KR101483328B1 - Acrylic resin-containing film, process for producing acrylic resin-containing film, and polarizing plate and liquid crystal display device using the acrylic resin-containing film - Google Patents

Abstract

An object of the present invention is to provide an acrylic resin-containing film excellent in transparency, high in heat resistance and remarkably improved in brittleness. Further, by using the acrylic resin-containing film, it is possible to improve the yield in operations such as punching operation of a polarizing plate and panel joining, decrease the color shift caused by viewing angle, and further improve the contrast, A display device is provided. The acrylic resin-containing film of the present invention is an acrylic resin-containing film containing 10 to 50 parts by mass of a cellulose ester resin (B) relative to 50 to 90 parts by mass of the acrylic resin (A) And has a coefficient of static friction of 0.3 to 0.8, a softening point of tension of 105 to 145 占 폚, and a haze value of less than 1%, and does not cause ductile fracture.

Description

TECHNICAL FIELD [0001] The present invention relates to an acrylic resin-containing film, a method of producing an acrylic resin-containing film, a polarizing plate using the same, and a liquid crystal display device using the acrylic resin- }

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an acrylic resin-containing film mainly composed of an acrylic resin, a polarizing plate using the acrylic resin, and a display device, and more particularly to an acrylic resin-containing film blended with an acrylic resin and a cellulose ester resin, The present invention relates to a liquid crystal display device which improves the yield in operations such as panel joining, reduces the color shift caused by viewing angle, and further improves the contrast.

(Hereinafter abbreviated as PMMA) which is a representative of conventional acrylic resins has been suitably used as an optical film from the viewpoints of its excellent transparency, dimensional stability, low hygroscopicity and the like.

However, the PMMA film has insufficient heat resistance and has a problem that the shape changes in use at a high temperature and in long-term use.

For solving this problem, a method of using a film in which an acrylic resin and a cellulose ester resin are blended is disclosed (for example, see Patent Document 1 below). However, in the example of this document, since cellulose resin having a low molecular weight is used from the viewpoint of compatibility of acrylic resin and cellulose resin, there is a problem that the film is fragile and fragile.

On the other hand, an invention has been disclosed in which silicone-based fine particles are added to a cellulose ester film to improve light transmittance and light resistance (see, for example, Patent Document 2 below). However, since the added fine particles aggregate to cause haze or compatibility with the UV agent, they are difficult to use.

Further, there is disclosed an invention in which heat-resistant protective layer is formed on at least a part of a surface of a cellulose ester film so as to be peelable (for example, refer to Patent Document 3 below) It is too much. Further, an invention has been disclosed in which a matting agent is added in order to suppress the occurrence of scratch failures during winding of a cellulose ester film without lowering the transmittance of the cellulose ester film (see, for example, Patent Document 4). In this case, excessive amount of the matting agent causes haze, so that the amount of the matting agent to be added is limited, and the above object can not be sufficiently achieved.

Further, in order to improve the surface physical properties accompanying the thinning of the cellulose ester film and the protruding dull defects when rolled in the roll form, the surface roughness of the cellulose ester film, the amount of the mat agent present, the amount of the plasticizer present, (See, for example, Patent Document 5 below). However, according to this method, there is a problem that the curl, the dimensional change, the refractive index of the surface and the inside are different, and the front contrast (hereinafter also referred to as CR) is lowered.

Japanese Unexamined Patent Application Publication No. 5-119217 Japanese Patent Application Laid-Open No. 7-11056 Japanese Patent Laid-Open No. 2001-105749 Japanese Patent Laid-Open No. 2002-317059 Japanese Patent Application Laid-Open No. 2004-168981

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an acrylic resin-containing film which is excellent in transparency, has high heat resistance and remarkably improved in brittleness. Further, by using the acrylic resin-containing film, it is possible to improve the yield in operations such as punching operation of a polarizing plate and panel joining, decrease the color shift caused by viewing angle, and further improve the contrast, And a display device.

The above object of the present invention can be achieved by the following arrangement.

1. An acrylic resin-containing film containing 10 to 50 parts by mass of a cellulose ester resin (B) relative to 50 to 90 parts by mass of an acrylic resin (A), wherein one side of the acrylic resin- , A static friction coefficient of 0.3 to 0.8, a tensile softening point of 105 to 145 占 폚, a haze value of less than 1%, and no ductile fracture.

Wherein the acrylic resin (A) of the acrylic resin-containing film has a weight average molecular weight (Mw) of 80000 to 1000000, a total substitution degree (T) of the acyl group of the cellulose ester resin (B) is 2.00 to 3.00, (Ac) of 0.10 to 1.90, a portion other than the acetyl group is substituted with an acyl group having a carbon number of 3 to 7, a degree of substitution (r) thereof is from 1.10 to 2.90 and a weight average molecular weight (Mw) (C) in an amount of 0.05 to 45% by mass relative to the total mass of the film, and the acrylic fine particles are contained in an area within 25% of the thickness of the entire film from both surfaces of the film , And the acrylic resin-containing film according to the above-mentioned 1, wherein 40 to 60% of the total amount thereof is present.

3. A method for producing an acrylic resin-containing film, wherein the acrylic resin-containing film according to 1 or 2 above is stretched by 5% to 40% in at least one direction.

4. A polarizing plate characterized by using the acrylic resin-containing film according to 1 or 2 above.

5. A liquid crystal display device characterized by using the polarizing plate described in 4 above.

6. A polarizing plate characterized by using the film produced by the method for producing an acrylic resin-containing film according to 3 above.

7. A liquid crystal display device using the polarizing plate according to 6. above.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an acrylic resin-containing film which is transparent, has high heat resistance and remarkably improved in brittleness, and can provide a liquid crystal display device in which the color shift is reduced and the contrast is remarkably improved.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing a dope manufacturing process, a softening process and a drying process of a solution casting film-forming method used in the present invention. Fig.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

Disclosure of Invention Technical Problem [8] The present invention is an improvement of the properties that the shape is easily changed and the brittleness is deteriorated, which is a shortcoming of the conventional acrylic resin-containing film and is insufficient in heat resistance and is used under high temperature, B) is blended, an acrylic resin-containing film which is transparent, has high heat resistance and remarkably improves the embrittlement can be obtained, and the present invention is accomplished.

It has been found that a film having a tensile softening point of 105 to 145 占 폚 and not causing ductile fracture satisfies the heat resistance required for an optical film used in a liquid crystal display device or the like.

≪ Acrylic resin-containing film &

The acrylic resin-containing film of the present invention is characterized by having a haze value of less than 1%, a tensile softening point of 105 to 145 ° C, and a coefficient of static friction of 0.3 to 0.8 when one side is superimposed on the other side .

The coefficient of static friction when one surface of the acrylic resin-containing film of the present invention is superimposed on the other surface is 0.3 to 0.8. When the film is in this range, when the film is wound around the center of the core and stored for a long period of time, the films do not stick to each other and damage the smoothness and the appearance, and can be smoothly fed out from the winding. Also, in this range, the films tend to slide very easily, and when they are wound, they do not protrude in a so-called bamboo shoot shape, and there is no fear of deteriorating the quality. It is also possible to obtain a long film of 4000 to 6000 m by controlling the coefficient of static friction to 0.3 to 0.8.

The acrylic resin-containing film according to the present invention has a low tensile softening point and a high softening point of 105 to 145 占 폚 in consideration of use in a high temperature environment such as a high temperature apparatus such as a projector or a vehicle- do. It is more preferable to control the temperature to 110 to 130 占 폚. By controlling the tension softening point within the above range, it is possible to continuously display a clear image when the liquid crystal display using the film is used for a long time. With this range, there is no possibility that the image quality, color taste and the like of the display device will be damaged in long-term use, depending on the use environment, and there is no need to use an acrylic resin having extremely high heat resistance.

As a specific method of measuring the tensile softening point temperature of an acrylic resin-containing film, an acrylic resin-containing film is cut to 120 mm (length) x 10 mm (width) using a tensilon tester (RTC-1225A manufactured by ORIENTEC Co., Ltd.) The temperature is maintained at a temperature raising rate of 30 캜 / min while pulling with a tensile force of 10 N, and the temperature at the time when the temperature reaches 9 N is measured three times, and the average value is obtained.

Further, the acrylic resin-containing film of the present invention is characterized by being an acrylic resin film which does not cause ductile fracture.

