TW201540510A - Multilayered film and method for manufacturing same - Google Patents

Abstract

A multilayered film provided with a base film and a resin layer containing particles provided on the base film, wherein the resin layer has a plurality of projections on the surface on the opposite side of the base film such that the value (G) expressed by G=NA/NF fulfills the relation 3.5 ≤ G ≤ 7, and NB ≥ NC ≥ ND ≥ NE ≥ NF, where (a) the number of 5-nm-high projections per square millimeter is defined as NA/mm2, (b) the number of 10-nm-high projections per square millimeter is defined as NB/mm2, (c) the number of 15-nm-high projections per square millimeter is defined as NC/mm2, (d) the number of 20-nm-high projections per square millimeter is defined as ND/mm2, (e) the number of 25-nm-high projections per square millimeter is defined as NE/mm2, and (f) the number of 30-nm-high projections per square millimeter is defined as NF/mm2.

Description

Complex layer film and method of manufacturing same

The present invention relates to a plurality of layers of film and a method of manufacturing the same.

Conventionally, a plurality of layers of a plurality of layers have been known (see Patent Documents 1 and 2). Since such a plurality of layers of films can achieve various functions by combining the characteristics of the respective layers, they are used in a wide range of applications. For example, in the case of an optical film used in various image display devices such as a liquid crystal display device, an organic EL display device, and a plasma display device, a plurality of thin films are used.

From the viewpoint of improving the production efficiency, the plurality of thin film as described above is mostly manufactured in the form of a long film. Further, such a plurality of long film layers are usually wound into a film roll and stored and transported in the state of the film roll.

Moreover, a technique such as Patent Document 3 is known.

Prior technical literature

Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-79664

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-264643

[Patent Document 3] Japanese Patent Laid-Open No. Hei 8-73623

A film roll produced by winding up a plurality of thin film layers has a convex defect called a "pitting point" having a width of about 1 mm to 3 mm. When the above-mentioned convex defect is transferred to a plurality of layers of film, the film of the plurality of layers to be transferred is deformed and the optical characteristics of the portion are impaired.

Further, since the defect is not generated before the winding of the plurality of layers of the film, but is produced after the film roll is produced, it is difficult to detect it by inspection in the production line of the plurality of layers.

Further, since it is necessary to detect the above defects after the production of the film roll, it is necessary to inspect the plurality of layers of film from the film roll for inspection, and it takes labor to rewind the plurality of films which are taken up again. and time. Therefore, it is difficult to sort the aforementioned defect-free film roll in a state where the film roll is held.

Due to such a situation, it has been required to develop a plurality of layers of films capable of suppressing the occurrence of the aforementioned defects when formed into a film roll.

Further, for example, in an optical film such as a retardation film, it is generally required that the internal haze is small. The case where the internal haze is required to be small is also the same when the optical film is a plurality of layers. Therefore, when a film roll is produced as described above, it is also required to be able to reduce the internal haze in a plurality of layers of film which can suppress the occurrence of convex defects.

The present invention has been made in view of the above-described problems, and an object of the invention is to provide a multilayer film which can suppress the occurrence of the aforementioned convex defects and which can reduce the internal haze when the film roll is wound up, and a method for producing the same.

In order to solve the above problems, the inventors of the present invention have found that a plurality of layers including a base film and a resin layer containing particles have a predetermined degree of regularity on a surface of the resin layer opposite to the base film. In the case of the protrusion, when the plurality of layers of the film are formed into a film roll, the occurrence of convex defects can be suppressed, and the internal haze of the plurality of layers can be reduced, and the present invention has been completed.

That is, the present invention is as follows.

[1] A plurality of layers including a base film and a resin layer containing a particle provided on the base film, wherein the resin layer has a plurality of protrusions on a surface opposite to the base film , among the projections, (a) the number of 5nm protrusion height of 1mm ² to each number N _a / mm ^2, (b) the number of the protrusion height of 10nm to 1mm ² of each of the N _B number / mm ^2, (c) the height of the projections ² of the number of 15nm to 1mm number N _C / mm ^2, (d) the height of each protrusion 20nm number per 1mm ² of the set number N _D / mm ^2, (e) the height of 25nm The number of protrusions per 1 mm ² is set to N _E / mm ² , and (f) the value of G = N _A / N _F when the number of protrusions of height 30 nm is set to N _F / mm ² per 1 mm ² . G is 3.5 ≦ G ≦ 7, and N _B ≧ N _C ≧ N _D ≧ N _E ≧ N _F .

[2] The plurality of layers of the film according to [1], wherein the resin layer contains a polymer, and the polymer contains a polyurethane.

[3] The plurality of layers of the film according to [1] or [2], wherein the particles comprise a plurality of particles having different average particle diameters.

[4] The plurality of layers of the film according to [3], wherein the particles comprise: particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle of 150 nm or more.

[5] The plurality of layers of the film according to [1], wherein the resin layer contains a polymerization The particles include: particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle diameter of 150 nm or more; and the particles (S) in the resin layer with respect to 100 parts by weight of the polymer The amount is 2 parts by weight or more and 24 parts by weight or less.

[6] The plurality of layers of the film according to [1], wherein the resin layer contains a polymer; the particles comprise: particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle size of 150 nm or more; The amount of the particles (L) in the resin layer is 5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the polymer.

[7] The multi-layer film according to any one of [1] to [6] wherein the particles are cerium oxide.

[8] The multi-layer film according to any one of [1] to [7] wherein the thickness of the resin layer is 10 nm or more and 100 nm or less.

[9] The plurality of layers of the film according to any one of [1] to [8], wherein the plurality of layers of the film are phase difference films.

[10] The plurality of layers of the film according to any one of [1] to [8], wherein the plurality of layers of the film are polarizing plate protective films.

[11] A method for producing a plurality of layers of a film according to any one of [1] to [10], comprising the steps of: polymerizing a plurality of particles having different average particle diameters and polymerizing Mixing the materials to obtain a fluid-like resin; coating the fluid-like resin on the substrate film to form the resin a step of forming a film; and a step of curing and/or drying the film of the resin formed on the substrate film to obtain a resin layer.

[12] The method for producing a multilayer film according to [11], wherein the particles comprise particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle diameter of 150 nm or more.

The multi-layer film of the present invention can suppress the occurrence of convex defects and can reduce the internal haze when it is wound up to form a film roll.

According to the method for producing a plurality of layers of the film of the present invention, it is possible to produce a plurality of layers of film which can suppress the occurrence of convex defects and which can reduce the internal haze when being wound up to form a film roll.

100‧‧‧Multilayer film

110‧‧‧Substrate film

111‧‧‧The surface of the base film opposite to the resin layer

120‧‧‧ resin layer

121‧‧‧Face of the resin layer opposite to the substrate film

122‧‧‧ Protrusion

200‧‧‧film roll

210‧‧‧ wrinkles

220‧‧‧Winding shaft

230‧‧‧ recessed

Fig. 1 is a cross-sectional view schematically showing an example of a plurality of layers of a film according to an embodiment of the present invention.

Fig. 2 is a front view schematically showing an example of the appearance of wrinkles caused by the fixation of the film in the prior film roll.

Fig. 3 is an example of a multi-layer film satisfying the requirements of 3.5 ≦ G ≦ 7 and N _B ≧ N _C ≧ N _D ≧ N _E ≧ N _F , and the height of the protrusion is used as the horizontal axis and the number of protrusions. The distribution of the vertical axis.

Form for implementing the invention

Hereinafter, the present embodiment and examples will be described to explain the present invention in detail. Bright. However, the present invention is not limited by the embodiments and the examples disclosed below, and can be arbitrarily changed without departing from the scope of the invention and the scope of the invention.

In the following description, the "(meth)acrylonitrile group" includes both an acrylonitrile group and a methacryl group. Further, "(meth) acrylate" includes both acrylate and methacrylate.

In the following description, the "(co)polymer" includes both a polymer and a copolymer.

In the following description, the average particle diameter of the particles is determined by measuring the particle size distribution by the laser diffraction method without any prior notification, and the calculated particle size distribution is calculated from the small diameter side. The volume becomes 50% of the particle size.

In the following description, the hysteresis value Re of the in-plane direction of the film is a value represented by Re = (nx - ny) × d unless otherwise notified. Further, the hysteresis value Rth in the thickness direction of the film is a value represented by Rth = {(nx + ny)/2 - nz) × d. Here, nx means a refractive index in a direction in which a maximum refractive index is provided in a direction perpendicular to the thickness direction of the film (in-plane direction), and ny means that the direction of nx is perpendicular to the in-plane direction of the film. The refractive index of the direction. The nz line indicates the refractive index in the thickness direction of the film. d is the film thickness of the film. The measurement wavelength of the aforementioned hysteresis value is 550 nm unless otherwise notified in advance. The hysteresis value described above can be measured using a commercially available phase difference measuring device (for example, "KOBRA-21ADH" manufactured by Oji Scientific Instruments Co., Ltd.) or the Senarmont method.

Moreover, the "polarizing plate" is not only a rigid member but also a flexible member such as a resin film.

[1. Outline of a plurality of layers of film]

Fig. 1 is a cross-sectional view schematically showing an example of a plurality of layers of a film 100 according to an embodiment of the present invention.

As shown in Fig. 1, a plurality of layers of film 100 according to an embodiment of the present invention includes a base film 110 and a resin-containing resin layer 120 provided on the base film 110. Further, the resin layer 120 described above has a plurality of protrusions 122 on the surface 121 opposite to the base film 110. In Fig. 1, the symbol "T" indicates the thickness of the resin layer 120, and the symbol "H" indicates the height of the protrusion 122. As shown in Fig. 1, the thickness T of the resin layer 120 indicates the thickness of the region of the resin layer 120 where the protrusions 122 are absent.

In the plurality of layers of the film 100, the protrusions 122 of the surface 121 of the resin layer 120 satisfy 3.5 ≦ G ≦ 7 and N _B ≧ N _C ≧ N _D ≧ N _E ≧ N _F .

Here, the aforementioned value G is a value represented by G = N _A / N _F .

Further, N _A , N _B , N _C , N _D , N _E and N _F represent the following numbers.

(a) N _A (unit: unit/mm ² ) indicates the number of protrusions having a height of 5 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

(b) N _B (unit: unit/mm ² ) indicates the number of protrusions having a height of 10 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

(c) N _C (unit: unit/mm ² ) indicates the number of protrusions having a height of 15 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

(d) N _D (unit: unit/mm ² ) indicates the number of protrusions having a height of 20 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

(e) N _E (unit: unit/mm ² ) indicates the number of protrusions having a height of 25 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

(f) N _F (unit: unit/mm ² ) indicates the number of protrusions having a height of 30 nm per 1 mm ² among the protrusions 122 of the surface 121 of the resin layer 120 on the side opposite to the base film 110.

Here, among the values of the height of the protrusions, the height of 5 nm is expressed by an effective number, and is 4.5 nm or more and 5.4 nm or less. In the same manner, when the effective number is used, the height of 10 nm means 9.5 nm or more and 10.4 nm or less, the height of 15 nm means 14.5 nm or more and 15.4 nm or less, and the height of 20 nm means 19.5 nm or more and 20.4 nm or less, and the height is 25 nm. It is 24.5 nm or more and 25.4 nm or less, and the height 30 nm shows 29.5 nm or more and 30.4 nm or less.

With such a configuration, when the plurality of layers of the film 100 are wound up to form a film roll, it is possible to suppress the occurrence of convex defects and to reduce the internal haze.

(1) For the suppression of convex defects:

The reason why the plurality of layers of the film of the present invention can suppress the occurrence of convex defects is not necessarily clear, but it is presumed as follows based on the study of the present inventors. However, the invention is not limited by the speculations set forth below.

When the film is wound up to produce a film roll, the film which is overlapped and rolled up is partially fixed. In such a fixed part, the position of the film Move is restricted. Therefore, the tension supplied to the film at the time of winding is not dispersed to the entire film, and a stress deviation occurs in the film. Such a stress deviation is caused by wrinkles in the film roll.

Fig. 2 is a front view schematically showing an example of the appearance of the wrinkles 210 caused by the fixation of the film in the prior film roll 200. As shown in Fig. 2, when the film is taken up on the take-up shaft 220 to form the film roll 200, the aforementioned wrinkles 210 are generally formed into a polygonal shape. Specifically, a plurality of polygonal shapes (usually rhombic) recesses 230 are formed in the axial direction and the circumferential direction of the film roll 200, and wrinkles 210 are mostly formed at positions corresponding to the sides of the polygonal shape of the concave portion 230. .

Such a wrinkle 210 is produced in a manner that does not significantly bend the film at the beginning. However, when the film roll is stored and stored, the degree of recession (depth) of the polygonal recess 230 is gradually increased due to the weight of the film itself. Further, when the degree of depression of the concave portion 230 is increased, the degree of bending of the film is increased in the portion where the wrinkles 210 are generated. When the film is greatly bent beyond the elastic limit of the film, it is considered that the film is plastically deformed at the bent portion thereof, and a convex defect called "pitting" occurs.

