KR101498397B1 - Resin film, method for producing resin film, polarizing plate, and liquid crystal display - Google Patents

Abstract

The present invention provides a resin film which is excellent in moisture resistance and heat resistance, and can sufficiently suppress the occurrence of problems that may occur during elongation such as dislocation of silica particles and uneven orientation. This resin film is characterized by containing at least one member selected from the group consisting of an acrylic resin, silica particles, a silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensation product of the hydrolyzate.

Description

TECHNICAL FIELD [0001] The present invention relates to a resin film, a method of manufacturing a resin film, a polarizing plate, and a liquid crystal display device,

The present invention relates to a resin film, a method for producing a resin film, a polarizing plate using the resin film as a transparent protective film, and a liquid crystal display device provided with the polarizing plate.

BACKGROUND ART Resin films have been used in various fields, such as optical films, for liquid crystal display devices and the like, in view of their chemical, mechanical and electrical properties. Specifically, in the image display area of the liquid crystal display device, various resin films, for example, a transparent protective film for protecting the polarizing elements of the polarizing plate, and the like are disposed. A resin film excellent in transparency is used as the resin film used as an optical film in such a liquid crystal display device. Such a resin film can be produced by using a resin solution (dope) in which a transparent resin as a raw material resin is dissolved in a solvent. Specific examples of the method for producing the resin film using such a dope include a solution casting film forming method and the like. The solution casting film forming method is a method in which a dope is formed on a support to be run to form a flexible film and dried to the extent that it can be peeled off and then peeled from the support as a film, And the like, thereby producing a resin film having a long shape.

In addition, a resin film used as an optical film in a liquid crystal display device is generally long and is provided as a film roll rolled up on a winding core for storage and transportation. When the resin film is used, the resin film is sequentially released from the film roll.

Such a roll-wound resin film is sometimes subjected to a so-called blocking phenomenon in which the resin films are pressed and adhered to each other by a load caused by a resin film or a winding core. As described above, when the resin films are adhered to each other, there is a problem that the surface of the portion to which the resin film is adhered is roughened when the resin film is unwound from the film roll. For example, when such a resin film is used as a polarizing plate protective film, image unevenness occurs due to the harmonized portion. Further, in the case of using a resin film, it is required that the length of the resin film wound on the winding core, the so-called winding length is long, in order to reduce the replacement frequency of the film roll and improve the working efficiency have. When such a long-shaped resin film is wound in the form of a roll, the load caused by the resin film or the winding core becomes larger, and the occurrence of blocking tends to become remarkable. For this reason, it is known that the resin film used as the optical film in the liquid crystal display device contains fine particles such as silica particles as an anti-blocking agent to suppress the occurrence of blocking, thereby increasing the slipperiness of the resin film.

As the resin film containing such fine particles, for example, those described in Patent Document 1 can be mentioned. Patent Document 1 describes a cellulose ester containing 0.04 to 0.3 mass% of fine particles in the cellulose ester based on the cellulose ester.

Examples of the anti-blocking agent include those described in Patent Document 2. Patent Document 2 discloses an anti-blocking agent comprising a surface-treated inorganic particle formed by coating the surface of an inorganic particle selected from silica, zeolite, alumina or iron oxide with an organopolysiloxane.

In addition, the liquid crystal display device is diversified in use fields, and the number of cases where the liquid crystal display device is used outdoors is not limited to indoor use. Specifically, for example, by displaying images or information on a liquid crystal display device, it is possible to provide a large display device that functions as a advertising medium instead of a poster or the like, that is, as a digital signage device, And the like. In such a case, the liquid crystal display device may be used in, for example, high temperature and high humidity, and the deterioration due to moisture absorption of the resin film provided in the liquid crystal display device may become a problem in some cases. Therefore, the resin film to be used is required to have a high moisture resistance capable of suppressing deterioration due to moisture absorption.

On the other hand, an acrylic resin such as polymethyl methacrylate resin (PMMA), which is known as an optical material with low hygroscopicity, is low in hygroscopicity and excellent in heat resistance, transparency, dimensional stability, etc., have. However, the resin film containing an acrylic resin has a property that it is fragile and vulnerable to other resin films used as optical films, for example, cellulose ester film and the like. For this reason, it is difficult to handle, and it is difficult to stably produce an optical film for a liquid crystal display, in particular, a large screen. Concretely, when the end portion of the film is cut, a problem such as breakage may occur.

As the resin film containing such an acrylic resin, for example, those described in Patent Document 3 can be mentioned. Patent Document 3 discloses an acrylic resin composition comprising 50 to 70 parts by weight of methyl methacrylate, 10 to 20 parts by weight of maleic anhydride and 20 to 35 parts by weight of styrene, and a toughness improving agent, wherein the acrylic resin / Is in the range of 60 to 90/40 to 10.

Japanese Patent Application Laid-Open No. 2002-194106 Japanese Patent Application Laid-Open No. 2002-173580 Japanese Unexamined Patent Application Publication No. 5-119217

According to Patent Document 1, it is disclosed that a cellulose ester film excellent in handleability can be obtained. From this, even if the cellulose ester film described in Patent Document 1 is excellent in handleability as a cellulose ester film, the resin constituting the cellulose ester resin is not an acrylic resin in order to improve moisture resistance. Therefore, the handling property of a resin film containing an acrylic resin is not improved.

In addition, a liquid crystal display device, particularly a liquid crystal display device used as a television receiver, is required to have a large-screen and high-picture quality. For this reason, a resin film provided in a liquid crystal display device, for example, a polarizing plate protective film or the like is required not only for improving visibility but also for widening to cope with a larger screen. In order to satisfy this requirement, for example, it is conceivable to conduct stretching, particularly stretching in the direction perpendicular to the longitudinal direction of the resin film, to the resin film.

In order to satisfy the above-mentioned demand, when the silica particles are contained as the anti-blocking agent, there is a possibility that the silica particles are pulled out by stretching in the resin film described in Patent Document 1. [

According to Patent Document 2, since the dispersibility and wettability of the inorganic particles with respect to the resin are improved, it has been disclosed that voids such as bubbles are formed during processing, particularly occurrence of foaming, voids, dropout, etc. during film molding is improved have.

However, the anti-blocking agent disclosed in Patent Document 2 only enhances the affinity between the resin, particularly the polyester resin and the particles, by coating with an organopolysiloxane such as methyl hydrogen polysiloxane. Therefore, when the anti-blocking agent described in Patent Document 2 is contained in a resin film containing an acrylic resin, dropping of the anti-blocking agent at the time of stretching can not be sufficiently suppressed. In addition, when a resin film containing an anti-blocking agent is stretched on a resin film containing an acrylic resin, orientation unevenness tends to occur without being uniformly stretched. Therefore, in a resin film containing an acrylic resin, occurrence of problems that may occur during elongation such as dropout of an anti-blocking agent and uneven orientation is not sufficiently suppressed.

Further, according to Patent Document 3, by including a toughness improver such as an impact-resistant acrylic rubber-methyl methacrylate graft copolymer or butyl-modified acetylcellulose, it is possible to impart toughness without deteriorating transparency, birefringence, Can be improved.

However, the toughness improving agent described in Patent Document 3 is not sufficient to inhibit blocking, and when the silica particles are contained as the anti-blocking agent, the toughness improver is not sufficient to suppress the drop of the silica particles. Also, it was not possible to suppress orientation irregularity that may occur when a resin film containing silica particles, which is an anti-blocking agent, is stretched on a resin film containing an acrylic resin. Therefore, in the resin film containing an acrylic resin, occurrence of problems such as dropout of silica particles and uneven orientation, which may occur during stretching, can not be sufficiently suppressed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and provides a resin film which is excellent in moisture resistance and heat resistance and can sufficiently suppress the occurrence of problems that may occur during elongation such as dislocation of silica particles and uneven orientation . It is another object of the present invention to provide a method for producing the resin film, a polarizing plate using the resin film as a transparent protective film, and a liquid crystal display device provided with the polarizing plate.

The inventor of the present invention contemplated that the reasons for the dropout of the silica particles and the irregularity of orientation during the stretching are as follows.

First, the inventors of the present invention thought that when a resin film containing silica particles is stretched, the resin constituting the resin film deforms with the stretching, while the silica particles hardly deform. From this, it can be considered that the resin around the silica particles acts in a direction away from the silica particles. In addition, the acrylic resin contained in the resin film is resistant to the force, has a high affinity with the silica particles to maintain the contact state with the silica particles, and a gap is generated between the resin and the silica particles I think. It is considered that the silica particles are separated from the resin film due to the gap.

In addition, it is considered that the gap generated between the resin and the silica particles causes unevenness due to the difference in degree of deformation of the resin. Specifically, the resin present around the silica particles is considered to be more susceptible to deformation than the resin in other parts because the resin is separated and separated from the silica particles by the generation of the gaps. It is considered that the non-uniformity of orientation occurs due to the difference in degree of deformation.

The inventor of the present invention has studied variously by paying attention to the problems occurring at the time of drawing, and found that the above object is achieved by the following invention.

A resin film according to one aspect of the present invention is a resin film comprising at least one member selected from the group consisting of an acrylic resin, silica particles, a silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensation product of the hydrolyzate It is characterized by.

According to such a constitution, it is possible to provide a resin film which is excellent in moisture resistance and heat resistance, and which can sufficiently suppress the occurrence of problems that may occur during elongation such as dropout of silica particles and uneven orientation.

This is considered to be due to the following.

First, it is considered that a resin film excellent in moisture resistance and heat resistance can be obtained by containing an acrylic resin as a resin constituting the resin film.

Also, by containing at least one member selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate (hereinafter may be referred to as an "organic silicon compound"), It is considered that the silicon compound is coated. It is considered that the organosilicon compound coated on the silica particles not only has high affinity with the silica particles but also has high affinity with the acrylic resin.

From this, it is considered that when the resin film is stretched, the silica particles are hardly deformed, but the organosilicon compound coated on the silica particles is deformed following the deformation of the resin. Therefore, it is considered that the presence of the organosilicon compound coated on the silica particles suppresses the occurrence of the gap between the silica particles and the resin.

Further, it is considered that the organosilicon compound also bonds the acrylic resin to each other.

From the above point of view, it is considered that the dropout of silica particles and the occurrence of uneven orientation are suppressed.

In the resin film, it is preferable that the silane coupling agent is a compound represented by the following formula (1).

(In formula 1, Y represents a reactive organic functional group, R ¹ represents an alkyl group, OR ² is an alkoxy group, m represents 1 or 2, n represents 0 or 1, m + n is from 1 to 3 Lt; / RTI >

According to this configuration, occurrence of problems that may occur during stretching can be further suppressed. This is because if the silane coupling agent of the organic silicon compound is the silane coupling agent having the above-mentioned structure, the affinity with the silica particle is higher and the effect of the organosilicon compound which suppresses the generation of the gap between the silica particles and the resin is preferably It can be said that it can be exercised.

In the silane coupling agent, it is preferable that the reactive organic functional group is a functional group containing at least one of an amino group and a phenyl group.

According to this configuration, occurrence of problems that may occur during stretching can be further suppressed. This is because a functional group containing at least one of an amino group and a phenyl group has a higher affinity with an acrylic resin and a silane coupling agent which suppresses the generation of a gap between silica particles and a resin by using a silane coupling agent having the above- The effect of the present invention can be more preferably exhibited.

In the above resin film, it is preferable that the silane coupling agent is a compound represented by the following formula (2).