The soft fracture in the present invention is defined as a fracture which is caused by the action of a stress larger than that of an arbitrary material and is accompanied by remarkable elongation or contraction of the material until the final fracture. In its wavefront, there is a feature that a depression called a dimple is formed infinitely. Therefore, " acrylic resin film in which ductile fracture does not occur " is characterized in that breakage such as breakage can not be seen even when a large stress is applied to bend the film into two.

In recent years, with the increase in the size of liquid crystal display devices, demands for brittleness of the optical film from the viewpoint of rewiring property and productivity have been increasing with the increase in the thickness of the optical film and thinning of the optical film, and it is required that the ductile fracture does not occur.

In order to form an acrylic resin film in which ductile fracture does not occur, it is achieved by appropriately selecting the material constitution such as acrylic resin, cellulose ester, acrylic fine particles and other additives to be used.

The acrylic resin-containing film of the present invention preferably has a glass transition temperature (Tg) of 110 DEG C or higher. More preferably, it is 120 DEG C or more. Particularly preferably 150 ° C or higher.

The glass transition temperature is measured by a differential scanning calorimeter (DSC-7 made by Perkin Elmer) at a heating rate of 20 ° C / min. The glass transition temperature is measured by a mid-point glass transition temperature determined according to JIS K7121 (1987) Temperature (Tmg).

The acrylic resin-containing film of the present invention is one or less defects each having a diameter of 5 m or more in the film plane per square of 10 cm in one side. More preferably no more than 0.5 per square of a 10 cm side, and more preferably no more than 0.1 per square of a side with a side of 10 cm.

Here, the diameter of the defect refers to the diameter of the defect when the defect is circular, and the range of the defect when it is not circular is determined by observing with a microscope by the following method, and the maximum diameter thereof (diameter of the circumscribed circle) is determined.

When the defects are bubbles or foreign matter, the range of the defects is the size of the shadows when the defects are observed with the transmitted light of the differential interference microscope. If the defect is a change in surface shape such as transfer of roll damage or scratches, check the size of the defect by observing it with reflected light from a differential interference microscope.

In the case of observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface and observed.

In order to obtain a film having excellent durability represented by such defect frequency with high productivity, it is necessary to perform high-precision filtration of the polymer solution just before bending, to increase the degree of cleanliness around the fume chamber, to set the drying conditions after bending stepwise, It is effective to effectively suppress the foaming and to dry it.

If the number of defects is more than one per square of 10 cm on one side, for example, if the film is subjected to a tensile force at the time of processing in a subsequent step, etc., the film may break at the beginning of the defect, resulting in a marked decrease in productivity. When the diameter of the defect is 5 mu m or more, it can be visually confirmed by observing the polarizing plate and the like, and a bright spot sometimes occurs when used as an optical member.

Further, even when the film can not be visually confirmed, a coating agent can not be uniformly formed when a hard coat layer or the like is formed on the film, resulting in a defect (coating missing). Here, the defect refers to a defect in a film caused by rapid evaporation of a solvent in the step of drying a solution film, a foreign matter in a stock solution of the film forming solution or a foreign matter contained in a film, Defects).

Further, in the acrylic resin-containing film of the present invention, in the measurement according to JIS-K7127-1999, the elongation at break in at least one direction is preferably 10% or more, and more preferably 20% or more.

The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film due to foreign substances or foaming.

The thickness of the acrylic resin-containing film of the present invention is preferably 20 占 퐉 or more. More preferably 30 mu m or more.

Although the upper limit of the thickness is not particularly limited, when the film is formed by a solution casting method, the upper limit is about 250 탆 from the viewpoint of coatability, foaming, solvent drying and the like. The thickness of the film can be appropriately selected depending on the application.

The acrylic resin-containing film of the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more. The practical upper limit is about 99%. In order to achieve excellent transparency expressed by the total light transmittance, it is necessary to prevent introduction of an additive or a copolymerizable component that absorbs visible light and to remove foreign substances in the polymer by high-precision filtration to reduce diffusion or absorption of light inside the film It is valid.

It is also possible to reduce the surface roughness of the film contacting portion (such as a cooling roll, a calender roll, a drum, a belt, a coating base in a solution casting process, a transport roll, etc.) during film formation to reduce the surface roughness of the film surface, It is effective to reduce the diffusion and reflection of light on the surface of the film.

The acrylic resin-containing film of the present invention is characterized by having a haze value (turbidity) of 1.0% or less which is one of indexes showing transparency, but is preferably 0.5% or less from the viewpoint of brightness and contrast when assembled into a liquid crystal display device .

In order to achieve such a haze value, it is effective to remove foreign matter in the polymer by high-precision filtration to reduce the diffusion of light inside the film.

In the case of using the acrylic fine particles, it is also effective to reduce the refractive index difference between the acrylic resin (A) and the acrylic fine particles (C).

The surface roughness also affects the haze value as the surface haze. Therefore, it is also effective to suppress the particle diameter and the addition amount of the acrylic fine particles (C) within the above range, or reduce the surface roughness of the film contacting portion at the time of film formation.

The total light transmittance and haze value of the acrylic resin-containing film are values measured according to JIS-K7361-1-1997 and JIS-K7136-2000.

The acrylic resin-containing film of the present invention can be preferably used as an acrylic resin-containing film for optical purposes if it satisfies the above physical properties, but a film excellent in workability and heat resistance can be obtained by the following composition.

That is, it is preferable that the acrylic resin-containing film contains the acrylic resin (A) and the cellulose ester resin (B) in a mass ratio of 90:10 to 50:50, and the cellulose ester resin (B (Ac) of 0.10 to 1.90, the number of carbon atoms of the acyl group other than the acetyl group is 3 to 7, and the degree of substitution (r) of the acyl group is 1.10 To 2.90 and a weight average molecular weight (Mw) of 75000 to 280000 can be obtained by the acrylic resin-containing film.

In the acrylic resin-containing film of the present invention, the acrylic resin (A) and the cellulose ester resin (B) are contained in a mass ratio of 90:10 to 50:50, but preferably the acrylic resin (A) is 70% .

When the amount of the acrylic resin component is large, for example, the dimensional change under high temperature and high humidity is suppressed, and the curl of the polarizing plate and the warp of the polarizing plate when used as the polarizing plate can be remarkably reduced. Further, in the composition having an acrylic resin component of 70 mass% or more, it is possible to maintain the physical properties for a longer time.

The acrylic resin-containing film of the present invention may contain a resin other than the acrylic resin (A) and the cellulose ester resin (B).

The total mass of the acrylic resin (A) and the cellulose ester resin (B) is 55 to 100 mass%, preferably 60 to 99 mass%, of the acrylic resin-containing film.

≪ Acrylic resin (A) >

The acrylic resin used in the present invention also includes methacrylic resin. The resin is not particularly limited, but it is preferably composed of 50 to 99 mass% of methyl methacrylate units and 1 to 50 mass% of other monomer units copolymerizable therewith.

Examples of other copolymerizable monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms in the alkyl group, alkyl acrylates having 1 to 18 carbon atoms in the alkyl group, alpha, beta -unsaturated acids such as acrylic acid and methacrylic acid, Styrene,? -Methylstyrene, and nuclear substituted styrene;?,? - unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as maleic anhydride, Maleimide, N-substituted maleimide, and glutaric anhydride. These may be used singly or in combination of two or more.

Of these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, and 2-ethylhexyl acrylate are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer , Methyl acrylate or n-butyl acrylate are particularly preferably used.

The acrylic resin (A) used in the acrylic resin-containing film of the present invention preferably has a weight average molecular weight (Mw) of from 80000 to 1000000 in terms of mechanical strength as a film and fluidity in producing a film.

The weight average molecular weight of the acrylic resin of the present invention can be measured by gel permeation chromatography. The measurement conditions are as follows.

Solvent: methylene chloride

Column: Shodex K806, K805, K803G (connected by using three connections manufactured by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: standard curve A calibration curve with 13 samples of polystyrene STK standard polystyrene (manufactured by TOSOH CORPORATION) Mw = 2,800,000 to 500 was used. 13 samples are preferably used at substantially equal intervals.

In the present invention, the production method of the acrylic resin (A) is not particularly limited, and any of known methods such as suspension polymerization, emulsion polymerization, bulk polymerization or solution polymerization may be used. As the polymerization initiator, a conventional peroxide-based or azo-based agent can be used, and a redox system can also be used. The polymerization temperature may be 30 to 100 占 폚 for suspension or emulsion polymerization and 80 to 160 占 폚 for bulk polymerization or solution polymerization. In order to control the reduced viscosity of the resulting copolymer, polymerization may also be carried out using alkylmercaptan or the like as a chain transfer agent.

