In particular, when the attached object is a transparent conductive film, corrosion of the transparent conductive film or a change in resistance value of the transparent conductive film can be suppressed. In addition, the lower limit of the acid value of the (meth) acrylate copolymer (A) is preferably as small as possible, and particularly preferably 0 mgKOH/g.

Here, the hydroxyl value and the acid value in the present specification are basically set to theoretical values derived from the mixing ratio of the (meth) acrylate copolymer (A), and when the theoretical value cannot be derived, it is determined based on JIS K0070. Value.

The (meth) acrylate copolymer (A) contains an alkyl (meth) acrylate having 1 to 20 carbon atoms as an alkyl group constituting the polymer, whereby a good adhesion can be exhibited. . 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, and propyl (meth)acrylate. N-butyl methacrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (methyl) N-decyl acrylate, n-dodecyl (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate, etc. . Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferred, n-butyl (meth)acrylate or 2-ethyl (meth)acrylate. From the viewpoint of improving the glass transition temperature (Tg) of the obtained (meth) acrylate copolymer (A), n-butyl (meth) acrylate is particularly preferable. Further, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A) is preferably an alkyl (meth) acrylate having 1 to 20 carbon atoms and having 40 to 97.5% by mass of an alkyl group as a monomer unit constituting the polymer. It is particularly preferably contained in an amount of 55 to 94% by mass, and more preferably 65 to 83% by mass. When 40% by mass or more of the alkyl (meth)acrylate is contained, the (meth)acrylate copolymer (A) can be provided with an appropriate adhesiveness. In addition, by setting the alkyl (meth)acrylate to 97.5% by mass or less, it is possible to introduce a desired amount of other monomer components into the (meth) acrylate copolymer (A).

The carbon ring of the alicyclic structure of the alicyclic structural monomer (a1) may be a saturated structure or a partially unsaturated bond. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. The distance between the obtained (meth) acrylate copolymers (A) is appropriately set, and the adhesive stress relaxation property is imparted, and the obtained (meth) acrylate copolymer is obtained by lifting ( The glass transition temperature (Tg) of A) is preferable from the viewpoint of improving the adhesion to the acrylic resin, and the alicyclic structure is a polycyclic alicyclic structure (polycyclic structure). Further considering the compatibility of the (meth) acrylate copolymer (A) with other components, the above polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, from the same as above From the viewpoint of imparting stress relaxation and raising the glass transition temperature (Tg) of the obtained (meth) acrylate copolymer (A), the number of carbon atoms of the alicyclic structure (refers to all of the portions forming the ring) When the number of carbon atoms is plural, the total number of carbon atoms is usually 5 or more, and preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms of the alicyclic structure is not particularly limited, but similarly to the above, from the viewpoint of compatibility, 15 or less is preferable, and 10 or less is particularly preferable.

Examples of the alicyclic structure include those having a skeleton, a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isobornyl skeleton, a cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, or cyclic anthracene). Alkane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloolefin skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubic An alkane skeleton, a snail skeleton, an alkane skeleton, a spiro skeleton, or the like, which contains a dicyclopentadiene skeleton (an alicyclic structure having 10 carbon atoms: 10) and an adamantane skeleton (for an alicyclic structure: 10) The number of carbon atoms of the alicyclic structure: 10) or the isobornyl skeleton (the number of carbon atoms of the alicyclic structure: 7) is preferable, and particularly preferably the one containing the isobornyl skeleton.

As the alicyclic structure-containing monomer (a1), a (meth) acrylate monomer having the above skeleton is preferable, and specific examples thereof include cyclohexyl (meth) acrylate and (meth) acrylate. Dicyclopentyl ester, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. It is preferable to use dicyclopentyl (meth)acrylate, amantadine (meth)acrylate or isobornyl (meth)acrylate, which is excellent in durability, and particularly preferably (meth)acrylic acid. Isobornyl ester, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A) contains an alicyclic structure containing 1 to 20% by mass from the viewpoint of exhibiting excellent durability, warpage inhibition property, and heat unevenness of the obtained adhesive. The monomer (a1) is preferred as the monomer unit constituting the polymer. In addition to the above viewpoints, from the viewpoint of exhibiting good reprocessability of the obtained adhesive, in particular, the alicyclic structure-containing monomer (a1) containing 2 to 15% by mass is more preferable, and contains 3~ 9% by mass is particularly good.

As the aromatic ring-containing monomer (a2), a (meth) acrylate having an aromatic ring is preferred. The aromatic ring may, for example, be a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring or an anthracene ring, and a benzene ring is preferred.

Examples of the aromatic ring-containing monomer (a2) include phenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, benzyl (meth)acrylate, and naphthyl (meth)acrylate. Phenyloxyethyl (meth)acrylate, phenoxybutyl (meth)acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth) acrylate, epoxy B Alkyl modified cresol (meth) acrylate, ethylene oxide (EO) modified nonyl phenol (meth) acrylate, etc., wherein 2-benzyl (meth) acrylate is used from the viewpoint of improving cohesion A phenyl group is preferred. These may be used singly or in combination of two or more.

The (meth) acrylate copolymer (A) is preferably one or more than 30% by mass of the aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer, and more preferably 3 to 25% by mass. More preferably, it contains 12-22 mass %. By setting the content of the aromatic ring-containing monomer (a2) within the above range, the obtained adhesive can exhibit excellent durability, warpage inhibition property, and heat unevenness.

The (meth) acrylate copolymer (A) preferably contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer. The hydroxyl group shows good reactivity with the crosslinking agent (B), and by their reaction, the (meth) acrylate copolymer (A) is crosslinked by the crosslinking agent (B). Due to the crosslinked structure, the obtained adhesive easily satisfies the aforementioned storage elastic modulus and gel fraction.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (methyl). a hydroxyalkyl (meth) acrylate such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate, and the like, and a crosslinking agent (B) From the viewpoint of reactivity, 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is particularly preferred. These may be used singly or in combination of two or more.

The (meth) acrylate copolymer (A) preferably contains 0.5 to 10% by mass of the hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, more preferably 1 to 5% by mass, further It is preferably contained in an amount of 2 to 4% by mass. By setting the content of the hydroxyl group-containing monomer (a3) within the above range, the hydroxyl value of the (meth) acrylate copolymer (A) can be easily dropped within the above range, and the storage elastic modulus and the storage elastic modulus can be easily satisfied. Gel fraction.

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

The (meth) acrylate copolymer (A) may also contain the aforementioned monomer Other monomers other than the monomer unit constituting the polymer. In order not to hinder the reaction of the hydroxyl group of the hydroxyl group-containing monomer (a3) with the crosslinking agent (B), a monomer which does not contain a functional group reactive with the crosslinking agent (B) is preferably used as the other monomer. .

Examples of the other monomer include a (meth)acrylic acid alkoxyalkyl ester such as methoxyethyl (meth)acrylate or ethoxyethyl (meth)acrylate; acrylamide; Non-crosslinkable acrylamide such as acrylamide; N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. A crosslinkable tertiary amino group (meth) acrylate; vinyl acetate or the like. These may be used singly or in combination of two or more.

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

The weight average molecular weight of the (meth) acrylate copolymer (A) is preferably from 1.3 to 3,000,000, particularly 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) acrylate copolymer (A) is 1.3 million or more, it is easy to design the storage elastic modulus and the gel fraction of the obtained adhesive to be equal to or higher than the above lower limit value, and it is possible to satisfactorily Ensure durability. When the weight average molecular weight of the (meth) acrylate copolymer (A) is 3,000,000 or less, it is easy to design the storage elastic modulus and the gel fraction of the obtained adhesive to be equal to or less than the above upper limit value, which is good. The stress relaxation property is ensured, and the warpage suppression property and the heat resistance unevenness can be effectively exhibited.

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

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

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

(2) Crosslinking agent (B)

The crosslinking agent (B) may be reacted with a functional group of the (meth) acrylate copolymer (A), and examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, and an amine. Crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxy crosslinking agent, metal chelate An organic crosslinking agent, a metal salt crosslinking agent, an ammonium salt crosslinking agent, and the like.

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

The isocyanate crosslinking agent is a compound containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone II. Alicyclic polyisocyanate such as isocyanate or hydrogenated diphenylmethane diisocyanate Ester, in addition to such biuret, isocyanurate, further with ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil and other low molecular activity An adduct of a reactant of a hydrogen compound (hereinafter referred to collectively as "modified body"). Among these, from the viewpoint of the durability of the obtained adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified form thereof is preferred, and has an organic group (for example, A polyisocyanate which is preferably an alkylene chain, particularly preferably an alkylene chain having 1 to 4 carbon atoms and an isocyanate group bonded to an aromatic ring, or a modified form thereof is particularly preferred. Specifically, xylylene diisocyanate or a modified form thereof is further preferred, and trimethylolpropane modified xylylene diisocyanate is preferred. These isocyanate type crosslinking agents may be used alone or in combination of two or more.

The content of the crosslinking agent (B) in the adhesive composition P is preferably 0.01 to 10 parts by mass, particularly preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). Further preferably, it is 0.1 to 0.4 parts by mass. By setting the content of the crosslinking agent (B) within the above range, it is easy to design the storage elastic modulus and the gel fraction of the obtained adhesive to be within the above range.

