KR20100138994A

KR20100138994A - Retardation film with pressure-sensitive adhesive layer and elliptical polarizer and liquid-crystal display both employing the same

Info

Publication number: KR20100138994A
Application number: KR1020107022109A
Authority: KR
Inventors: 에쯔오 구메; 도시까즈 마쯔모또
Original assignee: 스미또모 가가꾸 가부시키가이샤
Priority date: 2008-03-05
Filing date: 2009-03-02
Publication date: 2010-12-31
Also published as: WO2009110425A1; TW201003249A; TWI490609B; JP2009210878A; JP5120938B2; CN101960339A

Abstract

The present invention provides a retardation film having a pressure-sensitive adhesive layer having improved adhesion between the retardation film 20 containing the polypropylene resin and the pressure-sensitive adhesive layer 40. The retardation film 20, the primer layer 30, and the adhesive layer 40 which consist of polypropylene resin are formed in this order, and the said primer layer 30 is unsaturated polycarboxylic acid or unsaturated polycarboxylic acid. It provides a phase difference film with a pressure-sensitive adhesive layer, comprising a modified polyolefin resin having a weight average molecular weight of 15,000 to 150,000, and a derivative of (meth) acrylic acid or a derivative of (meth) acrylic acid. The retardation film 20 is composed of a copolymer of propylene and ethylene containing 10 wt% or less of ethylene units, and the retardation film 20 of the retardation film with the pressure-sensitive adhesive layer is a quarter wave plate. desirable.

Description

Retardation film with an adhesive layer, and an elliptical polarizer and a liquid crystal display device using the same {RETARDATION FILM WITH PRESSURE-SENSITIVE ADHESIVE LAYER AND ELLIPTICAL POLARIZER AND LIQUID-CRYSTAL DISPLAY BOTH EMPLOYING THE SAME}

The present invention relates to a retardation film containing a polypropylene resin, an elliptically polarizing plate using the retardation film, and in particular, a retardation film having a pressure-sensitive adhesive layer laminated with a specific primer layer on a retardation film containing a polypropylene resin and the same. It is related with the used elliptically polarizing plate and liquid crystal display device.

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

As one of the methods of viewing angle enlargement, what uses the retardation film according to the mode of a liquid crystal is mentioned. Examples of the retardation film include a birefringent film containing a stretched film of various plastics, a film having a liquid crystal layer in which discotic liquid crystals or nematic liquid crystals are aligned, a liquid crystal layer formed on the film substrate, and the like. Can be.

Specific examples of the plastic forming the birefringent film include polycarbonate, polystyrene, polymethyl methacrylate, polyolefin, polyamide, and the like.

As the retardation film of the polyolefin resin, an amorphous cyclic polyolefin resin, also called an alicyclic polyolefin or norbornene resin, has excellent heat resistance and moisture resistance, excellent transparency, and relatively simple adjustment of the retardation value. It is widely used for such reasons.

For example, Japanese Patent Laid-Open No. 11-149015 (Patent Document 1) discloses an example in which a lambda / 2 stretched film or a lambda / 4 stretched film is produced from a cyclic polyolefin film. In addition, JP 2007-286615 A (Patent Document 2) discloses applying a polypropylene resin to a retardation film. However, since non-polar polyolefin resins often have insufficient adhesive strength with the pressure-sensitive adhesive layer, improvement is required.

On the other hand, Japanese Patent Application Laid-Open No. 2004-277617 (Patent Document 3) discloses a polyolefin resin modified with a derivative of unsaturated polycarboxylic acid or unsaturated polycarboxylic acid and a derivative of (meth) acrylic acid or (meth) acrylic acid. It is described to apply to a binder composition for the purpose of protection or plastering, such as polypropylene resin.

Japanese Patent Laid-Open No. 11-149015 Japanese Patent Laid-Open No. 2007-286615 Japanese Patent Laid-Open No. 2004-277617

Since the retardation film which consists of polypropylene resins is inferior to adhesiveness with an adhesive layer compared with cyclic polyolefin resin, when peeling the optical member which bonded optical films, such as a polarizing plate and retardation film, from a liquid crystal cell, an adhesive There was a problem that some of the layers remained. In this invention, in order to solve such a problem, it aims at providing the retardation film with an adhesive layer which improved the adhesiveness of the retardation film which consists of polypropylene resins, and an adhesive layer. In addition, another object of the present invention is to provide an elliptical polarizing plate using the phase difference film with the pressure-sensitive adhesive layer. Another object of the present invention is to provide a liquid crystal display using the elliptical polarizing plate.

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

It is preferable that the retardation film containing the said polypropylene resin consists of a copolymer of propylene and ethylene containing 10 weight% or less of ethylene units. Moreover, it is preferable that the said retardation film of the retardation film with an adhesive layer is a quarter wave plate.

The present invention relates to an elliptically polarizing plate comprising a polarizing plate and a phase difference film with the pressure-sensitive adhesive layer laminated on the polarizing plate. The elliptical polarizing plate may include a half wave plate between the retardation film with the pressure-sensitive adhesive and the elliptical polarizing plate. Another aspect of the present invention is a liquid crystal display device in which the elliptical polarizing plate is laminated on at least one side of a liquid crystal cell.

Since the adhesiveness of the retardation film containing polypropylene resin and an adhesive layer is low, the composite polarizing plate using the retardation film containing polypropylene resin is bonded to the glass substrate of a liquid crystal cell, and when it bonds again, Although a part may remain in a glass substrate, the elliptical polarizing plate using the retardation film with the adhesive layer in which the retardation film containing the polypropylene resin, primer resin, and an adhesive layer in this order were formed in this order is polypropylene. Since the adhesiveness of the phase difference film containing resin and an adhesive layer improves, it has an effect that a part of adhesive layer does not remain on a glass substrate.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional schematic drawing which shows the retardation film with an adhesive layer of this invention.
FIG. 2: (A) is sectional schematic of one form of the elliptically polarizing plate of this invention, (B) is schematic for demonstrating the axial angle of a polarizing plate. FIG.
(A) is a cross-sectional schematic of one form of the elliptical polarizing plate of this invention, (B) is a schematic for demonstrating the axial angle of a polarizing plate.
4 is a schematic cross-sectional view showing a liquid crystal display of the present invention.
5 is a schematic cross-sectional view showing a liquid crystal display device of the present invention.
<Description of the code>
10: retardation film with adhesive layer
12, 17: in-plane slow axis
20: retardation film
22: absorption shaft
25: 1/2 wave plate
30: primer layer
40: adhesive layer
50: polarizer
52: elliptical polarizer

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a schematic cross-sectional view of a retardation film with an adhesive layer according to the present invention. As for the retardation film 10 with an adhesive layer of this invention, the primer layer 30 and the adhesive layer 40 are formed in this order in one side of the retardation film 20 containing polypropylene resin. And the polarizing plate is bonded by the retardation film on the opposite side to the adhesive layer 40.

[Retardation Film]

In this invention, resin containing polypropylene resin is extended | stretched normally, and it is set as retardation film. Since the retardation film containing polypropylene resin is crystalline, the expression rate of retardation value is very high and a large retardation value can be obtained simply by extending | stretching. For this reason, the retardation film which has a desired retardation value by thin film thickness can be obtained.