By making this molecular weight, compatibility between heat resistance and brittleness can be achieved.

As the acrylic resin of the present invention, commercially available acrylic resins may also be used. (Manufactured by Asahi Kasei Chemicals Corporation), Dianal BR52, BR80, BR83, BR85 and BR88 (manufactured by Mitsubishi Rayon Co., Ltd.) and KT75 (manufactured by Denki Kagaku Kogyo Co., Ltd.) And the like.

≪ Cellulose ester resin (B) >

The cellulose ester resin (B) of the present invention may be substituted with an aliphatic acyl group or an aromatic acyl group, but is preferably substituted with an acetyl group.

When the cellulose ester resin (B) of the present invention is an ester with an aliphatic acyl group, the aliphatic acyl group has 2 to 20 carbon atoms and specifically includes acetyl, propionyl, butyryl, isobutyryl, valeryl, Hexanoyl, octanoyl, lauroyl, stearoyl and the like.

In the present invention, the aliphatic acyl group also includes those having a substituent. Examples of the substituent include those exemplified as substituents of the benzene ring when the aromatic ring is a benzene ring in the above-mentioned aromatic acyl group.

When the cellulose ester resin (B) is an ester with an aromatic acyl group, the number of substituents X to be substituted in the aromatic ring is 0 or 1 to 5, preferably 1 to 3, and particularly preferably 1 or 2.

When the number of the substituents on the aromatic ring is two or more, they may be the same or different and may also be connected to each other to form a condensed polycyclic compound (for example, naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, , Chroman, phthalazine, acridine, indole, indoline, etc.) may be formed.

The cellulose ester resin (B) has a structure having at least any one selected from the group consisting of a substituted or unsubstituted aliphatic acyl group and a substituted or unsubstituted aromatic acyl group, is used as the structure used in the cellulose resin of the present invention, Cellulose may be used alone or as mixed acid ester.

The substitution degree of the cellulose ester resin (B) of the present invention is preferably such that the acetyl group substitution degree (ac) is 0.10 to 1.90, Do. More preferably, the degree of substitution (r) of the acyl group other than the acetyl group is from 1.10 to 2.90.

The acyl group other than the acetyl group preferably has 3 to 7 carbon atoms.

In the cellulose ester resin (B) of the present invention, those having an acyl group having 3 to 7 carbon atoms as a substituent, that is, a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose acetate benzoate , And cellulose benzoate.

Among these, particularly preferred cellulose ester resins (B) include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate and cellulose acetate butyrate.

The mixed fatty acid is more preferably a lower fatty acid ester of cellulose acetate propionate or cellulose acetate butyrate and has an acyl group having 3 to 4 carbon atoms as a substituent.

The part not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by a known method.

The substitution degree of the acetyl group or the substitution degree of the other acyl group is obtained by the method defined in ASTM-D817-96.

The weight average molecular weight (Mw) of the cellulose ester resin (B) of the present invention can achieve the object of the present invention even if it has a weight average molecular weight (Mw) of 75,000 or more, but it is preferably 75,000 to 280,000, To 240000.

≪ Acrylic fine particles (C) >

In the present invention, the acrylic resin-containing film may contain acrylic fine particles.

The acrylic fine particles (C) according to the present invention are characterized by being present in the form of particles in the acrylic resin (A), the cellulose ester resin (B) and the acrylic resin-containing film (also referred to as an emergency state).

The acrylic fine particles (C) are obtained by, for example, taking a predetermined amount of the prepared acrylic resin-containing film, dissolving in a solvent and stirring the resultant, and sufficiently dissolving and dispersing the acrylic fine particles (C) , And the weight of the insoluble matter collected by filtration is preferably 90% by mass or more of the acrylic fine particles (C) added to the acrylic resin-containing film.

The acrylic fine particles (C) used in the present invention are not particularly limited, but are preferably acrylic fine particles (C) having a layer structure of two or more layers, particularly preferably the following multi-layer structure acrylic granular composite.

The multi-layered acrylic granular composite refers to a particulate acrylic polymer having a structure in which the innermost hard layer polymer, the crosslinked soft layer polymer exhibiting rubber elasticity and the outermost hard layer polymer are laminated in layers from the central portion toward the outer peripheral portion .

Preferred examples of the multi-layered acrylic particulate composite used in the acrylic resin composition of the present invention include the following. (a) a monomer mixture comprising 80 to 98.9 mass% of methyl methacrylate, 1 to 20 mass% of an alkyl acrylate having an alkyl group of 1 to 8 carbon atoms, and 0.01 to 0.3 mass% of a multi-functional graft, (B) from 75 to 98.5% by weight of an alkyl acrylate having from 4 to 8 carbon atoms in the alkyl group, from 0.01 to 5% by weight of a polyfunctional crosslinking agent and from 0.5 to 5% by weight of a polyfunctional grafting agent in the presence of the innermost hard layer polymer, (C) a polymer comprising 80 to 99% by mass of methyl methacrylate and 1 to 8% by number of alkyl groups having 1 to 8 carbon atoms in the alkyl group in the presence of the polymer comprising the innermost hard layer and the crosslinked soft layer, Acrylate, and 1 to 20% by mass of an acrylate. And the obtained three-layer structure polymer is composed of 5 to 40 mass% of the innermost hard layer polymer (a), 30 to 60 mass% of the soft layer polymer (b), and 20 to 50 mass% of the outermost hard layer polymer An acrylic granular complex having an insoluble portion when fractionated by acetone and a degree of methyl ethyl ketone swelling of an insoluble portion of 1.5 to 4.0.

Furthermore, as disclosed in Japanese Patent Publication No. 60-17406 or Japanese Patent Publication No. 3-39095, the composition and particle diameter of each layer of the multi-layered acrylic particulate composite are specified, By setting the tensile elastic modulus of the granular composite or the methyl ethyl ketone swelling degree of the acetone insoluble portion within a specific range, it is possible to realize a balance of sufficient impact resistance and stress relaxation whitening resistance.

Here, the innermost hard layer polymer (a) constituting the multi-layer structure acrylic granular composite preferably contains 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of an alkyl acrylate having an alkyl group of 1 to 8 carbon atoms and a multi- 0.01 to 0.3% by mass of the monomer mixture.

Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, And methyl acrylate or n-butyl acrylate is preferably used.

The proportion of the alkyl acrylate unit in the innermost hard layer polymer (a) is 1 to 20% by mass, and when the unit is less than 1% by mass, the thermal decomposition property of the polymer is increased. On the other hand, , The glass transition temperature of the innermost hard layer polymer (c) is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite is lowered.

Examples of the multifunctional grafting agent include multifunctional monomers having different polymerizable functional groups such as acrylic acid, methacrylic acid, maleic acid, and allyl esters of fumaric acid, and allyl methacrylate is preferably used. The multifunctional grafting agent is used for chemically bonding the innermost hard layer polymer and the soft layer polymer, and the ratio used in the polymerization of the innermost hard layer is 0.01 to 0.3 mass%.

The crosslinked soft layer polymer (b) constituting the acrylic granular composite is obtained by polymerizing, in the presence of the innermost hard layer polymer (a), from 75 to 98.5% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, And 0.5 to 5% by mass of a multifunctional grafting agent.

As the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group, n-butyl acrylate and 2-ethylhexyl acrylate are preferably used.

It is also possible to copolymerize other monofunctional monomers copolymerizable with these polymerizable monomers at 25 mass% or less.

Examples of other monofunctional monomers capable of copolymerization include styrene and substituted styrene derivatives. The ratio of the alkyl acrylate having the alkyl group of 4 to 8 carbon atoms to the styrene is such that the more the electrons are present, the lower the glass transition temperature of the produced polymer (b), that is, the softened.

On the other hand, from the viewpoint of transparency of the resin composition, it is more advantageous if the refractive index of the soft layer polymer (b) at room temperature is close to the innermost hard layer polymer (a), the outermost hard layer polymer (c) and the hard thermoplastic acrylic resin , And the ratio of the two is selected in consideration of these.

For example, in applications where the coating layer thickness is small, styrene may not necessarily be copolymerized.

As the multifunctional grafting agent, those exemplified in the paragraph of the innermost hard layer polymer (a) may be used. The multifunctional grafting agent used here is used for chemically bonding the soft layer polymer (b) and the outermost hard layer polymer (c), and the ratio used in the polymerization of the innermost hard layer is 0.5 By mass to 5% by mass.

