JP2009210878A - Retardation film with adhesive layer, and elliptical polarizing plate and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retardation film with adhesive layer which is improved in adhesion between the retardation film made of a polypropylene resin and the adhesive layer. <P>SOLUTION: The retardation film with adhesive layer includes the retardation film made of the polypropylene resin, a primer layer and the adhesive layer, formed in this order. The primer layer comprises a modified polyolefin resin modified with an unsaturated polycarboxylic acid or its derivatives and with a (meth)acrylic acid or its derivatives and having a weight average molecular weight of 15,000 to 150,000. The retardation film is made of a propylene/ethylene copolymer containing up to 10 wt.% ethylene units. The retardation film of the retardation film with an adhesive layer is preferably a quarter-wave plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a retardation film made of polypropylene resin, and an elliptically polarizing plate using the retardation film, and in particular, a retardation film with an adhesive layer in which a specific primer layer is laminated on a retardation film made of polypropylene resin, and the same The present invention relates to an elliptically polarizing plate and a liquid crystal display device.

  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 of various modes have been proposed, and problems with liquid crystal displays such as response speed, contrast, and narrow 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 method of expanding the viewing angle 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 plastic forming the birefringent film include polycarbonate, polystyrene, polymethyl methacrylate, polyolefin, and polyamide.

  As a retardation film of a polyolefin resin, an amorphous cyclic polyolefin resin, which is also called an alicyclic polyolefin or a norbornene resin, is relatively excellent in heat resistance and moisture resistance, excellent in transparency, and The phase difference value is widely used because it can be adjusted relatively easily.

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 11-149015) shows an example in which a λ / 2 stretched film or a λ / 4 stretched film is produced from a cyclic polyolefin film. Patent Document 2 (Japanese Patent Laid-Open No. 2007-286615) discloses that a polypropylene resin is applied to a retardation film. However, non-polar polyolefin resins are often inferior in adhesive strength with pressure-sensitive adhesives, and therefore need to be improved.

On the other hand, in Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-277617), a polyolefin resin modified with an unsaturated polycarboxylic acid or a derivative thereof and (meth) acrylic acid or a derivative thereof is protected with a polypropylene resin or the like. Application to a binder composition for cosmetic purposes is described.
Japanese Patent Laid-Open No. 11-149015 JP 2007-286615 A JP 2004-277617 A

  In the retardation film made of polypropylene resin, because it is inferior in adhesiveness with the pressure-sensitive adhesive as compared with the cyclic polyolefin-based resin, when peeling the optical member bonded with the optical film such as the polarizing plate and the retardation film from the liquid crystal cell, In some cases, there was a problem such as adhesive residue. In order to solve such problems, an object of the present invention is to provide a retardation film with a pressure-sensitive adhesive layer in which the adhesiveness between the retardation film made of polypropylene resin and the pressure-sensitive adhesive is improved. Another object of the present invention is to provide an elliptically polarizing plate using the retardation film with an adhesive layer. A further object of the present invention is to provide a liquid crystal display device using the elliptically polarizing plate.

  In the present invention, a retardation film made of polypropylene resin, a primer layer, and an adhesive layer are formed in this order, and the primer layer is modified with unsaturated polycarboxylic acid or a derivative thereof, and (meth) acrylic acid or a derivative thereof. And a retardation film with a pressure-sensitive adhesive layer, which is a modified polyolefin resin having a weight average molecular weight of 15,000 to 150,000.

  The retardation film made of the polypropylene resin is preferably composed of a copolymer of propylene and ethylene containing 10% by weight or less of ethylene units. Moreover, it is preferable that the said phase difference film of the said phase difference film with an adhesive layer is a quarter wavelength plate.

  The present invention relates to an elliptically polarizing plate in which the 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 elliptically polarizing plate. Another embodiment of the present invention is a liquid crystal display device in which the elliptically polarizing plate is laminated on at least one side of a liquid crystal cell.

  The composite polarizing plate using a retardation film made of polypropylene resin has low adhesion between the retardation film made of polypropylene resin and the pressure-sensitive adhesive. Although it may remain on the glass substrate, an elliptical polarizing plate using a retardation film comprising a polypropylene resin according to the present invention, a primer resin, and a retardation film with an adhesive layer in which an adhesive layer is formed in this order, Since the adhesiveness between the retardation film made of polypropylene resin and the pressure-sensitive adhesive layer is improved, the pressure-sensitive adhesive does not remain on the glass substrate.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a retardation film with an adhesive layer according to the present invention. In the retardation film 10 with an adhesive layer of the present invention, the primer layer 30 and the adhesive layer 40 are formed in this order on one surface of the retardation film 20 made of polypropylene resin.

[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. For this reason, the retardation film which has a desired retardation value with a thin film thickness can be obtained.

The polypropylene resin, the difference (birefringence) △ n ₄₀₀ between the maximum refractive index and the minimum refractive index in the plane at a wavelength of 400 nm, the difference (birefringence between the maximum refractive index and the minimum refractive index in the plane at a wavelength of 500nm ) Since the ratio of Δn ₅₀₀ (Δn ₄₀₀ / Δn ₅₀₀ ) is less than 1.05, when a half-wave plate and a quarter-wave plate each made of polypropylene resin are combined, An excellent broadband quarter wave plate can be obtained. In this specification, the value of Δn ₄₀₀ / Δn ₅₀₀ described above is defined as chromatic dispersion of phase difference. This is 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, it is affixed when a half-wave plate and a quarter-wave plate are bonded, or with a linear polarizing plate. Unevenness can be suppressed at the time of joining. 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.