(3) decane coupling agent (C)

The adhesive composition P preferably contains a decane coupling agent (C) in addition to the above (meth) acrylate copolymer (A) and the crosslinking agent (B), and is excellent in imparting the obtained adhesive. From the viewpoint of durability, it is particularly preferable to contain an epoxy group-containing decane coupling agent (C1) and/or a decyl decane coupling agent (C2), and further preferably an epoxy group-containing decane coupling agent (C1) and Both of the mercaptodecane coupling agents (C2) are contained.

Suitable as an epoxy-containing decane coupling agent (C1), molecule An organic ruthenium compound having at least one epoxy group (epoxy group-containing organic group) and at least one alkoxy decyl group, and having good compatibility with an adhesive component and having light transmissivity, for example, substantially transparent By.

Specific examples of the epoxy group-containing decane coupling agent (C1) include 3-glycidol such as 3-glycidoxypropyltrimethoxydecane or 3-glycidoxypropyltriethoxysilane. Oxypropylpropylalkoxydecane; 3-glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropylmethyldimethoxydecane, etc. 3-glycidoxypropyl Alkyl dialkoxy decane; methyl tris(glycidyl) decane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 2-(3,4-epoxycyclohexyl 2-(3,4-epoxycyclohexyl)ethyltrialkoxydecane, etc., such as ethyltriethoxydecane. Among them, from the viewpoint of further improving durability, 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, 3-glycidoxypropylmethyldi Ethoxy decane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxynonane is preferred, and 3-glycidoxypropyltrimethoxydecane is particularly preferred. These may be used alone or in combination of two or more.

Suitable as a mercapto-containing decane coupling agent (C2), an organic antimony compound having at least one mercapto group (an organic group containing a mercapto group) and at least one alkoxyalkyl group in the molecule, and having good compatibility with an adhesive component and Those having light transmissivity, for example, are substantially transparent.

Specific examples of the mercapto-containing decane coupling agent (C2) include 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, and 3-mercaptopropyldimethoxymethylnonane. a fluorenyl-containing low molecular type decane coupling agent; and a decyl decane-containing compound (for example, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyl group) Triethoxy decane, 3-mercaptopropyl dimethoxymethyl decane, etc.) and alkyl decane-containing compounds (eg, methyl triethoxy decane, ethyl triethoxy decane, methyl trimethoxy decane) A mercapto group-containing oligomer or a decane coupling agent such as a cocondensate such as ethyltrimethoxydecane. Among them, a fluorenyl group-containing oligomer-type decane coupling agent is preferred from the viewpoint of achieving both durability and reworkability, and particularly preferably a cocondensate of a decyl decane compound and an alkyl decane-containing compound, further preferably a cocondensate of 3-mercaptopropyltrimethoxydecane with methyltriethoxydecane. These may be used alone or in combination of two or more.

As the decane coupling agent (C), in addition to the above-mentioned epoxy group-containing decane coupling agent (C1) and a mercapto-containing decane coupling agent (C2), for example, an acrylonitrile-based decane coupling agent or a hydroxy-based decane coupling may be used as needed. A mixture, a carboxy-based decane coupling agent, an amine-based decane coupling agent, a guanamine-based decane coupling agent, an isocyanate-based decane coupling agent, and the like.

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

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

(4) Antistatic agent (D)

The adhesive composition P further preferably contains an antistatic agent (D). The optical film (first retardation film 11) or the release sheet laminated on the first adhesive layer 21 is usually made of a plastic material, and therefore has high electrical insulating properties, such as static electricity easily generated when the release sheet is peeled off. When the optical film is adhered to the liquid crystal cell in a state in which the static electricity generated is left, the alignment of the liquid crystal molecules may be disturbed, and the presence of static electricity may cause problems such as the attraction of flying dust or dust. Therefore, the adhesive composition P contains the antistatic agent (D), and the obtained adhesive (the first adhesive layer 21) can exhibit antistatic properties, thereby eliminating the above problems.

The antistatic agent (D) is not particularly limited as long as it can provide the antistatic property of the obtained adhesive, and examples thereof include an ionic compound and a nonionic compound. Among them, an ionic compound is preferred. The ionic compound may be a liquid or a solid at room temperature, but is preferably solid at room temperature from the viewpoint of easily exhibiting stable antistatic properties even when exposed to endurance conditions. Here, the ionic compound in the present specification means a compound mainly composed of a cation and an anion and bonded by electrostatic attraction.

As the ionic compound, a nitrogen-containing phosphonium salt, a sulfur-containing phosphonium salt, a phosphorus-containing phosphonium salt, an alkali metal salt, and an alkaline earth metal salt are preferable, and from the viewpoint of excellent durability of the obtained adhesive, it is particularly preferable. Nitrogen-containing barium salt. The nitrogen-containing phosphonium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a counter anion thereof, particularly preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion, and more preferably at room temperature. The following is an ionic compound which is solid and consists of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion. According to an ionic compound which is solid at room temperature and consists of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion, Antistatic and durability.

As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, an anthracene ring or the like is preferable, and a pyridine ring is preferred. Further, as the halogen of the halogenated phosphoric acid anion, fluorine, chlorine, bromine or the like is preferable, and among them, fluorine is preferred.

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, and N-octyl group. Pyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N - cetylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4-methylpyridinium hexafluorophosphate, N- Cetyl-4-methylpyridinium hexafluorophosphate and the like. Among these, from the viewpoint of compatibility with the (meth) acrylate copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methyl Pyridinium hexafluorophosphate and N-octyl-4-methylpyridinium hexafluorophosphate are preferred. The above antistatic agents (D) may be used alone or in combination of two or more.

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

(5) Various additives

Various additives generally used for the acrylic adhesive may be added to the adhesive composition P as needed, for example, a dispersing agent (for example, an alkylene glycol) may be added. Dialkyl ether), tackifier, antioxidant, ultraviolet absorber, light stabilizer, softener, filler, refractive index modifier, and the like. In addition, the adhesive composition P is a component which is a mixture of various components remaining in the adhesive layer as it is or in a state of being reacted, and is removed in a drying process or the like, for example, a polymerization solvent or a diluent solvent to be described later. It is not included in the adhesive composition P.

(6) Method for producing adhesive composition

The adhesive composition P can be produced by producing a (meth) acrylate copolymer (A), and the obtained (meth) acrylate copolymer (A) and a crosslinking agent (B), as needed The obtained decane coupling agent (C), an antistatic agent (D), an additive, and the like are mixed and produced.

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

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more kinds thereof may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis (cyclohexane). Alkan 1-nitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile ), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2- Hydroxymethylpropionitrile, 2,2'-azobis[2-(2-imidazolin-2-yl)propane, and the like.

Examples of the organic peroxide include benzoic acid peroxide. Tert-butyl benzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-(2-ethoxyethyl) peroxydicarbonate , peroxy neodymium tert-butyl ester, peroxypivalic acid tert-butyl ester, (3,5,5-trimethylhexyl) peroxide, dipropyl decyl peroxide, diethyl hydrazino Peroxide and the like.

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

After obtaining the (meth) acrylate copolymer (A), a crosslinking agent (B) is added to the solution of the (meth) acrylate copolymer (A), and a decane coupling agent (C) is added as needed, and antistatic is carried out. The agent (D), an additive, a diluent solvent, and the like are sufficiently mixed, whereby an adhesive composition P (coating solution) diluted with a solvent is obtained.

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

The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they are within the coatable range, and may be appropriately selected depending on the case. For example, the concentration of the adhesive composition P is diluted to 10 to 40% by mass. In addition, when the coating solution is obtained, the addition of the diluent solvent or the like is not a requirement, and the viscosity of the adhesive composition P may be such that the viscosity of the coating composition P can be applied without adding a diluent solvent. In this case, the adhesive composition P becomes (meth)acrylic acid. The polymerization solvent of the ester copolymer (A) is directly used as a coating solution of a diluent solvent.

(7) Adhesive

In the present embodiment, the adhesive constituting the first adhesive layer 21 is obtained from the adhesive composition P described above. Specifically, the adhesive composition P is crosslinked. The crosslinking of the adhesive composition P can be carried out by heat treatment. In addition, the drying treatment at the time of volatilization of the dilution solvent of the adhesive composition P may be used as the heat treatment.

When the heat treatment is performed, the heating temperature is preferably from 50 to 150 ° C, particularly preferably from 70 to 120 ° C. Further, the heating time is preferably from 30 seconds to 10 minutes, and particularly preferably from 50 seconds to 2 minutes. After the heat treatment, a curing period of about 1 to 2 weeks under normal temperature (for example, 23 ° C, 50% RH) may be set as needed. When the curing period is required, when the adhesive layer having a predetermined physical property is formed after the curing period, and the curing period is not required, the adhesive layer is formed after the heat treatment is completed.

According to the above heat treatment (and curing), the (meth) acrylate copolymer (A) is crosslinked by the crosslinking agent (B) to form a three-dimensional network structure. The degree of crosslinking of the adhesive obtained by such crosslinking, that is, the gel fraction is within the above range.

(8) Physical properties of the first adhesive layer

The thickness of the first adhesive layer 21 is preferably 5 to 100 μm, more preferably 10 to 60 μm, particularly preferably 10 to 50 μm, and further preferably 15 to 30 μm. When the thickness of the first adhesive layer 21 is within the above range, the effect of the gel fraction and the storage elastic modulus of the adhesive constituting the first adhesive layer 21 can be effectively exhibited, that is, excellent durability. , warpage inhibition and heat unevenness.