On the other hand, as shown in Fig. 1, a plurality of thin films 100 having a plurality of protrusions 122 satisfying the above-described requirements are provided on the surface 121 of the resin layer 120 opposite to the base film 110, and the surface 121 is excellent. Slippery. The surface 121 of the resin layer 120 opposite to the base film 110 is usually the outermost surface of the plurality of layers of the film 100, and the surface 121 has excellent slipperiness, and can be suppressed when the plurality of layers of the film 100 are wound up. The affixing of the multi-layer film 100 that is rolled up is overlapped. Therefore, it is presumed that since wrinkles in the film roll can be suppressed, Therefore, it is possible to suppress the occurrence of convex defects caused by the wrinkles.

(2) For internal haze:

As a method for improving the smoothness of the film surface as described above, for example, it is conceivable to provide a projection on the surface thereof to increase the roughness of the surface. However, in the case where the height of the protrusion is high, the optical haze such as reflection and refraction of the surface on which the protrusion is provided causes the surface haze to greatly increase, and it is difficult to obtain an optical film. Therefore, the inventors of the present invention have studied the provision of a projection having a low surface haze and a low surface on the film surface.

Further, the above resin layer is formed as a resin layer containing particles. In general, the resin layer containing particles is in a state in which the internal haze of the resin layer greatly increases in accordance with the amount and size of the particles. Therefore, from the viewpoint of being suitable for an optical film, the resin layer is preferably designed in such a manner as to reduce the internal haze. In general, in order to avoid an increase in the internal haze, it is preferable that the particles are small, and in order to prevent the internal haze from rising and the occurrence of optical defects due to the incorporation of large particles, it is preferable to use particles having the same size.

Therefore, the inventors of the present invention attempted to provide a resin layer containing particles having a small volume and a uniform particle diameter on the base film, and to provide protrusions having a low height on the film surface. However, the film obtained in this manner has a small slip property on the surface having the protrusions, and it is difficult to suppress the occurrence of convex defects in the film roll.

Therefore, the inventors intend to increase the volume of the particles to increase the height of the protrusions, and to improve the slipperiness of the surface on which the protrusions are provided. Therefore, the inventors of the present invention conducted the same research as described above in order to increase the height of the protrusions and increase the volume of the particles. However, even if the height of the projections is increased, the slip property is not sufficiently improved, and it is difficult to suppress the occurrence of convex defects in the film roll.

Further, if the number of protrusions is increased, it is considered that the slipperiness of the surface having the protrusions may be improved. However, increasing the number of protrusions requires an increase in the number of particles. The number of particles is too large, and there is a possibility that the internal haze rises due to reflection and refraction inside the resin layer.

On the other hand, the plurality of layers of the film 100 shown in Fig. 1 are provided on the surface 121 of the resin layer 120 opposite to the base film 110, and are provided to satisfy 3.5 ≦ G ≦ 7 and N _B ≧ N _C ≧ N _D ≧ A protrusion 122 of the necessary condition of N _E ≧N _F . The necessary conditions (3.5≦G≦7 and N _B ≧N _C ≧N _D ≧N _E ≧N _F ) are for the protrusions 122 which do not cause the degree of surface haze rise to be low, indicating that the height distribution of the protrusions 122 is wide. And the number of high protrusions is small compared to the number of low protrusions. For an example of the plurality of layers of the film 100 satisfying the necessary conditions, a map in which the height of the protrusions 122 is used as the horizontal axis and the number of the protrusions 122 as the vertical axis is shown in FIG. In the above-mentioned necessary condition, in the profile of the third figure in which the height of the protrusion 122 is the horizontal axis and the number of the protrusions 122 as the vertical axis, the width of the peak is wide and gentle, and the apex of the peak is desired. Small range. The face 121 of the protrusions 122 having such different heights has a significantly high slipperiness. Conventionally, in a projection capable of suppressing a low degree of surface haze, it is not considered that the slip of the surface having the projection can be adjusted by adjusting the distribution of the projection. As far as the prior art is concerned, it is possible to adjust the slipperiness of the surface having the protrusion by adjusting the distribution of the protrusion height as described above, which is an unexpected effect.

Further, a resin layer having protrusions satisfying the above-mentioned requirements (3.5 ≦ G ≦ 7 and N _B ≧ N _C ≧ N _D ≧ N _E ≧ N _F ) is used by appropriately combining small particles and large particles. , made with a small amount of particles. Since the amount of particles can be reduced, the internal haze caused by the resin layer can be prevented from rising.

Therefore, even in the case where the protrusions are formed by the particles contained in the resin layer, the complex film of the present invention does not cause an increase in the internal haze, and the occurrence of convex defects in the film roll can be suppressed. The particles used in the optical film have been considered to have a smaller volume from the viewpoint of not impairing the characteristics of the optical film, and the particle size is more uniform. As described above, the use of a combination of small particles and large particles as described above provides a resin layer having a small internal haze and excellent surface slip properties, which is an unexpected effect.

[2. Substrate film]

As the base film, a film made of a resin is usually used. As the resin constituting the base film, a resin containing any polymer can be used. In particular, as the resin constituting the base film, a thermoplastic resin is preferred, and an alicyclic olefin resin is particularly preferred. The alicyclic olefin resin is a resin containing an alicyclic olefin polymer, and is suitable for an optical film because of its excellent transparency, low hygroscopicity, dimensional stability, and light weight.

Further, the base film may be a film having a single layer structure of only one layer, or may be a film having a plurality of layers of two or more layers. When the base film has a plurality of layers, it is preferable that one or more layers of the base film are composed of an alicyclic olefin resin.

The alicyclic olefin polymer is a polymer having an alicyclic structure in a structural unit of a polymer, and a polymer having an alicyclic structure in a main chain and a polymer having an alicyclic structure in a side chain can be used. Any one. Further, the alicyclic olefin polymer may be used singly or in combination of two or more kinds in any ratio. In particular, from the viewpoint of mechanical strength, heat resistance and the like, a polymer having an alicyclic structure in its main chain is preferred.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure, an unsaturated hycyclic hydrocarbon (cycloalkenene, cycloalkyne) structure, and the like. In particular, from the viewpoint of mechanical strength, heat resistance, and the like, a naphthene structure and a cycloolefin structure are preferable, and a naphthene structure is particularly preferable.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, preferably 5 or more, and preferably 30 or less, preferably 20 or less, and particularly preferably 15 or less. The following range. Thereby, the mechanical strength, heat resistance, and moldability of the base film can be highly balanced, which is preferable.

The ratio of the structural unit having an alicyclic structure in the alicyclic olefin polymer can be appropriately selected depending on the purpose of use, and is preferably 55 wt% or more, more preferably 70 wt% or more, and particularly preferably 90 wt% or more. . When the ratio of the structural unit having an alicyclic structure in the alicyclic olefin polymer is in this range, it is preferable from the viewpoint of transparency and heat resistance of the base film.

Examples of the alicyclic olefin polymer include a norbornene polymer, a monocyclic cyclic olefin polymer, a cyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer, and the like. Things and so on. Among these, the norbornene polymer is preferred because it has good transparency and formability.

Examples of the norbornene polymer include a ring-opening polymer having a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and any monomer, or the like. An addition polymer of a monomer having a norbornene structure, or an addition copolymer of a monomer having a norbornene structure and an arbitrary monomer, or a hydride or the like. Among these, a hydride of a ring-opening polymer having a monomer having a norbornene structure is used from the viewpoints of transparency, moldability, heat resistance, low moisture absorption, dimensional stability, and lightness. And have The hydride of the ring-opening copolymer of the norbornene-structured monomer is particularly preferred.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and tricyclo [4.3.0.1 ^{2, 5} ] 癸 -3, 7- Diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 ^2,5 ]non-3-ene (common name: methylenetetrahydroanthracene), tetracyclic [4.3 .0.1 ^2,5 .1 ^7,10 ]Dodec-3-ene (common name: tetracyclododecene), and derivatives of such compounds (for example, those having a substituent in the ring) and the like. Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Further, the substituents may be the same or different, and a plurality of rings may be bonded. Further, the monomer having a norbornene structure may be used alone or in combination of two or more kinds in any ratio.

Examples of the type of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a ruthenium atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a stanol group, a decyl group, an amine group, a nitrile group, and a sulfonic acid group.

Examples of the monomer which can be subjected to ring-opening copolymerization with a monomer having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene, and derivatives thereof; A cyclic conjugated diene such as hexadiene or cycloheptadiene or a derivative thereof. The monomer having a norbornene structure and any monomer capable of ring-opening copolymerization may be used alone or in combination of two or more types in any ratio.

A ring-opening polymer having a monomer of a norbornene structure, and a ring-opening copolymer of a monomer having a norbornene structure and any monomer capable of ring-opening copolymerization, for example, by using a monomer in a conventional In the presence of a ring-opening polymerization catalyst, It is produced by polymerization or copolymerization.

Examples of the monomer which can be subjected to addition copolymerization with a monomer having a norbornene structure include, for example, an α-olefin having 2 to 20 carbon atoms such as ethylene, propylene or 1-butene, and the like. a cycloolefin such as cyclobutene, cyclopentene or cyclohexene and the like; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1 a non-conjugated diene such as 4-hexadiene. Among these, α-olefin is preferred, and ethylene is preferred. In addition, any monomer which can be subjected to addition copolymerization with a monomer having a norbornene structure may be used alone or in combination of two or more kinds in any ratio.

An addition polymer of a monomer having a norbornene structure, and an addition copolymer of a monomer having a norbornene structure and any monomer capable of copolymerization, for example, by a conventional addition of a monomer It is produced by carrying out polymerization or copolymerization in the presence of a polymerization catalyst.

The cyclic olefin polymer which is a monocyclic ring may, for example, be an addition polymer of a cyclic olefin monomer having a single ring such as cyclohexene, cycloheptene or cyclooctene.

The bulk conjugated diene polymer may, for example, be a polymerization obtained by cyclizing an addition polymer of a conjugated diene monomer such as 1,3-butadiene, isoprene or chloroprene. a 1,2- or 1,4-addition polymer of a cyclic conjugated diene monomer such as cyclopentadiene or cyclohexadiene; and such a hydride or the like.

Examples of the vinyl alicyclic hydrocarbon polymer include a polymer of a vinyl alicyclic hydrocarbon monomer such as vinylcyclohexene or vinylcyclohexane, and a hydrogenated product thereof; styrene, α-A a hydrogenated product obtained by partially hydrogenating an aromatic ring contained in a polymer obtained by polymerizing a vinyl aromatic hydrocarbon monomer such as styrene; a vinyl alicyclic hydrocarbon monomer or a vinyl aromatic hydrocarbon monomer; With such ethylene A hydrogenated product of an aromatic ring of a copolymer such as a random copolymer or a block copolymer in which a monomer-based aromatic hydrocarbon monomer is copolymerized. Examples of the block copolymer include a diblock copolymer, a triblock copolymer or a multi-block copolymer thereof, and an oblique block copolymer.

The weight average molecular weight (Mw) of the polymer contained in the resin constituting the base film is usually 10,000 or more, preferably 15,000 or more, preferably 20,000 or more, usually 100,000 or less, and preferably 80,000 or less. It is 50,000 or less. Here, the aforementioned weight average molecular weight is a polyisoprene or polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography using cyclohexane as a solvent. However, in the case where the sample is insoluble in cyclohexane, toluene may also be used as a solvent for the aforementioned gel permeation chromatography. When the weight average molecular weight is in such a range, the mechanical strength and the moldability of the plurality of layers of the film can be highly balanced, which is preferable.

The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polymer contained in the resin constituting the base film is usually 1.2 or more, preferably 1.5 or more, more preferably 1.8 or more, and usually 3.5 or less, preferably 3.0 or less, more preferably 2.7 or less. By setting the molecular weight distribution to the lower limit or more of the above range, the productivity of the polymer can be improved and the cost can be suppressed. Further, by setting it to the upper limit or less, since the low molecular weight component can be reduced, the relaxation time can be increased. Therefore, it is possible to suppress slack at the time of high-temperature exposure and to improve the stability of the base film.

The absolute value of the photoelastic modulus C of the polymer contained in the resin constituting the base film is preferably 10 × 10 ^-12 Pa ^-1 or less, more preferably 7 × 10 ^-12 Pa ^-1 or less. 4×10 ^-12 Pa ^-1 or less is particularly good. The photoelastic modulus C is a value represented by "C=Δn/σ" when the birefringence is Δn and the stress is σ. By setting the photoelastic modulus of the polymer within the above range, the variation in the hysteresis value Re in the in-plane direction of the base film can be reduced.

The saturated water absorption of the polymer contained in the resin constituting the base film is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, and particularly preferably 0.01% by weight or less. When the saturated water absorption ratio is in the above range, the hysteresis value in the in-plane direction of the base film and the time-dependent change in the hysteresis value in the thickness direction can be reduced. Moreover, deterioration of the polarizing plate and the image display device having the plurality of layers of the film of the present invention can be suppressed, and the display of the display can be stabilized for a long period of time and can be favorably maintained.

