JP2009294607A - Retardation film with adhesive layer, elliptical polarizing plate using the same, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retardation film with an adhesive layer which is improved in adhesion between the retardation film made of a polypropylene resin and the adhesive, and to provide an elliptical polarizing plate and a liquid crystal display device using the retardation film. <P>SOLUTION: The retardation film with adhesive layer includes the retardation film 20 made of the polypropylene resin, a primer layer 30, and the adhesive layer 40, in this order. The primary layer 30 is made of (a) a copolymer containing a monomer unit derived from a vinyl compound expressed as CH2=CH-R (in the formula, R is a cycloalkyl group, secondary alkyl group, or tert alkyl group), (b) a monomer unit derived from unsaturated carboxylic acids, and (c) a monomer unit derived from a straight-chain ethylenically carbon hydride having a double bond at 1,2-position. The elliptical polarizing plate and the liquid crystal display device using the retardation film are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a retardation film, and more particularly to a retardation film with an adhesive layer obtained by laminating a specific primer layer and an adhesive layer on a retardation film made of a polypropylene resin. The present invention also relates to an elliptically polarizing plate and a liquid crystal display device using the retardation film with an adhesive layer.

  In recent years, liquid crystal display devices have rapidly spread as information display devices such as mobile phones, portable information terminals, computer monitors, and televisions by taking advantage of low power consumption, low voltage operation, light weight, and thinness. Yes. With the development of liquid crystal technology, liquid crystal displays in various modes have been proposed, and problems with liquid crystal displays such as response speed, contrast, and viewing angle are being solved. However, it is still pointed out that the viewing angle is narrower than that of a cathode ray tube (CRT), and various attempts have been made to expand the viewing angle.

  One means for expanding the viewing angle in a liquid crystal display is to use a retardation film that matches the mode of the liquid crystal. Examples thereof include a birefringent film made of a stretched film of various plastics, a film in which a discotic liquid crystal or a nematic liquid crystal is oriented and fixed, and a film substrate on which the above liquid crystal layer is formed.

  Specific examples of the birefringent film include stretched films such as polycarbonate resin, polystyrene resin, polymethyl methacrylate resin, polyolefin resin, and polyamide resin.

  As a retardation film of polyolefin resin, an amorphous cyclic polyolefin resin, also called alicyclic polyolefin or norbornene resin, is relatively excellent in heat resistance and moisture resistance, excellent in transparency, and retardation. It is widely used for the reason that the value can be adjusted relatively easily.

  For example, Patent Document 1 shows an example in which a λ / 2 stretched film or a λ / 4 stretched film is produced from a cyclic polyolefin film.

  However, with the recent spread of liquid crystal displays, there is a need for a retardation film that is cheaper than a retardation film made of a cyclic polyolefin film. Patent Document 2 discloses that a polypropylene resin is applied to a retardation film. Polypropylene resins are attracting attention because they can be obtained at a lower cost than cyclic polyolefin resins.

  However, it has become clear that a retardation film made of a chain polyolefin resin such as a polypropylene resin is inferior in adhesiveness to a pressure-sensitive adhesive as compared with a cyclic polyolefin resin. Specifically, when producing an elliptically polarizing plate laminated with a retardation film or other optical member, the adhesive layer is likely to fall off partially, so that the handleability is poor or when heat is applied. When a liquid crystal display device is bonded to an optical film with strong shrinkage, and the liquid crystal display device is exposed to a high temperature, peeling between the retardation film and the adhesive layer may occur. was there.

On the other hand, in Patent Document 3, a polyolefin resin modified with an unsaturated polycarboxylic acid or a derivative thereof and (meth) acrylic acid or a derivative thereof is used as a binder composition for protection or cosmetic purposes such as a polypropylene resin. Although it is described that it is applied, it does not describe adhesiveness with the pressure-sensitive adhesive.
Japanese Patent Laid-Open No. 11-149015 JP 2007-286615 A JP 2004-277617 A

  The objective of this invention is providing the phase difference film with an adhesive layer which the adhesiveness of the phase difference film which consists of polypropylene resin, and an adhesive improved. Moreover, the objective of this invention is providing the elliptically polarizing plate using this retardation film with an adhesive layer. Furthermore, the objective of this invention is providing the liquid crystal display device using the said elliptically polarizing plate.

The present invention comprises a retardation film made of a polypropylene resin, a primer layer laminated on the surface of the retardation film, and an adhesive layer laminated on the surface of the primer layer, the primer layer comprising: Provided is a retardation film with a pressure-sensitive adhesive layer comprising a copolymer containing monomer units (a), (b) and (c).
(A) The following general formula (I):
_{CH 2 = CH-R (I} )
(In the general formula (I), R represents a cycloalkyl group, a secondary alkyl group, or a tertiary alkyl group). A monomer unit derived from a vinyl compound represented by
(B) monomer units derived from unsaturated carboxylic acids, and
(C) A monomer unit derived from a linear ethylene chain hydrocarbon having a double bond at the 1,2-position.

  In the present invention, when the content of all monomer units in the copolymer constituting the primer layer is 100 mol%, the content of the monomer unit (b) in the copolymer is 0 It is preferable that it is 0.01-30 mol%.

  The vinyl compound represented by the general formula (I) is preferably vinylcyclohexane.

  In the present invention, the retardation film made of the polypropylene resin is made of a copolymer of propylene and ethylene, and the content of monomer units derived from the ethylene is preferably 10% by weight or less. The retardation film is preferably a quarter wavelength plate.

  The present invention also relates to an elliptically polarizing plate in which the above-mentioned retardation film with an adhesive layer is laminated on a polarizing plate. The elliptically polarizing plate may include a half-wave plate between the pressure-sensitive adhesive retardation film and the polarizing plate.

  Furthermore, this invention provides a liquid crystal display device provided with a liquid crystal cell and the elliptically polarizing plate of this invention laminated | stacked on the single side | surface or both surfaces of this liquid crystal cell.

  ADVANTAGE OF THE INVENTION According to this invention, the phase difference film with an adhesive layer in which the adhesiveness of a phase difference film and an adhesive layer was improved, and an elliptically polarizing plate using the same are provided. Such a retardation film with an adhesive layer and an elliptically polarizing plate are unlikely to peel off between the retardation film and the adhesive layer. In addition, according to the retardation film with an adhesive layer and the elliptically polarizing plate of the present invention, the retardation film or the elliptically polarizing plate provided with the retardation film bonded to the glass substrate of the liquid crystal cell is peeled off and reattached from the liquid crystal cell. At this time, the adhesive can be prevented from remaining on the glass substrate. Such a retardation film of the present invention and an elliptically polarizing plate using the same can be suitably applied to a liquid crystal display device and the like.

  Hereinafter, the present invention will be described in detail with reference to embodiments. FIG. 1 is a schematic cross-sectional view showing a preferred example of the retardation film with an adhesive layer of the present invention. As shown in FIG. 1, a retardation film 10 with an adhesive layer according to the present invention includes a retardation film 20 made of a polypropylene resin, a primer layer 30 laminated on one surface of the retardation film 20, and a primer And an adhesive layer 40 laminated on the layer 30. Hereinafter, each layer will be described in detail.

<< retardation film with adhesive layer >>
<Phase difference film>
In the present invention, a polypropylene resin is stretched to obtain a retardation film. Since the polypropylene resin film is crystalline, the expression rate of the retardation value is extremely high, and a large retardation value can be easily obtained by stretching. Therefore, by using a polypropylene resin, a retardation film having a desired retardation value can be obtained with a thin film thickness.

Polypropylene resin has a difference (birefringence) Δn ₄₀₀ between the in-plane maximum refractive index and the minimum refractive index at a wavelength of ₄₀₀ nm (birefringence) and a difference (birefringence) between the in-plane maximum refractive index and the minimum refractive index at a wavelength of 500 nm. ) for the ratio between _{Δn 500 (Δn 400 / Δn 500} ) is less than 1.05, when a combination of a half-wave plate and a quarter-wave plate formed of each polypropylene resin, excellent wideband It can be a quarter wave plate. In this specification, the value of Δn ₄₀₀ / Δn ₅₀₀ described above is defined as “wavelength dispersion of phase difference” (in this specification, sometimes simply referred to as “wavelength dispersion”).

Furthermore, since the polypropylene-based resin has a small photoelastic coefficient of about 2 × 10 ⁻¹³ cm ² / dyne, the retardation film is made of polypropylene-based resin, so that a half-wave plate and a quarter-wavelength are obtained. Bonding unevenness can be suppressed at the time of bonding with a plate or at the time of bonding with a linear polarizing plate. Moreover, white spots in the heat resistance test can be suppressed. In addition, since the polypropylene-based resin can be stretched at a high magnification, it is possible to produce a completely uniaxial film by transverse stretching, and it is possible to achieve thinning and widening at the same time, and excellent use efficiency.

  In the present invention, a raw film is obtained by depositing the polypropylene resin, and then stretched to develop a retardation to obtain a retardation film. The film thickness of the retardation film can be, for example, about 25 μm or less, and preferably 20 μm or less. When the film thickness exceeds 25 μm, the merit of thinning becomes difficult to be exhibited effectively. Moreover, when the film thickness is too small, wrinkles and the like are likely to occur in the film, and the handling property at the time of winding and bonding tends to be deteriorated. Therefore, the thickness of the retardation film is preferably 5 μm or more, and more preferably 8 μm or more.