Further, the polypropylene resin has a difference (birefringence) Δn ₄₀₀ between an in-plane maximum refractive index and a minimum refractive index at a wavelength of 400 nm, and a difference (birefringence) Δn between an in-plane maximum refractive index and a minimum refractive index at a wavelength of 500 nm. _Since the ratio (Δn ₄₀₀ / Δn ₅₀₀ ) to ₅₀₀ is less than 1.05, when the 1/2 wave plate and the 1/4 wave plate each made of polypropylene resin are combined, the excellent broadband 1/4 wave plate You can do In the present specification, the value of Δn ₄₀₀ / Δn ₅₀₀ is defined as the wavelength dispersion of the phase difference. The wavelength dispersion of this phase difference is also called simply "wavelength dispersion."

In addition, since the polypropylene-based resin has a small photoelastic modulus of about 2 x 10 ^-13 cm 2 / dyne, the bonding unevenness at the time of bonding of the 1/2 wave plate and the 1/4 wave plate or the bonding of the linear polarizing plate It can be suppressed. In addition, gray hair can also be suppressed in the heat resistance test. Moreover, since a polypropylene resin can be extended | stretched with high magnification, it is possible to produce a fully uniaxial retardation film by lateral stretching, and can achieve thin film and wide width simultaneously, and is excellent in utilization efficiency.

Retardation is expressed by extending | stretching the raw film formed into a film from such polypropylene resin. In this case, the film thickness of retardation film can be 25 micrometers or less. As for the film thickness, it is more preferable that it is 20 micrometers or less. When the film thickness of retardation film exceeds 25 micrometers, the advantage of thin film becomes difficult to be exhibited effectively. Moreover, when the film thickness is too small, wrinkles etc. are easy to generate | occur | produce in retardation film, and there exists a tendency for deterioration of the handleability at the time of winding-up or bonding. Therefore, it is preferable that the film thickness is 5 micrometers or more, and it is more preferable that it is 8 micrometers or more.

When the refractive index in the in-plane slow axis direction of the retardation film is n _x , the refractive index in the in-plane fast axis direction (direction perpendicular to the ground axis and in-plane orthogonal) is n _y , the refractive index in the thickness direction is N _z , and the thickness is d, The phase difference value Ro in the phase, the phase difference value Rth in the thickness direction, and the Nz coefficient are defined by the following formulas I, II, and III, respectively.

In addition, from these formulas (I), (II) and (III), the relationship between the Nz coefficient, the in-plane phase difference value Ro, and the phase difference value Rth in the thickness direction can be expressed by the following equation IV.

In the present invention, the in-plane retardation value Ro of the retardation film is more preferably in the range of 70 to 160 nm. In addition, the Nz coefficient is in the range of 0.9 to 1.6, more preferably in the range of 0.95 to 1.05. In-plane retardation value Ro and Nz coefficient of a retardation film can be suitably selected in the range mentioned above according to the characteristic calculated | required by the liquid crystal display device to which a retardation film is applied. Here, if the Nz coefficient is almost 1, it means that n _y and Nz are almost equal in the above formula (III), and this retardation film is almost completely uniaxial.

[Polypropylene Resin]

In this invention, the polypropylene resin which comprises retardation film can be manufactured by the method of homopolymerizing propylene using a well-known polymerization catalyst, or the method of copolymerizing propylene and another copolymerizable comonomer. As a well-known polymerization catalyst, the following are mentioned, for example.

(1) a Ti-Mg-based catalyst comprising a solid catalyst component containing magnesium, titanium, and halogen as essential components; and (2) an organoaluminum compound in the solid catalyst component containing magnesium, titanium, and halogen as essential components. It is a catalyst system which combined 3rd components, such as an electron donating compound, or (3) metallocene type catalyst.

Among these catalyst systems, in the production of polypropylene resins used in retardation films, the combination of an organoaluminum compound and an electron donating compound in a solid catalyst component containing magnesium, titanium and halogen as essential components can be most commonly used.

More specifically, examples of the organoaluminum compound include triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, tetraethyldialumoxane, and the like. Preferably, cyclohexyl ethyl dimethoxy silane, tert- butylpropyl dimethoxy silane, tert- butyl ethyl dimethoxy silane, dicyclopentyl dimethoxy silane, etc. are mentioned.

In addition, as a solid catalyst component which has magnesium, titanium, and a halogen as an essential component, For example, Unexamined-Japanese-Patent No. 61-218606, Unexamined-Japanese-Patent No. 61-287904, Japanese Patent Laid-Open ) And the catalyst system described in Japanese Patent Application Laid-Open No. 7-216017. The catalyst system described in, for example, Japanese Patent No. 2587251, Japanese Patent No. 2627669, Japanese Patent No. 2668732, and the like. Can be.

The polypropylene resin is, for example, a solution polymerization method using an inert solvent represented by a hydrocarbon compound such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, or a liquid monomer as a solvent. It can manufacture by the bulk polymerization method to be used, the gas phase polymerization method which superposes | polymerizes the monomer of a gas as it is. The polymerization by these methods may be carried out either batchwise or continuously.

The stereoregularity of the polypropylene resin may be any one 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 not only be composed of a propylene homopolymer, but also a small amount, for example, 20 wt% or less, preferably 10 wt% of a comonomer mainly composed of propylene and copolymerizable therewith. It may be copolymerized at the following ratio. In the case of a copolymer, the amount of the comonomer is preferably 1% by weight or more.

The comonomer copolymerized with propylene may be, for example, ethylene or an α-olefin having 4 to 20 carbon atoms. As an alpha olefin in this case, the following are specifically ,.

That is, 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 (above 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-pentene, 2,3-diethyl-1-butene (more than 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 ) and the like.

Among the α-olefins, preferred are α-olefins having 4 to 12 carbon atoms, specifically 1-butene and 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-pentene, 2-propyl-1-pentene, 2,3-diethyl-1-butene; 1-nonene; 1-decene; 1-undecene; 1-dodecene, etc. are mentioned. 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 or the propylene / 1-butene copolymer, the content of the ethylene unit or the content of the 1-butene unit is described, for example, in the "Polymer Analysis Handbook" (1995, published by Kinokuniya Bookstore). It can obtain | require by the method of performing infrared (IR) spectrum measurement described on the page.

From a viewpoint of improving transparency and workability as a retardation film, it is preferable to set it as the random copolymer with arbitrary unsaturated hydrocarbons mainly using propylene, and the random copolymer with ethylene is especially preferable. In the case of using a copolymer, unsaturated hydrocarbons other than propylene are advantageously about 1 to 10% by weight of the copolymer, and more preferably 3 to 7% by weight of the copolymer. When the unit of unsaturated hydrocarbons other than propylene is 1 weight% or more, there exists a tendency which the effect of improving workability and transparency arises. On the other hand, when it exceeds 10 weight% of a copolymer, melting | fusing point of resin will become low and there exists a tendency for heat resistance to deteriorate. In addition, when making into a copolymer of 2 or more types of comonomers and polypropylene, it is preferable that the sum total content of the unit derived from all the comonomers contained in the copolymer is the said range.