The saturated water absorption rate is a value obtained by immersing the test piece in water at a certain temperature for a certain period of time and increasing the mass with respect to the mass of the test piece before the immersion. The test piece was usually measured by immersing it in water at 23 ° C for 24 hours. The saturated water absorption in the polymer can be adjusted to the aforementioned range, for example, by reducing the amount of polar groups in the polymer. Therefore, from the viewpoint of further reducing the saturated water absorption rate, it is preferred that the polymer contained in the resin constituting the base film has no polar group.

The resin constituting the base film may contain any component in addition to the polymer as long as the effect of the present invention is not significantly impaired. Examples of the optional component include a coloring agent such as a pigment or a dye; a plasticizer; a fluorescent whitening agent; a dispersing agent; a thermal stabilizer; a light stabilizer; an ultraviolet absorber; an antistatic agent; Additives such as slip agents; surfactants. These components may be used alone or in combination of two or more kinds in any ratio.

However, when an alicyclic olefin resin is used as the resin constituting the base film, the alicyclic olefin resin is preferably substantially free of particles. here, The fact that the particles are not contained in the resin means that even if the particles are contained in the resin, the amount of increase in the haze of the base film to a range of 0.05% or less is acceptable from the state in which the particles are not contained at all. The alicyclic olefin polymer tends to have a lack of affinity with most of the organic particles and inorganic particles. Therefore, when the alicyclic olefin resin containing particles is extended, voids are easily generated. However, by reducing the amount of particles as described above, it is possible to suppress the occurrence of voids after stretching and to prevent the haze from becoming large.

The amount of the polymer and the additive contained in the resin constituting the base film can be arbitrarily set in a range in which optical characteristics required for the film of the plurality of layers of the present invention can be exhibited. For example, the ratio of the polymer of the resin constituting the base film is usually 50 to 100% or 70 to 100%. In particular, in the case where an alicyclic olefin resin is used as the resin constituting the base film, the ratio of the polymer contained in the alicyclic olefin resin is usually 80 to 100%, preferably 90% to 100%.

As described above, the base film may be a film having a single layer structure of one layer, or may be a film having a plurality of layers of two or more layers. The multilayer film of the present invention can be used as an optical film having various characteristics by providing the base film as a film having a plurality of layers.

When the base film has two or more layers, it may have two or more layers, or may have two or more layers, and the base film may be in addition to the alicyclic olefin resin. A layer composed of a resin is provided. Examples of the layer composed of the alicyclic olefin resin include a layer having a function of preventing injury, antireflection, antistatic, antiglare, and antifouling.

The average thickness of the base film is preferably 5 μm or more, more preferably 20 μm or more, and most preferably 500 μm or less, and more preferably 300 μm or less.

Further, the thickness variation of the base film is in the longitudinal direction and the width direction, and It is preferred that the average thickness is within 3%. By making the thickness variation into the above range, variation in optical characteristics such as hysteresis value of the base film can be reduced.

The amount of the volatile component containing the base film is preferably 0.1% by weight or less, preferably 0.05% by weight or less, more preferably 0.02% by weight or less. When the amount of the volatile component is within the above range, the dimensional stability is improved, and the hysteresis value in the in-plane direction of the base film and the hysteresis value in the thickness direction are reduced over time. Further, since deterioration of the polarizing plate or the image display device or the like including the plurality of layers of the film of the present invention can be suppressed, the display of the display can be stably and stably held for a long period of time. Here, the volatile component means a substance having a molecular weight of 200 or less. Examples of the volatile component include a residual monomer, a solvent, and the like. The amount of the volatile component, which is set as a total of substances having a molecular weight of 200 or less, can be quantified by analysis using a gas chromatograph.

The method of producing the base film is not limited. The base film can be obtained by molding a resin for forming the base film by any film forming method. Examples of the film forming method include a cast molding method, a extrusion molding method, and a blow molding method. In particular, from the viewpoint of being able to efficiently reduce the amount of residual volatile components, the viewpoint of the global environment and the working environment, and the excellent production efficiency, it is preferable to use a melt extrusion method without using a solvent. As the melt extrusion method, a blow molding method using an extrusion die or the like can be mentioned, and in particular, in terms of excellent productivity and thickness accuracy, a method using a T-die is preferable.

Further, when the base film is provided with two or more layers, the method for producing the base film is not limited. For example, the film layers which are separately formed may be bonded together as needed using an adhesive to produce a base film. The subsequent agent can be formed according to the formation of thin The type of the resin of the film layer is selected as appropriate. Examples of the adhesive include an acrylic adhesive, a urethane adhesive, a polyester adhesive, a polyvinyl alcohol adhesive, a polyolefin adhesive, a modified polyolefin adhesive, and a polyvinyl alkyl ether. Agent, rubber adhesive, ethylene-vinyl acetate adhesive, vinyl chloride-vinyl acetate adhesive, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesive, SIS (styrene-isoprene) Ethylene-styrene block copolymer), ethylene-based adhesive such as ethylene-styrene copolymer, ethylene-(meth)acrylic acid) methyl ester copolymer, ethylene-ethyl (meth)acrylate copolymer, etc. Acrylate adhesive and the like. The following agents may be used alone or in combination of two or more kinds in any ratio. The average thickness of the adhesive layer formed using the adhesive is preferably 0.1 μm or more, preferably 0.5 μm or more, more preferably 10 μm or less, and most preferably 5 μm or less.

When a base film having two or more layers is produced without using an adhesive, for example, a co-extrusion T-die method, a co-extrusion blow molding method, a co-extrusion lamination method, or the like can be used. A method, a film lamination molding method such as dry lamination, or the like.

Further, for example, a base film having two or more layers is produced by applying a coating molding method or the like to a solution containing a resin constituting another thin film layer on the surface of a certain film layer.

Among these, from the viewpoint of production efficiency and the fact that volatile components such as a solvent are not left in the base film, a co-extrusion molding method is preferred. Among the co-extrusion forming methods, the co-extruded T-die method is particularly preferred. Further, in the co-extrusion T-die method, a feed block method and a multi-manifold method can be used, and the thickness variation of each layer can be made small, and the multi-manifold method is more preferable.

The base film may be an unstretched film which is not subjected to the stretching treatment, or may be an extended film after the stretching treatment. Further, in the case where the base film has two or more layers, the film layer which has been subjected to the stretching treatment in advance may be bonded to obtain a stretched film, or the film may be formed of a plurality of layers obtained by co-extrusion or the like. An extension process is performed to obtain an extended film.

The stretching method is not particularly limited, and for example, any of a uniaxial stretching method and a biaxial stretching method can be employed. In the example of the stretching method, an example of the uniaxial stretching method is a method of performing uniaxial stretching in the longitudinal direction by the difference in the peripheral speed of the roll for film transport, and using a tenter stretching machine. A method of performing uniaxial stretching in the width direction. In addition, as an example of the biaxial stretching method, a biaxial stretching method in which the fixing clip is opened and extended in the longitudinal direction while extending in the width direction by the angle of enlargement of the guide rail, and a film transporting method are used. After the difference in the peripheral speed between the rolls, the product is stretched in the longitudinal direction, and the both ends thereof are gripped by a clip, and a sequential biaxial stretching method in which the tenter stretcher is extended in the width direction is used. Further, for example, a tilt extension method may be used which uses a tenter stretching machine in such a manner that a feed force or a tensile force or a traction force of different speeds at right and left can be applied in the width direction or the longitudinal direction, and is not parallel to the width direction of the film. The oblique extension is continuously performed in a direction other than the vertical direction.

Examples of the apparatus used for the extension include a longitudinal uniaxial stretching machine, a tenter stretching machine, a bubble stretcher, a roller stretching machine, and the like. The glass transition temperature of the resin constituting the stretched film is Tg, and the elongation temperature is preferably (Tg-30 ° C) or more, preferably (Tg - 10 ° C) or more, and (Tg + 60 ° C) or less. Preferably, it is (Tg + 50 ° C) or less. The stretching ratio can be appropriately selected in accordance with the optical characteristics of the substrate film to be used. Specific extension The rate is usually 1.05 times or more, preferably 1.1 times or more, usually 10.0 times or less, preferably 2.0 times or less.

[3. Resin layer]

The resin layer is a layer provided on the base film, and has a projection on a surface opposite to the base film. The protrusion has a value G of G=N _A /N _F , and is usually 3.5 or more, preferably 3.6 or more, preferably 4.0 or more, more preferably 4.5 or more, and usually 7.0 or less, and preferably 6.4 or less. It is preferably 6.0 or less, more preferably 5.5 or less. When the value G is larger than zero, it means that the surface 121 of the resin layer 120 as shown in Fig. 1 is not provided with a region free from low protrusions. In addition, when the value G is equal to or less than the upper limit of the above range, the surface 121 of the resin layer 120 shown in Fig. 1 is not provided, and a partial region having excessively low projections is not provided, and no high projections are provided. region. Therefore, when the value G is equal to or less than the upper limit of the above range, it is shown that the low protrusion and the high protrusion can be combined in a well-balanced manner. Further, when the value G is equal to or greater than the lower limit of the above range, the number of protrusions is appropriate, and the number of protrusions can be suppressed to such an extent that the internal haze is not raised. Therefore, by setting the value G within the above range, it is possible to suppress the occurrence of convex defects and to reduce the internal haze when winding up the film roll.

Further, the protrusion on the surface of the resin layer opposite to the base film satisfies N _B ≧N _C ≧N _D ≧N _E ≧N _F . This means that the number of protrusions having a low height is more than the number of protrusions having a high height. By satisfying such a necessary condition, the smoothness of the surface of the protrusion having the resin layer can be improved, and the internal haze of the resin layer can be reduced.

The height and the number of the protrusions described above can be controlled, for example, by adjusting the size of the particles contained in the resin layer, the state in which the solvent is evaporated when the resin layer is produced, the order of steps for forming the resin layer, and the like. The so-called in this specification "Solvent" is not only a solvent but also a dispersion medium.

The resin layer contains particles. In the resin layer, the particles have a function of forming protrusions on the surface of the resin layer opposite to the base film. Further, usually, the resin layer contains a polymer. Hereinafter, the polymer is appropriately referred to as a "binding polymer". In the resin layer, the binder polymer has a function of keeping the particles from being detached from the resin layer and a function of adhering the resin layer to the substrate film. The resin layer containing the particles and the polymer-attached polymer can be usually produced by a production method comprising the steps of: mixing the particles and the binder polymer to obtain a fluid resin; and coating the fluid resin in a step of forming a resin film on the substrate film; and a step of curing and/or drying the resin film formed on the substrate film to obtain a resin layer. Hereinafter, the above-mentioned resin in the form of a fluid used for forming a resin layer is referred to as a "coating resin". Hereinafter, the manufacturing method will be described.

As the binder polymer, it can be arbitrarily used as appropriate for the use of the multilayer film. In particular, from the viewpoint of stably preventing the convex defects when the plurality of layers of the film are formed into a film roll, it is preferred that the polymer is contained to contain the polyurethane.

As the polyurethane, for example, a polyurethane obtained by reacting (i) a component containing an average of two or more active hydrogens per molecule with (ii) a polyisocyanate component can be used.

Moreover, as the polyurethane, for example, a polyurethane which is produced by using a chain extender with an isocyanate group-containing prepolymer and chain extension, and adding water as a dispersion can be used. The isocyanate group-containing prepolymer can be produced by subjecting the component (i) and the component (ii) to a urethanization reaction under conditions in which an isocyanate group is excessive. The urethanation reaction can be carried out in an organic solvent which is inert to the reaction and has a high affinity with water. Also, isocyanate-containing The prepolymer can also be neutralized prior to chain extension of the prepolymer. The chain extension method of the isocyanate group-containing prepolymer includes a method in which an isocyanate group-containing prepolymer and a chain extender are reacted in the presence of an optional catalyst. In this case, as the chain extender, water, a water-soluble polyamine, a glycol, or the like can be used.

The component (i) is preferably an active hydrogen having a hydroxyl group, and for example, a compound having an average of two or more hydroxyl groups per molecule is preferred. Specific examples of the component (i) include the following (1) polyol compound, (2) polyether polyglycol, (3) polyester polyglycol, (4) polyether ester polyol, and ( 5) Polycarbonate polyol.

(1) Polyol compound:

Examples of the polyol compound include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butanediol, 1,3-butylene glycol, and 2,3-butanediol. , 4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1, 3-pentanediol, tricyclodecane dimethanol, 1,4-cyclohexanedimethanol, 2,2-dimethylpropanediol, 1,4-butanediol, 1,6-hexanediol, 1, 8-octanediol, glycerin, trimethylolpropane, and the like.