  A raw film formed from such a polypropylene resin is stretched to develop a retardation. In this case, the thickness of the retardation film can be 25 μm or less. The film thickness is more 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 film thickness is preferably 5 μm or more, and more preferably 8 μm or more.

The refractive index of in-plane slow axis direction n _x of the film, the refractive index n _y in-plane fast axis direction (direction orthogonal with the slow axis and the plane), the refractive index in the thickness direction Nz and thickness, Where d is the in-plane retardation value (Ro), thickness direction retardation value (Rth), and Nz coefficient are defined by the following equations (I), (II), and (III), respectively. .

_{Ro = (n x -n y)} × d (I)
Rth = _{[(n x + n y) /} 2-Nz ] × d (II)
_{Nz = (n x -Nz) /} (n x -n y) (III)
From these equations (I), (II), and (III), the relationship between the Nz coefficient, the in-plane retardation value (Ro), and the thickness direction retardation value (Rth) is expressed by the following equation (IV ).

Nz = Rth / Ro + 0.5 (IV)
In the retardation film of the present invention, the in-plane retardation value (Ro) is more preferably in the range of 70 to 160 nm. The Nz coefficient is in the range of 0.9 to 1.6, and more preferably in the range of 0.95 to 1.05. An appropriate selection may be made in accordance with the characteristics required for the liquid crystal display device applied from these ranges. Here, if the Nz coefficient is approximately 1, In the above formula (III), meaning that n _y and Nz are approximately equal, such a phase difference film, becomes almost perfect uniaxial.

[Polypropylene resin]
The polypropylene resin constituting the retardation film of the present invention can be produced by a method of homopolymerizing propylene or a method of copolymerizing propylene and another copolymerizable comonomer using a known polymerization catalyst. it can. Examples of known polymerization catalysts include the following.

  (1) Ti-Mg based catalyst comprising a solid catalyst component containing magnesium, titanium and halogen as essential components; (2) A solid catalyst component comprising magnesium, titanium and halogen as essential components; A catalyst system in combination with a third component such as an electron donating compound, or (3) a metallocene catalyst.

  Among these catalyst systems, in the production of the polypropylene resin used for the retardation film of the present invention, a solid catalyst component containing magnesium, titanium and halogen as essential components combined with an organoaluminum compound and an electron donating compound. The most commonly used.

  More specifically, the organoaluminum compound is preferably triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, tetraethyldialumoxane, etc., and the electron donating compound is preferably cyclohexylethyldimethoxysilane. Tert-butylpropyldimethoxysilane, tert-butylethyldimethoxysilane, dicyclopentyldimethoxysilane and the like.

  On the other hand, examples of the solid catalyst component containing magnesium, titanium and halogen as essential components include the catalysts described in JP-A-61-218606, JP-A-61-287904, JP-A-7-216017, and the like. Examples of the metallocene catalyst include the catalyst systems described in Japanese Patent No. 2587251, Japanese Patent No. 2627669, Japanese Patent No. 2668732, and the like.

  Polypropylene resins include, for example, solution polymerization using an inert solvent typified by a hydrocarbon compound such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene, and xylene, and 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 used in the present invention can be composed of a propylene homopolymer, and contains a small amount of a comonomer mainly composed of propylene and copolymerizable therewith, for example, 20% by weight or less, preferably 10% by weight or less. Copolymerized with When a copolymer is used, the amount of comonomer is preferably 1% by weight or more.

  The comonomer copolymerized with propylene can be, for example, ethylene or an α-olefin having 4 to 20 carbon atoms. Specific examples of the α-olefin in this case include the following.

1-butene, 2-methyl-1-propene (above C ₄ ); 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene (above C ₅ ); 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-dimethyl-1-butene ( C ₆ ); 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl-1-butene (above C ₇₎ ); 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-pentene, 2-propyl-1-pente , 2,3-diethyl-1-butene (or C _8); 1-nonene (C _9); 1-decene (C _10); 1-undecene (C _11); 1-dodecene (C _12); 1- tridecene (C _13); 1-tetradecene (C _14); 1-pentadecene (C _15); 1-hexadecene (C _16); 1-heptadecene (C _17); 1-octadecene (C _18); 1-nonadecene ( C ₁₉ ).

  Preferred among the α-olefins are α-olefins having 4 to 12 carbon atoms, specifically 1-butene, 2-methyl-1-propene; 1-pentene, 2-methyl-1- Butene, 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-dimethyl-1-butene; 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl- 3-ethyl-1-butene; 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 And ten-, 2-propyl-1-pentene, 2,3-diethyl-1-butene; 1-nonene; 1-decene; 1-undecene; 1-dodecene, and the like. From the viewpoint of copolymerizability, 1-butene, 1-pentene, 1-hexene and 1-octene are preferable, and 1-butene and 1-hexene are more preferable.

  The copolymer may be a random copolymer or a block copolymer. Preferred copolymers include propylene / ethylene copolymers and propylene / 1-butene copolymers. In the propylene / ethylene copolymer and the propylene / 1-butene copolymer, the ethylene unit content and the 1-butene unit content are, for example, 616 of “Polymer Analysis Handbook” (published by Kinokuniya, 1995). Infrared (IR) spectrum measurement can be performed by the method described on the page.