The retardation film used in the present invention preferably has an in-plane retardation value R ₀ in the range of 70 to 160 nm. Further, N _z coefficient of the retardation film is preferably in the range of 0.9 to 1.6, especially more preferably in the range of 0.95 to 1.05. From the above range, the in-plane retardation value R ₀ and the N _z coefficient of the retardation film can be appropriately selected according to the characteristics required for the applied liquid crystal display device. The refractive index of the refractive index n _y, in the thickness direction of the in-plane slow axis direction of the refractive index of the retardation film n _x, plane fast axis direction (direction orthogonal with the slow axis and the plane) _Where n _{z is} the thickness of the retardation film and d is the thickness of the retardation film, the in-plane retardation value R ₀ , the thickness direction retardation value R _th , and the N _z coefficient are respectively expressed by the following formulas (A ), (B) and (C).

_{R 0 = (n x -n y} ) × d (A)
_Rth = [( _nx + _ny ) / 2- _nz ] * d (B)
_{N z = (n x -n z} ) / (n x -n y) (C)
Further, from the above formulas (A), (B), and (C), the relationship between the N _z coefficient, the in-plane retardation value R _0, and the thickness direction retardation value R _th is expressed by the following expression (D). Can be represented.

N _z = R _th / R ₀ +0.5 (D)
In addition, when the _Nz coefficient is approximately 1, it means that _ny and _nz are approximately equal from the above formula (C), and thus such a retardation film is almost completely uniaxial.

(Polypropylene resin)
Next, the polypropylene resin constituting the retardation film used in the present invention will be described in more detail. The polypropylene resin constituting the retardation film used in the present invention can be produced by a method of homopolymerizing propylene or a method of copolymerizing propylene and another copolymerizable comonomer using a polymerization catalyst. . As the polymerization catalyst, a conventionally known polymerization catalyst can be used, and examples thereof include the following.
(1) Ti—Mg-based catalyst comprising a solid catalyst component containing magnesium, titanium and halogen as essential components,
(2) a catalyst system in which a solid catalyst component containing magnesium, titanium and halogen as essential components is combined with an organoaluminum compound and, if necessary, a third component such as an electron donating compound,
(3) Metallocene catalysts.

  Among the catalyst systems described above, in the production of the polypropylene resin used in the retardation film of the present invention, an organic aluminum compound and an electron donating compound are combined with a solid catalyst component containing magnesium, titanium and halogen as essential components. Catalytic systems are most commonly used. Examples of the solid catalyst component containing magnesium, titanium, and halogen as essential components include catalyst systems described in JP-A-61-218606, JP-A-61-287904, JP-A-7-216017, and the like. Can be mentioned.

  As the organoaluminum compound, triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, tetraethyldialumoxane and the like can be preferably used. As the electron donating compound, cyclohexylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butylethyldimethoxysilane, dicyclopentyldimethoxysilane and the like can be preferably used.

  Examples of the metallocene catalyst include catalyst systems described in Japanese Patent No. 2587251, Japanese Patent No. 2627669, Japanese Patent No. 2668732, and the like.

  Polypropylene resin is, for example, a solution polymerization method using an inert solvent typified by a hydrocarbon compound such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, or a liquid monomer as a solvent. It can be produced by a bulk polymerization method or a gas phase polymerization method in which a gaseous monomer is polymerized as it is. Polymerization by these methods may be carried out batchwise or continuously.

  The stereoregularity of the polypropylene resin may be any of isotactic, syndiotactic, and atactic. In the present invention, syndiotactic or isotactic polypropylene resins are preferably used from the viewpoint of heat resistance.

  The polypropylene resin that constitutes the retardation film used in the present invention can be composed of a propylene homopolymer, and is composed of propylene as a main component and a comonomer copolymerizable therewith in a small proportion. There may be. By using a copolymer, the processability and transparency of the polypropylene resin can be improved. When the copolymer is used, the content of the monomer unit derived from the comonomer in the copolymer is, for example, 20% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less. The content of the monomer unit derived from the comonomer in the copolymer is preferably 1% by weight or more, more preferably 3% by weight or more. When the content of the monomer unit derived from the comonomer exceeds 10% by weight, the melting point of the resin is lowered and the heat resistance tends to be deteriorated. Further, when the content of the monomer unit derived from the comonomer is less than 1% by weight, there is a tendency that effects such as improvement in processability and transparency, which can be obtained by copolymerization, are not recognized. When the copolymer of two or more types of comonomer and polypropylene is used, the total content of monomer units derived from all the comonomer contained in the copolymer is preferably within the above range. . The content of the monomer unit derived from the comonomer in the copolymer was measured by infrared (IR) spectrum according to the method described on page 616 of “Polymer Analysis Handbook” (published by Kinokuniya Shoten in 1995). Can be obtained by performing

  Examples of the comonomer copolymerizable with propylene include ethylene and an α-olefin having 4 to 20 carbon atoms. Specific examples of the α-olefin having 4 to 20 carbon atoms include the following.

  1-butene, 2-methyl-1-propene (above, 4 carbon atoms); 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene (above, 5 carbon atoms); Hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl- 1-butene (above, 6 carbon atoms); 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl- 1-butene (above, 7 carbon atoms); 1-octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl- 1-pentene, 2,3,4-trimethyl-1-pen 2-propyl-1-pentene, 2,3-diethyl-1-butene (above, 8 carbon atoms); 1-nonene (9 carbon atoms); 1-decene (10 carbon atoms); Undecene (11 carbon atoms); 1-dodecene (12 carbon atoms); 1-tridecene (13 carbon atoms); 1-tetradecene (14 carbon atoms); 1-pentadecene (15 carbon atoms); Hexadecene (16 carbon atoms); 1-heptadecene (17 carbon atoms); 1-octadecene (18 carbon atoms); 1-nonadecene (19 carbon atoms) and the like.

  Among the copolymerizable comonomers, ethylene and an α-olefin having 4 to 12 carbon atoms are preferably used from the viewpoint of processability. Examples of the α-olefin having 4 to 12 carbon atoms preferably used include 1-butene, 2-methyl-1-propene; 1-pentene, 2-methyl-1-butene, and 3-methyl-1-butene; 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3- 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl-1-butene; Octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl-1-pentene, 2,3,4-trimethyl-1- Penten, 2-propi 1-pentene, 2,3-diethyl-1-butene; 1-nonene, 1-decene, 1-undecene; 1-dodecene, and the like. From the viewpoint of copolymerizability with propylene, ethylene, 1-butene, 1-pentene, 1-hexene and 1-octene are preferable, and ethylene, 1-butene and 1-hexene are more preferable. Accordingly, preferred copolymers include propylene / ethylene copolymers, propylene / 1-butene copolymers and propylene / 1-hexene copolymers.

  The copolymer of propylene and a comonomer copolymerizable therewith may be a random copolymer or a block copolymer, but improves the transparency and workability as a retardation film. From this point of view, a random copolymer mainly composed of propylene is preferable. Of these, a random copolymer of propylene and ethylene is preferable.

  The polypropylene resin constituting the retardation film used in the present invention has a melt flow rate (MFR) measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K 7210 of 0.1 to 200 g / 10 min. In particular, it is preferably in the range of 0.5 to 50 g / 10 minutes. By using a polypropylene resin having an MFR in this range, a uniform film can be obtained without imposing a large load on the extruder.

  The polypropylene resin may contain a known additive as long as the effects of the present invention are not impaired. Examples of the additive include an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a nucleating agent, an antifogging agent, and an antiblocking agent. Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, hindered amine light stabilizers, and the like, and for example, phenolic antioxidant mechanisms in one molecule. It is also possible to use a composite antioxidant having a unit having both a phosphorus-based antioxidant mechanism and a phosphorus-based antioxidant mechanism. Examples of the UV absorber include UV absorbers such as 2-hydroxybenzophenone and hydroxyphenylbenzotriazole, and benzoate UV blockers. The antistatic agent may be polymer type, oligomer type or monomer type. Examples of the lubricant include higher fatty acid amides such as erucic acid amide and oleic acid amide, higher fatty acids such as stearic acid, and salts thereof. Examples of the nucleating agent include sorbitol nucleating agents, organophosphate nucleating agents, and polymer nucleating agents such as polyvinylcycloalkane. As the anti-blocking agent, fine particles having a spherical shape or a shape close thereto can be used regardless of inorganic type or organic type. A plurality of these additives may be used in combination.

(Raw film of polypropylene resin)
In the present invention, when producing a retardation film made of a polypropylene resin, first, the original film is obtained by forming the polypropylene resin. The raw film is preferably transparent and substantially free of in-plane retardation. The method for producing a polypropylene resin film is not particularly limited. For example, an extrusion molding method from a molten resin; a resin dissolved in an organic solvent is cast on a flat plate, and the solvent is removed to produce the original film. An original film of polypropylene resin having substantially no in-plane retardation can be obtained by a solvent casting method for forming a film.

