JP2020093534A - Laminate and manufacturing method thereof - Google Patents

Abstract

To provide a technique of preventing a flaw on a surface of a guide roll from being transferred onto a polyimide film surface through a substrate.SOLUTION: A laminate includes: a substrate having a first face and a second face; a first hard coat layer formed on the first face of the substrate; a transparent resin film layer laminated in a peelable manner on the first hard coat layer; and a second hard coat layer formed on the second face at an opposite side of the first side of the substrate, and a manufacturing method for the laminate is also provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate and a method for producing the same, and particularly to a laminate used for producing a highly visible transparent polyimide film and a method for producing the same.

In recent years, with the thinning, weight reduction, and flexibility of displays of various image display devices, transparent resin films based on polymers such as polyimide and polyamide have been widely used as a material replacing the conventionally used glass. .. A casting method (solution spraying method) is known as one of the methods for producing such a transparent resin film. In the casting method, in general, a varnish containing a polymer such as polyimide dissolved in a solvent is applied onto a support to form a film, and after removing the supporting base material, the solvent is removed by drying, thereby forming a resin film. Can be continuously molded (for example, Patent Document 1).

In addition, when a transparent polyimide film is obtained, a metal support such as SUS that is premised on reuse may be used, but from the viewpoint of quality control and cost of the support, a resin film premised on being disposable. A support consisting of is sometimes used.

JP, 10-310639, A

In an actual cast film forming apparatus, when applying a varnish containing a polyimide-based polymer on a support made of a resin film, the support is unwound from a support roll wound with a support, and several guide rolls are used. After passing, it moves to the varnish coating site. However, most of the guide rolls are made of metal, and some of them have scratches on the surface when the guide rolls are manufactured. In addition, the surface of the guide roll may be damaged during cleaning of the film forming apparatus or during operation of the film forming apparatus. When the surface of the guide roll has a flaw, the flaw may be transferred to the surface of the support and then transferred to the polyimide film formed in the varnish coating step. Naturally, in a polyimide film used for an image display device or the like, scratches and the like on the surface cause deterioration of visibility and deterioration of quality, and therefore must be avoided.

The support is coated with the varnish from a support roll through some guide rolls, and contacts not only the varnish-coated surface but also the back surface of the varnish. Also migrates to the back of the support. When it is wound into a roll again after it is coated, it will come into contact with the coated polyimide film, and in that case the scratches on the surface of the guide roll will also pass through the support to the polyimide system. It may be transferred to the film surface, but this must also be prevented.

Therefore, the present inventors have found a technique for preventing scratches on the surface of the guide roll from being transferred to the surface of the polyimide film via the support.

That is, the present invention includes the following aspects.
[1] A support having a first surface and a second surface, a first hard coat layer formed on the first surface of the support, and a releasable laminate on the first hard coat layer. And a second hard coat layer formed on the second surface of the support opposite to the first surface.
[2] The laminate according to [1], wherein the adhesion between the first hard coat layer and the transparent resin film layer is 0.02 N/10 mm or more.
[3] The laminate according to [1] or [2], wherein the support is a resin film.
[4] The support is any one of a polyethylene terephthalate film having a hard coat layer on both sides, a cycloolefin film, an acrylic film, a polyethylene naphthalate film, a polypropylene film, and a triacetyl cellulose film [1] to [. 3] The laminate according to any one of the above.
[5] In the support, the surface of the first hard coat layer has an arithmetic average roughness (Ra) of 0.01 μm or less defined in JIS B 0601-2001, which is 0.01 μm or less. The laminate described.
[6] The support according to any one of [1] to [5], wherein the support has a maximum height (Rz) of 0.1 μm or less defined in JIS B 0601-2001 on the surface of the first hard coat layer. Stack of.
[7] The laminate according to any one of [1] to [6], wherein the transparent resin film is a polyimide film.
[8] The laminate according to any one of [1] to [7], wherein the transparent resin film is a polyimide film having a haze of 1% or less, a total light transmittance of 85% or more and a yellow index of 4 or less.
[9] A laminate film roll obtained by winding the laminate according to any one of [1] to [8].
[10] a) A resin varnish obtained by mixing and stirring a resin composition for forming a transparent resin film with a solvent, and having a first surface and a second surface and having the first surface and the second surface thereof. The step of applying to the surface of the first hard coat layer formed on the first surface of the support having the hard coat layer provided on both sides thereof; and b) removing the solvent by drying the applied resin varnish. And forming a transparent resin film layer on the first hard coat layer;
[1] The method for producing a laminate according to [1].
[11] A window film substrate obtained by further subjecting a transparent resin film obtained by peeling from the laminate according to any one of [1] to [8] to solvent drying treatment.
[12] A window film comprising a window hard coat layer on at least one surface of the window film substrate according to [11].
[13] An optical laminate including the window film according to [12], further including a polarizing plate on one surface of the window film.
[14] The optical laminate according to [13], further including a touch sensor on one surface of the window film.

In the present invention, a support having a first surface and a second surface, a first hard coat layer formed on the first surface of the support, and a releasable laminated layer on the first hard coat layer. If it is a laminated body composed of the transparent resin film layer formed on the surface of the guide and a second hard coat layer formed on the second surface of the support opposite to the first surface, scratches present on the surface of the guide roll. However, it was found that transfer to the transparent polyimide film via the surface of the support can be prevented. Since it can be carried out simply and easily by forming hard coat layers on both sides of the support, it is highly useful. In addition, since scratches on both sides of the transparent polyimide film can be prevented, diffuse reflection of light is reduced, and when the light is transmitted by a backlight or the like, the backlight power can be reduced.

In addition, when the support is a resin film, a deposit may come out from the film during the steps such as heating, but the deposit may cause stains on the transparent polyimide film. However, when the hard coat layer is provided on both sides of the support, leakage of the precipitates is prevented, and the polyimide film is not stained. There is also a case where the hard coat layer is provided on one side. In that case, the support may bend (curl) due to the difference in the coefficient of thermal expansion. Such curling can also be prevented.

FIG. 1 is a diagram schematically showing a cross section of the laminate of the present invention. FIG. 2 is a schematic diagram showing a coating process of a transparent resin film. FIG. 3 is a photograph showing a state in which scratches on the roll surface are transferred to the transparent resin film.

FIG. 1 is a diagram schematically showing the laminate of the present invention, in which 1 indicates a support, 2 and 4 indicate a hard coat layer, and 3 indicates a transparent resin film. In FIG. 1, those having the support 1 and the hard coat layers 2 and 4 are represented by A, and those having the transparent resin film layer 3 on A are represented by B. The transparent resin film 3 is applied in the transparent resin film applying step 12 shown in FIG. The support roll 10 shown in FIG. 2 is a roll formed by winding the support 1 (denoted as A in FIG. 2) having the hard coat layers 2 and 4 on the front and back sides, and via the guide roll 11, It is sent to the coating process 12. Although three guide rolls 11 are shown in FIG. 2, the guide rolls 11 are actually sent to the coating step 12 through a number of guide rolls. Each guide roll is subjected to some processing or tension. In the coating step 12, the transparent resin film varnish is coated on the support A. In FIG. 2, the product coated with the transparent resin film is indicated as B. After the transparent resin film is applied, it is dried in the pre-drying step 13. In the pre-drying step 13, the transparent resin film 3 is dried to the extent that the transparent resin film 3 maintains its film shape in order to peel it from the support. At the time of obtaining, a main drying step of suppressing shrinkage of the transparent resin film in the width direction by a transverse stretching machine or drying while stretching in the width direction is necessary, but the step is not shown in FIG. A protective film unwound from the protective film roll 14 is formed on the surface of the pre-dried transparent resin film 3 opposite to the support 1 (having the hard coat layers 2 and 4 on both surfaces) to form a 5-layer winding roll 15. To form. The support 1 and the protective film are peeled off in a separate step using the three-layer winding roll 15 to form only the transparent resin film 3 and subjected to the main drying step to produce a transparent resin film from which the solvent is sufficiently removed. ..

Support As shown in FIG. 1, the laminate of the present invention includes a support 1 having a first surface and a second surface, a first hard coat layer 2 formed on the first surface of the support, A transparent resin film layer 3 releasably laminated on the first hard coat layer 2, and a second hard coat layer 4 formed on a second surface of the support opposite to the first surface. ,. The support is a sheet-like film having wide surfaces on the top and bottom (or the front and back), one surface is called the first surface, and the surface opposite to the first surface is called the second surface. The support of the present invention has a hard coat layer on both the first surface and the second surface.

The support of the present invention has a hard coat layer formed on both sides as described above. Preferred supports include polyethylene terephthalate (PET) film, cycloolefin film (COP), acrylic film, polyethylene naphthalate film, polypropylene film, triacetyl cellulose film, and more preferred supports include PET film. , A cycloolefin film, and the most preferable support is a PET film.

The hard coat layers formed on both sides of the support of the present invention are not particularly limited, and may be any of acrylic type, urethane type and epoxy type. In the present invention, the hard coat layer is formed on both surfaces (first surface and second surface), but even if the hard coat layers on both surfaces are the same, the first surface (transparent resin film The first hard coat layer on the layer side) and the second hard coat layer on the second surface opposite to the first surface may be different. When the first hard coat layer and the second hard coat layer are different, each can have a different function. It is easier to manufacture when the hard coat layers on both sides are the same.

When a hard coat layer is formed on both sides of a resin film as a support, it can be formed by a method of coating the composition for hard coat on one side of the resin film and curing the composition. Examples of the hard coat composition include a composition containing a photocurable (meth)acrylate monomer or oligomer, a polymerization initiator, and usually a solvent. A photopolymerization initiator is usually used as the polymerization initiator, and curing is performed by irradiating with ultraviolet rays.

When a support having a hard coat layer formed on both sides of a resin film is used as the support, the difference in contact angle with water can be adjusted by the curing conditions for forming the hard coat layer. However, the formation of the hard coat layer or the use of a composition containing a large amount of a polymerization initiator as the composition for forming the hard coat layer can reduce the difference in contact angle with water. It can also be adjusted by washing after forming the hard coat layer, and by washing with an organic solvent after forming the hard coat layer, the difference in contact angle with water can be reduced.

In the support, the contact angle with water of the laminated surface with the transparent resin film (that is, the surface of the first hard coat layer) was A, and the laminated surface was washed with γ-butyrolactone, dried, and then measured. Letting the contact angle with water be B, it is necessary that |B−A| is 8.0° or less. When the water contact angles A and B are controlled as described above, clouding of the transparent resin film can be prevented. The difference in contact angle with water before and after washing the surface of the support with γ-butyrolactone, ie, the value of |BA| is preferably 0 to 3.5°, more preferably 0 to 3.0°, and further preferably It is 0 to 2.0°, particularly preferably 0 to 1.0°. When the value of |BA| is larger than 8.0°, the clouding phenomenon often occurs on the surface of the transparent resin film.