As the polyfunctional crosslinking agent, generally known crosslinking agents such as a divinyl compound, a diallyl compound, a diacryl compound and a dimethacryl compound can be used, but polyethylene glycol diacrylate (molecular weight: 200 to 600) is preferably used.

The multifunctional crosslinking agent used herein is used for producing a crosslinked structure at the time of polymerization of the soft layer (b) and exhibiting the effect of imparting impact resistance. However, when the above-mentioned multifunctional grafting agent is used at the time of polymerization of the soft layer, a cross-linking structure of the soft layer (b) is generated to a certain extent. Therefore, a polyfunctional crosslinking agent is not an essential component, Is preferably from 0.01 to 5% by mass from the viewpoint of the impact-imparting effect.

The outermost hard layer polymer (c) constituting the multi-layer structure acrylic granular composite is produced by mixing, in the presence of the innermost hard layer polymer (a) and the soft layer polymer (b), 80 to 99% by mass of methyl methacrylate, And 1 to 20% by mass of an alkyl acrylate having 1 to 8 carbon atoms.

Here, as the alkyl acrylate, the above-mentioned ones are used, but methyl acrylate and ethyl acrylate are preferably used. The ratio of the alkyl acrylate units in the outermost hard layer (c) is preferably from 1 to 20% by mass.

In order to improve the compatibility with the acrylic resin (A), it is also possible to use alkylmercaptan or the like as a chain transfer agent for controlling the molecular weight at the time of polymerization of the outermost hard layer (c).

In particular, it is preferable in the outermost hard layer to provide a gradient in which the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance. As a specific method, it is possible to reduce the molecular weight from the inside toward the outside by dividing the monomer mixture for forming the outermost hard layer into two or more and sequentially increasing the amount of the chain transfer agent to be added at each time.

The molecular weight to be formed at this time can also be measured by polymerizing the monomer mixture used for each cycle alone under the same conditions and measuring the molecular weight of the obtained polymer.

The particle diameter of the acrylic particulate composite which is preferably used in the present invention is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, particularly preferably 50 nm or more, And most preferably 400 nm or less.

In the acrylic particulate composite which is preferably used in the present invention, the mass ratio of the core to the shell is not particularly limited. When the total amount of the multi-layer structure polymer is 100 parts by mass, the core layer accounts for at least 50 parts by mass, By mass or less, more preferably 60 parts by mass or more and 80 parts by mass or less.

Examples of commercially available products of such a multi-layered acrylic granular composite include "Metablen" manufactured by Mitsubishi Rayon, "Kanase" manufactured by Kanegafuchi Chemical Industry Co., "Paraloid" manufactured by Kureha Chemical Industry Co., Acrylate "manufactured by Kanto Kasei Kogyo Co., Ltd.," STAPHYLLOID "manufactured by GANTSU KASEI KOGYO CO., LTD. And" PARAPET SA "manufactured by KURARAY CO., Which may be used singly or in combination.

Specific examples of the acrylic fine particles (c-1) which are graft copolymers suitably used as the acrylic fine particles (C) preferably used in the present invention include unsaturated carboxylic acid ester-based monomers, unsaturated carboxyl- A graft copolymer obtained by copolymerizing a monomer mixture comprising an acid monomer, an aromatic vinyl monomer and, if necessary, another vinyl monomer copolymerizable therewith.

The rubbery polymer used for the acrylic fine particles (c-1) as the graft copolymer is not particularly limited, but diene rubber, acrylic rubber, and ethylene rubber can be used. Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, acrylic acid butyl-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer, Ethylene-methyl acrylate copolymer, methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer and ethylene-methyl acrylate copolymer. These rubbery polymers can be used singly or as a mixture of two or more kinds.

When the refractive index of each of the acrylic resin (A) and the acrylic fine particle (C) is approximate, it is preferable since the transparency of the acrylic resin-containing film of the present invention can be obtained. Specifically, the refractive index difference between the acrylic fine particles (C) and the acrylic resin (A) is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.

In order to satisfy such a refractive index condition, it is necessary to adjust the refractive index difference by a method of adjusting the monomer unit composition ratio of the acrylic resin (A) and / or a method of adjusting the composition ratio of the rubber polymer or monomer used for the acrylic fine particle (C) It is possible to obtain an acrylic resin-containing film excellent in transparency.

Here, the difference in refractive index means that the acrylic resin-containing film of the present invention is sufficiently dissolved in a solvent in which the acrylic resin (A) is soluble to form a whitish solution, which is then subjected to centrifugal separation or the like, (23 deg. C, measurement wavelength: 550 nm) after separating the soluble portion (acrylic resin (A)) and the insoluble portion (acrylic fine particle (C)).

The method of blending the acrylic fine particles (C) in the acrylic resin (A) in the present invention is not particularly limited, and it is preferable to blend the acrylic resin (A) and other optional components in advance, A method of homogeneously melt-kneading with a single-screw or twin-screw extruder while adding the acrylic fine particles (C) is preferably used.

A method in which a solution prepared by previously dispersing the acrylic fine particles (C) is added to a solution (dope) in which the acrylic resin (A) and the cellulose ester resin (B) are dissolved and mixed, or a method in which the acrylic fine particles (C) A method in which a solution prepared by dissolving and mixing an additive of the above-mentioned additives is added in-line.

Commercially available acrylic fine particles (C) of the present invention can also be used. For example, Metablen W-341 (C2) (manufactured by Mitsubishi Rayon Co., Ltd.), Chemisnow MR-2G (C3) and MS-300X .

In the acrylic resin-containing film of the present invention, it is preferable to contain 0.5 to 45 mass% of the acrylic fine particles (C) based on the total mass of the resin constituting the film.

It is preferable that the acrylic fine particles (C) have 40 to 60% of the entire amount of the acrylic fine particles (C) existing in the region within 25% of the entire film thickness from both surfaces of the acrylic resin-containing film. The distribution of the acrylic fine particles (C) is achieved, for example, by a preferable film-forming method of an acrylic resin-containing film described later.

This is because if the amount is less than 40%, the film does not have sufficient slidability, and when the film is wound, the films adhere to each other, making handling difficult. If it is more than 60%, the tensile softening point may decrease or the haze value may rise.

The existence ratio of the acrylic fine particles was determined by photographing the cross section of the acrylic resin-containing film at a magnification of about 10,000 to 50,000 times using a high resolution scanning electron microscope (SEM), analyzing the obtained SEM photograph, Is calculated as the existence ratio.

<Other additives>

In the acrylic resin-containing film of the present invention, in order to improve the fluidity and flexibility of the composition, a plasticizer may be used in combination. Examples of the plasticizer include a phthalate ester, a fatty acid ester, a trimellitate ester, a phosphate ester, a polyester, and an epoxy.

Of these, polyester-based and phthalate ester-based plasticizers are preferably used. The polyester-based plasticizer is superior to the phthalate ester-based plasticizer such as dioctyl phthalate in its non-planarity and extrusion resistance, but has a slightly reduced plasticizing effect and compatibility.

Therefore, these plasticizers may be selected or used in combination depending on the application, so that they can be applied to a wide variety of applications.

The polyester plasticizer is a reaction product of a monovalent to tetravalent carboxylic acid and a monovalent to hexavalent alcohol, but mainly a product obtained by reacting a divalent carboxylic acid with a glycol is used. Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid, and the like.

Particularly, when adipic acid, phthalic acid or the like is used, excellent plasticizability is obtained. Examples of glycols include glycols such as ethylene, propylene, 1,3-butylene, 1,4-butylene, 1,6-hexamethylene, neopentylene, diethylene, triethylene and dipropylene. These dicarboxylic acids and glycols may be used singly or in combination.

The ester-based plasticizer may be any of esters, oligoesters, and polyesters. The molecular weight is preferably in the range of 100 to 10000, but preferably in the range of 600 to 3000, the plasticizing effect is large.

The viscosity of the plasticizer is related to the molecular structure and the molecular weight, but in the case of the adipic acid-based plasticizer, the range of 200-5000 mPa ((25 캜) is preferable from the viewpoint of compatibility and plasticization efficiency. In addition, several polyester plasticizers may be used in combination.

The plasticizer is preferably added in an amount of 0.5 to 30 parts by mass based on 100 parts by mass of the composition containing the acrylic resin (A). When the addition amount of the plasticizer exceeds 30 parts by mass, the surface is sticky, which is not preferable for practical use.