  As an example of a method for producing a raw film, a film forming method (extrusion molding method) by extrusion will be described in detail. In the extrusion molding method, a polypropylene resin is melt-kneaded by rotation of a screw in an extruder and extruded from a T die into a sheet. The temperature of the molten sheet to be extruded is about 180 to 300 ° C. If the temperature of the molten sheet at this time is lower than 180 ° C., the spreadability is not sufficient, the thickness of the obtained film becomes non-uniform, and there is a possibility that the film has a phase difference unevenness. Further, when the temperature exceeds 300 ° C., the resin is easily deteriorated or decomposed, and bubbles may be generated in the sheet or carbides may be contained.

The extruder may be a single screw extruder or a twin screw extruder. For example, when a single screw extruder is used, L / D, which is the ratio of the screw length L to the diameter D, is about 24 to 36, the screw groove space volume V ₁ in the resin supply section, and the screw groove in the resin metering section. The compression ratio, which is the ratio (V ₁ / V ₂ ) to the space volume V ₂ , is about 1.5 to 4 and is a full flight type, a barrier type, or a screw having a Maddock type kneading part. Can be used. From the viewpoint of suppressing deterioration and decomposition of the polypropylene-based resin and uniformly melting and kneading, the barrier type L / D is 28 to 36 and the compression ratio V ₁ / V ₂ is 2.5 to 3.5. It is preferable to use a screw. Moreover, in order to suppress deterioration and decomposition | disassembly of polypropylene resin as much as possible, it is preferable to make the inside of an extruder into a nitrogen atmosphere or a vacuum. Furthermore, in order to remove the volatile gas generated when the polypropylene-based resin deteriorates or decomposes, it is also preferable to provide an orifice of about 1 mmφ to 5 mmφ at the tip of the extruder to increase the resin pressure at the tip of the extruder. Increasing the resin pressure at the leading end of the extruder by installing an orifice means increasing the back pressure at the leading end, thereby improving the stability of extrusion. The diameter of the orifice to be used is more preferably 2 mmφ or more and 4 mmφ or less.

  The T-die used for extrusion preferably has no fine steps or scratches on the resin flow path surface, and the lip portion is plated or coated with a material having a low coefficient of friction with the molten polypropylene resin. Further, a sharp edge shape with a lip tip polished to 0.3 mmφ or less is preferable. Examples of the material having a small friction coefficient include tungsten carbide type and fluorine type special plating. By using such a T-die, it is possible to suppress the generation of the eyes, and at the same time, it is possible to suppress the die line. In the T-die, the manifold has a coat hanger shape and preferably satisfies the following condition (1) or (2), and more preferably satisfies the condition (3) or (4).

(1) When the lip width of the T die is less than 1500 mm: the thickness direction length of the T die> 180 mm,
(2) When the lip width of the T die is 1500 mm or more: the thickness direction length of the T die> 220 mm,
(3) When the lip width of the T die is less than 1500 mm: the length in the height direction of the T die> 250 mm,
(4) When the lip width of the T die is 1500 mm or more: Length in the height direction of the T die> 280 mm.

  By using a T die that satisfies these conditions, the flow of the molten polypropylene resin inside the T die can be adjusted, and the lip portion can be extruded while suppressing thickness unevenness, so that the thickness is increased. An original film having excellent accuracy and a more uniform retardation can be obtained.

  From the viewpoint of suppressing the extrusion fluctuation of the polypropylene resin, it is preferable to attach a gear pump via an adapter between the extruder and the T die. In addition, it is preferable to attach a leaf disk filter to remove foreign substances in the polypropylene resin.

  The molten sheet extruded from the T-die is between a metal cooling roll (also referred to as a chill roll or a casting roll) and a touch roll including an elastic body that rotates by pressing in the circumferential direction of the metal cooling roll. A desired original fabric film can be obtained by clamping and solidifying by cooling. In this case, the touch roll may be one in which an elastic body such as rubber is directly on the surface, or may be one in which the surface of the elastic body roll is covered with an outer cylinder made of a metal sleeve. When using a touch roll in which the surface of the elastic roll is covered with an outer cylinder made of a metal sleeve, cooling is usually performed by directly sandwiching a molten sheet of polypropylene resin between the metal cooling roll and the touch roll. . On the other hand, in the case of using a touch roll whose surface is an elastic body, a biaxially stretched film of a thermoplastic resin can be interposed between the molten sheet of polypropylene resin and the touch roll for sandwiching.

  When the molten sheet of polypropylene resin is cooled and solidified by being sandwiched between the cooling roll and the touch roll as described above, the surface temperature of the cooling roll and the touch roll may be lowered to rapidly cool the molten sheet. preferable. For example, the surface temperature of both rolls is preferably adjusted to a range of 0 ° C. or higher and 30 ° C. or lower. When these surface temperatures exceed 30 ° C., it takes time to cool and solidify the molten sheet, so that the crystal component in the polypropylene resin grows, and the resulting film may be inferior in transparency. . The surface temperature of the roll is preferably less than 30 ° C, more preferably less than 25 ° C. On the other hand, when the surface temperature of the roll is lower than 0 ° C., the surface of the metal cooling roll is dewed and water droplets are attached, which tends to deteriorate the appearance of the raw film.

  Since the surface state of the metal cooling roll used is transferred to the surface of the polypropylene resin film, there is a possibility that the thickness accuracy of the resulting polypropylene resin film may be lowered if the surface is uneven. . Therefore, it is preferable that the surface of the metal cooling roll is in a mirror surface state as much as possible. Specifically, the roughness of the surface of the metal cooling roll is preferably 0.3 S or less, more preferably 0.1 S to 0.2 S, expressed as a standard sequence of the maximum height. .

  As for the metal roll and the touch roll forming the nip part, the surface hardness of the elastic body is 65 to 80 as a value measured by a spring type hardness test (A type) defined in JIS K 6301. It is preferable that there is, more preferably 70-80. By using a rubber roll having such a surface hardness, it becomes easy to maintain a uniform linear pressure applied to the molten sheet, and a bank of the molten sheet (resin pool) is provided between the metal cooling roll and the touch roll. ) Can be easily formed into a film.

  The pressure (linear pressure) when sandwiching the molten sheet is determined by the pressure for pressing the touch roll against the metal cooling roll. The linear pressure is preferably 50 N / cm or more and 300 N / cm or less, and more preferably 100 N / cm or more and 250 N / cm or less. By setting the linear pressure within the above range, it becomes easy to produce an original film of polypropylene resin while maintaining a constant linear pressure without forming a bank.

  When sandwiching a biaxially stretched film of a thermoplastic resin together with a molten sheet of polypropylene resin between a metal cooling roll and a touch roll, the thermoplastic resin constituting the biaxially stretched film is a polypropylene resin and Any resin that does not strongly heat-seal can be used. Specific examples include polyester, polyamide, polyvinyl chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and polyacrylonitrile. Among these, polyesters that have little dimensional change due to humidity, heat, and the like are most preferable. In this case, the thickness of the biaxially stretched film is usually about 5 to 50 μm, preferably 10 to 30 μm.

  In this method, the distance (air gap) from the lip of the T die to the pressure between the metal cooling roll and the touch roll is preferably 200 mm or less, and more preferably 160 mm or less. The molten sheet extruded from the T-die is stretched from the lip to the roll, and orientation tends to occur. By shortening the air gap as described above, a film having a smaller orientation can be obtained. The lower limit value of the air gap is determined by the diameter of the metal cooling roll to be used, the diameter of the touch roll, and the tip shape of the lip to be used, and is usually 50 mm or more.

  The processing speed for producing a polypropylene resin raw film by this method is determined by the time required for cooling and solidifying the molten sheet. When the diameter of the metal cooling roll to be used is increased, the distance at which the molten sheet is in contact with the cooling roll becomes longer, so that production at a higher speed is possible. Specifically, when a 600 mmφ metal cooling roll is used, the processing speed is about 5 to 20 m / min at the maximum.

  The molten sheet sandwiched between the metal cooling roll and the touch roll is cooled and solidified by contact with the roll. And after slitting an edge part as needed, it is wound up by a winder and turns into a raw film. Under the present circumstances, in order to protect the surface until it uses a raw film, you may wind in the state which bonded the surface protection film which consists of another thermoplastic resin to the single side | surface or both surfaces. When a molten sheet of polypropylene resin is sandwiched between a metal cooling roll and a touch roll together with a biaxially stretched film made of a thermoplastic resin, the biaxially stretched film is used as one surface protective film. You can also.

(Method for producing retardation film)
The retardation film used in the present invention can be produced by laterally stretching a raw film made of polypropylene resin as described above. Here, transverse stretching refers to stretching a long film unwound from a roll in the width direction (lateral direction).

The transverse stretching usually has the following steps.
(A) A preheating step of preheating the raw film at a temperature near the melting point of the polypropylene resin;
(B) a stretching step of stretching the preheated film in the transverse direction at a temperature lower than the preheating temperature; and
(C) The heat setting process which heat-sets the film extended | stretched to the horizontal direction.