(Wherein R ³ represents an alkylene group, OR ⁴ represents an alkoxy group, p represents 1 to 5, and q represents 1 to 3)

According to this configuration, occurrence of problems that may occur during stretching can be further suppressed. This is because if the silane coupling agent of the organosilicon compound is a silane coupling agent having the above-mentioned structure, the affinity with the silica particle is higher and the effect of the organosilicon compound suppressing the generation of the gap between the silica particles and the resin is preferably And the like. Further, since the two silicon atoms to which an alkoxy group is attached for enhancing the affinity with the silica particles are connected by a linking group containing a polysulfide bond (S _p ), the affinity with the silica particles is higher, The effect of the organosilicon compound which suppresses the generation of gaps between the silica particles and the resin can be more preferably exhibited.

In addition, in the resin film, it is preferable to further include a cellulose ester resin.

According to such a constitution, it is possible to obtain a resin film excellent in workability because it is excellent in moisture resistance and heat resistance, sufficiently inhibited the occurrence of problems in stretching, is excellent in toughness and the like. The obtained resin film is excellent in workability and, for example, it is possible to suppress the occurrence of cracks in the resin film when the end portion of the resin film is cut. By containing the cellulose ester-based resin, the properties of the cellulose ester-based resin, for example, the phase difference developing ability and the like can be expressed.

In the resin film, it is preferable that the refractive index of at least one member selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate is 1.45 to 1.5.

According to such a constitution, it is possible to obtain a resin film which is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems in stretching, and is more excellent in transparency. This is considered to be due to the approximation of the refractive index of the resin constituting the resin film and the refractive index of the organic silicon compound.

Further, in the resin film, it is preferable to further include acrylic particles.

According to this constitution, it is possible to obtain a resin film excellent in workability because it is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems during drawing, is excellent in toughness and the like. The obtained resin film is excellent in workability and, for example, it is possible to suppress the occurrence of cracks in the resin film when the end portion of the resin film is cut.

Further, it is preferable that the resin film is stretched so as to have an elongation of 10 to 200% as determined by the following formula (1) in at least one direction.

&Quot; (1) "

Elongation (%) = {(length after stretching - length before stretching) / length before stretching} x 100

According to such a constitution, it is possible to obtain a resin film which is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems at the time of stretching, and has a wide width. When such a resin film containing silica particles is stretched at such a high elongation, there is a tendency that problems such as dropout of silica particles and irregular orientation tend to occur. However, in the case of the resin film, occurrence of such a problem is suppressed .

According to another aspect of the present invention, there is provided a method for producing a resin film, the method comprising: a flexible step of forming a flexible film on a support on which a resin solution containing an acrylic resin, silica particles and a silane coupling agent is run, And a stretching step of stretching the peeled film in a direction perpendicular to the transport direction of the film.

According to such a constitution, it is possible to obtain a resin film which is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems at the time of stretching, and has a wide width.

A polarizing plate according to another aspect of the present invention includes a polarizing element and a transparent protective film disposed on at least one surface of the polarizing element, wherein the transparent protective film is the resin film.

According to such a constitution, since the transparent protective film of the polarizing plate is a resin film excellent in moisture resistance and heat resistance and suppressing the occurrence of problems in stretching, it can be preferably used for a large-screen liquid crystal display device A polarizing plate can be obtained. Specifically, even a polarizing plate for a large-screen liquid crystal display device is prevented from being deformed by moisture absorption.

According to another aspect of the present invention, there is provided a liquid crystal display device comprising a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell, and at least one of the two polarizing plates is the polarizing plate .

According to such a constitution, since a polarizing plate having a resin film which is excellent in moisture resistance and heat resistance and in which the occurrence of problems during stretching is suppressed is used, even if the polarizing plate is made into a large- Can be suppressed. Specifically, for example, even in a liquid crystal display device having a large screen, it is possible to suppress the occurrence of deformation of the resin film disposed in the image display area due to moisture absorption.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a resin film which is excellent in moisture resistance and heat resistance, and which can sufficiently suppress the occurrence of problems that may occur during elongation such as dislocation of silica particles and uneven orientation. A manufacturing method of the resin film, a polarizing plate using the resin film as a transparent protective film, and a liquid crystal display device including the polarizing plate are provided.

1 is a schematic view showing an example of a basic configuration of a resin film production apparatus for producing a resin film according to the present embodiment.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

The resin film according to the present embodiment contains at least one member selected from the group consisting of an acrylic resin, silica particles, a silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensate of the hydrolyzate. Such a resin film is excellent in moisture resistance and heat resistance, and can sufficiently suppress the occurrence of problems that may occur during elongation such as dislocation of silica particles and non-uniform orientation. This is thought to be due to the following.

First, it is considered that a resin film excellent in moisture resistance and heat resistance is obtained by containing an acrylic resin as a resin constituting the resin film. Also, by containing at least one member selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate (hereinafter, also referred to as an "organic silicon compound"), It is considered that the silicon compound is coated. It is considered that the organosilicon compound coated on the silica particles not only has high affinity with the silica particles but also has high affinity with the acrylic resin. From this, it is considered that when the resin film is stretched, the silica particles are hardly deformed, but the organic silicon compound coated on the silica particles is deformed following the deformation of the resin. Therefore, it is considered that the presence of the organosilicon compound coated on the silica particles suppresses the generation of the gap between the silica particles and the resin. Further, it is considered that the organosilicon compound hardens the bonds between the acrylic resins. From the above point of view, it is considered that it is possible to sufficiently suppress the occurrence of problems that occur during stretching such as dropout of silica particles and uneven orientation, and are excellent in moisture resistance and heat resistance.

[Suzy]

The resin constituting the resin film may contain a resin other than the acrylic resin if it contains an acrylic resin.

(Acrylic resin)

The acrylic resin is not particularly limited as long as it is a resin capable of exhibiting transparency to a resin film obtained by molding into a film. Specific examples thereof include resins obtained by polymerizing a monomer containing an acrylic monomer such as acrylic acid ester and methacrylic acid ester such as methyl methacrylate. More specifically, for example, methacrylic resins such as polymethyl methacrylate and the like can be given. The monomer preferably includes 50 to 99% by mass of methyl methacrylate and 1 to 50% by mass of other monomer copolymerizable with methyl methacrylate. Therefore, as the acrylic resin, a resin obtained by polymerizing a monomer containing 50 to 99 mass% of methyl methacrylate and 1 to 50 mass% of other monomer copolymerizable with methyl methacrylate is preferable.

Examples of other monomers copolymerizable with methyl methacrylate include, but are not limited to, alkyl methacrylates having 2 to 18 carbon atoms in the alkyl group, alkyl acrylates having 1 to 18 carbon atoms in the alkyl group, Unsaturated carboxylic acid such as unsaturated carboxylic acid such as α, β-unsaturated acid, maleic acid, fumaric acid and itaconic acid such as acrylic acid and acrylic acid, aromatic vinyl compound such as styrene and α-methylstyrene, acrylonitrile, methacrylonitrile Unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, and glutaric anhydride. These may be used alone or in combination of two or more. Of these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer Methyl acrylate or n-butyl acrylate is particularly preferable.

Commercially available acrylic resins may also be used. Specifically, for example, DELPET 60N manufactured by Asahi Chemical Industry Co., Ltd., Delpet 80N manufactured by Asahi Chemical Industry Co., Ltd., DAIANAL BR52 manufactured by Mitsubishi Rayon Co., Ltd., Mitsubishi Rayon Co., Ltd., DIANAL BR80 manufactured by Mitsubishi Rayon Co., Ltd., DAIANAL BR83 manufactured by Mitsubishi Rayon Co., Ltd., DAIANAL BR85 manufactured by Mitsubishi Rayon Co., Ltd., DAIANAL BR88 manufactured by Mitsubishi Rayon Co., Dianal MB-2539 manufactured by Mitsubishi Rayon Co., Ltd., Dianal BR64 manufactured by Mitsubishi Rayon Co., Ltd., Dianal BR75 manufactured by Mitsubishi Rayon Co., Ltd., and KT75 manufactured by Denki Kagaku Kogyo Co., have.

The acrylic resin may be used alone or in combination of two or more of the acrylic resins described above.

Further, even when a resin other than acrylic resin is contained in the resin film, the acrylic resin is not particularly limited as long as it is a resin capable of exhibiting transparency to a resin film obtained by molding into a film together with a resin other than acrylic resin Do not. Specifically, for example, an acrylic resin that can be contained in a resin film obtained in a state of compatibility with a resin other than an acrylic resin, and is preferably highly compatible. By using the above-mentioned acrylic resin having high compatibility and resin other than the acrylic resin in combination, properties of each resin can be supplemented to each other, and the obtained resin film can be given physical properties and quality required as optical films. Here, the fact that the acrylic resin and the resin other than the acrylic resin are contained in a compatible state means that each resin (polymer) is mixed, resulting in a state of compatibility.

Whether or not the acrylic resin and the resin other than the acrylic resin are in a commercial state can be specifically determined by, for example, measuring the glass transition temperature (Tg). More specifically, it is possible to judge from the following, for example. Even when the glass transition temperatures of the two resins are different from each other, when the compatibility of the two resins is high, one glass transition temperature is measured. That is, the inherent glass transition temperature of each resin disappears, and one glass transition temperature is measured. On the other hand, when the compatibility of the two resins is low, since the glass transition temperature of each resin is present, two or more glass transition temperatures of the mixture are measured. Here, the glass transition temperature used here is measured by a differential scanning calorimeter (DSC-7 type, manufactured by Perkin Elmer) at a temperature raising rate of 20 ° C / min and the midpoint glass transition, determined according to JIS K7121 (1987) Temperature (Tmg).

The acrylic resin preferably has a weight average molecular weight (Mw) of 70,000 to 1,000,000 from the viewpoints of improving the brittleness as a protective film for a liquid crystal polarizing plate and improving transparency when used in combination with a resin other than the acrylic resin. More preferably 150,000 to 400,000. The weight average molecular weight can be measured by gel permeation chromatography. The measurement conditions include, for example, the following conditions.

Solvent: methylene chloride

Column: Shodex K806 manufactured by Showa Denko K.K., Shodex K805 manufactured by Showa Denko K.K. and Shodex K803G manufactured by Showa Denko K.K.

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 manufactured by GL Science Co., Ltd.

Pump: L6000 manufactured by Hitachi Chemical Co., Ltd.

Flow rate: 1.0 ml / min

Calibration curves: 13 calibration samples (13 samples: suitable for use with substantially equal intervals of different Mw values) were prepared using 13 samples of standard polystyrene STK standard polystyrene (Mw = 2,800,000 to 500) manufactured by Tosoh Corporation.

The method for producing the acrylic resin is not particularly limited as long as the acrylic resin described above can be obtained. Specifically, it can be produced, for example, by polymerizing a monomer containing an acrylic monomer such as an acrylic acid ester and a methacrylic acid ester as described above by a known polymerization method. The polymerization method is not particularly limited, and examples thereof include suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization and the like. Here, the polymerization initiator used in the polymerization method is not particularly limited as long as it can initiate the polymerization reaction, and examples thereof include peroxide polymerization initiator, azo polymerization initiator and redox polymerization initiator . The polymerization temperature in the above-mentioned polymerization method is not particularly limited as long as it is a temperature at which the polymerization reaction can proceed. Concretely, for example, it is preferably 30 to 100 ° C in the case of suspension polymerization or emulsion polymerization, and 80 to 160 ° C in the case of bulk polymerization or solution polymerization. Further, in order to control the reduced viscosity of the obtained copolymer, alkylmercaptan or the like may be polymerized using a chain transfer agent.