The haze value of the first adhesive layer 21 (according to JIS K7136:2000) The value of the measurement is preferably 2% or less, and particularly preferably 1% or less. When the haze value is 2% or less, the transparency is very high, and it is suitable as an optical user.

3. 2nd adhesive layer

The second adhesive layer 22 may be formed of an adhesive having the above physical properties, and may be a curable adhesive or a non-curable adhesive. However, in order to set the storage elastic modulus and the gel fraction. In the above range, it is preferred to use an active energy ray-curable adhesive.

The active energy ray-curable adhesive may be a polymer having active energy ray-curable polymer as a main component, or a polymer having no active energy ray-curable polymer and active energy ray-curable polyfunctional monomer and / or a mixture of oligomers as a main component. Further, it may be a mixture of a polymer having active energy ray hardenability and a polymer having no active energy ray hardening property, or a polymer having active energy ray hardenability and an active energy ray hardening polyfunctional monomer. And/or a mixture of oligomers, which may also be a mixture of the three.

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

As a polymer having no active energy ray-curable property, a (meth) acrylate polymer (hereinafter referred to as "(meth) acrylate polymer (X)") having no active energy ray-curable group is comparatively good. (Methacrylate The ester polymer (X) is preferably a (meth)acrylic acid alkyl ester having an alkyl group and having 1 to 20 carbon atoms as a monomer constituting the polymer. Thereby, the obtained adhesive can exhibit better adhesion. Further, the (meth) acrylate polymer (X) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, and a monomer having a reactive functional group (containing a reactive functional group). Copolymers, and copolymers of other monomers used as needed are particularly preferred. When the (meth) acrylate polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, adhesion to a glass surface of a liquid crystal cell or the like can be improved, and It reacts with the crosslinking agent (Z) mentioned later, and forms a bridge|crosslinking 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, and propyl (meth)acrylate. N-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (methyl) N-decyl acrylate, n-dodecyl (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate Wait. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferred, and n-butyl (meth) acrylate is particularly preferred. Further, these may be used alone or in combination of two or more.

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

As the reactive functional group-containing monomer, a molecule is preferably exemplified A monomer having a hydroxyl group (hydroxyl-containing monomer), a monomer having a carboxyl group in the molecule (a carboxyl group-containing monomer), a monomer having an amine group in the molecule (an amine group-containing monomer), and the like. These reactive functional group-containing monomers may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-(meth)acrylate. A hydroxyalkyl (meth)acrylate such as hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate or 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 preferred from the viewpoint of reactivity between the carboxyl group of the obtained (meth)acrylate polymer (X) and the crosslinking agent (Z) and copolymerization with other monomers. These may be used singly or in combination of two or more.

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

The (meth) acrylate polymer (X) is preferably a monomer having a reactive functional group containing 1 to 25% by mass as a monomer unit constituting the polymer, particularly preferably 1 to 20% by mass, further It is preferably contained in an amount of 2 to 5% by mass.

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

The (meth) acrylate polymer (X) preferably has a weight average molecular weight of 300,000 to 3,000,000, more preferably 1,000,000 to 2,500, and further preferably. It is 1.6 million to 2.2 million.

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

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

Examples of the polyfunctional acrylate monomer having a molecular weight of 1,000 or less include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentane. Diol (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxy trimethyl acetic acid neopentyl glycol di (a) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, a bifunctional type such as bis(propyleneoxyethyl)isocyanurate or allylated cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri Methyl) acrylate, propionic acid modified dipentaerythritol tri(meth) acrylate, pentaerythritol tri-(meth) acrylate, propylene oxide modified trimethylolpropane tri(meth) acrylate, three ( 3-functional type such as acryloxyethyl)isocyanurate or ε-caprolactone modified tris(2-(methyl)propenyloxyethyl)isocyanurate; diglycerol tetra(A) Acrylate a tetrafunctional type such as an alcohol tetra(meth)acrylate; a 5-functional type such as propionic acid modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa(meth) acrylate; caprolactone modified dipentaerythritol hexa A 6-functional type such as a methyl acrylate or the like. These may be used alone or in combination of two or more.

The content of the active energy ray-curable compound (Y) is preferably from 1 to 50 parts by mass, particularly preferably from 5 to 30 parts by mass, based on 100 parts by mass of the (meth) acrylate polymer (X). It is 10 to 20 parts by mass.

The active energy ray-curable adhesive preferably contains a crosslinking agent (Z). When the adhesive contains a (meth) acrylate polymer (X) containing a reactive functional group-containing monomer and a crosslinking agent (Z) as a monomer unit constituting the polymer, if the adhesive is heated or the like, The crosslinking agent (Z) is reacted with a reactive functional group of the reactive functional group-containing monomer constituting the (meth) acrylate polymer (X). Thereby, the structure in which the (meth) acrylate polymer (X) is crosslinked by the crosslinking agent (Z) is formed, the cohesive force of the obtained adhesive is improved, and the obtained adhesive easily satisfies the aforementioned storage elastic modulus. And gel fraction.

The crosslinking agent (Z) may be reacted with a reactive functional group of the (meth) acrylate polymer (X), and examples thereof include an isocyanate crosslinking agent and an epoxy crosslinking agent. An amine crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent, an anthraquinone crosslinking agent, an aldehyde crosslinking agent, an oxazoline crosslinking agent, a metal alkoxide crosslinking agent, and a metal chelate A compound-based crosslinking agent, a metal salt-based crosslinking agent, an ammonium salt-based crosslinking agent, and the like. As the isocyanate crosslinking agent, the same as the above crosslinking agent (B) can be used. Further, the crosslinking agent (Z) may be used alone or in combination of two or more.

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

The active energy ray-curable adhesive may contain various additives as needed, for example, a photopolymerization initiator, a decane coupling agent, and a refractive index adjustment. Whole agent, antistatic agent, tackifier, antioxidant, ultraviolet absorber, light stabilizer, softener, filler, etc.

When ultraviolet rays are used as the active energy ray for curing the active energy ray-curable adhesive, it is preferred that the active energy ray-curable adhesive 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, dimethylamino acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1 -ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4-(2-hydroxyethyl) Oxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichloroethylene Benzophenone, 2-methylindole, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethyl ketal, p-dimethyl Amino benzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzhydrazide Base-diphenyl-phosphine oxide and the like. These may be used singly or in combination of two or more.

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

Further, from the viewpoint of improving the adhesion of the obtained adhesive to the film, the active energy ray-curable adhesive contains a decane coupling agent. good. The decane coupling agent is an organic ruthenium compound having at least one alkoxyalkyl group in the molecule, and is preferably compatible with an adhesive component and has light transmissibility.

As the decane coupling agent, for example, in addition to the epoxy group-containing decane coupling agent (C1) and the fluorenyl decane-containing coupling agent (C2), a polymerizable unsaturated hydrazine-containing compound (for example, vinyltrimethoxy) may be mentioned. Alkyl decane, vinyl triethoxy decane, methacryloxypropyl trimethoxy decane, etc., an amine group-containing hydrazine compound (for example, 3-aminopropyltrimethoxydecane, N-(2-amine) Benzyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, etc., 3-chloropropyltrimethoxy A decyl alkane, a 3-isocyanate propyl triethoxy decane, or at least one of these, and an alkyl-containing hydrazine compound (eg, methyl triethoxy decane, ethyl triethoxy decane, methyl trimethyl a condensate of oxydecane, ethyltrimethoxydecane, or the like. These may be used alone or in combination of two or more.

The content of the decane coupling agent is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, even more preferably 0.1 to 1 part by mass, per 100 parts by mass of the (meth) acrylate polymer (X). .

Further, the polymer having the active energy ray-curable property is a (meth) acrylate (co)polymer having a functional group (active energy ray-curable group) having an active energy ray-curable property introduced into a side chain. good.

The thickness of the second adhesive layer 22 is preferably 1 to 50 μm, more preferably 1 to 20 μm, and particularly preferably 2 to 7 μm. When the adhesive constituting the second adhesive layer 22 has the storage elastic modulus and the gel fraction, even when the thickness of the second adhesive layer 22 is reduced to the above range, it is possible to ensure sufficient The adhesion. Further, by thinning the second adhesive layer 22 as described above, the loss of optical characteristics of the second adhesive layer 22 can be minimized.

4. Second phase difference plate

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

Among them, as the olefin-based resin, a resin mainly containing a structural unit derived from an alicyclic olefin, that is, a cyclic olefin-based resin can be preferably used. When the second retardation film 12 is made of a cyclic olefin resin, the change in optical characteristics of the second retardation film 12 under endurance conditions can be suppressed to be small.

Typical examples of the alicyclic olefin constituting the cyclic olefin resin include a norbornene-based monomer. Norbornene refers to a compound in which a carbon-carbon bond of norbornane is a double bond, and is named as bicyclo [2,2,1]hept-2-ene according to the IUPAC nomenclature. Examples of the substituent of norbornene include a 3-substituent, a 4-substituted compound, a 4,5-disubstituted product, etc., when the position of the double bond of the norbornene is 1,2-position. Further, dicyclopentadiene or dimethicone may be used as a monomer constituting the cyclic olefin resin.