Here, the term "white turbidity" refers to a level of white turbidity that is visible when the transparent resin film obtained after peeling from the support is observed with a high-intensity lamp of 3,000 lumens or more. In the peeled film, a part of the surface on the support side was washed with a clean room waste cloth, and then the appearance of the film was evaluated according to the white turbidity evaluation criteria described in Examples using a high-intensity light having a luminous flux of 3,000 lumens or more. It can be confirmed by visually evaluating (white turbidity).

When the resin varnish is applied to the support, the contact angle of water on the surface of the first hard coat layer of the support (on the side where the resin varnish is applied) is preferably 50 to 120°, more preferably 60 to 110°. , And more preferably 70 to 100°. When the contact angle of water on the surface of the first hard coat layer of the support is within the above range, the end of the applied resin varnish does not spread thinly, and the end of the resin film is peeled from the support to form a film. By increasing the amount of dust generated on one side, it tends to be less likely to cause process contamination, and also the contact angle of the resin film surface obtained by peeling from the support tends not to be high, so that the resin film can be processed in a later step. When performing a surface treatment such as hard coat coating, there is less risk of defects such as coating defects.

The contact angle with water is to measure the angle at which a water drop contacts the surface in order to evaluate the hydrophilicity (or hydrophobicity) of the surface of the object, and in the present invention, the Kyowa Interface Chemistry is used. The contact angle meter DM500 manufactured by Co., Ltd. is used in the θ/2 method using ultrapure water. A more detailed measuring method will be described in Examples. Further, the contact angle B against water is determined by washing γ-butyrolactone with a clean room waste cloth impregnated with γ-butyrolactone after a certain time has passed after dropping γ-butyrolactone on the surface of the support on which the transparent resin film is laminated. Further, after drying the γ-butyrolactone remaining on the surface, it is obtained by dropping water and measuring the contact angle with water in the same manner. The hydrophilicity (or hydrophobicity) after washing the surface with γ-butyrolactone is obtained. Sex) is evaluated. A more detailed measuring method of the contact angle B against water will be described in Examples. In order to reduce the influence of measurement error, the contact angle with water is measured 10 times or more, and the average value is set to A or B.

The support having the double-sided hard coat layer useful in the present invention can be used as a commercially available product. For example, a hard coat film marketed under the name of Tough Top (registered trademark) by Toray Co., Ltd., a hard coat film marketed under the name of KB Film (registered trademark) by Kimoto Co., Ltd., and Toyo Cross ( Hard coat film and the like which are commercially available under the name of Toro (registered trademark) HC film.

The support preferably has a Martens hardness of 300 N/mm or more on the side in contact with the transparent resin film 2 (that is, the first hard coat layer). The Martens hardness of the second hard coat layer on the surface of the support opposite to the first hard coat layer may be the same as or different from the Martens hardness of the first hard coat layer, but is about the same. preferable.

The Martens hardness was obtained by laminating a sample of a predetermined size on glass, and using an ultra-fine hardness tester (FISCHERSCOPE HM2000: manufactured by Fisher Instruments Co., Ltd.) in an atmosphere of 23° C. and 55% RH using Vickers. It is a value measured by applying a load at a pressurizing rate of 0.5 mN/5 seconds using an indenter and then holding for 5 seconds while maintaining a load of 0.5 mN. The detailed Martens hardness measurement method is described in Examples.

In the present invention, the Martens hardness is preferably 300 N/mm or more, more preferably 350 N/mm or more, further preferably 380 N/mm or more, and particularly preferably 400 N/mm or more. The upper limit of the Martens hardness is not particularly limited, but in the case of a support provided with a hard coat layer, if the Martens hardness is too high, the hard coat layer may be cracked during transportation, and usually 700 N/mm or less. It is preferably 650 N/mm or less, more preferably 600 N/mm or less. When the Martens hardness of the side of the support that contacts the transparent resin film (that is, the first hard coat layer) is 300 N/mm or more, scratches existing on a roll such as a guide roll are transferred to the support. However, scratches are less likely to occur such that they are transferred to the transparent resin film formed thereafter. An example thereof is shown in FIG. In the present specification, the scratch of the transparent resin film means that the transparent resin film peeled from the support is irradiated with a high-intensity lamp of 3,000 lumens or more to visually check for scratches, and it can be confirmed that there are scratches. Means when. Generally, films for optical use are often evaluated for appearance quality such as scratches under fluorescent lamps, but on the viewing side of image display devices, especially when used as a front plate (window film), appearance quality requirements are required. It is also necessary to suppress scratches that have a high level and cannot be visually recognized under a fluorescent lamp. In the case of a high-intensity lamp of 3,000 lumens or more, it is possible to evaluate not only scratches visually recognized under a fluorescent lamp but also the presence or absence of scratches with weaker visibility.

The support of the present invention preferably has an arithmetic average roughness (Ra) on the surface (the side in contact with the transparent resin film (that is, the first hard coat layer)) within a predetermined range. The arithmetic mean roughness (Ra) is measured using a contact type roughness meter and conforms to JIS B 0601-2001. The surface of the support has an arithmetic average roughness (Ra) of 0.01 μm or less, preferably 0.008 μm or less, and more preferably 0.006 μm or less. Since the shape of the side in contact with the transparent resin film, that is, the surface is transferred to the surface of the transparent resin film, the smaller the arithmetic average roughness (Ra) of the surface of the support, the easier the glossiness of the transparent resin film can be obtained. Therefore, it is suitable when it is arranged in the image display device. The lower limit of the arithmetic average roughness (Ra) of the surface of the support is not particularly limited, and the smaller the better.

The maximum height (Rz) of the surface of the support of the present invention is preferably within a predetermined range. The maximum height (Rz) is measured using a contact type roughness meter and conforms to JIS B 0601-2001. The maximum height (Rz) of the surface of the support is 0.1 μm or less, preferably 0.08 μm or less, and more preferably 0.05 μm or less. Since the shape of the side in contact with the transparent resin film (that is, the first hard coat layer) is transferred to the surface of the transparent resin film, when the maximum height (Rz) of the surface of the support is large, the transparent resin film The height of local unevenness on the surface of the is also large and the surface tends to be rough. Therefore, the smaller the maximum height (Rz) of the surface of the support (that is, the first hard coat layer) is, the better, and it is particularly suitable when it is arranged in the image display device. The lower limit of the maximum height (Rz) of the surface of the support is not particularly limited, and the smaller the better.

The arithmetic mean roughness (Ra) and the maximum height (Rz) of the surface of the second hard coat layer (the side not in contact with the transparent resin film) of the support are the same as those of the first hard coat layer. Although they may be different, it is preferable that they are the same.

Transparent Resin Film The transparent resin film constituting the laminate of the present invention is composed of a resin composition containing at least one selected from the group consisting of polyimide, polyamide and polyamideimide.

In the present specification, polyimide represents a polymer containing a repeating structural unit containing an imide group, and polyamideimide is a polymer containing both a repeating structural unit containing an imide group and a repeating structural unit containing an amide group. And polyamide means a polymer containing repeating structural units containing an amide group. The polyimide-based polymer represents a polymer containing at least one selected from polyimide and polyamide-imide.

The polyimide-based polymer according to this embodiment has a repeating structural unit represented by the formula (10). Here, G represents a tetravalent organic group, and A represents a divalent organic group. G and/or A may include two or more different types of repeating structural units represented by formula (10). In addition, the polyimide-based polymer according to the present embodiment is a repeating polymer represented by any one of formula (11), formula (12), and formula (13) as long as it does not impair various physical properties of the obtained transparent resin film. It may include any one or more of the structural units.

It is preferable from the viewpoint of strength and transparency of the transparent resin film that the main structural unit of the polyimide-based polymer is a repeating structural unit represented by the formula (10). In the polyimide-based polymer according to the present embodiment, the constitutional ratio of the repeating structural unit represented by the formula (10) is preferably 40 mol% or more, more preferably 50% by mole, based on all the repeating structural units of the polyimide-based polymer. It is at least mol%, more preferably at least 70 mol%, particularly preferably at least 90 mol%, and even more preferably at least 98 mol%. The constitutional ratio of the repeating structural unit represented by formula (10) may be 100 mol %.

G and G ¹ each independently represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, in which case the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. As G and G ¹ , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) Or a group represented by the formula (29) and a chain hydrocarbon group having 4 or less carbon atoms and having 6 or less carbon atoms. In the formula * represents a bond, Z is a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH3) -, - C (CH 3) 2 -, - _{C (CF 3) 2 -,} - Ar -, - SO 2 -, - CO -, - O-Ar-O -, - Ar-O-Ar -, - Ar-CH 2 -Ar -, - Ar-C _{(CH 3)} represents a 2 -Ar-, or _-Ar-SO 2 -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms which may be substituted with a fluorine atom, and a specific example thereof is a phenylene group. Since it is easy to suppress the yellowness of the obtained transparent resin film, it is preferable that G and G ¹ are formula (20), formula (21), formula (22), formula (23), formula (24), formula Examples include groups represented by (25), formula (26) or formula (27).

G ² represents a trivalent organic group, preferably a C 4-40 trivalent organic group. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, in which case the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. As G ² , the formula (20), the formula (21), the formula (22), the formula (23), the formula (24), the formula (25), the formula (26), the formula (27), the formula (28), or Examples thereof include a group in which any one of the bonds of the group represented by the formula (29) is replaced with a hydrogen atom, and a trivalent chain hydrocarbon group having 6 or less carbon atoms. The example of Z in the formula is the same as the example of Z in the description regarding G.

G ³ represents a divalent organic group, preferably a C 4-40 divalent organic group. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, in which case the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. As G ³ , the formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or Among the bonds of the group represented by the formula (29), a group in which two nonadjacent bonds are replaced by hydrogen atoms and a divalent chain hydrocarbon group having 6 or less carbon atoms are exemplified. The example of Z in the formula is the same as the example of Z in the description regarding G.

A, A ¹ , A ² and A ³ each represent a divalent organic group, preferably a C 4-40 divalent organic group. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms, in which case the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 to 8. A, A ¹ , A ² and A ³ are, respectively, formula (30), formula (31), formula (32), formula (33), formula (34), formula (35), formula (36), formula (37) or a group represented by the formula (38); a group in which these are substituted with one or more kinds of a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and a chain hydrocarbon group having 6 or less carbon atoms Is exemplified.

In the formula * represents a ^bond, Z 1, ^{Z 2} and ^{Z 3} are each independently a single _{bond, -O -, - CH 2 -} , - CH 2 -CH 2 -, - CH (CH 3 _{) -, - C (CH 3} ) 2 -, - C (CF 3) 2 -, - S -, - SO 2 -, - CO- or -N ^{(R 2)} - represents a. Here, R ² represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Z ¹ and Z ² , and Z ² and Z ³ , respectively, are preferably located in the meta or para position with respect to each ring.