(Resin other than acrylic resin)

The resin film may contain a resin other than the acrylic resin as described above. Examples of the resin other than the acrylic resin include a transparent resin, and specifically, a resin film excellent in transparency can be obtained even when it is contained together with an acrylic resin and molded into a film. More specifically, for example, cellulose ester-based resins such as cellulose diacetate resin, cellulose triacetate resin, cellulose acetate butyrate resin, and cellulose acetate propionate resin; Polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin; A polyolefin resin, a polyvinyl alcohol resin, an ethylene vinyl alcohol resin, a syndiotactic polystyrene resin, a cycloolefin resin, a poly (vinylidene chloride) resin, a polyolefin resin, Vinyl-based resins such as methylpentene resin; Polycarbonate resin; Polyarylate resins; Polyetherketone resins; Polyether ketone imide resins; Polyamide based resin; Fluorine-based resins, and the like. Of these, a cellulose ester-based resin is preferable. As the resin other than the acrylic resin, the above-mentioned transparent resin may be used alone or in combination of two or more.

(Cellulose ester resin)

Next, the cellulose ester resin will be described.

The cellulose ester resin is not particularly limited as long as it can exhibit transparency to a resin film obtained by being contained together with the acrylic resin and molded into a film. Specifically, from the viewpoints of, for example, improvement in brittleness and transparency when used in combination with an acrylic resin, substitution of an acyl group having an acyl group with a total substitution degree (T) of 2 to 3 and a carbon number of 3 to 7 Is preferably a cellulose ester-based resin having a degree of 1.2 to 3. The substitution degree of the acyl group having 3 to 7 carbon atoms is more preferably 2 to 3. That is, it is particularly preferable that the degree of substitution of the cellulose ester resin substituted with an acyl group having 3 to 7 carbon atoms is 2 to 3. Specific examples of the acyl group include a propionyl group and a butyryl group, and a propionyl group is preferably used.

When the total substitution degree (T) of the acyl group of the cellulose ester resin is too low, that is, when the residual degree of the hydroxyl group at the 2,3,6-positions of the cellulose ester molecule is too high, compatibility with the acrylic resin Becomes insufficient, and the haze of the obtained resin film tends to be high. When the substitution degree of the acyl group having 3 to 7 carbon atoms is too low even when the total substitution degree (T) of the acyl group is high, the compatibility with the acrylic resin becomes insufficient, or the brittleness of the obtained resin film is deteriorated . Specifically, for example, even when the total substitution degree of the acyl group is 2 or more, the substitution degree of the acyl group having 2 carbon atoms, for example, the acetyl group is high and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 , The compatibility is lowered and the haze tends to rise. Even when the total substitution degree of the acyl group is 2 or more, when the substitution degree of the acyl group having 8 or more carbon atoms is high and the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2, the brittleness is deteriorated, There is a tendency that it can not be obtained.

As described above, the cellulose ester-based resin preferably has a degree of substitution (T) of 2 to 3 and a degree of substitution of an acyl group having 3 to 7 carbon atoms of 1.2 to 3, More preferably the sum of the acetyl groups and the substitution degree of the acyl group having not less than 8 carbon atoms is 1.3 or less.

Further, the total substitution degree (T) of the acyl group of the cellulose ester resin is more preferably in the range of 2.5 to 3. [

The acyl group is not particularly limited and may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or branched or may have a substituent. The carbon number of the acyl group includes the carbon number of the substituent of the acyl group.

When the cellulose ester-based resin has an aromatic acyl group as a substituent, the number of substituents X to be substituted with an aromatic ring is preferably 0 to 5. Also in this case, the substitution degree of the acyl group having 3 to 7 carbon atoms including the carbon number of the substituent is preferably 1.2 to 3. Further, for example, when the benzoyl group has a carbon number of 7, when it has a substituent group containing carbon, the number of carbon atoms as the benzoyl group is 8 or more and is not included in the acyl group having 3 to 7 carbon atoms.

When the number of substituents substituted with aromatic rings is two or more, they may be the same or different. The condensed polycyclic compounds such as naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, chromene, chroman, phthalazine, acridine, indole, indoline and the like have.

The cellulose ester-based resin is not particularly limited as long as it is a cellulose ester-based resin as described above. Specifically, for example, a cellulose acetate propionate resin, a cellulose acetate butyrate resin, a cellulose acetate benzoate resin, a cellulose propionate resin, and a cellulose butyrate resin are preferably used. That is, a cellulose ester-based resin having an acyl group having 3 or 4 carbon atoms as a substituent is preferable. Of these, cellulose acetate propionate resin and cellulose propionate resin are particularly preferable. Further, the portion not substituted with an acyl group usually exists as a hydroxyl group.

The cellulose ester resin can be synthesized by a known method. The substitution degree of the acetyl group or the substitution degree of the other acyl group is a value measured by the method according to ASTM-D817-96.

The weight average molecular weight (Mw) of the cellulose ester-based resin is preferably 75000 or more, more preferably 75000 to 350000, further preferably 100000 to 240000 from the viewpoint of improving compatibility with an acrylic resin and improving embrittlement , And particularly preferably from 160000 to 240000. The cellulose ester resin may be used in combination of two or more kinds of cellulose ester resins. The weight average molecular weight (Mw) of the cellulose ester resin can be measured in the same manner as in the acrylic resin.

The content ratio of the acrylic resin and the cellulose ester resin in the case of containing the cellulose ester resin is preferably 95: 5 to 30:70 by mass ratio, more preferably 95: 5 to 50:50 And more preferably 90:10 to 60:40. If the content of the acrylic resin is too large with respect to the cellulose ester resin, the effect of the cellulose ester resin tends not to be sufficiently exhibited. If the content of the acrylic resin is too small relative to the cellulose ester resin, the effect of the acrylic resin can not be sufficiently exhibited. For example, moisture resistance of the obtained resin film tends to become insufficient.

(Silica particles)

The silica particles are not particularly limited as long as they are contained in the resin film and can exhibit an effect of suppressing the occurrence of blocking, that is, they function as an anti-blocking agent. The particle size of the silica particles is not particularly limited as long as it acts as an anti-blocking agent. Specifically, for example, it is preferable that the volume average primary particle diameter is 10 to 1000 nm. The volume average primary particle diameter can be measured using a general particle size meter or the like.

Specific examples of the silica particles include, for example, Aerosil-200, 200V, 300, R972, R972V, R974, R976, R976S, R202, R812, R505, OX50, TT600, RY50, RX50, NY50, NAX50, NA50H, NA50Y, NX90, RY200S, RY200, RX200, R8200, RA200H, RA200HS, NA200Y, R816, R104, RY300, RX300 and R106.

The silica particles exemplified above may be used alone or in combination of two or more. Specifically, silica particles having different particle diameters may be used in combination.

The content of the silica particles is preferably 0.1 to 2 parts by mass based on 100 parts by mass of the total amount of the resin contained in the resin film. When the content of the silica particles is too small, blocking can not be sufficiently suppressed when the resin film is rolled up and stored. This is considered to be because the silica particles contained in the resin film are too small and the slip property of the resin film can not be sufficiently increased. In addition, when the content of the silica particles is too large, there is a tendency that a winding deviation occurs when the resin film is rolled and stored. This is considered to be due to too much silica particles contained in the resin film, resulting in an excessively high slip property of the resin film. If the content of the silica particles is too large, the haze of the obtained resin film tends to be high.

(A silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate)

As described above, the resin film contains at least one member selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensate of the hydrolyzate.

(Silane coupling agent)

The silane coupling agent is not particularly limited. Specifically, it is preferable that a functional group having high affinity with a resin such as a reactive organic functional group or a polysulfide group can be imparted to the surface of the silica particle by reacting with the silica particle.

As the silane coupling agent, for example, a compound represented by the following formula (1) and a compound represented by the following formula (2) are preferable.

≪ Formula 1 >

In formula 1, Y represents a reactive organic functional group, R ¹ represents an alkyl group, OR ² is an an alkoxy group, m represents 1 or 2, n represents 0 or 1, m + n is from 1 to 3 .

(2)

In formula (2), R ³ represents an alkylene group, OR ⁴ represents an alkoxy group, p represents 1 to 5, and q represents 1 to 3.

The reactive organic functional group in the compound represented by the formula (1) is not particularly limited, but specific examples thereof include a vinyl group, an epoxy group, a styryl group, a methacryloxy group, an acryloxy group, A halogen group, a mercapto group, an isocyanate group, and the like. Of these, a functional group containing at least one of an amino group and a phenyl group is preferable. More specifically, for example, there can be mentioned -C ₃ H ₆ NHC ₂ H ₄ NH ₂ group, -C ₃ H ₆ NHPh group, and -Ph group. Ph represents a phenyl group.

The alkoxy group in the compound represented by the formula (1) is not particularly limited and includes an alkoxy group having 1 to 5 carbon atoms. Specific examples thereof include a methoxy group and an ethoxy group.

Specific examples of the compound represented by the formula (1) include KBM603 [(CH ₃ O) ₃ SiC ₃ H ₆ NHC ₂ H ₄ NH ₂ , manufactured by Shin-Etsu Chemical Co., Ltd., refractive index: 1.44 ], Shin-Etsu Chemical KBM602 of manufacture manufactured by Kogyo whether or _{[(CH 3 O) 2 (} CH 3) SiC 3 H 6 NHC 2 H 4 NH 2, refractive index 1.45], the production manufactured by Shin-Etsu Kagaku Kogyo whether or KBM573 [(CH ₃ O) ₃ SiC ₃ H ₆ NHPh, refractive index 1.5] and Z-6047 [Ph ₂ Si (OCH ₃ ) ₂ , refractive index 1.54] manufactured by Toray Dow Corning Toray Co.,

The alkylene group in the compound represented by the general formula (2) is not particularly limited and includes an alkylene group having 1 to 5 carbon atoms.

The alkoxy group in the compound represented by the general formula (2) is not particularly limited and includes an alkoxy group having 1 to 5 carbon atoms. Specific examples thereof include a methoxy group and an ethoxy group.

Specific examples of the compound represented by the formula (2) include Z-6940 [(C ₂ H ₅ O) ₃ SiC ₃ H ₅ -S ₄ -C ₃ , manufactured by Toray Dow Corning Toray Co., H ₅ Si (OC ₂ H ₅ ) ₃ , refractive index 1.49], and the like.

(Hydrolyzate of silane coupling agent)

The hydrolyzate of the silane coupling agent is not particularly limited as long as it is obtained by hydrolyzing the silane coupling agent. Specifically, the dope used in producing the resin film may contain the silane coupling agent and obtained by hydrolyzing the resin film during the production of the resin film. Therefore, the resin film may contain both the silane coupling agent and the hydrolyzate thereof.

(Polycondensation product of hydrolyzate of silane coupling agent)

The polycondensate of the hydrolyzate of the silane coupling agent is not particularly limited as long as the hydrolyzate is obtained by polycondensation. Concretely, the dope used in the production of the resin film may contain the silane coupling agent as described above, which is obtained by hydrolysis of the silane coupling agent during the production of the resin film and polycondensation of the hydrolyzate thereof. Therefore, the resin film may contain a polycondensate of the hydrolyzate as well as the silane coupling agent and the hydrolyzate thereof.