Melt flow rate (MFR) of the polypropylene resin used for retardation film measured by temperature 230 degreeC and load 21.18 N based on JISK7110 in this invention is 0.1-200 g / 10min, especially 0.5-50 g / It is preferable to be in the range of 10 minutes. By using the polypropylene resin in which MFR exists in this range, a uniform film-like thing can be obtained without putting a large load on an extruder.

A known additive may be blended with this polypropylene resin in a range that does not impair the effects of the present invention. As an additive, antioxidant, a ultraviolet absorber, an antistatic agent, a lubricating agent, a nucleating agent, an antifog additive, an anti blocking agent, etc. are mentioned, for example. Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, hindered amine light stabilizers, and the like. In one molecule, for example, a phenolic antioxidant mechanism and A complex antioxidant having a unit having a phosphorus antioxidant can also be used. As a ultraviolet absorber, a ultraviolet absorber like 2-hydroxy benzophenone series and a hydroxyphenyl benzotriazole system, a benzoate system sunscreen etc. are mentioned, for example. The antistatic agent may be any of polymer type, oligomer type, and monomer type. Lubricants 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-based nucleating agents, organic phosphate-based nucleating agents, and polymer-type nucleating agents such as polyvinylcycloalkane. As an antiblocking agent, as long as it is a spherical particle | grains or a shape close to it, it can use regardless of an inorganic type and an organic type. These additives can also use multiple types together.

[Plastic film of polypropylene resin]

Polypropylene resin can be formed into a film by arbitrary methods, and can be made into a raw film. This disc film is transparent and substantially free of in-plane retardation. For example, the raw film of polypropylene resin which is substantially free of in-plane retardation by the extrusion molding method from molten resin, the solvent casting method which casts the resin melt | dissolved in the organic solvent on a flat plate, removes a solvent, and forms into a film. You can get it.

As an example of the method of manufacturing a raw film, the film forming method by extrusion molding is explained in full detail. Polypropylene resin is melt-kneaded by the rotation of a screw in an extruder, and is extruded from a T die into a sheet form. The temperature of the molten phase sheet extruded is about 180-300 degreeC normally. At this time, when the temperature of a molten phase sheet is less than 180 degreeC, stretchability is inadequate, the thickness of the obtained raw film may become nonuniform, and it may become a raw film with retardation nonuniformity. Moreover, when the temperature exceeds 300 degreeC, deterioration and decomposition | disassembly of resin are easy to generate | occur | produce, foam may generate | occur | produce in a sheet | seat, or a carbide may be included.

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 a ratio of the length L of the screw to the diameter D, is about 24 to 36, and the space volume of the screw groove in the resin supply part and the space volume of the screw groove in the resin metering part. Compression ratios of the ratio (the former / the latter) are about 1.5 to 4, and a screw such as a full flight type, a barrier type, or a type having a kneading portion of syphilis type can be used. It is preferable to use the barrier type screw whose L / D is 28-36 and a compression ratio is 2.5-3.5 from a viewpoint of suppressing deterioration and decomposition of a polypropylene resin, and melt-kneading uniformly. Moreover, in order to suppress deterioration and decomposition | disassembly of a polypropylene resin as much as possible, it is preferable to set it as nitrogen atmosphere or a vacuum in an extruder. Moreover, in order to remove the volatile gas which arises when a polypropylene resin deteriorates or decomposes, it is also preferable to provide the orifice of 1 mm (phi) or more and 5 mm (phi) or less in the tip of an extruder, and to raise the resin pressure of an extruder tip part. Increasing the resin pressure at the tip of the extruder by the orifice means increasing the back pressure at the tip, whereby the stability of the extrusion can be improved. The diameter of the orifice to be used is more preferably 2 mmφ or more and 4 mmφ or less.

It is preferable that the T die used for extrusion is free of minute steps and scratches on the surface of the flow path of the resin, and its lip portion is plated or coated with a material having a small coefficient of friction with the molten polypropylene resin. It is preferable that the edge shape is a sharp edge polished to 0.3 mmφ or less. Examples of the material having a small coefficient of friction include tungsten carbide and fluorine-based special platings. By using such a T die, generation | occurrence | production of a lump can be suppressed and a die line can be suppressed at the same time, and the disk film excellent in the uniformity of an external appearance is obtained. As for this T die, a manifold has a coat hanger shape, it is preferable to satisfy the following conditions (1) or (2), and it is more preferable to satisfy conditions (3) or (4).

The lip width of the T die is less than 1500 mm: the thickness direction length of the T die> 180 mm... (One)

Lip width of T die is 1500 mm or more: T die thickness direction length> 220 mm... (2)

Lip width of the T die is less than 1500 mm: length in the height direction of the T die> 250 mm... (3)

Lip width of the T die is 1500 mm or more: length in the height direction of the T die> 280 mm... (4)

By using a T die that satisfies these conditions, the flow of molten polypropylene-based resin in the T die can be summarized, and the lip portion can be extruded while suppressing thickness unevenness, so that the thickness precision is excellent. The more uniform raw film of retardation can be obtained.

From a viewpoint of suppressing the extrusion fluctuation of a polypropylene resin, it is preferable to attach a gear pump through an adapter between an extruder and a T die. Moreover, in order to remove the foreign material in a polypropylene resin, it is preferable to attach a leaf disc filter.

Pressing the molten-phase sheet extruded from a T die between a metal cooling roll (also called a chill roll or a casting roll) and a touch roll including an elastic body which rotates in contact with the circumferential direction of the metal cooling roll is pressed. By cooling and solidifying, a desired raw film can be obtained. Under the present circumstances, an elastic body, such as rubber | gum, may be a surface as it is, and the touch roll may coat | cover the surface of an elastic body roll with the outer cylinder which consists of a metal sleeve. When using the touch roll coated with the outer cylinder which the surface of an elastic body roll consists of a metal sleeve, the molten-phase sheet of polypropylene resin is directly inserted and cooled between a metal cooling roll and a touch roll. On the other hand, when using the touch roll whose surface is an elastic body, it can also be pinched through the biaxially stretched film of a thermoplastic resin between the molten-phase sheet of polypropylene resin, and a touch roll.

In the case where the molten-phase sheet of polypropylene-based resin is sandwiched between the cooling rolls and the touch rolls as described above, the cooling rolls and the touch rolls need to lower their surface temperature and quench the molten-phase sheet. For example, it is preferable that the surface temperature of a cooling roll and a touch roll is adjusted to the range of 0 degreeC or more and 30 degrees C or less. When these surface temperatures exceed 30 degreeC, since cooling solidification of a molten phase sheet takes time, the crystal component in a polypropylene resin grows, and the raw film obtained may be inferior to transparency. Surface temperature of a cooling roll and a touch roll becomes like this. Preferably it is 30 degrees C or less, More preferably, it is less than 25 degreeC. On the other hand, when the surface temperature of a cooling roll and a touch roll is less than 0 degreeC, water droplets may adhere to the surface of a metal cooling roll, and a tendency which may worsen the external appearance of a raw film may arise.

Since the surface state of the metal to be used is transferred to the surface of the raw film containing polypropylene resin, when the surface has unevenness, the thickness precision of the raw film containing polypropylene resin obtained is used. There is a possibility of lowering. Therefore, it is preferable that the surface of a metal cooling roll is 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, in terms of the standard sequence of maximum heights.

