JP2015179204A - Hard coat film, polarizing plate, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film which is sufficiently free from sticking to itself while being wound even when the thickness of the film is reduced, thereby preventing deterioration of visibility caused by flatness degradation and deformation of the film.SOLUTION: An optical film 12 has a first functional layer 22 including a hard coat layer on one surface of a film base material 21. A value expressed as A=(h1-h2)/hmax obtained from a fixed indentation depth loading-unloading test for the hard coat layer shall be 0.02-0.90, inclusive, where h1 represents a residual depth (μm) measured after 0 second of unloading holding time, h2 represents a residual depth (μm) after 60 seconds of unloading holding time, and hmax represents a preset indentation depth (μm). The optical film 12 satisfies at least one of the following conditions: (1) an arithmetic mean roughness Ra of a surface of the first functional layer 22 is 2 nm or more; and (2) an arithmetic mean roughness Ra of a surface of a second functional layer 23 formed on the other surface of the film base material 21 is 2 nm or more.

Description

  In the present invention, functional layers are respectively formed on both surfaces of a film base, and one of the functional layers includes a hard coat film including a hard coat layer, a polarizing plate having the hard coat film, and the polarizing plate. The present invention relates to an image display device having

  In recent years, a liquid crystal display device has attracted attention as one of image display devices. Liquid crystal display devices are widely used for monitors of personal computers and portable devices and television applications because they have various advantages such as being able to be reduced in size and thickness with low voltage and low power consumption. In order to prevent physical damage, an optical film having a hard coat layer on a film substrate (hereinafter referred to as a hard coat film) is used on the surface of the liquid crystal display device.

  Recently, with the advent of smartphones and the like, further miniaturization of liquid crystal display devices has been demanded. In order to cope with such downsizing, the hard coat film to be used is also required to have moldability. However, cracks may occur in the hard coat layer during molding, or the film may break in extreme cases. For this reason, as a hard coat film having moldability, a hard coat layer made of a self-healing material has attracted attention. The self-healing material is a material in which scratches rubbed by self-healing disappear after rubbing with a brass brush or the like, for example, and has a characteristic capable of self-healing elastic deformation. Specific examples of such self-healing materials are disclosed in Patent Documents 1 and 2, for example.

  Further, with the demand for miniaturization of liquid crystal display devices, there is an increasing demand for further thinning of members (optical films) constituting the liquid crystal display device such as hard coat films. The hard coat film is wound into a roll state after production, and is used for producing a polarizing plate by a roll-to-roll method, for example.

  However, when a hard coat film having a hard coat layer made of a self-healing material is wound in a roll state, there is a problem that the films are likely to stick to each other. In other words, even if an air layer is provided between the layers of the hard coat film wound in a roll shape, the air layer is compressed by the weight of the wound, and the hard coat film using the self-healing material does not use the self-healing material. Since the hard coat layer is softer than the normal hard coat film, the sticking between the films in the wound state is large, especially after the endurance test assuming long-term transportation, between the films wound in a roll shape The sticking was great. As a result, the flatness of the hard coat film using the self-healing material is likely to be deteriorated or distorted, and the visibility is remarkably deteriorated when the hard coat film is used in an image display device. Such deterioration in visibility leads to a reduction in commercial value and production yield as an image display device.

  For example, Patent Document 3 discloses a technique for preventing sticking of a roll film. In the technique disclosed in Patent Document 3, knurl portions (portions higher than the film surface) are formed at both ends in the width direction of the film, and a hard coat layer is formed between both knurl portions in the width direction. I am doing so. Both the knurled parts and the hard coat layer are formed by coating the curable composition using different coating systems. In this technique, sticking of films at the time of winding can be prevented by adjusting the bulkiness, width, and left / right balance of the knurled portion.

JP 2006-137780 A (see claim 1, paragraphs [0006], [0007], etc.) JP 2012-166356 A (see claim 1, paragraphs [0006], [0007], etc.) JP 2013-186456 A (refer to claim 1, paragraphs [0007], [0013], FIG. 1, etc.)

  However, in the technique of Patent Document 3, although the effect of improving the sticking prevention between the films at the time of winding is obtained, since the stiffness of the film becomes weaker as the film thickness becomes thinner, the sticking preventing effect is sufficiently obtained. It was difficult.

  The present invention has been made in order to solve the above-described problems, and the purpose thereof is sufficient to prevent the films from sticking to each other when wound into a roll even when the film thickness is reduced. A hard coat film capable of suppressing deterioration in visibility due to deterioration in flatness or distortion of the film when applied to an image display device, and a polarizing plate having the hard coat film Another object is to provide an image display device having the polarizing plate.

  The above object of the present invention is achieved by the following configurations.

1. A film base and a first functional layer formed on one surface of the film base;
The first functional layer includes a hard coat layer,
The following value A obtained by an indentation depth setting load-unloading test in which a test force is applied to the surface of the hard coat layer by a microhardness meter and pushed to a set depth and then unloaded is 0. 0.02 to 0.90,
A = (h1-h2) / hmax
However,
h1: Residual depth (μm) when measured with an unloading retention time of 0 seconds
h2: Residual depth (μm) when measured with an unloading holding time of 60 seconds
hmax: Setting push-in depth (μm)
And the hard coat film characterized by satisfying at least one of the following conditions (1) and (2).
(1) The arithmetic average roughness Ra of the surface of the first functional layer is 2 nm or more.
(2) It has a 2nd functional layer in the other side of the film base material, and arithmetic mean roughness Ra of the surface of the 2nd functional layer is 2 nm or more.

  2. 2. The hard coat film as described in 1 above, wherein the hard coat film has the second functional layer.

  3. The hard coat film as described in 1 or 2 above, wherein the value A is 0.20 or more and 0.90 or less.

  4). 4. The hard coat film according to any one of 1 to 3, wherein the arithmetic average roughness Ra of the surface of the first functional layer or the second functional layer is 10 nm or more.

  5. 5. The hard coat film as described in any one of 1 to 4 above, wherein the other surface of the film substrate or the second functional layer has a water contact angle of 95 ° or less.

  6). 6. The hard coat film as described in any one of 1 to 5 above, wherein the film substrate is a λ / 4 film.

  7). 7. The hard coat film as described in any one of 1 to 6 above, wherein the film substrate has a thickness of 1 μm or more and less than 30 μm.

8). Having a polarizer and a protective film formed on one surface of the polarizer;
The polarizing plate, wherein the protective film is the hard coat film according to any one of 1 to 7 above.

9. A display cell;
9. An image display device comprising the polarizing plate according to 8, which is disposed on the viewing side of the display cell.

  A first functional layer including a hard coat layer is formed on one surface of the film substrate. The value A obtained by the indentation depth setting load-unloading test for the hard coat layer is 0.02 or more and 0.90 or less, and this condition is satisfied when the hard coat layer contains a self-healing material. . In this configuration, (1) the arithmetic average roughness Ra of the surface of the first functional layer is 2 nm or more, and (2) the arithmetic average roughness of the surface of the second functional layer formed on the other surface of the film substrate. By satisfying at least one condition of Ra of 2 nm or more, the effect of preventing sticking between films when the hard coat film is rolled up can be sufficiently obtained, and a configuration using a self-healing material Even when the film thickness is reduced, the effect can be sufficiently obtained. Thereby, the flatness of the film can be prevented from being deteriorated or distorted due to the sticking of the film, so that even when the hard coat film of the present invention is applied to an image display device, the plane of the film It is possible to suppress the deterioration of visibility due to the deterioration of property and distortion.

1 is a cross-sectional view illustrating a schematic configuration of an image display device according to an embodiment of the present invention. It is sectional drawing which shows the detailed structure of the optical film of the visual recognition side with respect to the polarizer in the polarizing plate of the visual recognition side with respect to the liquid crystal cell of the said image display apparatus. It is sectional drawing which shows the other structure of the said optical film. It is sectional drawing which shows other structure of the said optical film. It is explanatory drawing which shows the curve obtained by an indentation depth setting load-unloading test. It is a top view which shows typically the structure of the outline of the manufacturing apparatus of the diagonally stretched film used by the said embodiment. It is a top view which shows typically an example of the rail pattern of the extending | stretching part of the said manufacturing apparatus.

  An embodiment of the present invention will be described below with reference to the drawings. In the present specification, when the numerical range is expressed as A to B, the numerical value range includes the values of the lower limit A and the upper limit B. The present invention is not limited to the following contents.

[Configuration of image display device]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image display device 1 according to the present embodiment. The image display device 1 includes a liquid crystal display panel 2 and a backlight 3. The backlight 3 is a light source for illuminating the liquid crystal display panel 2.

  The liquid crystal display panel 2 is configured by disposing polarizing plates 5 and 6 on both sides of a liquid crystal cell 4 (display cell) in which a liquid crystal layer is sandwiched between a pair of substrates. The polarizing plate 5 is attached to one surface side (for example, the viewing side) of the liquid crystal cell 4 via the adhesive layer 7. The polarizing plate 6 is attached to the other surface side (for example, the backlight 3 side) of the liquid crystal cell 4 via the adhesive layer 8. The driving method of the liquid crystal display panel 2 is not particularly limited, and various driving methods such as an IPS (In Plane Switching) type and a TN (Twisted Nematic) method can be employed.

  The polarizing plate 5 includes a polarizer 11 that transmits predetermined linearly polarized light, an optical film 12 as a surface protective film disposed on the viewing side of the polarizer 11, and a back surface disposed on the backlight 3 side of the polarizer 11. It is comprised with the optical film 13 as a protective film. The polarizing plate 6 includes a polarizer 14 that transmits predetermined linearly polarized light, an optical film 15 that is a surface protective film disposed on the viewing side of the polarizer 14, and a back surface that is disposed on the backlight 3 side of the polarizer 14. It is comprised with the optical film 16 as a protective film. The polarizer 11 and the polarizer 14 are arranged so as to be in a crossed Nicols state.

  FIG. 2 is a cross-sectional view showing a detailed configuration of the optical film 12 on the viewing side of the polarizing plate 5. The optical film 12 has a film base material 21, a first functional layer 22, and a second functional layer 23. The film substrate 21 is made of a cellulose ester film having a film thickness of 1 μm or more and less than 30 μm, for example. The first functional layer 22 is formed on one surface of the film substrate 21, that is, the surface on the viewing side, and here, it is composed of a single hard coat layer. Therefore, the optical film 12 provided with such a hard coat layer constitutes a hard coat film. In the present embodiment, the hard coat layer is composed of a layer containing a self-healing material (a material having self-healing properties), and details thereof will be described later. The second functional layer 23 is a so-called back coat layer, and here is an anti-blocking layer having a surface arithmetic average roughness Ra of 2 nm or more.

  FIG. 3 is a cross-sectional view showing another configuration of the optical film 12. The optical film 12 has a configuration in which a functional layer is formed only on one surface of the film substrate 21, that is, a first functional layer 22 is formed on one surface of the film substrate 21, and a first layer is formed on the other surface. The bifunctional layer 23 may not be formed. In this case, by setting the arithmetic average roughness Ra of the surface of the first functional layer 22 to 2 nm or more, the first functional layer 22 can have both self-healing characteristics and anti-blocking characteristics.

  FIG. 4 is a cross-sectional view showing still another configuration of the optical film 12. As shown in the figure, the first functional layer 22 may be configured by laminating a plurality of hard coat layers 22a and 22b. In this case, at least the hard coat layer 22b on the most visible side only needs to contain a self-healing material.

  The film base 21 of the optical film 12 may be composed of a λ / 4 film. The λ / 4 film is a layer that imparts an in-plane retardation of about ¼ of the wavelength to transmitted light, and is composed of, for example, a cellulose ester film that has been subjected to oblique stretching described below. The angle (crossing angle) formed between the slow axis of the λ / 4 film and the absorption axis of the polarizer 11 is 30 ° to 60 °, whereby the linearly polarized light from the polarizer 11 is converted into the λ / 4 film ( It is converted into circularly polarized light or elliptically polarized light by the film substrate 21).

  Therefore, when an observer wears polarized sunglasses and observes a display image, the polarizing plate can be used regardless of how the transmission axis of the polarizer 11 (perpendicular to the absorption axis) and the transmission axis of the polarized sunglasses are misaligned. The light component parallel to the transmission axis of the polarized sunglasses contained in the light emitted from 5 (circularly polarized light or elliptically polarized light) can be guided to the eyes of the observer. Thereby, it can suppress that it becomes difficult to see a display image with the angle to observe. In addition, even when the observer does not wear polarized sunglasses, since it is circularly polarized light or elliptically polarized light that is emitted from the polarizing plate 5 and incident on the observer's eyes, linearly polarized light is directly incident on the observer's eyes. Compared to the above, the burden on the eyes of the observer can be reduced.

  Moreover, about the optical films 13, 15, and 16 as a surface protection film, base films, such as a cellulose-ester film mentioned later, are generally used.

  Hereinafter, the details of the hard coat film will be described.

[First functional layer]
The first functional layer is obtained by an indentation depth setting load-unloading test in which a test force is applied to the surface of the hard coat layer with a micro hardness tester, the indentation is pushed to a set depth, and then unloaded. The value A is 0.02 or more and 0.90 or less.
A = (h1-h2) / hmax
However,
h1: Residual depth (μm) when measured with an unloading retention time of 0 seconds
h2: Residual depth (μm) when measured with an unloading holding time of 60 seconds
hmax: Setting push-in depth (μm)

  The unloading holding time of 0 seconds refers to the time when the loaded test force becomes 0 mN due to unloading, and the unloading holding time of 60 seconds refers to the time from when the loaded test force becomes 0 mN due to unloading. The time when 60 seconds have passed. By the indentation depth setting load-unloading test, a load test force-indentation depth curve showing the relationship between the loaded test force and the indentation depth, for example, as shown in FIG. 5 is obtained. FIG. 5 shows h1, h2, and hmax described above together.

  When the self-healing material is contained in the hard coat layer, a value within the above range is obtained as the value of A. From the viewpoint of reliably imparting self-healing characteristics to the first functional layer, the value A is desirably 0.20 or more and 0.90 or less.

(resin)
As a preferable resin constituting the first functional layer, a polyurethane resin can be exemplified. As the polyurethane-based resin, a thermosetting polyurethane resin or a thermoplastic polyurethane resin can be used. The thermosetting polyurethane resin is a polyurethane resin obtained by using a compound having 3 or more functional groups as at least a part of the raw material composed of polyols and polyisocyanate. The thermoplastic polyurethane resin is a polyurethane resin obtained using only a compound having 2 functional groups.

  Examples of the polyols used as the raw material for the polyurethane resin include polyether polyols, polyester polyols, polycarbonate polyols, and the like. Among these, a polyester-based polyol having an excellent balance between strength and self-healing property is preferable, and a polyester-based polyol obtained by opening a cyclic ester (particularly caprolactone) is particularly preferable. The number of functional groups of the polyol is preferably 2 to 3 from the viewpoint of strength and self-healing properties. The polyols are preferably triol alone, a mixture of two or more triols, or a mixture of triol and diol.

  The polyols may contain a chain extender. Examples of the chain extender include short chain polyols and short chain polyamines. Among these, a short chain polyol is preferable from the viewpoint of transparency, flexibility, and reactivity, and a short chain diol is particularly preferable. Although the hydroxyl value of the said polyols is not specifically limited, As an average hydroxyl value in raw material polyol, 100-600 are preferable and 200-500 are more preferable. The average hydroxyl value is an average hydroxyl value calculated including a chain extender.

  As the polyisocyanate used as a raw material for the polyurethane-based resin, a non-yellowing polyisocyanate having durable yellowing is preferable. The non-yellowing polyisocyanate is a polyisocyanate that does not have an isocyanate group directly bonded to an aromatic nucleus, and specific examples thereof include hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. The raw materials for the polyurethane resin may be used alone or in combination. Moreover, additives such as stabilizers such as antioxidants and light stabilizers, urethanization catalysts, colorants, flame retardants, antistatic agents, surfactants and silane coupling agents may be added as necessary. .

  The first functional layer is also preferably composed of an actinic radiation curable resin. As the active ray curable resin, an active energy ray curable resin having an epoxy skeleton, or an active energy ray curable resin having an alkyl chain skeleton or an alkylene oxide skeleton is preferable because self-healing properties are easily exhibited. The epoxy (meth) acrylate is obtained by reacting a tricarboxylic acid represented by (A) or (B) with a (meth) acrylate having a monooxirane ring represented by the following (C) or (D). is there.

  The tricarboxylic acid represented by (A) and the tricarboxylic acid represented by (B) can be used alone or in combination. The (meth) acrylate having a monooxirane ring represented by (C) and the (meth) acrylate having a monooxirane ring represented by (D) can be used alone or in combination.

ただし、Ｒは水素（Ｈ）又は水酸基（ＯＨ）、ａ、ｂ及びｄは０〜８の整数、ｃは０〜９の整数で、０≦ａ＋ｂ＋ｃ＋ｄ≦９かつ〔ａ＜ｄ又は（ａ＝ｄかつｂ≦ｃ）〕である。 (A): Aliphatic tricarboxylic acid represented by the following general formula (1)

However, R is hydrogen (H) or a hydroxyl group (OH), a, b, and d are integers of 0-8, c is an integer of 0-9, and 0 ≦ a + b + c + d ≦ 9 and [a <d or (a = d And b ≦ c)].

  (B): Trimellitic acid

ただし、Ｒは水素又はメチル基、ｎは１〜５の整数、ｍは１〜３の整数を表す。 (C): Aliphatic (meth) acrylate having a monooxirane ring represented by the following general formula (2)

However, R represents hydrogen or a methyl group, n represents an integer of 1 to 5, and m represents an integer of 1 to 3.

ただし、Ｒは水素又はメチル基、ｓは１〜１０の整数を表す。 (D): An alicyclic (meth) acrylate having a monooxirane ring represented by the following general formula (3)

However, R represents hydrogen or a methyl group, and s represents an integer of 1 to 10.

  Epoxy (meth) acrylate has a good balance between the soft segment and the hard segment, and it is easy to obtain characteristics that easily relieve shrinkage stress.