In addition, it is preferable that the refractive index of the silane coupling agent, the hydrolyzate of the silane coupling agent and the polycondensation product of the hydrolyzate, that is, the organic silicon compound, is 1.45 to 1.5. Specifically, for example, Shin-Etsu KBM602 of manufacture manufactured by Kogyo whether or Chemical Co. _{[(CH 3 O) 2 (} CH 3) SiC 3 H 6 NHC 2 H 4 NH 2, refractive index 1.45], Toray · Dow Corning whether or (C ₂ H ₅ O) ₃ SiC ₃ H ₅ -S ₄ -C ₃ H ₅ Si (OC ₂ H ₅ ) ₃ , refractive index 1.49] manufactured by Shin-Etsu Chemical Co., Ltd., KBM573 manufactured of _{[(CH 3 O) 3 SiC} 3 H 6 NHPh, refractive index 1.5] is used to the like are preferable. By using such an organosilicon compound as the organosilicon compound to be contained in the resin film, it is possible not only to sufficiently suppress the occurrence of problems at the time of stretching but also to obtain a resin film with more excellent transparency. This is considered to be due to the approximation of the refractive index of the resin constituting the resin film and the refractive index of the organic silicon compound. That is, when an organosilicon compound having an excessively low refractive index or an organosilicon compound having an excessively high refractive index is used, the difference between the refractive index and the refractive index of the resin constituting the resin film becomes large, and the transparency tends to decrease.

In addition, it is preferable that the refractive index of the silane coupling agent, the hydrolyzate of the silane coupling agent and the polycondensation product of the hydrolyzate, that is, the organic silicon compound, is 1.45 to 1.5. By using such an organosilicon compound as the organosilicon compound to be contained in the resin film, it is possible not only to sufficiently suppress the occurrence of problems at the time of stretching but also to obtain a resin film with more excellent transparency. This is considered to be due to the approximation of the refractive index of the resin constituting the resin film and the refractive index of the organic silicon compound. That is, when an organosilicon compound having an excessively low refractive index or an organosilicon compound having an excessively high refractive index is used, the difference between the refractive index and the refractive index of the resin constituting the resin film becomes large, and the transparency tends to decrease.

The total content of the silane coupling agent, the hydrolyzate of the silane coupling agent and the polycondensate of the hydrolyzate, that is, the content of the organosilicon compound is preferably 0.01 to 0.2 mass parts per 100 mass parts of the total amount of the resin contained in the resin film It is desirable to be wife. When the content of the organosilicon compound is too small, the effect of incorporating the organosilicon compound is reduced, and the occurrence of problems that may occur during elongation such as dislocation of silica particles and uneven orientation tends not to be sufficiently inhibited . If the content of the organic silicon compound is too large, the haze of the obtained resin film tends to be high. This is considered to be because, if the content of the organosilicon compound is too large, compatibility with other components of the resin film, for example, resin, is lowered.

(additive)

In addition, various additives may be appropriately added to the resin film so as to adjust its chemical properties, mechanical properties, electrical characteristics, and the like. Examples of the additive include acrylic particles, plasticizers, antioxidants, ultraviolet absorbers, and the like. Among them, it is preferable to contain acrylic particles. By containing the acrylic particles, it is possible not only to sufficiently suppress the occurrence of problems at the time of stretching but also to obtain a resin film excellent in workability and excellent in workability. Further, the obtained resin film is excellent in workability, so that, for example, when the end portion of the resin film is cut, the occurrence of cracks in the resin film can be suppressed.

(Acrylic particles)

Unlike the acrylic resin, the acrylic particles are not particularly limited as long as they do not dissolve in the solvent constituting the dope used for producing the resin film. Further, the acrylic particles are not dissolved in the resin solution (dope) in which the acrylic resin is dissolved. Specifically, for example, it is preferable that the resin film containing the acrylic resin contains particles of an acrylic resin existing in a state of particles, that is, in a non-use state. More specifically, for example, a predetermined amount of the obtained resin film is collected and stirred in a solvent to sufficiently dissolve the component dissolved in the solvent, and then the solution is poured into a solution of PTFE having pore size less than the volume average particle diameter of the acrylic particles It is preferable that the weight of the insoluble matter collected by filtration by filtration using a membrane filter is 90% by mass or more of the acrylic particles added to the resin film.

The acrylic particles are not particularly limited as long as they are the acrylic particles as described above. Specifically, for example, it is preferable that acrylic particles having two or more layer structures are formed, and in particular, a multi-layered acrylic granular composite as described later is preferable.

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 center toward the outer periphery. That is, the multi-layered acrylic particulate composite is a multi-layered acrylic particulate composite comprising a innermost hard layer, a crosslinked soft layer and an outermost hard layer from the center toward the outer periphery. A multi-layered acrylic granular composite having such a three-layer core shell structure is preferably used.

Preferred examples of the multi-layered acrylic particulate composite include the following. That is, the layers may be formed in the following manner.

Examples of the innermost hard layer polymer include: 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 polyfunctional grafting agent , And the like, and the like.

The crosslinked soft-layer polymer may be, for example, a polymer obtained by polymerizing in the presence of the innermost hard layer polymer 75 to 98.5% by mass of an alkyl acrylate having an alkyl group of 4 to 8 carbon atoms, 0.01 to 5% by mass of a polyfunctional crosslinking agent, And 0.5 to 5% by mass of a multifunctional grafting agent.

As the outermost hard layer polymer, for example, in the presence of the polymer comprising the innermost hard layer and the soft bridging layer, 80 to 99% by mass of methyl methacrylate and 1 to 8 And 1 to 20% by mass of an alkyl acrylate, which is obtained by polymerizing a mixture of monomers.

The multi-layered acrylic particulate composite in which the content ratio of each layer is 5 to 40% by mass of the innermost hard layer polymer, 30 to 60% by mass of the soft layer polymer, and 20 to 50% by mass of the outermost hard layer polymer desirable. Further, a multi-layered acrylic particle composite having an insoluble portion when fractionated by acetone and a swelling degree of methylethylketone of insoluble portion of 1.5 to 4 is more preferable.

Furthermore, as disclosed in Japanese Patent Application Laid-open No. 60-17406 or Japanese Patent Application Laid-Open No. 3-39095, not only the composition and particle diameter of each layer of the multi-layered acrylic particulate composite are specified, By setting the tensile modulus of elasticity of the composite or the swelling degree of methyl ethyl ketone in the acetone-insoluble portion within a specific range, it becomes possible to realize a balance between a sufficient impact resistance and a stress-relieving ability.

The innermost hard layer polymer includes, for example, 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- Or a mixture of two or more monomers. 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, Acrylate, and methyl acrylate and n-butyl acrylate are preferably used.

In addition, if the content of the alkyl acrylate in the innermost hard layer polymer is too low, the resulting heat resistance of the innermost hard layer polymer tends to increase. If the content of the alkyl acrylate is too high, the glass transition temperature of the innermost hard layer polymer is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite tends to be 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 preferable . The multifunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer. The blending ratio of the multifunctional grafting agent when used in polymerization of the innermost hard layer is preferably 0.01 to 0.3% by mass, for example.

As the crosslinked soft-layer polymer, it is possible to use, for example, in the presence of the innermost hard layer polymer, 75 to 98.5% by mass of an alkyl acrylate having an alkyl group of 1 to 8 carbon atoms, 0.01 to 5% by mass of a polyfunctional crosslinking agent, And 0.5 to 5% by mass of a 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.

Other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives. The ratio of the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group and the styrene is such that the larger the number of electrons, the lower the glass transition temperature of the crosslinked soft layer polymer, that is, the softened.

On the other hand, from the viewpoint of transparency of the resin composition, it is advantageous to bring the refractive index of the soft layer polymer at room temperature close to the innermost hard layer polymer, the outermost hard layer polymer and the acrylic resin. .

Examples of the multifunctional grafting agent include the same multifunctional grafting agents used in the preparation of the innermost layer hard polymer. The multifunctional grafting agent used herein is used for chemically bonding the soft layer polymer and the outermost hard layer polymer. The compounding ratio of the multifunctional grafting agent used in the innermost hard layer polymerization is preferably 0.5 to 5% by mass from the viewpoint of impact resistance imparting effect.

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

The polyfunctional crosslinking agent used herein is used for producing a crosslinked structure at the time of polymerization of the crosslinked soft layer polymer and exhibiting the effect of imparting impact resistance. However, when the above-mentioned multifunctional grafting agent is used at the time of polymerizing the crosslinked soft layer polymer, a polyfunctional crosslinking agent is not an essential component because it produces a crosslinked structure of the crosslinked soft layer polymer to some extent. When the polyfunctional crosslinking agent is used, the blending ratio of the polyfunctional crosslinking agent used in the polymerization of the crosslinked soft layer polymer is preferably from 0.01 to 5% by mass from the viewpoint of impact resistance imparting effect.

Wherein said outermost hard layer polymer comprises 80 to 99 mass% methyl methacrylate and 1 to 20 mass% alkyl acrylate having 1 to 8 carbon atoms in the alkyl group in the presence of said innermost hard layer polymer and said soft layer polymer Is preferably obtained by polymerizing a mixture of monomers.

As the acrylic alkylate, those described above are used, and methyl acrylate or ethyl acrylate is preferably used. The ratio of the alkyl acrylate units in the outermost hard layer polymer is preferably 1 to 20% by mass.

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

Particularly, in order to improve the balance between elongation and impact resistance, it is preferable to form a slope in the outermost hard layer, the molecular weight of which gradually decreases from the inside to the outside. As a specific method, the molecular weight of the polymer forming the outermost hard layer is determined by dividing the mixture of the monomers for forming the outermost hard layer into two or more and by sequentially increasing the amount of the chain transfer agent to be added at each time, It is possible to make the structure from the inside to the outside of the acrylic granular composite.

The molecular weight to be formed at this time may be measured by polymerizing the mixture of the monomers used in each cycle alone under the same conditions and measuring the molecular weight of the obtained polymer.

In the multi-layered acrylic particulate composite, the mass ratio of the core to the shell is not particularly limited. Specifically, for example, when the entirety of the multi-layer structure acrylic particulate composite is 100 mass parts, the core layer is preferably 50 mass parts or more and 90 mass parts or less, more preferably 60 mass parts or more and 80 mass parts or less. The term "core layer" as used herein refers to the innermost hard layer.

Specific examples of commercially available products of such a multi-layered acrylic particulate composite include Metabolene manufactured by Mitsubishi Rayon Co., Ltd., Ganease manufactured by Kaneka Corporation, Parabolite manufactured by Kureha Kabushiki Kaisha, Acrylate manufactured by Andhus, stapylloid manufactured by Gansu Kasei Kabushiki Kaisha, and parapet SA manufactured by Kabushiki Kaisha Kuraray. These may be used alone or in combination of two or more.

As the acrylic particles, graft copolymer particles are also preferably used. Specifically, the graft copolymer particles can be obtained, for example, by copolymerizing an unsaturated carboxylic acid ester monomer, an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and other vinyl compounds copolymerizable therewith And graft copolymer particles obtained by copolymerizing a mixture of monomers containing monomers.

Specific examples of the rubbery polymer include particles containing a diene rubber, an acrylic rubber, an ethylene rubber, and the like. More specifically, examples thereof include polybutadiene, styrene-butadiene copolymers, block copolymers of styrene-butadiene, acrylonitrile-butadiene copolymers, acrylic acid butyl-butadiene copolymers, polyisoprene, butadiene- Acrylate copolymers, ethylene-propylene copolymers, ethylene-isoprene copolymers, and ethylene-methyl acrylate copolymers, and the like. And the like. These rubbery polymers may be used alone or in combination of two or more.

Commercially available acrylic particles may also be used. Specifically, for example, METABOLEN W-341 manufactured by Mitsubishi Rayon Co., Ltd., KEMISUNO MR-2G manufactured by Soken Kagaku Kogyo K.K., and KEMISUNO MS-300X manufactured by Soken Kagaku Kogyo Co., .

The particle size of the acrylic particles is not particularly limited. Specifically, for example, the volume average particle diameter is preferably 10 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, and still more preferably 50 nm or more and 400 nm or less. The volume average particle diameter can be measured by a general particle size meter.

It is also preferable that the refractive index of the acrylic particles is close to the refractive index of the acrylic resin or the refractive index of the mixture of the acrylic resin and the cellulose ester resin in view of obtaining a film having high transparency. Specifically, for example, the difference in refractive index between the acrylic particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and even more preferably 0.01 or less.