It is preferable that it is 65-80 as the value which the surface hardness of the elastic body in the touch roll which forms a metal cooling roll and a nip part is measured by the spring-type hardness test (A form) prescribed | regulated to JISK 6301, and also 70 It is more preferable that it is -80. By using the rubber roll of such a surface hardness, it becomes easy to maintain the linear pressure applied to a molten-sheet sheet uniformly, and also it does not form the bank (resin reservoir) of a molten-phase sheet between a metal cooling roll and a touch roll, and forms it into a film form. Molding becomes easy.

The pressure (linear pressure) at the time of pinching a molten phase sheet | seat is determined by the pressure which presses a touch roll with respect to a 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 carrying out linear pressure in the said range, it becomes easy to manufacture the raw film containing polypropylene resin, maintaining a constant linear pressure, without forming a bank.

When the biaxially oriented film of the thermoplastic resin is pinched together with the molten sheet sheet of the polypropylene resin between the metal cooling roll and the touch roll, the thermoplastic resin constituting the biaxially oriented film is heat firmly with the polypropylene resin. What is necessary is just resin which does not fuse, and specifically, polyester, polyamide, polyvinyl chloride, polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, polyacrylonitrile, etc. are mentioned. Among these, polyester with few dimensional changes by humidity, heat, etc. is the most preferable. In this case, the thickness of a biaxially stretched film is about 5-50 micrometers normally, Preferably it is 10-30 micrometers.

In this method, the distance (air gap) from the lip of the T die to being pinched by the metal cooling roll and the touch roll is preferably 200 mm or less, and more preferably 160 mm or less. The molten phase sheet extruded from the T die is stretched from the lip to the metal cooling roll, and orientation is likely to occur. By shortening an air gap as mentioned above, a disk film with 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 at the time of manufacturing the raw film containing a polypropylene resin by this method is determined by the time required for cooling and solidifying a molten phase sheet. When the diameter of the metal cooling roll to be used becomes large, since the distance which the molten-phase sheet is contacting with the cooling roll becomes long, manufacture at high speed becomes possible. Specifically, when using a cooling roll made of 600 mmφ metal, the processing speed is at most about 5 to 20 m / min.

The molten phase sheet clamped between the metal cooling roll and the touch roll is cooled and solidified by contact with the metallic cooling roll. And after slitting an edge part as needed, it is wound up by a winder and becomes a disk film. At this time, in order to protect the surface until the master film is used, you may wind up in the state which bonded the surface protection film which consists of another thermoplastic resin to one side or both surfaces. When the molten-phase sheet of polypropylene resin is pinched between the metal cooling roll and the touch roll with the biaxially stretched film which consists of thermoplastic resins, the biaxially stretched film can also be made into one surface protection film.

[Method of producing retardation film]

In the present invention, the retardation film can be produced by lateral stretching of the master film containing the above polypropylene resin. Lateral stretching means extending | stretching the elongate original film wound up from a metal cooling roll in the width direction (lateral direction) here.

Lateral stretching has the following processes normally.

(A) a preheating step of preheating the raw film to the preheating temperature near the melting point of the polypropylene resin;

(B) a stretching step of stretching the preheated master film laterally at a stretching temperature lower than the preheating temperature; And

(C) The heat fixation step of heat fixing the raw film stretched in the transverse direction.

As a typical method of transverse stretching, a tenter method is mentioned. A tenter method is a method of extending | stretching the disc film which fixed both ends of the film width direction by the chuck in the oven, and extending | stretching chuck spacing. The stretching machine (tenter stretching machine) used for a tenter method is equipped with the mechanism which can independently adjust each temperature in the zone which performs a preheating process, the zone which performs a extending process, and the zone which performs a heat fixing process normally. By performing lateral stretching using such a tenter stretching machine, a retardation film having excellent axial accuracy and having a uniform retardation can be obtained.

The preheating step of the lateral stretching is a step provided before the step of stretching the raw film in the width direction, and is a step of heating the raw film to a temperature sufficient to stretch the raw film. The preheating temperature in a preheating process means the atmospheric temperature in the zone which performs the preheating process of oven, and the temperature of melting | fusing point vicinity of the raw film containing the polypropylene resin extended | stretched is employ | adopted. It is preferable that the residence time in the preheating process of the raw film stretched is 30 to 120 second. When the residence time in this preheating step is not satisfied in 30 seconds, the stress is dispersed when the raw film is stretched in the stretching step, which may adversely affect the axial accuracy as the retardation film and the uniformity of the retardation. When the time exceeds 120 seconds, there is a possibility of receiving heat more than necessary to cause the raw film to partially melt and draw down (sag down). As for the residence time in a preheating process, it is more preferable that it is 30 to 60 second.

The stretching process of lateral stretching is a process of extending | stretching a raw film in the width direction. The stretching temperature in this stretching step is usually lower than the preheating temperature. The extending | stretching temperature in an extending process means the atmospheric temperature in the zone which performs the extending process of an oven. By stretching the preheated raw film to a temperature lower than the preheating step, the raw film can be uniformly stretched, and as a result, a retardation film excellent in uniformity of optical axis and retardation can be obtained. It is preferable that extending | stretching temperature is 5-20 degreeC lower than the preheating temperature in a preheating process, and it is more preferable that it is 7-15 degreeC lower. The draw ratio at this time can be suitably selected in accordance with the required phase difference value in a range of about 3 to 10 times in the direction of expressing the optical axis (direction to become the ground axis), and preferably 3 to 6 times Range. By making draw ratio 3 times or more at this time, the said Nz coefficient can be made into the range of 0.9-1.1. On the other hand, if the draw ratio is too large, the uniformity of the phase difference value may be impaired, and therefore it is preferable that the draw ratio is limited to about 10 times.

The heat fixation step of lateral stretching is a step of passing the master film through a zone of a predetermined temperature in an oven while maintaining the film width at the end of the stretching step. In order to effectively improve the stability of optical characteristics, such as retardation and an optical axis of a raw film, it is preferable that heat setting temperature exists in the range from the temperature 5 degreeC lower than the extending | stretching temperature in an extending process to the temperature 30 degreeC higher than extending | stretching temperature.

The process of lateral stretch may further have a heat relaxation process. In the tenter method, this thermal relaxation process is normally performed between an extending process and a heat fixation process, and it is customary that the zone of thermal relaxation is provided so that temperature setting can be performed independently in another zone. Specifically, in the thermal relaxation step, after the raw film is stretched to a predetermined width in the stretching step, the interval between the chucks is narrowed by only a few percent in order to eliminate unnecessary distortion, and usually about 0.5 to 7% smaller than the interval at the end of stretching. Is done.

[Optical characteristics when using as a wave plate]

In this invention, when using a retardation film as a quarter wave plate, it is preferable that the in-plane phase difference value Ro exists in the range of 70-160 nm, and it is more preferable to exist in the range which is 80-150 nm. The quarter wave plate has a function of converting light incident by linearly polarized light into elliptical polarization including circularly polarized light and elliptical polarization including circularly polarized light into linearly polarized light, respectively. On the other hand, in this invention, when using a retardation film as a 1/2 wave plate, it is preferable that the in-plane phase difference value Ro exists in the range of 240-400 nm, and it is more preferable to exist in the range of 260-330 nm. Do. The half wave plate has a function of rotating the direction of linearly polarized light.