The cyclic olefin-based resin may or may not have a norbornane ring in its structural unit. The norbornene-based monomer which is a cyclic olefin-based resin which does not have a norbornane ring in the structural unit, for example, may be a ring-opening ring, and may be exemplified by norbornene or bicyclic ring. Pentadiene, 1- or 4-methylnorbornene, 4-phenylnorbornene, and the like. When the cyclic olefin resin is a copolymer, The arrangement state 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 a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer, and the like. A polymer modified product obtained by acid addition or cyclopentadiene addition, or a polymer or copolymer obtained by hydrogenating the same, an addition polymer of a norbornene-based monomer, and a norbornene-based single Addition copolymer of a body and other monomers, and the like. Examples of the other monomer in the case of the copolymer include an α-olefin, a cycloolefin, and a non-conjugated diene. Further, the cyclic olefin resin may be a copolymer in which one or two or more kinds of norbornene-based monomers and other alicyclic olefins are used.

In the above specific example, as the cyclic olefin resin, a resin obtained by hydrogenating a ring-opening polymer using a norbornene monomer can be preferably used. Such a cyclic olefin-based resin can be formed into a retardation film by stretching treatment, and can be subjected to heat shrinkage treatment by stretching and shrinking a shrinkable film having a predetermined shrinkage ratio, thereby having high uniformity and having A phase difference plate with a large phase difference.

Commercial products (all trade names) of a cyclic olefin-based resin using a norbornene-based monomer, "ZEONEX" and "ZEONOR" sold by Zeon Corporation, and "ARTON" sold by JSR CORPORATION Wait. The film of the cyclic olefin-based resin or the stretched film thereof can be obtained from commercially available products, for example, (both trade names), "ZEONOR film" sold by Zeon Corporation, and "ARTON film" sold by JSR CORPORATION. "ESSINA" sold by SEKISUI CHEMICAL CO., LTD.

In addition, the second retardation film 12 may be a film made of a mixed resin containing two or more kinds of olefin resins or a film made of a mixed resin of an olefin resin and another thermoplastic resin. For example, a mixed resin containing two or more kinds of olefin-based resins may be a mixture of the above-described cyclic olefin-based resin and a chain aliphatic olefin-based resin. When a mixed resin of an olefin-based resin and another thermoplastic resin is used, other thermoplastic resins can be appropriately selected depending on the purpose. Specific examples thereof include a polyvinyl chloride resin, a cellulose resin, a polystyrene resin, an acrylonitrile/butadiene/styrene copolymer resin, an acrylonitrile/styrene copolymer resin, and (methyl group). Acrylic resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamine resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polyparaphenylene Butyl formate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polyfluorene resin, polyether oxime resin, polyether ether ketone resin, polyarylate resin, liquid crystal A resin, a polyamidoximine resin, a polyimide resin, a polytetrafluoroethylene resin, or the like. The thermoplastic resin may be used alone or in combination of two or more. Further, the above thermoplastic resin may be used after any appropriate polymer modification. Examples of the modification of the polymer include copolymerization, crosslinking, modification of the molecular terminal, and stereoregularity.

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% by mass or less, and about 40% by mass or less, based on the total of all the resins. By setting the content of the other thermoplastic resin within this range, it is possible to obtain a phase difference plate having a small absolute value of the photoelastic coefficient and excellent wavelength dispersion characteristics, and excellent in durability, mechanical strength, and transparency.

The olefin resin can be formed into a film by a casting method of a solution or a melt extrusion method. When a film is formed by using two or more kinds of mixed resins, the film forming method is not particularly limited. For example, a uniform solution obtained by stirring and mixing a resin component together with a solvent in a predetermined ratio may be used and a film may be produced by a casting method. A method of melt-mixing a resin component in a predetermined ratio, a method of producing a film by melt extrusion, and the like.

The film made of the above olefin-based resin may contain a residual solvent, a stabilizer, a plasticizer, an anti-aging agent, an antistatic agent, an ultraviolet absorber, etc., and may contain other components as needed. In addition, a leveling agent may also be included to reduce the surface roughness.

The surface of the second phase difference plate 12 on the side of the second adhesive layer 22 may be subjected to a surface treatment such as corona treatment.

It is preferable that the second retardation film 12 has refractive index anisotropy which satisfies the following conditions, and sets the refractive indices in the in-plane slow axis direction, the in-plane fast axis direction, and the thickness direction to n _x , respectively. n _y and n _z , and when the thickness of the film is d, the in-plane retardation at a wavelength of 590 nm defined by the following formula (1): R _e = (n _{x -} n _y ) × d (1) The value R _e is 30 to 150 nm, and the Nz coefficient defined by the following formula (2): Nz coefficient = (n _{x -} n _z ) / (n _{x -} n _y ) (2) exceeds 1, and is less than 2.

The second retardation film 12 having the refractive index anisotropy as described above can be longitudinally uniaxially stretched by a film made of the above olefin resin, laterally uniaxially stretched by a tenter, simultaneously biaxially stretched or successively biaxially Extend and wait for it, and The desired refractive index anisotropy can be obtained by appropriately adjusting the stretching ratio and the stretching speed, or suitably selecting various temperatures and patterns of the preheating temperature, the stretching temperature, the thermosetting temperature, the cooling temperature, and the like at the time of stretching. .

The second retardation film 12 is preferably in the range of 5 to 80 μm, more preferably in the range of 10 to 80 μm, and particularly preferably in the range of 10 to 30 μm.

5. Method for producing an optical film with an adhesive layer

A preferred embodiment of the method for producing the optical film 1A with the adhesive layer will be described.

(1) Fabrication of phase difference plate laminate

First, a phase difference plate laminate comprising the first retardation film 11, the second adhesive layer 22, and the second retardation film 12 is produced. The production of the phase difference plate laminate can be carried out by a usual method.

For example, a coating film of the adhesive constituting the second adhesive layer 22 is formed on the peeling surface of the release sheet. Specifically, the coating liquid of the adhesive constituting the second adhesive layer 22 is applied onto the release surface of the release sheet and dried. The description of the release sheet will be described later.

As a method of applying the above 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, or the like can be used.

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

Next, the second phase difference plate 12 is bonded to form the above-mentioned release sheet. The coating film of the adhesive of the second adhesive layer 22 thereon. Then, the active energy ray is irradiated through the release sheet to cure the coating film of the adhesive, and the coating film is used as the second adhesive layer 22.

Here, the active energy ray means an energy quantum in an electromagnetic wave or a charged particle beam, and specifically, an ultraviolet ray or an electron beam is mentioned. Among the active energy rays, ultraviolet rays that are easy to handle are particularly excellent.

The irradiation of ultraviolet rays can be carried out by a high pressure mercury lamp, a metal halide lamp, a molten H lamp, a xenon lamp or the like, and the irradiation amount of the ultraviolet rays is preferably about 50 to 1000 mW/cm ² . Further, the light amount is preferably from 50 to 10,000 mJ/cm ² , more preferably from 80 to 5,000 mJ/cm ² , particularly preferably from 100 to 1,000 mJ/cm ² . On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

After that, the release sheet is peeled off from the second adhesive layer 22 formed as described above, and the surface of the first retardation film 11 on the second acrylic resin layer 113 side is bonded to the exposed second adhesive layer 22 . . Thereby, a phase difference plate laminate (optical film) in which the second retardation film 12, the second adhesive layer 22, and the first retardation film 11 are laminated is obtained.

Further, the total thickness of the phase difference plate laminate is preferably 15 to 200 μm, more preferably 25 to 150 μm, and particularly preferably 30 to 65 μm.

(2) Manufacture of the adhesive sheet of the first adhesive layer

An adhesive sheet produced by laminating a release sheet on one or both sides of an adhesive layer formed of the adhesive composition P. Here, as an example, an adhesive sheet in which a release sheet is laminated on both surfaces of an adhesive layer is used.

As the release sheet, for example, a polyethylene film, a polypropylene film, or the like can be used. Polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, poly pair Butylene phthalate film, polyurethane film, ethylene vinyl acetate film, ionic polymer resin film, ethylene-(meth)acrylic copolymer film, ethylene-(meth)acrylate copolymer film , polystyrene film, polycarbonate film, polyimide film, fluororesin film, and the like. In addition, such crosslinked films can also be used. It may also be such a laminated film.

It is preferred to carry out a release treatment on at least one side of the release sheet (particularly, a release surface that is in contact with the adhesive layer). Examples of the release agent used in the release treatment include an alkyd type, an anthrone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type release agent. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property on the peeling sheet, and the surface which carried out the peeling process, and the surface which shows the peeling-re-

When a release sheet is laminated on both surfaces of the adhesive layer, one of the release sheets is used as a heavy release release sheet having a large peeling force, and the other release sheet is used as a light release type release sheet having a small peeling force. good.

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

As an example of the method for producing the pressure-sensitive adhesive sheet, a coating solution of the adhesive composition P is applied onto the release surface of the release sheet, and after heat treatment to form a coating film, if necessary, another release sheet is laminated on the coating film. (in the manner in which the peeling surface is in contact with the coating film) or the substrate. When the coating film does not require a curing period, the first adhesive layer 21 is directly formed, and when the curing period is required, the first adhesive layer 21 is formed after the curing period. Conditions for heat treatment and curing, such as The foregoing.

As a method of applying the above 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, or the like can be used.