  As the tricarboxylic acid of (A), 1,2,4-butanetricarboxylic acid (R is hydrogen, a = 0, b = 0, c = 1 and d = 0), 1,3,5-hexanetricarboxylic acid ( R is hydrogen, a = 0, b = 1, c = 2 and d = 0), 1,2,4-pentanetricarboxylic acid (R is hydrogen, a = 0, b = 0, c = 1 and d = 1) ), 1,2,5-pentanetricarboxylic acid (R is hydrogen, a = 0, b = 0, c = 2 and d = 0), 1,3,4-pentanetricarboxylic acid (R is hydrogen, a = 0 B = 1, c = 0 and d = 1), 1,2,5-pentanetricarboxylic acid (R is hydrogen, a = 0, b = 1, c = 1 and d = 0), 1,2,6 -Hexanetricarboxylic acid (R is hydrogen, a = 0, b = 0, c = 3 and d = 0), 1,2,4-hexanetricarboxylic acid (R is hydrogen, a = 0, b = 0, = 1 and d = 2), 1,4,5-hexanetricarboxylic acid (R is hydrogen, a = 0, b = 2, c = 0 and d = 1), 1,3,4-hexanetricarboxylic acid (R Is hydrogen, a = 0, b = 1, c = 0 and d = 2), 1,3,6-hexanetricarboxylic acid (R is hydrogen, a = 0, b = 1, c = 2 and d = 0) 2,3,5-hexanetricarboxylic acid (R is hydrogen, a = 1, b = 0, c = 1 and d = 1), 1,4,8-octanetricarboxylic acid (R is hydrogen, a = 0, b = 2, c = 3 and d = 0), 1,5,10-nonanetricarboxylic acid (R is hydrogen, a = 0, b = 3, c = 3 and d = 0), 1,6,12- Dodecane tricarboxylic acid (R is hydrogen, a = 0, b = 4, c = 5 and d = 0), citric acid (R is a hydroxyl group, a = b = c = d = 0), and the like.

  Examples of trimellitic acid (B) include 1,3,5-trimellitic acid and 1,2,3-trimellitic acid in addition to 1,2,4-trimellitic acid.

  As the aliphatic (meth) acrylate having a monooxirane ring of (C), 4-hydroxybutyl acrylate monoglycidyl ether [4-HBAGE, a compound in which n = 4 and m = 1 in the general formula (2)], 2- And hydroxyethyl acrylate monoglycidyl ether [2-HEAGE, a compound where n = 2 and m = 1 in the general formula (2)].

  Examples of the alicyclic (meth) acrylate having a monooxirane ring represented by the general formula (3) in (D) include alicyclic epoxy group-containing acrylate (s = 6).

  A synthesis example is given below. In a four-necked flask equipped with a stirrer, a thermometer and a condenser, 415.8 parts by mass of toluene, 100 parts by mass of 1,2,4-butanetricarboxylic acid (acid value: 886), 4-hydroxybutyl acrylate monoglycidyl ether [Japan Kasei Co., Ltd., 4-HBAGE] 315.8 parts by mass and hydroquinone monomethyl ether 0.1 parts by mass were charged and heated to 100 ° C. Thereafter, it was confirmed that 1,2,4-tricarboxylic acid was completely dissolved, 2 parts by mass of TPP (triphenylphosphine) was charged, and kept at the same temperature for 24 hours to complete the reaction. As a result, an epoxy acrylate having a solid content of 50% by mass and an acid value of 4.2 mgKOH / g (in terms of solid content) was obtained. The yield was 96.1%.

  As an active energy ray-curable resin having an alkyl chain skeleton or an alkylene oxide skeleton, for example, a (meth) acrylate having 1 hydroxyl group and 3 or more (meth) acryloyl groups in the molecule has 2 to 4 carbon atoms. Mention may be made of urethane (meth) acrylate (A) obtained by reacting (meth) acrylate (a-1) obtained by adding 1 to 20 mol of alkylene oxide with polyisocyanate (a-2). .

  Examples of the (meth) acrylate having one hydroxyl group and three or more (meth) acryloyl groups in the molecule include pentaerythritol tri (meth) acrylate, diglycerin tri (meth) acrylate, and ditrimethylolpropane tri (meth) acrylate. Xylitol tetra (meth) acrylate, triglycerin tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, sorbitol penta (meth) acrylate, and the like.

  Among these, (meth) acrylate having one hydroxyl group and 3 to 5 (meth) acryloyl groups in the molecule is preferable, and pentaerythritol tri (meth) acrylate, xylitol tetra (meth) acrylate, triglycerin tetra ( And (meth) acrylate and dipentaerythritol penta (meth) acrylate. More preferred are pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.

  As a kind of alkylene oxide used for addition polymerization, a C2-C4 alkylene oxide can be used. Specific examples include ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran and the like. These alkylene oxides may be used alone or in combination of two or more. When two or more of these alkylene oxides are used in combination, they may be subjected to addition polymerization in a random or block form. Of these, tetrahydrofuran is preferable, and the average added mole number of alkylene oxide is 1 to 20, and preferably 2 to 12.

  (A-1) As a manufacturing method of a component, it can carry out by the method similar to normal ring-opening polymerization. For example, after charging a reaction vessel with (meth) acrylate and catalyst having one hydroxyl group and three or more (meth) acryloyl groups in the molecule, a polymerization inhibitor and an organic solvent as necessary, Substitution with an inert gas such as nitrogen gas, and alkylene oxide is injected to effect addition polymerization. As reaction temperature, it is -30-120 degreeC normally, Preferably it is 0-80 degreeC, More preferably, it is 20-60 degreeC. When it is lower than −30 ° C., the reaction rate is slow, and when it is higher than 120 ° C., side reaction or polymerization may proceed excessively or the product may be colored. The reaction time is usually 0.3 to 20 hours, more preferably 1 to 10 hours.

  The polyisocyanate (a-2) is an aliphatic, alicyclic or aromatic isocyanate containing at least two isocyanate groups in the molecule. Specific examples of the bifunctional isocyanate include 1,4-tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,5-naphthalene diisocyanate, 4, Aliphatic and alicyclic diisocyanates such as aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate. Specific examples of the trifunctional isocyanate include 1,4-tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone. Isocyanurate modified by isocyanurate modification by polycondensation of diisocyanates such as diisocyanate and norbornane diisocyanate, adduct modified by adduct modification of the diisocyanate, biuret modified by diuret and trihydric alcohols such as glycerin and trimethylolpropane The body is mentioned. Specific examples of the polyfunctional isocyanate include isocyanate compounds obtained by reacting the diisocyanate with a polyol or polyamine.

  Among these, trifunctional isocyanate modified by polycondensation of aliphatic diisocyanate and alicyclic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate monomer is preferable, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate. More preferred are aliphatic and cycloaliphatic diisocyanates and isocyanurate-modified trifunctional isocyanates of these diisocyanates. These polyisocyanates may be used alone or in combination of two or more. The urethane (meth) acrylate (A) usually has 4 to 15, preferably 6 to 12 (meth) acryloyl groups in the molecule. The number of urethane bond groups and (meth) acryloyl groups in the molecule is preferred.

  A synthesis example is given below. In a stainless steel autoclave equipped with a stirrer, a thermometer, and a pressure gauge, a mixture of pentaerythritol triacrylate (hereinafter referred to as “PE3A”) / pentaerythritol tetraacrylate (hereinafter referred to as “PE4A”) (mass ratio of 70/30). 307 parts by mass of a mixture, hydroxyl value: 137 mg KOH / g), 0.1 part by mass of hydroquinone monomethyl ether, and 3.2 parts by mass of tin tetrachloride were added, and the inside of the reaction system was replaced with nitrogen gas. Next, 100 parts by mass of ethylene oxide (hereinafter referred to as “EO”) was introduced over 3 hours while maintaining the gauge pressure at 0.1 to 0.3 MPa at 45 ° C., and reacted at the same temperature for 2 hours. Continued. Furthermore, after decompressing at 45 degreeC and hold | maintaining for 30 minutes, 402 mass parts of viscous liquids were obtained by returning and cooling to a normal pressure. Thereafter, an adsorbent (KYOWARD 1000: manufactured by Kyowa Chemical Industry Co., Ltd.) was added and stirred at 70 ° C. while blowing air, and then the adsorbent was filtered to obtain 370 parts of a viscous liquid. It was. The resulting viscous liquid has a hydroxyl value of 106 mgKOH / g. When calculated from the hydroxyl value, 3 moles of EO is added to PE3A to obtain a (meth) acrylate having a number average molecular weight of 430, and an EO3 mole adduct of PE3A The mass ratio of the / PE4A mixture was 77/23.

  In addition to the above-described resins, the actinic radiation curable resin includes an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable resin, which will be described later, used for the second functional layer. An epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, an ultraviolet curable epoxy resin, or the like can also be used. These actinic radiation curable resins may be used alone or in combination, and may be used in combination with other resins such as the polyurethane-based resin.

  Commercially available products of active energy ray-curable resins include, for example, AUP-787 and AUP-727 manufactured by Tokushi Co., Ltd., Pandex GW series manufactured by DIC Corporation, and YS-112 manufactured by NATCO Corporation (trade name, polydimethyl Preferable examples include siloxane graft acrylate paints.

  The first functional layer may contain a polyisocyanate compound (A). As the polyisocyanate compound (A), an adduct polyisocyanate compound (a1) obtained by reacting an aliphatic diisocyanate monomer and a polyol is preferable.

  Examples of the diisocyanate monomer used in the production of the adduct type polyisocyanate compound (a1) and the nurate type polyisocyanate compound (a2) include butane-1,4-diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate. 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate and the like. These may be used alone or in combination of two or more.

  Among the aliphatic diisocyanate monomers, linear aliphatic diisocyanate monomers such as butane-1,4 diisocyanate and hexamethylene diisocyanate are preferable, and hexamethylene diisocyanate is particularly preferable, from the balance between flexibility and toughness. The adduct type polyisocyanate compound (a1) is obtained by reacting an aliphatic diisocyanate monomer with a polyol. The reaction can be carried out within a temperature range of 20 to 120 ° C. under solvent-free conditions or in various organic solvents that are non-reactive with isocyanate groups and hydroxyl groups, such as toluene and xylene. Moreover, various urethanization catalysts can be used as needed.

  The polyol used in the production of the adduct type polyisocyanate (a1) is a compound having two or more hydroxyl groups in the molecule. Specific examples include aliphatic polyols such as 1,3-butanediol, trimethylolpropane, and 2,2,4-trimethyl-1,3-pentanediol.

(Photopolymerization initiator)
The first functional layer preferably contains a photopolymerization initiator to accelerate the curing of the actinic radiation curable resin. The content of the photopolymerization initiator is preferably a mass ratio such that photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto. It is not something. Commercially available products may be used as the photopolymerization initiator, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

(Surface shape)
The first functional layer may have surface irregularities. When the surface has irregularities, the arithmetic average roughness Ra (JIS B0601: 2001) is 2 nm or more, more preferably 10 nm or more, and further preferably in the range of 10 nm to 5 μm. Excellent anti-blocking properties. The arithmetic average roughness Ra is a value measured with an optical interference type surface roughness meter (manufactured by ZYGO, NewView) according to JIS B0601: 2001. The formation method of the surface unevenness | corrugation of a 1st functional layer can be formed by the surface unevenness formation method of the 2nd functional layer mentioned later. The first functional layer preferably has a water contact angle of 95 ° or less. The contact angle with water can be measured by the method described later.

[Second functional layer]
A 2nd functional layer is a layer formed in the other surface with the 1st functional layer of a base film, and is a layer which specifically has surface unevenness | corrugation. As the height of the surface irregularities, the arithmetic average roughness Ra (JIS B0601: 2001) is 2 nm or more, more preferably 10 nm or more, and further preferably in the range of 10 nm to 5 μm. Demonstrate sex. The arithmetic average roughness Ra is a value measured with an optical interference type surface roughness meter (manufactured by ZYGO, NewView) according to JIS B0601: 2001.

  Thus, antiblocking property expresses because the 2nd functional layer has arithmetic mean roughness Ra2nm or more, and the adhesion prevention effect of films when winding a hard coat film in roll shape is enough. Even when the thickness of the film substrate is reduced by the configuration using the self-healing material for the first functional layer, the effect can be sufficiently obtained. As a result, it is possible to suppress the deterioration of the flatness of the film due to the sticking of the film or the occurrence of distortion, so even when the hard coat film of this embodiment is applied to an image display device, It is possible to suppress deterioration in visibility due to deterioration in flatness and distortion. In particular, when the thickness of the film base material of the hard coat film is 1 μm or more and less than 30 μm, the above effect is very effective.

  Moreover, when forming the knurl part of the both ends of the width direction of a film and the hard coat layer between them using the coating machine of a different coating system like the past, the film thickness (height) of a knurl part Is difficult to control with a coating machine, and a plurality of coating machines are required, so the productivity of the film decreases. However, in this embodiment, since the anti-blocking property is exhibited by controlling the surface roughness of the second functional layer, it is possible to avoid a decrease in film productivity due to the formation of the knurled portion.

  As for the surface irregularities of the second functional layer, a method of forming protrusions on the surface by pressing a mold, a method of imparting surface irregularities by dispersing fine particles in the resin layer forming the second functional layer, spinodal decomposition It can be formed by a method of forming surface irregularities by phase separation by, for example.

  The second functional layer preferably has a water contact angle of 95 ° or less. Since the second functional layer has hydrophilicity with a water contact angle of 95 ° or less, the second functional layer and the first functional layer are difficult to stick even when the film is wound into a roll. The effects of the present embodiment that suppress the deterioration in flatness and distortion of the film due to the above-described film sticking are easily obtained. In addition, when not forming a 2nd functional layer in the other surface of a film base material, the same effect as the above can be acquired if the water contact angle of the said other surface is 95 degrees or less.

(resin)
The second functional layer is a layer composed mainly of a resin. Specifically, it is preferable to contain an actinic radiation curable resin from the viewpoint of excellent mechanical film strength. That is, it is a layer mainly composed of a resin that is cured through a crosslinking reaction by irradiation with active rays (also called active energy rays) such as ultraviolet rays and electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The

  Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin curable by ultraviolet irradiation is particularly excellent in mechanical film strength (abrasion resistance, pencil hardness). It is preferable from the point. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin. A curable epoxy resin or the like is preferably used, and an ultraviolet curable acrylate resin is particularly preferable.

  As the ultraviolet curable acrylate resin, a polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate.

  Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Preferred examples include erythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, active energy ray-curable isocyanurate derivatives, and polybasic acidic acrylates. It is done.

  Commercially available polybasic acrylates include dipentaerythritol pentaacrylate succinic acid modification, pentaerythritol triacrylate succinic acid modification, dipentaerythritol pentaacrylate phthalic acid modification, pentaerythritol triacrylate phthalic acid modification, polybasic Examples include acid-modified acrylic oligomers. Examples of commercially available products include Aronix M-510, Aronix M-520 (manufactured by Toagosei Co., Ltd.), DPE6A-MS, PE3A-MP, DPE6A-MP, PE3A-MP (manufactured by Kyoeisha Chemical Co., Ltd.) and the like. Moreover, as content, when the resin component which forms a functional layer film | membrane is set to 100, it is preferable to contain 30% or more by mass ratio, More preferably, it is preferable to contain 50% or more. Other commercially available resins include Adekaoptomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (Sanyo Chemical Industries, Ltd.) Manufactured), Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.), NK-Ester A-TMM -3L, NK-ester AD-TMP, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (Shin Nakamura Chemical Co., Ltd.), PE-3A (Kyoeisha Chemical) etc. are mentioned. You may mix the said active ray curable resin individually or in mixture of 2 or more types.

  A monofunctional acrylate may be used. Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

  When using monofunctional acrylate, it is preferable to contain these so that the content of polyfunctional acrylate and monofunctional acrylate may be polyfunctional acrylate: monofunctional acrylate = 80: 20 to 98: 2 in mass ratio. .

(Photopolymerization initiator)
The second functional layer preferably contains a photopolymerization initiator to accelerate the curing of the actinic radiation curable resin. The content of the photopolymerization initiator is preferably a mass ratio such that photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto. It is not something. Commercially available products may be used as the photopolymerization initiator, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

(Surface unevenness formation)
<Polymer silane coupling agent coated fine particles>
The second functional layer preferably contains fine particles coated with a polymer silane coupling agent from the viewpoint of forming surface irregularities and exhibiting excellent antiblocking properties. The content of the fine particles is preferably a mass ratio such that the polymer silane coupling agent-coated fine particles: active ray curable resin = 0.1: 100 to 100: 100.

  Although it does not restrict | limit especially as microparticles | fine-particles coat | covered with a polymer silane coupling agent, A silica, an alumina, a zirconia, a titanium oxide, an antimony pentoxide etc. are mentioned, Preferably it is a silica. The silica fine particles may be hollow particles having cavities inside.

<Polymer silane coupling agent>
The polymer silane coupling agent refers to a reaction product of a polymerizable monomer and a silane coupling agent (silane compound). Such a polymer silane coupling agent can be obtained, for example, according to the method for producing a reaction product of a polymerizable monomer and a reactive silane compound disclosed in JP-A-11-116240.

  Specific examples of the polymerizable monomer include (meth) acrylic acid, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) -N-butyl, isobutyl (meth) acrylate, (meth) acrylic acid-n-hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-n-heptyl, (meth) acrylic acid-n-octyl, ( 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate , (Meth) acrylic acid-2-methoxyethyl, (meth) acrylic acid-3-methoxybutyl, (meth) acrylic acid-2 Hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, stearyl (meth) acrylate, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, ethylene oxide adduct of (meth) acrylic acid, ( Trifluoromethylmethyl (meth) acrylate, 2-trifluoromethylethyl (meth) acrylate, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate , 2-perfluoroethyl (meth) acrylate, perfluoromethyl (meth) acrylate, diverfluoromethyl methyl (meth) acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl (meth) acrylate, ( (Meth) acrylic acid 2-perfluorohexylethyl, (Meth) acrylic acid monomers such as 2-perfluorodecylethyl (meth) acrylate and 2-perfluorohexadecylethyl (meth) acrylate; styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and the like Styrene monomers such as salts; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleic acid, malein Monoalkyl and dialkyl esters of acids; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmale Nitrile group-containing vinyl monomers such as amide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide; amide group-containing vinyl monomers such as acrylamide and methacrylamide; vinyl acetate, vinyl propionate, vinyl pivalate, benzoate Vinyl esters such as vinyl acid and vinyl cinnamate; Alkenes such as ethylene and propylene; Conjugated dienes such as butadiene and isoprene; Vinyl chloride, vinylidene chloride, allyl chloride, allyl alcohol, acrylic resin monomers; Pentaerythritol triacrylate , Pentaerythritol tetraacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetraacrylate, ditrimethylolpropante La (meth) acrylate, dipentaerythritol hexaacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl acrylate, n-stearyl acrylate, 1,6 -Hexanediol dimethacrylate, perfluorooctylethyl methacrylate, trifluoroethyl methacrylate, urethane acrylate and the like, and mixtures thereof.