The composition containing the acrylic resin (A) of the present invention preferably contains an ultraviolet absorber. Examples of the ultraviolet absorber to be used include benzotriazole-based, 2-hydroxybenzophenone-based or salicylic acid phenylester- have. For example, there can be mentioned 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5- , Triazole compounds such as 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- Phenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

Among the ultraviolet absorbers, the ultraviolet absorber having a molecular weight of 400 or more is difficult to volatilize at a high boiling point and is hardly scattered even at high temperature molding, so that the addition of a relatively small amount can effectively improve the weatherability.

In addition, it is particularly preferable that the transition from a thin coating layer to a substrate layer is small and it is difficult to deposit on the surface of the laminate, and therefore the amount of the ultraviolet absorber contained therein is maintained for a long time and the sustainability of the weathering improving effect is excellent.

Examples of the ultraviolet absorber having a molecular weight of not less than 400 include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- (2,2,6,6-tetramethyl-4-piperidyl) benzophenone-based compound such as bis (2,2,6,6-tetramethyl- Sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and furthermore 2- (3,5-di-t-butyl- 1- [2- [3- (3,5-di-t-butoxycarbonyl) -2-n-butylmalonic acid bis (1,2,2,6,6- Propyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6- Tetramethylpiperidine, and the like. These compounds may be used either singly or in combination of two or more. The term &quot; hindered amine &quot; Among these compounds, preferred are 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- -Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

In addition, various kinds of antioxidants may be added to the acrylic resin (A) used in the acrylic resin-containing film of the present invention in order to improve the thermal decomposition property and thermal coloring property during molding. It is also possible to add an antistatic agent to impart an antistatic property to the acrylic resin-containing film.

As the acrylic resin composition of the present invention, a flame retardant acrylic resin composition containing a phosphorus flame retardant may be used.

Examples of the phosphorus-based flame retardant used herein include triaryl phosphoric acid esters, diaryl phosphoric acid esters, monoaryl phosphoric acid esters, arylphosphonic acid compounds, arylphosphine oxide compounds, condensed aryl phosphoric acid esters, halogenated alkyl phosphoric acid esters, halogen-containing condensed phosphoric acid esters , A halogen-containing condensed phosphonic acid ester, a halogen-containing phosphorous acid ester, and the like, or a mixture of two or more thereof.

Specific examples thereof include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl) Tris (tribromoneopentyl) phosphate, and the like.

<Formation of film containing acrylic resin>

An example of a film-forming method of an acrylic resin-containing film will be described, but the present invention is not limited thereto.

As the film forming method of the acrylic resin-containing film of the present invention, a manufacturing method such as an inflation method, a T-die method, a calendering method, a cutting method, a fining method, an emulsion method and a hot press method can be used. , Suppression of optical defects such as die lines, and the like are preferable.

(Organic solvent)

The organic solvent useful for forming the dope when the acrylic resin-containing film of the present invention is produced by the solution casting method can be used without limitation as long as it can simultaneously dissolve the acrylic resin (A), the cellulose ester resin (B) have.

Examples of the chlorinated organic solvent include methylene chloride and examples of the non-chlorinated organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, , Ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3 , 3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro Propanol, nitroethane and the like, and methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

The dope preferably contains, in addition to the organic solvent, a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in an amount of 1 to 40 mass%. When the proportion of alcohol in the dope is high, the web is gelled, and the separation from the metal support is facilitated. When the proportion of the alcohol is low, dissolution of the acrylic resin (A) and the cellulose ester resin (B) in the non- As well.

Particularly, three kinds of acrylic resin (A), cellulose ester resin (B) and acrylic fine particles (C) are dissolved in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, By weight to 45% by weight of the dope composition.

Examples of the straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Ethanol is preferred from the viewpoints of stability and boiling of these internal dope, relatively good drying property, and the like.

Hereinafter, a preferable film-forming method of the acrylic resin-containing film of the present invention will be described.

1) Dissolution Process

(A), a cellulose ester resin (B) and, if necessary, an acrylic fine particle (C), an acrylic ester resin (B), and the like, in an organic solvent mainly containing a good solvent for the acrylic resin (A) and the cellulose ester resin (A) and the cellulose ester resin (B) are mixed with the acrylic fine particle (C) solution and other additive solutions as occasion demands to prepare a solution of the main solution To form a dope.

The dissolution of the acrylic resin (A) and the cellulose ester resin (B) can be carried out at a normal pressure, a method of carrying out the polymerization at a boiling point of the main solvent or a method of performing pressurization at a boiling point or more of the main solvent, , A method of performing a cooling dissolution method as described in JP-A-9-95557 or JP-A-9-95538, a method of performing at a high pressure as described in JP-A-11-21379 Although a dissolution method can be used, a method of carrying out by pressurization at a boiling point or more of the main solvent is preferable.

The content of the acrylic resin (A) and the cellulose ester resin (B) in the dope is preferably in the range of 15 to 45% by mass. Additives are added to the dope during or after dissolution, dissolved and dispersed, filtered with a filter, defoamed, and sent to the next process by a liquid-feeding pump.

The filtration is preferably performed using a filter medium having a collection particle diameter of 0.5 to 5 탆 and a filtration time of 10 to 25 sec / 100 ml.

In this method, only the aggregate can be removed by using the aggregate remaining at the time of dispersing the particles or the aggregates generated at the time of adding the main dopes by using a filter medium having a collection particle diameter of 0.5 to 5 占 퐉 and a filtration time of 10 to 25 sec / 100 ml. In the main dope, since the concentration of the particles is sufficiently lower than that of the additive liquid, the aggregates do not stick to each other at the time of filtration, so that the filtration pressure does not rise rapidly.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view schematically showing a dope producing process, a softening process and a drying process of a solution casting film-forming method preferable in the present invention.

If necessary, large aggregates are removed from the acrylic fine particle charging kiln 41 by the filter 44, and the liquid is sent to the storage tank 42. Thereafter, the acrylic fine particle addition liquid is added to the main dope melting furnace (1) from the storage tank (42).

Thereafter, the main dope liquid is filtered by the main filter 3, and the liquid added with the ultraviolet absorbent is added inline to the liquid.

In most cases, the main dope may contain about 10 to 50 mass% of a return material. In some cases, the recycled material may contain acrylic fine particles. In this case, it is preferable to control the addition amount of the acrylic fine particle added liquid in accordance with the addition amount of the semi-finished material.

The additive liquid containing the acrylic fine particles preferably contains 0.5 to 10 mass% of acrylic fine particles, more preferably 1 to 10 mass%, and most preferably 1 to 5 mass%.

The smaller the content of the acrylic fine particles is, the easier it is to handle at a low viscosity, and the more the content of the acrylic fine particles is, the smaller the addition amount and the easier the addition to the main dope.

The term &quot; semi-finished product &quot; means a product obtained by finely pulverizing an acrylic resin-containing film. The semi-finished product is obtained by cutting both side portions of the film, which are generated when a film containing an acrylic resin is formed, do.

It is also preferable to knead an acrylic resin, a cellulose ester resin and, if necessary, acrylic fine particles in advance to pelletize them.

2) Flexible process

An endless metal support 31 for feeding the dope to the pressure die 30 through a feed pump (for example, a pressurized metering gear pump) and infinitely feeding it, for example, a stainless steel belt or a rotating metal drum Is a process of softening the dope from the pressure die slit at the flexible position on the metal support.

It is preferable to use a press die which can adjust the slit shape of the die-tearing portion of the die and make the film thickness uniform. The pressure die includes a coat hanger die and a T die, all of which are preferably used. The surface of the metal support is mirror-finished. Two or more pressure dies may be provided on the metal support in order to increase the film forming speed, and the doping amount may be divided into two or more layers. Alternatively, it is also preferable to obtain a laminated film by a covalent bonding method in which a plurality of doughs are simultaneously flexible.

3) Solvent evaporation process

A web (a dope film formed by softly dope a flexible support on a support) is heated on a flexible support to evaporate the solvent.

In order to evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back surface of the support by liquid, and a method of transferring heat from the front and rear sides by radiant heat. . Also, a method of combining them is also preferably used.

It is preferable to dry the web on the supporter after the softening on the support in an atmosphere of 40 to 100 캜. In order to maintain the temperature at 40 to 100 占 폚, it is preferable to apply warm air at this temperature to the upper surface of the web or heat it by means of infrared rays or the like.