  From the viewpoint of improving the transparency and workability of the retardation film, it is preferable to use propylene as a main component and a random copolymer with any unsaturated hydrocarbon. Of these, a copolymer with ethylene is preferred. When making a copolymer, it is advantageous that unsaturated hydrocarbons other than propylene have a copolymerization ratio of about 1 to 10% by weight, and a more preferable copolymerization ratio is 3 to 7% by weight. By setting the unit of unsaturated hydrocarbons other than propylene to 1% by weight or more, there is a tendency that an effect of improving processability and transparency appears. On the other hand, if the ratio exceeds 10% by weight, the melting point of the resin tends to decrease and the heat resistance tends to deteriorate, such being undesirable. In addition, when setting it as the copolymer of two or more types of comonomers, and a polypropylene, it is preferable that the total content of the unit derived from all the comonomers contained in the copolymer is the said range.

  The polypropylene resin used in the retardation film of 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, 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.

  This polypropylene resin may be blended with known additives 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. Antioxidants include, for example, 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.

[Polypropylene resin film]
Polypropylene resin can be formed into an original film by any method. This raw film is transparent and has substantially no in-plane retardation. For example, a polypropylene system having substantially no in-plane retardation by extrusion molding from molten resin, solvent casting method in which a resin dissolved in an organic solvent is cast on a flat plate, and the solvent is removed to form a film. A resin raw film can be obtained.

  As an example of a method for producing a raw film, a film forming method by extrusion will be described in detail. The 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, in the case of a single screw extruder, 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 in the resin supply unit, and the screw groove space volume in the resin metering unit The compression ratio, which is the ratio (the former / the latter), is about 1.5 to 4, and a screw such as a full flight type, a barrier type, and a type having a Maddock type kneading portion can be used. From the viewpoint of suppressing deterioration and decomposition of the polypropylene resin and uniformly melting and kneading, a barrier type screw having an L / D of 28 to 36 and a compression ratio of 2.5 to 3.5 is used. preferable. 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 nitrogen atmosphere or a vacuum. Furthermore, in order to remove the volatile gas generated by the deterioration or decomposition of the polypropylene resin, it is also preferable to provide an orifice of 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 tip of the extruder at the orifice means increasing the back pressure at the tip, 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 surface of the resin flow path, and its lip is plated or coated with a material having a low coefficient of friction with the molten polypropylene resin. Further, it is preferable to have a sharp edge shape in which the lip tip is polished to 0.3 mmφ or less. 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 eyes and simultaneously suppress the die line, so that a resin film having excellent appearance uniformity can be obtained. 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).
T-die lip width is less than 1500 mm: T-die thickness direction length> 180 mm (1)
T die has a lip width of 1500 mm or more: T die thickness direction length> 220 mm (2)
The lip width of the T die is less than 1500 mm: the length in the height direction of the T die> 250 mm (3)
The lip width of the T die is 1500 mm or more: the length of the T die in the height direction> 280 mm (4)
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 presses and rotates in the circumferential direction of the metal cooling roll. A desired 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, the molten sheet of polypropylene resin is directly sandwiched between the metal cooling roll and the touch roll for cooling. 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 sandwiched between the cooling roll and the touch roll as described above and cooled and solidified, both the cooling roll and the touch roll have their surface temperatures lowered, and the molten sheet is rapidly cooled. I need to do it. 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, if the surface temperature of the roll is lower than 0 ° C., condensation may form on the surface of the metallic cooling roll, and water droplets may adhere, resulting in a tendency to deteriorate the appearance of the 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 0.3S or less, more preferably 0.1S to 0.2S, expressed in the standard sequence of the maximum height. .

  The touch roll that forms the nip portion with the metal cooling roll has a surface hardness of 65 to 80 as a value measured by a spring type hardness test (A type) defined in JIS K 6301. Is more preferable, and 70 to 80 is more preferable. 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 a polypropylene resin film while maintaining a constant linear pressure without forming a bank.

  When a biaxially stretched film of a thermoplastic resin is sandwiched between a metallic cooling roll and a touch roll together with a molten sheet of polypropylene resin, the thermoplastic resin constituting the biaxially stretched film is strong with the polypropylene resin. Any resin may be used as long as it is not heat-sealed, and 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 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 when producing a polypropylene resin 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 becomes a film. Under the present circumstances, in order to protect the surface until it uses a film, you may wind up 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 of the present invention can be produced by laterally stretching a raw film made of a 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 preheating temperature near the melting point of the polypropylene resin;
(B) A stretching step of stretching the preheated film in the transverse direction at a stretching temperature lower than the preheating temperature; and (C) a heat setting step of heat-setting the film stretched in the transverse 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 equipped with a mechanism capable of independently adjusting the temperatures in a zone for performing a preheating step, a zone for performing a stretching step, and a zone for performing a 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 for 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 process of lateral stretching is a process 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 ambient 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 having excellent 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. By setting the draw ratio at this time to 3 times or more, the Nz coefficient 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 is a step of passing the film through a zone of a predetermined temperature 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 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.

[Optical characteristics when used as a wave plate]
When the retardation film of the present invention is used as a quarter-wave plate, the in-plane retardation value (Ro) is preferably in the range of 70 to 160 nm, and more preferably in the range of 80 to 150 nm. preferable. 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 On the other hand, when the retardation film of the present invention is used as a half-wave plate, the in-plane retardation value (Ro) is preferably in the range of 240 to 400 nm, and more preferably in the range of 260 to 330 nm. Is more preferable. The half-wave plate has a function of rotating the direction of linearly polarized light.

[Primer]
The polyolefin resin used as the raw material for the modified polyolefin resin is a propylene-α-olefin copolymer mainly composed of propylene and copolymerized with α-olefin, and can be selected from either a block copolymer or a random copolymer. it can. Examples of the α-olefin component include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene and the like. The propylene component content is optimally 50 to 90 mol%, and if it is 50 mol% or less, the adhesion of the retardation film to the skin layer is inferior, and if it is 90 mol% or more, flexibility is insufficient. Absent.