In the present invention, the resin composition forming the transparent resin film may contain polyamide. The polyamide according to this embodiment is a polymer mainly composed of the repeating structural unit represented by the formula (13). The preferred examples and specific examples of G ³ and A ³ in the polyamide are the same as the preferred examples and specific examples of G ³ and A ³ in the polyimide-based polymer. The polyamide may include two or more kinds of repeating structural units represented by the formula (13) having different G ³ and/or A ³ .

The polyimide-based polymer can be obtained, for example, by polycondensation of a diamine and a tetracarboxylic acid compound (tetracarboxylic dianhydride, etc.), for example, JP 2006-199945 A or JP 2008-163107 A. Can be synthesized according to the method described in. Examples of commercially available polyimides include Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Inc. and KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd.

Examples of the tetracarboxylic acid compound used in the synthesis of the polyimide-based polymer include aromatic tetracarboxylic acid and its anhydride, preferably aromatic tetracarboxylic acid compound such as its dianhydride; and aliphatic tetracarboxylic acid and its anhydride. And preferably aliphatic carboxylic acid compounds such as dianhydrides thereof. The tetracarboxylic acid compound may be a tetracarboxylic acid compound derivative such as a tetracarboxylic acid chloride compound in addition to the anhydride, and these may be used alone or in combination of two or more kinds.

Specific examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydride, monocyclic aromatic tetracarboxylic dianhydride and condensed polycyclic aromatic tetracarboxylic dianhydride. Examples thereof include carboxylic acid dianhydride. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include 4,4′-oxydiphthalic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride and 2,2′. ,3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxy) Phenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic acid dianhydride (may be described as 6FDA. Yes, 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4) -Dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3- Examples include dicarboxyphenyl)methane dianhydride, 4,4′-(p-phenylenedioxy)diphthalic acid dianhydride, and 4,4′-(m-phenylenedioxy)diphthalic acid dianhydride. The monocyclic aromatic tetracarboxylic dianhydride is 1,2,4,5-benzenetetracarboxylic dianhydride, and the condensed polycyclic aromatic tetracarboxylic dianhydride is 2,3,6,7-naphthalene tetracarboxylic dianhydride can be mentioned.

Among these, 4,4'-oxydiphthalic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and 2,2',3,3'-benzophenone tetracarboxylic acid dianhydride are preferable. Anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl Sulfonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2- Bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl) Ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3 ,4-Dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p- Examples thereof include phenylenedioxy)diphthalic acid dianhydride and 4,4′-(m-phenylenedioxy)diphthalic acid dianhydride, and more preferably 4,4′-oxydiphthalic acid dianhydride, 3,3′, 4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) , Bis(3,4-dicarboxyphenyl)methane dianhydride and 4,4′-(p-phenylenedioxy)diphthalic acid dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic acid dianhydride include cyclic or acyclic aliphatic tetracarboxylic acid dianhydride. The cycloaliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride. , 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, etc., cycloalkanetetracarboxylic dianhydride, bicyclo[2.2 .2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl 3,3′-4,4′-tetracarboxylic dianhydride and positional isomers thereof. .. These can be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic acid dianhydride and 1,2,3,4-pentanetetracarboxylic acid dianhydride. These may be used alone or in combination of two or more. Moreover, you may use combining cycloaliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride.

Among the tetracarboxylic acid compounds, the alicyclic tetracarboxylic dianhydride or the non-condensed polycyclic aromatic tetra is preferable from the viewpoint of easily improving the elastic modulus of the transparent resin film, bending resistance, and optical properties. Examples thereof include carboxylic acid dianhydride. More preferred specific examples include 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis(3 , 4-dicarboxyphenyl)propane dianhydride and 4,4′-(hexafluoroisopropylidene)diphthalic acid dianhydride (6FDA). These can be used alone or in combination of two or more.

Polyimide-based polymer according to the present embodiment, in the range that does not impair various physical properties of the resulting transparent resin film, in addition to the anhydride of tetracarboxylic acid used in the above polyimide synthesis, tetracarboxylic acid, tricarboxylic acid compound, It may be a compound obtained by further reacting a dicarboxylic acid compound, an anhydride thereof and a derivative thereof.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids and their related acid chloride compounds, acid anhydrides, and the like, and two or more kinds thereof may be used in combination. Specific examples thereof include 1,3,5-benzenetricarboxylic acid and 1,2,4-benzenetricarboxylic acid anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and the acid is a single _{bond, -CH 2 -, - C (} CH 3) 2 -, - C (CF 3) 2 -, - SO 2 - , or compounds linked phenylene group.

Examples of the dicarboxylic acid compound include aromatic dicarboxylic acids, aliphatic dicarboxylic acids and their related acid chloride compounds, acid anhydrides, and the like, and two or more kinds thereof may be used in combination. Specific examples thereof include terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4′-biphenyldicarboxylic acid; 3,3′-biphenyldicarboxylic acid; a chain hydrocarbon having 8 or less carbon atoms; two benzoate skeleton _{-CH 2 -, - S -,} - C (CH 3) 2 -, - C (CF 3) 2 -, - O -, - N (R 9) -, - C (= O ) _-, - SO 2 -, or compounds linked phenylene group. These can be used alone or in combination of two or more. Here, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom.

The dicarboxylic acid compound is preferably terephthalic acid; isophthalic acid; 4,4′-biphenyldicarboxylic acid; 3,3′-biphenyldicarboxylic acid; and the two benzoic acid skeletons are —CH 2 —, —C(═O)—. ^{, -O -, - N (R} 9) -, - SO 2 - or a compound linked phenylene groups, more preferably, terephthalic acid, 4,4'-biphenyl dicarboxylic acid; and two benzoic acid skeleton There ^{-O -, - N (R 9} ) -, - compounds linked by - C (= O) - or -SO _2. These can be used alone or in combination of two or more.

The ratio of the tetracarboxylic acid compound to the total of the tetracarboxylic acid compound, the tricarboxylic acid compound, and the dicarboxylic acid compound is preferably 40 mol% or more, more preferably 50 mol% or more, further preferably 70 mol% or more, and further It is preferably 90 mol% or more, and particularly preferably 98 mol% or more.

Examples of the diamine used for synthesizing the polyimide-based polymer include aliphatic diamine, aromatic diamine, and a mixture thereof. In addition, in this embodiment, an "aromatic diamine" represents the diamine in which the amino group is directly couple|bonded with the aromatic ring, and the aliphatic group or other substituents may be included in a part of the structure. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring and a fluorene ring, but are not limited thereto. Among these, a benzene ring is preferable. The "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and an aromatic ring or other substituent may be included in a part of its structure.

Specific examples of the aliphatic diamines include acyclic aliphatic diamines such as hexamethylenediamine and 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, 4,4′. Examples thereof include cycloaliphatic diamines such as diaminodicyclohexylmethane, and these can be used alone or in combination of two or more kinds.

Specific examples of the aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene and 2,6-diamino. Aromatic diamine having one aromatic ring such as naphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3 '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis (4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)) Phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl( Sometimes described as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl) ) Aromatic diamines having two or more aromatic rings, such as fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, and 9,9-bis(4-amino-3-fluorophenyl)fluorene. Be done. These can be used alone or in combination of two or more.

The aromatic diamine is preferably 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2′-dimethylbenzidine, 2,2′-bis (Trifluoromethyl)-4,4′-diaminodiphenyl (TFMB) and 4,4′-bis(4-aminophenoxy)biphenyl, more preferably 4,4′-diaminodiphenylmethane and 4,4′-diamino. Diphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2 -Bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB), 4,4' -Bis(4-aminophenoxy)biphenyl. These can be used alone or in combination of two or more.

The diamine may have a fluorine-based substituent. Examples of the fluorine-based substituent include a perfluoroalkyl group having 1 to 5 carbon atoms such as a trifluoromethyl group, and a fluoro group.

Among the above diamines, from the viewpoints of high transparency and low coloring property, it is preferable to use at least one selected from the group consisting of aromatic diamines having a biphenyl structure, and specific examples thereof include 2,2′-dimethylbenzidine. , 2,2′-bis(trifluoromethyl)-4,4′-diaminodiphenyl (TFMB) and 4,4′-bis(4-aminophenoxy)biphenyl may be used. preferable. A diamine having a biphenyl structure and a fluorine-containing substituent is more preferable, and as a specific example, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB) is more preferable.

The polyimide-based polymer is represented by the formula (10), which is formed by polycondensation of a diamine and a tetracarboxylic acid compound (including a tetracarboxylic acid compound derivative such as an acid chloride compound and tetracarboxylic acid dianhydride). It is a condensation type polymer containing a repeating structural unit. In addition to these, tricarboxylic acid compounds (including tricarboxylic acid compound derivatives such as acid chloride compounds and tricarboxylic acid anhydrides) and dicarboxylic acid compounds (including derivatives such as acid chloride compounds) can also be used as starting materials. is there. Polyamide is a condensation-type polymer containing a repeating structural unit represented by the formula (13), which is formed by polycondensation of a diamine and a dicarboxylic acid compound (including a derivative such as an acid chloride compound).

The repeating structural units represented by formulas (10) and (11) are usually derived from diamines and tetracarboxylic acid compounds. The repeating structural unit represented by formula (12) is usually derived from a diamine and a tricarboxylic acid compound. The repeating structural unit represented by formula (13) is usually derived from a diamine and a dicarboxylic acid compound. Specific examples of the diamine, the tetracarboxylic acid compound, the tricarboxylic acid compound and the dicarboxylic acid compound are as described above.

The molar ratio of the diamine and the carboxylic acid compound such as the tetracarboxylic acid compound can be appropriately adjusted within the range of 0.9 mol or more and 1.1 mol or less of the tetracarboxylic acid with respect to 1.00 mol of the diamine. Since it is preferable that the obtained polyimide-based polymer has a high molecular weight in order to exhibit high folding endurance, the amount of tetracarboxylic acid used relative to 1.00 mol of diamine is more preferably 0.98 mol or more and 1.02 mol, More preferably, it is 0.99 mol% or more and 1.01 mol% or less.

In addition, from the viewpoint of suppressing the yellowness of the obtained transparent resin film, it is preferable that the ratio of amino groups occupying the terminals of the obtained polymer is low, and carboxylic acid compounds such as tetracarboxylic acid compounds relative to 1.00 mol of diamine. The amount used is preferably 1.00 mol or more.

The amount of fluorine in the molecule of the diamine and the carboxylic acid compound (for example, tetracarboxylic acid compound) is adjusted, and the amount of fluorine in the obtained polyimide-based polymer is preferably 1 mass based on the mass of the polyimide-based polymer. % Or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and particularly preferably 20% by mass or more. Since the raw material cost tends to increase as the proportion of fluorine increases, the upper limit of the amount of fluorine is preferably 40% by mass or less. The fluorine-based substituent may be present in either the diamine or the carboxylic acid compound, or may be present in both. In particular, the inclusion of the fluorine-based substituent may reduce the YI value.