[primer]

As a polyolefin resin used as a raw material of a modified polyolefin resin, it is a propylene-alpha-olefin copolymer which copolymerized alpha-olefin to propylene mainly as this, and can select any of a block copolymer and a random copolymer. As an alpha-olefin component, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1- pentene etc. can be illustrated, for example. As for content of a propylene component, 50-90 mol% is optimal, and if it is 50 mol% or less, the adhesiveness with respect to the skin layer of retardation film will fall, and if it is 90 mol% or more, it will become the tendency for the flexibility of retardation film to be insufficient.

In addition, the graft amount of the unsaturated polycarboxylic acid or the derivative of the unsaturated polycarboxylic acid which is a modified monomer in the modified polyolefin resin, and the derivative of (meth) acrylic acid or (meth) acrylic acid is 0.1 to 20% by weight and 0.1 to 30, respectively. It is preferable that it is weight%. When the graft amount is smaller than this range, the solubility in a solvent tends to be lowered. Moreover, when there is more graft amount than this range, there exists a tendency for adhesiveness to polyolefin to fall.

As a derivative of unsaturated polycarboxylic acid or unsaturated polycarboxylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, aconic acid, phthalic acid, trimellitic acid, norbornene dicarboxylic acid Unsaturated polycarboxylic acids, such as an acid, or these derivatives (For example, acid anhydride, an acid halide, an amide, an imide, ester, etc.) are mentioned. In this, itaconic anhydride and maleic anhydride are used, and it is preferable from a viewpoint of the adhesive force with respect to the skin layer of a retardation film that graft amount is 0.1-20 weight%. In addition, these modified monomers can be used individually or in plurality.

Examples of (meth) acrylic acid or derivatives of (meth) acrylic acid include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, and hydroxide. Oxyethyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (Meth) acrylate, stearyl (meth) acrylate, acrylamide, etc. are mentioned. In addition, although these modified monomers can be used individually or in multiple types, from the various film properties of the modified polyolefin resin obtained, it is octyl (meth) acrylate and lauryl (meth) in (meth) acrylic acid or its derivatives in a modified polyolefin resin. It is preferable that at least 1 type of graft amount chosen from an acrylate, a tridecyl (meth) acrylate, and a stearyl (meth) acrylate is 0.1-30 weight%. When the graft amount is smaller than this range, the solvent solubility of the modified polyolefin resin and the adhesive force to the skin layer of the retardation film fall. On the other hand, when too large, the said highly reactive modified monomer forms an ultrahigh molecular weight, and solvent solubility deteriorates, or there exists a tendency for the production amount of the homopolymer or copolymer which does not modify | denature to a polyolefin skeleton to increase.

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 an objective. Monomers usable are copolymerizable unsaturated monomers such as styrene, cyclohexyl vinyl ether and dicyclopentadiene. In addition, it is preferable that the usage-amount of these monomers does not exceed the sum total of the graft amount of a modified monomer.

The method of obtaining modified polyolefin resin using the said modified monomer can be performed by a well-known method. For example, the solution method which heat-dissolves a polyolefin resin in solvents, such as toluene, and adds a modified monomer, or the melting method which adds a modified monomer with the polyolefin resin melted using a Benbury mixer, a kneading machine, an extruder, etc. Etc. can be mentioned. The addition method of a modified monomer may be sequential addition or batch addition.

As a radical generator used for reaction, benzoyl peroxide, di-tert- butyl peroxide, tert- butyl hydroperoxide, dicumyl peroxide, tert- butyl peroxy benzoate, methyl ethyl ketone peroxide, cumene, for example Organic peroxides such as hydroperoxides, and azonitriles such as 2,2'-azobisisobutylnitrile and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile). have.

There is no restriction | limiting in particular in the molecular weight of the polyolefin resin used as a starting material as modified polyolefin resin used for a primer. 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 30,000 to 100,000. If the weight average molecular weight of the modified polyolefin resin is less than 15,000, the adhesion or cohesion force to the skin layer of the retardation film is inferior. If the weight average molecular weight is more than 150,000, the workability and the solubility in the solvent tend to be deteriorated by the viscosity increase.

The primer used by this invention dissolves the said modified polyolefin resin in an organic solvent, and is used. Organic solvents that can be used include aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, nonane, decane, ester solvents such as ethyl acetate and butyl acetate, acetone Ketone solvents, such as methyl ethyl ketone and methyl butyl ketone, Alcohol solvents, such as methanol, ethanol, a propanol, butanol, or these mixed solvents are mentioned. Moreover, it is preferable that solid content concentration of the said modified polyolefin resin solution is 10 to 50 weight%.

Moreover, it is preferable to mix alcohol with modified polyolefin resin as an antifoamer of a primer liquid. Examples of the alcohol include ethanol, 1-propanol, 2-propanol, 1-butanol, and the like. As the resin commercially available as the modified polyolefin resin, for example, "Auron 350T" manufactured by Nippon Seishi, "Auroren S-5106MX", "Auroren S-5189T", "Unnistol P401" by Mitsui Chemicals, "Unnistol P801" (all brand names), etc. are mentioned.

In addition, the method of coating the primer on the retardation film is not particularly limited, and 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 Etc. can be employed. After apply | coating a solution, a solvent is suitably dried and removed, for example, assembling a solvent removal (drying) process by methods, such as a heater heating and a warm air spray.

In addition, when coating the primer layer 30 to the retardation film 20 containing polypropylene resin, it is preferable to perform corona treatment. Thereby, adhesiveness with the retardation film 20 containing the primer layer 30 and polypropylene resin can be improved.

[Adhesive Layer]

As the adhesive layer 40, it can comprise by using an acryl-type polymer, a silicone type polymer, polyester, a polyurethane, a polyether, etc. as a base polymer. Among them, acrylic adhesives are excellent in optical transparency, maintain proper wettability and cohesive force, have excellent adhesiveness with the substrate, and also have weather resistance and heat resistance, and peel off such as lifting or peeling under conditions of heating or humidification. It is preferable to select and use what does not cause a problem.

In an acrylic adhesive, the glass transition temperature includes the alkyl ester of acrylic acid which has a C20 or less alkyl group, such as a methyl group, an ethyl group, and a butyl group, and the functional group containing acrylic monomer containing (meth) acrylic acid, (meth) acrylic-acid hydroxyethyl, etc. Is preferably 25 ° C. or lower, more preferably an acrylic copolymer having a weight average molecular weight of 100,000 or more, which is blended to be 0 ° C. or lower, as the base polymer.

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

Moreover, in this invention, the adhesive containing a light-diffusion agent can be used as an adhesive layer. The light diffusing agent used here may be microparticles | fine-particles which differ in refractive index from the base polymer which comprises the adhesive layer 40, and the microparticles | fine-particles which consist of inorganic compounds, and microparticles | fine-particles which consist of organic compounds (polymers) can be used. Since the base polymer which comprises an acrylic base polymer as mentioned above and which comprises an adhesive layer often shows the refractive index before and after 1.4, the light diffusing agent mix | blended there is suitable from the thing whose refractive index is about 1-2. You can choose. 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 is preferably 0.01 or more and 0.5 or less from the viewpoint of the brightness and visibility of the image display device. The fine particles used as the light diffusing agent are preferably spherical and also close to monodisperse, and for example, fine particles having an average particle diameter in the range of about 2 to 6 μm are preferably used.