  Polymers (oligomers and prepolymers) of these polymerizable monomers can also be used. These polymerizable monomers may be used alone or in combination. (Meth) acryl means acryl or methacryl, and (meth) acrylate means acrylate or methacrylate.

As the reactive silane compound, an organosilicon compound represented by the following formula (4) is preferably used.
X-R-Si (OR) ₃ (4)
(In the formula, R represents an organic group having 1 to 10 carbon atoms selected from a substituted or unsubstituted hydrocarbon group. X represents a (meth) acryloyl group, an epoxy group (glycid group), a urethane group, an amino group, Represents one or more functional groups selected from fluoro groups.)

  Specifically, as the organosilicon compound represented by the formula (4), 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) Propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxy Run, γ- (meth) acrylooxymethyltrioxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyl Trimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, 3-ureidoisopropylpropyltriethoxy Silane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane Emissions, N-beta (aminoethyl) .gamma.-aminopropyltrimethoxysilane, N- phenyl--γ- aminopropyltrimethoxysilane, and the like and mixtures thereof.

  A polymeric silane coupling agent is prepared by reacting a polymerizable monomer and a reactive silane compound. Specifically, an organic solvent solution in which a reactive silane compound is mixed in an amount of 0.5 to 20 parts by weight and further 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer is prepared, and polymerization is started. It can be obtained by adding an agent and heating.

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate and ethylene glycol monomethyl ether, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ethers such as tetrahydrofuran and dioxane. , Alcohols such as methanol and isopropanol, and halogenated hydrocarbons such as chloroform. These can also be mixed and used. In this case, the total concentration of the polymerizable monomer and the reactive silane compound is preferably in the range of 1 to 40% by weight, more preferably 2 to 30% by weight as the solid content.

  Polymerization initiators are azoisobutyl nitrile, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexinoate, t-butylperoxyisobutyrate, t-butyl. Peroxide polymerization initiators such as peroxypivalate, t-butylperoxybenzoate, t-butylperoxyacetate, 2,2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvalero) Nitriles) and azo compounds such as 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile). The reaction temperature is desirably in the range of 30 to 100 ° C, more preferably 50 to 95 ° C. If the reaction temperature is low, the reaction is slow and it may take too much time to prepare a polymer silane coupling agent with a large molecular weight. On the other hand, if the reaction temperature is too high, the reaction rate will be too high and the desired molecular weight will be May not be able to be controlled. The molecular weight of the polymer silane coupling agent is preferably in the range of 2,500 to 150,000, more preferably 2,000 to 100,000 in terms of polystyrene.

  The thickness of the coating layer of the polymer silane coupling agent is preferably in the range of 1 to 10 nm, more preferably 1 to 5 nm. If the coating layer is thin, dispersibility of the fine particles in the matrix component may be insufficient. Moreover, when the coating layer is too thick, there is a problem that productivity is lowered.

  Further, the content of the coating layer in the polymer silane coupling agent-coated fine particles is preferably in the range of 0.5 to 20% by weight, more preferably 1 to 15% by weight as the solid content.

<Method for preparing polymer silane coupling agent-coated fine particles>
Specifically, the polymer silane coupling-coated fine particles can be prepared by adding a polymer silane coupling agent to a fine particle organic solvent dispersion and coating the fine particles with the polymer silane coupling agent in the presence of an alkali.

  Examples of organic solvents include methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol, and other alcohols; acetic acid methyl ester , Esters such as ethyl acetate, butyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether; acetone , Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, Ketones such as Seto acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

  The total concentration of the fine particles and the polymer silane coupling agent in the dispersion is preferably in the range of 1 to 30% by weight, more preferably 2 to 25% by weight as the solid content.

  An alkali is added to the dispersion to adsorb the polymer silane coupling agent to the fine particles. By adding an alkali, the surface of the fine particles is activated (an OH group is generated), and the affinity between the polymer silane coupling agent and the fine particles increases and bonds. Alternatively, it is conceivable that the dehydration reaction between the OH group of the polymer silane coupling agent and the OH group of the fine particles is promoted to promote bonding.

  As the alkali, basic nitrogen compounds such as ammonia and amines are used in addition to sodium hydroxide and potassium hydroxide. Among these, a basic nitrogen compound is preferable because the adsorption and bonding of the polymer silane coupling agent to the fine particles are promoted and the amount of the unadsorbed polymer silane coupling agent is small.

  The amount of alkali used varies depending on the type of metal oxide particles, the average particle diameter, etc., but is in the range of 0.001 to 0.2 parts by mass of fine particles, and further 0.005 to 0.1 parts by mass. Is preferred.

  Subsequently, the polymer silane coupling agent-coated fine particles can be obtained by separating and drying the fine particles adsorbed with the polymer silane coupling agent. The average particle diameter of the resulting polymer silane coupling agent-coated fine particles is preferably in the range of 5 nm to 5 μm, more preferably 10 nm to 3 μm, from the viewpoint of optical properties when used for a hard coat film.

  The content of the polymer silane coupling agent-coated fine particles in the second functional layer is 0.5 to 80 parts by mass, further 1 to 60 parts by mass as the solid content, and the film strength of the second functional layer It is preferable from the viewpoint of ensuring.

(Fine particles)
The second functional layer may contain uncoated fine particles in addition to the above-described polymer silane coupling agent-coated fine particles to form surface irregularities, and may exhibit antiblocking properties. Examples of the fine particles include organic fine particles such as polymethyl methacrylate, polystyrene and nylon 12, and inorganic fine particles such as silica. The average particle diameter of the fine particles is preferably in the range of 5 nm to 5 μm, and more preferably in the range of 10 nm to 3 μm, from the viewpoint of optical characteristics when used for a hard coat film. The content of the fine particles in the second functional layer is preferably 0.5 to 80 parts by mass, more preferably 1 to 60 parts by mass as the solid content, from the viewpoint of securing the film strength of the second functional layer. . The fine particles and the polymer silane coupling agent-coated fine particles described above may be contained in the first functional layer. These fine particles may be used in combination.

(Phase separation)
A 2nd functional layer may form surface unevenness | corrugation by a phase-separation structure, and may express antiblocking property. For example, the non-reactive acrylic resin and the ultraviolet curable acrylate resin having the above-mentioned ethylenically unsaturated double bond are in the weight ratio of the former / the latter = 1/99 to 90/10, preferably 3/97. ˜70 / 30, more preferably 5/95 to 50/50. The two types of acrylic resins are incompatible with each other and have phase separation properties, and are incompatible with each other near the processing temperature. By adopting such a combination, surface irregularities can be formed by the phase separation action.

(Embossing)
By using a metal mold having irregularities on the surface and performing UV embossing on the second functional layer, it is possible to form surface irregularities on the second functional layer and to exhibit antiblocking properties. In UV embossing, a resin layer is formed on the surface of the base film and cured while pressing the resin layer against the uneven surface of the mold, thereby transferring the uneven surface of the mold to the resin layer and forming surface unevenness. Is done. Specifically, an ultraviolet curable resin is applied on a base film, and the ultraviolet curable resin is irradiated with ultraviolet rays from the base film side in a state where the applied ultraviolet curable resin is in close contact with a metal mold. Then, the hard coat film on which the cured resin layer is formed is peeled off from the metal mold to form surface irregularities.

  Next, a compound that may be added to both the first functional layer and the second functional layer and a method for forming the functional layer will be described. In addition, when describing as a functional layer, it shall include both a 1st functional layer and a 2nd functional layer.

(Conductive agent)
The functional layer may contain a conductive agent in order to impart antistatic properties. Preferred conductive agents include metal oxide particles or π-conjugated conductive polymers. An ionic liquid is also preferably used as the conductive compound.

(Additive)
The functional layer may contain a fluorine-siloxane graft compound, a fluorine-based compound, or a compound having an HLB value of 3 to 18 in view of applicability. The hydrophilicity can be easily controlled by adjusting the types and amounts of these additives.

The HLB value is Hydrophile-Lipophile-Balance, hydrophilic-lipophilic-balance, and is a value indicating the hydrophilicity or lipophilicity of a compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.
HLB = 7 + 11.7Log (Mw / Mo)
In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like. Specific examples of the compound having an HLB value of 3 to 18 are listed below, but are not limited thereto. Figures in parentheses indicate HLB values.

  Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 7 9 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfi Knoll 420 (4), Surfynol 440 (8), Surfynol 46 (13), Surfinol 485 (17), Surfinol SE (6), manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-4272 (7), X-22-6266 (8), KF-351 (12), KF-352 (7), KF-353 (10), KF-354L (16), KF-355A (12), KF-615A (10), KF-945 (4), KF-618 (11), KF -6011 (12), KF-6015 (4), KF-6004 (5).

  The fluorine-siloxane graft compound refers to a compound of a copolymer obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone on at least a fluorine-based resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Or as a commercial item, Fuji Chemical Industries Ltd. ZX-022H, ZX-007C, ZX-049, ZX-047-D etc. can be mentioned. Further, examples of the fluorine-based compound include Megafac series (F-477, F-487, F-569, etc.) manufactured by DIC Corporation, OPTOOL DSX, OPTOOL DAC, etc. manufactured by Daikin Industries, Ltd. These components are preferably added in the range of 0.005 parts by mass or more and 5 parts by mass or less with respect to the solid component in the functional layer composition.

(UV absorber)
The functional layer may further contain an ultraviolet absorber described in the cellulose ester film described later. As a structure of the film in the case of containing an ultraviolet absorber, when it is constituted by two or more layers, it is preferable that the functional layer in contact with the cellulose ester film contains an ultraviolet absorber.

  The content of the ultraviolet absorber is preferably such that the mass ratio is ultraviolet absorber: functional layer constituting resin = 0.01: 100 to 10: 100. When two or more functional layers are provided, the thickness of the functional layer in contact with the cellulose ester film is preferably in the range of 0.05 to 2 μm. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layering is to form a functional layer by applying two or more functional layers on a substrate by wet on wet without passing through a drying step. In order to laminate the second functional layer on the first functional layer without a drying step, the layers are stacked on top of each other by using an extrusion coater or by using a slot die having a plurality of slits. Simultaneous layering may be performed.

(solvent)
The functional layer is a component that forms the functional layer described above, diluted with a solvent that swells or partially dissolves the cellulose ester film, and is applied onto the cellulose film as a functional layer composition by the following method. It is preferably formed by drying and curing.

  As the solvent, ketone (methyl ethyl ketone, acetone, etc.) and / or acetate ester (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohol (ethanol, methanol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone, etc. are preferable. The application amount of the functional layer is suitably in the range of 0.1 to 40 μm, preferably in the range of 0.5 to 30 μm, as the wet film thickness. The dry film thickness is in the range of 0.01 to 20 μm, preferably in the range of 0.5 to 10 μm. More preferably, it is the range of 0.5-5 micrometers.

  As a method for applying the functional layer, known methods such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method can be used.

(Functional layer forming method)
After applying the functional layer composition, the functional layer composition may be dried and cured (heat or active ray irradiation (also referred to as UV curing)), and if necessary, heat treatment may be performed after curing. The heat treatment temperature after curing is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, particularly preferably 120 ° C. or higher. By performing the heat treatment after curing at such a high temperature, a functional layer having excellent film strength can be obtained.

  Drying is preferably performed at a temperature in the decreasing rate drying section of 30 ° C. or higher. More preferably, the temperature of the decreasing rate drying section is 50 ° C. or higher.

  In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the decreasing rate drying section.

  As a light source used for the UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

The irradiation conditions vary depending on individual lamps, irradiation of actinic rays is generally within the range of 50~1000mJ / cm ^2, preferably in the range of 50 to 300 mJ / cm ^2. Further, in UV curing, oxygen removal (for example, replacement with an inert gas such as nitrogen purge) can be performed to prevent reaction inhibition by oxygen. The cured state of the surface can be controlled by adjusting the removal amount of the oxygen concentration. Thereby, it is easy to control the Δθ within the range.

  The curing is preferably performed while applying a tension in the film conveyance direction, and more preferably while applying a tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the conveying direction on the back roller, or tension may be applied in the width direction or biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

  The functional layer may be surface-modified, or the functional layer may be formed by coating, drying, or the like after the surface modification of the film substrate described below. Examples of the surface modification method include plasma irradiation treatment, corona irradiation treatment, solvent treatment and the like. These surface modification methods may be performed singly or in combination.

  Moreover, it is preferable that the haze of the hard coat film of this embodiment exists in the range of 0.1 to 10% from the visibility at the time of using for an image display apparatus. Haze can be measured according to JIS-K7105 and JIS K7136.

(hardness)
The hard coat film of the present embodiment is a film having a pencil hardness, which is an index of hardness, of 6B or more, and more preferably 4B or more. For the pencil hardness, the prepared hard coat film is conditioned at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more, and then the functional layer is formed using a test pencil specified by JIS S 6006 under a load of 500 g. It is the value measured according to the pencil hardness evaluation method prescribed | regulated by JISK5400.

(Breathable)
The hard coat film of the present embodiment preferably has a moisture permeability of 60 ° C., a relative humidity of 95%, and a moisture permeability of 24 g / hour is 2000 g / m ² or less, more preferably 1000 g / m ² or less. The value of moisture permeability is the weight (g) of water vapor passing through a sample of area 1 m ² in 24 hours in an atmosphere of temperature 60 ° C. and relative humidity 95% according to JIS Z 0208 moisture permeability test (cup method). Is a measured value.

[Film base]
Next, the film substrate according to the present embodiment will be described. As a film base material, it is preferable that manufacture is easy, adhesiveness with a functional layer is favorable, it is optically isotropic, and it is transparent. The film substrate is not particularly limited as long as it has the above-mentioned properties. For example, cellulose ester films such as cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose acetate butyrate film, etc. , Polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl Alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, cycloo Fin polymer film (Arton (manufactured by JSR), ZEONEX, ZEONOR (manufactured by ZEON CORPORATION)), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, A polymethyl methacrylate film, an acrylic film, a polylactic acid film, a glass plate, etc. can be mentioned. Among these, a cellulose ester film, a polycarbonate film, and a cycloolefin polymer film are preferable.

  Examples of the cellulose ester film (hereinafter also referred to as cellulose acetate film) include a triacetyl cellulose film, a cellulose acetate propionate film, a cellulose diacetate film, and a cellulose acetate butyrate film. The cellulose ester film may be used in combination with polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, polyethylene resins, polypropylene resins, norbornene resins, fluororesins, and cycloolefin polymers. Examples of the commercially available cellulose ester film include Konica Minoltak KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC2UA, KC4UE and KC4UZ (manufactured by Konica Minolta, Inc.). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured according to JIS K7142-2008.

(Cellulose ester resin)
The cellulose ester resin (hereinafter also referred to as cellulose ester or cellulose resin) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propio Nate, mixed fatty acid ester such as cellulose acetate butyrate can be used.

  Among the above descriptions, the lower fatty acid esters of cellulose that are particularly preferably used are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

  As the cellulose diacetate, those having an average degree of acetylation (bound acetic acid amount) of 51.0% to 56.0% are preferably used. Examples of commercially available products include L20, L30, L40, and L50 manufactured by Daicel Corporation, and Ca398-3, Ca398-6, Ca398-10, Ca398-30, and Ca394-60S manufactured by Eastman Chemical Japan Co., Ltd. .

  The cellulose triacetate preferably has an average degree of acetylation (bound acetic acid amount) of 54.0 to 62.5%, and more preferably cellulose triacetate having an average degree of acetylation of 58.0 to 62.5%. is there.

  Cellulose triacetate has a number average molecular weight (Mn) of 125,000 or more and less than 155000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, and Mw / Mn of 1.9 to 2.1. Cellulose triacetate B having a substitution degree of 2.75 to 2.90, a number average molecular weight (Mn) of 155,000 or more and less than 180,000, Mw of 290000 or more and less than 360,000, and Mw / Mn of 1.8 to 2.0 It is preferable to contain.

Cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent, and when the substitution degree of acetyl group is X and the substitution degree of propionyl group or butyryl group is Y, the following formula (I ) And (II) are preferably satisfied at the same time.
Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5

 Among them, it is preferable that 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9.

The method for measuring the substitution degree of the acyl group can be measured according to ASTM-D817-96. The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.
Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 100000 to 500 samples were used. The 13 samples are preferably used at approximately equal intervals.

(Thermoplastic acrylic resin)
The cellulose ester film may be used in combination with a thermoplastic acrylic resin. When using together, it is preferable that the containing mass ratio of a thermoplastic acrylic resin and a cellulose-ester resin is thermoplastic acrylic resin: cellulose-ester resin = 95: 5-50: 50.

  Acrylic resin also includes methacrylic resin. Although it does not restrict | limit especially as an acrylic resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable. Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride and the like can be mentioned. These may be used alone or in combination of two or more. Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer, and methyl acrylate and n -Butyl acrylate is particularly preferably used. Moreover, it is preferable that a weight average molecular weight (Mw) is 80000-500000, More preferably, it exists in the range of 110000-500000.

  The weight average molecular weight of the acrylic resin can be measured by gel permeation chromatography. Commercially available acrylic resins include, for example, Delpet 60N, 80N (Asahi Kasei Chemicals Corporation), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) )) And the like. Two or more acrylic resins can be used in combination.

(Λ / 4 film)
A λ / 4 film may be used as the film substrate. By using a λ / 4 film as a film substrate, not only the objective effect of this embodiment can be obtained well, but also when the hard coat film of this embodiment is incorporated in an image display device, it is also excellent in crosstalk. preferable.

  A λ / 4 film refers to a film having an in-plane retardation of the film of about ¼ for a predetermined wavelength of light (usually in the visible light region). The λ / 4 film is preferably a broadband λ / 4 film having a phase difference of approximately ¼ of the wavelength in the visible light wavelength range in order to obtain almost perfect circularly polarized light in the visible light wavelength range. .

The λ / 4 film has an in-plane retardation value Ro (550) measured at a wavelength of 550 nm, preferably in the range of 60 nm to 220 nm, more preferably in the range of 80 nm to 200 nm, and more preferably in the range of 90 nm to 190 nm. More preferably, it is the range. The in-plane retardation value Ro is represented by the following formula.
Ro = (nx−ny) × d
However, in the formula, nx and ny are the maximum refractive index in the plane of the film (also referred to as the refractive index in the slow axis direction) out of the refractive index at 23 ° C. and 55% RH and the wavelength of 550 nm, and in the plane of the film. It is the refractive index in the direction perpendicular to the slow axis, and d is the thickness (nm) of the film.