The polyimide-based polymer according to this embodiment may be a copolymer including a plurality of different types of repeating structural units described above. The weight average molecular weight of the polyimide-based polymer in terms of standard polystyrene is usually 100,000 to 800,000. The molecular weight of the polyimide-based polymer is preferably 200,000 or more, more preferably 300,000 or more, and further preferably because the flexibility of the film obtained when a film is formed using the polyimide-based polymer is improved. It is 350,000 or more. Further, since a varnish having an appropriate concentration and viscosity can be obtained and the film-forming property tends to be improved, the molecular weight is preferably 750,000 or less, more preferably 600,000 or less, and further preferably 500,000. It is below. Two or more kinds of polyimide polymers having different weight average molecular weights may be used in combination. Further, other polymer materials may be mixed as long as the physical properties are not impaired.

By containing a fluorine-containing substituent, the polyimide-based polymer and the polyamide show a tendency that the elastic modulus when formed into a film is improved and the YI value is reduced. When the elastic modulus of the film is high, generation of scratches and wrinkles tends to be suppressed. From the viewpoint of transparency of the film, the polyimide-based polymer and the polyamide preferably have a fluorine-containing substituent. Specific examples of the fluorine-containing substituent include a fluoro group and a trifluoromethyl group.

The content of fluorine atoms in the mixture of the polyimide-based polymer and the polyimide-based polymer and the polyamide, respectively, based on the total of the mass of the polyimide-based polymer or the mass of the polyimide-based polymer and the mass of the polyamide, preferably It is 1% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 40% by mass or less. When the content of fluorine atoms is within the above range, the YI value when formed into a film tends to be further reduced, and the transparency can be further improved. Also, when formed into a film, handling is likely due to generation of static electricity. At times, irregular bending is likely to occur, and it tends to be difficult to increase the molecular weight of the polyimide.

In the present invention, the content of the polyimide-based polymer and/or polyamide in the resin composition constituting the transparent resin film is preferably 40% by mass or more, more preferably 50% by mass, based on the solid content of the resin composition. As described above, the content is more preferably 60% by mass or more, further preferably 70% by mass or more, and may be 100% by mass. When the content of the polyimide-based polymer and/or polyamide is within the above range, the flexibility of the transparent resin film is good. The solid content refers to the total amount of components excluding the solvent from the resin composition.

In the present invention, the resin composition forming the transparent resin film may further contain an inorganic material such as inorganic particles in addition to the polyimide-based polymer and/or polyamide. Examples of the inorganic material include inorganic particles such as silica particles, titanium particles, aluminum hydroxide, zirconia particles, and barium titanate particles, and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate. From the viewpoint of the stability of the varnish and the dispersibility of the inorganic material, silica particles, aluminum hydroxide, zirconia particles are preferable, and silica particles are more preferable.

The average primary particle diameter of the inorganic material particles is preferably 1 to 200 nm, more preferably 3 to 100 nm, still more preferably 5 to 50 nm, even more preferably 5 to 30 nm. When the average primary particle diameter of the silica particles is within the above range, the transparency tends to be improved, and the cohesive force of the silica particles is weakened, so that the silica particles tend to be easily handled.

In the present invention, the silica particles may be silica sol in which silica particles are dispersed in an organic solvent or the like, or silica fine particle powder produced by a gas phase method, but a liquid phase is preferable because it is easy to handle. It is a silica sol produced by the method.

The average primary particle diameter of silica particles in the transparent resin film can be determined by observation with a transmission electron microscope (TEM). The particle size distribution of silica particles before forming the transparent resin film can be determined by a commercially available laser diffraction particle size distribution meter.

In the present invention, when the resin composition contains an inorganic material, the content of the inorganic material is preferably 1% by mass or more, more preferably 5% by mass or more, and further preferably, based on the solid content of the resin composition. 10 mass% or more, particularly preferably 20 mass% or more, preferably 60 mass% or less, more preferably 50 mass% or less, further preferably 45 mass% or less, particularly preferably 40 mass% or less, these It may be within a range in which the upper limit and the lower limit are combined. When the content of the filler is at least the above lower limit, the impact resistance of the optical film is likely to be improved, and when it is at most the above upper limit, the transparency and mechanical strength of the transparent resin film tend to be compatible with each other. The solid content refers to the total amount of components excluding the solvent from the resin composition.

The resin composition forming the transparent resin film may further contain other components in addition to the components described above. Other components include, for example, antioxidants, release agents, light stabilizers, bluing agents, flame retardants, lubricants and leveling agents.

In the present invention, when the resin composition contains a resin component such as a polyimide polymer and other components other than the inorganic material, the content of the other components is preferably 0.001% with respect to the total mass of the transparent resin film. Or more and 20 mass% or less, more preferably 0.002% or more and 10 mass% or less.

In the present invention, the transparent resin film is, for example, a reaction solution of a polyimide-based polymer and/or polyamide, which is obtained by reacting by selecting from the tetracarboxylic acid compound, the diamine and the other raw materials, and if necessary, It can be produced from a resin varnish prepared by adding a solvent to a resin composition containing an inorganic material and other components, and mixing and stirring. In the resin composition, instead of a reaction liquid such as a polyimide-based polymer, a purchased solution of a polyimide-based polymer or the like or a purchased solution of a solid polyimide-based polymer or the like may be used.

As the solvent that can be used for preparing the resin varnish, one that can dissolve or disperse the resin component such as the polyimide-based polymer can be appropriately selected. From the viewpoint of solubility, coating property and drying property of the resin component, the boiling point of the solvent is preferably 120 to 300°C, more preferably 120 to 270°C, further preferably 120 to 250°C, and particularly preferably 120 to It is 230°C. Specific examples of such a solvent include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; lactone solvents such as γ-butyrolactone and γ-valerolactone; Ketone solvents such as cyclohexanone, cyclopentanone and methyl ethyl ketone; Acetate ester solvents such as butyl acetate and amyl acetate; Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane; Carbonate solvents such as ethylene carbonate and propylene carbonate. Is mentioned. Among them, N,N-dimethylacetamide (boiling point: 165° C.), γ-butyrolactone (boiling point: 204° C.), N-methylpyrrolidone (boiling point: 202° C.), because of excellent solubility in polyimide-based polymers and polyamides, A solvent selected from the group consisting of butyl acetate (boiling point: 126° C.), cyclopentanone (boiling point: 131° C.) and amyl acetate (boiling point: 149° C.) is preferable. As the solvent, one type may be used alone, or two or more types may be used in combination. When two or more solvents are used, it is preferable to select the type of solvent so that the highest boiling point of the solvents used falls within the above range.

The amount of the solvent may be selected so that the viscosity allows the resin varnish to be handled, and is not particularly limited. For example, it is preferably 50 to 95% by mass, more preferably 70 to 95% with respect to the total amount of the resin varnish. It is mass %, more preferably 80 to 95 mass %.

The transparent resin film of the present invention is obtained by applying the resin varnish on a support and predrying. In the present specification, hard coat layers are present on both sides of the support, but the hard coat layer may be referred to as “support” without referring to it. The transparent resin film is releasably laminated on the support. Releasable means that the film can maintain its shape and can be peeled from the support without breaking. Specifically, it means drying by pre-drying so that an appropriate amount of solvent remains. Here, if the amount of residual solvent is too large, the shape of the film cannot be maintained, and if the amount of residual solvent is too small, the adhesiveness to the support becomes too high and the film is broken during peeling. The appropriate amount of residual solvent varies depending on the resin composition of the transparent resin film, the solvent, and the type of the hard coat layer on the surface of the support, and it is necessary to appropriately adjust. However, the content of the solvent in the transparent resin film is usually 0.1% by mass or more based on the total mass of the transparent resin film. The upper limit of the solvent content in the transparent resin film is not particularly limited as long as the shape of the transparent resin film can be maintained, but is usually 50% by mass or less based on the total mass of the transparent resin film. In addition, in this invention, the solvent content in a transparent resin film uses the thermogravimetry-differential heat (TG-DTA) measuring device, and the mass from 120 degreeC to 250 degreeC is described, for example in the below-mentioned Example. The reduction rate (mass %) can be measured and calculated.

In the present invention, the support and the resin film must be peelable from each other. However, if the adhesion is too weak and peels easily, another problem occurs. For example, in an actual film forming apparatus, the support may be peeled off at the bent portion when passing the guide roll during conveyance of the laminate. Therefore, it is preferable that the laminated body is not peeled off even if it is wound around a cylindrical rod having a diameter of 100 mm by 180°, and it is more preferable that the laminated body is not peeled off even when wound around a cylindrical rod having a diameter of 80 mm by 180°, It is more preferable that the laminated body is not peeled off even if it is wound around a cylindrical rod by 180°, and it is even more preferable that the laminated body is not peeled off even when it is wound around a cylindrical rod having a diameter of 40 mm by 180°. It is particularly preferable that the laminated body is not peeled off even when it is wound around the rod by 180°.

The thickness of the transparent resin film may be appropriately determined according to the application of the transparent resin film, etc., but is usually 10 to 500 μm, preferably 15 to 200 μm, and more preferably 20 to 130 μm. When the thickness of the transparent resin film is within the above range, the flexibility of the transparent resin film is good.

The tensile modulus of elasticity of the transparent resin film is usually 3.5 GPa or more, preferably 4.0 GPa or more. When the tensile elastic modulus of the window film base material is larger than 3.5 GPa, it can be preferably used from the viewpoint of bending resistance. The upper limit of the elastic modulus is usually 100 GPa or less.

In the laminate of the present invention, the transparent resin film preferably has a haze of 1.0% or less, a total light transmittance of 85% or more, and a yellow index (yellowness) of 3.0% or less. If such requirements are satisfied, it can be used as a good resin film having high transparency. The methods for measuring haze, total light transmittance and yellow index (yellowness) are described in detail in the examples. The haze is like cloudiness of the resin film, and the smaller the haze, the better, and is preferably 0.7% or less, more preferably 0.5% or less. The total light transmittance is the transmittance of light rays passing through the film, and transparency means that it is better to be close to 100%, preferably 85% or more, more preferably 87% or more, further preferably 89% or more. .. When the transmittance is within the above range, for example, bright display can be obtained without lowering the illuminance of the backlight, which can contribute to energy saving. Further, the yellow index is the degree of yellowness, and the smaller the degree of yellowness is, the better the performance is, and it is preferably 2.5% or less, more preferably 2.2% or less.