  Further, the modified amounts of the unsaturated polycarboxylic acid or derivative thereof and (meth) acrylic acid or derivative thereof in the modified polyolefin resin are preferably 0.1 to 20% by weight and 0.1 to 30% by weight, respectively. . If the amount of modification is less than this range, the solubility in a solvent is lowered, which is not preferable. Further, if the amount of modification is larger than this range, the adhesion to polyolefin is lowered, which is not preferable.

  Unsaturated polycarboxylic acids or derivatives thereof are unsaturated polycarboxylic acids such as maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, aconitic acid, phthalic acid, trimellitic acid, norbornene dicarboxylic acid Or these derivatives (For example, an acid anhydride, an acid halide, an amide, an imide, ester, etc.). Among these, it is preferable that 0.1 to 20% by weight of itaconic anhydride and maleic anhydride are contained from the viewpoint of adhesion force of the retardation film to the skin layer. These modified monomers can be used alone or in combination.

  (Meth) acrylic acid or derivatives thereof are (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, Examples include isobornyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, and acrylamide. These modified monomers can be used singly or in a plurality of types, but due to various coating properties of the resulting modified polyolefin resin, octyl (meth) acrylate of (meth) acrylic acid or its derivative is included in the modified polyolefin resin. It is preferable that at least one selected from lauryl (meth) acrylate, tridecyl (meth) acrylate, and stearyl (meth) acrylate is contained in an amount of 0.1 to 30% by weight. If the modification amount is less than this range, the solvent solubility of the modified polyolefin resin and the adhesion force of the retardation film to the skin layer are reduced. On the other hand, if the amount is too large, the highly reactive modified monomer forms an ultra-high molecular weight body, so that solvent solubility is deteriorated and the amount of homopolymer or copolymer that is not modified into a polyolefin skeleton is increased. Absent.

  Moreover, in the modified polyolefin resin used for this invention, monomers other than the said modified monomer may be used together in the range which does not impair the characteristic of this invention according to a use or the objective. Usable monomers are copolymerizable unsaturated monomers such as styrene, cyclohexyl vinyl ether and dicyclopentadiene. It is desirable that the amount of these monomers used does not exceed the total amount of the modified monomers grafted.

  A method for obtaining a modified polyolefin resin using the above-described modified monomer can be performed by a known method. Examples include a solution method in which a polyolefin resin is heated and dissolved in a solvent such as toluene and a modified monomer is added, and a melting method in which a modified monomer is added together with a polyolefin resin melted using a Banbury mixer, a kneader, an extruder, or the like. . The method for adding the modified monomer may be sequential addition or batch addition.

  Examples of the radical generator used in the reaction include benzoyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, dicumyl peroxide, tert-butyl peroxybenzoate, methyl ethyl ketone peroxide, and cumene hydroperoxide. Organic peroxides, and azonitriles such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile).

  In the modified polyolefin resin used for a primer, there is no restriction | limiting in particular in the molecular weight of polyolefin resin used as a starting material. However, the weight average molecular weight of the modified polyolefin resin is preferably 15,000 to 150,000, more preferably 30,000 to 120,000. Most preferably, it is 30,000-100,000. If it is less than 15,000, the adhesion force and cohesive force of the retardation film to the skin layer are inferior, and if it is more than 150,000, workability and solubility in a solvent decrease due to increased viscosity, which is not preferable.

  The primer used in the present invention is used by dissolving the above-described modified polyolefin resin in an organic solvent. Usable organic solvents include aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, nonane and decane, ester solvents such as ethyl acetate and butyl acetate, acetone, A ketone solvent such as methyl ethyl ketone and methyl butyl ketone, an alcohol solvent such as methanol, ethanol, propanol and butanol, or a mixed solvent thereof can be used. The solid content concentration of the modified polyolefin resin solution is preferably 10 to 50% by weight.

Moreover, it is preferable to mix alcohol with modified | denatured chlorinated polyolefin as an antifoamer of a primer liquid. Examples of the alcohol include ethanol, 1-propanol, 2-propanol, 1-butanol and the like.
Examples of resins that are commercially available as the modified polyolefin resin include “Aurolen 350T”, “Aurolen S-5106MX”, “Aurolen S-5189T” manufactured by Nippon Paper Industries, “Unistole P401”, “Mitsui Chemicals”. Unistor P801 "(both are trade names).

  Further, the method for applying the primer to the retardation film is not particularly limited. For example, spin coating, bar coating, roll coating, curtain coating, and die coating such as slot coating and extrusion coating. Etc. can be adopted. After the solution is applied, a solvent removal (drying) step by a method such as heating with a heater or blowing hot air is incorporated, and the solvent is removed by drying appropriately.

  Furthermore, when the primer layer 30 is applied to the retardation film 20 made of a polypropylene resin, it is preferable to perform a corona treatment. Thereby, the adhesiveness of the phase difference film 20 which consists of the primer layer 30 and polypropylene resin can be improved.

[Adhesive layer]
The pressure-sensitive adhesive layer 40 can be made of an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether, or the like as a base polymer. In particular, like acrylic adhesives, it has excellent optical transparency, retains appropriate wettability and cohesion, has excellent adhesion to substrates, and has weather resistance and heat resistance. However, it is preferable to select and use a material that does not cause peeling problems such as floating and peeling under the conditions of heating and humidification.