  As a typical transverse stretching method, there is a tenter method. The tenter method is a method in which an original film, which is fixed at both ends in the film width direction with a chuck, is stretched in an oven with an increased chuck interval. A stretching machine (tenter stretching machine) used for the tenter method is usually provided with a mechanism capable of independently adjusting the temperatures in the zone for performing the preheating step, the zone for performing the stretching step, and the zone for performing the heat setting step. By performing transverse stretching using such a tenter stretching machine, a retardation film having excellent axial accuracy and a uniform retardation can be obtained.

  The pre-heating step (A) of transverse stretching is a step that is installed before the step of stretching the film in the width direction, and is a step of heating the film to a temperature sufficient to stretch the film. The preheating temperature in the preheating step means an atmospheric temperature in a zone where the oven preheating step is performed, and a temperature near the melting point of the polypropylene resin film to be stretched is adopted. The residence time in the preheating step of the stretched film is preferably 30 to 120 seconds. When the residence time in this preheating process is less than 30 seconds, stress is dispersed when the film is stretched in the stretching process, which adversely affects the axial accuracy and retardation uniformity as the retardation film. There is a possibility, and when the residence time exceeds 120 seconds, the film receives heat more than necessary, and the film may partially melt and draw down (drip down). The residence time in the preheating step is more preferably 30 to 60 seconds.

The stretching step (B) of transverse stretching is a step of stretching the film in the width direction. The stretching temperature in this stretching step is usually lower than the preheating temperature. The stretching temperature in the stretching process means the atmospheric temperature in the zone where the oven stretching process is performed. By stretching the preheated film at a temperature lower than that in the preheating step, the film can be stretched uniformly, and as a result, a retardation film excellent in optical axis and retardation uniformity can be obtained. The stretching temperature is preferably 5 to 20 ° C lower than the preheating temperature in the preheating step, and more preferably 7 to 15 ° C. The draw ratio at this time may be appropriately selected from the range of about 3 to 10 times in the direction in which the optical axis is expressed (the direction of the slow axis), preferably 3 according to the required retardation value. It is a range of ~ 6 times. With the draw ratio at this time more than three times, the N _z coefficient of the can be in the range of 0.9 to 1.1. On the other hand, if the draw ratio becomes too large, the uniformity of the retardation value may be impaired, so it is preferable to limit it to about 10 times.

  The transverse stretching heat setting step (C) is a step of allowing the film to pass through a predetermined temperature zone in the oven while maintaining the film width at the end of the stretching step. In order to effectively improve the stability of optical properties such as phase difference and optical axis of the film, the heat setting temperature is from 5 ° C. lower than the stretching temperature in the stretching step to 30 ° C. higher than the stretching temperature. It is preferable to be within the range.

  The transverse stretching process may further include a thermal relaxation process. In the tenter method, this thermal relaxation process is usually performed between the stretching process and the heat setting process, and the thermal relaxation zone is usually provided so that the temperature can be set independently of the other zones. It is. Specifically, in the thermal relaxation process, after the film is stretched to a predetermined width in the stretching process, the chuck interval is narrowed by a few percent in order to remove unnecessary strain, and is usually smaller than the interval at the end of stretching. Narrowing by about 0.5 to 7% is performed.

<Primer layer>
The primer layer (primer layer 30 in FIG. 1) constituting the retardation film with an adhesive layer of the present invention is composed of a copolymer containing the following monomer units (a), (b) and (c). By interposing such a primer layer, the adhesion between the retardation film and the pressure-sensitive adhesive layer can be improved.
(A) The following general formula (I):
_{CH 2 = CH-R (I} )
A monomer unit derived from a vinyl compound represented by
(B) Monomer units derived from unsaturated carboxylic acids.
(C) A monomer unit derived from a linear ethylene chain hydrocarbon having a double bond at the 1,2-position.

  The substituent R in the vinyl compound represented by the general formula (I) constituting the monomer unit (a) is a cycloalkyl group, a secondary alkyl group, or a tertiary alkyl group. As the cycloalkyl group, a cycloalkyl group having 3 to 16 members is preferable, and a cycloalkyl group having 3 to 20 members and having 3 to 10 members is more preferable. The secondary alkyl group is preferably a secondary alkyl group having 3 to 20 carbon atoms, and the tertiary alkyl group is preferably a tertiary alkyl group having 4 to 20 carbon atoms. Among these, the substituent R is particularly preferably a cycloalkyl group having 3 to 20 carbon atoms and a cycloalkyl group having 3 to 20 carbon atoms or a tertiary alkyl group having 4 to 20 carbon atoms.

  Specific examples of the vinyl compound represented by the general formula (I) include vinylcyclopropane, vinylcyclobutane, vinylcyclopentane, vinylcyclohexane, vinylcycloheptane, vinylcyclooctane, 3-methyl-1-butene, and 3-methyl. -1-pentene, 3-methyl-1-hexene, 3-methyl-1-heptene, 3-methyl-1-octene, 3,3-dimethyl-1-butene, 3,3-dimethyl-1-pentene, 3 , 3-dimethyl-1-hexene, 3,3-dimethyl-1-heptene, 3,3-dimethyl-1-octene, 3,4-dimethyl-1-pentene, 3,4-dimethyl-1-hexene, 3, , 4-dimethyl-1-heptene, 3,4-dimethyl-1-octene, 3,5-dimethyl-1-hexene, 3,5-dimethyl-1-heptene, 3, 5-dimethyl-1-octene, 3,6-dimethyl-1-heptene, 3,6-dimethyl-1-octene, 3,7-dimethyl-1-octene, 3,3,4-trimethyl-1-pentene, 3,3,4-trimethyl-1-hexene, 3,3,4-trimethyl-1-heptene, 3,3,4-trimethyl-1-octene, 3,4,4-trimethyl-1-pentene, 3, 4,4-trimethyl-1-hexene, 3,4,4-trimethyl-1-heptene, 3,4,4-trimethyl-1-octene, 5-vinyl-2-norbornene, 1-vinyladamantane, 4-vinyl Examples include -1-cyclohexene.

  Among these, from the viewpoint of improving the adhesion between the retardation film and the pressure-sensitive adhesive layer, the vinyl compound represented by the general formula (I) is vinylcyclopentane, vinylcyclohexane, vinylcycloheptane, vinylcyclooctane, 5 -Vinyl-2-norbornene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-methyl-1-hexene, 3,3-dimethyl-1-butene, 3,3-dimethyl-1-pentene 3,4-dimethyl-1-pentene, 3,5-dimethyl-1-hexene, 3,3,4-trimethyl-1-pentene, 3,4,4-trimethyl-1-pentene, More preferably, vinylcyclohexane, vinylnorbornene, 3-methyl-1-butene, 3-methyl-1-pentene, 3,3-dimethyl-1-butene, 3, - dimethyl-1-pentene, a 3,3,4-trimethyl-1-pentene, more preferably, vinyl cyclohexane, 3,3-dimethyl-1-butene. The most preferred vinyl compound is vinylcyclohexane.

  Examples of the unsaturated carboxylic acids constituting the monomer unit (b) include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, nadic acid, and methyl. Unsaturated carboxylic acids such as nadic acid, hymic acid, angelic acid, tetrahydrophthalic acid, sorbic acid, mesaconic acid; maleic anhydride, itaconic anhydride, citraconic anhydride, nadic anhydride, methyl nadic anhydride, hymic anhydride Unsaturated carboxylic acid anhydrides; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylic acid-n-propyl, methacrylic acid-n-propyl, acrylic acid-i-propyl, methacrylic acid-i- Propyl, acrylic acid-n-butyl, methacrylic acid-n-butyl , -I-butyl acrylate, -i-butyl methacrylate, -t-butyl acrylate, -t-butyl methacrylate, hydroxymethyl acrylate, -t-butyl methacrylate, tert-butyl methacrylate, Hydroxymethyl acrylate, hydroxymethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acrylonitrile, Acrylamide, methacrylamide, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid monomethyl ester Unsaturated carboxylic acid esters such as dimethyl itaconate; acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N, N-diethylamide, maleic acid-N-mono Butyramide, maleic acid-N, N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid-N, N-diethylamide, fumaric acid-N-monobutylamide, fumaric acid -Unsaturated carboxylic acid amides such as N, N-dibutylamide; unsaturated carboxylic acid imides such as maleimide, N-butylmaleimide and N-phenylmaleimide; unsaturated carboxylic acid halides such as maleoyl chloride; sodium acrylate, methacrylic acid Sodium, potassium acrylate And unsaturated carboxylic acid metal salts such as potassium and potassium methacrylate. Moreover, you may use combining said unsaturated carboxylic acid.

  Unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxymethyl acrylate, hydroxymethyl methacrylate, hydroxyethyl acrylate , Hydroxyethyl methacrylate, glycidyl acrylate, and glycidyl methacrylate are preferred, and maleic anhydride and hydroxyethyl methacrylate are particularly preferred.