(3) Manufacture of optical film with adhesive layer

The release sheet (light-peelable release sheet) on one side was peeled off from the adhesive sheet obtained as described above. Then, the first acrylic resin layer 111 of the first retardation film 11 of the retardation laminate is superposed on the exposed adhesive layer, and the adhesive sheet and the retardation laminate are pressed. Thereby, the optical film 1A (with a release sheet) with the above-mentioned adhesive layer was obtained.

In another example of the method for producing the optical film 1A with the adhesive layer, a solution (coating solution) containing the adhesive composition P is applied onto the release surface of the release sheet, and after heat treatment to form a coating film, The first acrylic resin layer 111 of the first retardation film 11 of the phase difference plate laminate is superposed on the coating film. When the coating film requires a curing period, the first adhesive layer 21 is formed by the interval curing period, and when the curing period is not required, the first adhesive layer 21 is directly formed. Thereby, the optical film 1A (with a release sheet) with the above-mentioned adhesive layer was obtained.

6. Physical properties of optical films with adhesive layers

The adhesive force of the optical film 1A with the adhesive layer of the present embodiment is preferably 0.5 to 20 N/25 mm, and particularly preferably 1 to 10 N/25 mm for the adhesion of the alkali-free glass. Thereby, the optical film 1A with an adhesive layer is excellent in durability. Further, from the viewpoint of excellent reworkability, the adhesion is preferably 2 to 7 N/25 mm. In addition, the adhesive force referred to herein means an adhesive force which is basically measured in accordance with JIS Z0237:2009 by the 180° peeling method, and is set to The measurement sample was set to have a width of 25 mm and a length of 100 mm, and the measurement sample was pressed at 0.5 MPa, 50 ° C for 20 minutes, and attached to the subject, and then under normal pressure, 23 ° C, and 50% RH. After standing for 24 hours, the measurement was carried out at a peeling speed of 300 mm/min. When the adhesion is within the above range and adhered to the liquid crystal cell, warpage, surface peeling, or the like can be prevented.

Further, the optical film 1A with the adhesive layer of the present embodiment adhered to the above-mentioned subject and further adhered to the adhesive body at 23 ° C and 50% RH for 14 days (after 14 days of attachment) The adhesion is preferably 1~20N/25mm, and the best is 3~9N/25mm. By suppressing the improvement of the adhesive force with the passage of time, the optical film 1A with the adhesive layer of the present embodiment is excellent in reworkability, and can be easily reattached after being attached to the liquid crystal cell.

In addition, the optical film 1A with the adhesive layer of the present embodiment adhered to the above-mentioned subject and adhered to the subject at 50 ° C and 50% RH for 2 days (adhesive force at 50 ° C 2 From the viewpoint of durability, from the viewpoint of durability, it is preferably from 1 to 20 N/25 mm, and further considering the viewpoint of reprocessing, it is particularly preferable that it is 6 to 12 N/25 mm.

The surface resistivity of the first adhesive layer 21 of the optical film 1A with the adhesive layer of the present embodiment is preferably 1.0 × 10 ¹² Ω/sq or less, more preferably 5.0 × 10 ¹¹ Ω/sq or less. It is preferably 7.0 × 10 ¹⁰ Ω/sq or less. By setting the surface resistivity to the above value or less, it is possible to exhibit sufficient antistatic properties on the display panel. This surface resistivity can be achieved by including the above-mentioned antistatic agent (D) in the adhesive composition P. In addition, the measurement of the surface resistivity of the first adhesive layer 21 is carried out in accordance with JIS K6911, and is specifically shown in the test examples described later. In addition, 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 unevenness.

7. Use of an optical film with an adhesive layer

The optical film 1A to which the adhesive layer is attached in the present embodiment is an optical film 1B to which an adhesive layer is attached, which will be described later, and a polarizing plate is laminated on the second retardation film 12 to be a composite with an adhesive layer. Use with a polarizing plate. By using the composite polarizing plate with an adhesive layer, for example, a liquid crystal display device including a liquid crystal cell and a composite polarizing plate can be manufactured. The details will be described in the paragraph of the optical film 1B with the adhesive layer described later.

[Optical film with an adhesive layer according to the second embodiment]

As shown in FIG. 3, the optical film 1B with an adhesive layer according to the second embodiment of the present invention is configured to include a first retardation film 11 and a layer laminated on the first retardation film 11 (the lower side in FIG. 3). a first adhesive layer 21; a second adhesive layer 22 laminated on one surface side (upper side in FIG. 3) opposite to the surface on the first adhesive layer 21 side of the first retardation film 11; The second phase difference plate 12 of the second adhesive layer 22 on the opposite side to the surface on the first retardation plate 11 side (the upper side in FIG. 3); and the second phase difference plate 12 and the second layer The polarizing plate 3 on the side opposite to the surface on the side of the adhesive layer 22 (the upper side in FIG. 3). In other words, the optical film 1B with the adhesive layer of the second embodiment is formed by laminating the polarizing plate 3 on the optical film 1A with the adhesive layer of the first embodiment. Thereby, it is possible to provide a composite polarizing plate with an adhesive layer having excellent viewing angle compensation performance. In addition, the composite polarizing plate of the present embodiment includes the first retardation film 11, the second adhesive layer 22, the second retardation film 12, and the polarizing plate 3.

The optical film 1B with an adhesive layer according to the second embodiment The first phase difference plate 11, the first adhesive layer 21, the second adhesive layer 22, and the second retardation film 12 respectively have the first phase difference plate 11 of the optical film 1A with the adhesive layer attached thereto according to the first embodiment. The first adhesive layer 21, the second adhesive layer 22, and the second retardation film 12 have the same structure. Further, although not shown, a release sheet may be laminated on the surface (the lower surface in FIG. 3) of the first adhesive layer 21 on the side opposite to the first retardation film 11 side, until the optical layer with the adhesive layer is attached. Film 1B was used.

In the optical film 1B with the adhesive layer described above, even when the optical film (composite polarizing plate) used has been thinned compared with the conventional product, it is excellent in durability when used in a display panel. The occurrence of warping or surface peeling can also be suppressed under high temperature conditions, under moist heat conditions or under thermal shock. Further, the display panel is not easily warped under high temperature conditions, and heat unevenness is less likely to occur.

Polarizer

The polarizing plate 3 of the present embodiment is configured to include a polarizer 31 on the side of the second retardation film 12 and a protective layer 32 on the side opposite to the second retardation film 12. Further, although not shown, the adhesive layer may be sandwiched between the polarizer 31 and the protective layer 32 and/or between the polarizer 31 and the second retardation film 12.

(1) polarizer

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

The polyvinyl alcohol-based resin constituting the polarizer 31 can be obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, acetic acid B is also exemplified. An enester and other monomer copolymers copolymerizable therewith. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.

The degree of saponification of the polyvinyl alcohol-based resin is usually in the range of 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin can be further modified. For example, polyvinyl formal or polyvinyl acetal modified with an aldehyde may also be used. The degree of polymerization 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 preferably produced by the following process: the uniaxial stretching of the polyvinyl alcohol resin film; the dyeing and adsorption of the polyvinyl alcohol resin film by the dichroic dye The dichroic dye; and the polyvinyl alcohol-based resin film in which the dichroic dye is adsorbed by the aqueous boric acid solution.

The uniaxial stretching can be carried out before the dyeing with the dichroic dye, simultaneously with the dyeing with the dichroic dye, or after the dyeing with the dichroic dye. When uniaxially stretching after dyeing with a dichroic dye, the uniaxial stretching can be carried out before the boric acid treatment or during the boric acid treatment. Of course, uniaxial stretching can also be performed at these multiple stages. When performing uniaxial stretching, it may be extended to a single axis between rolls having different circumferential speeds, or may be extended to a single axis using a heat roll. Further, it may be a dry stretching which is extended in the atmosphere, or may be a wet stretching which is extended in a state of being swollen by a solvent. The stretching ratio is usually about 4 to 8 times.

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

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

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in the aqueous boric acid solution 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, potassium iodide is preferably contained in the aqueous boric acid solution. The content of potassium iodide in the aqueous boric acid solution is usually from 2 to 20 parts by mass, preferably from 5 to 15 parts by mass, per 100 parts by mass of water. The immersion time in the aqueous boric acid solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the aqueous boric acid solution is usually 50 ° C or higher, preferably 50 to 85 ° C.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. After washing with water, it was dried to obtain a polarizer 31. The water temperature in the water washing treatment is usually about 5 to 40 ° C, and the immersion time is usually about 2 to 120 seconds. The drying treatment thereafter is usually carried out using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 °C. In addition, drying The processing time is usually about 120~600 seconds.

The thickness of the polarizer 31 is preferably about 3 to 50 μm, and particularly preferably about 3 to 15 μm 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 film which is uniaxially or biaxially stretched.

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. Resin. Among the above, the protective layer 32 is preferably made of a cellulose resin.

The cellulose-based resin is a resin obtained by esterifying at least a part of a hydroxyl group in cellulose, and may be a mixed ester in which a part is acetated and partially esterified. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetamino cellulose resin. Specific examples of the acetaminophen-based resin include triacetonitrile cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. As a commercial item of the film which consists of such an acetyl cellulose-type resin, the "Fujitac TD80", "Fujitac TD80UF" and "Fujitac TD80UZ" by the FUJIFILM Corporation, and Konica Minolta Opto Products Co., Ltd. are mentioned, for example. "KC8UX2M", "KC2UA" and "KC8UY" manufactured by the company.