(Protective film)
The laminate of the present invention may include a protective film attached to the transparent resin film. The protective film is attached to the surface of the transparent resin film which is not the support side. When winding the laminate into a roll, if there is a problem with the winding property such as blocking, in addition to the above, a protective film is attached to the surface of the support opposite to the transparent resin film. Good. The protective film attached to the transparent resin film is a film for temporarily protecting the surface of the transparent resin film, and is not particularly limited as long as it is a peelable film capable of protecting the surface of the transparent resin film. Examples thereof include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyolefin resin films such as polyethylene and polypropylene films; acrylic resin films; polyolefin resin films, polyethylene terephthalate resin films and It is preferably selected from the group consisting of acrylic resin films. When protective films are attached to both surfaces of the laminate, the protective films on each surface may be the same as or different from each other.

The thickness of the protective film is not particularly limited, but is usually 10 to 100 μm, preferably 10 to 80 μm, and more preferably 10 to 50 μm. When the protective films are attached to both surfaces of the laminate, the thickness of the protective film on each surface may be the same or different.

(Laminate film roll)
In the present invention, a laminate film roll is formed by winding the laminate (a support having a double-sided hard coat layer, a transparent resin film and, if necessary, a protective film) around a winding core. In the continuous production, the laminated film roll is often stored once in the form of a film roll due to space and other restrictions, and the laminated film roll is one of them. In the form of the laminate film roll, since the laminate is tightly wound, scratches on the support are easily transferred onto the transparent resin film. However, when a support having a hard coat layer on both sides of the present invention is used, it is difficult for scratches to be transferred from a guide roll or the like to the support due to the function of the hard coat layer, and even when wound with a laminate film roll, scratches are generated. Unlikely to occur. Precipitates such as oligomers also bleed from the support due to heating, etc., but since there are hard coat layers on both sides of the support, the precipitates are not transferred onto the transparent resin film, so defects due to bleeding are also eliminated. ..

Examples of the material forming the core of the laminated film roll include polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyester resin, epoxy resin, phenol resin, melamine resin, silicon resin, polyurethane resin, polycarbonate resin, ABS resin, etc. And the like; a metal such as aluminum; a fiber reinforced plastic (FRP: a composite material in which fibers such as glass fibers are contained in a plastic to improve the strength). The winding core has a cylindrical shape or a cylindrical shape, and the diameter thereof is, for example, 80 to 170 mm. The diameter of the film roll (the diameter after winding) is not particularly limited, but is usually 200 to 800 mm.

The present invention also provides a method for producing the above laminate. The manufacturing method of the above-mentioned laminated body,
a) A resin varnish obtained by mixing and stirring a resin composition for forming a transparent resin film with a solvent, which has a first surface and a second surface and is on both the first surface and the second surface. A step of applying to the surface of the first hard coat layer formed on the first surface of the support having a hard coat layer formed thereon; and b) removing the solvent by drying the applied resin varnish and supporting Forming a layer of transparent resin film on the body;
including. When forming a protective film,
c) It is necessary to further include laminating a protective film on the surface of the transparent resin film formed on the supporting substrate on the side opposite to the supporting substrate.

The laminate of the present invention, by forming a hard coat layer on both surfaces of the support, the transparent resin film due to scratches on the surface of the guide roll or the like, particularly scratches of the transparent polyimide-based film are reduced. The yield is greatly improved and the productivity is improved. Further, since it is possible to prevent the occurrence of precipitates from the support, it is possible to suppress scratches on the support.

When the heat shrinkage of the laminate of the present invention is small, the deformation of the film during heat drying is small, and the transportability of the support and the thickness distribution of the transparent resin film are improved. The heat shrinkage rate in both MD and TD directions is preferably less than 1%, more preferably less than 0.8%, further preferably less than 0.6%. A film having a small TD heat shrinkage is more preferable.

(Window film base material)
The transparent resin film obtained by peeling the support from the laminate of the present invention is further dried to reduce the amount of residual solvent, so that it can be used as a window film base material. The main drying step is not particularly limited, but it is preferable to dry while fixing the width direction with a transverse stretching machine or the like in order to prevent deformation during drying. When the main drying is carried out with a transverse stretching machine, the transparent resin film may be stretched, may be processed at the same size, or may be contracted. The amount of residual solvent of the window film substrate may be appropriately adjusted depending on the desired physical properties, but is usually 3.0% by mass or less, preferably 1.5% by mass or less, based on the window film substrate. It is preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less. When the amount of residual solvent is within the above range, the film surface is not soft and scratches are less likely to occur, so that the film can be easily handled in a subsequent step. Here, the window film is a member arranged on the surface of the image display device on the viewing side, and a protective film or other functional layer or film may be further arranged on the surface of the window film. The window film base material is a base film for a window film, and is usually used as a window film by providing a window hard coat layer for the purpose of improving the surface hardness. Depending on the purpose of use and the characteristics of the transparent resin film, the window film substrate may be used as it is as the window film. A transparent polyimide film or a transparent polyamide film is suitable as the window film substrate.

Window Film A window film comprises a window hard coat layer on at least one side of a window film base material, and has a flexible property, which is not as rigid as existing glass. A window film provided with a window film base material and a window hard coat layer on at least one surface of the window film base material is an external impact on other components of the image display device including the window film as a component or a change in ambient temperature and humidity. Will play a role of protecting from. Further, the window hard coat layer has a function of improving the surface hardness of the transparent substrate. In addition, the window hard coat layer has optical transparency and flexibility.

The thickness of the window hard coat layer of the window film is not particularly limited and may be, for example, 5 to 100 μm. When the thickness of the window hard coat layer is within the above range, sufficient surface hardness can be secured, and the problem of curling due to curing shrinkage due to decrease in flex resistance is less likely to occur. Tends to become.

The window hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiation with light or heat energy.

The window hard coat layer can be formed by curing a window hard coat composition containing a photocurable (meth)acrylate monomer or an oligomer and a photocurable epoxy monomer, or an oligomer at the same time.

The composition for window hard coat contains a solvent and a photopolymerization initiator, if necessary, in addition to the above-mentioned photocurable (meth)acrylate monomer or oligomer. Further, in the composition for window hard coat, an inorganic filler, a leveling material, a stabilizer, an antioxidant, a UV absorber, an antistatic agent, a surfactant, a lubricant, an antifouling agent, as long as the effects of the invention are not impaired. You may include additives, such as an agent.

The window hard coat layer can be formed by applying the composition for window hard coat described above to at least one surface of a window film base material and curing the composition.

Optical Laminated Product Another example of the present invention is an optical laminated product including the above-mentioned window film, and specifically, one side of the window film provided with the window hard coat layer of the present invention is provided with a polarizing plate and a touch sensor. The present invention relates to an optical layered body further including one layer selected from the group consisting of: If necessary, the window film may be provided with a polarizing plate or a touch sensor with a tacky adhesive layer in between.

At least one surface of the window film or the polarizing plate may be provided with a colored light-shielding pattern printed so as to surround a frame, and the light-shielding pattern may have a single-layer or multi-layer form. Further, a polarizing layer may be bonded to one surface of the window film directly or with an adhesive layer interposed therebetween. For example, the polarizing layer can be continuously extended to the non-display region or the bezel portion, a normal polarization including a polyvinyl alcohol-based polarizer and a protective film attached to at least one surface of the polyvinyl alcohol-based polarizer. It may be a plate.

As still another example of the present invention, a structure in which a polarizing layer and a touch sensor are integrated on one surface of the window film, the arrangement order of the polarizing layer and the touch sensor is not limited, and the window film, the polarizing layer, and the touch sensor are not limited. The display panel and the display panel may be arranged in this order, and the window film, the touch sensor, the polarizing layer and the display panel may be arranged in that order. When the window film, the polarizing layer, the touch sensor, and the display panel are arranged in this order, the touch sensor is located below the polarizing layer when the image display device is viewed from the viewing side, and thus the pattern of the touch sensor is hard to be viewed. There are advantages. In such a case, it is preferable that the substrate of the touch sensor has a front phase difference of ±2.5 nm or less. As such a material, as an unstretched film, for example, one or more materials selected from the group consisting of materials such as triacetyl cellulose, triacetyl cellulose, cycloolefin, cycloolefin copolymer, and polynorbornene copolymer. Film may be used. On the other hand, the touch sensor may have a structure in which only the pattern is transferred to the window film and the polarizing layer without the substrate.

The polarizing layer and the touch sensor can be arranged between the window film and the display panel by a transparent adhesive layer or a transparent adhesive layer, but a transparent adhesive layer is preferable. When the window film, the polarizing layer, the touch sensor, and the display panel are sequentially arranged, the transparent adhesive layer may be disposed between the window film and the polarizing layer and between the touch sensor and the display panel. When the window film, the touch sensor, the polarizing layer and the display panel are arranged in this order, the transparent adhesive layer is located between the window film and the touch sensor, between the touch sensor and the polarizing layer, and between the polarizing layer and the display panel. be able to.

Polarizing Plate The polarizing plate laminated on the window film may have a structure including a polarizer alone or a polarizer and a protective film attached to at least one surface thereof. The thickness of the polarizing plate is not particularly limited, and may be 100 μm or less, for example. If the thickness exceeds 100 μm, the flexibility may decrease. Within the above range, the thickness may be, for example, 5 to 100 μm.

The polarizer may be a film-type polarizer usually used in the art, which is produced by a process including steps such as swelling, dyeing, crosslinking, stretching, washing with water, and drying a polyvinyl alcohol-based film, and As another example, it can be formed by applying a liquid crystal coating composition as a polarizing coating layer. The liquid crystal coating composition is a coating layer forming composition and may include a polymerizable liquid crystal compound and a dichroic dye. The polarizing coating layer is formed, for example, by applying an alignment film-forming composition on a substrate, imparting alignment properties to form an alignment film, and forming a coating layer containing a liquid crystal compound and a dichroic dye on the alignment film. It can be manufactured by applying the composition to form a liquid crystal coating layer. Such a polarizing coating layer can be formed thinner than a polarizing plate including a protective film attached to both surfaces of a polyvinyl alcohol-based polarizer with an adhesive. The polarizing coating layer may have a thickness of usually 0.5 to 10 μm, preferably 2 to 4 μm.

Alignment Layer Forming Composition The alignment layer forming composition may include an aligning agent, a photopolymerization initiator and a solvent that are commonly used in the art. As the aligning agent, an aligning agent usually used in this field can be used without particular limitation. For example, a polyacrylate-based polymer, a polyamic acid, a polyimide-based polymer or a polymer containing a cinnamate group can be used as an aligning agent, and when applying photo-alignment, a polymer containing a cinnamate group should be used. Is preferred.

The application of the composition for forming an alignment film may be, for example, a spin coating method, an extrusion molding method, a dip coating, a flow coating, a spray coating, a roll coating, a gravure coating, a micro gravure coating, or the like, and preferably an inline coating method. To use. An alignment treatment is performed after the composition for forming an alignment film is applied and, if necessary, dried. For the alignment treatment, various methods well known in the art can be adopted without limitation, and preferably, photo-alignment film formation can be used. The photo-alignment film is usually obtained by applying a composition for forming a photo-alignment film containing a polymer or monomer having a photoreactive group and a solvent to a substrate and irradiating it with polarized light (preferably polarized UV). Be done. The photo-alignment film is more preferable in that the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

The thickness of the photo-alignment film is usually 10 to 10,000 nm, preferably 10 to 1,000 nm, more preferably 10 to 500 nm. When the thickness of the photo-alignment film is within the above range, the alignment regulating force is sufficiently exhibited.