  Ro can be calculated by measuring the birefringence at each wavelength in an environment of 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments).

  Further, in order to function effectively as a λ / 4 film, it is preferable to satisfy the relationship of Ro (590) −Ro (450) ≧ 2 nm at the same time, and Ro (590) −Ro (450) ≧ 5 nm. It is more preferable that Ro (590) -Ro (450) ≧ 10 nm. Note that Ro (A) refers to the in-plane retardation value Ro measured at the wavelength Anm.

  A circularly polarizing plate is obtained by laminating so that the angle between the slow axis of the λ / 4 film and the transmission axis of the polarizer described later is substantially 45 °. Substantially 45 ° means in the range of 30 ° to 60 °, more preferably in the range of 40 ° to 50 °. The angle between the slow axis in the plane of the λ / 4 film and the transmission axis of the polarizer is preferably 41 to 49 °, more preferably 42 to 48 °, and 43 to 47 °. Is still more preferable, and it is still more preferable that it is 44-46 degrees.

  The λ / 4 film is not particularly limited as long as it is an optically transparent resin. For example, an acrylic resin, a polycarbonate resin, a cycloolefin resin, a polyester resin, a polylactic acid resin, a polyvinyl alcohol resin, The cellulose-based resin described above can be used. Among these, from the viewpoint of chemical resistance, the λ / 4 film is preferably a cellulose resin or a polycarbonate resin. From the viewpoint of heat resistance, the λ / 4 film is preferably a cellulose resin.

  The retardation of the λ / 4 film may be adjusted by adding the following retardation adjuster to the resin film described above.

(Retardation adjuster)
As the retardation adjusting agent, an aromatic compound having two or more aromatic rings as described in the specification of European Patent 911,656A2 can be used.

  Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. Particularly preferred is an aromatic heterocycle, and the aromatic heterocycle is generally an unsaturated heterocycle. Of these, a 1,3,5-triazine ring is particularly preferred.

(Polycarbonate resin)
For the film base (or λ / 4 film), a polycarbonate-based resin can also be used. Various polycarbonate resins can be used without particular limitation, and aromatic polycarbonate resins are preferred from the viewpoint of chemical properties and physical properties, and bisphenol A polycarbonate resins are particularly preferred. Among these, those using a bisphenol A derivative in which a benzene ring, a cyclohexane ring, an aliphatic hydrocarbon group and the like are introduced into bisphenol A are more preferable.

  Furthermore, a polycarbonate resin having a structure in which the anisotropy in the unit molecule is reduced, obtained by using a derivative in which the functional group is introduced asymmetrically with respect to the central carbon of bisphenol A, is particularly preferable. As such a polycarbonate resin, for example, two methyl groups in the center carbon of bisphenol A are replaced by benzene rings, and one hydrogen of each benzene ring of bisphenol A is centered by a methyl group or a phenyl group. A polycarbonate resin obtained by using an asymmetrically substituted carbon is particularly preferable.

  Specifically, 4,4′-dihydroxydiphenylalkane or a halogen-substituted product thereof is obtained by a phosgene method or a transesterification method. For example, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenylethane 4,4'-dihydroxydiphenylbutane and the like. In addition, for example, JP 2006-215465 A, JP 2006-91836 A, JP 2005-121813 A, JP 2003-167121 A, JP 2009-126128 A, JP Examples thereof include polycarbonate resins described in 2012-31369, JP 2012-67300 A, International Publication No. 00/26705, and the like.

  The polycarbonate resin may be used by mixing with a transparent resin such as a polystyrene resin, a methyl methacrylate resin, and a cellulose acetate resin. Moreover, you may laminate | stack the resin layer containing a polycarbonate-type resin on the at least one surface of the resin film formed using the cellulose acetate type resin.

  The polycarbonate resin preferably has a glass transition point (Tg) of 110 ° C. or higher and a water absorption rate (measured under conditions of 23 ° C. water and 24 hours) of 0.3% or less. Moreover, Tg is 120 degreeC or more, and a water absorption rate is 0.2% or less more preferable. The polycarbonate resin film can be formed by a known method, and among them, the solution casting method and the melt casting method are preferable.

(Alicyclic olefin polymer resin)
As the film substrate (or λ / 4 film), an alicyclic olefin polymer resin can also be used. Examples of alicyclic olefin polymer resins include cyclic olefin random multi-component copolymers described in JP-A No. 05-310845, hydrogenated polymers described in JP-A No. 05-97978, and JP-A No. 11 The thermoplastic dicyclopentadiene ring-opening polymer and hydrogenated product thereof described in JP-A No. 124244 can be employed.

  The alicyclic olefin polymer resin is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and formability of the long film are highly balanced and suitable.

  The proportion of the repeating unit containing the alicyclic structure in the alicyclic olefin polymer may be appropriately selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it. When the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is within this range, transparency and heat resistance of an optical material such as a retardation film obtained from a long obliquely stretched film described later are improved. Therefore, it is preferable.

  Examples of olefin polymer resins having an alicyclic structure include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. . Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. And an addition copolymer of a monomer having a norbornene structure and an addition copolymer of another monomer or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability and lightness. Can be used. As a method for forming a long film using the norbornene-based resin as described above, a solution casting method or a melt extrusion method is preferred. Examples of the melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

  As an extrusion molding method using a T-die, a method for keeping a molten thermoplastic resin in a stable state when in close contact with a cooling drum as described in JP-A-2004-233604 can be employed. Thereby, a long film with small variation in optical properties such as retardation and orientation angle can be produced. Specifically, 1) When producing a long film by the melt extrusion method, a sheet-like thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less; 2) melting When producing a long film by extrusion, the enclosure member covers from the die opening to the first cooling drum that is in close contact, and the distance from the enclosure member to the die opening or the first contact cooling drum is 100 mm or less. Method: 3) Method of heating the temperature of the atmosphere within 10 mm to a specific temperature from the sheet-like thermoplastic resin extruded from the die opening when producing a long film by the melt extrusion method; A sheet-like thermoplastic resin extruded from a die so as to satisfy the above condition is brought into close contact with a cooling drum under a pressure of 50 kPa or less; A method in which a wind having a speed difference of 0.2 m / s or less from the take-up speed of the cooling drum that is first brought into close contact with the sheet-like thermoplastic resin extruded from the die opening is produced. .

  The long film may be a single layer or a laminated film of two or more layers. The laminated film can be obtained by a known method such as a coextrusion molding method, a co-casting molding method, a film lamination method, or a coating method. Of these, the coextrusion molding method and the co-casting molding method are preferable.

(Fine particles)
In order to improve the handling property, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate Further, it is preferable to contain inorganic fine particles such as magnesium silicate and calcium phosphate and a matting agent such as a crosslinked polymer. The acrylic particles are not particularly limited, but are preferably multi-layered acrylic granular composites. Among these, silicon dioxide is preferable in that the haze of the cellulose ester film can be reduced. The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably in the range of 5 to 16 nm, and particularly preferably in the range of 5 to 12 nm.

(Polymer containing repeating units derived from the monomer represented by formula (P))
The film substrate preferably contains a polymer containing a repeating unit derived from a monomer represented by the following general formula (P).

In the formula, R ¹ represents a hydrogen atom or an aliphatic group having 1 to 4 carbon atoms. R ¹ is not particularly limited, but is preferably a hydrogen atom, a methyl group, or an ethyl group.

R ² represents a substituent. As the substituent, an aliphatic group or an aromatic group is preferable. R ² is not particularly limited, but the aliphatic group is preferably an alkyl group, an alkenyl group, an alkynyl group or a cycloalkyl group, more preferably an alkyl group having 1 to 6 carbon atoms, a methyl group, an ethyl group or a propyl group. A butyl group is more preferable, and a methyl group and a t-butyl group are particularly preferable. As the aromatic group, a phenyl group, a naphthyl group, and a biphenyl group are preferable, and a phenyl group is particularly preferable.

n represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 to 1. In addition, when n is 0, the substituent R ² does not exist, but in the chemical formula, this means that a hydrogen atom may be present here.

  (A) represents an atomic group necessary for forming a 5- or 6-membered ring, and is preferably a 5- or 6-membered aromatic ring. The aromatic ring in this specification is a concept including an aromatic ring not containing a heteroatom and a saturated / unsaturated heterocycle having a heteroatom.

  From the effect of suppressing moisture permeability and moisture content of the film, the polymer represented by the general formula (P) preferably has a mass average molecular weight of 200 to 10,000, more preferably 300 to 8,000. 400 to 4,000 is particularly preferable. If it is less than or equal to the upper limit, an improvement in compatibility with cellulose acylate can be expected.

  Unless otherwise specified, the molecular weight and the degree of dispersion are values measured using a GPC (gel filtration chromatography) method, and the molecular weight can be measured by a polystyrene-reduced mass average molecular weight.

  The gel packed in the column used for the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel made of a styrene-divinylbenzene copolymer. It is preferable to use 2 to 6 columns connected together. Examples of the solvent used include ether solvents such as tetrahydrofuran and amide solvents such as N-methylpyrrolidinone. The measurement is preferably performed at a solvent flow rate in the range of 0.1 to 2 mL / min, and most preferably in the range of 0.5 to 1.5 mL / min. By performing the measurement within this range, the apparatus is not loaded and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, most preferably 20 to 40 ° C. The column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound to be measured.

  Although the addition amount of the polymer represented by general formula (P) is not specifically limited, It is preferable that it is 0.1-100 mass parts with respect to 100 mass parts of resin which forms a film base material, 0.5- More preferably, it is 50 mass parts, and it is especially preferable that it is 1.0-30 mass parts.

  Although the specific example of the polymer which has a repeating unit derived from the monomer represented with general formula (P) below is shown, a polymer is not necessarily limited to these. In addition, the following structural formula has shown the chemical structure of the repeating unit of the main component, and its structural ratio, and it is as above-mentioned that the other component may be contained.

  The polymer in the present specification includes not only a polymer that is a general polymer compound in which a large number of monomers are polymerized, but also an oligomer that is a compound having a molecular weight of about several hundreds in which several monomers are polymerized. means. Unless otherwise specified, a polymer, copolymer or copolymer is also included.

(Organic acid)
The film substrate may contain an organic acid. The molecular weight of the organic acid is preferably 200 to 1000, more preferably 250 to 800, and particularly preferably 280 to 500. The organic acid preferably includes an aromatic ring structure, preferably includes an aryl group having 6 to 12 carbon atoms, and particularly preferably includes a phenyl group. The aromatic ring structure of the organic acid may form a condensed ring with other rings. The aromatic ring structure of the organic acid may have a substituent, but is preferably a halogen atom or an alkyl group, more preferably a halogen atom or an alkyl group having 1 to 6 carbon atoms, and a chlorine atom. Or it is especially preferable that it is a methyl group. The organic acid is preferably represented by the following general formula (Q).

In the general formula (Q), R ²⁶ represents an aryl group, and R ²⁷ and R ²⁸ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ²⁶ and R ²⁷ may each have a substituent. R ²⁶ is preferably an aryl group having 6 to 18 carbon atoms, more preferably an aryl group having 6 to 12 carbon atoms, and particularly preferably a phenyl group. R ²⁷ and R ²⁸ are each independently preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (including a cycloalkyl group) or an aryl group having 6 to 12 carbon atoms, It is more preferably an alkyl group of 6 (including a cycloalkyl group) or a phenyl group, and particularly preferably a hydrogen atom, a methyl group, an ethyl group, a cyclohexane group or a phenyl group.

  Hereinafter, although the specific example of the organic acid represented by general formula (Q) is illustrated, an organic acid is not necessarily limited to these.

  The content of the organic acid is preferably 1 to 20% by mass with respect to the main component resin constituting the film substrate.

(Compound represented by formula (S))
The film substrate may contain a compound represented by the following general formula (S).

In the general formula (S), R ¹ represents a hydrogen atom or a substituent, and R ² represents a substituent represented by the following general formula (a). n1 represents an integer of 0 to 4. When n1 is 2 or more, the plurality of R1s may be the same as or different from each other. n2 represents an integer of 1 to 5. When n2 is 2 or more, the plurality of R2s may be the same as or different from each other.

In general formula (a), A represents a substituted or unsubstituted aromatic ring. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituent represented by the following general formula (b). R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms. X represents a substituted or unsubstituted aromatic ring. n3 represents an integer of 0 to 10. When n3 is 2 or more, the plurality of R ⁵ and X may be the same as or different from each other.

In general formula (b), X represents a substituted or unsubstituted aromatic ring. R ⁶ , R ⁷ , R ⁸ , and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. n5 represents an integer of 1 to 11. When n5 is 2 or more, the plurality of R ⁶ , R ⁷ , R ⁸ and X may be the same as or different from each other.

  Hereinafter, although the specific example of a compound represented by general formula (S) is shown, a compound is not necessarily limited to these.

  The weight average molecular weight of the compound represented by the general formula (S) is preferably from 200 to 1,200, more preferably from 250 to 1,000, and particularly preferably from 300 to 800.

  Although the addition amount of the compound represented by general formula (S) is not specifically limited, It is preferable from stability with respect to 100 mass parts of film base materials from stability, 0.2-80 It is more preferable that it is a mass part, and it is especially preferable that it is 0.3-60 mass parts.

(Ester compound)
It is preferable that a film base material contains the ester compound or sugar ester represented by the following general formula (X) from the dimensional stability by an environmental change. First, the ester compound represented by the general formula (X) will be described.

Formula (X); B- (GA) n-GB
In the formula, B is a hydroxy group or a carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms. n represents an integer of 1 or more.

  In the general formula (X), as the alkylene glycol component having 2 to 12 carbon atoms, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2 , 2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl- 1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1, -Hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc., and these glycols are one kind or two kinds or more Used as a mixture. In particular, an alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of excellent compatibility with cellulose acetate. Examples of the aryl glycol component having 6 to 12 carbon atoms include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol and the like, and these glycols can be used as one kind or a mixture of two or more kinds.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like. These glycols are one kind or two or more kinds. Can be used as a mixture. Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and the like. Used as a mixture of two or more. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid. Although the specific example (compound X-1-compound X-17) of a compound represented by general formula (X) below is shown, it is not limited to this.

  Next, the sugar ester compound will be described. The sugar ester compound is an ester other than cellulose ester, and is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide. Examples of the sugar include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose And kestose. In addition, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included. Among these compounds, compounds having a furanose structure and / or a pyranose structure are particularly preferable. Among these, sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose and the like are preferable, and sucrose is more preferable. As oligosaccharides, maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides, and xylo-oligosaccharides can also be preferably used.

  The monocarboxylic acid used for esterifying the sugar is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. The carboxylic acid to be used may be one kind or a mixture of two or more kinds. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid , Saturated fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid And unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof. Examples of preferred aromatic monocarboxylic acids include benzoic acid, aromatic monocarboxylic acids having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid, cinnamic acid, benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralin An aromatic monocarboxylic acid having two or more benzene rings such as carboxylic acid, or a derivative thereof can be mentioned, and more specifically, xylic acid, hemelic acid, mesitylene acid, planicylic acid, γ-isojurylic acid, Julylic acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-, m, p-anisic acid, creosote acid, o-, m, p-homosalicylic acid, o-pyrocatechuic acid, β-resorcylic acid, vanillic acid, isovanillic acid, veratrum acid o- veratric acid, gallic acid, asarone acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratric acid, o- homoveratric acid, Futaron acid, can be mentioned p- coumaric acid, especially benzoic acid. Among the ester compounds esterified, an acetyl compound into which an acetyl group has been introduced by esterification is preferable. Although the specific example of a sugar ester compound is shown below, it is not limited to these.

  The sugar ester compound is preferably a compound represented by the general formula (Y). Below, the compound shown by general formula (Y) is demonstrated.

式中、Ｒ_１〜Ｒ_８は、水素原子、置換若しくは無置換の炭素数２〜２２のアルキルカルボニル基、或いは、置換又は無置換の炭素数２〜２２のアリールカルボニル基を表す。Ｒ_１〜Ｒ_８は、同じであっても、異なっていてもよい。

In the formula, R _{1 to} R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms. R _{1 to} R ₈ may be the same or different.

Although the compound shown by general formula (Y) below is shown to more concrete (compound Y-1-compound Y-23), a compound is not limited to these. In the following table, when the average substitution degree is less than 8.0, any one of R _{1 to} R ₈ represents a hydrogen atom.

  The substitution degree distribution can be adjusted to the desired substitution degree by adjusting the esterification reaction time or mixing compounds having different substitution degrees.

  The ester compound or sugar ester compound represented by the general formula (X) is preferably contained in the cellulose acetate film in an amount of 1 to 30% by mass, more preferably 5 to 25% by mass, and more preferably 5 to 20% by mass. It is particularly preferred that

(Plasticizer)
The film substrate may contain a plasticizer as necessary. The plasticizer is not particularly limited, but is a polyvalent carboxylic ester plasticizer, glycolate plasticizer, phthalate ester plasticizer, phosphate ester plasticizer, and polyhydric alcohol ester plasticizer, acrylic. A plasticizer etc. are mentioned. In these, an acrylic plasticizer is preferable from the viewpoint of easily controlling the cellulose ester film to the retardation value described later.

  The polyhydric alcohol ester plasticizer is a plasticizer comprising an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. Preferably it is a 2-20 valent aliphatic polyhydric alcohol ester. Specific examples of the polyhydric alcohol ester plasticizer are shown below, but are not limited thereto.

  The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.

  Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

  The polyvalent carboxylic acid ester plasticizer is a compound composed of an ester of a divalent or higher valent, preferably a divalent to -20 valent polyvalent carboxylic acid and an alcohol. Specific examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, tartaric acid Examples include, but are not limited to, diacetyldibutyl, tributyl trimellitic acid, tetrabutyl pyromellitic acid, and the like.

  The acrylic plasticizer is preferably an acrylic polymer, and the acrylic polymer is preferably a homopolymer or copolymer of acrylic acid or alkyl methacrylate. Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate ( n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic Acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid 2-ethoxyethyl), etc., or the acrylic acid ester may include those obtained by changing the methacrylic acid ester. The acrylic polymer is a homopolymer or copolymer of the above-mentioned monomer, but it is preferable that the acrylic acid methyl ester monomer unit has 30% by mass or more, and the methacrylic acid methyl ester monomer unit has 40% by mass or more. Is preferred. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

  In addition, when making the film base material contain the plasticizer mentioned above, it is preferable to contain 1-50 mass% of the usage-amount with respect to a cellulose acetate, It is more preferable to make 5-35 mass% contain, It is particularly preferable to contain 25% by mass.