(2) Polyether polyol:

Examples of the polyether polyol include an alkylene oxide adduct of the above (1) polyol compound; a ring-opening (co)polymer of an alkylene oxide and a cyclic ether (for example, tetrahydrofuran); and polyethylene glycol; Polypropylene glycol, ethylene glycol-propylene glycol copolymer, 1,4-butanediol copolymer; glycols such as diol, polytetramethylene glycol, polyhexylene glycol, and polyoctanediol. Specific examples of the polyether polyol include a poly(oxypropylene ether) polyol, a poly(ethylene oxide-propylene ether) polyol, and the like.

(3) Polyester polyol:

The polyester polyol is, for example, obtained by polycondensing a polyvalent carboxylic acid or an anhydride thereof with the above-mentioned (1) polyol compound under conditions in which a hydroxyl group is excessive. Here, examples of the polyvalent carboxylic acid include adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, citric acid, isodecanoic acid, p-citric acid, and the like. a dicarboxylic acid; a tricarboxylic acid such as benzenetricarboxylic acid. Specific examples of the polyester polyol include ethylene glycol-adipate condensate, butanediol-adipate condensate, hexanediol-adipate condensate, and ethylene glycol-propylene glycol-hexane. An acid condensate or a polylactone diol obtained by ring-opening polymerization of a lactone using a diol as a starting agent.

(4) Polyether ester polyol:

The polyether ester polyol may, for example, be an ether group-containing polyol; or a mixture thereof with another diol, a polycarboxylic acid as exemplified in the above (3) or an anhydride thereof, and an epoxy resin; The alkane reacts to the like. Here, examples of the ether group-containing polyol include the above (2) polyether polyol, diethylene glycol, and the like. Specific examples of the polyether ester polyol include a polytetramethylene glycol-adipate condensate and the like.

(5) Polycarbonate polyol:

The polycarbonate polyol may, for example, be a compound represented by the formula: HO-R-(OC(O)-OR) _x -OH. In the above formula, R represents a saturated fatty acid polyol residue having 1 to 12 carbon atoms. Further, in the above formula, X represents the number of structural units of the molecule, and is usually an integer of 5 to 50. These can be obtained by a transesterification method in which a saturated aliphatic polyol and a substituted carbonate (for example, diethyl carbonate, diphenyl carbonate, etc.) are reacted under conditions in which a hydroxyl group is excessive; The method of reacting the above saturated aliphatic polydiol with phosgene or, if necessary, further reacting it with a saturated aliphatic polyol.

These (i) components may be used alone or in combination of two or more types in any ratio.

The component (ii) which is reacted with the component (i) (that is, the isocyanate component) may, for example, be a compound containing an average of two or more isocyanate groups per molecule. The compound may be an aliphatic compound, an alicyclic compound, or an aromatic compound.

The aliphatic polyisocyanate compound is preferably an aliphatic diisocyanate having 1 to 12 carbon atoms, such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, or hexane diisocyanate. (HDI) and so on.

The alicyclic polyisocyanate compound is preferably an alicyclic diisocyanate having 4 to 18 carbon atoms, and examples thereof include 1,4-cyclohexane diisocyanate, methylcyclohexyl diisocyanate, and isophor. Keto diisocyanate (IPDI), bicyclocyclohexylmethane diisocyanate (HMDI), and the like.

Examples of the aromatic polyisocyanate include toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate, and benzodimethyl diisocyanate.

These components (ii) may be used alone or in combination of two or more kinds in any ratio.

The above-mentioned (i) component and (ii) component can be arbitrarily selected and used depending on the use of the plurality of layers of the film. In particular, as the component (i), it is preferred to use a bond having a pressure which is not easily hydrolyzable, and specifically, it is preferred to use (2) a polyether polyol and (5) a polycarbonate polyol, particularly ( 2) Polyether polyols are particularly preferred.

Further, these polyurethanes may also have an acid structure in their molecular structure. Polyurethane with acid structure because no surfactant is used, or even Since the amount of the surfactant is small and it can be dispersed in water, it is expected to improve the water resistance of the resin layer. This is called self-emulsifying type, meaning that even without the surfactant, the particles of the polyurethane can be dispersed and stabilized only in water by molecular ionicity. Further, since the polyurethane having an acid structure does not require a surfactant or a small amount, it has excellent adhesion to the base film and can maintain high transparency.

Examples of the acid structure include an acid group in the case of a carboxyl group (-COOH) or a sulfo group (-SO ₃ H). Further, in the polyurethane, the acid structure may be present in the side chain or may be present at the terminal. One type of the acid structure may be used, or two or more types may be used in combination at any ratio.

The amount of the acid structure is preferably 20 mgKOH/g or more, preferably 25 mgKOH/g or more, more preferably 250 mgKOH/g or less, and preferably 150 mgKOH/g or less, based on the acid value of the coating resin. When the acid value is at least the lower limit of the above range, the water dispersibility of the polyurethane can be improved. Moreover, when it is less than the upper limit, the water resistance of the resin layer can be improved.

As a method of introducing an acid structure into a polyurethane, for example, a part or all of the components (i) described in the above (2) to (4) are substituted with dimethylol alkanoic acid, and a carboxyl group is introduced in advance to A method of a polyether polyol, a polyester polyol, a polyether ester polyol, or the like. Here, examples of the dimethylol alkanoic acid to be used include dimethylol acetic acid, dimethylolpropionic acid, and dimethyloltyrosic acid. The dimethylol alkanoic acid may be used alone or in combination of two or more kinds in any ratio.

Part or all of the acid structure contained in the polyurethane may also be neutralized by a non-volatile base. By neutralizing the acid structure, the multiple layers of the film have The thermal experience of exposure to high temperatures can also maintain the properties as an optical material or can be followed by other components with a strong adhesion. Further, even if the acid structure is neutralized, the amount of the surfactant or the surfactant is not used, and the particles of the polyurethane can be dispersed in the water.

Among the acid structures contained in the polyurethane, the ratio of the neutralized acid structure is preferably 20% or more, and particularly preferably 50% or more. By neutralizing 20% or more of the acid structure, the plurality of films can maintain the characteristics as an optical material even if they have a thermal experience of being exposed to a high temperature, or can be adhered to other members with a strong adhesion.

In order to be able to react with the crosslinking agent, the polyurethane preferably contains a polar group. Examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a stanol group, a decyl group, an amine group, a nitrile group, and a sulfo group. In particular, a methylol group, a hydroxyl group, a carboxyl group and an amine group are preferred, and a hydroxyl group and a carboxyl group are preferred, and a carboxyl group is particularly preferred. The amount of the polar group in the polyurethane is preferably 0.0001 equivalent/1 kg or more, preferably 0.001 equivalent/1 kg or more, and preferably 1 equivalent/1 kg or less.

As the polyurethane, a commercially available one can be used as the aqueous urethane resin. The aqueous urethane resin contains a composition of polyurethane and water, and is usually a composition in which polyurethane and optionally any component contained in water are dispersed in water. As the water-based urethane resin, for example, "Adeka Bontighter" series manufactured by ADEKA Co., Ltd., "OLESTAR" series manufactured by Mitsui Chemicals Co., Ltd., "Bondik" series manufactured by DIC Corporation, "HYDRAN (WLS201, WLS202, etc.)" series, BAYER can be used. "Impranil" series made by the company, "POISE" series made by Kao Corporation, "Sanpren" series by Sanyo Chemical Industry Co., Ltd., and the first industrial system The "SUPERFLEX" series made by the company, the "NEOREZ" series made by Nanben Chemical Co., Ltd., and the "Sancure" series made by LUBRIZOL. Further, the polyurethane type may be used alone or in combination of two or more types in any ratio.

Further, the glass transition temperature of the polymer to be bonded is preferably 50 ° C or higher, preferably 55 ° C or higher, particularly preferably 60 ° C or higher, preferably 150 ° C or lower, preferably 125 ° C or lower, particularly preferably Below 100 °C. By setting the glass transition temperature of the polymer-bonded polymer to the lower limit or more of the above range, it is possible to prevent contamination of the conveyance roller on the downstream side of the oven after the production step is discharged from the drying furnace. Further, by setting it to the upper limit or less, it is possible to prevent the plurality of layers from being curled.

In the fluid coating resin, the state in which the polymer is bonded is arbitrary, and it may be dispersed in a granular form, or may be dissolved in other components such as a solvent. For example, when polyurethane is used as the binding polymer, the polyurethane is mostly dispersed in a granular form. At this time, from the viewpoint of the optical characteristics of the plurality of layers of films, the average particle diameter of the particles of the polyurethane is preferably 0.01 μm to 0.4 μm.

As the particles, any of inorganic particles composed of an inorganic material, organic particles composed of an organic material, and composite particles contained by combining an inorganic material and an organic material can be used. However, from the viewpoint of easily forming a resin layer, it is preferred to use water-dispersible particles. Examples of the material of the inorganic particles include inorganic oxides such as cerium oxide, titanium oxide, aluminum oxide, and zirconium oxide; calcium carbonate, talc, clay, calcined kaolin, calcined calcium citrate, calcium citrate hydrate, and cesium. Aluminum acid, magnesium citrate, calcium phosphate, and the like. Moreover, when the material of the organic particle is mentioned, a polyphthalocyanine resin, a fluororesin, an acryl resin, etc. are mentioned, for example. These may be used alone or in combination of two or more types in any ratio.

Among the materials of the particles exemplified, ruthenium oxide is preferred. The particles of cerium oxide have excellent ability to suppress wrinkles and transparency, and are less likely to generate internal haze and are not colored, so that the influence on the optical characteristics of the plurality of layers of film is small. Further, the cerium oxide is excellent in dispersibility and dispersion stability in the coating resin. Among the particles of cerium oxide, amorphous colloidal cerium oxide particles are particularly preferred.

As the cerium oxide particles as described above, a commercially available product can also be used. When an example of a commercially available product is used, EPOSTA-MX-050W (average particle diameter: 80 nm), EPOSTAR-KE-W10 (average particle diameter: 110 nm), and EPOSTAR-MX-100W (average) are available from Nippon Shokubai Co., Ltd. Particle size: 150 nm to 200 m); SNOWTEX MP-2040 (average seat diameter: 150 nm to 200 nm) manufactured by Nissan Chemical Co., Ltd.

Further, as the particles, a surface which is opposite to the base film of the resin layer can be used to form a protrusion satisfying the above-described requirements. Generally, the height of the aforementioned protrusions can be adjusted in accordance with the size of the particles. At this time, the diameter of the particles is not directly the height of the protrusions, but since the diameter of the particles and the height of the protrusions are generally associated, by adjusting the distribution of the diameter of the particles, it is possible to form the surface of the resin layer as described above. Widely distributed protrusions.

Usually, by using a plurality of kinds of particles having different average particle diameters, a protrusion satisfying the above-described requirements is formed on the surface of the resin layer. Therefore, the particles of the resin layer are usually contained by combining a plurality of particles having different average particle diameters. When a plurality of particles having different average particle diameters are combined, the particle size distribution of the entire particles of the resin layer can be made large, so that the protrusions formed on the surface of the resin layer containing the particles can be formed. Widely distributed. Therefore, in this production method, the step of mixing the particles and the binder polymer to obtain a coating resin is preferably a step of mixing a plurality of particles having different average particle diameters with the binder polymer.

Further, when a plurality of kinds of particles having different average particle diameters are used in combination, it is preferred that at least one of the particles has an average particle diameter larger than the thickness of the resin layer. As described above, by having particles having an average particle diameter larger than the thickness of the resin layer, it is possible to efficiently form protrusions satisfying the above-described requirements on the surface of the resin layer opposite to the base film. Further, at least one of the plurality of particles may have an average particle diameter smaller than a thickness of the resin layer.

In particular, when the particles (S) having an average particle diameter of less than 150 nm are used, it is preferably used in combination with particles (L) having an average particle diameter of 150 nm or more. Therefore, the particles of the resin layer are preferably contained in combination with particles (S) having an average particle diameter of less than 150 nm and particles (L) having an average particle diameter of 150 nm or more.

The average particle diameter of the particles (S) is usually 20 nm or more, preferably 30 nm or more, preferably 40 nm or more, and usually less than 150 nm, preferably 140 nm or less, and more preferably 130 nm or less. By setting the average particle diameter of the particles (S) to be equal to or higher than the lower limit of the above range, the protrusions can be stably formed on the surface of the resin layer. Moreover, by setting it as an upper limit or less, the height distribution of the protrusion of a resin layer can be wide.

Moreover, the average particle diameter of the particles (S) is preferably twice or more, more preferably 3 times or more, particularly preferably 4 times or more, and 15 times the height of the highest frequency of the protrusions formed on the surface of the resin layer. The following is preferable, preferably 14 times or less, and particularly preferably 13 times or less. Here, the height of the highest frequency of the protrusion means the height of the protrusions of 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, and 30 nm, and the protrusion having the height is the height of the protrusion. By setting the average particle diameter of the particles (S) to be equal to or higher than the lower limit of the above range, the protrusions can be stably formed on the surface of the resin layer. Further, by being equal to or less than the upper limit value, the protrusion of the resin layer can be formed. Widely distributed.