In order to satisfy the condition of the refractive index as described above, a method of adjusting the composition ratio of each monomer unit of the acrylic resin and a method of preparing the composition of the rubber polymer or monomer used in the acrylic particle can be mentioned. By doing so, the refractive index difference can be made small, and a protective film for a liquid crystal polarizing plate excellent in transparency can be obtained.

Incidentally, the refractive index difference mentioned here means that the protective film for a liquid crystal polarizing plate according to the present invention is sufficiently dissolved in a solvent in which an acrylic resin is soluble to obtain a cloudy solution which is insolubilized with solvent- (23 占 폚, measurement wavelength: 550 nm) after purification of the soluble part (acrylic resin) and the insoluble part (acrylic particle).

The content of the acrylic particles is preferably 0.5 to 30 parts by mass, more preferably 1 to 15 parts by mass based on 100 parts by mass of the total amount of the resin contained in the resin film. If the content of the acrylic particles is too small, the effect of containing the acrylic particles is reduced, and the effect of increasing the toughness or the like and increasing the workability tends not to be sufficiently exhibited. When the content of the acrylic particles is too large, there is a tendency that the acrylic particles fall off at the time of drawing.

(Plasticizer)

The plasticizer is not particularly limited, but may be added for imparting appropriate flexibility to the obtained resin film. Specific examples thereof include ester plasticizers, phosphoric acid ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolic acid ester plasticizers, citric ester plasticizers, and the glycol-based plasticizers And the like.

Specific examples of the ester plasticizers include polybasic acids such as aliphatic dibasic acids, alicyclic dibasic acids, and aromatic dibasic acids, and polyhydric alcohols such as glycols. Examples of the aliphatic dibasic acids include, but are not limited to, adipic acid, sebacic acid, phthalic acid, terephthalic acid, and 1,4-cyclohexyldicarboxylic acid.

Specific examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like. .

Specific examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate and butyl benzyl phthalate. have.

Specific examples of the trimellitic acid plasticizer include tributyl trimellitate, triphenyl trimellitate, triethyl trimellitate and the like.

Specific examples of the pyromellitic acid ester plasticizer include tetrabutyl pyromellitate, tetraphenyl pyromellitate, and tetraethyl pyromellitate.

Specific examples of the glycolic acid ester plasticizer include triacetin, tributyltin, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate and the like.

Specific examples of the citrate ester plasticizer include triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri- -Ethylhexyl) citrate and the like.

Examples of the glycol-based plasticizer include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, -Butylene glycol, and the like.

The above plasticizers may be used alone or in combination of two or more.

(Antioxidant)

The antioxidant is not particularly limited, and for example, a hindered phenol-based compound is preferably used. Specific examples thereof include 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butyl anilino) - (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3 N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrosinnamide), 1 (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- Benzyl) -isocyanurate and the like. Particularly preferred are 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t- Glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]. Further, for example, a hydrazine-based metal inactive agent such as N, N'-bis [3- (3,5-di-t-butyl- 4- hydroxyphenyl) propionyl] hydrazine, Di-t-butylphenyl) phosphite may be used in combination.

(Ultraviolet absorber)

Examples of the ultraviolet absorber include those having an action to prevent deterioration of a polarizing plate or a liquid crystal cell when the obtained resin film is used as a protective film for a polarizing plate. Concretely, it is preferably used that the absorption ability of ultraviolet rays having a wavelength of 370 nm or less is excellent and the absorption of visible light having a wavelength of 400 nm or more is small, from the viewpoint of good liquid crystal display properties. Specifically, the transmittance at 380 nm is preferably less than 10%, more preferably less than 5%.

Specific examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds (benzotriazole ultraviolet absorbers), salicylic ester compounds, benzophenone compounds (benzophenone ultraviolet absorbers), cyano Acrylate compounds, nickel complex salt compounds, triazine compounds, and the like.

Among the above ultraviolet absorbers, benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers are preferred. Specific examples of the benzotriazole ultraviolet absorber and the benzophenone ultraviolet absorber are mentioned below, but the present invention is not limited thereto.

Specific examples of the benzotriazole ultraviolet absorber include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'- butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (3 '', 4 '', 5 ", 6" -tetrahydrophthalimidemethyl) -5'-chlorobenzotriazole, (Methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol- (Straight chain and branched chained dodecyl) -4-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol- -Methylphenol (TINUVIN 171, manufactured by BASF Japan Ltd.), octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate Mixture of agent (TINUVIN 109, BASF Japan Co., Ltd.) and the like.

Specific examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4- 5-sulfobenzophenone, and bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane).

Next, the production method of the resin film will be described.

The production method of the resin film is not particularly limited as long as it is possible to produce a resin film containing the acrylic resin, the silica particles and the organic silicon compound. Specifically, for example, a resin film can be prepared by a solution casting method or the like using a resin solution (dope) containing the acrylic resin, the silica particles and the organic silicon compound. Further, as described above, the silane coupling agent may be a hydrolyzate hydrolyzed at the time of production of the film or a polycondensate of the hydrolyzate thereof, as the organic silicon compound contained in the resin film. Further, the silane coupling agent is more likely to be uniformly dispersed in the dope as compared with a hydrolyzate or a polycondensate. From this, the organosilicon compound to be contained in the dope may be any one of the silane coupling agent, the hydrolyzate of the silane coupling agent and the polycondensation product of the hydrolyzate, but the silane coupling agent is preferable. As a method for producing the above-mentioned resin film, there is, for example, a method of producing a flexible film by forming a flexible film on a support on which a resin solution (dope) containing the acrylic resin, the silica particles and the silane coupling agent is run, A peeling step of peeling the flexible film from the support as a film; and a stretching step of stretching the peeled film in a direction perpendicular to the transport direction of the film. For example, by an apparatus for producing a resin film by a solution casting film forming method as shown in Fig. Further, the apparatus for producing a resin film is not limited to the one shown in Fig. 1, but may be of another constitution. Here, the film refers to a film after a flexible film (web) comprising a resin solution (dope) softened on a support is dried on a support and is in a state in which it can be peeled off from the support. Method and the like.

1 is a schematic view showing an example of a basic configuration of a resin film production apparatus 11 for producing a resin film according to the present embodiment. The resin film production apparatus 11 includes a dope producing apparatus 21, a Dope filtering apparatus 22, and a film forming apparatus 23. The dope producing apparatus 21 produces a dope. The Dopp filtration device 22 filters the produced dope. The film-forming apparatus 23 uses the filtered dope to produce a resin film.

(Dope producing apparatus)

As shown in Fig. 1, the dope producing apparatus 21 includes a dope introducing furnace 1, a discharge valve 6, a dope delivery pump 2, and the like. The dope applying furnace 1 is a container for producing a dope by mixing a raw material of a resin film such as a resin and a dope raw material containing a solvent. As the raw material of the resin film used herein, the above-mentioned raw materials such as the acrylic resin, the silica particles and the silane coupling agent are used. The solvent used here is not particularly limited as long as it is a solvent capable of dissolving the acrylic resin. Specific examples of the solvent include chlorinated organic solvents such as methylene chloride and organic solvents such as methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, Ethyl, 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- And non-chlorine-based organic solvents such as propanol and nitroethane. Of these, methylene chloride, methyl acetate, ethyl acetate, and acetone are preferred.

It is preferable that the solvent contains a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. The content thereof is preferably 1 to 40 mass% with respect to the whole solvent. If the content of the alcohol in the dope is high, the web gelled and the separation from the metal support becomes easy. When the content of the alcohol is low, the acrylic resin or the cellulose ester resin To promote the dissolution of.

Further, 15 to 45 mass% of a raw material for the resin film such as the acrylic resin, the silica particles and the organic silicon compound is dissolved in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms It is preferable that the doping is performed.

Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert- .

The piping 7 for circulating the dope through the discharge valve 6 and for feeding the dope to another apparatus such as the Dopp filtration apparatus 22 is connected to the dope charging furnace 1 . The piping 7 is connected to the flexible die 13 of the film forming apparatus 23 via the DOP filtration apparatus 22 or the like. The piping 7 is provided with a doped liquid feed pump 2 for efficiently allowing the dope to flow through the piping 7 directly below the discharge valve 6. [ The above-described liquid-delivery pump 2 may be disposed not only directly below the discharge valve 6 but also appropriately to facilitate the flow of the dope in the pipe 7.

The dope applying furnace 1 can be used without limitation, such as a kiln used as a dope charging furnace. As the dope feeding furnace 1, it is preferable that the liquid injected into the furnace can be heated to a predetermined temperature and stirred under heating. Specifically, for example, those equipped with a stirring blade, a heating device, and the like can be given. The heating apparatus for heating the liquid in the dope feeding furnace 1 is not particularly limited, but is preferably performed from the outside. For example, a jacket type is preferable in that temperature control is easy. In addition, in the case where the liquid to be charged into the dope feeding pot 1 is stirred while being heated, it is preferable that the dope feeding pot 1 is a closed container in order to suppress the loss of the solvent. In such a case, it is preferable that the dope feeding furnace (1) is a container capable of withstanding a predetermined pressure, specifically, a pressure of the solvent equal to or higher than a vapor pressure at a temperature during stirring. The pressurization in the dope applying furnace 1 may be carried out by raising the vapor pressure of the solvent by heating as described above, but a method of pressurizing an inert gas such as nitrogen gas or the like may also be used. In addition, a meter such as a pressure gauge, a thermometer, and a viscometer may be appropriately disposed in the dope supplying furnace 1. [

Next, a method of manufacturing the dope by the dope producing apparatus 21 will be described.

A dope starting furnace (1) is charged with a dope raw material such as a resin and a solvent and stirred. At this time, the dope raw materials other than the resin and the solvent may be added before the agitation or may be added during the agitation. By doing so, the resin slowly dissolves in the solvent. Thus, the resin is dissolved in the solvent to prepare a dope. The viscosities of the liquid in the dope charging furnace 1 can be measured using a viscometer placed in the dope charging furnace 1, for example, FVM-80A-EXHT manufactured by CBC Chemical Co.,

The temperature of the liquid in the dope applying furnace 1 is not particularly limited, but it is preferably at least the boiling point of the main solvent in the solvent, for example, the chlorine solvent, from the viewpoint of enhancing the solubility of the resin. It is more preferable that the temperature is higher than 20 to 50 占 폚. If the temperature of the liquid at the time of stirring is too low, the time required for the resin to dissolve is prolonged, and the productivity of the dope tends to be lowered. In addition, if the temperature of the liquid at the time of stirring is too high, the bubbles generated by the boiling of the solvent tend to remain in the obtained dope, and foreign matter due to bubbles tends to be generated in the obtained resin film. The temperature of the liquid in the dope applying furnace 1 can be measured using a thermometer or the like arranged in the dope charging furnace 1. [ Further, for example, the temperature of the liquid in the dope charging furnace 1 may be measured using FVM-80A-EXHT manufactured by CBC Chemical Co., Ltd., which is an example of the above-described viscometer.

The capacity of the dope charging furnace 1 is preferably 2 to 50 m ³ , and more preferably 5 to 20 m ³ . If the capacity is too small, it may be necessary to increase the number of the dope dosing kilns or to increase the number of dope processing depending on the amount of dope produced. On the other hand, if it is too large, the time required for dissolving the resin in the solvent is prolonged and the productivity of the dope tends to be lowered.

The dope manufactured by the dope supplying kiln 1 is delivered to the Doped filtration apparatus 22 through the pipe 7 connected to the dope charging furnace 1 by opening the discharge valve 6 , And then fed to the film-forming apparatus 23, specifically, the flexible die 13 of the film-forming apparatus 23.