(UV absorber)
The film substrate may contain an ultraviolet absorber. Since the ultraviolet absorber absorbs ultraviolet rays of 400 nm or less, durability can be improved. In particular, the ultraviolet absorber preferably has a transmittance of 10% or less at a wavelength of 370 nm, more preferably 5% or less, and still more preferably 2% or less. Specific examples of the ultraviolet absorber are not particularly limited. For example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex salts, inorganic powders. Examples include the body.

  More specifically, for example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6 -(Linear and side chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc. can be used. Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, and TINUVIN 328 manufactured by BASF Japan Ltd. can be preferably used.

  Preferred ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferred are benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.

  In addition, a discotic compound such as a compound having a 1,3,5 triazine ring is also preferably used as the ultraviolet absorber. As the UV absorber, a polymer UV absorber can be preferably used, and a polymer type UV absorber is particularly preferably used.

  As a benzotriazole ultraviolet absorber, TINUVIN 109 (octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole-2-) manufactured by BASF Japan Ltd., which is a commercial product, is available. Yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate), TINUVIN 928 (2 -(2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol) and the like can be used. As the triazine-based ultraviolet absorber, TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -manufactured by BASF Japan Ltd., which is a commercial product, is available. Reaction product of 5-hydroxyphenyl and oxirane), TINUVIN 460 (2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3-5 Triazine), TINUVIN 405 (2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester Reaction products) and the like.

  The ultraviolet absorber is added by dissolving the ultraviolet absorber in an alcohol, such as methanol, ethanol, butanol or the like, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, and then becomes a film substrate. It may be added to the resin solution (dope) or directly during the dope composition. For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose acetate to disperse and then added to the dope.

  0.5-10 mass% is preferable with respect to a cellulose acetate film, and, as for the usage-amount of a ultraviolet absorber, 0.6-4 mass% is still more preferable.

(Antioxidant)
The film substrate may further contain an antioxidant (deterioration inhibitor). The antioxidant has a role of delaying or preventing the cellulose acetate film from being decomposed by a residual solvent amount of halogen in the cellulose acetate film, phosphoric acid of a phosphoric acid plasticizer, or the like. As the antioxidant, hindered phenol compounds are preferably used. For example, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl). -4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3 5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- 3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3 5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate Etc. The addition amount of these compounds is preferably 1 ppm to 10000 ppm, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the cellulose acetate film.

(Disadvantage)
The film substrate preferably has a defect of 5 μm or more in diameter of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

  The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape such as transfer of a roller scratch or an abrasion, the size can be confirmed by observing the defect with the reflected light of a differential interference microscope.

  When the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later step, the film may break from the defect and productivity may decrease. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

  Moreover, even when it cannot be visually confirmed, when a functional layer is formed, a coating film cannot be formed uniformly, resulting in a defect (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film. Further, the film substrate preferably has a breaking elongation of at least one direction of 10% or more, more preferably 20% or more, in the measurement based on JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

(optical properties)
The film substrate preferably has a total light transmittance of 90% or more, more preferably 92% or more. Moreover, as a realistic upper limit, it is about 99%. The haze value is preferably 2% or less, more preferably 1.5% or less. The total light transmittance and haze value can be measured according to JIS K7361 and JIS K7136.

  The in-plane retardation value Ro of the film substrate is preferably in the range of 0 to 5 nm and the retardation value Rth in the thickness direction is in the range of −10 to 10 nm. Further, Rth is preferably in the range of -5 to 5 nm. Or it is preferable that retardation Ro is the range of 30-200 nm, and it is still more preferable that it is the range of 30-90 nm. The retardation value Rth in the thickness direction is preferably in the range of 70 to 300 nm.

The in-plane retardation value Ro is defined by the following formula (I), and the retardation value Rth in the thickness direction is defined by the following formula (II).
Formula (I) Ro = (nx−ny) × d
Formula (II) Rth = {(nx + ny) / 2−nz} × d
In the formula, nx is the refractive index in the slow axis direction in the cellulose ester film plane, ny is the refractive index in the direction perpendicular to the slow axis in the film plane, nz is the refractive index in the thickness direction of the cellulose ester film, d Represents the thickness (nm) of the cellulose ester film. The retardation can be obtained at a wavelength of 590 nm under an environment of 23 ° C. and 55% RH (relative humidity) using, for example, KOBRA-21ADH (manufactured by Oji Scientific Instruments).

[Film formation of cellulose ester film]
Next, the example of the film forming method of the cellulose-ester film as a film base material is demonstrated. The film forming method is not limited to this. As a method for producing a cellulose ester film, production methods such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, a hot press method and the like can be used.

(Organic solvent)
The organic solvent useful for forming a resin solution (dope composition) when a cellulose ester film is produced by a solution casting method is limited as long as it dissolves a cellulose ester resin and other additives at the same time. Can be used. For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, etc. Can, methylene chloride, methyl acetate, ethyl acetate, may be used preferably acetone. The solvent is preferably a dope composition in which a total of 15 to 45 mass% of a cellulose ester resin and other additives are dissolved.

(Solution casting film forming method)
In the solution casting film forming method, a step of preparing a dope by dissolving a resin and an additive in a solvent, a step of casting the dope on a belt-shaped or drum-shaped metal support, and drying the cast dope as a web A step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished cellulose ester film.

  As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used.

  The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

  A preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

In order for the cellulose ester film to obtain good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 60%. It is 130 mass%, Most preferably, it is 20-30 mass% or 70-120 mass%. The amount of residual solvent is defined by the following formula.
Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected at any time during or after the production of the web or film, and N is the mass after heating a mass of M at 115 ° C. for 1 hour.

  Further, in the drying step of the cellulose ester film, the web is peeled off from the metal support and dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably. Is 0 to 0.01% by mass or less.

  In the film drying step, generally, a roller drying method (a method in which webs are alternately passed through a plurality of upper and lower rollers) and a method of drying while conveying the web by a tenter method are employed.

  In the stretching step, the film can be sequentially or simultaneously stretched in the longitudinal direction (MD direction) and the width direction (TD direction) of the film. The draw ratios in the biaxial directions perpendicular to each other are preferably 1.0 to 2.0 times in the MD direction and 1.05 to 2.0 times in the TD direction, respectively. It is preferably performed in a range of 1.0 to 1.5 times and 1.05 to 2.0 times in the TD direction. For example, a method of making a difference in peripheral speed between a plurality of rollers and stretching in the MD direction using the difference in peripheral speed of the roller between them, fixing both ends of the web with clips and pins, and widening the interval between the clips and pins in the traveling direction And a method of stretching in the MD direction, a method of stretching in the lateral direction and stretching in the TD direction, a method of stretching the MD direction and the TD direction simultaneously, and stretching in both directions.

  These width maintenance or width direction stretching in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

  The film transport tension in the film forming process such as a tenter depends on the temperature, but is preferably 120 to 200 N / m, and more preferably 140 to 200 N / m. 140 to 160 N / m is most preferable.

  The temperature during stretching is (Tg-30) to (Tg + 100) ° C., more preferably (Tg-20) to (Tg + 80) ° C., more preferably (Tg-5), where Tg is the glass transition temperature of the cellulose ester film. ~ (Tg + 20) ° C.

  The Tg of the cellulose ester film can be controlled by the material type constituting the film and the ratio of the constituting materials. The Tg when the cellulose ester film is dried is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. Especially preferably, it is 150 degreeC or more. The glass transition temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower. The Tg of the cellulose ester film can be determined by the method described in JIS K7121. The stretching temperature is preferably 150 ° C. or more and the stretching ratio is 1.15 times or more because the surface is appropriately roughened. Roughening the surface of the cellulose ester film is preferable because it improves slipperiness and improves surface processability.

(Melt casting method)
The cellulose ester film may be formed by a melt casting film forming method. In the melt casting film forming method, a composition containing other additives such as a cellulose ester resin and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing the fluid cellulose ester is cast. This is a film forming method.

  In the melt casting film forming method, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

  Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder with a feeder and kneaded using a single-screw or twin-screw extruder, and formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

  A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

  The extruder is preferably processed at a temperature as low as possible so that it can be pelletized so that the shearing force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

  A film is formed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

  Using a single or twin screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matter, and then formed into a film from a T die. The cellulose ester film is formed by niping the film with a cooling roller and an elastic touch roller and solidifying the film on the cooling roller.

  When introducing into the extruder from the supply hopper, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

  The extrusion flow rate is preferably adjusted stably by introducing a gear pump or the like. Moreover, as a filter used for removal of a foreign material, a stainless fiber sintered filter is preferably used. The stainless steel fiber sintered filter compresses the stainless steel fiber body after creating a complex intertwined state, and sinters and integrates the contact points. By changing the density according to the thickness of the fiber and the compression amount, The filtration accuracy can be adjusted.

  Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

  The temperature of the cellulose ester film on the touch roller side when the cellulose ester film is nipped by the cooling roller and the elastic touch roller is preferably not less than Tg (Tg + 110 ° C.) of the film. A known roller can be used as the roller having an elastic surface used for such a purpose.

  The elastic touch roller is also called a pinching rotary member. A commercially available elastic touch roller can also be used.

  When peeling the cellulose ester film from the cooling roller, it is preferable to control the tension to prevent deformation of the film.

  Moreover, it is preferable that the cellulose ester film obtained as described above is stretched by the stretching operation after passing through the step of contacting the cooling roller. As a stretching method, a known roller stretching machine, a tenter or the like can be preferably used. The stretching temperature is preferably carried out in the temperature range of Tg to (Tg + 60) ° C. of the resin that usually constitutes the film.

  Before winding up the film, the end may be slit and trimmed to the product width, and knurled (embossing) may be applied to both ends to prevent sticking and scratching during winding. The knurling can be performed by heating or pressurizing using a metal ring having an uneven pattern on the side surface. Since the cellulose ester film is usually deformed and cannot be used as a product, the clip holding portions at both ends of the film are cut out and reused.

[Method for producing obliquely stretched film]
The aforementioned λ / 4 film can be manufactured by the following oblique stretching. The obliquely stretched film can be produced by producing a stretched film having a slow axis at an angle of more than 0 ° and less than 90 ° with respect to the film extension direction (longitudinal direction). In addition, as a non-stretched film before diagonally stretching, the well-known film mentioned above can be used.

  Here, the angle with respect to the extending direction of the film is an angle in the film plane. Since the slow axis is usually expressed in the stretching direction or a direction perpendicular to the stretching direction, stretching having such a slow axis is performed by stretching at an angle of more than 0 ° and less than 90 ° with respect to the extending direction of the film. A film can be manufactured.

  The angle (orientation angle θ) formed by the extension direction of the film and the slow axis can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °, more preferably 10 ° to 80 °. °, more preferably 40 ° to 50 °.

(Diagonal stretching)
An obliquely stretched film can be produced using an obliquely stretching apparatus (obliquely stretched tenter). As an obliquely stretched tenter, the orientation angle of the film can be set freely by changing the rail pattern in various ways, and furthermore, the orientation axis of the film can be oriented with high precision evenly on the left and right across the width direction of the film. An apparatus capable of controlling the film thickness and retardation with high accuracy can be preferably used. Next, a specific method for producing an obliquely stretched film will be described with reference to the drawings.

  FIG. 6 is a plan view schematically showing a schematic configuration of the obliquely stretched film manufacturing apparatus 51. The manufacturing apparatus 51 includes, in order from the upstream side in the transport direction of the long film, a film feeding unit 52, a transport direction changing unit 53, a guide roll 54, a stretching unit 55, a guide roll 56, and a transport direction changing unit 57. A film cutting device 58 and a film take-up unit 59 are provided. Details of the extending portion 55 will be described later.

  The film feeding unit 52 feeds the above-described long film and supplies it to the stretching unit 55. The film feeding portion 52 may be configured separately from the long film forming apparatus or may be configured integrally. In the case of the former, a long film is wound around a core once after film formation, and a wound body (long film original fabric) is loaded into the film unwinding part 52 so that the film unwinds from the film unwinding part 52. The film is paid out. On the other hand, in the latter case, the film feeding portion 52 is fed to the stretching portion 55 without winding the long film after the long film is formed.

  The conveyance direction changing unit 53 changes the conveyance direction of the long film fed from the film feeding unit 52 to a direction toward the entrance of the stretching unit 55 as an oblique stretching tenter. Such a conveyance direction change part 53 is comprised including the turntable which rotates the turn bar in the surface parallel to a film, and the turn bar which changes a conveyance direction by folding, for example, conveying a film.

  By changing the transport direction of the long film as described above by the transport direction changing unit 53, the width of the entire manufacturing apparatus 51 can be made narrower, and the film feed position and angle are finely controlled. Thus, it is possible to obtain a long obliquely stretched film with small variations in film thickness and optical value. In addition, if the film feeding unit 52 and the conveyance direction changing unit 53 are movable (slidable and turnable), the left and right clips (gripping tools) sandwiching both ends in the width direction of the long film in the stretching unit 55 are arranged. It is possible to effectively prevent the biting into the film.

  In addition, the above-described film feeding unit 52 may be slidable and turnable so that a long film can be fed out at a predetermined angle with respect to the entrance of the stretching unit 55. In this case, it is also possible to adopt a configuration in which the installation of the conveyance direction changing unit 53 is omitted.

  At least one guide roll 54 is provided on the upstream side of the extending portion 55 in order to stabilize the track during running of the long film. The guide roll 54 may be composed of a pair of upper and lower rolls sandwiching the film, or may be composed of a plurality of roll pairs. The guide roll 54 closest to the entrance of the extending portion 55 is a driven roll that guides the travel of the film, and is rotatably supported by bearings (not shown). As the material of the guide roll 54, a known material can be used. In order to prevent the film from being damaged, it is preferable to reduce the weight of the guide roll 54 by applying a ceramic coat on the surface of the guide roll 54 or applying chrome plating to a light metal such as aluminum.

  Further, it is preferable that one of the rolls upstream of the guide roll 54 closest to the entrance of the extending portion 55 is nipped by pressing the rubber roll. By setting it as such a nip roll, it becomes possible to suppress the fluctuation | variation of the drawing tension | tensile_strength in the flow direction of a film.

  A pair of bearing portions at both ends (left and right) of the guide roll 54 closest to the entrance of the extending portion 55 includes a first tension detection device as a film tension detection device for detecting the tension generated in the film in the roll, A second tension detecting device is provided. For example, a load cell can be used as the film tension detection device. As the load cell, a known tensile or compression type can be used. A load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.

  The load cell is installed in the left and right bearing portions of the guide roll 54 closest to the entrance of the extending portion 55, so that the force of the running film on the roll, that is, in the film traveling direction generated in the vicinity of both side edges of the film. The tension is detected independently on the left and right. In addition, a strain gauge may be directly attached to a support that constitutes the bearing portion of the roll, and a load, that is, a film tension may be detected based on the strain generated in the support. The relationship between the generated strain and the film tension is measured in advance and is known.

  When the position and the transport direction of the film supplied from the film feeding unit 52 or the transport direction changing unit 53 to the stretching unit 55 are deviated from the position toward the entrance of the stretching unit 55 and the transport direction, according to this misalignment amount, A difference occurs in the tension in the vicinity of both side edges of the film in the guide roll 54 closest to the entrance of the stretching portion 55. Therefore, by providing the above-described film tension detecting device and detecting the above-described tension difference, the degree of the deviation can be determined. That is, if the transport position and transport direction of the film are appropriate (if it is the position and direction toward the entrance of the stretching section 55), the load acting on the guide roll 54 is roughly uniform at both ends in the axial direction. If not appropriate, there will be a difference in film tension between left and right.

  Therefore, for example, the above-described transport direction changing unit 53 changes the film position and transport direction (angle with respect to the entrance of the stretching unit 55) so that the left and right film tension differences between the guide rolls 54 closest to the entrance of the stretching unit 55 become equal. When properly adjusted, the film can be stably held by the gripping tool at the entrance of the extending portion 55, and the occurrence of obstacles such as detachment of the gripping tool can be reduced. Furthermore, the physical properties in the width direction of the film after oblique stretching by the stretching portion 55 can be stabilized.

  At least one guide roll 56 is provided on the downstream side of the stretching portion 55 in order to stabilize the track during travel of the film that is obliquely stretched by the stretching portion 55.

  The transport direction changing unit 57 changes the transport direction of the stretched film transported from the stretching unit 55 to a direction toward the film winding unit 59.

  Here, in order to cope with fine adjustment of the orientation angle (the direction of the in-plane slow axis of the film) and product variations, the film traveling direction at the entrance of the stretching portion 55 and the film traveling direction at the exit of the stretching portion 55 It is necessary to adjust the angle between the two. In order to adjust the angle, the traveling direction of the formed film is changed by the transport direction changing unit 53 to guide the film to the inlet of the stretching unit 55 and / or the traveling direction of the film from the outlet of the stretching unit 55 Needs to be changed by the transport direction changing unit 57 to return the film to the direction of the film winding unit 59.

  Moreover, it is preferable from the point of productivity and a yield to perform film forming and diagonal stretch continuously. When the film forming process, the oblique stretching process, and the winding process are continuously performed, the traveling direction of the film is changed by the transport direction changing unit 53 and / or the transport direction changing unit 57, and the film is formed by the film forming process and the winding process. That is, as shown in FIG. 6, the traveling direction of the film fed out from the film feeding portion 52 (feeding direction) and the traveling direction of the film immediately before being wound up by the film winding portion 59 ( The width of the entire apparatus with respect to the film traveling direction can be reduced by matching the winding direction.

  In addition, although the advancing direction of a film does not necessarily need to correspond in a film forming process and a winding process, the conveyance direction change part 53 and the film feeding part 52 and the film winding part 59 are set so that it may become a layout which does not interfere. It is preferable to change the traveling direction of the film by the transport direction changing unit 57.

  The transport direction changing units 53 and 57 as described above can be realized by a known method such as using an air flow roll or an air turn bar.

  The film cutting device 58 cuts the film stretched by the stretching section 55 (long oblique stretched film) along a cross section including the width direction, and has a cutting member. The cutting member is composed of, for example, a scissor or a cutter (including a slitter, a strip-shaped blade (Thomson blade)), but is not limited thereto, and in addition, a rotating circular saw, a laser irradiation device, etc. It is also possible to configure.

  The film take-up unit 59 takes up the film conveyed from the stretching unit 55 via the conveyance direction changing unit 57, and includes, for example, a winder device, an accumulator device, and a drive device. It is preferable that the film winding unit 59 has a structure that can be slid in the lateral direction in order to adjust the film winding position.