Further, the average particle diameter of the particles (S) is preferably 3 times or more, more preferably 4 times or more, particularly preferably 5 times or more, more preferably 10 times or less, and more preferably 8 or less, based on the thickness of the resin layer. Below the times, it is particularly preferably 7 times or less. By setting the average particle diameter of the particles (S) to be equal to or higher than the lower limit of the above range, the protrusions can be stably formed on the surface of the resin layer. Moreover, by setting it as an upper limit or less, the height distribution of the protrusion of a resin layer can be wide.

The amount of the particles (S) is usually 2 parts by weight or more, preferably 3 parts by weight or more, more preferably 5 parts by weight or more, usually 24 parts by weight or less, or 20 parts by weight or less based on 100 parts by weight of the polymer to be bonded. The following is preferred, and it is preferably 18 parts by weight or less. By setting the amount of the particles (S) within the above range, it is possible to easily form protrusions satisfying the above-described requirements on the surface of the resin layer.

The average particle diameter of the particles (L) is usually 150 nm or more, preferably 160 nm or more, preferably 170 nm or more, and usually 250 nm or less, preferably 230 nm or less, and more preferably 200 nm or less. By setting the average particle diameter of the particles (L) to be equal to or higher than the lower limit of the above range, the height distribution of the protrusions on the resin layer can be made wide. Moreover, by setting it as an upper limit or less, the internal haze of a resin layer can be reduced.

Further, the average particle diameter of the particles (L) is preferably 15 times or more, preferably 16 times or more, particularly preferably 17 times or more, and 25 times the height of the highest frequency of the protrusions formed on the surface of the resin layer. The following is preferable, preferably 23 times or less, and particularly preferably 20 times or less. By setting the average particle diameter of the particles (L) to be equal to or higher than the lower limit of the above range, the height distribution of the protrusions on the resin layer can be made wide. Moreover, by setting it as an upper limit or less, the internal haze of a resin layer can be reduced.

Further, the average particle diameter of the particles (L) is preferably 2 or more, more preferably 3 or more, particularly preferably 4 or more, more preferably 10 or less, and most preferably 8 or less, with respect to the thickness of the resin layer. Below the times, it is particularly preferably 7 times or less. By setting the average particle diameter of the particles (L) to be equal to or higher than the lower limit of the above range, the height distribution of the protrusions on the resin layer can be made wide. Moreover, by setting it as an upper limit or less, the internal haze of a resin layer can be reduced.

Further, the difference between the average particle diameter of the particles (S) and the average particles of the particles (L) is preferably 70 nm or more, more preferably 100 nm or more, particularly preferably 120 nm or more, more preferably 200 nm or less, and most preferably 180 nm or less, particularly preferably 160 nm or less. By setting the difference between the average particle diameter of the particles (S) and the average particle diameter of the particles (L) within the above range, it is possible to easily form protrusions satisfying the above-described requirements on the surface of the resin layer.

The amount of the particles (L) is usually 5 parts by weight or more, preferably 6 parts by weight or more, more preferably 7 parts by weight or more, usually 20 parts by weight or less, or 18 parts by weight or less or less based on 100 parts by weight of the polymer. Preferably, it is preferably 15 parts by weight or less. By setting the amount of the particles (L) within the above range, it is possible to easily form protrusions satisfying the above-described requirements on the surface of the resin layer.

The difference between the amount of the particles (L) and the amount of the particles (S) is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, particularly preferably 2 parts by weight or more, based on 100 parts by weight of the polymer to be bonded. It is preferably 25 parts by weight or less, preferably 20 parts by weight or less, and particularly preferably 15 parts by weight or less. When the difference between the amount of the particles (L) and the amount of the particles (S) falls within the above range, it is possible to easily form protrusions satisfying the above-described requirements on the surface of the resin layer.

Usually, the particles (S) are used in combination with the particles (L) as described above. In the case of the particle size distribution of the entire particles contained in the resin layer, peaks corresponding to the respective particles (S) and particles (L) appear. However, even in such a case, the height distribution of the protrusions formed on the surface of the resin layer usually shows a single peak. Thus, the distribution of the particle diameter does not simply correspond to the height distribution of the protrusions. However, when a plurality of kinds of particles having different average particle diameters are combined as described above, the particle size distribution of the entire particles is widened, and in the same manner, the height distribution of the protrusions formed on the surface of the resin layer is also widened. Therefore, by using the distribution of the average particle diameter of such particles in association with the height distribution of the protrusions, it is possible to obtain protrusions satisfying the above-described requirements.

Further, the coating resin may contain a crosslinking agent in addition to the particles and the binding polymer. The cross-linking agent forms a bond by reacting with a reactive group of the binder polymer to crosslink the binder polymer. Therefore, for example, after the coating resin is applied to the base film, the binder polymer is crosslinked, whereby the adhesion between the resin layer and the base film, and the mechanical strength and moist heat resistance of the resin layer can be improved. For example, when a polyurethane is used as the binding polymer, the crosslinking agent can be usually reacted with a hydroxyl group or the like which contains the carboxyl group and the anhydride group as the acid structure, and the (i) component and the component (ii). The polar group reacts to form a crosslinked structure.

As the crosslinking agent, for example, a compound having two or more functional groups capable of reacting with a group having reactivity with a binder polymer in one molecule and forming a bond can be used. In particular, as the crosslinking agent, a compound having a functional group capable of reacting with a carboxyl group or an anhydride group thereof is preferred.

Specific examples of the crosslinking agent include an epoxy compound, a carbodiimide compound, an oxazoline compound, and an isocyanate compound. Also, the crosslinking agent can be single One type may be used alone, and two or more types may be used in combination at any ratio.

As the epoxy compound, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. In particular, the epoxy compound is preferably one which is soluble in water or emulsifiable in water. When the epoxy resin is soluble in water or can be emulsified and liquefied, and the coating resin is an aqueous resin, the coating property of the aqueous resin can be improved. Therefore, the resin layer can be easily produced. Here, the water-based resin refers to a fluid-like resin containing a solid component such as a polymer in a state of being dissolved or dispersed in an aqueous solvent such as water.

Examples of the epoxy compound include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, and 1,6-hexanediol. a diol 1 molar which is a neopentyl glycol or the like, and a diepoxide compound obtained by etherification with epichlorohydrin 2 mole; glycerin, polyglycerol, methylolpropane, pentaerythritol, sorbose a polyepoxide such as an alcohol such as alcohol, a mole of epichlorohydrin or more, and a polyepoxy compound obtained by etherification of epichlorohydrin 2 mole; citric acid, citric acid, oxalic acid, adipic acid, or the like. A diepoxy compound obtained by esterification of a dicarboxylic acid 1 molar and an epichlorohydrin 2 molar.

More specifically, examples of the epoxy compound include 1,4-bis(2',3'-glycidoxy)butane and 1,3,5-triepoxypropyl heterotrimer. Cyanate ester, 1,3-diepoxypropyl-5-(γ-acetoxy-β-oxypropyl)isocyanate, sorbitol polyepoxypropyl ether, polyglycerol Polyepoxypropyl ethers, neopentyl alcohol polyepoxypropyl ethers, diglycerol polyepoxypropyl ether, 1,3,5-triepoxypropyl (2-hydroxyethyl) heterotrimer Cyanate ester, glycerol polyglyceryl ether and trimethylolpropane polyepoxypropyl ether.

In addition, when the example of the epoxy compound is mentioned as a commercial item, the "DENACOL (DENACOL EX-521, EX-614B, etc.) series etc. by NAGASE CHEMTEX company are mentioned.

The epoxy compound may be used alone or in combination of two or more kinds in any ratio.

The amount of the epoxy compound is usually 5 parts by weight or more, preferably 7 parts by weight or more, preferably 10 parts by weight or more, usually 50 parts by weight or less, and 40 parts by weight or less, based on 100 parts by weight of the polymer to be bonded. Preferably, it is 30 parts by weight or less. When the amount of the epoxy compound is at least the lower limit of the above range, since the reaction between the epoxy compound and the binder polymer proceeds sufficiently, the mechanical strength of the resin layer can be appropriately increased. In addition, by setting it to the upper limit or less, it is possible to reduce the residual of the unreacted epoxy compound and to appropriately increase the mechanical strength of the resin layer.

Further, the amount of the epoxy compound is preferably 0.2 times or more, more preferably 0.4 times or more, and particularly preferably 0.6 times by weight based on the amount of the epoxy compound equivalent to the polar group of the binder polymer. The above is preferably 1.4 times or less, preferably 1.2 times or less, and particularly preferably 1.0 times or less. Here, the amount of the epoxy compound which is equivalent to the polar group of the binder polymer means the theoretical amount of the epoxy compound which can react with the total amount of the polar group of the binder polymer without excessive or insufficient. The polar group of the attached polymer is capable of reacting with the epoxy group of the epoxy compound. Therefore, by setting the amount of the epoxy compound within the above range, the reaction between the polar group and the epoxy compound can be carried out to an appropriate extent, and the mechanical strength of the resin layer can be effectively enhanced.

As a carbodiimide compound, it can be used in 1 molecule. More than one carbodiimide group compound. The carbodiimide compound can be produced by using an organic isocyanate such as an organic monoisocyanate, an organic diisocyanate or an organic triisocyanate as a raw material. Examples of such organic isocyanates include aromatic isocyanates, aliphatic isocyanates, and the like. Therefore, as the organic group of the organic isocyanate, any of an aromatic group and an aliphatic group may be used, and an aromatic organic group and an aliphatic organic group may be used in combination. In particular, from the viewpoint of reactivity, an organic isocyanate having an aliphatic organic group is particularly preferred. Usually, the carbodiimide compound can be synthesized by a condensation reaction of an organic diisocyanate.

Specific examples of the organic isocyanate include 4,4'-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,4-phenylene diisocyanate, and 2,4-toluene. Isocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, decyl diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4'- Organic diisocyanate such as dicyclohexylmethane diisocyanate or 1,3-benzene diisocyanate; isophorone isocyanate, phenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, isocyanate An organic monoisocyanate such as an ester.

When an example of a carbodiimide compound is used as a commercial product, "CARBODILITE (CARBODILITE V-02, V-02-L2, SV-02, V-04, manufactured by Nissin Textile Chemical Co., Ltd.) can be obtained as a commercial product. , E-02, etc.) series.

The carbodiimide compound may be used alone or in combination of two or more kinds in any ratio.

Carbon diimine compounding relative to 100 parts by weight of the binding polymer The amount of the substance is usually 1 part by weight or more, preferably 3 parts by weight or more, usually 40 parts by weight or less, more preferably 30 parts by weight or less. When the amount of the carbodiimide compound is at least the lower limit of the above range, the reaction between the carbodiimide compound and the binder polymer proceeds sufficiently, and the mechanical strength of the resin layer can be appropriately increased. In addition, the amount of the unreacted carbodiimide compound remaining is small, and the mechanical strength of the resin layer can be appropriately increased.

As the oxazoline compound, a polymer having an oxazoline group represented by the following formula (1) can be used, and in the following formula (1), R ¹ , R ² , R ³ and R ⁴ may be the same or different and represent Any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, a phenyl group, and a substituted phenyl group.

The oxazoline compound is, for example, an addition polymerizable oxazoline, and optionally contains a monomer component of an unsaturated monomer, and is produced by solution polymerization in an aqueous medium by a conventional polymerization method. The addition polymerization oxazoline is, for example, a compound represented by the following formula (II). In the following formula (II), R ¹ , R ² , R ³ and R ⁴ are the same as defined in the formula (1). Further, R ⁵ represents an acyclic organic group having an addition polymerizable unsaturated bond.

Specific examples of the addition polymerization oxazoline include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, and 2-vinyl-5. -methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl- 2-oxazoline and the like. Further, these may be used alone or in combination of two or more types in any ratio. Among these, 2-isopropenyl-2-oxazoline is also easily obtained industrially, and is preferred.

The amount of the addition polymerizable oxazoline is preferably 3 parts by weight or more based on 100 parts by weight of the total monomer component used for producing the oxazoline compound. In this case, when the coating resin containing the oxazoline compound is cured, the curing can be sufficiently progressed, and a resin layer having excellent durability and water resistance can be obtained.

As the arbitrary unsaturated monomer which can be used for the production of the oxazoline compound, any monomer which can be copolymerized with the addition polymerizable oxazoline and does not react with the oxazoline group can be used. Such an optional unsaturated monomer can be arbitrarily selected and used from the above monomers.

In the case of the oxazoline compound, a water-soluble type is exemplified by EPOCROSS WS-500 and WS-700 manufactured by Nippon Shokubai Co., Ltd., and an emulsion type, for example, a product manufactured by Nippon Shokubai Co., Ltd. EPOCROSS K-2010, K-2020 and K-2030. Among these, it is combined with the coating resin. The water-soluble type having a high reactivity of the compound is preferable, and the oxazoline compound may be used alone or in combination of two or more types in any ratio.