In addition to the monomer units (a) and (b), the copolymer forming the primer layer is derived from a linear ethylene chain hydrocarbon having a double bond at the 1,2-position. Contains monomer unit (c). Here, “linear ethylene chain hydrocarbon having a double bond in the 1,2-position” means a general formula C _n H _2n (n is 2) having a carbon-carbon double bond in the 1,2-position. A linear aliphatic unsaturated hydrocarbon represented by the above integer).

  Examples of the linear ethylene chain hydrocarbon having a double bond at the 1,2-position include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-octene, Nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nanodecene, 1-eicosene, etc. Preferred are linear ethylene chain hydrocarbons having 2 to 20 carbon atoms, more preferred are ethylene, propylene, 1-butene, 1-pentene, 1-hexene and 1-octene, and even more preferred is propylene. .

  In the copolymer constituting the primer layer, the content of the monomer unit (b) is preferably 0.01 to 30 from the viewpoint of improving the adhesion between the retardation film and the pressure-sensitive adhesive layer and the gas hole resistance. It is mol%, More preferably, it is 0.05-15 mol%, More preferably, it is 0.1-10 mol%. However, all the monomer units in a copolymer shall be 100 mol%.

  In the copolymer, the content of the monomer unit (c) is 100 mol%, with the total content of the monomer unit (a) and the monomer unit (c) in the copolymer being 100 mol%. It is usually 99 mol% or less, and preferably 1 to 99 mol% (content of monomer unit (a) is 99 to 99%) from the viewpoint of improving the adhesion between the retardation film and the pressure-sensitive adhesive layer and gas hole resistance. 1 mol%), more preferably 20 to 97 mol% (content of monomer unit (a) is 80 to 3 mol%), and still more preferably 40 to 95 mol% (monomer unit ( The content of a) is from 60 to 5 mol%, particularly preferably from 60 to 92 mol% (the content of the monomer unit (a) is from 40 to 8 mol%), most preferably from 80 to 90 mol%. Mol% (content of monomer unit (a) is 20 to 10 mol%).

The content of the monomer units (a) to (c) can be determined using a ¹ H-NMR spectrum or a ¹³ C-NMR spectrum.

  The copolymer may contain monomer units other than the monomer units (a) to (c). Examples of the monomer constituting the monomer unit include cyclic olefins, vinylidene compounds represented by the following general formula (II), diene compounds, vinyl halides, vinyl alkanoates, vinyl ethers, acrylonitriles, and the like. Can be mentioned.

(Wherein R ¹ and R ² each independently represents a linear, branched or cyclic hydrocarbon group having 1 to 18 carbon atoms, etc.)
Examples of the cyclic olefin include cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3-methylcyclopentene, 4-methylcyclopentene, 3-methylcyclohexene, 2-norbornene, 5-methyl-2-norbornene, and 5-ethyl-2- Norbornene, 5-butyl-2-norbornene, 5-phenyl-2-norbornene, 5-benzyl-2-norbornene, 2-tetracyclododecene, 2-tricyclodecene, 2-tricycloundecene, 2-pentacyclo Pentadecene, 2-pentacyclohexadecene, 8-methyl-2-tetracyclododecene, 8-ethyl-2-tetracyclododecene, 5-acetyl-2-norbornene, 5-acetyloxy-2-norbornene, 5- Methoxycarbonyl-2-norbol , 5-ethoxycarbonyl-2-norbornene, 5-methyl-5-methoxycarbonyl-2-norbornene, 5-cyano-2-norbornene, 8-methoxycarbonyl-2-tetracyclododecene, 8-methyl-8- Examples include methoxycarbonyl-2-tetracyclododecene, 8-cyano-2-tetracyclododecene, and the like. More preferred cyclic olefins are cyclopentene, cyclohexene, cyclooctene, 2-norbornene, 5-methyl-2-norbornene, 5-phenyl-2-norbornene, 2-tetracyclododecene, 2-tricyclodecene, 2-tricyclo Undecene, 2-pentacyclopentadecene, 2-pentacyclohexadecene, 5-acetyl-2-norbornene, 5-acetyloxy-2-norbornene, 5-methoxycarbonyl-2-norbornene, 5-methyl-5-methoxycarbonyl 2-norbornene and 5-cyano-2-norbornene, particularly preferably 2-norbornene and 2-tetracyclododecene.

  Examples of the vinylidene compound represented by the general formula (II) include isobutene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, and 2-methyl-1-heptene. 2-methyl-1-octene, 2,3-dimethyl-1-butene, 2,3-dimethyl-1-pentene, 2,3-dimethyl-1-hexene, 2,3-dimethyl-1-heptene, 2 , 3-dimethyl-1-octene, 2,4-dimethyl-1-pentene, 2,4,4-trimethyl-1-pentene, and the like. Particularly preferred vinylidene compounds are isobutene, 2,3-dimethyl-1-butene, and 2,4,4-trimethyl-1-pentene.

  Examples of the diene compound include 1,3-butadiene, 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,5-cyclooctadiene, 2,5- Examples thereof include norbornadiene, dicyclopentadiene, 5-vinyl-2-norbornene, 5-allyl-2-norbornene, 4-vinyl-1-cyclohexene, 5-ethylidene-2-norbornene and the like. Particularly preferred diene compounds are 1,4-pentadiene, 1,5-hexadiene, 2,5-norbornadiene, dicyclopentadiene, 5-vinyl-2-norbornene, 4-vinyl-1-cyclohexene, 5-ethylidene-2- Norbornene.

  Examples of the vinyl alkanoate include vinyl acetate, vinyl propionate, and vinyl butyrate. Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, and n-butyl vinyl ether. Examples of acrylonitriles include acrylonitrile and methacrylonitrile.

  In the copolymer constituting the primer layer, the content of monomer units other than the monomer units (a) to (c) is 100 mol% of the content of all monomer units in the copolymer. Is preferably 30 mol% or less, more preferably 10 mol% or less, still more preferably 5 mol% or less, and particularly preferably 1 mol% or less.

  A known method is used as a method for producing the copolymer. For example, the copolymer is represented by the general formula (I) in the presence of a catalyst obtained by contacting isopropylidenebis (indenyl) zirconium dichloride and methylalumoxane. Examples include a method of copolymerizing a vinyl compound, the unsaturated carboxylic acid, and the linear ethylene chain hydrocarbon having a double bond at the 1,2-position. Specifically, European Patent Application Publication No. For example, the method described in the specification of No. 1219648 can be used.

  As a method for producing the copolymer, a multistage polymerization method may be used. For example, the vinyl compound represented by the general formula (I) and the linear ethylene having a double bond at the 1,2-position are used. A method of graft polymerization of the polymer obtained by copolymerization with the above-mentioned unsaturated carboxylic acid after copolymerization with a row hydrocarbon; a double bond at the 1,2-position with the unsaturated carboxylic acid; Examples thereof include a method of copolymerizing a linear ethylene series hydrocarbon having the above and then graft-polymerizing a polymer obtained by the copolymerization with a vinyl compound represented by the above general formula (I).

  As the graft polymerization method, for example, a precursor (a polymer obtained by the first-stage copolymerization) is melted, and then a monomer (a vinyl compound represented by the general formula (I), an unsaturated carboxylic acid) is used. A method of adding an acid or the like to graft polymerization; the precursor is dissolved in a solvent such as toluene or xylene, and then a monomer (a vinyl compound represented by the general formula (I), an unsaturated carboxylic acid or the like) is added. For example, a method of graft polymerization can be used. The temperature of graft polymerization is usually about 40 to 350 ° C. In the graft polymerization, a radical initiator is usually used, and the amount of the radical initiator used is usually 0.001 to 0.5 mol, preferably 0.005 to 0, per 1 kg of the precursor. .1 mole.

  Examples of the radical initiator include methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3, 3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, 2,2-bis (tert-butylperoxy) octane, n-butyl-4,4-bis (tert-butylperoxy) valerate, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, Ramentan hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, dic Milperoxide, α, α′-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5- Di (tert-butylperoxy) -3-hexyne, 1,4-bis (tert-butylperoxyisopropyl) benzene, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5 -Trimethylhexa Yl peroxide, succinic acid peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-tolunoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-n-propylperoxydicarbonate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, dimyristylperoxydicarbonate, di-2-ethoxyethylperoxydicarbonate, dimethoxyisopropylperoxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, diallyl Peroxydicarbonate, tert-butylperoxyacetate, tert-butylperoxyisobutyrate, tert-butylperoxy Valerate, tert-butylperoxyneodecanoate, cumylperoxyneodecanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butyl Peroxylaurate, tert-butylperoxybenzoate, di-tert-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di ( Benzoylperoxy) -3-hexyne, tert-butylperoxymaleic acid, tert-butylperoxyisopropyl carbonate, cumylperoxyoctoate, tert-hexylperoxyneodecanate, tert-hexylperoxypivalate, organic peroxides such as tert-butylperoxyneohexanoate, tert-hexylperoxyneohexanoate, cumylperoxyneohexanoate, acetylcyclohexylsulfonyl peroxide, tert-butylperoxyallylcarbonate; azobisiso Examples thereof include azo compounds such as butyronitrile, azobisisopropionitrile, and dimethylazoisobutyrate.