  The film take-up portion 59 can finely control the film take-up position and angle so that the film can be taken at a predetermined angle with respect to the outlet of the stretching portion 55. Thereby, it becomes possible to obtain a long obliquely stretched film with small variations in film thickness and optical value. In addition, it is possible to effectively prevent wrinkling of the film and to improve the winding property of the film, so that the film can be wound up in a long length.

  The film take-up unit 59 constitutes a take-up unit that takes up the film stretched and conveyed by the stretch unit 55 with a constant tension. In addition, you may make it provide the take-up roll for taking up a film with fixed tension | tensile_strength between the extending | stretching part 55 and the film winding-up part 59. FIG. Further, the guide roll 56 described above may have a function as the take-up roll.

  In the present embodiment, the take-up tension T (N / m) of the film after stretching is preferably adjusted between 100 N / m <T <300 N / m, preferably 150 N / m <T <250 N / m. When the take-up tension is 100 N / m or less, sagging and wrinkles of the film are likely to occur, and the retardation and orientation angle profile in the film width direction are also deteriorated. On the other hand, when the take-up tension is 300 N / m or more, the variation of the orientation angle in the film width direction is deteriorated, and the width yield (taken efficiency in the width direction) is deteriorated.

  In the present embodiment, it is preferable to control the fluctuation of the take-up tension T with an accuracy of less than ± 5%, preferably less than ± 3%. When the variation in the take-up tension T is ± 5% or more, the variation in the optical characteristics in the width direction and the flow direction (conveying direction) increases. As a method for controlling the fluctuation of the take-up tension T within the above range, the load applied to the first roll (guide roll 56) on the outlet side of the stretching section 55, that is, the film tension is measured, and the value becomes constant. Thus, there is a method of controlling the rotation speed of the take-up roll or the take-up roll of the film take-up portion 59 by a general PID control method. Examples of the method for measuring the load include a method in which a load cell is attached to the bearing portion of the guide roll 56 and the load applied to the guide roll 56, that is, the tension of the film is measured. As the load cell, a known tensile type or compression type can be used.

  The stretched film is released from the exit of the stretching section 55 after being gripped by the gripping tool of the stretching section 55, and both ends (both sides) of the film gripped by the gripping tool are trimmed as necessary. Then, the film is cut into a predetermined length by the film cutting device 58, and is wound up around a winding core (winding roll) sequentially to form a wound body of an obliquely stretched film.

  Further, before winding the obliquely stretched film, for the purpose of preventing blocking between the films, the masking film may be overlapped with the obliquely stretched film and simultaneously wound, or at least one of the obliquely stretched films overlapping by winding (preferably May be wound up with a tape or the like attached to both ends. The masking film is not particularly limited as long as it can protect the obliquely stretched film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

(Details of stretched part)
Next, the detail of the extending | stretching part 55 mentioned above is demonstrated. FIG. 7 is a plan view schematically showing an example of the rail pattern of the extending portion 55. However, this is an example, and the configuration of the extending portion 55 is not limited to this.

  The production of the long obliquely stretched film in the present embodiment is performed using a tenter (an obliquely stretching machine) capable of oblique stretching as the stretching part 55. This tenter is an apparatus that heats a long film to an arbitrary temperature at which it can be stretched and obliquely stretches it. The tenter includes a heating zone Z, a pair of rails Ri and Ro on the left and right sides, and a number of grippers Ci and Co that travel along the rails Ri and Ro to convey a film (in FIG. 7, a set of grippers). Only). Details of the heating zone Z will be described later. Each of the rails Ri and Ro is configured by connecting a plurality of rail portions with connecting portions (white circles in FIG. 7 are examples of connecting portions). The gripping tool Ci / Co is composed of a clip that grips both ends of the film in the width direction.

  In FIG. 7, the feeding direction D1 of the long film is different from the winding direction D2 of the long oblique stretched film after stretching, and forms a feeding angle θi with the winding direction D2. The feeding angle θi can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.

  Thus, since the feeding direction D1 and the winding direction D2 are different, the rail pattern of the tenter has an asymmetric shape on the left and right. And a rail pattern can be adjusted now manually or automatically according to the orientation angle | corner (theta) given to the long diagonally stretched film which should be manufactured, a draw ratio, etc. FIG. In the oblique stretching machine used in the manufacturing method of the present embodiment, it is preferable that the positions of the rail portions and the rail connecting portions constituting the rails Ri and Ro can be freely set and the rail pattern can be arbitrarily changed.

  In the present embodiment, the tenter gripping tool Ci · Co travels at a constant speed with a constant distance from the front and rear gripping tools Ci · Co. The traveling speed of the gripping tool Ci / Co can be selected as appropriate, but is usually 1 to 150 m / min. The difference in travel speed between the pair of left and right grippers Ci / Co is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed on the left and right of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the left and right grippers Ci / Co is substantially the same speed. Is required. In general tenter devices, etc., there are speed irregularities that occur on the order of seconds or less depending on the period of the sprocket teeth that drive the chain, the frequency of the drive motor, etc. This does not correspond to the speed difference described in the embodiment of the invention.

  In the oblique stretching machine used in the manufacturing method of the present embodiment, a rail that regulates the trajectory of the gripping tool is often required to have a high bending rate, particularly in a portion where the film is transported obliquely. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws a curve at the bent portion.

  As described above, the obliquely stretched tenter used for imparting the oblique orientation to the long film can freely set the orientation angle of the film by changing the rail pattern in various ways, and further, the orientation axis of the film It is preferred that the tenter be capable of orienting the (slow axis) in the left and right direction with high precision across the film width direction and controlling the film thickness and retardation with high precision.

  Next, the extending | stretching operation | movement in the extending | stretching part 55 is demonstrated. Both ends of the long film are gripped by the left and right grippers Ci · Co, and are conveyed in the heating zone Z as the grippers Ci • Co travel. The left and right gripping tools Ci and Co are opposed to a direction substantially perpendicular to the film traveling direction (feeding direction D1) at the entrance portion (position A in the drawing) of the extending portion 55, and the left and right asymmetric rails. Each travels on Ri and Ro, and the film gripped at the exit portion (position B in the figure) at the end of stretching is released. The film released from the gripping tool Ci · Co is wound around the core by the film winding portion 59 described above. Each of the pair of rails Ri and Ro has an endless continuous track, and the grippers Ci and Co that have released the film at the exit portion of the tenter travel on the outer rail and sequentially return to the entrance portion. It is supposed to be.

  At this time, since the rails Ri and Ro are asymmetrical in the left and right directions, in the example of FIG. 7, the left and right gripping tools Ci and Co, which are opposed to each other at the position A in the figure, move as the rails run on the rails Ri and Ro. The gripping tool Ci traveling on the Ri side (in-course side) has a positional relationship preceding the gripping tool Co traveling on the rail Ro side (out-course side).

  That is, of the gripping tools Ci and Co that are opposed to the film feeding direction D1 at the position A in the figure, one gripping tool Ci is first in position B at the end of film stretching. When it reaches, the straight line connecting the gripping tools Ci and Co is inclined by an angle θL with respect to the direction substantially perpendicular to the film winding direction D2. With the above operation, the long film is obliquely stretched at an angle of θL with respect to the width direction. Here, “substantially vertical” indicates that the angle is in a range of 90 ± 1 °.

  Next, the details of the heating zone Z will be described. The heating zone Z of the extending section 55 is composed of a preheating zone Z1, an extending zone Z2, and a heat setting zone Z3. In the stretching unit 55, the film gripped by the gripping tool Ci / Co passes through the preheating zone Z1, the stretching zone Z2, and the heat fixing zone Z3 in this order. In the present embodiment, the preheating zone Z1 and the stretching zone Z2 are separated by a partition, and the stretching zone Z2 and the heat fixing zone Z3 are separated by a partition.

  The preheating zone Z1 refers to a section in which the gripping tool Ci / Co that grips both ends of the film travels at the left and right (in the film width direction) while maintaining a constant interval at the entrance of the heating zone Z.

  The stretching zone Z2 refers to a section in which the gap between the gripping tools Ci and Co that grips both ends of the film opens and reaches a predetermined interval. At this time, the oblique stretching as described above is performed, but the stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching as necessary.

  The heat setting zone Z3 refers to a section after the stretching zone Z2 in which the interval between the gripping tools Ci and Co is constant, and the gripping tools Ci and Co at both ends travel in parallel with each other. .

  The stretched film passes through the heat setting zone Z3 and then passes through a section (cooling zone) in which the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg (° C.) of the thermoplastic resin constituting the film. May be. At this time, considering the shrinkage of the film due to cooling, a rail pattern that narrows the gap between the gripping tools Ci and Co facing each other in advance may be used.

  With respect to the glass transition temperature Tg of the thermoplastic resin, the temperature of the preheating zone Z1 is Tg to Tg + 30 ° C., the temperature of the stretching zone Z2 is Tg to Tg + 30 ° C., and the temperature of the heat setting zone Z3 and the cooling zone is Tg-30 to Tg + 20 ° C. It is preferable to set.

  The lengths of the preheating zone Z1, the stretching zone Z2, and the heat setting zone Z3 can be appropriately selected. The length of the preheating zone Z1 is usually 100 to 150% of the length of the stretching zone Z2, and the length of the heat setting zone Z3. The length is usually 50-100%.

  When the width of the film before stretching is Wo (mm) and the width of the film after stretching is W (mm), the draw ratio R (W / Wo) in the stretching step is preferably 1.3 to 3. 0, more preferably 1.5 to 2.8. When the draw ratio is in this range, the thickness unevenness in the width direction of the film is preferably reduced. In the stretching zone Z2 of the oblique stretching tenter, if the stretching temperature is differentiated in the width direction, the width direction thickness unevenness can be further improved. In addition, said draw ratio R is equal to a magnification (W2 / W1) when the interval W1 between both ends of the clip held at the tenter inlet portion becomes the interval W2 at the tenter outlet portion.

  Note that the method of oblique stretching in the stretching portion 55 is not limited to the above-described method. For example, even if oblique stretching is performed by simultaneous biaxial stretching as disclosed in Japanese Patent Application Laid-Open No. 2008-23775. Good. Note that simultaneous biaxial stretching means that both ends in the width direction of the supplied long film are gripped by each gripping tool, and the long film is transported while moving each gripping tool, and the long film is transported. This is a method of stretching a long film in an oblique direction with respect to the width direction by making the moving speed of one gripping tool different from the moving speed of the other gripping tool while keeping the direction constant. In addition, oblique stretching may be performed by a method as disclosed in JP 2011-11434 A.

  In the obliquely stretched film, the orientation angle θ is inclined in the range of, for example, 10 ° to 80 ° with respect to the winding direction, and the variation in the in-plane retardation Ro in the width direction is 4 nm or less in a width of at least 1300 mm. The variation of the orientation angle θ is preferably 1.0 ° or less.

  The variation of the in-plane retardation Ro of the obliquely stretched film is 4 nm or less, preferably 3 nm or less, at least 1300 mm in the width direction. By setting the variation of the in-plane retardation Ro within the above range, the display quality can be improved when used as a retardation film for a liquid crystal display device.

  The variation in the orientation angle θ of the obliquely stretched film is 1.0 ° or less, preferably 0.80 ° or less, at least 1300 mm in the width direction. When a stretched film having a variation in the orientation angle θ exceeding 1.0 ° is bonded to a polarizing plate to obtain a circularly polarizing plate, and this is installed in a liquid crystal display device, light leakage may occur and the contrast may be lowered.

  The in-plane retardation Ro of the obliquely stretched film is selected as the optimum value depending on the design of the display device used. Note that Ro is a value obtained by multiplying the difference between the refractive index nx in the in-plane slow axis direction and the refractive index ny in the direction perpendicular to the slow axis by the average thickness d of the film (Ro = (nx −ny) × d).

  The average thickness of the obliquely stretched film is preferably 20 to 80 μm from the viewpoint of mechanical strength and the like. Moreover, since the thickness unevenness in the width direction affects the uniformity of the film elastic modulus and the possibility of winding, the thickness is preferably 3 μm or less.

(Physical properties of film substrate)
As for the film thickness of a film base material, 1-200 micrometers is preferable, More preferably, it is 1-80 micrometers, More preferably, it is 1 micrometer or more and less than 30 micrometers. Moreover, 500-10000m is preferable and, as for the length of a film base material, More preferably, it is 1000-8000m. By setting it as the range of the said length, it is excellent in the processability in application | coating of a functional layer etc., and the handleability of film base itself.

  Moreover, arithmetic mean roughness Ra of a film base material becomes like this. Preferably it is 2-10 nm, More preferably, it is 2-5 nm. The arithmetic average roughness Ra can be measured according to JIS B0601: 1994.

[Winding]
The thickness of the air layer held between the layers when the hard coat film and the film substrate of the present embodiment are rolled up is preferably in the range of 0.5 to 10 μm, more preferably in the range of 1 to 5 μm. It is. The thickness t ′ of the air layer is a value obtained from an equation of t ′ = [{π (D ² −d ² ) / 4L} −t]. In the above formula, D represents the winding diameter, d represents the winding core diameter, L represents the winding length, and t represents the thickness of the film.

  In addition, as a method for winding a hard coat film, etc., a roller for touching the film is provided in front of the take-up shaft, and the film is taken up, and when the film is taken up on the take-up shaft, The method of winding the film while the roller to be touched is gradually separated at regular intervals (gap winding), and when the film is wound around the core by rotating the core, the film is constant in the width direction of the film on the core An oscillating winding method that winds while periodically shifting within a range can be used. The thickness of the air layer can be controlled by adjusting the winding conditions described above, such as the tension condition during winding.

[Other layers]
In the hard coat film of this embodiment, other layers such as an antireflection layer and a conductive layer can be provided on the functional layer.

(Antireflection layer)
The hard coat film of this embodiment can be used as an antireflection film having an external light antireflection function by coating an antireflection layer on a functional layer.

  The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is composed of a low refractive index layer having a lower refractive index than the protective film as the support, or a combination of a high refractive index layer and a low refractive index layer having a higher refractive index than the protective film as the support. Preferably it is.

(Low refractive index layer)
The low refractive index layer preferably contains silica-based fine particles, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and a wavelength of 550 nm.

  The film thickness of the low refractive index layer is preferably in the range of 5 nm to 0.5 μm, more preferably in the range of 10 nm to 0.3 μm, and in the range of 30 nm to 0.2 μm. Most preferred.

The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and porous or hollow inside are preferably hollow silica-based fine particles. The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.
General formula (OSi-1): Si (OR) ₄
In the formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary. Further, it may contain a compound having a thermosetting property and / or a photocuring property mainly containing a fluorine-containing compound containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group. . Specifically, it is a fluorine-containing polymer or a fluorine-containing sol-gel compound. Examples of the fluorine-containing polymer include, in addition to hydrolysates and dehydration condensates of perfluoroalkyl group-containing silane compounds (for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane), fluorine-containing monomers. Examples thereof include fluorine-containing copolymers having units and cross-linking reactive units as constituent units.

(High refractive index layer)
The refractive index of the high refractive index layer is preferably adjusted to a refractive index in the range of 1.4 to 2.2 by measuring at 23 ° C. and a wavelength of 550 nm. The thickness of the high refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. Adjustment of the refractive index can be achieved by adding metal oxide fine particles and the like. The metal oxide fine particles used preferably have a refractive index of 1.80 to 2.60, more preferably 1.85 to 2.50.

  The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from can be used.

(Conductive layer)
In the hard coat film, a conductive layer may be formed on the functional layer. As the conductive layer provided, a generally well-known conductive material can be used. For example, metal oxides such as indium oxide, tin oxide, indium tin oxide, gold, silver, and palladium can be used. These can be formed as a thin film on the hard coat film by vacuum deposition, sputtering, ion plating, solution coating, or the like. Moreover, it is also possible to form a conductive layer using the organic conductive material which is the above-described π-conjugated conductive polymer.

  In particular, a conductive material that is excellent in transparency and conductivity, and that has a main component of any of indium oxide, tin oxide, and indium tin oxide, which can be obtained at a relatively low cost, can be suitably used. Although the thickness of the conductive layer varies depending on the material to be applied, it cannot be said unconditionally. However, the surface resistivity is 1000Ω or less, preferably 500Ω or less, and considering the economy, A range of 10 nm or more, preferably 20 nm or more and 80 nm or less, preferably 70 nm or less is suitable. In such a thin film, visible light interference fringes due to uneven thickness of the conductive layer are unlikely to occur.

〔Polarizer〕
A polarizing plate using the hard coat film of this embodiment will be described. The polarizing plate can be produced by a general method.

  For example, a completely saponified polyvinyl alcohol is formed on at least one surface of a polarizing film (polarizer) produced by subjecting the hard coat film of the present embodiment to an alkali saponification treatment and immersing and stretching the treated hard coat film in an iodine solution. It is preferable to bond using an aqueous solution.

  A substrate film such as the cellulose ester film described above may be bonded to the other surface of the polarizing film. The film thickness of the base film used for the other surface is preferably in the range of 5 to 80 μm from the viewpoint of adjusting smoothness and curl balance and further enhancing the effect of preventing winding deviation.

  A polarizing film, which is a main component of the polarizing plate, is an element that allows only light having a polarization plane in a certain direction to pass through. A typical polarizing film known at present is a polyvinyl alcohol polarizing film. Examples of the polarizing film include those obtained by dyeing iodine on a polyvinyl alcohol film and those obtained by dyeing a dichroic dye, but are not limited thereto.

  As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxial stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. The thickness of the polarizing film is 5 to 30 μm, preferably 8 to 15 μm.

  On the surface of the polarizing film, one side of the hard coat film of the present embodiment is bonded to form a polarizing plate. Preferably, they are bonded together with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Circularly polarizing plate)
A circularly polarizing plate can also be used as the polarizing plate. The circularly polarizing plate can be constituted by laminating a polarizing plate protective film, a polarizer, and a λ / 4 film in this order. In this case, the angle formed between the slow axis of the λ / 4 film and the absorption axis (or transmission axis) of the polarizer is 45 °. A long polarizing plate protective film, a long polarizer, and a long λ / 4 film (long diagonally stretched film) are preferably laminated in this order.

  The circularly polarizing plate can be produced by using a stretched polyvinyl alcohol doped with iodine or a dichroic dye as a polarizer, and laminating with a configuration of λ / 4 film / polarizer. The film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

  The polarizing plate can be produced by a general method. The λ / 4 film subjected to the alkali saponification treatment is preferably bonded to one surface of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution.