From the standpoint of surface quality, moisture permeability and releasability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process

And peeling the web from which the solvent has evaporated on the metal support at the peeling position. The stripped web is sent to the next process.

The temperature at the peeling position on the metal support is preferably 10 to 40 占 폚, more preferably 11 to 30 占 폚.

The amount of the residual solvent at the time of peeling the web on the metal support at the time of peeling is desirably peeled in the range of 50 to 120 mass% depending on the strength of the drying condition, the length of the metal support, etc. However, When the web is peeled off at many points of time, if the web is excessively soft, the flatness is deteriorated when peeling off, or the peeling tension or vertical stripes tend to occur, so that the amount of residual solvent at the time of peeling is determined in balance of economic speed and quality.

The amount of residual solvent in the web is defined by the following equation.

Residual solvent amount (%) = (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) 占 100

The heat treatment for measuring the amount of the residual solvent means that the heat treatment is performed at 115 占 폚 for 1 hour.

The peel tension when peeling the film from the metal support is usually 196 to 245 N / m, but it is preferable to peel off with a tensile force of 190 N / m or less when wrinkles tend to enter at peeling, To 166.6 N / m, and subsequently to the lowest tension to 137.2 N / m, particularly preferably to the lowest tension to 100 N / m.

In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 占 폚, more preferably 10 to 40 占 폚, and most preferably 15 to 30 占 폚.

5) Drying and drawing process

After peeling, the web is dried by using a drying device 35 for conveying the web alternately in a plurality of rolls arranged in the drying apparatus and carrying it, and / or a tenter stretching device 34 for clipping and conveying both ends of the web with clips .

The drying means generally blows hot air on both sides of the web, but there is also a means for heating by applying a microwave instead of the wind. Too rapid drying tends to impair the planarity of the finished film. The drying at a high temperature is preferably carried out at a residual solvent of about 8% by mass or less. Throughout, the drying takes place at approximately 40 to 250 ° C. Particularly preferably 40 to 160 캜.

When a tenter stretching device is used, it is preferable to use a device capable of independently controlling the gripping length of the film (the distance from the start of gripping to the end of gripping) by the left and right gripping means of the tenter. Further, in the tentering process, it is also desirable to make a compartment having a temperature that is intentionally different in order to improve planarity.

It is also preferable to provide a neutral zone so that the respective compartments do not cause interference between different temperature zones.

Further, the stretching operation may be divided into multiple steps, or biaxial stretching in the machine direction and the width direction is preferably performed. In the case of biaxial stretching, simultaneous biaxial stretching may be performed, or may be performed stepwise.

In this case, the term "stepwise" means that, for example, the stretching in different stretching directions can be sequentially performed, the stretching in the same direction can be divided into multiple steps, and the stretching in different directions can be added at any stage. That is, for example, the following stretching step is also possible.

- Stretching in the flexible direction - Stretching in the width direction - Stretching in the flexible direction - Stretching in the flexible direction

- stretching in the width direction - stretching in the width direction - stretching in the softening direction - stretching in the softening direction

Also, simultaneous biaxial stretching may include stretching in one direction and shrinking the other by relaxing the tension. The stretching magnification which is preferred for simultaneous biaxial stretching can be taken in the range of 占 1.01 times to 占 1.5 times in both the width direction and the longitudinal direction.

The amount of the residual solvent in the web in the case of conducting the tenter stretching is preferably 20 to 100 mass% at the start of the tenter, and it is preferable to carry out drying while adding the tenter until the amount of the residual solvent in the web becomes 10 mass% By mass, and more preferably 5% by mass or less.

The drying temperature in the case of conducting the tenter stretching is preferably 30 to 150 占 폚, more preferably 50 to 120 占 폚, and most preferably 70 to 100 占 폚.

In the tenter stretching process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of enhancing the uniformity of the film. The temperature distribution in the width direction in the tenter stretching process is preferably within ± 5 ° C, And most preferably within ± 1 ° C.

6) Winding process

When the amount of the residual solvent in the web becomes 2% by mass or less, the film is taken up by the winder 37 as an acrylic resin-containing film. When the residual solvent amount is 0.4% by mass or less, a film having good dimensional stability can be obtained.

As the winding method, a generally used one may be used, such as a static torque method, a constant tension method, a taper tension method, and a program tension control method with a constant internal stress, and they may be used separately.

The acrylic resin-containing film of the present invention is preferably a long film, specifically about 100 m to 5000 m, and is usually provided in a roll shape. Further, the width of the film is preferably 1.3 to 4 m, more preferably 1.4 to 3 m.

The film thickness of the acrylic resin-containing film of the present invention is not particularly limited, but it is preferably 20 to 200 占 퐉, more preferably 25 to 100 占 퐉, more preferably 30 to 80 占 퐉 Is particularly preferable.

<Polarizer>

The polarizing plate used in the present invention can be produced by a general method. It is preferable that an adhesive layer is formed on the back side of the acrylic resin-containing film of the present invention and is bonded to at least one surface of a polarizer produced by immersion stretching in an iodine solution.

Other film may be used for the other side, or another polarizing plate protective film may be used. For example, commercially available cellulose ester films (for example, Konica Minolta Tact KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KV8UY-HA, KV8UX- Konica Minolta Opto Co., Ltd.) and the like are preferably used.

The polarizer, which is a main component of the polarizer, is a device which allows only light of a polarization plane in a certain direction to pass. A currently known polarizer film is a polyvinyl alcohol polarizer film, which is obtained by dyeing a polyvinyl alcohol film with iodine And dyed dichromatic dyes.

Polarizers are prepared by forming a polyvinyl alcohol aqueous solution, uniaxially stretching it, dyeing it, uniaxially stretching it, and preferably durability treatment with a boron compound.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, it is preferable that at least a part of the pressure-sensitive adhesive layer has a pressure-sensitive adhesive having a storage elastic modulus at 25 ° C in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁹ Pa, A curing type pressure-sensitive adhesive which forms a high molecular weight or crosslinked structure by various chemical reactions after bonding is appropriately used.

Specific examples thereof include curable pressure sensitive adhesives such as urethane pressure sensitive adhesives, epoxy pressure sensitive adhesives, water based polymer-isocyanate pressure sensitive adhesives, thermosetting acrylic pressure sensitive adhesives, moisture cured urethane pressure sensitive adhesives, polyether methacrylate type, ester methacrylate type, An anaerobic tackifier such as polyether methacrylate, a cyanoacrylate type instantaneous tackifier, and an acrylate and a peroxide type two-component type instant tackifier.

The pressure-sensitive adhesive may be a one-component type, or two or more liquids may be mixed before use.

The pressure-sensitive adhesive may be a solvent based on an organic solvent, or may be a water-based medium such as an emulsion type, a colloidal dispersion type or an aqueous solution type, which is a medium containing water as a main component. The concentration of the pressure-sensitive adhesive liquid may be appropriately determined depending on the thickness of the pressure-sensitive adhesive film, the application method, the application conditions, and the like, and is usually 0.1 to 50 mass%.

<Liquid Crystal Display Device>

By incorporating the polarizing plate bonded with the acrylic resin-containing film of the present invention into a liquid crystal display device, a liquid crystal display device excellent in various visibility can be manufactured. The polarizing plate according to the present invention is bonded to the liquid crystal cell through the adhesive layer or the like.

The polarizing plate according to the present invention is preferably used as an LCD of various driving methods such as a reflective type, a transmissive type, a semi-transmissive type LCD or a TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type) do. Particularly, in the case of a display device having a screen of 30 or more in size, particularly 30 to 54 in a large screen, there is no pinhole at the periphery of the screen, and the effect is maintained for a long time.

In addition, there is an effect that the color irregularity, the glare and the wavy irregularity are small, and the eyes are not tired even for a long time of appreciation.

Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

Example 1

&Lt; Production of acrylic resin-containing film &

(Production of acrylic resin-containing film 1)

(Preparation of dope liquid)

BR85 (acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.) 70 parts by mass

Cellulose ester (cellulose acetate propionate, acetyl group total degree of substitution 2.75, acetyl group degree of substitution 0.19, propionyl group degree of substitution 2.56, Mw = 200000)

30 parts by mass

2 parts by mass of the acrylic fine particles (C1)

300 parts by mass of methylene chloride

40 parts by mass of ethanol

&Lt; Production of acrylic fine particles (C1) &gt;

38.2 liters of ion-exchanged water and 111.6 g of sodium dioctylsulfosuccinate were charged into a reactor having a reflux condenser having an internal volume of 60 liters and the temperature was raised to 75 DEG C under nitrogen atmosphere with stirring at a rotation speed of 250 rpm, I was in a state that was virtually absent. After stirring for 5 minutes, a monomer mixture consisting of 1657 g of MMA, 21.6 g of BA and 1.68 g of ALMA was added in a lump and the polymerization was continued for 20 minutes after the exothermic peak was detected to polymerize the innermost hard layer It was completed.