As microparticles | fine-particles which consist of an inorganic compound, aluminum oxide (refractive index 1.76), silicon oxide (refractive index 1.45), etc. are mentioned, for example.

Moreover, as microparticles | fine-particles which consist of an organic compound (polymer), for example, melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate / styrene copolymer resin beads (refractive index 1.50-1.59) , 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.

Although the compounding quantity of a light-diffusion agent is suitably determined in consideration of the haze value required for the light-diffusion adhesive layer to which it was mix | blended, the brightness of the image display apparatus to which it is applied, etc., generally, the adhesive layer 40 comprises the adhesive layer 40 It is about 3-30 weight part with respect to 100 weight part of base polymers.

Further, the light diffusing pressure sensitive adhesive layer containing the light diffusing agent ensures the brightness of the image display device to which the elliptical polarizing plate is applied, and has a haze of 20 to 80% in terms of making it difficult to cause blurring or blurring on the display. It is preferable to make it into a range. A haze is prescribed | regulated to JISK7105, and is a value represented by (diffusion transmittance / total light transmittance) x 100 (%).

Although the thickness of an adhesive layer is determined according to the adhesive force etc., it is usually the range of 1-40 micrometers. In order to set it as the thin elliptic polarizing plate which is the objective of this invention, it is preferable to apply thinly in the range which does not impair the characteristics, such as workability and durability. Therefore, it is preferable that the thickness of the adhesive layer is 3 to 25 µm to maintain good workability, to exhibit high durability, to maintain brightness when the image display device is viewed from the front or at an angle, and to cause blurring or blur on the display. This is preferable in view of making it difficult to occur.

[Elliptical Polarizer]

The quarter wave plate can be formed as an elliptical polarizing plate by laminating with the linear polarizing plate at a predetermined axial angle, or laminating with the linear polarizing plate at a predetermined axial angle together with the half wave plate. FIG. 2 (A) and FIG. 2 (B) are diagrams for explaining the relationship between the cross-sectional view showing the layer structure and the axial angle with respect to one embodiment of the elliptical polarizing plate according to the present invention.

Referring to FIG. 2 (A), in one embodiment of the present invention, a linear polarizing plate is used for a phase difference film 10 having a pressure-sensitive adhesive layer comprising a quarter wave plate made of a retardation film containing the above polypropylene resin. It can be set as the elliptical polarizing plate 52 by laminating | stacking on 50). In this case, with reference to FIG. 2 (B), the counterclockwise direction is positive with respect to the absorption axis 22 of the linear polarizing plate 50 to reach the in-plane slow axis 12 of the quarter wave plate. By arrange | positioning so that angle (theta) may be 40-50 degree, Preferably it is almost 45 degree, it will function as a substantially circular polarizing plate. Alternatively, the angle θ that reaches the in-plane slow axis 12 of the quarter wave plate is 130 to 140 degrees, preferably with the counterclockwise direction being positive with respect to the absorption axis 22 of the linear polarizing plate 50. Even if arrange | positioned so that it may be nearly 135 degree | times, it will also function as a nearly circular polarizing plate again. In the following description, the counterclockwise direction is positive with respect to the reference axis in the same manner as described herein.

In addition, with reference to FIG. 3 (A), in another form of this invention, the phase difference film with an adhesive layer containing the 1/4 wavelength plate which consists of a phase difference film containing said polypropylene resin, respectively ( 10) and the half wave plate 25 are laminated | stacked, and the linear polarizing plate 50 can further be laminated | stacked on the half wave plate 25 side, and it can be set as the elliptically polarizing plate 55. FIG. In this case, with reference to FIG. 3 (B), the angle φ that reaches the in-plane slow axis 17 of the half-wave plate 25 is 10 to 10 based on the absorption axis 22 of the linear polarizing plate 50. 20 degrees, Preferably it is about 15 degrees, and the angle (psi) 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 is 55-65 degree, Preferably Preferably, it arrange | positions so that it may be nearly 60 degree, and it will function as a substantially circular polarizing plate. Alternatively, 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, preferably approximately 105 degrees, Even if 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 25 is 55 to 65 degrees, preferably arranged to be approximately 60 degrees, It also almost functions as a circular polarizer. The latter relationship (the angle from the absorption axis of the linear polarizing plate to the in-plane slow axis of the half wave plate 25 is 100 to 110 degrees) shows the straight line of the absorption axis 22 of the linear polarizing plate in FIG. The transmission axis of the polarizing plate corresponds to the state read differently. In the linear polarizing plate, the absorption axis and the transmission axis are orthogonal in plane.

In particular, as shown in Fig. 3 (A), the lamination of the retardation film 10 with the pressure-sensitive adhesive layer including the quarter wave plate and the half wave plate 25 has a wide wavelength range in the visible region. That is, the elliptically polarizing plate 55 in which the linear polarizing plate 50 is laminated on the half-wave plate 25 side of the half wave plate 25 is broadband and has a linearly polarized light as circularly polarized light. Circularly polarized light can be converted into linearly polarized light. Moreover, by configuring in this way, the angle dependence of an antireflection effect can also be reduced.

The linear polarizing plate 50 is an optical element provided with a function of absorbing linearly polarized light having a vibrating surface in a certain direction and transmitting a linearly polarized light having a vibrating surface in a direction orthogonal thereto, and is generally used in this field. Can be used. Specifically, the polyvinyl alcohol linear polarizing plate in which the transparent protective layer was formed in at least one surface of the polarizing film which consists of polyvinyl alcohol-type resin is common. By adsorbing and aligning a dichroic dye to a film of polyvinyl alcohol-based resin, the function of absorbing linearly polarized light having a vibrating surface in any direction described above and transmitting the linearly polarized light having a vibrating surface in a direction orthogonal thereto can be imparted. . As a dichroic dye, iodine or a dichroic organic dye is used. This polarizing film can be obtained by subjecting the film of polyvinyl alcohol-type resin to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment after dyeing.

Although the transparent protective layer of the polarizing plate 50 can be comprised, for example with the film of the acetyl cellulose type resin represented by triacetyl cellulose (TAC) and diacetyl cellulose generally used generally as a protective layer of a polarizing film, In addition, it can also be comprised from the film of cyclic polyolefin resin represented by norbornene-type resin, the film of polypropylene resin, the film of polyethylene terephthalate resin, the film of polymethyl (meth) acrylate, etc.

In addition, as the 1/2 wavelength plate used above, the retardation film containing the said polypropylene resin can also be used, Another conventionally well-known 1/2 wave plate can also be used, It does not specifically limit. As another conventionally well-known 1/2 wave plate, the retardation film containing cyclic polyolefin type resin, the retardation film containing polycarbonate-type resin, etc. are mentioned, for example.

In preparation of an elliptically polarizing plate, an adhesive layer is used for the bonding of the wavelength plate (phase difference film) and the linear polarizing plate 50, and also the bonding of the quarter wave plate and the half wave plate 25, for example. Can be. As an adhesive layer, what mainly uses the acrylic polymer which is excellent in transparency and durability is used preferably. The thickness of an adhesive layer is the range of 5-50 micrometers normally.