Polarizing coating layer forming composition The polarizing coating layer can be formed by applying a polarizing coating layer forming composition. Specifically, the composition for forming a polarizing coating layer is a composition containing one or more polymerizable liquid crystals (hereinafter sometimes referred to as polymerizable liquid crystal (B)) as a host compound in addition to a dichroic dye (hereinafter, referred to as a polymerizable liquid crystal (B)). , Sometimes referred to as composition B).

The “dichroic dye” means a dye having a property that the absorbance in the major axis direction of the molecule is different from the absorbance in the minor axis direction. The dichroic dye is not limited as long as it has such properties, and may be a dye or a pigment. Two or more dyes may be used in combination, two or more pigments may be used in combination, and a dye and a pigment may be used in combination.

The dichroic dye preferably has a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes, and among them, azo dyes are preferable. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes and stilbeneazo dyes, with bisazo dyes and trisazo dyes being preferred.

The liquid crystal state of the polymerizable liquid crystal (B) is preferably a smectic phase, and more preferably a higher order smectic phase in that a polarizing layer having a higher degree of alignment order can be produced. The polymerizable liquid crystal (B) exhibiting a smectic phase is referred to as a polymerizable smectic liquid crystal compound. The polymerizable liquid crystal (B) can be used alone or in combination. When two or more kinds of polymerizable liquid crystals are combined, at least one kind is preferably the polymerizable liquid crystal (B), and more preferably, two kinds or more is the polymerizable liquid crystal (B). By combining them, the liquid crystallinity may be temporarily retained even at a temperature below the liquid crystal-crystal phase transition temperature. The polymerizable liquid crystal (B) is described in, for example, Lub et al. Recl. Trav. Chim. It is produced by a known method described in Pays-Bas, 115, 321-328 (1996) or Japanese Patent No. 4719156. The content of the dichroic dye in the composition B can be appropriately adjusted depending on the type of the dichroic dye and the like, but is preferably 0.1 part by mass or more and 50 parts by mass or more per 100 parts by mass of the polymerizable liquid crystal (B). It is not more than 10 parts by mass, more preferably not less than 0.1 parts by mass and not more than 20 parts by mass, still more preferably not less than 0.1 parts by mass and not more than 10 parts by mass. When the content of the dichroic dye is within this range, the polymerizable liquid crystal (B) can be polymerized without disturbing the orientation.

Composition B preferably contains a solvent. In general, a smectic liquid crystal compound has a high viscosity, so that a composition containing a solvent is easy to apply, and as a result, a polarizing film is often formed easily. Examples of the solvent include the same solvents as those contained in the above-mentioned oriented polymer composition, and can be appropriately selected depending on the solubility of the polymerizable liquid crystal (B) and the dichroic dye. The content of the solvent is preferably 50 to 98 mass% with respect to the total amount of the composition B. In other words, the solid content in the composition B is preferably 2 to 50% by mass.

Composition B preferably contains one or more leveling agents. The leveling agent has the function of adjusting the fluidity of the composition B and making the coating film obtained by applying the composition B more flat, and specific examples thereof include a surfactant. When the composition B contains a leveling agent, its content is preferably 0.05 parts by mass or more and 0.05 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal. Below the section. When the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal, the polarizing layer obtained tends to be smoother, and the resulting polarizing layer is less uneven. Tend not to.

Composition B preferably contains one or more polymerization initiators. The polymerization initiator is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal (B), and a photopolymerization initiator is preferable in that the polymerization reaction can be initiated under lower temperature conditions. As a photopolymerization initiator. Specific examples include photopolymerization initiators capable of generating active radicals or acids by the action of light, and of these, photopolymerization initiators capable of generating radicals by the action of light are preferred. Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts and sulfonium salts.

When the composition B contains a polymerization initiator, the content thereof can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal contained in the composition, and is based on 100 parts by mass of the polymerizable liquid crystal. , Preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, still more preferably 0.5 to 8 parts by mass. When the content of the polymerization initiator is within this range, the polymerizable liquid crystal (B) can be polymerized without disturbing the orientation. When the composition B contains a photopolymerization initiator, the composition may further contain a photosensitizer. When the composition B contains a photopolymerization initiator and a photosensitizer, the polymerization reaction of the polymerizable liquid crystal contained in the composition can be further promoted. The amount of the photosensitizer used can be appropriately adjusted depending on the types and amounts of the photopolymerization initiator and the polymerizable liquid crystal, but is preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal. The amount is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass.

In order to make the polymerization reaction of the polymerizable liquid crystal proceed more stably, the composition B may contain an appropriate amount of a polymerization inhibitor, which makes it easy to control the degree of progress of the polymerization reaction of the polymerizable liquid crystal. .. When the composition B contains a polymerization inhibitor, the content thereof can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal, the amount of the photosensitizer used, and the like. It is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 0.5 to 8 parts by mass. When the content of the polymerization inhibitor is within this range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal.

Method for producing polarizing coating layer The polarizing coating layer is usually formed by applying a composition for forming a polarizing coating layer on a substrate that has been subjected to an alignment treatment, and polymerizing the polymerizable liquid crystal in the obtained coating film. .. The method of applying the composition for forming a polarizing coating layer is not limited. As the alignment treatment, those exemplified above can be mentioned. A dried coating film is formed by applying the composition for forming a polarizing coating layer, and removing the solvent by drying under the condition that the polymerizable liquid crystal contained in the obtained coating film does not polymerize. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a reduced pressure drying method. When the polymerizable liquid crystal is a polymerizable smectic liquid crystal compound, it is preferable to change the liquid crystal state of the polymerizable smectic liquid crystal compound contained in the dried film to a nematic phase (nematic liquid crystal state) and then to transition to the smectic phase. In order to form the smectic phase through the nematic phase, for example, the dry coating is heated to a temperature at which the polymerizable smectic liquid crystal compound contained in the dry coating transitions to the liquid crystal state of the nematic phase, and then the polymerizable smectic is added. A method is adopted in which the liquid crystal compound is cooled to a temperature at which it exhibits a liquid crystal state of a smectic phase. Next, a method of causing the polymerizable liquid crystal in the dry film to have a liquid crystal state in a smectic phase and then photopolymerizing the polymerizable liquid crystal while maintaining the liquid crystal state in the smectic phase will be described. In the photopolymerization, the light to be applied to the dry film depends on the kind of the photopolymerization initiator contained in the dry film, the kind of the polymerizable liquid crystal (particularly, the kind of the photopolymerizable group contained in the polymerizable liquid crystal) and the amount thereof. It can be appropriately selected, and specific examples thereof include active energy rays selected from the group consisting of visible light, ultraviolet light and laser light. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and a photopolymerization device widely used in the art can be used. By performing photopolymerization, the polymerizable liquid crystal is polymerized while maintaining the liquid crystal state of a smectic phase, preferably a higher order smectic phase, to form a polarizing layer.

Retardation Coating Layer In an embodiment of the present invention, the polarizing plate may include a retardation coating layer. The retardation coating layer is a generic term for a λ/2 layer, a λ/4 layer, a positive C layer, etc. depending on the optical characteristics. The retardation coating layer is formed, for example, by applying a coating layer forming composition containing a liquid crystal compound on a base material film that has been subjected to an alignment treatment to form a liquid crystal coating layer, and then polarizing the liquid crystal coating layer through an adhesive layer. It can be formed by adhering it to a plate and then peeling the substrate film, but the method is not limited to this method. As the substrate film, the polymer film exemplified as the protective film can be used, and the substrate surface on the side where the alignment film and the retardation layer are formed is subjected to a surface treatment before forming the alignment film. You can also The composition for forming an alignment film and the method for coating and drying the same are the same as those described for the polarization coating layer, and thus the description thereof is omitted to avoid duplication. The composition of the coating layer forming composition is the same as that described for the polarizing coating layer, except that it does not contain a dichroic dye. In addition, the method of applying, drying, and curing the coating layer-forming composition is the same as that described for the polarizing coating layer, and thus the description thereof is omitted to avoid duplication.

The thickness of the retardation coating layer may be 0.5-10 μm, preferably 1-4 μm.

In one embodiment of the present invention, the optical properties of the retardation coating layer can be adjusted according to the thickness of the coating layer, the alignment state of the polymerizable liquid crystal compound, and the like. Specifically, by adjusting the thickness of the retardation layer, a retardation layer that gives a desired in-plane retardation can be manufactured. The in-plane retardation value (in-plane retardation value, Re(λ)) is a value defined by Equation (1), and Δn and the thickness (d) are calculated in order to obtain a desired Re(λ). It is good to adjust.
Re(λ)=d×Δn... (1) (where Δn=nx−ny)
(In Formula (1), Re(λ) represents an in-plane retardation value at wavelength λ, d represents thickness, and Δn represents birefringence. Refractive index formed by alignment of polymerizable liquid crystal compound When considering an ellipsoid, the refractive indices in three directions, that is, nx, ny and nz are defined as follows, where nx is the direction parallel to the substrate plane in the refractive index ellipsoid formed by the retardation layer. Represents the main refractive index of ny, is parallel to the base plane of the index ellipsoid formed by the retardation layer, and represents the refractive index in the direction orthogonal to the nx direction, and nz is the retardation layer. Represents the refractive index in the direction perpendicular to the substrate plane in the refractive index ellipsoid formed by When the retardation layer is a λ/4 layer, the in-plane retardation value Re(550) is preferably 113 to 163 nm. , And more preferably 130 to 150 nm. When the retardation layer is a λ/2 layer, Re(550) is preferably 250 to 300 nm, more preferably 250 to 300 nm.)

Further, a retardation layer that exhibits a retardation in the thickness direction can be manufactured according to the alignment state of the polymerizable liquid crystal compound. The expression of the retardation in the thickness direction means that the retardation value Rth in the thickness direction is negative in the following mathematical expression (2).
Rth=[(nx+ny)/2-nz]×d (2)
(In the formula (2), nx, ny, nz and d have the same definition as described above.)
The in-plane retardation value Re(550) at a wavelength of 550 nm of the positive C layer is usually 0 to 10 nm, preferably 0 to 5 nm, and the retardation value Rth in the thickness direction is usually -10 to -300 nm, preferably -20. ~-200 nm. The polarizing plate of the present invention may have two or more retardation coating layers, and when it has two retardation coating layers, the first retardation coating layer is a λ/4 layer for making circularly polarized light. In addition, the second retardation coating layer may be a positive C layer for improving the tint when viewed obliquely. In addition, the first retardation coating layer may be a positive C layer for improving the tint when viewed obliquely, and the second retardation coating layer may be a λ/4 layer for making circularly polarized light.