(Doped filtration device)

As shown in Fig. 1, the Doped Filtering Apparatus 22 includes a doping furnace 3, a filter 4, a dope feed pump 2, and the like. In the case where the dope produced by the dope producing apparatus 21 does not generate undissolved products or precipitates, it is not necessary to provide the Dope filtering apparatus 22. However, in order to reduce the generation of foreign matter in the obtained resin film It is preferable to install the Dopp filtration device 22.

The doping furnace 3 is a container for temporarily storing the dope. The viscosity of the liquid in the doping furnace 3, for example, the dope produced beforehand in the dope feeding furnace 1 and fed to the film forming apparatus 23, For example, FVM-80A-EXHT manufactured by CBC Corporation. Here, the viscosity of the dope indicates the viscosity at 30 占 폚. The filter is a filter for filtering and separating undissolved matter or precipitate from the dope stored in the doping furnace (3). 1, the filter provided in the DOP filtration device 22 may be one filter, or two or more filters may be connected in series or in parallel. The material of the filter material used in the filter provided in the Dope filter device 22 is not particularly limited and a typical filter material can be used. For example, a filter material made of plastics such as polypropylene, a filter paper made of cellulose or rayon, or a metal filter material made of stainless steel or the like is preferable because the fiber does not fall off. The filtration is preferable in that the impurities contained in the solution of the resin as the raw material, in particular the foreign matter, are removed and reduced. The filtration accuracy is preferably 0.03 mm or less, more preferably 0.001 to 0.015 mm. Further, when a plurality of filters are used as described above, it is preferable to provide one filter of 0.002 to 0.005 mm.

The doped liquid feed pump 2 may be appropriately arranged to smooth the feeding of the dope in the pipe 7 or the like to the pipe 7 connecting the doffing furnace 3 and the filter. Particularly, immediately before the filter such as the filter 4, it is preferable that the doped liquid feed pump 2 is disposed in order to increase the pressure.

Therefore, the dope produced by the dope producing apparatus 21 is filtered by the Dope filtering apparatus 22 and then supplied to the film forming apparatus 23, specifically to the flexible die 13 of the film forming apparatus 23 Is sent.

(Film forming apparatus)

The film forming apparatus 23 includes an endless belt support 12, a flexible die 13, a peeling roller 14, a stretching device 15, a drying device 17, and a winding device 18, And the like. The flexible die 13 softens the dope 19 on the surface of the endless belt support 12. The endless belt support 12 forms a web including a flexible dope 19 from the flexible die 13, and dries the web by conveying it. The peeling roller 14 peels the film from the endless belt support 12. The stretching device (15) stretches the peeled film. The drying device 17 dries the stretched film while conveying it by a conveying roller. The winding device 18 winds the dried film in a roll form to form a film roll. Here, as the dope 19, dope prepared by the dope producing apparatus 21, filtered by the Dope filtering apparatus 22 as necessary and fed to the film forming apparatus 23 is used.

The flexible die 13 is supplied with a dope 19 from a dope supply pipe connected to the upper end of the flexible die 13, as shown in Fig. Then, the supplied dope is discharged from the flexible die 13 to the endless belt support body 12, and a web is formed on the endless belt support body 12.

As shown in Fig. 1, the endless belt support 12 is an endless belt made of metal running on an infinitely curved surface. As the belt, a belt made of, for example, stainless steel or the like is preferably used from the viewpoint of film peelability. The width of the flexible film which is flexible by the flexible die 13 is not particularly limited but is preferably 80 to 99% of the width of the endless belt support 12 from the viewpoint of effectively utilizing the width of the endless belt support 12 . Instead of the endless belt support, a rotating metal drum (endless drum support) whose surface is mirror-finished may also be used.

Then, the endless belt supporter 12 dries the solvent in the dope while conveying the flexible film (web) formed on the surface thereof. The drying is carried out, for example, by heating the endless belt support 12 or spraying heated air on the web. The higher the temperature of the web is, the faster the drying speed of the solvent can be, while the higher the temperature, the lower the foaming or flatness tends to deteriorate.

In the case of heating the endless belt support 12, for example, a method of heating the web on the endless belt support 12 with an infrared heater, a method of heating the back surface of the endless belt support 12 with an infrared heater, A method of blowing a heated air on the back surface of the substrate 12 to heat it, and the like, and it is possible to appropriately select it if necessary.

Further, in the case of blowing hot wind, the wind pressure of the heated wind is preferably 50 to 5000 Pa in consideration of the uniformity of evaporation of the solvent and the like. The temperature of the heated wind can be dried at a constant temperature or divided into several temperatures in the running direction of the endless belt support 12. [

The duration of time from the endless belt support 12 to the moment the web is separated from the endless belt support 12 after the dope is plied on the endless belt support 12 varies depending on the thickness of the resin film to be produced and the solvent used, Is preferably in the range of 0.5 to 5 minutes in consideration of the peelability from the base material (12).

The running speed of the endless belt support 12 is not particularly limited, but it is preferably about 50 to 200 m / min, for example, from the viewpoint of productivity. It is preferable that the ratio of the running speed of the endless belt support 12 to the flow rate of the dope discharged from the flexible die 13 (draft ratio) is about 0.8 to 2. When the draft ratio is within this range, a flexible film can be stably formed. For example, if the draft ratio is too large, the flexible film tends to cause a phenomenon called neck-in which is reduced in the width direction, and as a result, a wide film can not be formed.

The distance between the endless belt support 12 and the peeling roller 14 is preferably in the range of 1 to 100 mm, . Using the peeling roller 14 as a fulcrum, the dried web (film) is stretched by applying tension to peel off the dried web (film). When the film is peeled off from the endless belt support 12, the film is stretched in the film carrying direction (machine direction: MD direction) by the peeling tension and the subsequent transporting tension. Therefore, the peel tension and the transport tension when peeling the film from the endless belt support 12 are preferably set to, for example, 50 to 400 N / m.

The residual solvent ratio of the film when the film is peeled off from the endless belt support body 12 is determined by the peelability from the endless belt support body 12, the residual solvent ratio upon peeling, the transportability after peeling, It is preferably 30 to 200% by mass in consideration of the physical properties and the like of the optical film to be formed. Further, the residual solvent ratio of the film is defined by the following formula (I).

≪ EMI ID =

Residual solvent ratio (mass%) = {(M ₁ -M ₂ ) / M ₂ } × 100

Here, M ₁ represents the mass of the film at an arbitrary point in time, and M ₂ represents the weight of the film after drying the film measured at M ₁ at 115 ° C. for 1 hour.

The stretching device 15 stretches the film peeled off from the endless belt support 12 in a direction (Transverse Direction: TD direction) perpendicular to the conveying direction of the web. More specifically, both ends in the direction perpendicular to the transport direction of the film are gripped with a clip or the like, and the distance between the opposing clips is increased to stretch in the TD direction. Although the stretching device 15 is provided in the first embodiment, it may be omitted. At this time, it is preferable to stretch so that the elongation determined by the following formula (II) becomes 10 to 200%. That is, it is preferable that the finally obtained resin film is stretched so as to satisfy the following formula (II).

≪ EMI ID =

Elongation (%) = {(length in the width direction after stretching - length in the width direction before stretching) / length in the width direction before stretching} x 100

If the elongation is too low, a desired retardation tends to be difficult to obtain. This is considered to be due to the fact that if the elongation is too low, the orientation of molecules constituting the resin film is insufficient. In addition, if the elongation is too high, the film thickness irregularity of the web tends to become remarkable. Thereby, there is a possibility that the obtained resin film is uneven in phase difference. In addition, the haze of the film increases, and the transparency tends to decrease. Therefore, when the obtained optical film is used as a retardation film provided in a liquid crystal display device such as a liquid crystal panel, contrast tends to be lowered, which is not preferable. Further, in some cases, there is a fear that the film is torn and broken at a portion gripped by the gripping means (clip). Therefore, by stretching to be within the above-mentioned range, it is possible to obtain a resin film which is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems during stretching, and has a wide width. When such a resin film containing silica particles is stretched at such a high elongation, there is a tendency that problems such as dropout of silica particles and uneven orientation tend to occur. In the case of the resin film according to this embodiment, Can be suppressed.

When the film is stretched, the film is usually heated. Heating of the film may be performed, for example, by blowing heated air onto a film, or may be heated by a heating device such as an infrared heater. The temperature (stretching temperature) at which the stretching is carried out is preferably 100 to 200 占 폚, more preferably 120 to 180 占 폚. If the stretching temperature is too low, excessive stress is applied to the film, so that the haze of the film increases and the transparency tends to decrease. Therefore, when the obtained resin film is used as a retardation film provided in a liquid crystal display device such as a liquid crystal panel, the contrast tends to be lowered, which is not preferable. Further, in some cases, there is a fear that the film is torn and broken at a portion gripped by the gripping means (clip). If the stretching temperature is too high, a desired retardation value can not be obtained, or the film is melted, and the surface state of the film and the film thickness tend to become uneven.

Further, the stretching device 15 may be provided with a device for cutting the area holding the clip. In the present embodiment, the stretching device 15 is provided, but it may not be provided.

The total residual solvent ratio of the film stretched by the stretching device 15 is not particularly limited, but is preferably 1 to 20% by mass, for example, from the viewpoint of workability by the drying device 17 . When the stretching device 15 is not provided, it is preferable that the total residual solvent ratio of the film is 1 to 20% by mass until the film is supplied to the drying device 17.

The drying device 17 has a plurality of conveying rollers, and dries the film while conveying the film between the rollers. In the present embodiment, as described later, a film corresponding to each dope of a plurality of doughs having different compositions is peeled off from the endless belt support 12, and the drying conditions are changed so as to have a predetermined residual solvent ratio , And a step of drying the resin film. By doing so, a resin film corresponding to each dope is preferably produced. Concretely, it is preferable that the residual solvent ratio is set to be 0.01 to 15% by mass to be described later. In drying, heating air, infrared light, and the like may be used alone or in combination with heating air and infrared light. It is preferable to use heated air in terms of simplicity. The drying temperature may be appropriately selected depending on the residual solvent ratio in the range of 30 to 180 占 폚 in consideration of the drying time, the shrinkage unevenness, the stability of the elongation and expansion, and the like, depending on the residual solvent ratio of the film . In addition, it may be dried at a constant temperature, or may be divided into two to four steps and dried at several temperatures. Further, while being conveyed into the drying device 17, the film may be stretched in the MD direction. The residual solvent ratio of the film after the drying treatment in the drying apparatus 17 is preferably 0.01 to 15% by mass in consideration of the load of the drying step, the dimensional stability expansion ratio at the time of storage, and the like.

In the winding device 18, a film having a predetermined residual solvent ratio is subjected to embossing at both end portions in the width direction thereof by a hot embossing mechanism in the drying device 17, and then wound in a winding manner. The temperature at the time of winding is preferably cooled to room temperature in order to prevent friction scratches due to shrinkage after winding, looseness, and the like. The winding machine to be used can be used without particular limitation, and can be generally used, and can be wound by a winding method such as a squatting method, a constant torque method, a taper tension method, an internal stress, and a constant program tension control method.

Although the film-forming apparatus 23 includes the elongating device 15 and the drying device 17, the film-forming device 23 may be omitted or may be provided at two or more places.

As described above, even if the resin film thus obtained is stretched, it is possible to sufficiently inhibit the occurrence of problems such as dropout of silica particles and uneven orientation. Therefore, the resin film is excellent in moisture resistance and heat resistance, can sufficiently suppress the occurrence of problems in stretching, and can obtain a resin film having a wide width. In addition, when the resin film containing silica particles is stretched at such a high elongation as described above, there is a tendency that problems such as dropout of silica particles and uneven orientation tend to occur in general. In the resin film according to the present embodiment, , The occurrence of such a problem can be suppressed.