A cellulose resin film to which an optical compensation function is imparted can also be used as the protective layer 32. As the optical compensation film, for example, a film containing a compound having a phase difference adjustment function in a cellulose resin; A compound having a phase difference adjusting function is applied to the surface of the resin, and a film obtained by stretching the cellulose resin uniaxially or biaxially. Examples of the optical compensation film of the cellulose-based resin which is commercially available are "Wide View Film WV BZ 438" manufactured by FUJIFILM Corporation and "Wide View Film WV EA", manufactured by Konica Minolta Opto Products Co., Ltd. "KC4FR-1" and "KC4HR-1", etc.

Among the above-mentioned cellulose-based resins, the protective layer 32 is preferably composed of a cellulose ester-based resin, and particularly preferably composed of an acetaminocellulose-based resin, and further preferably composed of triacetyl cellulose.

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

Before the protective layer 32 is bonded to the polarizer 31, the bonding surface can be subjected to an easy subsequent treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment, or the like. Further, the surface of the protective layer 32 opposite to the bonding surface of the polarizer 31 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 μm, preferably 10 to 120 μm, particularly preferably 10 to 85 μm, still more preferably 10 to 30 μm.

(3) adhesive layer

The adhesive which can be sandwiched between the polarizer 31 and the protective layer 32 and/or the adhesive layer between the polarizer 31 and the second retardation film 12 can be suitably selected depending on the type and purpose of the object to be placed. Use the appropriate person. For example, a solvent type adhesive, an emulsion type adhesive, a water-based adhesive, a pressure-sensitive adhesive, and a rewet connection are mentioned. A coating agent, a polycondensation type adhesive, a solventless type adhesive, a film-like adhesive, a hot melt type adhesive, and the like.

A preferred adhesive agent constituting the above-mentioned adhesive is a water-based adhesive, and a representative example thereof is a polyvinyl alcohol-based resin as a main component. For example, a commercially available polyvinyl alcohol-based resin which is a water-based adhesive, for example, "KL-318" manufactured by KURARAY CO., LTD.

The above aqueous binder 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 or the like is preferable, and an epoxy group compound is particularly preferable. As a commercial product of a crosslinking agent, for example, "Sumirez Resin 650 (30)" which is an aqueous solution of glyoxal or a water-soluble epoxy compound sold by Sumika Chemtex Company, Limited, etc. are mentioned.

As another preferable adhesive agent, an adhesive agent composed of an epoxy resin composition containing an epoxy resin which is cured by irradiation with an active energy ray or heating is exemplified. When the adhesive is used, the adhesion between the films can be carried out by irradiating the adhesive layer sandwiched between the films with an active energy ray or heating to cure the curable epoxy resin contained in the adhesive. The curing of the epoxy resin by irradiation or heating of the active energy ray is preferably carried out by cationic polymerization of an epoxy resin, and the epoxy resin in the present specification means having two or more rings in the molecule. A compound of an oxy group.

From the viewpoint of weather resistance, refractive index, and cationic polymerizability, the epoxy resin contained in the adhesive, that is, the curable epoxy resin composition is preferably an epoxy resin containing no aromatic ring in the molecule. As such an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are illustrated.

2. Method for producing an optical film with an adhesive layer

A preferred embodiment of the method of producing the optical film 1B with the adhesive layer will be described.

(1) Manufacture of composite polarizing plate

The manufacture of the composite polarizing plate can be carried out by a usual method. Hereinafter, a method of producing a water-based adhesive as the above-mentioned adhesive will be described as an example.

First, a coating film constituting the adhesive of the second adhesive layer 22 is formed on the peeling surface of the release sheet. Specifically, the coating solution constituting the adhesive of the second adhesive layer 22 is applied to the release surface of the release sheet and then dried.

On the other hand, an adhesive layer is formed on the bonding surface of the polarizer 31 or the bonding surface of the second phase difference plate 12 and the protective layer 32. The formation of the subsequent agent layer can be performed, for example, by a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. In addition, it is also possible to continuously supply the polarizer 31 and the protective layer 32 so that the bonding surfaces of both of them are inside, and to form an adhesive between them. After applying the adhesive, heat treatment is performed as needed to evaporate water, thereby drying the adhesive layer.

The film thickness of the subsequent layer can be arbitrarily set according to the characteristic design of the polarizing plate 3. However, from the viewpoint of reducing the cost of the adhesive material, the smaller one is preferable, and the viewpoint of suppressing defects such as bubbles or foreign matter at the time of bonding is considered. In view of the above, the larger one is preferable, and from the viewpoint of adhesion and durability, it is preferably carried out in an optimum range determined for each combination of the adherend and the adhesive. It is usually 0.005 to 10 μm, preferably 0.01 to 5 μm, and more preferably 0.03 to 1 μm.

Followed by the second phase difference plate 12 and the polarizer 31, or followed by polarization In the case of the sub-31 and the protective layer 32, one or both of the bonding surfaces may be subjected to corona discharge treatment, plasma treatment, flame treatment, primer treatment before forming the coating layer of the adhesive. The anchor coating treatment is easy to handle.

After the adhesive layer is formed as described above, the protective layer 32 is bonded to one surface of the polarizer 31 via the adhesive layer, and the second retardation film 12 is bonded to the other surface of the polarizer 31, thereby obtaining protection. The layer 32, the polarizer 31, and the second phase difference plate 12 constitute a laminate.

Thereafter, a coating film constituting the adhesive of the second adhesive layer 22 on the release sheet is bonded to the surface of the obtained laminate on the side of the second retardation film 12 side. Then, the coating film of the adhesive is cured by irradiating the active energy ray through the release sheet, and the coating film is referred to as the second adhesive layer 22. The irradiation conditions of the active energy ray and the like are the same as those of the above-described optical film 1A to which the adhesive layer is attached.

Finally, the release sheet is peeled off from the second adhesive layer 22 formed as described above, and the surface on the second acrylic resin layer 113 side of the first retardation film 11 is bonded to the exposed second adhesive layer 22 . Thereby, the composite polarizing plate 2B in which the protective layer 32, the polarizer 31, the second retardation film 12, the second adhesive layer 22, and the first retardation film 11 are laminated is obtained.

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

(2) Manufacture of the adhesive sheet of the first adhesive layer

On the other hand, an adhesive sheet in which a release sheet is laminated on the surface or both surfaces of the first adhesive layer 21 formed of the adhesive composition P is produced. Here, as an example, an adhesive sheet formed by laminating a release sheet on both surfaces of the first adhesive layer 21 is used. The adhesive sheet can be produced by the method described in the method of producing the optical film 1A to which the adhesive layer is attached.

(3) Manufacture of optical film with adhesive layer

A peeling sheet (light peeling type peeling sheet) on one side was peeled off from the adhesive sheet obtained as described above. Then, the first retardation film 11 of the composite polarizing plate is superposed on the exposed first adhesive layer 21, and the adhesive sheet and the composite polarizing plate are pressed. Thereby, the optical film 1B (with a peeling sheet) with the above-mentioned adhesive layer was obtained.

In another example of the method for producing the optical film 1B with the adhesive layer, a solution containing the adhesive composition P is applied onto the release surface of the release sheet, and heat treatment is performed to form a coating film, and then the composite polarizing plate is formed. The first retardation film 11 is superposed on the coating film. When the coating film is required to have a curing period, the adhesive layer is formed at intervals of the curing period, and when the curing period is not required, the first adhesive layer 21 is directly formed. Thereby, the optical film 1B (with a peeling sheet) with the above-mentioned adhesive layer was obtained.

3. Physical properties of an optical film with an adhesive layer

The adhesive force and surface resistivity of the optical film 1B with the adhesive layer of the present embodiment are the same as those of the optical film 1A with the adhesive layer described above.

4. Use of an optical film with an adhesive layer

By using the optical film 1B with an adhesive layer, for example, a liquid crystal display device including a liquid crystal cell and a composite polarizing plate can be manufactured.

Specifically, the first adhesive layer 21 of the optical film 1B to which the adhesive layer is attached (when the release sheet is laminated, the first adhesive layer 21 which is peeled off after the release sheet is peeled off) is superposed on the liquid crystal cell The desired face can be pressed. Thereby, a liquid crystal display device having a liquid crystal cell and a composite polarizing plate can be obtained Set.

The first adhesive layer 21 of the optical film 1B with the adhesive layer of the present embodiment is excellent in durability, and even if the obtained liquid crystal display device is placed under high temperature conditions, under moist heat conditions or under thermal shock, It is possible to suppress the occurrence of warping or surface peeling at the interface of the first adhesive layer 21. For example, when the glass plate to which the optical film 1B with the adhesive layer is attached is placed under high temperature conditions of 85 ° C or under hot humid conditions of 60 ° C and 90% RH for 250 hours, or -35 ° C to 70 is applied. In the case of thermal shock of °C (each 30 minutes, 200 cycles), it is possible to suppress the occurrence of warping or surface peeling.

Further, the first adhesive layer 21 of the optical film 1B with the adhesive layer of the present embodiment is excellent in stress relaxation property, and the obtained liquid crystal display device is less likely to warp under high temperature conditions, and it is difficult to generate heat. Uneven. For example, when the glass plate to which the optical film 1B with the adhesive layer is attached is left under high temperature conditions (for example, at 80 to 85 ° C) for 250 hours, it is not easy to warp, and it is difficult to generate heat. All. In particular, even if the composite polarizing plate is a film, the liquid crystal display device is less likely to warp, and even if the liquid crystal cell is high-precision, heat unevenness is less likely to occur.