  The acrylic adhesive is composed of an alkyl ester of acrylic acid having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, or a butyl group, and (meth) acrylic acid or hydroxyethyl (meth) acrylate. An acrylic copolymer having a weight average molecular weight of 100,000 or more, which is blended with a functional group-containing acrylic monomer so that the glass transition temperature is preferably 25 ° C. or lower, more preferably 0 ° C. or lower, is used as the base polymer. Useful.

  The pressure-sensitive adhesive layer 40 can be formed by applying and drying a pressure-sensitive adhesive solution mainly composed of the base polymer as described above, and a pressure-sensitive adhesive layer is formed on the release treatment surface of the film subjected to the release treatment. It can also be formed by preparing a prepared film (film with a pressure-sensitive adhesive layer) and bonding it to the surface of the primer layer 30 on the pressure-sensitive adhesive layer side.

  Moreover, in this invention, a diffusion adhesive can also be used as an adhesive layer. The light diffusing agent used here may be fine particles having a refractive index different from that of the base polymer constituting the pressure-sensitive adhesive layer 40, and fine particles made of an inorganic compound or fine particles made of an organic compound (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 light diffusing agent incorporated therein has a refractive index of 1 What is necessary is just to select suitably from the thing of about ~ 2. The refractive index difference 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 set to 0.01 or more and 0.5 or less. Is preferred. 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). 1.550), 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). ) And silicone resin beads (refractive index 1.46).

  The blending amount of the light diffusing agent is appropriately determined in consideration of the haze value required for the light diffusing pressure-sensitive adhesive layer in which it is blended, the brightness of the image display device to which it is applied, Generally, the amount is about 3 to 30 parts by weight with respect to 100 parts by weight of the base polymer constituting the pressure-sensitive adhesive layer 40.

  In addition, the light diffusive pressure-sensitive adhesive layer containing the light diffusing agent ensures the brightness of the image display device to which the composite polarizing plate is applied, and from the viewpoint of making the display image less likely to bleed or blur. It is preferable that the haze is in the range of 20 to 80%. The haze is a value defined by JIS K 7105 and expressed by (diffuse transmittance / total light transmittance) × 100 (%).

  Although the thickness of an adhesive layer is determined according to the adhesive force etc., it is the range of 1-40 micrometers normally. In order to obtain a thin composite polarizing plate that is an object of the present invention, it is desirable to apply a thin coating within a range that does not impair properties such as workability and durability. Therefore, the thickness of the adhesive layer should be 3 to 25 μm to maintain good workability, show high durability, and maintain brightness when the image display device is viewed from the front or obliquely. From the viewpoint of preventing the display image from blurring or blurring, it is preferable.

[Elliptically polarizing plate]
The quarter-wave plate can be formed into an elliptical polarizing plate by laminating with a linear polarizing plate at a predetermined axial angle or by laminating with a linear polarizing plate at a predetermined axial angle together with a half-wave plate. . 2A and 2B are cross-sectional views illustrating a layer structure and a relationship between axial angles of one embodiment of the elliptically polarizing plate according to the present invention.

  With reference to FIG. 2 (A), in one form of this invention, the quarter wavelength plate 10 which consists of an above-mentioned polypropylene resin film can be laminated | stacked on the linearly-polarizing plate 50, and it can be set as the elliptically-polarizing plate 52. FIG. . In this case, referring to FIG. 2B, the angle to reach the in-plane slow axis 12 of the quarter-wave plate 10 with the counterclockwise direction being positive with respect to the absorption axis 22 of the linearly polarizing plate 50 as a reference. Arranging so that θ is 40 to 50 degrees, preferably about 45 degrees, functions almost as a circularly polarizing plate. Alternatively, the angle θ reaching the in-plane slow axis 12 of the quarter-wave plate 10 is 130 to 140 degrees, preferably approximately 135, with the counterclockwise direction being positive with respect to the absorption axis 22 of the linearly polarizing plate 50. Even if it arrange | positions so that it may become a degree, it will come to function as a substantially circularly-polarizing plate. Hereinafter, when expressing an angle, the counterclockwise rotation with respect to the reference axis is positive, as in the description here.

  Further, referring to FIG. 3A, in another embodiment of the present invention, a quarter-wave plate 10 and a half-wave plate 25 each made of the polypropylene resin film described above are laminated, and the The elliptical polarizing plate 55 can be formed by laminating the linear polarizing plate 50 on the half-wave plate 25 side. In this case, referring to FIG. 3B, the angle φ reaching the in-plane slow axis 17 of the half-wave plate 15 is 10 to 20 degrees, preferably based on the absorption axis 22 of the linearly polarizing plate 50. Is approximately 15 degrees, and the angle ψ from the in-plane slow axis 17 of the half-wave plate 25 to the in-plane slow axis 12 of the quarter-wave plate 10 is 55 to 65 degrees, preferably approximately 60 degrees. By arranging in this way, it almost functions 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 15 is 100 to 110 degrees, preferably about 105 degrees. Even if the angle ψ from the in-plane slow axis 17 to the in-plane slow axis 12 of the quarter-wave plate 10 is 55 to 65 degrees, preferably about 60 degrees, the circularly polarizing plate is still substantially circular. Will function as. The latter relationship (the angle from the absorption axis of the linearly polarizing plate to the in-plane slow axis of the half-wave plate 25 is 100 to 110 degrees) is represented by the reference numeral 22 in FIG. "Is equivalent to the state that is read as". " In the linear polarizing plate, the absorption axis and the transmission axis are in a relationship orthogonal to each other in the plane.