The elliptical polarizing plates 52 and 55 comprised as mentioned above can arrange | position an adhesive layer in the surface side of the quarter wave plate, and can be made to be bonded to a liquid crystal cell. The elliptical polarizing plates 52 and 55 are laminated on at least one side of the liquid crystal cell to form a liquid crystal display device. The elliptical polarizing plate may be disposed on both sides of the liquid crystal cell, the elliptical polarizing plate may be disposed on one side of the liquid crystal cell, and another polarizing plate may be disposed on the other side. In bonding to the liquid crystal cell, the quarter wave plate side is disposed so as to face the liquid crystal cell.

[Liquid crystal display device]

In FIG. 4, the elliptically polarizing plate in this invention was arrange | positioned on both surfaces of a liquid crystal cell, and the example which used as a liquid crystal display device is shown with typical sectional drawing, respectively. FIG. 4 shows an elliptically polarizing plate 52 which is a laminate of the phase difference film 10 with the pressure-sensitive adhesive layer including the quarter-wave plate shown in FIG. 2A and the linear polarizing plate 50. The example arrange | positioned at both sides of the figure is shown. That is, in this example, the elliptically polarizing plate 52 including the quarter wave plate / linearly polarizing plate 50 is interposed between the adhesive layer 40 on the lower side of the liquid crystal cell 60, and the quarter wave plate side thereof is the liquid crystal. The elliptically polarizing plate 52 including the quarter wave plate / linear polarizing plate 50 is laminated so as to face the cell 60 and the adhesive layer 40 is disposed on the upper side of the liquid crystal cell 60. 4 wavelength plates are laminated so as to face the liquid crystal cell 60. Each elliptical polarizing plate 52 is disposed so that the absorption axis of the linear polarizing plate 50 is perpendicular to each other. When using this liquid crystal display device as a transmissive type or transflective reflective type, the backlight 70 is disposed outside of the one elliptical polarizing plate 52 (lower side in the drawing).

5 is an elliptically polarizing plate which is a laminate of a phase difference film 10 with a pressure-sensitive adhesive layer including a quarter wave plate shown in FIG. 3 (A), a half wave plate 25, and a linear polarizing plate 50 ( An example in which 55 is disposed on both sides of the liquid crystal cell 60 is shown. That is, in this example, the elliptically polarizing plate 55 made of the quarter wave plate / 1/2 wave plate 25 / linear polarizing plate 50 is interposed with the adhesive layer 40 under the liquid crystal cell 60. The 1/4 wave plate is laminated so as to face the liquid crystal cell 60, and the 1/4 wave plate / 1/2 wave plate 25 / straight line is placed on the upper side of the liquid crystal cell 60 via the pressure-sensitive adhesive layer 40. The elliptical polarizing plate 55 including the polarizing plate 50 is laminated so that the quarter wave plate thereof faces the liquid crystal cell 60. Each elliptical polarizing plate 55 is disposed so that the absorption axis of the linear polarizing plate 50 is perpendicular to each other. When using this liquid crystal display device as a transmissive type or transflective reflective type, the backlight 70 is also arranged outside of the one elliptical polarizing plate (lower side in the drawing).

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,% indicating the content is based on weight unless otherwise specified.

[Retardation Film Made of Polypropylene Resin]

A propylene / ethylene random copolymer ("Sumitomo Nobren W151" manufactured by Sumitomo Chemical Co., Ltd.) containing about 5% of an ethylene unit was formed into a film to obtain a raw film having a thickness of 40 µm. The uniaxial retardation film was obtained by performing horizontal 1st axial stretch of this master film. This retardation film was Ro = 90 nm, Rth = 45 nm, and thickness is 9 micrometers. In addition, the Toray Film Co., Ltd. brand name "tretec 7332" was bonded to one surface of the retardation film containing polypropylene resin 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 the brand name "Auroren S-5189T" manufactured by Nippon Seishi Chemical Co., Ltd., maleic anhydride-modified olefin, to obtain a coating composition. It was.

The molecular weight of aurorene S-5189T is 60000-80000.

Example 1

(a) Lamination of Retardation Film and Primer Layer

Corona discharge treatment was performed on the opposite side to the side where the surface protection film of the retardation film which consists of polypropylene resins is laminated | stacked at the integrated irradiation amount of 15.9 kJ / m <2>. Within 5 minutes after the corona discharge treatment, the primer coating composition was coated on the corona treated surface using a Mayer bar (# 6), dried in an oven at 80 ° C. for 3 minutes, and the primer layer having a thickness of 0.8 μm was retarded. Formed on phase.

(b) Preparation of Elliptical Polarizer

A polarizing plate (SRW062 manufactured by Sumitomo Chemical Co., Ltd.) having a protective film made of triacetyl cellulose is adhered to both surfaces of a polarizing film in which iodine is adsorbed and oriented to polyvinyl alcohol, and urethane acrylate is formed on one side thereof. The sheet-like adhesive [NS300MP sold from Lintec Co., Ltd.] was bonded together, and the polarizing plate with an adhesive was produced. On the other hand, the surface protection film is peeled from the retardation film with the primer layer produced in the above (a), and the corona discharge treatment is performed on the surface (polypropylene resin surface) at an integrated irradiation amount of 15.9 kJ / m 2, and the corona discharge treatment After 5 minutes, the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive produced above was bonded to the corona treated surface thereof. Thereafter, the corona discharge treatment was also performed at the integrated irradiation dose of 15.9 kJ / m 2 on the primer layer side. Within 5 minutes after this corona discharge treatment, an acrylic sheet-like adhesive (P3132 sold by Lintec Co., Ltd.) was bonded to the corona treated surface thereof to obtain an elliptically polarizing plate with an adhesive layer.

(c) Thickness measurement of elliptical polarizer

The thickness was measured for the composite polarizing plate with an adhesive layer obtained by (b) using the digital length measuring instrument "MH-15M" by Nikon Corporation. The results are shown in Table 1 below.

(d) anchoring test

The protective film of the retardation film with a primer layer obtained by (a) was peeled off, and the corona discharge process was given to the surface on the conditions of the integrated irradiation amount of 15.9 kJ / m <2>. Furthermore, corona discharge treatment was performed to biaxial thermoplastic saturated norbornene resin (ZB055124 manufactured by Nippon Xeon Co., Ltd.) under conditions of an integrated irradiation amount of 15.9 kJ / m 2. Within 10 minutes after the corona discharge treatment, an active energy ray curable resin composition containing an epoxy compound is coated on the corona treated surface of the biaxial thermoplastic saturated norbornene resin by using a Mayer bar (# 1), and the coated surface thereof. And the corona-treated surface of the retardation film with a primer layer were bonded together, and were UV-cured at 500 mW / 1500 mJ by the UV irradiation apparatus by a FUSION company. Subsequently, after performing a corona discharge treatment at the integrated irradiation amount of 15.9 kJ / m <2> on the surface of a primer layer, within 5 minutes after a corona discharge treatment, the acrylic adhesive (P3132 sold from Lintec) is bonded to the corona treatment surface, The retardation film with an adhesive was produced, and the film for adhesive evaluation was produced. Then, it was left to stand for 1 day in the atmosphere of the temperature of 23 degreeC, and 60% RH of humidity. This adhesive evaluation film was cut | disconnected to 25 mm in width and about 200 mm in length, and the adhesive force of 3 points | pieces was evaluated in the longitudinal direction using the said "Adhesion evaluation apparatus" by the said Nippon System Group Corporation. The evaluation used the styrene rubber of 60 degree hardness, and obtained the 3-point average of the length which the adhesive layer peeled from the coating retardation layer when it slid 20 times in a fixed direction, pressing at the pressure of 0.4 MPa, as peeling distance. In addition, the measurement was performed in the atmosphere of the temperature of 23 degreeC, and 60% RH of humidity. The results are shown in Table 1.