Adhesive Layer In one embodiment of the present invention, the polarizing coating layer and the first retardation coating layer, or the first retardation coating layer and the second retardation coating layer may be attached via an adhesive or an adhesive. it can. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive or a thermosetting adhesive can be used, and preferably a water-based adhesive or an active energy ray-curable adhesive. What is mentioned later can be used as the adhesive layer.

Examples of the water-based adhesive for the adhesive layer include an adhesive made of a polyvinyl alcohol-based resin aqueous solution and an aqueous two-component urethane-based emulsion adhesive. Above all, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is preferably used. Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying a polymer, a modified polyvinyl alcohol-based polymer obtained by partially modifying a hydroxyl group thereof, or the like can be used. The water-based adhesive may contain a crosslinking agent such as an aldehyde compound (glyoxal or the like), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, a polyvalent metal salt or the like.

When a water-based adhesive is used, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after the coating layer is bonded.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet ray curable adhesive agent. Is.

The curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of the cationically polymerizable curable compound include epoxy compounds (compounds having one or more epoxy groups in the molecule) and oxetane compounds (one or more oxetane rings in the molecule). Or a combination thereof. Examples of the radical-polymerizable curable compound include a (meth)acrylic compound (compound having one or more (meth)acryloyloxy groups in the molecule) and a radical-polymerizable double bond. Other vinyl compounds or combinations thereof may be mentioned. You may use together a cationically polymerizable curable compound and a radically polymerizable curable compound. The active energy ray-curable adhesive usually further contains a cationic polymerization initiator and/or a radical polymerization initiator for initiating a curing reaction of the curable compound.

In pasting the coating layer, surface activation treatment may be performed on at least one of the pasting surfaces in order to enhance the adhesiveness. As surface activation treatment, dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing actinic ray treatment (ultraviolet treatment, electron beam treatment, etc.) Ultrasonic treatment using a solvent such as water or acetone, saponification treatment, and wet treatment such as anchor coating treatment can be mentioned. These surface activation treatments may be performed alone or in combination of two or more.

The thickness of the adhesive layer can be adjusted according to the adhesive force, and may be usually 0.1 to 10 μm, preferably 1 to 5 μm. In an embodiment of the present invention, when the plurality of adhesive layers are used, the adhesive layers may be made of the same material or different materials, and may have the same thickness or different thicknesses.

Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive composition containing a resin such as a (meth)acrylic resin, a rubber resin, a polyurethane resin, a polyester resin, a silicone resin, or a polyvinyl ether resin as a main component. can do. Among them, a pressure-sensitive adhesive composition containing a polyester-based resin or a (meth)acrylic resin, which is excellent in transparency, weather resistance, heat resistance, etc., as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.
The weight average molecular weight of the pressure-sensitive adhesive resin used in the present invention is usually 300,000 to 4,000,000, and preferably 500,000 to 3,000,000, more preferably from the viewpoint of durability, particularly heat resistance. It is preferably 650,000 to 2,000,000. When the weight average molecular weight is within the above range, it is preferable from the viewpoint of heat resistance, and it is preferable that the bondability and the adhesive force are not easily lowered. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

Further, the pressure-sensitive adhesive composition may contain a crosslinking agent. As the cross-linking agent, an organic cross-linking agent or a polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent. The polyfunctional metal chelate is a polyvalent metal having a covalent bond or a coordinate bond with an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn and Ti. can give. Examples of the atom in the organic compound that forms a covalent bond or a coordinate bond include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

The amount of the cross-linking agent used is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass with respect to 100 parts by mass of the adhesive resin. When the amount of the cross-linking agent used is within the above range, the cohesive force of the pressure-sensitive adhesive layer tends to be insufficient, and the possibility of foaming during heating is reduced, and the moisture resistance is sufficient, and the reliability is high. Peeling is less likely to occur in a sex test or the like.

It is preferable to add a silane coupling agent as an additive. As the silane coupling agent, a silicon compound having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; Amino group-containing silicon compound such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane; 3-chloro Propyltrimethoxysilane; (meth)acryl group-containing silane coupling agents such as acetoacetyl group-containing trimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane; 3-isocyanatopropyltriethoxysilane Isocyanate group-containing silane coupling agents such as The silane coupling agent can impart durability, particularly an effect of suppressing peeling under a humid environment. The amount of the silane coupling agent used is preferably 1 part by mass or less, more preferably 0.01 to 1 part by mass, still more preferably 0.02 to 0.6 part by mass, relative to 100 parts by mass of the adhesive resin. is there.

Furthermore, the pressure-sensitive adhesive composition may contain other known additives. For example, the pressure-sensitive adhesive composition may include powders such as colorants and pigments, dyes, surfactants, plasticizers, and tackiness agents. Additives, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, foils, etc. Can be appropriately added depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range.

The thickness of the pressure-sensitive adhesive layer is not particularly limited and is, for example, about 1 to 100 μm, preferably 2 to 50 μm, and more preferably 3 to 30 μm.

Protective layer In an embodiment of the present invention, the polarizing plate may have a form having at least one protective layer, and one surface of a polarizer forming the polarizing plate or a case where the polarizer has a retardation layer. Can be located on the surface of the retardation layer opposite to the polarizer.

The protective layer is not particularly limited as long as it is a film excellent in transparency, mechanical strength, heat stability, moisture shielding property, isotropy and the like. Specifically, polyester-based films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; cellulose-based films such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based films; acrylics such as polymethyl (meth)acrylate and polyethyl (meth)acrylate. Styrene film such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin film such as cycloolefin, cycloolefin copolymer, polynorbornene, polypropylene, polyethylene and ethylene propylene copolymer; Vinyl chloride film; Nylon Polyamide film such as aromatic polyamide, imide film, sulfone film, polyetherketone film, polyphenylene sulfide film, vinyl alcohol film, vinylidene chloride film, vinyl butyral film, arylate film, polyoxy Examples thereof include a methylene-based film, a urethane-based film, an epoxy-based film, and a silicone-based film. Among these, a cellulosic film having a surface saponified with alkali or the like is particularly preferable in consideration of polarization characteristics or durability. The protective layer may also have an optical compensation function such as a retardation function.

The protective layer may be one in which the surface to be bonded to the polarizer or the retardation coating layer is subjected to an easy-adhesion treatment for improving the adhesive strength. The easy-adhesion treatment is not particularly limited as long as it can improve the adhesive strength, and examples thereof include dry treatment such as primer treatment, plasma treatment, corona treatment; chemical treatment such as alkali treatment (saponification treatment); low-pressure UV treatment, etc. Can be mentioned.

Touch Sensor The touch sensor includes a base material, a lower electrode provided on the base material, an upper electrode facing the lower electrode, and an insulating layer sandwiched between the lower electrode and the upper electrode.

As the base material, various materials can be used as long as it is a flexible resin film having a light-transmitting property. For example, as the substrate, the film exemplified as the material of the transparent substrate can be used.

The lower electrode has, for example, a plurality of small electrodes each having a square shape in a plan view. The plurality of small electrodes are arranged in a matrix.

Further, the plurality of small electrodes are connected to each other by the small electrodes adjacent to each other in one diagonal direction of the small electrodes to form a plurality of electrode rows. The plurality of electrode rows are connected to each other at their ends, and the electric capacitance between adjacent electrode rows can be detected.

The upper electrode has, for example, a plurality of small electrodes each having a square shape in a plan view. The plurality of small electrodes are complementarily arranged in a matrix at a position where the lower electrode is not arranged in a plan view. That is, the upper electrode and the lower electrode are arranged without a gap in plan view.

Further, the plurality of small electrodes are connected by the small electrodes adjacent to each other in the other diagonal direction of the small electrodes to form a plurality of electrode rows. The plurality of electrode rows are connected to each other at their ends, and the electric capacitance between adjacent electrode rows can be detected.

The insulating layer insulates the lower electrode and the upper electrode. As a material for forming the insulating layer, a material generally known as a material for the insulating layer of the touch sensor can be used.

In the present embodiment, the touch sensor has been described as being a so-called projected capacitive touch sensor. However, as long as the effect of the invention is not impaired, a touch sensor of another method such as a film resistance method is used. Can also be adopted.

Light-shielding pattern The light-shielding pattern may be provided as at least a part of a bezel or a housing of a window film or a display device to which the window film is applied. For example, each wiring of the display device may be hidden by the light-shielding pattern and may not be visually recognized by the user. The color and/or material of the light-shielding pattern is not particularly limited, and can be formed of a resin material having various colors such as black, white, and gold. For example, the light-shielding pattern can be formed of a resin material such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or silicone mixed with a pigment for realizing a color. The material and thickness of the light blocking pattern may be determined in consideration of protection and flexibility of the window film or the display device. In addition, these can be used alone or as a mixture of two or more kinds.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "parts" in the examples are mass% and parts by mass. The present invention is not limited to these examples.

Production Example 1: Preparation of transparent polyimide polymer A separable flask was equipped with a silica gel tube, a stirrer and a thermometer, and an oil bath. In this flask, 75.52 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB) were added. 54.44 g was added. While stirring this at 400 rpm, 519.84 g of N,N-dimethylacetamide (DMAc) was added, and the stirring was continued until the content in the flask became a uniform solution. Then, stirring was continued for another 20 hours while adjusting the temperature inside the container to be in the range of 20 to 30° C. using an oil bath to cause a reaction to generate a polyamic acid. After 30 minutes, the stirring speed was changed to 100 rpm. After stirring for 20 hours, the reaction system temperature was returned to room temperature, and DMAc (649.8 g) was added to adjust the polymer concentration to 10% by mass. Further, 32.27 g of pyridine and 41.65 g of acetic anhydride were added, and the mixture was stirred at room temperature for 10 hours for imidization. The polyimide varnish was taken out from the reaction container. The obtained polyimide varnish was dropped into methanol for reprecipitation, the obtained powder was dried by heating to remove the solvent, and a transparent polyimide polymer was obtained as a solid content. When the GPC measurement of the obtained polyimide polymer was performed, the weight average molecular weight was 360,000. The polyimide polymer was dissolved at a concentration of 16.5% in a solvent in which γ-butyrolactone and N,N-dimethylacetamide were mixed at a ratio of 1:9 to obtain a resin varnish.