  In particular, as shown in FIG. 3A, a laminate of the quarter wavelength plate 10 and the half wavelength plate 25 functions as a quarter wavelength plate in a wide wavelength range in the visible light region, that is, in a wide band. Thus, the elliptically polarizing plate 55 in which the linearly polarizing plate 50 is laminated on the half-wave plate 25 side can convert linearly polarized light into circularly polarized light and circularly polarized light into linearly polarized light over a wide band. Furthermore, by comprising in this way, the angle dependence of the antireflection effect can also be reduced.

  The linearly polarizing plate 50 is an optical element having 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. Can be. 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. This polarizing 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.

  The transparent protective layer of the polarizing plate 50 may be composed of, for example, a film of an acetylcellulose-based resin typified by triacetylcellulose (TAC) or diacetylcellulose that has been conventionally used as a protective layer for a polarizing film. In addition, a film of a cyclic polyolefin resin typified 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.

  Moreover, as a 1/2 wavelength plate used above, the retardation film which consists of the said polypropylene-type resin may be used, and another conventionally well-known 1/2 wavelength plate may be used, and it is specifically limited. It is not a thing. Examples of other 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.

  In the production of the elliptically polarizing plate, the wave plate (retardation film) 10 and the polarizing plate 50 are bonded, and the wave plate (phase difference film) such as a quarter wavelength plate and a half wavelength is bonded to each other. For example, an adhesive layer can be used. As the pressure-sensitive adhesive layer, a layer mainly composed of an acrylic polymer having excellent transparency and durability is particularly preferably used. The thickness of the pressure-sensitive adhesive layer is usually in the range of 5 to 50 μm.

  In the elliptically polarizing plates 52 and 55 configured as described above, an adhesive layer is disposed on the surface side of the quarter-wave plate 10 so that they can be bonded to the liquid crystal cell. it can. This elliptically polarizing plate is laminated on at least one side of the liquid crystal cell to constitute a liquid crystal display device. The elliptically polarizing plate can be disposed on both sides of the liquid crystal cell, the elliptically polarizing plate can be disposed on one side of the liquid crystal cell, and another polarizing plate can be disposed on the other side. In pasting to a liquid crystal cell, it arrange | positions so that the 1/4 wavelength plate 10 side may face a liquid crystal cell.

[Liquid Crystal Display]
FIG. 4 is a schematic cross-sectional view showing an example of a liquid crystal display device in which the elliptically polarizing plate of the present invention is arranged on both surfaces of a liquid crystal cell. FIG. 4 shows an example in which the elliptically polarizing plate 52, which is a laminate of the quarter wavelength plate 10 and the linearly polarizing plate 50 shown in FIG. That is, in this example, an elliptically polarizing plate 52 composed of a quarter-wave plate 10 / a linearly polarizing plate 50 is disposed below the liquid crystal cell 60 via an adhesive layer, and the quarter-wave plate 10 side is disposed on the liquid crystal cell 60. The elliptical polarizing plate 52 composed of the quarter wavelength plate 10 / the linear polarizing plate 50 is disposed on the upper side of the liquid crystal cell 60 via the adhesive layer, and the quarter wavelength plate 10 side is liquid crystal. The layers are stacked so as to face the cell 60. Each elliptical polarizing plate 52 is disposed so that the absorption axis of the linear polarizing plate 50 is orthogonal. When this liquid crystal display device is used as a transmissive type or a transflective type, a backlight 70 is disposed on the outer side (lower side in the drawing) of one elliptical polarizing plate 52.

  FIG. 5 shows an example in which the elliptically polarizing plates 55 that are the laminates of the quarter-wave plate 10, the half-wave plate 25 and the linearly polarizing plate 50 shown in FIG. Is shown. That is, in this example, an elliptical polarizing plate 55 composed of a quarter wavelength plate 10/1/2 wavelength plate 25 / linear polarizing plate 50 is provided below the liquid crystal cell 60 via the adhesive layer 40. The four-wave plate 10 is laminated so as to face the liquid crystal cell 60, and from the quarter-wave plate 10/1/2 wave plate 25 / linearly polarizing plate 50 on the upper side of the liquid crystal cell 60 via the adhesive layer 40. An elliptically polarizing plate 55 is laminated so that the quarter-wave plate 10 faces the liquid crystal cell 60. Each elliptically polarizing plate 55 is disposed so that the absorption axes of the linearly polarizing plates 50 are orthogonal to each other. When this liquid crystal display device is used as a transmissive type or a transflective type, a backlight 70 is disposed outside (on the lower side in the drawing) of one elliptical polarizing plate.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples,% representing the content is based on weight unless otherwise specified.

[Retardation film made of polypropylene resin]
A propylene / ethylene random copolymer containing about 5% ethylene unit (“Sumitomo Nobrene W151” manufactured by Sumitomo Chemical Co., Ltd.) was formed into a film having a thickness of 40 μm. The film was subjected to transverse uniaxial stretching to obtain a uniaxial retardation film. This retardation film has Ro = 90 nm, Rth = 45 nm, and a thickness of 9 μm. In addition, on one side of the retardation film made of polypropylene, a trade name “Tretec 7332” manufactured by Toray Film Processing Co., Ltd. was bonded as a protective film.

[Primer 1]
As a primer, 45 parts of toluene and 1 part by weight of 2-propanol were added to 100 parts by weight of a trade name “Auroren S-5189T” manufactured by Nippon Paper Chemicals Co., Ltd., which is a maleic anhydride / acrylic modified olefin. It was set as the composition for coating.