(Adhesive layer)
The pressure-sensitive adhesive layer used on one side of the film to be bonded to the substrate of the liquid crystal cell is preferably optically transparent and exhibits moderate viscoelasticity and adhesive properties.

  Specific examples of the adhesive layer include adhesives or adhesives such as acrylic copolymers, epoxy resins, polyurethane, silicone polymers, polyethers, butyral resins, polyamide resins, polyvinyl alcohol resins, and synthetic rubbers. A film such as a drying method, a chemical curing method, a thermal curing method, a thermal melting method, a photocuring method, or the like can be formed and cured using a polymer such as the above. Among them, the acrylic copolymer can be preferably used because it is most easy to control the physical properties of the adhesive and is excellent in transparency, weather resistance, durability and the like.

[Image display device]
The hard coat film of this embodiment is preferable in that the performance excellent in visibility is exhibited by using it in an image display device. As an image display device, a reflection type, a transmission type, a semi-transmission type liquid crystal display device, a liquid crystal display device of various driving methods such as a TN type, an STN type, an OCB type, a VA type, an IPS type, an ECB type, a touch panel display device, Examples include an organic EL display device and a plasma display. Among these image display devices, a liquid crystal display device is preferable because of its high visibility.

  A polarizing plate composed of a hard coat film having a λ / 4 plate function exhibits excellent visibility in an image display device, and also has excellent crosstalk when the head is tilted during image viewing (prevents a decrease in luminance). From the point). Such an effect is particularly effective in a stereoscopic image display device that visually recognizes a stereoscopic image (3D image) through polarized glasses or an image display device that visually recognizes a normal image (2D image) through polarized sunglasses. It is done.

〔Example〕
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

[Production of Cellulose Ester Film 1]
<Preparation of silicon dioxide dispersion>
Aerosil R812 (Nippon Aerosil Co., Ltd., average primary particle diameter of 7 nm)
10 parts by mass Ethanol 90 parts by mass The above was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to prepare a silicon dioxide dispersion dilution. It filtered with the fine particle dispersion | distribution dilution liquid filter (Advantech Toyo Co., Ltd .: Polypropylene wind cartridge filter TCW-PPS-1N).

<Preparation of Dope Composition 1>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14000) 90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Polymer represented by General Formula (P) (Exemplary Compound P-01) 4 parts by mass (ultraviolet absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass The above was put into a sealed container, heated and stirred, and dissolved completely. Azumi filter paper No. Azumi filter paper No. 24 was used to prepare a dope (dope composition 1).

<Film formation of cellulose ester film 1>
Next, the dope composition 1 was uniformly cast on a stainless steel band support using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100% by mass, and the stainless steel band support was peeled off. Solvent contained in the web of cellulose ester film is evaporated at 35 ° C., slit to 1.15 m width, and stretched 1.15 times in the TD direction (the width direction of the film) with a tenter, and a drying temperature of 140 ° C. And dried. Then, it was dried for 15 minutes while being transported in a drying device at 120 ° C. with a number of rollers, slitted to a width of 1.3 m, knurled with a width of 10 mm and a height of 5 μm at both ends of the film, and wound around a core. The cellulose ester film 1 was obtained. The film thickness of the cellulose ester film 1 was 25 μm, and the winding length was 5000 m. In addition, the draw ratio of MD direction computed from the rotational speed of a stainless steel band support body and the driving speed of a tenter was 1.01 times.

[Preparation of Hard Coat Film 1]
The functional layer 1 (first functional layer) is formed on one surface of the produced cellulose ester film 1 and the functional layer 2 (second functional layer) is formed on the other surface. A roll-shaped hard coat film 1 was produced by winding the film so as to have a thickness of 3 μm. In addition, all the roll-shaped hard coat films produced below were wound up so that the thickness of the air layer was 3 μm. Details of the formation of the functional layer 1 and the formation of the functional layer 2 are as follows.

(Formation of functional layer 1)
The following functional layer composition 1 is applied on the side A of the produced cellulose ester film 1 (the side not in contact with the casting belt) using an extrusion coater, and the constant rate drying section temperature is reduced to 50 ° C. After drying at a rate drying zone temperature of 50 ° C., while purging with nitrogen so that the oxygen concentration is 1.0 volume% or less, the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp and the irradiation amount is 0 The coating layer was cured at ³ J / cm ² to form a functional layer 1 having a dry film thickness of 6 μm.

[Functional layer composition 1]
AUP-787 (manufactured by Tokushiki Co., Ltd.) 100 parts by weight Methyl ethyl ketone 50 parts by weight Propylene glycol monomethyl ether 30 parts by weight BYK-381 (acrylic copolymer, manufactured by BYK Japan Co., Ltd.)
1 part by mass AUP-787 is a resin composition containing urethane acrylate, a photopolymerization initiator, and methyl ethyl ketone.

(Formation of functional layer 2)
After the functional layer 1 is formed, the following functional layer composition 101 is applied onto the B side of the cellulose ester film 1 (the surface in contact with the casting belt) using an extrusion coater, and the constant rate drying section While purging with nitrogen so that the oxygen concentration is 1.0% by volume or less when drying at a temperature of 50 ° C. and a decreasing rate drying section temperature of 50 ° C., the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp, to cure the coating layer the amount of irradiation as 0.3 J / cm ^2, to form a functional layer 2 of the dry film thickness 4 [mu] m.

<Preparation of functional layer composition>
The functional layer composition 101 was adjusted as follows. That is, the following polymer silane coupling agent-coated silica (1) is added to the following solvent and dispersed with a Manton Gorin homogenizer, and then the following compound is added to the dispersion, followed by stirring and mixing to obtain a functional layer composition. 101 was adjusted.

[Functional layer composition 101]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 40 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (fine particles)
Polymer silane coupling agent-coated silica (1) 60 parts by mass (additive)
BYK-UV3510 (polyether-modified silicone, manufactured by Big Chemie Japan Co., Ltd.) 1 part by mass (solvent)
Propylene glycol monomethyl ether 50 parts by weight Methyl acetate 50 parts by weight

<Preparation of silica coated with polymer silane coupling agent>
Adjustment of said polymer silane coupling agent coating | coated silica (1) was performed as follows.

In a container, 30 ml of methyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd .: Light Ester M), 1 ml of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-803), 100 ml of tetrahydrofuran as a solvent, polymerization initiator Was added 50 mg of azoisobutyronitrile (manufactured by Kanto Chemical Co., Inc .: AIBN) and substituted with N ₂ gas, and then heated at 80 ° C. for 3 hours to prepare a polymer silane coupling agent. The obtained polymer silane coupling agent had a molecular weight of 16,000. The molecular weight was measured with a gel permeation chromatography apparatus.

Next, silica sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: Si-45P, SiO ₂ concentration 30% by weight, average particle diameter 45 nm, dispersion medium: water) is ion-exchanged with an ion exchange resin, and an ultrafiltration membrane method is used. The solvent of water was replaced with ethanol to prepare 100 g of an ethanol dispersion of silica fine particles (SiO ₂ concentration of 30% by weight).

  100 g of the silica fine particle ethanol dispersion and 1.5 g of the polymer silane coupling agent are dispersed in 20 g (25 ml) of acetone, and 20 mg of aqueous ammonia having a concentration of 29.8% by weight is added thereto, followed by stirring at room temperature for 30 hours. The polymer silane coupling agent was adsorbed on the silica fine particles.

  Thereafter, silica particles having an average particle diameter of 5 μm are added and stirred for 2 hours to adsorb the unadsorbed polymer silane coupling agent in the solution to the silica particles, and then the polymer silane coupling that has not been adsorbed by centrifugation. Silica particles having an average particle diameter of 5 μm adsorbing the agent were removed. 1000 g of ethanol is added to the silica fine particle dispersion adsorbing the polymer silane coupling agent, and the silica fine particles are precipitated, separated, dried under reduced pressure, and then dried at 25 ° C. for 8 hours to obtain a polymer silane coupling agent-coated silica (1 ) The obtained polymer silane coupling agent-coated silica (1) had an average particle size of 57 nm. The average particle size was measured with a laser particle size measuring device.

<Preparation of hard coat film 2>
A roll-shaped hard coat film 2 was prepared in the same manner as the hard coat film 1 except that the dry film thickness of the functional layer 1 was changed to 16 μm.

<Preparation of hard coat film 3>
A roll-shaped hard coat film 3 was prepared in the same manner as the hard coat film 1 except that the dry film thickness of the functional layer 1 was changed to 26 μm.

<Preparation of hard coat film 4>
The functional layer 2 was formed by changing the functional layer composition 101 to the following functional layer composition 102. Other than that was carried out similarly to preparation of the hard coat film 2, and the roll-shaped hard coat film 4 was produced.

<Preparation of functional layer composition>
The following compound was stirred and mixed to prepare the functional layer composition 102.

[Functional layer composition 102]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 100 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (additive)
Fluorine-siloxane graft compound (35% by mass) 2 parts by mass (solvent)
Propylene glycol monomethyl ether 50 parts by weight Methyl acetate 50 parts by weight

  The commercial product names of the materials used for the preparation of the fluorine-siloxane graft compound are as follows.

Radical polymerizable fluororesin (A): Cefal coat CF-803 (hydroxy group number 60, number average molecular weight 15000; manufactured by Central Glass Co., Ltd.)
Single-end radical polymerizable polysiloxane (B): Silaplane FM-0721 (number average molecular weight 5000; manufactured by Chisso Corporation)
Radical polymerization initiator: Perbutyl O (t-butylperoxy-2-ethylhexanoate; manufactured by NOF Corporation)
Curing agent: Sumidur N3200 (biuret type prepolymer of hexamethylene diisocyanate; manufactured by Sumika Bayer Urethane Co., Ltd.)

<Preparation of fluorine-siloxane graft compound>
A radically polymerizable fluororesin (26.1 parts by mass) and xylene (19.5 parts by mass) synthesized as described below in a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet. Part), n-butyl acetate (16.3 parts by weight), methyl methacrylate (2.4 parts by weight), n-butyl methacrylate (1.8 parts by weight), lauryl methacrylate (1.8 parts by weight), 2-hydroxy Ethyl methacrylate (1.8 parts by mass), FM-0721 (5.2 parts by mass), and perbutyl O (0.1 parts by mass) were added, heated to 90 ° C. in a nitrogen atmosphere, and then at 90 ° C. for 2 hours. Retained. Perbutyl O (0.1 part) was added, and the solution was further maintained at 90 ° C. for 5 hours to obtain a 35 mass% fluorine-siloxane graft compound solution having a weight average molecular weight of 171,000. The weight average molecular weight was determined by GPC. Moreover, the mass% of the fluorine-siloxane graft compound was calculated | required by HPLC (liquid chromatography).

<Synthesis of radically polymerizable fluororesin>
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, cefal coat CF-803 (1554 parts by mass), xylene (233 parts by mass), and 2-isocyanatoethyl methacrylate (6 3 parts by mass) and heated to 80 ° C. in a dry nitrogen atmosphere. After reacting at 80 ° C. for 2 hours and confirming that the absorption of isocyanate disappeared by the infrared absorption spectrum of the sampled material, the reaction mixture was taken out to obtain 50% by mass of a radically polymerizable fluororesin via a urethane bond. .

<Preparation of hard coat film 5>
The functional layer composition 1 was changed to the following functional layer composition 2 to form the functional layer 1. Other than that was carried out similarly to preparation of the hard coat film 2, and the roll-shaped hard coat film 5 was produced.

[Functional layer composition 2]
Pandex GW-3250 (manufactured by DIC Corporation) 100 parts by mass Methyl ethyl ketone 50 parts by mass Propylene glycol monomethyl ether 50 parts by mass BYK-381 (acrylic copolymer, manufactured by Big Chemie Japan Co., Ltd.)
1 part by mass Note that Pandex GW-3250 is a resin composition containing urethane acrylate, a photopolymerization initiator, and methyl ethyl ketone.

<Preparation of hard coat film 6>
On the functional layer 1 of the hard coat film 2 produced above, the following functional layer composition 3 filtered through a polypropylene filter having a pore diameter of 0.4 μm was applied using a micro gravure coater, and the constant rate After drying at a drying zone temperature of 80 ° C. and a reduced rate drying zone temperature of 80 ° C., the irradiance of the irradiated part is 100 mW / cm using an ultraviolet lamp while purging with nitrogen so that the oxygen concentration becomes 1.0% by volume or less. ² , the application layer was cured with an irradiation dose of 0.35 J / cm ² , and the functional layer 3 having a dry film thickness of 0.25 μm was formed. Then, the film was wound up in a roll shape to obtain a hard coat film 6. That is, in the hard coat film 6, the first functional layer was composed of two layers of the functional layer 1 and the functional layer 3.

[Functional layer composition 3]
Dipentaerythritol penta and hexaacrylate (NK ester A-9550, manufactured by Shin-Nakamura Chemical Co., Ltd.) 100 parts by mass Irgacure 184 (manufactured by Ciba Japan Co., Ltd.) 5 parts by mass BYK-381 1 part by mass Propylene glycol monomethyl ether 10 parts by mass Methyl acetate 45 parts by mass Methyl ethyl ketone 45 parts by mass

<Preparation of hard coat film 7>
A roll-like hard coat film 7 was produced in the same manner as the production of the hard coat film 6 except that the dry film thickness of the functional layer 3 was changed to 3 μm.

<Preparation of hard coat film 8>
On the functional layer 1 of the hard coat film 5 produced above, the functional layer composition 1 filtered through a polypropylene filter having a pore size of 0.4 μm is applied to the surface using a micro gravure coater, and dried at a constant rate. After drying at a section temperature of 80 ° C. and a reduced rate drying section temperature of 80 ° C., the irradiance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0 volume% or less. Then, the coating layer was cured with an irradiation dose of 0.3 J / cm ² to form a functional layer 3 having a dry film thickness of 11 μm. Thereafter, the film was wound up in a roll shape to obtain a hard coat film 8. That is, in the hard coat film 8, the first functional layer was composed of two layers of the functional layer 1 made of the functional layer composition 2 and the functional layer 3 made of the functional layer composition 1.

<Preparation of hard coat film 9>
The functional layer composition 1 was changed to the functional layer composition 3, and the functional layer 1 was formed by changing the ultraviolet irradiation amount to 0.03 J / cm ² . Other than that was carried out similarly to preparation of the hard coat film 2, and the roll-shaped hard coat film 9 was produced.

<Preparation of hard coat film 10>
A roll-shaped hard coat film 10 was produced in the same manner as the hard coat film 9 except that the functional layer 1 was formed by changing the ultraviolet irradiation amount to 0.07 J / cm ² .

<Preparation of hard coat film 11>
In the production of the hard coat film 2, the functional layer 2 was not formed, and the functional layer composition 1 was changed to the following functional layer composition 4 to form the functional layer 1. Other than that was carried out similarly to preparation of the hard coat film 2, and the roll-shaped hard coat film 11 was produced.

[Functional layer composition 4]
AUP-787 (manufactured by Tokushi Co., Ltd.) 100 parts by mass Polymer silane coupling agent-coated silica (1) 10 parts by mass (additive)
Methyl ethyl ketone 50 parts by mass Propylene glycol monomethyl ether 30 parts by mass BYK-381 (acrylic copolymer, manufactured by BYK Japan Co., Ltd.)
1 part by mass

<Preparation of hard coat film 12>
In preparation of the hard coat film 2, the functional layer composition 1 was changed to the functional layer composition 4 to form the functional layer 1. Other than that was carried out similarly to preparation of the hard coat film 2, and the roll-shaped hard coat film 12 was produced.

<Durability test>
Each of the produced roll-shaped hard coat films 1 to 12 was wrapped in an aluminum moisture-proof sheet and stored for 25 days in a thermostatic bath at 50 ° C. and a relative humidity of 80% assuming long-term transportation. After storage for 25 days, a polarizing plate was produced by the following method.

<Preparation of Polarizing Plate 101>
The hard coat film 1 after the durability test is attached to one surface of the polarizing film, and a protective film made of KC4FR-1 (manufactured by Konica Minolta Co., Ltd.), which is an optical compensation film, is attached to the other surface of the polarizing film. A polarizing plate 101 was produced. More details are as follows.

(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400. After melt-kneading and defoaming, it was melt-extruded from a T-die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m.

  Next, the obtained PVA film was continuously processed in the order of preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of polarizing plate A polarizing plate 101 was produced by bonding the polarizing film, the protective film (KC4FR-1) and the hard coat film 1 after the durability test in accordance with the following steps 1 to 5.

  Process 1: The above-mentioned polarizing film was immersed for 1 to 2 seconds in the storage tank of the polyvinyl alcohol adhesive agent solution of 2 mass% of solid content.

Process 2: The alkali saponification process was implemented on the hard coat film 1 and protective film which affixed the peelable protective film (product made from PET) to the functional layer 1 on condition of the following. Next, excess adhesive adhered to the polarizing film immersed in the polyvinyl alcohol adhesive solution in Step 1 was lightly removed, and this polarizing film was sandwiched between the hard coat film 1 and the protective film, and laminated.
(Alkaline saponification treatment)
Saponification step 2.5M-KOH 50 ° C. 120 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts by mass HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds After saponification treatment, water washing, neutralization, water washing in this order Followed by drying at 100 ° C.

Step 3: The above laminate was bonded at a speed of about 2 m / min at a pressure of ^{20 to} 30 N / cm ² with two rotating rollers. At this time, it was carried out with care to prevent bubbles from entering.

  Step 4: The sample prepared in Step 3 was dried in a dryer at a temperature of 100 ° C. for 5 minutes to prepare a polarizing plate.

  Step 5: A commercially available acrylic pressure-sensitive adhesive is applied to the protective film side of the polarizing plate prepared in Step 4 so that the thickness after drying is 25 μm, and dried in an oven at 110 ° C. for 5 minutes to form an adhesive layer. A peelable protective film was attached to the adhesive layer. This polarizing plate was cut (punched) to produce a polarizing plate 101.

<Preparation of polarizing plates 102-112>
Polarizing plates 102 to 112 were prepared in the same manner as the polarizing plate 101 except that the hard coat film 1 was changed to the hard coat films 2 to 12 subjected to the durability test.

<Production of Liquid Crystal Display Device 201>
Of the two polarizing plates sandwiching the liquid crystal cell of Sony liquid crystal television (KDL-40HX700), the viewing side polarizing plate was peeled off. Next, the polarizing plate 101 prepared above has a viewing side of the liquid crystal cell such that the functional layer 1 is on the viewing side and the transmission axis of the polarizing plate 101 and the transmission axis of the polarizing plate on the backlight side are orthogonal to each other. Arranged. And the adhesive layer of the polarizing plate 101 and the glass of the liquid crystal cell were bonded together, and the liquid crystal display device 201 was produced.