The amount of the oxazoline compound may be such that the polar group of the polymer and the molar ratio of the oxazoline group of the oxazoline compound (the number of moles of the polar group / the molar number of the oxazoline group) may be Set in the way of falling within the predetermined range. Specifically, the aforementioned molar ratio can be set to be 100/20 to 100/100. By setting the above molar ratio to be equal to or higher than the lower limit of the above range, it is possible to prevent the unreacted polar group from remaining. Further, by setting it to the upper limit or less, it is possible to prevent the occurrence of the remaining oxazoline group and prevent the excess of the hydrophilic group.

Further, in the case where the binding polymer has a carboxyl group and the carboxyl group is neutralized, the oxazoline group and the carboxylate do not easily react in the reaction of the binding polymer with the oxazoline compound. Therefore, the reactivity can be controlled by adjusting the kind and non-volatile degree of the nonvolatile base used for neutralization.

As the isocyanate compound, a compound having two or more isocyanate groups in one molecule can be used. These isocyanate compounds may be aliphatic compounds, alicyclic compounds, or aromatic compounds. Specific examples of the isocyanate compound include the same examples of the component (ii) which has been described as a raw material of the polyurethane.

Among the above-mentioned crosslinking agents, an epoxy compound and a carbodiimide compound are preferred, and an epoxy compound is particularly preferred. When an epoxy compound is used as a crosslinking agent, the adhesiveness of a resin layer and a base film can be improved especially large. Further, when the carbodiimide compound is used as a crosslinking agent, the pot life of the coating resin can be improved.

Further, the coating resin may be in addition to the particles and the binding polymer. Contains a non-volatile base. The non-volatile base may be a substantially non-volatile base under the treatment conditions after the coating resin is applied to the base film and dried. As the above-mentioned processing conditions, for example, a treatment of leaving at 80 ° C for 1 hour can be mentioned. Here, the term "substantially nonvolatile" generally means that the amount of reduction of the nonvolatile base is 80% or less. Such a nonvolatile base can function as an neutralizing agent for an acid structure contained in a binder polymer such as polyurethane.

As the nonvolatile base, an inorganic base can be used, and an organic base can also be used. In particular, an organic base having a boiling point of 100 ° C or higher is preferred, and an amine compound having a boiling point of 100 ° C or higher is preferred, and an amine compound having a boiling point of 200 ° C or higher is particularly preferred. Further, the organic base may be a low molecular compound or a polymer.

Examples of the nonvolatile base, and examples of the inorganic base include sodium hydroxide and potassium hydroxide. Further, examples of the organic base include 2-amino-2-methyl-1-propanol (AMP), triethanolamine, triisopropanolamine (TIPA), monoethanolamine, diethanolamine, and tris[(2- Hydroxy)-1-propyl]amine, 2-amino-2-methyl-1,3-propanediol (AMPD), 2-amino-2-hydroxymethyl-1,3-propane potassium hydroxide, zinc Ammonium complex, copper ammonium complex, silver ammonium complex, γ-aminopropyl triethoxy decane, γ-aminopropyl trimethoxy decane, N-β (amine ethyl)-γ-amine Propyltrimethoxydecane, N-β (aminoethyl)-γ-aminopropyltrimethyldimethoxydecane, N-phenyl-γ-aminopropyltrimethoxydecane, N,N-double (trimethyldecyl)urea, 3-ureidopropyltrimethoxydecane, 3-aminopropyl-parade (2-methoxy-ethoxy-ethoxy)decane, N-methyl-3- Aminopropyltrimethoxycarboxylic acid diterpene, bismuth oxalate, diammonium malonate, diterpene succinate, diammonium adipate, diterpene azelaic acid, dodecanedioic acid Oh, Diterpenic acid diterpene, p-quinone decanoate, quinoline, methyridine, pyridine, morpholine, piperazine, cyclohexylamine, hexamethylenediamine, N,N-dimethylformamide, B Diamine, two Ethylenetriamine, tetraethyleneamine, pentaethyleneamine, monoethanolamine, diethanolamine, isopropanolamine, N,N-diethylmethanolamine, N,N-dimethylethanolamine, amine ethyl Ethanolamine, N-methyl-NN-diethanolamine, 1,2-propylenediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, Isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-ring Hexanediamine, amine ethylethanolamine, amine propylethanolamine, amine hexylethanolamine, amine ethylpropanolamine, amine propylpropanolamine, amine hexylpropanolamine, diethylenetriamine, dipropyl propyl Imidazole, 1-(2-aminoethyl)-2-methylimidazole, 1-(2-aminoethyl)-2-ethylimidazole, 2-aminoimidazolium sulfate, 2-(2-aminoethyl) -benzimidazole, pyrazole, 5-aminopyrazole, 1-methyl-5-aminopyrazole, 1-isopropyl-5-aminopyrazole, 1-benzyl-5-amino group Pyrazole, 1,3-dimethyl-5-aminopyrazole, 1-isopropyl-3-methyl-5-aminopyrazole, 1-benzyl-3-methyl-5-amino group Pyrazole, 1-methyl-4-chloro-5-aminopyrazole, 1-methyl-4-amino-5-aminopyrazole, 1-iso 4-chloro-5-aminopyrazole, 3-methyl-4-chloro-5-aminopyrazole, 1-benzyl-4-chloro-5-aminopyrazole, amine based resin (eg , 1,3-dimethyl-4-chloro-melamine resin, urea resin, guanamine resin, etc.). Further, these may be used alone or in combination of two or more types in any ratio.

The amount of the nonvolatile base is usually 0.5 parts by weight or more, preferably 1 part by weight or more, more preferably 2 parts by weight or more, usually 30 parts by weight or less, or 20 parts by weight or less based on 100 parts by weight of the polymer to be bonded. The following is preferred, and it is preferably 10 parts by weight or less. When the amount of the nonvolatile base is at least the lower limit of the above range, a sufficient adhesion can be obtained. Moreover, by setting it as an upper limit or less, the discoloration of the polarizer of polyvinyl alcohol can be prevented.

Moreover, the coating resin can also be used in addition to the particles and the binding polymer. Contains a humectant. By using a wetting agent, the coating property at the time of applying a coating resin to a base film becomes favorable.

As the wetting agent, for example, an acetylene surfactant, a fluorine surfactant, or the like can be used. As the acetylene-based surfactant, for example, SURFYNOL series, Dynol series, etc., manufactured by AIR PRODUCTS AN _D CHEMICALS, can be used. In addition, as the fluorine-based surfactant, for example, MEGAFAC series manufactured by DIC Corporation, Futagent series manufactured by NEOS Corporation, and SURFLON series manufactured by AGC Corporation can be used. From the viewpoint of recoatability, it is preferred to use an acetylene surfactant as the wetting agent.

Further, these may be used alone or in combination of two or more types in any ratio.

The amount of the wetting agent is usually 0.01% by weight or more, preferably 0.05% by weight or more, preferably 0.1% by weight or more, usually 5% by weight or less, and 4 parts by weight based on the solid content of the coating resin. It is preferably 5% or less, preferably 3% by weight or less. When the amount of the wetting agent is at least the lower limit of the above range, sufficient coatability can be obtained. Moreover, by setting it as an upper limit or less, it can suppress the bleed-out of a humectant, and can make a recoatability favorable.

The coating resin usually contains a solvent. As the solvent, water or a water-soluble solvent is used. Examples of the water-soluble solvent include methanol, ethanol, isopropanol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethyl hydrazine, ethylene glycol monomethyl ether, and ethylene glycol monobutyl ether. Wait. As the solvent, it is especially preferred to use water. Further, the solvent may be used alone or in combination of two or more kinds in any ratio.

The amount of the solvent can make the viscosity of the coating resin suitable The manner of coating is set. Usually, the amount of the solvent is set so that the solid content concentration of the coating resin falls within a desired range. The above-mentioned range is preferably 0.5% by weight or more, preferably 1% by weight or more, more preferably 15% by weight or less, and most preferably 10% by weight or less. Thereby, the handleability and coatability of a coating resin can be made favorable.

The coating resin may contain a curing accelerator in combination with the above-mentioned crosslinking agent. For example, in the case of using an epoxy compound as a crosslinking agent, as a hardening accelerator, a third-order amine compound (except for a 2,2,6,6-tetramethylpiperidinyl group having a tertiary amine at the 4-position) Other than the compound), a boron fluoride compound or the like is preferred. Further, the curing accelerator may be used alone or in combination of two or more kinds in any ratio.

The amount of the curing accelerator is usually 0.001 parts by weight or more, preferably 0.01 parts by weight or more, preferably 0.03 parts by weight or more, usually 30 parts by weight or less, or 10 parts by weight or less, based on 100 parts by weight of the polymer to be bonded. Preferably, it is preferably 5 parts by weight or less.

The coating resin may be combined with the aforementioned crosslinking agent to contain a curing aid. Specific examples of the hardening aid include bismuth, benzoquinone, p-nitrosophenol, and the like. a nitroso-based hardening aid; a maleic acid-based hardening aid such as N,N-meta-phenyl bis-butenylene diimide; diallyl citrate, cyanuric acid Allyl-based hardening aids such as allyl ester and triallyl cyanurate; methacrylate-based hardening of ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate Auxiliary; an ethylene-based hardening aid such as vinyl toluene, ethylvinylbenzene or divinylbenzene. Further, the curing aid may be used alone or in combination of two or more kinds in any ratio.

The amount of the curing aid is usually 1 part by weight or more based on 100 parts by weight of the crosslinking agent, preferably 10 parts by weight or more, usually 100 parts by weight or less, and preferably 50 parts by weight or less.

The coating resin may contain, for example, a heat stabilizer, a weather stabilizer, a leveling agent, a surfactant, an antioxidant, an antistatic agent, a slip agent, an anti-adhesive agent, and an anti-fog, as long as the effect of the present invention is not significantly impaired. Agents, slip agents, dyes, pigments, natural oils, synthetic oils, waxes, and the like. Further, these may be used alone or in combination of two or more types in any ratio.

In the step of obtaining a coating resin, the particles and the binding polymer, and optionally a crosslinking agent, a nonvolatile base, a wetting agent, a solvent, and an optional component are mixed to obtain a fluid coating resin. The obtained coating resin is preferably applied to the surface of the base film uniformly. From the viewpoint of having such excellent coatability, the viscosity of the coating resin is 15 mPa. s below is better, to 10mPa. s below is especially good. Here, the aforementioned viscosity is a value measured under a condition of 25 ° C using a tuning fork type vibrating viscometer. The viscosity can be adjusted by, for example, the ratio of the solvent and the particle diameter of the particles.

After the coating resin is obtained, the coating resin is applied onto the substrate film to form a film coated with the resin. At this time, the coating resin is usually directly provided on the surface of the base film without passing through other layers such as a layer of the adhesive. Further, the coating resin may be applied only to one side of the base film or may be applied to both surfaces. However, from the viewpoint of suppressing the production cost of the plurality of layers of the film, it is preferred to apply only the coating resin to one side of the base film.

When the coating resin is applied onto the substrate film, any coating method can be used. Specific coating methods include, for example, a bar coating method and a spray. Method, spin coating method, roll coating method, gravure coating method, pneumatic blade coating method, curtain flow coating method, slant plate coating method, extrusion coating method, and the like.

After the resin-coated film is formed on the base film, the film of the coating resin is cured and/or dried to obtain a resin layer. Usually, since the coating resin contains a solvent, the step of obtaining a resin layer includes drying and removing the solvent. The drying method is arbitrary, and can be carried out, for example, by any method such as drying under reduced pressure or heating and drying. In particular, from the viewpoint of allowing the reaction such as the crosslinking reaction to proceed rapidly in the coating resin, it is preferred to cure and dry the coating resin by heat drying. When heating and drying, the polymer is usually bonded to carry out a crosslinking reaction.

In the case where the coating resin is cured and dried by heating, the heating temperature is appropriately set to a range in which the solvent can be dried and the polymer component in the coating resin is cured. However, in the case where an extended film is used as the substrate film and it is not desired to change the hysteresis value exhibited by the substrate film, the heating temperature is preferably set at a temperature at which the substrate film does not cause alignment relaxation, specifically, When the glass transition temperature of the material forming the base film is Tg, it is preferably (Tg-30 ° C) or more, preferably (Tg - 10 ° C) or more, preferably (Tg + 60) or less, preferably. It is (Tg + 50 ° C) or less.

Further, the above-described production method may include any step other than the above steps. For example, the above-described production method may include a step of modifying the surface of the base film before forming a film coated with a resin on the base film. Thereby, the adhesion between the base film and the resin layer can be improved. Examples of the surface modification treatment of the base film include energy ray irradiation treatment and drug treatment. Examples of the energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, and the like. In terms of rate, etc., corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is particularly preferred. Further, as the drug treatment, for example, a saponification treatment can be mentioned. Further, as the drug treatment, for example, a method in which a base film is immersed in an aqueous oxidizing agent such as a potassium dichromate solution or concentrated sulfuric acid, followed by washing with water is mentioned.

Further, the above-described manufacturing method may include a step of performing a hydrophilization surface treatment on the surface of the protrusion having the resin layer. The surface of the protrusion having the resin layer is usually a bonding surface when the plurality of layers of the film are bonded to other members. Therefore, by further enhancing the hydrophilicity of the surface of the protrusion having the resin layer, the adhesion between the plurality of layers of the film and other members can be remarkably improved.