The molecular weight of Auroren S-5189T is 60000-80000.
Example 1
(A) Lamination | stacking of retardation film and primer The corona discharge process was performed by the integrated irradiation amount of 15.9 kJ / m < ² > on the opposite side to the side by which the surface protection film of the retardation film which consists of polypropylene resin is laminated | stacked. Within 5 minutes after the corona discharge treatment, the primer 1 coating composition was applied to the corona-treated surface using a Mayer bar (# 6) and dried in an oven at 80 ° C. for 3 minutes. An 8 μm primer layer was formed on the retardation film.
(B) Production of an elliptically polarizing plate On the other side of a polarizing plate [SR062 manufactured by Sumitomo Chemical Co., Ltd.] obtained by adhering a saponified triacetylcellulose protective film to one of the retardation films made of polypropylene resin, The adhesive surface of the composite polarizing plate having a pressure-sensitive adhesive surface coated with a urethane acrylate-based pressure-sensitive adhesive layer [NS300MP sold by Lintec Co., Ltd.] and the protective film for the retardation film prepared in (a) above The surface is peeled off and subjected to a corona discharge treatment at an integrated dose of 15.9 kJ / m ^2. Within 5 minutes after the corona discharge treatment, the corona treatment surface is produced from the adhesive surface of the composite polarizing plate and the above (a). The phase difference film was bonded to the surface opposite to the surface where the primer layer was formed. Thereafter, the primer side was also subjected to a corona discharge treatment at an integrated dose of 15.9 kJ / m ² . Within 5 minutes after this corona discharge treatment, an acrylic pressure-sensitive adhesive [P3132 sold by Lintec Co., Ltd.] was bonded to the corona-treated surface to obtain an elliptical polarizing plate with a pressure-sensitive adhesive layer.
(C) Thickness measurement of elliptically polarizing plate The thickness of the composite polarizing plate with the pressure-sensitive adhesive layer obtained in (b) was measured using a digital length measuring device “MH-15M” manufactured by Nikon Corporation. The results are shown in Table 1.
(D) Throwing force test The protective film of the retardation film with a primer layer obtained in (a) was peeled off, and the surface was subjected to corona discharge treatment under the condition of an integrated irradiation amount of 15.9 kJ / m ² . Further, a biaxial thermoplastic saturated norbornene resin [ZB0555124 manufactured by Nippon Zeon Co., Ltd.] was subjected to corona discharge treatment under the condition of an integrated irradiation amount of 15.9 kJ / m ² . Within 10 minutes after the corona discharge treatment, the active energy ray-curable resin composition containing the epoxy compound was applied to the corona-treated surface of the biaxial thermoplastic saturated norbornene resin using the Meyer bar (# 1). The coated surface and the corona-treated surface of the retardation film with a primer layer were bonded together, and UV-cured at 500 mW / 1500 mJ with a UV irradiation device manufactured by FUSION. Next, the surface of the primer layer was subjected to a corona discharge treatment at an integrated dose of 15.9 kJ / m ² , and within 5 minutes after the corona discharge treatment, an acrylic adhesive (from Lintec Corporation) was applied to the corona treatment surface. P3132) sold on the market was laminated to produce a retardation film with an adhesive, and an adhesive evaluation film was produced. Thereafter, it was left for 1 day in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH. This adhesive evaluation film was cut into a width of 25 mm and a length of about 200 mm, and the adhesion strength at three points in the length direction was evaluated using the above-mentioned “adhesion strength evaluation device” manufactured by Japan System Group Co., Ltd. Evaluation was made by using a styrene rubber having a hardness of 60 degrees and the length of the pressure-sensitive adhesive layer peeled off from the coating retardation layer when slid 20 times from a certain direction while pressing with a pressing force of 0.4 MPa. The three-point average was determined as the peel distance. The measurement was carried out in an atmosphere having a temperature of 23 ° C. and a humidity of 60% RH. The results are shown in Table 1.
(E) Glass plate adhesion peeling test The film for adhesion evaluation obtained in (d) was cut into a width of 25 mm and a length of about 200 mm, and the pressure-sensitive adhesive layer surface was bonded to soda glass, and then an autoclave. A pressure treatment was performed at a pressure of 5 kgf / cm ² and a temperature of 50 ° C. for 20 minutes, and the mixture was left for 1 day in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH. Peeling is performed at 90 ° at a crosshead speed (peeling speed) of 200 mm / min in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH using a universal tensile tester (AG-1, manufactured by SHIMAZU Co., Ltd.). Evaluation was made by a peel test. The measurement was carried out in an atmosphere having a temperature of 23 ° C. and a humidity of 60% RH.

In Table 1, the peelability symbols are shown below.
○: The adhesive layer could be peeled off without remaining on the glass plate.

X: The pressure-sensitive adhesive layer remained on the glass plate and peeled off.
[Primer 2]
As a primer, 30 parts of toluene and 10 parts of 2-propanol as an antifoaming agent are used for 40 parts by weight of a trade name “Aurolen 250-MX” manufactured by Nippon Paper Chemicals Co., Ltd. which is maleic anhydride / acrylic modified olefin. Partly added to form a coating composition. The molecular weight of Auroren 250-MX is 60000-80000.

Example 2
(A) Lamination | stacking of retardation film and primer The corona discharge process was performed by the integrated irradiation amount of 15.9 kJ / m < ² > on the opposite side to the side by which the surface protection film of the retardation film which consists of polypropylene resin was laminated | stacked. Within 5 minutes after the corona discharge treatment, the primer 2 coating composition was applied to the corona-treated surface using a Mayer bar (# 14) and dried in an oven at 80 ° C. for 5 minutes. A 0 μm primer layer was formed on the retardation film.
(B) Production of elliptically polarizing plate An elliptically polarizing plate was produced in the same manner as in Example 1.
(C) Thickness measurement of elliptically polarizing plate It measured like Example 1. FIG. The measurement results are shown in Table 1.
(D) Throwing force test It measured like Example 1. FIG. The measurement results are shown in Table 1.
(E) Glass plate adhesion peeling test The measurement was performed in the same manner as in Example 1. The measurement results are shown in Table 1.