A transparent conductive film may also be present on the surface of the liquid crystal cell to which the first adhesive layer 21 is in contact. Examples of the transparent conductive film include metals such as platinum, gold, silver, and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc oxide, tin-doped indium oxide (ITO), and oxidation. Composite oxides such as zinc-doped indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, chalcogenide, lanthanum hexaboride, titanium nitride, titanium carbide, etc. A non-oxidizing compound or the like.

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

[Examples]

Hereinafter, the present invention will be specifically described by way of Examples and the like, but the scope of the present invention is not limited to the Examples and the like.

[Example 1]

1. Manufacture of optical film (composite polarizing plate)

(1) Production of polarized photons

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

(2) Production of polarizing plate

Preparation 3 parts by mass of carboxy-modified polyvinyl alcohol (KURARAY CO., LTD., trade name "KL-318") was dissolved in 100 parts by mass of water, and 1.5 parts by mass of water-soluble epoxy was added to the aqueous solution. A resin, that is, an epoxy-based epoxy-based additive (manufactured by Taoka Chemical Co., Ltd., trade name "Sumirez Resin 650 (30)", an aqueous solution having a solid concentration of 30% by mass) Follow-up agent. This epoxy-based adhesive is applied to one surface of the polarizer obtained by the above.

On the coating layer of the above epoxy-based adhesive, a 35 μm-thick triethylcellulose film (manufactured by Konica Minolta Opto Products Co., Ltd., trade name "KC2UA") having a saponified surface was attached as a coating layer. The protective layer is obtained to obtain a polarizing plate in which a protective layer and a polarizer are laminated.

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

Next, an epoxy-based adhesive is applied to the other surface of the polarizer of the polarizing plate in the same manner as described above, and a zero-phase difference of a cyclic olefin resin having a thickness of 23 μm is bonded to the coating layer. A film (manufactured by Zeon Corporation, trade name "ZEONOR") was used as the second retardation film. Thereafter, the film was dried at 80 ° C for 5 minutes, whereby the first protective layer and the second protective layer were followed by a polarizer. After that, it was cured at 40 ° C for 168 hours to obtain a build-up protective layer (layer thickness: 25 μm), a polarizer (extension ratio of 5 times, a layer thickness of 15 μm), and a second phase difference plate (layer thickness of 23 μm) to have a total thickness of 63 μm. Laminated body.

(4) Formation of a coating film of an active energy ray curable adhesive

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

Tris(propylene oxyethyl) isocyanurate which is 100 parts by mass of the above (meth) acrylate polymer (X) as an active energy ray curable compound (Y) (polyfunctional monomer) (manufactured by TOAGOSEI CO., LTD., trade name "ARONIXM-315") 15 parts by mass, trihydroxyl as a crosslinking agent (Z) Methylpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATEL") 0.3 parts by mass, benzophenone and 1-hydroxycyclohexyl phenyl ketone as a polymerization initiator 1.5 parts by mass of a mixture which was mixed at a mass ratio of 1:1 (manufactured by Chiba Specialty Chemicals Co., Ltd., trade name "IRGACURE 500"), and 3-glycidoxypropyltrimethoxydecane as a decane coupling agent (Shin- 0.2 parts by mass manufactured by Etsu Chemical Co., Ltd., trade name "KBM403"), and the mixture was thoroughly stirred and diluted with ethyl acetate to obtain a coating solution of an active energy ray-curable adhesive.

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

(5) Production of the first phase difference plate

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

(6) Production of composite polarizing plate

The coating film of the active energy ray-curable adhesive obtained by the above process (4) is bonded to the surface of the second phase difference plate side of the laminate obtained by the above process (3), and the release film is passed through The ultraviolet ray is irradiated under conditions, and the coating film of the above-mentioned adhesive is hardened to become a second adhesive layer. After that, the release sheet is peeled off from the obtained second adhesive layer, and then the second acrylic layer of the first retardation film obtained by the above process (5) is bonded to the surface of the exposed second adhesive layer. The surface on the side of the resin layer. Thus, a composite polarizing plate (optical film) having a total thickness of 93 μm formed by laminating a protective layer, a polarizer, a second retardation plate, a second adhesive layer, and a first retardation film was obtained. Further, the thickness of the formed second adhesive layer was 5 μm.

<Ultraviolet irradiation conditions>

. Use high pressure mercury lamp

. Illuminance 300mW/cm ² , light quantity 300mJ/cm ²

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

2. Manufacture of optical films with an adhesive layer

(1) Preparation of (meth) acrylate copolymer

Preparation of (meth) acrylate copolymer by copolymerizing 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 (A). Measured by the method described later The molecular weight of the (meth) acrylate copolymer (A) was determined, and as a result, the weight average molecular weight (Mw) was 1.6 million. Further, according to the above compounding, the (meth) acrylate copolymer (A) had a hydroxyl value of 14.49 mgKOH/g and an acid value of 0 mgKOH/g.

(2) Preparation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained by the above process (1), trimethylolpropane modified as a crosslinking agent (B), modified by xylene phenyl diisocyanate (Mitsui Chemicals, Manufactured by Inc., trade name "TAKENATE D110N") 0.2 parts by mass of 3-glycidoxypropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd.) as an epoxy group-containing decane coupling agent (C1). , trade name "KBM403") 0.2 parts by mass of a cocondensate of 3-mercaptopropyltrimethoxydecane and methyltriethoxydecane as a mercaptodecane coupling agent (C2) (Shin-Etsu Chemical Co.) , manufactured by Ltd., trade name ""X-411-1810", fluorenyl equivalent: 450 g/mole) 0.2 parts by mass, and N-octyl-4-methylpyridinium hexafluoride as antistatic agent (D) 2.0 parts by mass of phosphate (an ionic compound which is solid at room temperature) was mixed, and the mixture was thoroughly stirred and diluted with ethyl acetate to obtain a coating solution of an adhesive composition.

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

[(Meth)acrylate copolymer]

BA: n-butyl acrylate

HEA: 2-hydroxyethyl acrylate

IBXA: Isobornyl acrylate

PhEA: 2-phenylethyl acrylate

CHA: cyclohexyl acrylate

2EHA: 2-ethylhexyl acrylate

[Isocyanate crosslinking agent]

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

TDI: trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATEL")

[antistatic agent]

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

(3) Fabrication of an optical film with an adhesive layer

A release sheet of a release sheet (SP-PET3811, thickness: 38 μm manufactured by LINTEC Corporation) which was subjected to a release treatment on the side of the polyethylene terephthalate film by a phthalone-based release agent, and coated with a knife coater. After coating the coating solution of the adhesive composition obtained by the cloth, it was heat-treated at 90 ° C for 1 minute to form a coating film of the adhesive composition.

Then, the composite polarizing plate obtained as described above is bonded to the coating film at 23 ° C and 50 so that the surface of the first acrylic resin layer of the first retardation film is in contact with the exposed surface of the coating film. The film was cured under %RH for 7 days to obtain an optical film with an adhesive layer formed on the composite polarizing plate. Further, the thickness of the adhesive layer (first adhesive layer) formed was 20 μm.

[Examples 2 to 13, Comparative Example 1]

The type and ratio of each monomer constituting the (meth) acrylate copolymer (A), the weight average molecular weight of the (meth) acrylate copolymer (A), and the type and coordination of the crosslinking agent (B) An optical film with an adhesive layer was produced in the same manner as in Example 1 except that the amounts shown in Table 1 were changed.

[Comparative Example 2]

A coating film formed by adding an antistatic agent (D) to an adhesive having the same composition as the second adhesive layer (see Table 1) is used instead of the coating film for forming the adhesive composition of the first adhesive layer. On the release sheet (SP-PET 3811, thickness: 38 μm, manufactured by LINTEC Corporation), the outermost surface of the first retardation film of the composite polarizing plate was bonded to the exposed surface of the coating film, and then peeled off. The sheet was irradiated with ultraviolet rays under the following conditions, and then cured at 23 ° C and 50% RH for 7 days, except that the same operation as in Example 1 was carried out to produce an adhesive layer formed on the composite polarizing plate (first An optical film with an adhesive layer attached to the adhesive layer). Further, the thickness of the first adhesive layer was 20 μm.

<Ultraviolet irradiation conditions>

. Use high pressure mercury lamp

. Illuminance 300mW/cm ² , light quantity 300mJ/cm ²

. UV illuminance and light meter use "UVPF-A1" manufactured by EYE GRAPHICS CO., LTD.

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

<Measurement conditions>

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

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

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

. Determination of solvent: tetrahydrofuran

. Measuring temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)

A release sheet (SP-PET3801, thickness: 38 μm, manufactured by LINTEC Corporation) which was subjected to a release treatment with an anthrone-based release agent on one side of polyethylene terephthalate was used to prepare an adhesive sheet instead of the examples and comparative examples. An optical film used in the production of an optical film with an adhesive layer. Specifically, the above-mentioned coating film formed of the coating film of the release sheet/adhesive composition (for the first adhesive layer) obtained in the production process of the embodiment or the comparative example is as described above. The release sheet was laminated so as to be in contact with the release-treated surface side, and cured at 23 ° C and 50% RH for 7 days. Thus, an adhesive sheet composed of a structure of a release sheet (SP-PET3801) / a first adhesive layer (thickness: 20 μm) / a release sheet (SP-PET 3811) was produced. Further, in the case of producing the adhesive sheet having the first adhesive layer (thickness: 20 μm) of Comparative Example 2, ultraviolet irradiation was performed before curing in the same manner as in the case of producing the optical film with the adhesive layer of Comparative Example 2.