  The value of the intrinsic viscosity [η] of the copolymer constituting the primer layer is preferably 0.08 dl / g or more, more preferably 0 from the viewpoint of enhancing the adhesion between the retardation film and the pressure-sensitive adhesive layer. .10 dl / g or more, more preferably 0.15 dl / g or more, and preferably 10.0 dl / g or less, more preferably 3 from the viewpoint of improving the coatability (ease of application) of the primer. 0.0 dl / g or less, more preferably 2.0 dl / g or less.

  The primer layer can be formed by preparing a coating composition (primer) containing the copolymer and coating it on a retardation film.

  The primer used in the present invention may contain water, and includes aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane; esters such as ethyl acetate and butyl acetate; methyl ethyl ketone and methyl isobutyl ketone. Ketones such as; organic solvents such as alcohols such as methanol, isopropyl alcohol, ethylene glycol, and propylene glycol; The content of these solvents is appropriately selected depending on the intrinsic viscosity [η] of the copolymer contained in the primer, but is usually about 150 to 3000 parts by weight with respect to 100 parts by weight of the copolymer. Preferably it is 200-2000 weight part.

  Primers are phenol stabilizers, phosphite stabilizers, amine stabilizers, amide stabilizers, anti-aging agents, weathering stabilizers, anti-settling agents, antioxidants, heat stabilizers, light stabilizers, etc. Agents: Thixotropic agents, thickeners, antifoaming agents, surface conditioners, weathering agents, pigment dispersants, antistatic agents, lubricants, nucleating agents, flame retardants, oil agents, dyes, etc .; titanium oxide (rutile type) ), Transition metal compounds such as zinc oxide, pigments such as carbon black; glass fiber, carbon fiber, potassium titanate fiber, wollastonite, calcium carbonate, calcium sulfate, talc, glass flake, barium sulfate, clay, kaolin, fine Filling with inorganic and organic powder silica, mica, calcium silicate, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, alumina, celite, etc. Or the like may also contain. The primer may contain a thermosetting resin such as a polyester resin, a polyurethane resin, a polyacrylic resin, or a melamine resin.

  The primer used in the present invention may be in a form in which a copolymer, a stabilizer, an additive, a pigment, a filler and the like are dissolved in a solvent, and all or any of these are dispersed. It may be in the form.

  The method for applying the primer to the retardation film is not particularly limited. For example, a spin coating method, a bar coating method, a roll coating method, a curtain coating method, and a die coating method such as slot coating or extrusion coating are adopted. can do. After applying the primer, it is preferable to incorporate a solvent removal (drying) step by a method such as heating with a heater or blowing warm air, and removing the solvent by appropriately drying.

  When the primer is applied to a retardation film made of a polypropylene resin, it is preferable to subject the surface of the retardation film to corona treatment. Thereby, the adhesiveness of the primer layer obtained and the phase difference film which consists of polypropylene resin can further be improved.

  The thickness of the primer layer is not particularly limited, but is preferably in the range of about 0.1 to 10 μm, and more preferably about 0.5 to 10 μm.

<Adhesive layer>
Examples of the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer 40 in FIG. 1) include pressure-sensitive adhesives based on acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and the like. Above all, like acrylic pressure-sensitive adhesives based on acrylic polymers, it has excellent optical transparency, moderate wettability and cohesion, and excellent adhesion to substrates. It is preferable to select and use one that has weather resistance, heat resistance, etc. and does not cause peeling problems such as floating and peeling under the conditions of heating and humidification.

  Examples of the acrylic base polymer contained in the acrylic pressure-sensitive adhesive include alkyl esters of acrylic acid having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, and a butyl group, and (meth) acrylic acid or (meta ) An acrylic copolymer with a functional group-containing acrylic monomer such as hydroxyethyl acrylate. The glass transition temperature of the acrylic copolymer is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. The weight average molecular weight of the acrylic copolymer is preferably 100,000 or more.

  A diffusion adhesive in which a light diffusing agent is dispersed can also be used as the adhesive that forms the adhesive layer. The light diffusing agent is for imparting light diffusibility to the pressure-sensitive adhesive layer, and may be fine particles having a refractive index different from that of the base polymer constituting the pressure-sensitive adhesive layer. Fine particles made of (polymer) can be used. Since the base polymer constituting the pressure-sensitive adhesive layer including the acrylic base polymer as described above often has a refractive index of around 1.4, the refractive index of the light diffusing agent is about 1-2. What is necessary is just to select suitably from the thing. The difference in refractive index between the base polymer constituting the pressure-sensitive adhesive layer and the light diffusing agent is usually 0.01 or more, and from the viewpoint of the brightness and visibility of the image display device, it is 0.01 or more and 0.5 or less. It is preferable to do this. The fine particles used as the light diffusing agent are preferably spherical and those close to monodisperse. For example, fine particles having an average particle diameter in the range of about 2 to 6 μm are preferably used.

  Examples of the fine particles made of an inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45).

  Examples of the fine particles made of an organic compound (polymer) include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate / styrene copolymer resin beads (refractive index). 1.50), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46) ), Silicone resin beads (refractive index 1.46), and the like.

  The blending amount of the light diffusing agent is appropriately determined in consideration of the haze value required for the pressure-sensitive adhesive layer in which it is dispersed, the brightness of the image display device to which it is applied, etc. It is about 3-30 weight part with respect to 100 weight part of base polymers which comprise an adhesive layer.

  The haze value of the pressure-sensitive adhesive layer in which the light diffusing agent is dispersed ensures the brightness of the image display device to which the retardation film with the pressure-sensitive adhesive layer or the polarizing plate using the pressure-sensitive adhesive layer is applied. From the viewpoint of making it difficult to cause occurrence, it is preferable to be in the range of 20 to 80%. The haze value is a value represented by (diffuse transmittance / total light transmittance) × 100 (%), and is measured according to JIS K 7105.

  The pressure-sensitive adhesive layer can be formed by a method in which a pressure-sensitive adhesive solution mainly composed of the base polymer as described above is applied on the primer layer and dried. After forming the pressure-sensitive adhesive layer by applying and drying the adhesive solution, this film with the pressure-sensitive adhesive layer may also be formed by a method of bonding to the surface of the primer layer so that the pressure-sensitive adhesive layer side becomes the bonding surface Can do. The primer layer surface on which the pressure-sensitive adhesive layer is formed is preferably subjected to corona discharge treatment in advance. Thereby, the adhesiveness of a primer layer and an adhesive layer can be improved. In the case where an elliptically polarizing plate is produced by laminating a linearly polarizing plate on the side opposite to the primer layer side of the retardation film (the elliptically polarizing plate will be described later), the formation of the pressure-sensitive adhesive layer is carried out by retardation. You may carry out after laminating | stacking a linear polarizing plate on a film.

  Although the thickness of an adhesive layer is determined according to the adhesive force etc., it is about 1-40 micrometers normally. In order to obtain a thin retardation film with an adhesive layer and an elliptically polarizing plate using the same without impairing properties such as processability and durability, the thickness of the adhesive layer should be about 3 to 25 μm. preferable. In addition, by setting the thickness of the pressure-sensitive adhesive layer to about 3 to 25 μm, it is possible to maintain brightness when the image display device is viewed from the front or from an oblique direction, and to prevent blurring or blurring of the display image. it can.

<< Ellipse Polarizing Plate >>
The retardation film with an adhesive layer of the present invention can be suitably applied to an elliptically polarizing plate. In the elliptically polarizing plate of the present invention, the retardation film with an adhesive layer may function as a quarter wavelength plate or a half wavelength plate. FIG. 2 is a schematic cross-sectional view (FIG. 2 (A)) showing a preferred example of the elliptically polarizing plate of the present invention and a schematic view (FIG. 2 (B)) for explaining the relationship between the axial angles.

  The elliptically polarizing plate 52 shown in FIG. 2 is obtained by laminating a linearly polarizing plate 50 on the surface opposite to the adhesive layer of the retardation film 10 with an adhesive layer (that is, on a retardation film made of polypropylene resin). Do it. In this example, the phase difference film 10 with an adhesive layer functions as a quarter wave plate. The quarter-wave plate functions to convert light that is incident as linearly polarized light into elliptically polarized light such as circularly polarized light, and light that is incident as elliptically polarized light such as circularly polarized light into linearly polarized light. Have

Here, when the retardation film with a pressure-sensitive adhesive layer of the present invention is used as a quarter-wave plate, the in-plane retardation value R ₀ is preferably in the range of 70 to 160 nm, more preferably 80 to 150 nm. More preferably, it is in the range.

  A linearly polarizing plate is an optical member provided with a function of absorbing linearly polarized light having a vibration surface in a certain direction and transmitting linearly polarized light having a vibration surface in a direction orthogonal thereto, and is generally used in this field. You can use what you have. Specifically, a polyvinyl alcohol linear polarizing plate in which a transparent protective layer is formed on at least one surface of a polarizing film made of a polyvinyl alcohol resin film is common. A function of absorbing linearly polarized light having a vibrating surface in a certain direction and transmitting linearly polarized light having a vibrating surface in a direction orthogonal to the above by adsorbing and orienting a dichroic dye on a polyvinyl alcohol resin film. Can be granted. As the dichroic dye, iodine or a dichroic organic dye is used. A polarizing film comprising a polyvinyl alcohol resin film can be obtained by subjecting the polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment after dyeing.