[Primer 3]
As a primer, 3 parts by weight of 2-propanol was added as a defoaming agent to 100 parts by weight of the product name “Aurolen 350T” manufactured by Nippon Paper Chemicals Co., Ltd., a maleic anhydride / acrylic modified olefin. A composition was obtained. The molecular weight of Aurolen 350T is 60000-80000.

Example 3
(A) Lamination | stacking of retardation film and primer The corona discharge process was performed by the integrated irradiation amount of 15.9 kJ / m < ² > on the opposite side to the side by which the surface protection film of the retardation film which consists of polypropylene resin was laminated | stacked. Within 5 minutes after the corona discharge treatment, the primer 3 coating composition was applied to the corona-treated surface using a Mayer bar (# 3) and dried in an oven at 80 ° C. for 3 minutes. An 8 μm primer layer was formed on the retardation film.
(B) Production of elliptically polarizing plate An elliptically polarizing plate was produced in the same manner as in Example 1.
(C) Thickness measurement of elliptically polarizing plate It measured like Example 1. FIG. The measurement results are shown in Table 1.
(D) Throwing force test It measured like Example 1. FIG. The measurement results are shown in Table 1.
(E) Glass plate adhesion peeling test The measurement was performed in the same manner as in Example 1. The measurement results are shown in Table 1.

[Primer 4]
As a primer, 3 parts by weight of 2-propanol as an antifoaming agent is added to 100 parts by weight of a trade name “Auroren S-5106-MX” manufactured by Nippon Paper Chemicals Co., Ltd., which is a maleic anhydride / acrylic modified olefin. Thus, a coating composition was obtained. The molecular weight of Auroren S-5106-MX is 60000-80000.

Example 4
(A) Lamination | stacking of retardation film and primer The corona discharge process was performed by the integrated irradiation amount of 15.9 kJ / m < ² > on the opposite side to the side by which the surface protection film of the retardation film which consists of polypropylene resin is laminated | stacked. Within 5 minutes after the corona discharge treatment, the primer 4 coating composition was applied to the corona-treated surface using a Mayer bar (# 3) and dried in an oven at 80 ° C. for 3 minutes. An 8 μm primer layer was formed on the retardation film.
(B) Production of elliptically polarizing plate An elliptically polarizing plate was produced in the same manner as in Example 1.
(C) Thickness measurement of elliptically polarizing plate It measured like Example 1. FIG. The measurement results are shown in Table 1.
(D) Throwing force test It measured like Example 1. FIG. The measurement results are shown in Table 1.
(E) Glass plate adhesion peeling test The measurement was performed in the same manner as in Example 1. The measurement results are shown in Table 1.

Comparative Example 1
(A) Preparation of retardation film without primer layer A surface of the retardation film made of polypropylene was subjected to corona discharge treatment with an integrated irradiation amount of 15.9 kJ / m ² . Within 5 minutes after the corona discharge treatment, an acrylic pressure-sensitive adhesive [P3132 sold by Lintec Corporation] was bonded to the corona-treated surface.
(B) Production of elliptically polarizing plate An elliptically polarizing plate was produced in the same manner as in Example 1.
(C) Measurement of thickness of elliptically polarizing plate In the same manner as in Example 1, the thickness of the elliptically polarizing plate was measured. The results are shown in Table 1.
(E) Throwing force test Throwing force was evaluated in the same manner as in Example 1. The results are shown in Table 1.
(F) Glass plate sticking peel test The peelability was evaluated in the same manner as in Example 1.

It is a section schematic diagram showing the phase contrast film with an adhesive layer of the present invention. (A) is the cross-sectional schematic of one form of the elliptically polarizing plate of this invention, (B) is the schematic for demonstrating the axial angle of a polarizing plate. (A) is the cross-sectional schematic of one form of the elliptically polarizing plate of this invention, (B) is the schematic for demonstrating the axial angle of a polarizing plate. It is the cross-sectional schematic which shows the liquid crystal display device of this invention. It is the cross-sectional schematic which shows the liquid crystal display device of this invention.

Explanation of symbols

  10 retardation film with adhesive layer, 20 retardation film, 30 primer, 40 adhesive layer, 50 polarizing plate.

Claims (6)

  A retardation film made of a polypropylene resin, a primer layer, and an adhesive layer are formed in this order, and the primer layer is modified with unsaturated polycarboxylic acid or a derivative thereof, and (meth) acrylic acid or a derivative thereof, and A retardation film with a pressure-sensitive adhesive layer, which is a modified polyolefin resin having a weight average molecular weight of 15,000 to 150,000.   The retardation film with an adhesive layer according to claim 1, wherein the retardation film made of a polypropylene resin is made of a copolymer of propylene and ethylene containing 10% by weight or less of ethylene units.   The retardation film with a pressure-sensitive adhesive layer according to claim 1 or 2, wherein the retardation film is a quarter-wave plate.   An elliptically polarizing plate in which the retardation film with a pressure-sensitive adhesive layer according to claim 1 is laminated on a polarizing plate.   The elliptically polarizing plate according to claim 4, further comprising a half-wave plate between the retardation film and the polarizing plate.   6. A liquid crystal display device, wherein the elliptically polarizing plate according to claim 4 or 5 is laminated on at least one side of a liquid crystal cell.

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