Examples of the hydrophilization surface treatment include corona discharge treatment, plasma treatment, saponification treatment, and ultraviolet irradiation treatment. In particular, in terms of processing efficiency, corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is preferred. Further, as the plasma treatment, it is preferred to treat the atmospheric piezoelectric slurry.

The resin layer can be formed on the base film by the above-described production method. As shown in Fig. 1, the surface 121 of the resin layer 120 which is obtained in this manner on the side opposite to the base film 110 has excellent slip properties because it has the projections 122. Therefore, the static friction coefficient of the surface 121 of the resin layer 120 opposite to the base film 110 and the surface 111 of the base film 110 opposite to the resin layer 120 can be reduced. The aforementioned static friction coefficient is preferably from 0.3 to 0.5. Thereby, when the plurality of layers of the film 100 are wound into a roll shape, the occurrence of convex defects can be effectively suppressed.

Moreover, the resin layer does not contain an internal haze which causes the resin layer A large amount of particles. Generally, particles having a small particle size have a small weight per one. Therefore, even if the amount on a weight basis is small, the number of particles can be increased. Therefore, by using particles having such a small particle diameter in combination with particles having a large particle diameter, the surface of the resin layer can form a large number of protrusions which are improved in the degree of slipperiness, but the amount of particles is made smaller. Therefore, the internal haze of the resin layer can be reduced.

The thickness of the resin layer is usually 10 nm or more, preferably 15 nm or more, preferably 20 nm or more, usually 100 nm or less, preferably 80 nm or less, and more preferably 70 nm or less. By setting the thickness of the resin layer to be equal to or higher than the lower limit of the above range, the mechanical strength of the resin layer can be improved. In addition, since it is possible to stably form the protrusions required on the surface of the resin layer by the upper limit or less, it is possible to effectively improve the slipperiness of the resin layer. Further, as described above, by making the thickness of the resin layer thin, it is generally possible to prevent the resin layer from easily affecting the optical characteristics of the base film. Therefore, since it is not necessary to change the configuration of the resin layer to adjust the optical characteristics of the plurality of layers of the film, the optical characteristics of the plurality of layers can be easily adjusted.

Further, the thickness of the resin layer is preferably 1 time or more, more preferably 2 times or more, particularly preferably 3 times or more, and 10 times or less with respect to the height of the highest frequency of the protrusion formed on the surface of the resin layer. Preferably, it is preferably 7 times or less, and particularly preferably 5 times or less. By setting the thickness of the resin layer to be equal to or higher than the lower limit of the above range, the haze value can be lowered. Moreover, by setting it as an upper limit or less, the film surface can provide sufficient smoothness which does not generate a surface defect.

The difference in refractive index between the substrate film and the resin layer is preferably 0.05 or less. When the refractive index difference is within the above range, light loss can be suppressed when the light is transmitted through the plurality of layers.

[4. Physical properties of multiple layers of film]

Since the plurality of layers of the film of the present invention are provided with the above-described resin layer, the smoothness of the side surface of the resin layer is high. Therefore, after winding up into a roll shape to form a film roll, occurrence of convex defects can be suppressed.

Further, since the plurality of layers of the film of the present invention have the resin layer having a small internal haze as described above, the internal haze can be reduced. Specifically, the internal haze of the plurality of layers of film is preferably 5% or less, preferably 3% or less, and particularly preferably 1% or less. Here, the internal haze of the plurality of layers of film can be measured by the following method.

A quartz light pipe having a height of 55 mm, a width of 36 mm, and an optical path length of 10 mm was prepared. The quartz light pipe is filled with polyoxygenated oil. A plurality of layers of the film were placed in the polyfluorene oxide oil to obtain a measurement sample. The internal haze of the plurality of layers of the film was measured by using the thus prepared measurement sample and by a haze meter.

Moreover, from the viewpoint of stably exhibiting the function as an optical film, it is preferred that the total light transmittance of the plurality of layers of the film is high. Specifically, the total light transmittance in terms of 1 mm thick is preferably 80% or more, and more preferably 90% or more. Here, the total light transmittance can be measured in accordance with JIS K0115 using a spectrophotometer (manufactured by JASCO Corporation, UV-Vis NIR spectrophotometer "V-570").

The plurality of layers of film may also be a retardation film having a hysteresis value in the in-plane direction or the thickness direction. The specific range of hysteresis values can be followed. Set for the use of a plurality of layers of film. When a specific range is exemplified, the hysteresis value Re in the in-plane direction is usually 10 nm to 500 nm, and the hysteresis value Rth in the thickness direction is appropriately selected from the range of -500 nm to 500 nm.

Further, the variation of the hysteresis value Re in the in-plane direction of the plurality of layers of film is usually within 10 nm, preferably within 5 nm, and more preferably within 2 nm. When the variation of the hysteresis value Re in the in-plane direction is within the above range, and when the plurality of layers of the film are used as the retardation film for a liquid crystal display device, the display quality can be improved. Here, the deviation of the hysteresis value Re in the in-plane direction is the maximum value and the minimum value of the hysteresis value Re in the in-plane direction when the hysteresis value Re in the in-plane direction when the light incident angle is 0° is measured in the width direction of the film. Here, the light incident angle 0 means a state in which incident light rays are orthogonal to the surface of the film.

The amount of the residual volatile component of the plurality of layers of film is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, still more preferably 0.02% by weight or less. By setting the amount of the volatile component to the above range, the dimensional stability is improved, and the hysteresis value Re in the in-plane direction of the plurality of layers of the film and the hysteresis value Rth in the thickness direction can be reduced with time.

The plurality of layers of the film may have a dimension in the width direction of, for example, 1000 mm to 3000 mm. Further, the size of the plurality of layers of the film in the longitudinal direction is not limited, and a long film is preferred. The term "long strip" as used herein refers to a length of at least 5 times or more with respect to the width of the film, preferably 10 times or more, and more specifically, it can be wound into a roll. The length of the degree of storage or handling.

[5. Method for manufacturing a plurality of layers of film]

The plurality of layers of the film of the present invention can be produced by a production method comprising the steps of: preparing a substrate film, and producing a resin layer on the prepared substrate film. Here, the step of producing a resin layer on the base film is as described above, and includes the steps of: obtaining a fluid-like coating resin; a step of coating a resin film on a base film to form a film coated with a resin; and a step of obtaining a resin layer by curing and/or drying the film of the coating resin formed on the base film. Therefore, the plurality of layers of the film can be produced by a manufacturing method including, for example, the following steps: a step of preparing a substrate film; and a step of mixing a plurality of particles having different average particle diameters and a binder polymer to obtain a fluid coating resin. a step of applying a coating resin onto a substrate film to form a film coated with a resin, and a step of curing and/or drying the film of the coating resin formed on the substrate film to obtain a resin layer.

Further, in the case where the plurality of layers of the film have any layer other than the base film and the resin layer, an arbitrary layer can be provided at any point in the production method of the plurality of layers of the film. However, the surface of the resin layer opposite to the base film is usually the outermost surface of the plurality of layers of film and exposed. Therefore, usually any layer is provided on the surface of the base film opposite to the resin layer.

Further, the step of extending the base film, the resin layer, and the plurality of layers of the film may be performed at any time in the method of producing the plurality of layers of the film. Further, a step of winding a plurality of layers of film into a roll shape may be performed.

[6. Use of multiple layers of film]

The plurality of layers of the film of the present invention are generally used as an optical film. When an example of an optical film used as a film of a plurality of layers is exemplified, a protective film, a retardation film, an optical compensation film, and the like are exemplified. In particular, the plurality of layers of the film of the present invention are preferably used as a retardation film or a polarizing plate protective film, and are particularly preferably used as a polarizing plate protective film.

The polarizing plate system usually has a polarizing mirror and a polarizing plate protective film. Therefore, when the plurality of layers of the film of the present invention are used as a polarizing plate protective film, usually The plurality of layers of the film of the present invention are bonded to a polarizer. At this time, a plurality of layers of the film are usually bonded to the polarizer on the side of the resin layer side of the plurality of layers of the film.

When the plurality of layers of the film are bonded to the polarizer, the plurality of layers of the film may be directly bonded to the polarizer without passing through the adhesive layer, or may be bonded through the adhesive layer. Moreover, only a plurality of layers of the film may be attached to one side of the polarizer, or may be bonded to both sides. When a plurality of layers of film are bonded to one surface of the polarizer, another film having high transparency may be attached to the other side of the polarizer.

The polarizer can be produced, for example, by adsorbing iodine or a dichroic dye on a polyvinyl alcohol film and then stretching it in a boric acid bath. Further, for example, a polyvinyl alcohol film can be adsorbed by iodine or a dichroic dye, and a part of the polyvinyl alcohol unit in the molecular chain can be modified into a polyvinylene unit. Further, as the polarizer, for example, a polarizer having a function of separating polarized light into reflected light and transmitted light can be used, such as a grid polarizer, a multilayer polarizer, or a cholesteric liquid crystal polarizer. Among these, a polarizer containing polyvinyl alcohol is preferred. The degree of polarization of the polarizer is preferably 98% or more, preferably 99% or more. The average thickness of the polarizer is preferably from 5 μm to 80 μm.

As an adhesive for adhering the polarizer to the plurality of layers of film, it is possible to use optically transparent ones. Examples of the adhesive include an aqueous adhesive, a solvent-based adhesive, a two-liquid curing adhesive, a photocurable adhesive, and a pressure-sensitive adhesive. Among them, an aqueous binder is preferred, and a polyvinyl alcohol-based aqueous binder is particularly preferred. Further, the adhesive may be used alone or in combination of two or more kinds in any ratio.

As the photocurable adhesive, for example, a urethane (meth) acrylate, a hydroxyalkyl (meth) acrylate, and an acrylamide derivative can be used. An acrylate based adhesive.

The urethane (meth) acrylate can be further reacted with a hydroxyl group-containing (meth)acrylic compound and, if necessary, a hydroxyl group-containing allyl ether compound, by reacting the polyisocyanate with a polyol, for example. It is obtained as an oligomer containing a radical polymerizable unsaturated group. Further, the urethane (meth) acrylate can be obtained, for example, by reacting a hydroxyl group-containing (meth)acrylic compound with a polyhydric alcohol and further reacting it with a polyisocyanate.

As the urethane (meth) acrylate, a urethane (meth) acrylate having a double bond of 2 to 3 per molecule and having an average molecular weight of 500 to 3,000 per one double bond can be used. It is preferable because it is easy to balance the strength, flexibility, photocurability, and viscosity.

The amount of the urethane (meth) acrylate in the photocurable adhesive is usually from 30% by weight to 50% by weight. By setting the amount of the urethane (meth) acrylate to be equal to or higher than the lower limit of the above range, it is possible to prevent the adhesive layer from becoming brittle. Further, by setting it to the upper limit or less, the viscosity of the adhesive can be reduced, and the adhesion strength can be improved.

Examples of the hydroxyalkyl (meth)acrylate include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Among these, hydroxyethyl methacrylate is particularly preferred.

The amount of the hydroxyalkyl (meth) acrylate in the photocurable adhesive is usually from 13% by weight to 40% by weight. When the amount of the hydroxyalkyl (meth)acrylate is at least the lower limit of the above range, the hydrophilicity of the entire adhesive can be improved, so that the adhesion strength to the polyvinyl alcohol-based polarizing film can be improved in particular. Further, by setting it to the upper limit or less, it is possible to prevent the adhesive layer from becoming brittle and to improve the photocurability of the adhesive.

Examples of the acrylamide derivative include N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-dimethylamineethylpropenamide, N,N. - dimethylaminopropyl acrylamide, N-isopropyl acrylamide, N,N-dimethylaminopropyl acrylamide, N-hydroxyethyl acrylamide. In particular, N,N-diethyl acrylamide, N-isopropyl acrylamide, N,N-dimethylaminopropyl acrylamide, and N-hydroxyethyl acrylamide are particularly preferred.

The amount of the acrylamide derivative in the photocurable adhesive is usually in the range of 0 to 30% by weight, preferably 1% by weight to 30% by weight.

The photocurable adhesive is preferably contained in an amount of 30% by weight to 40% by weight, based on the above components, of isobornyl (meth) acrylate. The heat resistance can be imparted to the adhesive layer by containing an isobornyl (meth) acrylate. Moreover, the viscosity for improving the coating performance can be adjusted without reducing the adhesion performance.

The photocurable adhesive is preferably a photopolymerization initiator. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, anthrone, and benzaldehyde. Anthraquinone, anthracene, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorodiphenyl ketone, 4,4'-dimethoxydiphenyl ketone, 4,4'-diaminodiyl Phenyl ketone, misch ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl Propane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2- Chlorothenoxone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholine-propan-1-one, 2,4,6-trimethylbenzhydryldiphenyl Phosphine oxide and the like. Further, the amount of the photopolymerization initiator in the photocurable adhesive is usually from 2% by weight to 10% by weight.