(Polarizer)

The resin film can be used as a transparent protective film for a polarizing plate for protecting a polarizing element of a polarizing plate in accordance with its composition and the like. The polarizing plate specifically includes, for example, a polarizing element and a transparent protective film disposed on the surface of the polarizing element. As the transparent protective film, the above resin film can be used. The polarizing element is an optical element that converts incident light into polarized light and emits the polarized light.

As the polarizing plate, for example, a polarizing element produced by dipping a polyvinyl alcohol-based film in an iodine solution and stretching the polarizing element, and a resin obtained by bonding a completely saponified polyvinyl alcohol aqueous solution to at least one surface of the polarizing element desirable. Further, the resin film may be laminated on the other surface of the polarizing element, or a transparent protective film for a polarizing plate may be laminated. As the transparent protective film for the polarizing plate, for example, commercially available cellulose ester films such as KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UY-HA and KC8UX-RHA (manufactured by Konica Minolta Opto Chemical Co., ) Is preferably used. Alternatively, a resin film such as a cyclic olefin resin other than a cellulose ester film, an acrylic resin, a polyester, or a polycarbonate may be used. In this case, since the saponification suitability is low, it is preferable to perform bonding processing to the polarizing plate through a suitable adhesive layer.

As described above, the polarizing plate is a transparent protective film laminated on at least one surface side of the polarizing element, and the resin film is used. At that time, when the resin film functions as a retardation film, it is preferable that the slow axis of the resin film is disposed so as to be substantially parallel or orthogonal to the absorption axis of the polarizing element.

Specific examples of the polarizing element include, for example, a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film is obtained by staining a polyvinyl alcohol film with iodine and dyed with a dichromatic dye. As the polyvinyl alcohol-based film, a modified polyvinyl alcohol-based film modified with ethylene is preferably used.

The polarizing element is obtained, for example, as follows. First, a film is formed using a polyvinyl alcohol aqueous solution. The resulting polyvinyl alcohol-based film is uniaxially stretched, then dyed or dyed, and then uniaxially stretched. The durability treatment is preferably performed with a boron compound.

The film thickness of the polarizing element is preferably 5 to 40 탆, more preferably 5 to 30 탆, and still more preferably 5 to 20 탆.

When the cellulose ester based resin film is to be bonded on the surface of the polarizing element, it is preferable to bond it with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like. Further, in the case of a resin film other than the cellulose ester-based resin film, it is preferable to perform bonding processing to the polarizing plate through a suitable adhesive layer.

Since the above-mentioned polarizing plate uses the resin film according to the present embodiment as a transparent protective film, the resin film is excellent in moisture resistance and heat resistance, and the occurrence of problems during stretching is suppressed. Therefore, for example, , A polarizing plate which can be preferably used for a large-screen liquid crystal display device is obtained. Specifically, even a polarizing plate for a large-screen liquid crystal display device is prevented from being deformed due to moisture absorption.

(Liquid crystal display device)

Further, the polarizing plate provided with the resin film can be used as a polarizing plate provided in a liquid crystal display device. Specifically, the liquid crystal display device includes, for example, a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell therebetween. The polarizing plate may be used as at least one polarizing plate among the two polarizing plates. The liquid crystal cell is a liquid crystal material filled between a pair of electrodes. When a voltage is applied to the liquid crystal cell, the alignment state of the liquid crystal is changed, and the amount of transmitted light is controlled. Such a liquid crystal display device uses a polarizing plate having a resin film which is excellent in moisture resistance and heat resistance and suppresses the occurrence of problems at the time of stretching. Therefore, even if the polarizing plate is made into a large screen, It is possible to provide a liquid crystal display device in which the occurrence of problems of the resin film as the liquid crystal display device is suppressed. Specifically, for example, even in a liquid crystal display device having a large screen, it is possible to suppress the occurrence of deformation of the resin film disposed in the image display area due to moisture absorption.

Example

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

[Example A]

First, the effect of an organic silicon compound in a resin film containing an acrylic resin and silica particles was examined.

(Example 1)

First, 300 parts by mass of methyl chloride and 52 parts by mass of methanol were added to a container (dissolution tank) of a production apparatus for a resin film as shown in Fig. 1, and an acrylic resin (methyl methacrylate resin: (Dainal BR100, manufactured by Rayon Co., Ltd., weight average molecular weight (Mw): 120000) was added and stirred. Further, 0.5 part by mass (0.5 parts by mass with respect to 100 parts by mass of the resin) of silica particles (972 V of Aerosil, manufactured by Nippon Aero Chemical Co., Ltd., volume average primary particle diameter: 16 nm) agent (Shin-Etsu manufactured in the manufacturing KBM602, either high or wrong Chemical _{(CH 3 O) 2 (CH} 3) SiC 3 H 6 NHC 2 H 4 NH 2, refractive index 1.45), 0.05 parts by mass (resin based on 100 parts by mass of 0.05 mass Part) was added. Then, the mixture was stirred until the transparent resin dissolved, whereby a dope (resin solution) was obtained. The obtained dope was cooled to 35 DEG C and then filtered.

Using the thus obtained dope, a resin film was produced as follows.

First, the dope is fed into a flexible die (coat hanger die) through a pipe, and the dope is softened by an endless belt support made of a stainless steel and an endless belt polished by a hard surface from a flexible die (coat hanger die) . By doing so, a web was formed on the endless belt support, and was conveyed while being dried. Then, the web was peeled off as a film from the endless belt support. At that time, it was dried so that the residual solvent ratio of the web at the time of peeling was 100%.

Then, the peeled film was dried while being rolled and conveyed in an atmosphere at 35 캜. Thereafter, the film was stretched 1.1 times in the width direction while grasping both ends of the film with a clip in an atmosphere of 135 캜 using a stretching device (tenter). Then, the stretched film was relaxed at 130 占 폚 for 5 minutes, and then dried while being rolled and transported in an atmosphere of 120 占 폚 or 140 占 폚.

Thereafter, the area held by the clip was cut using a cutting device to obtain a film having a width of 1.5 m. Then, the obtained film was wound up by a winding device to obtain a roll-shaped resin film.

(Comparative Example 1)

The same as in Example 1 except that no silane coupling agent is contained in the dope.

Table 1 summarizes the dope compositions in Example 1 and Comparative Example 1. [

The resin film obtained as described above was evaluated as follows.

(Desorption of silica particles)

First, a black cloth was pushed onto the obtained resin film. Then, the resin film was reciprocated 20 times to rub the resin with the cloth pressed. Thereafter, the surface pressed against the resin film of the cloth was visually confirmed. At that time, when the white point derived from the silica particle could not be confirmed, it was evaluated as "? &Quot;, and when the white point was confirmed, it was evaluated as "

(Orientation unevenness)

The obtained resin film was disposed between two polarizing plates which were orthogonal (cross-Nicol) state, light was shone on one polarizing plate side with a Schaukasten, and the other was observed with the naked eye on the other polarizing plate side. As a result, if unevenness is not confirmed, it is evaluated as "? &Quot;, and nonuniformity is slightly confirmed at the periphery of the end portion but is not confirmed at the central portion and is evaluated as " Was evaluated as " DELTA ", and when severe unevenness was confirmed, it was evaluated as "x ".

(Moisture resistance)

As a display of two portions aligned in the flexible direction (longitudinal direction) of the obtained resin film, two cross marks were placed. And the distance between the indications of the two sites was measured using an optical microscope.

The resin film thus marked was subjected to heat treatment by being left in an atmosphere at 60 캜 and a relative humidity of 90% RH for 1000 hours. Thereafter, the distance between the indications of the two sites was again measured using an optical microscope.

Using the distance between the displays measured as described above, the rate of change (rate of dimensional change) of the distance was calculated from the following equation (2).

&Quot; (2) "

Dimensional change ratio (%) = [(L1-L2) / L1] 100

In the formula, L1 represents the distance before the heat treatment, and L2 represents the distance after the heat treatment.

When the dimensional change rate is less than 0.3%, it is evaluated as "? &Quot;, and when it is 0.3% or more and less than 0.5%, it is evaluated as "? &

(Heat resistance)

First, the obtained resin film was cut into a size of 10 cm x 10 cm. Then, the cut resin film was used as a test piece. The test piece was allowed to stand in an atmosphere at 90 캜 in a dry state (relative humidity of 5% RH or less) for 1000 hours. Thereafter, the deformation of the film was visually confirmed. The film was evaluated as " DELTA "when the film was confirmed to be deformed and the film was evaluated as" x "

The evaluation results are shown in Table 2.

As can be seen from Tables 1 and 2, the resin film (Example 1) containing an acrylic resin, silica particles and an organosilicon compound is a resin film containing no organosilicon compound (Comparative Example 1) The elution of the silica particles was suppressed even when stretched, and the occurrence of orientation unevenness was suppressed. From this, it was found that by containing an acrylic resin, silica particles and an organic silicon compound, not only the moisture resistance and the heat resistance were excellent, but also the occurrence of problems at the time of drawing was sufficiently suppressed.

[Example B]

Next, the case of containing a cellulose ester resin was examined.

(Examples 2 to 25)

Examples 2 to 25 were obtained in the same manner as in Example 1 except that as the transparent resin, a mixture of the acrylic resin shown in Table 3 and the cellulose ester resin shown in Table 3 in the proportion shown in Table 3 (composition ratio) .

In Table 3, T represents an acyl group total degree of substitution, ac represents an acetyl group substitution degree, pr represents a propionyl group substitution degree, bu represents a butyryl group substitution degree, and pen represents a pentanoyl group substitution degree , Hep represents a hexanoyl group substitution degree, bz represents a benzoyl group substitution degree, and oct represents an octanoyl group substitution degree. The composition ratio represents an acrylic resin / cellulose ester resin (mass ratio). Specifically, for example, in Example 2, 98 parts by mass of the above-mentioned acrylic resin and 100 parts by mass of a cellulose ester resin (weight average molecular weight (Mw) 2000000, Example 2 is the same as Example 1 except that 2 parts by mass of propyl group substitution degree: 2.75, acetyl group substitution degree: 0.19, propionyl group substitution degree: 2.56) was used.

In Table 3, BR75 represents an acrylic resin (methyl methacrylate resin: DIANAL BR75 manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight (Mw) 85000), BR64 represents an acrylic resin (methyl methacrylate resin: 259 manufactured by Mitsubishi Rayon Co., Ltd.) and MB-2539 is an acrylic resin (methyl methacrylate resin: DAIANAL MB-2539 manufactured by Mitsubishi Rayon Co., Ltd., weight average Molecular weight (Mw) 80000). A1 represents an acrylic resin (weight average molecular weight (Mw) of 10,000,000) obtained by polymerizing a monomer mixture of methyl methacrylate (MMA) and methacrylic acid (MA) in a mass ratio of 98: 2, A2 represents methacrylic acid (Weight average molecular weight (Mw) of 1100000) obtained by polymerizing a monomer mixture of methyl (MMA) and methacrylic acid (MA) in a mass ratio of 97: 3.

(Comparative Example 2)

The same as in Example 4 except that no silane coupling agent was contained in the dope.

(Comparative Example 3)

Except that the acrylic resin is not contained in the dope.

Table 3 summarizes the doping compositions in Examples 2 to 25 and Comparative Examples 2 and 3.

The resin film obtained as described above was evaluated by the following evaluation method in addition to the above evaluation.