The obtained adhesive sheet was cut into a size of 80 mm × 80 mm, and the adhesive layer was coated on a polyester mesh (mesh fabric size 200), and the mass was weighed by a precision balance, minus The quality of the above-mentioned mesh fabric alone, thereby calculating the quality of only the adhesive. Set the quality at this time to M1.

Next, the adhesive coated on the above-mentioned polyester mesh fabric was immersed in ethyl acetate at room temperature (23 ° C) for 24 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in 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 by a precision balance, and the mass of the above-mentioned mesh fabric was subtracted, thereby calculating the quality of only the adhesive. Set the quality at this time to M2. The gel fraction (%) is represented by (M2/M1) × 100. The results are shown in Table 2.

In addition, the second adhesive layer obtained by curing the coating film of the active energy ray-curable adhesive formed in the examples and the comparative examples was subjected to the same operation as described above to measure the gel fraction (%). The results are shown in Table 2.

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

The same operation as in Test Example 1 was carried out to prepare an adhesive sheet having a structure of a release sheet (SP-PET3801) / a first adhesive layer (thickness: 20 μm) / a release sheet (SP-PET 3811).

In addition, the same operation as in the examples and the comparative examples was carried out except that the release sheet (SP-PET3801) and the release sheet (SP-PET 3811) were used instead of the polarizing plate and the first retardation film of the optical film. An adhesive sheet composed of a structure of a release sheet (SP-PET3801) / a second adhesive layer (thickness: 5 μm) / a release sheet (SP-PET 3811).

The first adhesive layer and the second adhesive layer formed in the above process were laminated in a plurality of layers with a thickness of 3 mm. A cylindrical body (having a height of 3 mm) having a diameter of 8 mm was punched out from the laminated body of the obtained adhesive layer, and this was taken as a sample.

According to JIS K7244-6, a viscoelasticity measuring device (manufactured by RHEOMETRIC SCIENTIFIC, DYNAMIC ANALAYZER) The storage elastic modulus (MPa) of the above sample was measured by the following conditions using a torsional shear method. The results are shown in Table 2.

Measurement frequency: 1 Hz

Measuring temperature: 85 ° C

[Test Example 3] (durability evaluation)

The optical film with the adhesive layer obtained in the examples and the comparative examples was cut to prepare a sample having a size of 150 mm × 200 mm. The release sheet was peeled off from the sample and attached to an alkali-free glass (Eagle XG, manufactured by Corning Incorporated) via an exposed adhesive layer, and then autoclaved by KURIHARA Co., Ltd. was pressurized at 0.5 MPa and 50 ° C for 20 minutes. .

Thereafter, the mixture was placed in an environment of three durability conditions as follows, and after 50 hours, the presence or absence of warping or surface peeling was confirmed with a 10x magnification. The evaluation criteria are as follows. The results are shown in Table 2.

◎: No lift or surface peeling was confirmed.

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

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

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

<endurance condition>

. Heat resistance: 85 ° C dry

. Damp heat: 60 ° C, relative humidity 90% RH

. HS: -35 ° C 30 minute thermal shock test at 70 ° C, 200 cycles

[Test Example 4] (evaluation of warpage resistance)

The optical film with the adhesive layer obtained in the examples and the comparative examples The cutting length is 200mm and the width is 150mm. The release sheet was peeled off from the optical film with the adhesive layer, and the exposed adhesive layer was bonded to an alkali-free glass (manufactured by Corning Incorporated, trade name "Eagle-XG") having a length of 250 mm, a width of 175 mm, and a thickness of 0.5 mm. The central part of this is taken as a sample. The sample was allowed to stand at 85 ° C for 250 hours under a dry atmosphere. Thereafter, it was taken out at 25 ° C and 50% RH, and the optical film was placed on the water platform with the side facing up, and the amount of warpage of the corners of the sample (4 points) from the stage (the distance between the corner and the table) was measured. ), the amount of warpage of each corner is totaled. According to the results, the warpage resistance was evaluated as follows. The results are shown in Table 2.

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

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

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

×: The total amount of warpage exceeds 20 mm

[Test Example 5] (Evaluation of heat resistance unevenness)

The optical film with the adhesive layer obtained in the examples and the comparative examples was adjusted to a size of 200 mm × 150 mm by a cutting device (Super Cutter PN1-600 manufactured by Ogino Seisakusho Co., Ltd.). The release sheet was peeled off and attached to an alkali-free glass (Eagle XG, manufactured by Corning Incorporated) via an exposed adhesive layer, and then autoclaved by KURIHARA Co., Ltd. was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Further, the bonding is performed on the front and back surfaces of the alkali-free glass so that the polarization axis of the optical film with the adhesive layer is in a state of being orthogonally polarized (polarizing axis: ∠45°, ∠135°). In this state, after standing in a dry environment at 80 ° C for 250 hours, it was allowed to stand in an environment of 23 ° C and 50% RH for 2 hours, and this was used as a sample, and the heat unevenness was evaluated by the method shown below. . The results are shown in Table 2.

<Evaluation method>

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

◎: The brightness distribution is substantially uniform.

○: The brightness distribution of the four sides has some distortion.

△: The brightness distribution of the four sides has significant distortion.

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

[Test Example 6] (Adhesion measurement - reprocessing evaluation)

The optical film with the adhesive layer obtained in the examples and the comparative examples was cut into a sample having a width of 25 mm and a length of 100 mm, and the release sheet was peeled off and attached to the alkali-free glass via the exposed adhesive layer (manufactured by Corning Incorporated). After the Eagle XG), the autoclave manufactured by KURIHARA Co., Ltd. was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Thereafter, it was allowed to stand under the conditions of 23 ° C and 50% RH for 24 hours, and was measured under the conditions of a peeling speed of 300 mm/min and a glass angle of 180 degrees using a tensile tester (manufactured by ORIENTEC Co., Ltd., TENSILON). Adhesion (adhesion after 1 day; N/25mm). Conditions other than this were measured in accordance with JIS Z 0237:2009. The results are shown in Table 2.

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

The reprocessing property was evaluated based on the adhesion after 14 days from the attachment. The results are shown in Table 2.

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

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

△: The adhesion after 14 days of attachment is 10N/25mm or more, less than 20N/25mm

×: The adhesion after 14 days of attachment is 20N/25mm or more

[Test Example 7] (Measurement of surface resistivity of the adhesive layer)

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

【Table 1】

As is clear from Table 2, the optical film with an adhesive layer obtained in the examples was excellent in durability, and was not easily warped at a high temperature, and heat unevenness was less likely to occur. Further, the optical film-based pressure-sensitive adhesive layer having an adhesive layer obtained in the examples has a low surface resistivity and a small adverse effect on a liquid crystal cell or the like. Enter Further, the optical films with the adhesive layers obtained in Examples 1 to 12 were also excellent in reworkability.

[Industrial availability]

The optical film with an adhesive layer of the present invention is suitable for laminating a thinned composite polarizing plate and a liquid crystal cell.

1A‧‧‧Optical film with adhesive layer

11‧‧‧1st phase difference plate

12‧‧‧2nd phase difference plate

21‧‧‧1st adhesive layer

22‧‧‧2nd adhesive layer

Claims (7)

An optical film with an adhesive layer, comprising: a first retardation film; a first adhesive layer laminated on one surface of the first retardation film; and a first adhesive layer laminated on the first retardation film a second adhesive layer on the side opposite to the surface on the side of the agent layer; and a second retardation plate laminated on the side opposite to the surface on the side of the first retardation plate of the second adhesive layer; The optical film of the adhesive layer is characterized in that the surface of the first retardation film that is in contact with the first adhesive layer is made of an acrylic resin, and the gel fraction of the adhesive constituting the first adhesive layer is 55 to 90%, the storage elastic modulus (G') at 85 ° C of the first adhesive layer is 0.03 to 0.25 MPa, and the gel fraction of the adhesive constituting the second adhesive layer is 80 to 100%. The storage elastic modulus (G') at 85 ° C of the second adhesive layer is 0.15 to 3.00 MPa. The optical film with an adhesive layer according to claim 1, wherein the outermost layer of the first retardation film that is in contact with the first adhesive layer is an acrylic resin formed by extrusion molding. Layer composition. The optical film with an adhesive layer according to the second aspect of the invention, wherein the first retardation film comprises: the acrylic resin layer; and a second acrylic resin layer; A phase difference expression layer located between the acrylic resin layer and the second acrylic resin layer. An optical film with an adhesive layer as described in claim 3, wherein the phase difference expression layer is composed of a styrene resin. The optical film with an adhesive layer as described in claim 1, wherein the second retardation film is made of a cyclic olefin resin. The optical film with an adhesive layer according to claim 1, wherein the first adhesive layer is composed of an adhesive obtained from an adhesive composition, and the adhesive composition contains: (meth)acrylic acid. The ester copolymer (A) contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer; and a crosslinking agent (B). The optical film with an adhesive layer as described in claim 1, wherein a polarizing plate is further laminated on a side of the second retardation film opposite to the surface on the second adhesive layer side.