The viscosity of the subsequent agent is usually 20 mPa or more at 23 ° C, preferably 30 mPa or more, preferably 50 mPa or more, usually 5000 mPa or less, more preferably 3,000 mPa or less, or more preferably 1500 mPa or less.

The average thickness of the subsequent layer is preferably 0.05 μm or more, preferably 0.1 μm or more, more preferably 5 μm or less, and still more preferably 1 μm or less.

There is no limitation on the method of bonding the plurality of layers of film to the polarizer. For example, it is preferable to apply a bonding agent to one side of the polarizer, and then use a roll bonding machine to bond the polarizing film to the plurality of layers of film, and if necessary, dry or irradiate light such as ultraviolet rays.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples. However, the invention is not limited by the embodiments disclosed below.

In the following description, the "%", "ppm", and "part" of the quantity are the weight basis unless otherwise defined. Further, the following operations are carried out in a normal temperature and normal pressure atmosphere as long as it is not limited.

[Evaluation method]

[Method for measuring the height and number of protrusions]

The height and the number of the surface protrusions on the opposite side to the base film of the resin layer of the plurality of layers of the resin layer of the plurality of layers of the film were measured using a fine-shape measuring device ("ET4000M" manufactured by Otaru Laboratory) at a cut-off value of 0.8 mm and a measurement range of 1 mm × 1 mm. This measurement is performed in the central portion of the width direction of the plurality of layers of the film.

(Method for measuring internal haze)

A quartz light pipe having a height of 55 mm, a width of 36 mm, and an optical path length of 10 mm was prepared. Filling the quartz light pipe with polyoxygenated oil (TORAY.DOWCORNING) Company "SH710"). A plurality of layers of the film were placed in the polyphthalic acid oil to prepare a sample for measurement. The internal haze of the plurality of layers of the film was measured by using a measurement sample prepared in this manner and using a haze meter ("NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd.).

(Method for measuring peel strength)

(According to the manufacturing method of the agent)

66.5 g of pure water was weighed in a 100 g glass container. The pure water was warmed to 80 ° C and stirred with a stir bar. In this purely, 3.5 g of polyvinyl alcohol ("Gohsefimer Z200" manufactured by Nippon Synthetic Chemical Co., Ltd.) was added and completely dissolved to obtain a 5% polyvinyl alcohol solution, and then the polyvinyl alcohol solution was returned to room temperature. In the polyvinyl alcohol solution, 1% glyoxal was added as a crosslinking agent to the polyvinyl alcohol in the polyvinyl alcohol solution, and the mixture was sufficiently stirred to obtain an adhesive.

(Method of manufacturing polarizer)

A polyvinyl alcohol film having a thickness of 80 μm was dyed in a 0.3% aqueous solution of iodine. Subsequently, the dyed polyvinyl alcohol film was stretched to 5 times in an aqueous solution containing 4% of boric acid and 2% of potassium iodide, and dried at 50 ° C for 4 minutes to obtain a polarizer.

(Manufacture of polarizing plate)

The above-mentioned adhesive was applied to the surface of the resin layer side of the plurality of layers using a bar coater. A polarizer is placed on the adhesive layer, and a plurality of layers of the film are bonded to the polarizer by pressing with a roll bonding machine. Thereby, a polarizing plate including the polarizer, the adhesive layer, the resin layer, and the base film in this order was obtained.

(Measurement of peel strength)

The prepared polarizing plate was cut into a width of 10 mm to obtain a test piece. The surface of the film side of the test piece was made of an adhesive (No. manufactured by Nitto Denko Corporation). 5601") attached to the glass surface. Then, the polarizer of the test piece was clamped by the upper chuck of a precision universal testing machine ("AUTOGRAPH AGS-5kNG" manufactured by Shimadzu Corporation), and stretched in a direction perpendicular to the glass plate at a speed of 20 mm/min. . Peeling occurs at the interface between the resin layer and the base film by stretching the polarizer. At this time, the magnitude of the force for stretching the polarizer was measured. The measured value of the range of the strength measured in the longitudinal direction of the test piece was a stable 50 mm range, and the average value was set as the peeling strength.

[Method of evaluation of the appearance of the coil]

The appearance of the film roll obtained by winding a plurality of layers of film by 3000 m was evaluated by visual observation and palpation.

The concave portion of the film roll having no polygonal shape was evaluated as "good", and the concave portion having a polygonal shape on the circumferential surface of the film roll was designated as "poor".

[Evaluation method of multi-layer film surface state]

A sample was cut from a plurality of layers of film. Two linear polarizing plates were prepared, and the samples cut from the plurality of thin films were sandwiched by the linear polarizing plates. At this time, two linear polarizing plates were used as crossed Nicols and viewed from the thickness direction. The polarization transmission axes are made to be perpendicular to each other. Thereby, a laminated body provided with the linear polarizing plate, the sample, and the linear polarizing plate in this order was obtained.

The aforementioned laminate is inspected from the thickness direction. The light leakage portion is set as an optical defect and the number of optical defects is calculated. Here, the term “light leakage” refers to a portion of the light that can pass through the laminate. Further, the area of the sample used in the measurement was 100 m ² . The smaller the number of light leakage portions, the less wrinkles and folds are formed in the plurality of layers, and the surface state is good.

[Example 1]

(Manufacture of water-based resin)

In a reactor equipped with a thermometer, a stirrer, a nitrogen inlet pipe, and a cooling pipe, 840 parts of a polyester polyol ("MAXIMOL FSK-2000" manufactured by Kawasaki Chemical Co., Ltd.; a hydroxyl value of 56 mgKOH/g), 119 parts of toluene diisocyanate, and 200 parts of methyl ethyl ketone was allowed to react at 75 ° C for 1 hour while introducing nitrogen gas.

After completion of the reaction, the mixture was cooled to 60 ° C, and 35.6 parts of dimethylolpropionic acid was added thereto to carry out a reaction at 75 ° C. Thereby, a polyurethane solution containing an acid structure was obtained. The content of the isocyanate group (-NCO group) of the polyurethane contained in the solution was 0.5%.

Next, the polyurethane solution was cooled to 40 °C. In the cooled polyurethane solution, 1,500 parts of water and 120 parts of diterpene isophthalic acid (boiling point 224 ° C or more) of 120 parts (7 parts relative to 100 parts of polyurethane) were added as a nonvolatile base by using a homomixer ( Homomixer) High speed agitation for emulsification. Methyl ethyl ketone was distilled off from the emulsified liquid under heating and reduced pressure to obtain an aqueous dispersion of the neutralized polyurethane. The aqueous dispersion had a solid concentration of 40%.

Further, the aqueous dispersion of the polyurethane was separately obtained in an amount of 100 parts by weight of the polyurethane contained. In the aqueous dispersion of polyurethane obtained separately, 40 parts of glycerol polyepoxypropyl ether ("DENACOL EX-313" manufactured by NAGASE CHEMTEX Co., Ltd.; epoxy equivalent 141 g/eq) and an average particle diameter of 40 nm were prepared. 24 parts of cerium particles ("UFP-80" manufactured by Denki Kagaku Kogyo Co., Ltd.), 20 parts of cerium oxide particles ("SNOWTEX MP-2040" manufactured by Nissan Chemical Industries Co., Ltd.) having an average particle diameter of 200 nm, and 4 as a nonionic surfactant. Ethylene oxide adduct of 7-dihydroxy-2,4,7,9-tetramethyl-5-decyne ("SURFYNOL 465" manufactured by ACCESS Chemical Industry Co., Ltd.), and water, to obtain a solid content A 5% liquid aqueous resin is used as the urethane resin in an uncured state. Here, the amount of the nonionic surfactant added is set to be 100 ppm with respect to the obtained aqueous resin.

(Manufacture of multiple layers of film)

The pellet of the alicyclic olefin resin ("ZEONOR" manufactured by Zeon Corporation, Japan; glass transition temperature: 135 ° C) was dried at 70 ° C for 2 hours using a hot air dryer which circulated air. Subsequently, a T-die type film melt extrusion molding machine having a resin melt kneading machine having a 65 mm diameter screw and forming a molten resin temperature of 270 ° C and a T-shaped mold width of 500 mm was used. Under the conditions, a substrate film having a thickness of 100 μm and a length of 1000 m was prepared. The base film is a base film composed of an alicyclic olefin resin.

A discharge treatment was performed on one surface of the base film using a corona treatment device. The liquid aqueous resin described above was applied to a surface of the base film subjected to the discharge treatment so as to have a dry thickness of 50 nm using a roll coater to form a film of the aqueous resin. Subsequently, the film of the aqueous resin was cured and dried by heating at a temperature of 100 ° C for 60 seconds to form a resin layer on the base film. Thereby, a plurality of layers of a film including a base film and a resin layer were obtained. When the thickness of the resin layer of the obtained multilayer film was measured using a film thickness meter ("FE-300" manufactured by Otsuka Electronics Co., Ltd.), it was 50 nm.

The obtained multilayer film was evaluated by the above method.

[Examples 2 and 3 and Comparative Examples 1 to 4]

When the water-based resin was produced, the amount of the glycerol polyepoxypropyl ether of the epoxy compound, the amount of the cerium oxide particles having an average particle diameter of 40 nm, and the amount of the cerium oxide particles having an average particle diameter of 200 nm were changed as shown in Table 1. .

The manufacture and evaluation of the multilayer film were carried out in the same manner as in Example 1 except for the above.

[result]

The results of the examples and comparative examples are shown in the following table. In the following table, the meaning of the abbreviation is as follows.

The amount of large particles; the amount of cerium oxide particles having an average particle diameter of 200 nm.

Amount of small particles: the amount of cerium oxide particles having an average particle diameter of 40 nm.

Amount of epoxy: The amount of glycerol polyepoxypropyl ether.

[discuss]

From the results of the examples and the comparative examples, it was confirmed that the protrusions formed on the surface of the resin layer opposite to the base film were 3.5 ≦ G ≦ 7 in the plurality of layers including the base film and the resin layer. Further, N _B ≧N _C ≧N _D ≧N _E ≧N _{F is} satisfied, and when a film roll is wound up, convex defects can be suppressed, and internal haze can be reduced.

100‧‧‧Multilayer film

110‧‧‧Substrate film

111‧‧‧The surface of the base film opposite to the resin layer

120‧‧‧ resin layer

121‧‧‧Face of the resin layer opposite to the substrate film

122‧‧‧ Protrusion

Claims (12)

A multi-layer film comprising a base film and a plurality of film layers of a resin-containing resin layer provided on the base film, wherein the resin layer has a plurality of protrusions on a surface opposite to the base film; among the projections, (a) the height of the projection 5nm number per 1mm ² of the set number N _a / mm ^2, (b) the height of the projection 10nm per 1mm ² of the number N _B set number / mm ^2, ( c) the number of protrusions having a height of 15 nm per 1 mm ² is N _C / mm ² , (d) the number of protrusions having a height of 20 nm per 1 mm ² is N _D / mm ² , (e) the height is 25 nm ² the number of each of the protrusions is set to 1mm N _E number / mm ^2, (f) the height of the projection 30nm number per 1mm ² of the set number N _F / ² mm, the at G = N _a / N _F represents the value of G It is 3.5 ≦ G ≦ 7 and, N _B ≧ N _C ≧ N _D ≧ N _E ≧ N _F . The plurality of layers of the film according to claim 1, wherein the resin layer contains a polymer, and the polymer contains a polyurethane. The plurality of layers of the film according to claim 1, wherein the particles comprise a plurality of particles having different average particle diameters. The plurality of layers of the film according to claim 3, wherein the particles comprise: particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle diameter of 150 nm or more. The plurality of layers of the film according to claim 4, wherein the resin layer contains a polymer; and the particles (S) in the resin layer with respect to 100 parts by weight of the polymer The amount is 2 parts by weight or more and 24 parts by weight or less. The multi-layer film according to claim 4, wherein the resin layer contains a polymer; and the amount of the particles (L) in the resin layer is 5 parts by weight or more and 20 parts by weight based on 100 parts by weight of the polymer. Parts by weight or less. The plurality of layers of the film of claim 1, wherein the particles are cerium oxide. The plurality of layers of the film according to claim 1, wherein the resin layer has a thickness of 10 nm or more and 100 nm or less. The plurality of layers of the film according to claim 1, wherein the plurality of layers of the film are phase difference films. The plurality of layers of the film according to claim 1, wherein the plurality of layers of the film are polarizing plate protective films. A method for producing a plurality of layers of a film according to claim 1, comprising the steps of: mixing a plurality of particles having different average particle diameters and a polymer to obtain a fluid resin; and coating the resin in a fluid state a step of forming a film of the resin on a substrate film; and a step of curing and/or drying the film of the resin formed on the substrate film to obtain a resin layer. The method for producing a plurality of layers of a film according to claim 11, wherein the particles comprise particles (S) having an average particle diameter of less than 150 nm; and particles (L) having an average particle diameter of 150 nm or more.