<Production of liquid crystal display devices 202 to 212>
Liquid crystal display devices 202 to 212 were fabricated in the same manner as the liquid crystal display device 201 except that the polarizing plate 101 was changed to the polarizing plates 102 to 112, respectively.

<Evaluation>
About the produced said hard coat films 1-12 and the liquid crystal display devices 201-212, the following content was evaluated.

<Hard coat film>
・ Indentation depth setting load using microhardness meter-Unloading test For each of the hard coat films 1-12 produced above, a microhardness meter using a Vickers indenter and a triangular pyramid indenter with an angle between ridges of 115 degrees (product) Name, DUH-211S, manufactured by Shimadzu Corporation), and the indentation depth hmax (μm) by applying a test force to the surface of the functional layer 1 or the surface of the functional layer 3 of each hard coat film After the indenter was pushed in, the load was removed, and a load test force-indentation depth curve (see FIG. 5) was created. And about each hard coat film 1-12, the following value A was computed from the residual depths h1 and h2 calculated | required when measuring by unloading holding time 0 second and 60 second.
A = (h1-h2) / hmax
However,
h1: Residual depth (μm) when measured with an unloading retention time of 0 seconds
h2: Residual depth (μm) when measured with an unloading holding time of 60 seconds
hmax: Setting push-in depth (μm)
It is. Table 1 shows the value of A obtained for each of the hard coat films 1 to 12.

・ Measurement of water contact angle (θ)
The water contact angle (θ) of the surface of the hard coat films 1 to 12 opposite to the side on which the first functional layer is formed (the surface when the second functional layer is formed) is as follows. It was measured. That is, a sample was left for 24 hours in an atmosphere of 23 ° C. and 55% relative humidity, and then contact angle meter (trade name DropMaster DM100, manufactured by Kyowa Interface Science Co., Ltd.) in an atmosphere of 23 ° C. and 55% relative humidity. Was used to measure the contact angle of pure water 1 minute after dropping 1 μL of pure water. In addition, the measurement was performed seven times, and the average value of the five measurement values excluding the maximum value and the minimum value of the measurement value was used as the contact angle of the sample. The obtained result (θ) is shown in Table 1.

Arithmetic average roughness Ra Optical interference type surface roughness of the first functional layer (functional layer 1 or functional layer 3) or the second functional layer (functional layer 2) of the hard coat films 1 to 12 The surface roughness was measured 10 times using a meter (manufactured by ZYGO, NewView 5030), and the arithmetic average roughness Ra of the first functional layer or the second functional layer was determined from the average of the measurement results. The obtained results are shown in Table 1.

<Liquid crystal display device>
In the liquid crystal display devices 201 to 212, the display unevenness caused by the distortion of the hard coat films 1 to 12 and the visibility caused by the flatness of the hard coat films 1 to 12 were evaluated.

Evaluation of display unevenness due to distortion Each of the produced liquid crystal display devices 201 to 212 was observed from the front in black display, and display unevenness due to distortion was evaluated based on the following criteria.
(Evaluation criteria)
A: Display unevenness due to deformation is not recognized at all.
○: Display unevenness due to deformation is slightly observed, but there is no problem in practical use.
(Triangle | delta): The display nonuniformity resulting from a fine deformation | transformation is recognized, and a problem in actual use may arise.
X: Display unevenness due to deformation is clearly recognized, which is a problem in practical use.

-Visibility evaluation due to flatness Each of the liquid crystal display devices 201 to 212 produced above has an evaluator such that the long side direction of the display surface is parallel to the long direction of the straight fluorescent lamp on the ceiling. Is placed on a desk with a height of 80 cm from the floor so that the fluorescent lamp on the ceiling is located behind the evaluator's head and behind the display surface of the liquid crystal display device. Here, the above-mentioned straight tube fluorescent lamp is a daylight direct tube fluorescent lamp (FLR40S • D / MX manufactured by Panasonic Corporation). One set includes 40W × 2 and 10 sets at 1.5 m intervals. In parallel, it is placed on the ceiling 3m high from the floor. Then, an evaluator is positioned in front of the display surface of the liquid crystal display device, the image of the fluorescent lamp is observed by reflection on the display surface, and the visibility due to the flatness of the hard coat film is based on the following criteria: And evaluated.
(Evaluation criteria)
A: The fluorescent lamp looks straight.
○: Some fluorescent lamps appear to be bent slightly.
Δ: The fluorescent lamp appears to be bent.
X: A fluorescent lamp appears to swell greatly.

  In each liquid crystal display device, the evaluation results of the visibility due to display unevenness and flatness due to the distortion of the hard coat film are shown in Table 1. Table 1 also shows the correspondence between the examples and the comparative examples.

  From Table 1, in the liquid crystal display device using the hard coat film of Examples 1-9 (hard coat films 1-3, 5, 6, 8, 10, 11, 12), the distortion of the hard coat film after the durability test. It can be seen that there is almost no display unevenness due to, and there is almost no deterioration in visibility due to the flatness deterioration of the hard coat film. This is because the first functional layer (the functional layer 1 alone or the laminate of the functional layer 1 and the functional layer 3) is formed on one surface of the film substrate, and the first functional layer is pushed in. The value A obtained by the depth setting load-unloading test is 0.02 or more and 0.90 or less, and the arithmetic average roughness Ra of the surface of the first functional layer (the first surface on the other surface of the film substrate) In the case of having a bifunctional layer, the arithmetic average roughness Ra) of at least one surface of the first functional layer and the second functional layer is 2 nm or more. Even when the thickness of the film substrate is as thin as 25 μm in the configuration using the film, the effect of preventing the sticking between the films when wound up in a roll shape is sufficiently obtained, and distortion caused by sticking of the film It is thought that the deterioration of flatness is sufficiently suppressedIn addition, although the surface of the 1st functional layer of the hard coat film of Examples 1-9 was rubbed back and forth 10 times with a brass brush, a scratch was generated.

  In addition, in the comparative example 1 in which the arithmetic surface roughness Ra of the first functional layer and the second functional layer is 1 nm, the evaluation result of visibility due to display unevenness due to distortion and flatness deterioration is x. Yes, in Example 1 where Ra is 20 nm, it is ◯, so if Ra is 10 nm or more between these values, it can be said that the effect of preventing film sticking at the time of winding is high, and if it is 20 nm or more It can be said that the effect becomes even higher. Even if the lower limit of Ra is smaller than 10 nm as described above, it is considered that the above effect can be expected if it is 2 nm or more, which is larger than the value (1 nm) in Comparative Example 1.

  Further, the lower limit of the value A is smaller than the value (0.13) in Example 1, but is 0.02 or more, which is larger than the value (0.01) in Comparative Example 1, The effect is expected. Regarding the upper limit of the value A, a value (0.90) between the value (0.86) in Example 7 and the value (0.95) in Comparative Example 3 is considered appropriate.

  In addition, each evaluation of display unevenness due to distortion and visibility due to flatness is “◯” in Example 1 and “◎” in Example 2. Therefore, the value A described above is By providing a second functional layer having an anti-blocking property if the value (0.20) or more between the value (0.13) at 1 and the value (0.26) in Example 2 is not less than It can be said that the sticking prevention effect is high. In addition, when the value A is 0.20 or more, self-healing characteristics are reliably imparted to the first functional layer. From the above, it can be said that the value A is preferably 0.20 or more and 0.90 or less.

  Moreover, like Example 1-9, the other surface of a film base material or the 2nd functional layer has the surface characteristic (water contact angle of 95 degrees or less) which shows hydrophilic property, The film at the time of winding It is easy to obtain an anti-sticking effect, and even when used in a liquid crystal display device after an endurance test, it is understood that there is no display unevenness due to deterioration in visibility and distortion due to deterioration in flatness and excellent visibility. .

<Preparation of hard coat film 13>
A roll-shaped hard coat film 13 was produced in the same manner as in the production of the hard coat film 2 except that the functional layer composition 101 of the functional layer 2 was changed to the following functional layer composition 103. The functional layer composition 103 was prepared by stirring and mixing the following compounds.

[Functional layer composition 103]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 95 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (fine particles)
NANOBYK-3650 (Solvent-dispersed silica particles, average particle shape 20 nm, silica content 25%, manufactured by Big Chemie Japan Co., Ltd.) 20 parts by mass (additive)
BYK-UV3510 (polyether-modified silicone, manufactured by Big Chemie Japan Co., Ltd.) 1 part by mass (solvent)
Propylene glycol monomethyl ether 50 parts by weight Methyl acetate 35 parts by weight

<Preparation of hard coat film 14>
A roll-shaped hard coat film 14 was produced in the same manner as the production of the hard coat film 2 except that the functional layer composition 101 of the functional layer 2 was changed to the following functional layer composition 104. The functional layer composition 104 was prepared as follows. That is, the fine particle was added to a solvent and dispersed with a Manton Gorin homogenizer, and then the following compound was added to the dispersion, followed by stirring and mixing to prepare the functional layer composition 104.

[Functional layer composition 104]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 95 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (fine particles)
Cross-linked polymethyl methacrylate particles (average particle size 5 μm, trade name: MBX-5, manufactured by Sekisui Plastics Co., Ltd.) 10 parts by mass (additive)
BYK-UV3510 (polyether-modified silicone, manufactured by Big Chemie Japan Co., Ltd.) 1 part by mass (solvent)
Propylene glycol monomethyl ether 50 parts by weight Methyl acetate 35 parts by weight

<Durability test>
The produced roll-shaped hard coat films 13 and 14 and the aforementioned roll-shaped hard coat film 2 were each wrapped in an aluminum moisture-proof sheet and stored for 40 days in a thermostatic bath at 60 ° C. and 80% relative humidity assuming long-term transportation. After storage for 40 days, the production of the polarizing plate, the hard coat film and the image display device were evaluated in the same manner as described above. The evaluation results are shown in Table 2.

  When the hard coat film is subjected to an endurance test under more severe conditions and then used in a liquid crystal display device, when the surface unevenness height (arithmetic mean roughness Ra) of the functional layer 2 is 10 nm or more ( It can be seen that the display unevenness due to the distortion of the film is suppressed and the visibility deterioration due to the deterioration of the flatness of the film is suppressed, and particularly excellent visibility is exhibited.

<Preparation of cellulose ester film 2>
(Preparation of polyester A)
In a nitrogen atmosphere, 4.85 g of dimethyl terephthalate, 4.4 g of 1,2-propylene glycol, 6.8 g of p-toluic acid, and 10 mg of tetraisopropyl titanate were mixed and stirred at 140 ° C. for 2 hours. Stirring was carried out at ° C for 16 hours. Next, the temperature was lowered to 170 ° C., and unreacted 1,2-propylene glycol was distilled off under reduced pressure to obtain polyester A.
Acid value: 0.1
Number average molecular weight: 490
Dispersity: 1.4
Component content of molecular weight 300-1800: 90%
Hydroxyl (hydroxyl) value: 0.1
Hydroxyl content: 0.04%

(Fine particle dispersion 1)
Fine particles (Aerosil R812 manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin to prepare a fine particle dispersion 1.

(Fine particle addition liquid 1)
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1

(Preparation of dope solution)
A dope solution having the following composition was prepared as follows. Methylene chloride and ethanol were added to the dissolution tank. Cellulose ester, sugar ester compound, polyester A, TINUVIN 928, and fine particle additive solution 1 were charged into a pressure dissolution tank containing a solvent while stirring. This was completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester (cellulose acetate propionate: acetyl group substitution degree 1.5, propionyl group substitution degree 0.9, total substitution degree 2.4, Mn 80000) 100 parts by mass Sugar ester compound ( Y-22) 7.0 parts by mass Polyester A 2.5 parts by mass TINUVIN 928 (manufactured by BASF Japan Ltd.) 1.5 parts by mass Fine particle additive 1 1.0 part by mass

(Film formation of cellulose ester film 2)
Next, an endless belt casting apparatus was used to uniformly cast the dope solution on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film was 75% by mass, and then peeled off from the stainless steel belt support with a peeling tension of 110 N / m.

  The peeled cellulose ester film was stretched 5% in the width direction using a tenter while applying heat at 160 ° C. At that time, the preheating temperature was given in advance so as to have different distributions in the width direction of the film, so that the residual solvent amount at the start of stretching had different distributions in the width direction. The amount of residual solvent at the start of stretching was 15% by mass at one end and 10% by mass at the other end.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. A roll-shaped cellulose ester film 2 having a film thickness of 75 μm, a width of 2000 mm, and a length of 5200 m was obtained by applying a knurling process having a width of 10 mm and a height of 5 μm to both ends of the film. In-plane retardation was measured by the above-described method. As a result, Ro was 10 nm, Ro variation was 1 nm, and Rt was 120 nm.

<Preparation of diagonally stretched film 1>
The cellulose ester film 2 was set in a slidable feeding device (film feeding portion) of the device of FIG. 6 and supplied to an oblique stretching machine in which a rail pattern was set so that the angle θi = 47 °. At that time, the distance between the main shaft of the guide roll closest to the inlet of the oblique stretching apparatus and the gripping tool (clip gripping part) of the oblique stretching apparatus was 30 cm. A clip having a length in the conveying direction of 1 inch (1 inch is 2.54 cm) and a guide roll having a diameter of 5 cm were used.

  Diagonal stretching was performed at a stretching temperature of 175 ° C. and a stretching ratio of 1.5 times with an oblique stretching tenter, and stretching was performed in an oblique direction so that the take-up tension at the tenter outlet was 200 N / m and the orientation angle θ was 45 °. The stretched film was controlled so that the fluctuation of the take-up tension was less than 3% by performing feedback control in which the change in the tension measured with the first roll on the outlet side of the obliquely stretched tenter was reflected in the take-up motor rotation speed. Then, after trimming both ends of the film, change the transport direction with a transport direction change device consisting of an air flow roll, apply a knurling process with a width of 10 mm and a height of 5 μm to both ends of the film, and wind it with a slidable winder, An obliquely stretched film 1 having a thickness of 50 μm, a width of 2000 mm, and a length of 5200 m was obtained. The obtained obliquely stretched film 1 had an in-plane retardation (Ro) of 135 nm, a thickness direction retardation Rt of 140 nm, and an orientation angle (θ) of 45 °.

  The film moving speed during heating and stretching was 20 m / min. The temperature of the preheating zone was 175 ° C., and the temperature of the cooling zone was 160 ° C. When the film was heated and stretched, the so-called “Boeing phenomenon” was eliminated, and stretching was performed with an optimum rail pattern so that the orientation angle was 45 °.

<Preparation of hard coat film 15>
A roll-shaped hard coat film 15 was produced in the same manner as the production of the hard coat film 2 except that the film substrate (cellulose ester film 1) was changed to the obliquely stretched film 1 described above. A durability test was performed on the obtained roll-shaped hard coat film 15 in the same manner as described above, and then an alkali treatment was performed to prepare a polarizing plate 115.

<Production of liquid crystal display device>
Next, the pre-bonded front plate of the Sony 60-type display BRAVIA LX900 and the polarizing plate on the front side of the panel are peeled off, and the prepared polarizing plate 113 and the polarizing plate 102 described above are respectively liquid crystal cells with an optical adhesive. The glass surface was pasted. In that case, it bonded so that an absorption axis might turn to the same direction as the polarizing plate previously bonded. Thereafter, the hard coat film and the liquid crystal display device were evaluated in the same manner as described above. Furthermore, crosstalk was also evaluated under the following conditions.

<Crosstalk evaluation>
The backlight of the produced liquid crystal display device was turned on, and the display image was observed without wearing the polarized sunglasses and tilting the neck, and then the image was observed by tilting the neck so that the polarized sunglasses tilted by 85 °. And the brightness | luminance fall (crosstalk) of the image | video observed before and after tilting a neck was evaluated based on the following references | standards.
(Evaluation criteria)
A: There is no crosstalk.
○: Very weak crosstalk appears.
Δ: Slight crosstalk appears.
X: Crosstalk clearly appears.

  The evaluation results of the liquid crystal display device are shown in Table 3.

  From Table 3, by using an obliquely stretched film (λ / 4 film) as the film substrate, it is possible to suppress display unevenness due to film distortion and visibility deterioration due to flatness deterioration, It can be seen that a liquid crystal display device having excellent crosstalk characteristics when wearing sunglasses can be realized.

  The optical film of the present invention can be used for image display devices such as polarizing plates and liquid crystal display devices.

1 Image display device 4 Liquid crystal cell (display cell)
5 Polarizing plate 11 Polarizer 12 Optical film (protective film, hard coat film)
21 Film substrate (λ / 4 film)
22 First functional layer (hard coat layer)
22a Hard coat layer 22b Hard coat layer 23 Second functional layer

Claims (9)

A film base and a first functional layer formed on one surface of the film base;
The first functional layer includes a hard coat layer,
The following value A obtained by an indentation depth setting load-unloading test in which a test force is applied to the surface of the hard coat layer by a microhardness meter and pushed to a set depth and then unloaded is 0. 0.02 to 0.90,
A = (h1-h2) / hmax
However,
h1: Residual depth (μm) when measured with an unloading retention time of 0 seconds
h2: Residual depth (μm) when measured with an unloading holding time of 60 seconds
hmax: Setting push-in depth (μm)
And the hard coat film characterized by satisfying at least one of the following conditions (1) and (2).
(1) The arithmetic average roughness Ra of the surface of the first functional layer is 2 nm or more.
(2) It has a 2nd functional layer in the other side of the film base material, and arithmetic mean roughness Ra of the surface of the 2nd functional layer is 2 nm or more.   The hard coat film according to claim 1, wherein the hard coat film has the second functional layer.   The hard coat film according to claim 1, wherein the value A is 0.20 or more and 0.90 or less.   The hard coat film according to any one of claims 1 to 3, wherein an arithmetic average roughness Ra of the surface of the first functional layer or the second functional layer is 10 nm or more.   5. The hard coat film according to claim 1, wherein the other surface of the film base or the second functional layer has a water contact angle of 95 ° or less.   The hard coat film according to claim 1, wherein the film substrate is a λ / 4 film.   The hard coat film according to any one of claims 1 to 6, wherein the film base has a thickness of 1 µm or more and less than 30 µm. Having a polarizer and a protective film formed on one surface of the polarizer;
The said protective film is a hard coat film in any one of Claim 1 to 7, The polarizing plate characterized by the above-mentioned. A display cell;
An image display device comprising: the polarizing plate according to claim 8 disposed on a viewing side of the display cell.

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