  Examples of the transparent protective layer used in the linear polarizing plate include films of acetyl cellulose resins typified by triacetyl cellulose (TAC) and diacetyl cellulose, which have been conventionally used as protective layers for polarizing films. In addition, a film of a cyclic polyolefin resin represented by a norbornene resin, a film of a polypropylene resin, a film of a polyethylene terephthalate resin, a film of poly (meth) acrylate, and the like may be used.

  In the elliptically polarizing plate shown in FIG. 2 (A), with reference to FIG. 2 (B), with the absorption axis 22 of the linearly polarizing plate 50 as a reference, the counterclockwise direction is positive and a quarter wavelength plate is used. It arrange | positions so that the angle (theta) which reaches the in-plane slow axis 12 of the phase difference film 10 with an adhesive layer may be 40-50 degree | times, Preferably it is substantially 45 degree | times so that it may function as a substantially circularly-polarizing plate. Become. Or, with reference to the absorption axis 22 of the linear polarizing plate 50, the angle θ reaching the in-plane slow axis 12 of the phase difference film 10 with the pressure-sensitive adhesive layer that is a quarter-wave plate, with the counterclockwise direction being positive, Even if it is disposed at 130 to 140 degrees, preferably approximately 135 degrees, it also functions as a substantially circularly polarizing plate. Hereinafter, when the angle is expressed, the counterclockwise rotation with respect to the absorption axis is positive as in the description here.

  FIG. 3 is a schematic cross-sectional view (FIG. 3 (A)) showing another preferred example of the elliptically polarizing plate of the present invention and a schematic view (FIG. 3 (B)) for explaining the relationship between the axial angles. The elliptically polarizing plate 55 shown in FIG. 3 is on the surface opposite to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-equipped retardation film 10 that is a quarter-wave plate (that is, on a phase difference film made of polypropylene resin). Further, a half-wave plate 25 is laminated, and a linearly polarizing plate 50 is laminated on the half-wave plate 25. The half-wave plate 25 has a function of rotating the direction of linearly polarized light.

In the elliptically polarizing plate shown in FIG. 3, the above-mentioned ones can be used as the transparent protective layer used for the linearly polarizing plate and the linearly polarizing plate. Moreover, as a half-wave plate, a conventionally well-known thing can be used and the phase difference film with an adhesive layer of this invention may be used. Examples of conventionally known half-wave plates include a retardation film made of a cyclic polyolefin resin, a retardation film made of a polycarbonate resin, and the like. When the retardation film with an adhesive layer of the present invention is used as a half-wave plate, the in-plane retardation value R ₀ is preferably in the range of 240 to 400 nm, and more preferably in the range of 260 to 330 nm. It is more preferable.

  As shown in FIG. 3A, by using a combination of a quarter-wave plate and a half-wave plate, a laminate of these wave plates has a wide wavelength range in the visible light region, that is, a wide band. An elliptical polarizing plate that functions as a quarter-wave plate and has a linear polarizing plate laminated on its half-wave plate side can convert linearly polarized light into circularly polarized light and circularly polarized light into linearly polarized light over a wide band. become. Furthermore, by comprising in this way, the angle dependence of the antireflection effect can also be reduced.

  In the elliptically polarizing plate shown in FIG. 3A, with reference to the absorption axis 22 of the linearly polarizing plate 50, the in-plane slow axis 17 of the half-wave plate 25 is referred to with reference to FIG. The reaching angle φ is 10 to 20 degrees, preferably about 15 degrees, and the in-plane retardation of the retardation film 10 with an adhesive layer that is a quarter-wave plate from the in-plane slow axis 17 of the half-wave plate 25. By arranging so that the angle Ψ reaching the axis 12 is 55 to 65 degrees, preferably approximately 60 degrees, it functions almost as a circularly polarizing plate. Alternatively, on the basis of the absorption axis 22 of the linearly polarizing plate 50, the angle φ reaching the in-plane slow axis 17 of the half-wave plate 25 is 100 to 110 degrees, preferably about 105 degrees. The angle Ψ from the in-plane slow axis 17 to the in-plane slow axis 12 of the retardation film 10 with a pressure-sensitive adhesive layer, which is a quarter wavelength plate, is 55 to 65 degrees, preferably about 60 degrees. By doing so, it will still function as a circularly polarizing plate. The latter relationship (the angle φ from the absorption axis 22 of the linear polarizing plate 50 to the in-plane slow axis 17 of the half-wave plate 25 is 100 to 110 degrees) is shown in FIG. This corresponds to a state in which “axis 22” is read as “transmission axis of linearly polarizing plate”. In the linear polarizing plate, the absorption axis and the transmission axis are in a relationship orthogonal in the plane.

  In production of the elliptically polarizing plate, for example, an adhesive layer can be used for bonding between the wave plate and the linear polarizing plate and bonding between the wave plates (quarter wave plate and half wave plate). . As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, those described above can be used, and among them, a pressure-sensitive adhesive mainly composed of an acrylic polymer excellent in transparency and durability is preferably used. The thickness of the pressure-sensitive adhesive layer is usually in the range of 5 to 50 μm.

  The elliptically polarizing plate of this invention can be set as the structure provided with the adhesive layer derived from the phase difference film with an adhesive on the surface on the opposite side (1/4 wavelength plate side) from a linearly-polarizing plate. The said adhesive layer can be used suitably for bonding with a liquid crystal cell.

<< Liquid Crystal Display >>
FIG. 4 is a schematic cross-sectional view showing the configuration of an example of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 4 is an example in which the elliptically polarizing plate 52 shown in FIG. 2 is arranged on both sides of the liquid crystal cell 60. Specifically, the backlight 70 and the elliptically polarizing plate 52 are arranged from the backlight side. The liquid crystal cell 60 and the elliptically polarizing plate 52 are arranged in this order. The two elliptically polarizing plates 52 are bonded using the pressure-sensitive adhesive layer so that the phase difference film with pressure-sensitive adhesive layer 10 side that is a quarter wavelength plate faces the liquid crystal cell 60. The two elliptically polarizing plates 52 are arranged so that the absorption axes of the linearly polarizing plates 50 are orthogonal to each other.

  FIG. 5 is a schematic cross-sectional view showing the configuration of another example of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 5 is an example in which the elliptically polarizing plate 55 shown in FIG. 3 is arranged on both sides of the liquid crystal cell 60. Specifically, the backlight 70 and the elliptically polarizing plate 55 are arranged from the backlight side. The liquid crystal cell 60 and the elliptically polarizing plate 55 are arranged in this order. The two elliptically polarizing plates 55 are bonded using the pressure-sensitive adhesive layer so that the phase difference film 10 with the pressure-sensitive adhesive layer, which is a quarter wavelength plate, faces the liquid crystal cell 60. The two elliptical polarizing plates 55 are arranged so that the absorption axes of the linear polarizing plates 50 are orthogonal to each other.

  Note that the backlight 70 is provided when the liquid crystal display device is a transmissive or transflective type, and may be omitted in the case of a reflective liquid crystal display device. 4 and 5, the elliptically polarizing plate of the present invention is used on both surfaces of the liquid crystal cell. However, the present invention is not limited to this, and the elliptically polarizing plate of the present invention is used on one side of the liquid crystal cell. Another polarizing plate may be bonded to one surface.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, “parts” and “%” representing the amount used or content are based on weight unless otherwise specified.

(Production Example 1: Production of retardation film)
A propylene / ethylene random copolymer (“Sumitomo Nobrene W151” manufactured by Sumitomo Chemical Co., Ltd.) containing about 5% ethylene unit was formed into a raw film made of polypropylene resin having a thickness of 40 μm. By uniaxially stretching the original film, a uniaxial retardation film was obtained. This retardation film had R ₀ = 90 nm, R _th = 45 nm, and a thickness of 9 μm. Next, the trade name “Tretec 7332”, which is a self-adhesive surface protective film manufactured by Toray Film Processing Co., Ltd., was bonded to one side of the retardation film made of this polypropylene resin.

(Production Example 2: Preparation of primer)
Maleic anhydride-modified ethylene-vinylcyclohexane copolymer having a maleic anhydride unit content of 2.6 mol%, a vinylcyclohexane unit content of 12.7 mol%, and an ethylene unit content of 84.7 mol% 10 parts by weight of the coalescence was dissolved in 90 parts by weight of toluene to obtain a primer.

<Example 1>
(A) Formation of Primer Layer on Retardation Film On the surface opposite to the surface on which the surface protective film of the retardation film made of the polypropylene resin obtained in Production Example 1 is laminated, Corona discharge treatment was performed at 9 kJ / m ² . Within 5 minutes after corona discharge treatment, the primer obtained in Production Example 2 was applied to the corona-treated surface using a Mayer bar (# 7), and then dried in an oven at 80 ° C. for 3 minutes. A primer layer having a thickness of 0.8 μm was formed on the retardation film.