(e) Glass plate sticking peeling test

The film for evaluation of adhesiveness obtained in the above (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 the pressure was reduced to 20 at a pressure of 5 kgf / cm 2 and a temperature of 50 ° C in an autoclave. Pressurization was performed for minutes, and it was left to stand for 1 day in the atmosphere of the temperature of 23 degreeC, and humidity of 60% RH. Peeling was carried out using a universal tensile tester (AG-1, manufactured by Shimadzu Co., Ltd.) at 90 ° peel test at a crosshead speed of 200 mm / min under a temperature of 23 ° C. and 60% RH. Evaluated by. In addition, the measurement was performed in the atmosphere of the temperature of 23 degreeC, and 60% RH of humidity.

In Table 1, the peelable symbol is shown below.

Good: The pressure-sensitive adhesive layer could be peeled off without remaining on the glass plate.

Poor: The adhesive layer remained on the glass plate and peeled.

[Primer 2]

30 parts of toluene and 10 parts by weight of 2-propanol as an antifoaming agent are added to 40 parts by weight of the Nippon Seishi Chemical Co., Ltd. product name "Aurorene 250-MX" which is a maleic anhydride modified olefin as a primer, and is a coating composition It was set as. The molecular weight of the aurorene 250-MX is 60000 to 80000.

Example 2

(a) Lamination of Retardation Film and Primer Layer

Corona discharge treatment was performed on the opposite side to the side where the surface protection film of the retardation film which consists of polypropylene resins is laminated | stacked at the integrated irradiation amount of 15.9 kJ / m <2>. Within 5 minutes after the corona discharge treatment, the primer 2 coating composition was coated on the corona treated surface thereof using a Mayer bar (# 14), dried in an oven at 80 ° C. for 5 minutes, and the primer layer having a thickness of 1.0 μm was retarded. Formed on film.

(b) Preparation of Elliptical Polarizer

An elliptical polarizing plate was produced in the same manner as in Example 1.

(c) Thickness measurement of elliptical polarizer

It measured in the same manner as in Example 1. The measurement results are shown in Table 1.

(d) anchoring test

(e) Glass plate sticking peeling test

[Primer 3]

3 parts by weight of 2-propanol was added as an antifoaming agent to 100 parts by weight of the Nippon Seishi Chemical Co., Ltd. product name "Aurorene 350T" which is a maleic anhydride modified olefin as a primer, and it was set as the coating composition. The molecular weight of the aurorene 350T is 60000-80000.

Example 3

(a) Lamination of Retardation Film and Primer

Corona discharge treatment was performed on the opposite side to the side where the surface protection film of the retardation film which consists of polypropylene resins is laminated | stacked at the integrated irradiation amount of 15.9 kJ / m <2>. Within 5 minutes after the corona discharge treatment, the primer 3 coating composition was coated on the corona treated surface thereof using a Mayer bar (# 3), dried in an oven at 80 ° C. for 3 minutes, and the primer layer having a thickness of 0.8 μm was retarded. Formed on film.

(b) Preparation of Elliptical Polarizer

An elliptical polarizing plate was produced in the same manner as in Example 1.

(c) Thickness measurement of elliptical polarizer

(d) anchoring test

(e) Glass plate sticking peeling test

[Primer 4]

3 parts by weight of 2-propanol was added as an antifoaming agent to a coating composition based on 100 parts by weight of the brand name "Aurorene S-5106-MX" manufactured by Nippon Seishi Chemical Co., Ltd., a maleic anhydride-modified olefin as a primer. . The molecular weight of the aurorene S-5106-MX is 60000 to 80000.

Example 4

(a) Lamination of Retardation Film and Primer

Corona discharge treatment was performed on the opposite side to the side where the surface protection film of the retardation film which consists of polypropylene resins is laminated | stacked at the integrated irradiation amount of 15.9 kJ / m <2>. Within 5 minutes after the corona discharge treatment, the primer 4 coating composition was coated on the corona treated surface thereof using a Mayer bar (# 3), dried in an oven at 80 ° C. for 3 minutes, and the primer layer having a thickness of 0.8 μm was retarded. Formed on film.

(b) Preparation of Elliptical Polarizer

An elliptical polarizing plate was produced in the same manner as in Example 1.

(c) Thickness measurement of elliptical polarizer

(d) anchoring test

(e) Glass plate sticking peeling test

Comparative Example 1

(a) Preparation of retardation film without primer layer

The corona discharge treatment was given to the surface with the integrated irradiation amount of 15.9 kJ / m <2> on the retardation film which consists of polypropylene. Within 5 minutes after this corona discharge treatment, an acrylic adhesive (P3132 sold by Lintec Co., Ltd.) was bonded to the corona treatment surface.

(b) Preparation of Elliptical Polarizer

An elliptical polarizing plate was produced in the same manner as in Example 1.

(c) Thickness measurement of elliptical polarizer

In the same manner as in Example 1, the thickness of the elliptical polarizing plate was measured. The results are shown in Table 1.

(d) anchoring test

The anchoring force was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(e) Glass plate sticking peeling test

Peelability was evaluated in the same manner as in Example 1.

The disclosed embodiments and examples are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is indicated by the claims rather than the foregoing description, and is intended to include any modifications within the scope and meaning equivalent to the claims.

According to this invention, the retardation film containing a polypropylene resin, the retardation film with an adhesive layer which can improve adhesiveness with an adhesive layer can be provided.

Claims

The retardation film 20, the primer layer 30, and the adhesive layer 40 which consist of polypropylene resin are formed in this order, and the said primer layer 30 is unsaturated polycarboxylic acid or unsaturated polycarboxylic acid. A phase difference film with a pressure-sensitive adhesive layer, comprising a modified polyolefin resin having a weight average molecular weight of 15,000 to 150,000 and a derivative of (meth) acrylic acid or a derivative of (meth) acrylic acid.

The retardation film with an adhesive layer of Claim 1 in which the retardation film (20) containing the said polypropylene resin consists of a copolymer of propylene and ethylene containing 10 weight% or less of ethylene units.

The retardation film with an adhesive layer of Claim 1 whose said retardation film (20) is a quarter wave plate.

The elliptical polarizing plate containing the polarizing plate 50 and the phase difference film 10 with an adhesive layer of Claim 1 laminated | stacked on the said polarizing plate 50.

The elliptic polarizing plate according to claim 4, further comprising a half wave plate (25) between the phase difference film (10) having the pressure-sensitive adhesive layer and the polarizing plate (50).

The liquid crystal display device in which the elliptical polarizing plate of Claim 4 is laminated | stacked on at least one side of the liquid crystal cell (60).