Then, 3.48 g of APS was added, and after stirring for 5 minutes, a monomer mixture composed of 8105 g of BA, 31.9 g of PEGDA (200) and 264.0 g of ALMA was continuously added over 120 minutes, and after the addition was completed, , The polymerization of the soft layer was completed.

Then, 1.32 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 2106 g of MMA and 201.6 g of BA was continuously added over a period of 20 minutes. After completion of the addition, the polymerization was continued for 20 minutes to complete the polymerization of the outermost hard layer did.

Subsequently, 1.32 g of APS was added, and after 5 minutes, a monomer mixture consisting of 3148 g of MMA, 201.6 g of BA and 10.1 g of n-OM was continuously added over 20 minutes, and the addition was continued for 20 minutes after completion of the addition. Subsequently, the temperature was raised to 95 캜 and maintained for 60 minutes to complete the polymerization of the outermost hard layer 2.

A small amount of the polymer latex thus obtained was sampled, and the average particle diameter was determined by the absorbance method. The result was 0.10 탆. The remaining latex was added to a 3 mass% sodium sulfate aqueous solution to be subjected to salting out and solidification, followed by dehydration and washing repeatedly, followed by drying to obtain acrylic fine particles (C1) having a three-layer structure.

The above abbreviations are respectively the following materials.

MMA: methyl methacrylate

MA: methyl acrylate

BA: n-butyl acrylate

ALMA: Allyl methacrylate

PEGDA: polyethylene glycol diacrylate (molecular weight 200)

n-OM: n-octylmercaptan

APS: Ammonium persulfate

(Film formation of acrylic resin-containing film)

The dope liquid prepared above was uniformly plied to a stainless steel band support at a temperature of 22 캜 and a width of 2 m by using a belt softener. In the stainless steel band support, the solvent was evaporated until the amount of the residual solvent became 100%, and peeled off from the stainless steel band support with a peel tension of 162 N / m. The web of the peeled acrylic resin was evaporated at 35 DEG C to evaporate the solvent, and the film was slit with a width of 1.6 m. Thereafter, the web was dried at a drying temperature of 135 DEG C while being stretched 1.1 times in the width direction by a tenter. At this time, the amount of the residual solvent when the stretching was started by the tenter was 10%. After the stretching by a tenter, the film was relaxed at 130 캜 for 5 minutes, and the drying zone was then conveyed while the drying zone at 120 캜 and 130 캜 was conveyed by a plurality of rolls. The film was slit at a width of 1.5 m, Mu] m and was wound around a 6-inch inner core at an initial tension of 220 N / m and a final tension of 110 N / m to obtain an acrylic resin-containing film 1. The draw ratio in the MD direction calculated from the rotation speed of the stainless steel band support and the operation speed of the tenter was 1.10 times and the TD direction was 1.01 times. The residual solvent amount of the acrylic resin-containing film 1 shown in Tables 2 and 3 was 0.1%, the film thickness was 60 μm, and the number of windings was 5000 m.

The amount, type and composition ratio of the acrylic resin (A), the cellulose ester resin (B) and the acrylic fine particles (C) were changed as shown in Tables 2 and 3, Films 2-34 were prepared.

The acrylic resins used in the acrylic resin-containing films 1 to 28 and 33 and 34 were Delpet 80N (manufactured by Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85 and BR88 (manufactured by Mitsubishi Rayon Co., Ltd.) Respectively.

The acrylic resins A1 to A4 used in the acrylic resin-containing films 29 to 32 were produced by a known method.

A1: poly (MMA-MA) mass ratio 98: 2 Mw70000

A2: poly (MMA-MA) mass ratio 97: 3 Mw 800000

A3: poly (MMA-MA) mass ratio 97: 3 Mw930000

A4: poly (MMA-MA) mass ratio 94: 6 Mw1100000

MMA: methyl methacrylate

MA: methyl acrylate

In addition, the abbreviations of the columns of degrees of substitution of the cellulose ester resin (B) shown in Tables 2 and 3 are as follows:

ac: acetyl group

p: propionyl group

b: Butyryl group

bz: benzoyl

oc: octanoyl group

ph: phthalyl group

Further, the acrylic resin-containing films 6 and 11 were prepared by adding the ultraviolet absorbent described below.

Acrylic resin-containing film 6

1.5 parts by mass of Tinuvin 109 (manufactured by Shiba Japan K.K.)

0.7 parts by mass of Tinuvin 171 (manufactured by Shiba Japan K.K.)

Acrylic resin-containing film 11

1.5 parts by mass of LA-31 (manufactured by ADEKA)

Further, the comparative cellulose triacetate films 1 to 3 were produced in the following manner.

(Preparation of Comparative Cellulose Triacetate Film 1)

100 parts by mass of cellulose triacetate (degree of acetatization: 61%), 12 parts by mass of TPP (triphenyl phosphate), 320 parts by mass of methylene chloride, 50 parts by mass of methanol and 10 parts by mass of 1-butanol were put into a dope mixing tank, By stirring, cellulose triacetate was dissolved to prepare a dope. Separately, 15 parts by mass of ultraviolet absorber UV-1, 80 parts by mass of methylene chloride and 20 parts by mass of methanol were charged into another mixing tank and heated and stirred to dissolve the ultraviolet absorber. And 0.5 parts by mass of fine particles of silicon dioxide (trade name: Aerosil R972D, primary particle average particle diameter: 0.016 占 퐉; manufactured by Nippon Aerosil Co., Ltd.) were charged and transferred to a disperser, And dispersed so as to have an average particle diameter of 0.3 mu m to prepare a dispersion, which was used as a solution containing ultraviolet absorber. The ultraviolet absorber-containing solution was added to 100 parts by mass of the prepared dope at a ratio of 2 parts by mass, sufficiently mixed in a mixing tank, and then poured into a flexible band as a 50 ° C dope. The softening was carried out so that the thickness of the dried film became 80 mu m. After drying from the flexible band, peeling off, and drying at 145 캜 for 15 minutes in a drying zone, a comparative cellulose triacetate film 1 (indicated as Comparative Example 1 in Table 5) having a thickness of 80 탆 was produced.

(Preparation of Comparative Cellulose Triacetate Film 2)

, 3.3 mass% of cellulose triacetate (average degree of acetatization: 61%), 88 mass% of methylene chloride, 8 mass% of methanol (average particle diameter: 0.5 m, primary particle size of 16 nm) %. Next, a dope of a mixed composition of 17% by mass of cellulose triacetate (average degree of acetalization of 61%), 2% by mass of plasticizer, 71% by mass of methylene chloride, 6% by mass of methanol and 4% by mass of the mat agent solution was prepared in advance. The dope was swelled and then cooled to -70 占 폚. Further, the dope was introduced into the autoclave substituted in a nitrogen atmosphere and dissolved at 160 DEG C and 0.98 MPa for 10 minutes. The solution was filtered and then poured onto a flexible band as a 50 DEG C dope. The softening was carried out so that the thickness of the dried film became 80 mu m. After drying from the flexible band, peeling off, and drying in a drying zone at 145 캜 for 15 minutes, 80 탆 -thickness comparative cellulose triacetate film 2 (shown as Comparative Example 2 in Table 5) was obtained. The content of the mat agent in the obtained film was 0.15% by mass.

(Preparation of Comparative Cellulose Triacetate Film 3)

The dope liquid of cellulose triacetate was prepared as follows.

Cellulose triacetate (TAC): 100 kg

Tinuvin 326 (manufactured by Shiba Japan): 0.3 kg

Tinuvin 171 (manufactured by Shiba Japan): 0.5 kg

Tinuvin 109 (manufactured by Shiba Japan): 0.5 kg

Ethyl phthalyl ethyl glycolate: 2 kg

Triphenylphosphate (TPP): 9.7 kg

Aerosil 200 V (manufactured by Nippon Aerosil Co., Ltd.): 0.09 kg

Methylene chloride: 320 kg

Ethanol: 20kg

These were put into a sealed container and completely dissolved therein while heating and stirring under pressure at 80 캜.