(B) Production of elliptical polarizing plate A polarizing plate (SRW062 manufactured by Sumitomo Chemical Co., Ltd.) is prepared in which protective films made of triacetylcellulose are bonded to both surfaces of a polarizing film in which iodine is adsorbed and oriented on polyvinyl alcohol. Then, a urethane acrylate-based pressure-sensitive adhesive (NS300MP sold by Lintec Co., Ltd.) was bonded to one surface to prepare a polarizing plate with a pressure-sensitive adhesive. On the other hand, the surface protective film is peeled off from the retardation film with a primer layer produced in the above (a), and the surface (polypropylene resin surface) is subjected to a corona discharge treatment with an integrated irradiation amount of 15.9 kJ / m ² to obtain a corona discharge treatment. Within 5 minutes, the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive prepared above was bonded to the corona-treated surface within 5 minutes. Thereafter, the primer layer was also subjected to corona discharge treatment with an integrated dose of 15.9 kJ / m ² . Within 5 minutes after this corona discharge treatment, an acrylic sheet-like pressure-sensitive adhesive (P3132 sold by Lintec Corporation) was bonded to the corona-treated surface to obtain an elliptical polarizing plate with a pressure-sensitive adhesive layer. .

<Comparative Example 1>
The surface of the retardation film obtained in Production Example 1 on the side opposite to the side on which the surface protective film was laminated was subjected to corona discharge treatment with an integrated dose of 15.9 kJ / m ² . Within 5 minutes after corona discharge treatment, an acrylic sheet-like adhesive (P3132 sold by Lintec Corporation) is bonded to the corona-treated surface, and a retardation film with an adhesive layer (no primer layer) )

Next, a polarizing plate (SRW062 manufactured by Sumitomo Chemical Co., Ltd.) in which a protective film made of triacetyl cellulose is bonded to both sides of a polarizing film in which iodine is adsorbed and oriented on polyvinyl alcohol is prepared on one side. Then, a urethane acrylate-based sheet-like pressure-sensitive adhesive (NS300MP sold by Lintec Corporation) was bonded to produce a pressure-sensitive adhesive-attached polarizing plate. On the other hand, the surface protective film is peeled off from the above retardation film with an adhesive layer, and the surface (polypropylene resin surface) is subjected to a corona discharge treatment with an integrated irradiation amount of 15.9 kJ / m ² , and within 5 minutes after the corona discharge treatment. The adhesive layer of the polarizing plate with the adhesive prepared above was bonded to the corona-treated surface to obtain an elliptical polarizing plate with an adhesive layer.

  About the elliptically polarizing plate with an adhesive layer of the said Example and comparative example, the thickness was measured using the digital length measuring instrument "MH-15M" by Nikon Corporation. The results are shown in Table 1. Moreover, the following test was done in order to evaluate the adhesiveness with an adhesive layer, and the peelability of the adhesive layer bonded by the glass plate.

(1) Adhesion test with pressure-sensitive adhesive layer Surface from retardation film with primer layer obtained in (a) of Example 1 or retardation film (without primer layer) having the surface protective film used in Comparative Example 1 The protective film was peeled off, and the surface (polypropylene resin surface) was subjected to corona discharge treatment under the condition of an integrated irradiation amount of 15.9 kJ / m ² . Separately, a corona discharge treatment was performed on one surface of a biaxial thermoplastic saturated norbornene resin film (ZB0555124 manufactured by Optes Co., Ltd.) under the condition of an integrated irradiation amount of 15.9 kJ / m ² . Within 10 minutes after the corona discharge treatment to this norbornene-based resin film, an active energy ray-curable resin composition containing an epoxy compound is applied to the corona-treated surface, the coated surface side, and the position with the primer layer. The phase difference film or the corona-treated surface of the phase difference film not having the primer layer was bonded, and using an ultraviolet irradiation device manufactured by FUSION, ultraviolet rays were irradiated under conditions of an output of 500 mW and an irradiation amount of 1500 mJ, and cured.

Next, for the phase difference film with a primer layer, on the surface of the primer layer, for the phase difference film having no primer layer, the surface of the phase difference film is subjected to a corona discharge treatment with an integrated irradiation amount of 15.9 kJ / m ² , Within 5 minutes after corona discharge treatment, an acrylic sheet-like adhesive (P3132 sold by Lintec Co., Ltd.) is bonded to the corona-treated surface to produce a retardation film with an adhesive, The film was allowed to stand for 1 day in an atmosphere having a temperature of 23 ° C. and a relative humidity of 60% to obtain an adhesive evaluation film. This evaluation film is a thermoplastic saturated norbornene resin film / cured layer of a curable resin composition / retardation film / primer layer / adhesive layer (Example 1) or a thermoplastic saturated norbornene resin film / curable resin composition. The cured product layer / retardation film / adhesive layer (Comparative Example 1) of the product. From this adhesion evaluation film, a sample having a width of 25 mm and a length of about 200 mm was cut, and an adhesion strength evaluation device manufactured by Nippon System Group Co., Ltd. was used to evaluate the adhesion strength at three points in the length direction. The evaluation uses a styrene rubber with a hardness of 60 degrees, and the pressure-sensitive adhesive layer peels off from the retardation film when the sample is slid 20 times in a certain direction of 25 mm width while being pressed with a pressing force of 0.4 MPa. The three-point average of the obtained length was determined as the peel distance. The measurement was performed in an atmosphere at a temperature of 23 ° C. and a relative humidity of 60%. The results are shown in Table 1.

(2) Peelability test when affixed to a glass plate From the film for adhesion evaluation prepared in the above (1) adhesion test, a sample having a width of 25 mm and a length of about 200 mm was cut, and the pressure-sensitive adhesive layer surface was soda. After being bonded to glass, a pressure treatment was performed at a pressure of 5 kgf / cm ² and a temperature of 50 ° C. for 20 minutes in an autoclave, and then left for 1 day in an atmosphere of a temperature of 23 ° C. and a relative humidity of 60%. Then, using a universal tensile testing machine (AG-1, manufactured by Shimadzu Corporation), in the atmosphere of a temperature of 23 ° C. and a relative humidity of 60%, grab one end in the length direction of the sample and crosshead speed (peeling speed) ) A 90 ° peel test was performed at 200 mm / min. Whether or not the pressure-sensitive adhesive remains on the surface of the glass plate after peeling was visually observed and evaluated according to the following criteria. The results are shown in Table 1.

<Evaluation criteria for peelability test>
○: The retardation film can be peeled off without the adhesive remaining on the glass plate.

  X: The adhesive layer remains on the glass plate after peeling.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a cross-sectional schematic diagram which shows a preferable example of the phase difference film with an adhesive layer of this invention. It is the schematic for demonstrating the cross-sectional schematic diagram which shows a preferable example of the elliptically polarizing plate of this invention, and its axial angle. It is the schematic for demonstrating the cross-sectional schematic diagram which shows another preferable example of the elliptically polarizing plate of this invention, and its axial angle. It is a cross-sectional schematic diagram which shows a structure of an example of the liquid crystal display device of this invention. It is a cross-sectional schematic diagram which shows the structure of another example of the liquid crystal display device of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Retardation film with adhesive layer, 12 1/4 wavelength plate in-plane slow axis, 17 1/2 wavelength plate in-plane slow axis, 20 retardation film, 22 absorption axis, 25 1/2 wavelength plate , 30 primer layer, 40 pressure-sensitive adhesive layer, 50 linearly polarizing plate, 52, 55 elliptically polarizing plate, 60 liquid crystal cell, 70 backlight.

Claims (8)

A retardation film made of a polypropylene resin, a primer layer laminated on the surface of the retardation film, and an adhesive layer laminated on the surface of the primer layer,
The primer layer is
(A) The following general formula (I):
_{CH 2 = CH-R (I} )
(In the general formula (I), R represents a cycloalkyl group, a secondary alkyl group, or a tertiary alkyl group). A monomer unit derived from a vinyl compound represented by
(B) monomer units derived from unsaturated carboxylic acids, and
(C) a monomer unit derived from a linear ethylene chain hydrocarbon having a double bond at the 1,2-position,
A retardation film with a pressure-sensitive adhesive layer comprising a copolymer comprising   When the content of all monomer units in the copolymer constituting the primer layer is 100 mol%, the content of the monomer unit (b) in the copolymer is 0.01 to 30 mol%. The retardation film with an adhesive layer according to claim 1.   The retardation film with an adhesive layer according to claim 1, wherein the vinyl compound represented by the general formula (I) is vinylcyclohexane. The retardation film is made of a copolymer of propylene and ethylene,
Content of the monomer unit derived from the said ethylene is 10 weight% or less, The phase difference film with an adhesive layer in any one of Claims 1-3.   The said phase difference film is a quarter wavelength plate, The phase difference film with an adhesive layer in any one of Claims 1-4.   An elliptically polarizing plate comprising the retardation film with a pressure-sensitive adhesive layer according to claim 1 laminated on a polarizing plate.   The elliptically polarizing plate according to claim 6, further comprising a half-wave plate between the retardation film and the polarizing plate.   A liquid crystal display device comprising: a liquid crystal cell; and the elliptically polarizing plate according to claim 6 or 7 laminated on one side or both sides of the liquid crystal cell.

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