(Elongation cracking)

First, the obtained resin film was stretched at an elongation of 40%. The surface of the stretched resin film was visually confirmed. When the surface can be confirmed to be smooth, it is evaluated as "? &Quot;, and the smoothness of the surface is somewhat lowered. If the surface can not confirm the crack, it is evaluated as " If it is not confirmed in the central part, it is evaluated as " DELTA ", and when the surface crack is completely confirmed, it is evaluated as "X ".

(Brittle: ductile fracture)

First, a test piece having a size of 100 mm x 10 mm was cut from the obtained resin film. The cut test specimens were folded inward and outward once so as to form a line in the longitudinal center of the specimen so as to confirm whether or not the folded test specimen was cracked. This operation was performed three times. Also, dividing here indicates that the test body is divided into two parts.

As a result, it was evaluated as "o" if it was not cracked once, and "x" From this evaluation, the brittleness of the optical film can be evaluated.

The evaluation results are shown in Table 4.

As can be seen from Tables 3 and 4, even when an acrylic resin and a cellulose ester resin are used in combination as a transparent resin, a resin film containing an acrylic resin, silica particles and an organic silicon compound 25), compared with the resin film containing no organosilicon compound (Comparative Example 2) or the resin film containing no acrylic resin (Comparative Example 3), the dropout of the silica particles was suppressed even when stretched, . From this, it was found that by containing an acrylic resin, silica particles and an organic silicon compound, not only the moisture resistance and the heat resistance were excellent, but also the occurrence of problems at the time of drawing was sufficiently suppressed. It was also found that the resin film containing no acrylic resin (Comparative Example 3) not only lowered the moisture resistance but also the effect of inhibiting the occurrence of problems at the time of drawing, as compared with Examples 2 to 25.

Further, when the content ratio of the acrylic resin and the cellulose ester resin in the mass ratio of 95: 5 to 30:70 (Examples 3 to 6) was excellent, the heat resistance and the moisture resistance were excellent, (Example 2 or Example 7) as well as suppressing the occurrence of cracks at the time of elongation, and having excellent ductility and excellent processability.

When the total degree of substitution (T) of the acyl group is 2 to 3 and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3 in the cellulose ester resin (Examples 8 to 13, And Example 15) are excellent in heat resistance and moisture resistance, and can sufficiently suppress the occurrence of problems at the time of stretching. In addition, in the case of containing other cellulose ester resins (Example 14, Example 16, and Example 17 ), The occurrence of cracks during stretching was suppressed, and the excellent ductility and processability were excellent.

Further, when a cellulose ester resin having a weight average molecular weight of 75000 to 350000 was contained (Examples 19 and 20), heat resistance and moisture resistance were excellent, and the occurrence of problems during stretching was sufficiently suppressed As compared with the case where a cellulose ester-based resin having a weight average molecular weight outside the above-described range (Example 18 and Example 21) was contained.

Further, when an acrylic resin having a weight average molecular weight of 70,000 to 1,000,000 (Example 23 and Example 24) is contained, it is excellent in heat resistance and moisture resistance and can sufficiently suppress the occurrence of problems at the time of stretching (Example 22 and Example 25) containing an acrylic resin having a weight average molecular weight outside the above-described range.

[Example C]

Next, the kinds of organosilicon compounds were examined.

(Example 26)

The same as Example 4 except that KBM603 [(CH ₃ O) ₃ SiC ₃ H ₆ NHC ₂ H ₄ NH ₂ , refractive index 1.44] manufactured by Shin-Etsu Chemical Co., Ltd. was used as the organic silicon compound.

(Example 27)

The same as Example 4 except that Z-6047 [Ph ₂ Si (OCH ₃ ) ₂ , refractive index 1.54] manufactured by Toray Dow Corning Toray Co., Ltd. was used as the organic silicon compound.

(Example 28)

As the organosilicon compound, Z-6940 [(C ₂ H ₅ O) ₃ SiC ₃ H ₅ -S ₄ -C ₃ H ₅ Si (OC ₂ H ₅ ) ₃ , refractive index 1.49] manufactured by Toray Dow Corning Toray Co., Is used as in the fourth embodiment.

(Example 29)

The same as Example 4 except that KBM573 [(CH ₃ O) ₃ SiC ₃ H ₆ NHPh, refractive index 1.5] manufactured by Shin-Etsu Chemical Co., Ltd. was used as the organic silicon compound.

The resin film obtained as described above was evaluated by the following evaluation method in addition to the above evaluation.

(Hayes)

First, the haze of the obtained resin film was measured in accordance with JIS K7136. Specifically, the haze of the obtained resin film was measured using a haze meter (NDH2000 type, manufactured by Nippon Denshoku Kogyo K.K.). When the measured haze is less than 0.5%, it is evaluated as " ", and when the measured haze is less than 1.5%, it is evaluated as & .

The evaluation results are shown in Table 5.

From Table 5, it was found that when the organosilicon compound having a refractive index of 1.45 to 1.5 (Example 4, Example 28, and Example 29) was used, the heat resistance, moisture resistance, and workability were excellent, (Examples 26 and 27), the haze was low and transparency was excellent, as compared with the case where the refractive index was outside the above range (Example 26 and Example 27).

[Example D]

Finally, the case of containing acrylic particles was studied.

(Example 30)

Except that 0.3 part by mass of acrylic particles having a volume average particle diameter of 0.1 占 퐉 was contained in 100 parts by mass of the transparent resin.

(Example 31)

Except that 50 parts by mass of acrylic particles having a volume average particle diameter of 0.1 占 퐉 were contained in 100 parts by mass of the transparent resin in the dope.

(Example 32)

Except that 0.5 part by mass of acrylic particles having a volume average particle diameter of 0.1 占 퐉 was contained in 100 parts by mass of the transparent resin.

(Example 33)

The procedure of Example 4 was repeated except that 10 parts by mass of acrylic particles having a volume average particle diameter of 0.1 占 퐉 was contained in 100 parts by mass of the transparent resin.

(Example 34)

Except that 20 parts by mass of acrylic particles having a volume average particle diameter of 0.1 占 퐉 were contained in 100 parts by mass of the transparent resin.

(Example 35)

Except that 20 parts by mass of acrylic particles having a volume average particle size of 0.5 占 퐉 were contained in 100 parts by mass of the transparent resin.

(Example 36)

Except that 20 parts by mass of acrylic particles having a volume average particle diameter of 1 占 퐉 were contained in 100 parts by mass of the transparent resin in the dope.

(Example 37)

Except that 20 parts by mass of acrylic particles having a volume average particle diameter of 2 占 퐉 was contained in 100 parts by mass of the transparent resin.

The resin film obtained as described above was evaluated by the following evaluation method in addition to the above evaluation.

(Processability: cuttability)

The resulting resin film was ruptured using a light load tearing tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the rupture surface and the like were visually confirmed. If the rupture surface is very smooth and ruptured straight, it is evaluated as " o ", and if it is ruptured, it is evaluated as " .

(chip)

The resin film thus obtained was ruptured 10 times on the adhesive sheet in the light load tearing test machine. Thereafter, the number of chips adhered on the adhesive sheet was counted. Then, the number of chips was calculated as the number per 1 m ² (the number per unit area), and the following evaluation was made based on the calculation results. When the number per unit area is less than 10, it is evaluated as "", and when it is less than 30, it is evaluated as""

The evaluation results are shown in Table 6.

As can be seen from Table 6, even if acrylic-based particles are contained, when the acrylic-based resin, silica particles and organic silicon compound are contained, moisture resistance and heat resistance are excellent and occurrence of problems during drawing can be sufficiently suppressed . It was also found that the inclusion of the acrylic particles suppressed the cutting property and the generation of chips. It was also found that the effect had an effect on the particle size and content of the acrylic particles.

1: Doping kiln
2: Doped liquid pump
3: DOPE POLICE CHAMBER
4: Filter
6: Exhaust valve
7: Piping
11: Manufacturing apparatus of resin film
12: endless belt support
13: Flexible die
14: peeling roller
15: Stretching device
17: Drying device
18: retractor
19: Dof
21:
22: Filtration device
23:

Claims (23)

Acrylic resin,
Silica particles,
A silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate, wherein the silane coupling agent is a compound represented by the following formula (2) .
(2)

(Wherein R ³ represents an alkylene group, OR ⁴ represents an alkoxy group, p represents 1 to 5, and q represents 1 to 3) delete delete delete The method according to claim 1,
A resin film further comprising a cellulose ester-based resin. 6. The method according to claim 1 or 5,
A silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensate of the hydrolyzate, and the refractive index of the resin film is 1.45 to 1.5. 6. The method according to claim 1 or 5,
A resin film further comprising acrylic particles. 6. The method according to claim 1 or 5,
Wherein the stretching ratio is 10 to 200% as determined by the following equation (1) in at least one direction.
&Quot; (1) "
Elongation (%) = {(length after stretching - length before stretching) / length before stretching} x 100 A softening step of forming a flexible film by being softened on a support on which a resin solution containing an acrylic resin, silica particles and a silane coupling agent runs,
A peeling step of peeling the flexible film as a film from the support,
And a stretching step of stretching the peeled film in a direction perpendicular to the transport direction of the film. A polarizing element; and a transparent protective film disposed on at least one surface of the polarizing element,
Wherein the transparent protective film is the resin film of any one of claims 1 to 5. A liquid crystal cell,
And two polarizing plates arranged so as to sandwich the liquid crystal cell,
Wherein at least one of the two polarizing plates is the polarizing plate of claim 10. 10. The method of claim 9,
Wherein the silane coupling agent is a compound represented by the following formula (1).
≪ Formula 1 >

(In formula 1, Y represents a reactive organic functional group, R ¹ represents an alkyl group, OR ² is an alkoxy group, m represents 1 or 2, n represents 0 or 1, m + n is from 1 to 3 Lt; / RTI > 13. The method of claim 12,
Wherein the reactive organic functional group is a functional group containing at least one of an amino group and a phenyl group. 10. The method of claim 9,
Wherein the silane coupling agent is a compound represented by the following formula (2).
(2)

(Wherein R ³ represents an alkylene group, OR ⁴ represents an alkoxy group, p represents 1 to 5, and q represents 1 to 3) 15. The method according to any one of claims 9 to 13,
Wherein the resin film further comprises a cellulose ester-based resin. 15. The method according to any one of claims 9 to 13,
A silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensate of the hydrolyzate, wherein the refractive index of the resin film is 1.45 to 1.5. 15. The method according to any one of claims 9 to 13,
Wherein the resin film further comprises acrylic particles. 15. The method according to any one of claims 9 to 13,
Wherein the stretching step is stretched in at least one direction so that an elongation determined by the following formula (1) is 10 to 200%.
&Quot; (1) "
Elongation (%) = {(length after stretching - length before stretching) / length before stretching} x 100 An acrylic resin; Silica particles; A softening step of forming a flexible film on a support on which a resin solution containing at least one member selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent and a polycondensate of the hydrolyzate is run,
A peeling step of peeling the flexible film as a film from the support,
And a stretching step of stretching the peeled film in a direction perpendicular to the transport direction of the film. 20. The method of claim 19,
Wherein the resin film further comprises a cellulose ester-based resin. 21. The method according to claim 19 or 20,
A silane coupling agent, a hydrolyzate of the silane coupling agent, and a polycondensate of the hydrolyzate, wherein the refractive index of the resin film is 1.45 to 1.5. 21. The method according to claim 19 or 20,
Wherein the resin film further comprises acrylic particles. 21. The method according to claim 19 or 20,
Wherein the stretching step is stretched in at least one direction so that an elongation determined by the following formula (1) is 10 to 200%.
&Quot; (1) "
Elongation (%) = {(length after stretching - length before stretching) / length before stretching} x 100

Images