After the dope solution was filtered, the dope was immersed in a flexible band at 33 캜. The softening was carried out so that the thickness of the dried film became 80 mu m. After drying from the flexible band, peeling off, and drying at 145 캜 for 15 minutes in a drying zone, a comparative cellulose triacetate film 3 (indicated as Comparative Example 3 in Table 5) having a thickness of 80 탆 was obtained.

"Assessment Methods"

The obtained acrylic resin-containing films 1 to 34 and comparative cellulose triacetate films 1 to 3 were subjected to the following evaluations, and the results are shown in Tables 4 and 5.

(Calculation of abundance of particles)

Sectional SEM images of the acrylic resin-containing films 1 to 33, the comparative cellulose triacetate films 1 to 3 and the comparative acrylic resin-containing film 34 were analyzed to calculate the presence ratio of the acrylic fine particles and silicon dioxide in the film thickness direction.

(Hayes)

Each film sample thus prepared was subjected to a humidity control in an air conditioner at 23 DEG C and 55% RH for 24 hours, and one film sample was measured under the above conditions in accordance with JIS K-7136 using a haze meter (NDH2000 type, manufactured by Nippon Denshoku Kogyo Co., Ltd.).

(Tension softening point)

The following evaluations were carried out using a tensilon tester (RTC-1225A, manufactured by ORIENTEC).

The acrylic resin-containing film, which was humidified for 24 hours in an air conditioner at 23 ° C and 55% RH for 24 hours, was cut at 120 mm (length) × 10 mm (width) under the above conditions and pulled at a tensile force of 10 N The temperature was kept at a constant temperature, and the temperature at the time when the temperature reached 9 N was measured three times, and the average thereof was obtained.

(Ductile fracture)

The acrylic resin-containing film, which was conditioned in an air conditioner at 23 ° C and 55% RH for 24 hours, was cut into 100 mm (length) × 10 mm (width) under the above conditions and a curvature radius of 0 mm and a bending angle of 180 ° The films were folded one at a time by two folds with a folding line and a folding line so that the films would overlap perfectly. The evaluation was measured three times and evaluated as follows. In addition, the term "cracking" as used herein means that cracks are separated into two or more pieces.

○ ... It does not break all three times.

× ... At least one of three breaks.

(Coefficient of static friction)

Each of the thus-prepared film samples was subjected to humidity control in an air conditioner at 23 캜 and 55% RH for 24 hours, and then measured using a friction measuring instrument TR-2 (manufactured by Toyo Seiki Co., Ltd.).

(Film strain)

Each film sample thus prepared was allowed to stand in an atmosphere of 90 DEG C and DRY (relative humidity of 5% RH or less) for 1000 hours, and the degree of film distortion was visually observed under conditions of 23 DEG C and 55% RH.

?: No deformation of the film at all.

DELTA: Deformation of the film is confirmed.

X: Distortion of the film was confirmed.

(Cutting property)

The film was touched with a light tear tear (Elmendorf) tester (manufactured by Toyo Seiki Co., Ltd.) under the above conditions and subjected to a humidity control in an air conditioner at 23 占 폚 and 55% RH for 24 hours.

○: The opening surface is very smooth and torn straight.

B: There is a slight burr on the open side of the phosphorus, but it is torn straight.

X: There is considerable burr on the open side of the phosphorus, and it is not torn straight.

(Film appearance)

With respect to the produced film, the appearance of the film which was humidified for 24 hours in an air conditioner at 23 ° C and 55% RH was visually evaluated and evaluated as follows.

?: Very smooth planarity.

?: A little drag, wrinkle, and level difference can be confirmed.

X: It is possible to confirm the drawing, the wrinkle, the step difference surely.

(Production of polarizing plate)

A long roll polyvinyl alcohol film having a thickness of 120 占 퐉 was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid and stretched 5 times at 50 占 폚 in the carrying direction to form a polarizing film. Next, the acrylic resin-containing film 1 prepared in Example 1 was subjected to corona treatment using an acrylic adhesive on one side of the polarizing film, and then bonded. Further, KC4UY made by Konica Minolta Opto, which is an alkali saponified phase difference film, was bonded to the other side of the polarizing film and dried to produce a polarizing plate P1. Similarly, polarizing plates P2 to P37 (corresponding film numbers are shown in Tables 4 and 5, respectively) were produced using acrylic resin-containing films 2 to 34 and comparative cellulose triacetate films 1 to 3. The polarizing plate using the acrylic resin-containing film of the present invention was excellent in film cutting property and easy to process.

(Characteristic Evaluation as a Liquid Crystal Display)

&Lt; Production of liquid crystal display device &

The polarizing plate on the viewing side which had been bonded in advance was peeled off by using a liquid crystal television Wooo32 H-90 made by Hitachi, which is an IPS mode liquid crystal display, and the polarizing plates P1 to P37 were laminated on the acrylic resin- So as to be a glass surface. At that time, the polarizing plate was joined so that the absorption axis was directed in the same direction as the previously polarized polarizing plate. Thus, the liquid crystal display devices 1 to 37 were manufactured.

(Variation in viewing angle)

The following evaluations were carried out using the liquid crystal display devices 1 to 37 manufactured as described above.

The viewing angle of the liquid crystal display device was measured using an EZ-Contrast 160D manufactured by ELDIM under the environment of 23 占 폚 and 55% RH. Subsequently, the polarizing plate treated at 60 DEG C and 90% RH for 1000 hours was similarly measured, and evaluated in four stages based on the following criteria.

?: No change in viewing angle.

?: Variation in viewing angle is confirmed.

X: Variation in viewing angle is very large.

(Color shift)

A polarizing plate was attached in the same manner as in the evaluation of viewing angle of the base material to produce liquid crystal display devices 1 to 37. Next, the display was evaluated as a black display, and the change in color when observed from an angle of 45 DEG with respect to the front was evaluated as the following criteria.

?: No color change.

?: Color change is confirmed.

X: The color change is very large.

The results of the above evaluation are shown in Tables 4 and 5.

From Table 4 and Table 5, it can be seen that the acrylic resin-containing film of the present invention has excellent transparency, high heat resistance and remarkably improved brittleness. By using the acrylic resin-containing film, It is possible to improve the yield in the operation of the liquid crystal display device and also the length of the film winding can be made longer and work efficiency can be increased. Further, when used in a liquid crystal display device, the color shift that occurs depending on the viewing angle is reduced, The liquid crystal display device can be obtained.

1: melting pot
3, 6, 12, 15: filter
4, 13: Storage tank
5, 14: Pump pump
8, 16: conduit
10: Ultraviolet absorber input kiln
20: junction pipe
21: Mixer
30: Die
31: metal support
32: Web
33: Peeling position
34: Tenter stretching device
35: Roll dryer
41: particulate input kiln
42: Storage tank
43: pump
44: Filter

Claims (7)

A film comprising an acrylic resin-containing film containing 10 to 50 parts by mass of a cellulose ester resin (B) relative to 50 to 90 parts by mass of the acrylic resin (A), wherein one side of the acrylic resin- Wherein the polyester resin has a static friction coefficient of 0.3 to 0.8, a tensile softening point of 105 to 145 占 폚, a haze value of less than 1%, and does not cause ductile fracture. The acrylic resin-containing film according to claim 1, wherein the acrylic resin (A) of the acrylic resin-containing film has a weight average molecular weight (Mw) of 80000 to 1000000 and a total substitution degree (T) of the acyl group of the cellulose ester resin , The acetyl group substitution degree (ac) is 0.10 to 1.90, the part other than the acetyl group is substituted with an acyl group having 3 to 7 carbon atoms, the degree of substitution (r) is 1.10 to 2.90, (Mw) of 75000 to 280000 and the film contains the acrylic fine particles (C) in an amount of 0.05 to 45% by mass relative to the total mass of the film, and the acrylic fine particles have a thickness of 25% Of the total amount of the acrylic resin-containing film is present in an area within 40 to 60% of the total amount of the acrylic resin-containing film. A process for producing an acrylic resin-containing film, wherein the acrylic resin-containing film according to claim 1 or 2 is produced by stretching 5% to 40% in at least one direction. A polarizing plate characterized by using the acrylic resin-containing film according to any one of claims 1 to 3. A liquid crystal display device using the polarizing plate according to claim 4. A polarizing plate characterized by using the film produced by the method for producing an acrylic resin-containing film according to claim 3. A liquid crystal display device characterized by using the polarizing plate according to claim 6.

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