Production Example 2: Preparation of transparent polyamide-imide-based polymer Under a nitrogen gas atmosphere, TFMB 50 g (156.13 mmol) and DMAc 642.07 g were added to a 1 L separable flask equipped with a stirring blade, and TFMB was converted into DMAc while stirring at room temperature. Dissolved. Next, 20.84 g (46.91 mmol) of 6FDA was added to the flask and stirred at room temperature for 3 hours. After that, 9.23 g (31.27 mmol) of 4,4′-oxybis(benzoyl chloride) (OBBC) and then 15.87 g (78.18 mmol) of terephthaloyl chloride (TPC) were added to the flask and stirred at room temperature for 1 hour. did. Next, 9.89 g (106.17 mmol) of 4-methylpyridine and 14.37 g (140.73 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70° C. using an oil bath, The mixture was further stirred for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a filament form, the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Next, the precipitate was dried under reduced pressure at 100° C. to obtain a transparent polyamideimide polymer. GPC measurement of the obtained polyamideimide-based polymer revealed that the weight average molecular weight was 420,000. The transparent polyimide-based polymer was dissolved in a mixed solvent in which γ-butyrolactone (GBL) and DMAc were mixed at a ratio of 1:9 at a solid content concentration of 16.5% to obtain a resin varnish.

Production Example 3: Preparation of silica sol Amorphous silica sol having a BET diameter (average particle diameter measured by the BET method) of 27 nm produced by the sol-gel method was used as a raw material, and γ-butyrolactone (hereinafter referred to as GBL) was obtained by solvent substitution. Sometimes a substituted silica sol was prepared. The obtained sol was filtered with a membrane filter having an opening of 10 μm to obtain a GBL-substituted silica sol. In each of the obtained GBL-substituted silica sols, silica particles were 30 to 32% by mass. The transparent polyamideimide polymer obtained in Production Example 2 was dissolved in GBL, and the GBL-substituted silica sol obtained in Production Example 3 was added and mixed sufficiently to obtain a transparent polyamide having the composition shown in Table 1. An imide polymer/silica particle mixed varnish (hereinafter sometimes referred to as mixed varnish) was obtained. At that time, the mixed varnish was prepared so that the concentration of the polyamideimide polymer/silica particles (concentration with respect to the total mass of the resin and silica particles) was 10% by mass.

Example 1
The resin varnish of Production Example 1 had a thickness of 198 μm (PET 188 μm having a double-sided easy-adhesion layer + double-sided hard coat layer 5 μm), a width of 1300 mm, and a Martens hardness of 410 N/ on the cast film forming surface side and the opposite surface (that is, the hard coat layer surface side). made by coating a polyethylene terephthalate (PET) film support (support A: base resin=PET, double-sided HC treated) having a long hard coat (HC) layer having a width of 1200 mm with a width of 1200 mm by a casting method. Filmed The solvent is removed from the resin solution by passing the film-formed resin varnish through a furnace having a length of 12 m set to gradually change the temperature from 70° C. to 120° C. at a linear velocity of 0.4 m/min. To form a transparent resin film (thickness 80 μm). After that, a protective film (Toretec (registered trademark) N711A manufactured by Toray Film Kako Co., Ltd., a polyolefin protective film with weak adhesive strength) is attached to the transparent resin film, and a PET film having a protective film, a transparent resin film, and a hard coat layer. The film-shaped laminated body composed of was wound around a roll core to form a roll.

Peeling test of laminate Whether the peeling occurs between the support and the transparent resin film after winding the obtained laminate on a cylindrical rod having a predetermined diameter by 180° and leaving it to stand for 1 minute in that state. Is visually confirmed. If peeling occurs even in a part, it is considered that peeling occurs.
When a peeling test was performed on the laminate obtained in Example 1, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm and 20 mm by 180°.

The support A was peeled off while unwinding the rolled-up laminated body, and the laminated body composed of the transparent resin film and the protective film was wound up.

The protective film was peeled off from the laminate of the transparent resin film and the protective film obtained in Example 1 above, and the scratches on the support and the transparent resin film were evaluated as follows, and shown in Table 1. In addition, haze, total light transmittance, yellow index, and residual solvent amount were also measured as described below. The results are shown in Table 1.

Evaluation of scratches on the support A 1,600 lumen LED light was used for the support after the transparent resin substrate was peeled off, and light was irradiated from the flow direction and the width direction of the film to visually observe the presence or absence of scratches.
⊚: Scratches are not visible ◯: Scratches are slightly visible ×: Scratches are clearly visible
The results of the scratch evaluation are shown in Table 1.

Evaluation of scratches on transparent resin film The transparent resin film peeled from the support was irradiated with HID portable searchlight PS-X1 (light flux 3,400 lumens) manufactured by POLARION to visually check for scratches. At this time, first, light was irradiated from the flow direction of the film to confirm the presence or absence of scratches, and subsequently, it was also irradiated from the width direction to confirm scratches. The light is applied to the film surface at an angle of about 20 to 70°. The direction of visual recognition is from just above the surface of the transparent resin film to be evaluated (angle of 90° from the resin film surface). In addition, when the protective film is laminated on the surface of the transparent resin film opposite to the support, the protective film is peeled off and the presence or absence of scratches is confirmed.
Evaluation Criteria ⊚: No scratches are visible ◯: Slight scratches are visible ×: Scratches are clearly visible

Haze The haze of the transparent resin film was measured by a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. according to JIS K 7105:1981. The results are shown in Table 1. When a protective film is laminated on the surface of the transparent resin film opposite to the support, the protective film is peeled off and the haze is measured.

Total Light Transmittance The total light transmittance of the transparent resin film was measured by a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. according to JIS K 7105:1981. The results are shown in Table 1. When a protective film is laminated on the surface of the transparent resin film opposite to the support, the protective film is peeled off and the total light transmittance is measured.

Yellow index (yellowness: YI value)
The yellow index (yellowness: YI value) of the transparent resin film was measured with an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation. After performing the background measurement in the absence of the sample, the transparent resin film was set in the sample holder, the transmittance for light of 300 to 800 nm was measured, and the tristimulus values (X, Y, Z) were obtained. The YI value was calculated based on the following formula. When the protective film is laminated on the surface of the transparent resin film opposite to the support, the protective film is peeled off and the yellow index is measured.
YI value=100×(1.2769X-1.0592Z)/Y

Method for Measuring Residual Solvent Thermogravimetric-Differential Heat (TG-DTA) Measurement As a measuring device for TG-DTA, TG/DTA6300 manufactured by Hitachi High-Tech Science Co., Ltd. was used. A sample of about 20 mg was obtained from the produced transparent resin film. This sample was heated from room temperature to 120° C. at a heating rate of 10° C./min, held at 120° C. for 5 minutes, and then heated (heated) to 400° C. at a heating rate of 10° C./min. The change in mass of the sample was measured.
From the TG-DTA measurement result, the mass reduction rate S (mass %) from 120° C. to 250° C. was calculated according to the following formula.
S (mass %)=100−(W1/W0)×100
[In the formula, W0 is the mass of the sample after holding at 120° C. for 5 minutes, and W1 is the mass of the sample at 250° C.].
The calculated mass reduction rate S was defined as the residual solvent amount S (mass %) in the transparent resin film. When a protective film is laminated on the surface of the transparent resin film opposite to the support, the protective film is peeled off and the amount of residual solvent is measured.

Elastic Film Measurement of Transparent Resin Film The optical film obtained by peeling the support from the laminates obtained in Examples, Comparative Examples and Reference Examples was cut into a strip of 10 mm×100 mm using a dumbbell cutter, and a sample was obtained. Got The elastic modulus of this sample was measured using an autograph AG-IS manufactured by Shimadzu Corporation under the conditions of a chuck distance of 500 mm and a pulling speed of 20 mm/min, and the elastic modulus (GPa) of the optical film was calculated from the inclination. Calculated.

For the support, Table 2 shows the type and thickness of the base resin and the thickness of the hard coat layer. Moreover, the following measurement was performed. The results are shown in Table 2.

Method for measuring Martens hardness After cutting the above support into a size of 40 mm × 40 mm, the surface opposite to the side for cast film formation is bonded to a glass of 40 mm × 40 mm through an adhesive layer having a thickness of 20 μm. did. The surface of the support, which is bonded to the glass, on which the cast film is to be formed is, in an atmosphere of 23° C. and 55% RH, an ultra-micro hardness tester (FISCHERSCOPE HM2000: manufactured by Fisher Instruments Co., Ltd.) and a Vickers indenter is used. After using, a load was applied at a pressing rate of 0.5 mN/5 seconds, and then a load of 0.5 mN was maintained for 5 seconds for measurement. Martens hardness was similarly measured on the surface not cast (non-cast surface), and the values are shown in Table 2. The description method is described in the form of Martens hardness of cast surface/Martens hardness of non-cast surface. The Martens hardness is measured on the support before cast film formation.

Measurement of Arithmetic Average Roughness (Ra) and Maximum Height (Rz) The surface of the above support on which the cast film is to be formed is calculated according to JIS B 0601-2001 using a surf coder ET3000 manufactured by Kosaka Laboratory Ltd. The average roughness (Ra) and the maximum height (Rz) were measured. The results are shown in Table 2. The arithmetic average roughness (Ra) and the maximum height (Rz) of the surface not cast (non-cast surface) were similarly measured, and the values are shown in Table 2. The description method is described in the form of the measured value of the cast surface/the measured value of the non-cast surface. The arithmetic mean roughness (Ra) and the maximum height (Rz) are measured on the support before cast film formation.

While unrolling the laminate roll of the protective film and the transparent resin film of Example 1, the transparent resin film was introduced into a drying oven and further dried (main drying) while peeling off the protective film. The temperature of the drying furnace was 200° C., the conveying speed was 1.0 m/min, and the drying time was 12 minutes. The transparent resin film after drying in a drying oven was laminated on one surface with a protective film (Tretec 7332K manufactured by Toray Film Machinery Co., Ltd., a polyolefin protective film with weak adhesive strength) and wound on a roll core. When the protective film was peeled off and the residual solvent amount of the transparent resin film after the main drying was measured, it was 1%. The transparent resin film obtained by this drying can also be used as a window film base material.

Evaluation of heat shrinkage rate and precipitate of support A4 size support is cut out from the center in the width direction of a support base material having a width of 1,300 mm and placed in an oven at 120°C to measure the shrinkage rate (%) before and after. did. In that case, it is shown in Table 2 as% of machine direction (MD)/% of vertical method (TD). Furthermore, after heating, it was confirmed using an LED light of 1600 lumens whether there was any deposit on the surface.
Measurement conditions for contact angle with water (before washing) A 1 mL of ultrapure water was dropped on the cast film-forming surface of the support, and using a contact angle meter DM500 manufactured by Kyowa Interface Science Co., Ltd., the following method was used. The contact angle was measured. The same measurement was performed 10 times, and the average value is shown in Table 2.
Method: Drop method Method: θ/2 method Curvature correction: None Liquid: Ultrapure water Liquid volume: 1 mL
Measurement timing: 1,000 ms after dropping Data processing: N=10 Measured and averaged

Measurement of water contact angle (after washing) B On the cast film-forming surface of the support, γ-butyrolactone (GBL) was dropped so as to cover all contact angle measurement points, and the mixture was allowed to stand for 1 minute, and then GBL was dipped. Clean with a clean room waste (Savina Minimax (registered trademark) Wiping Cloth manufactured by KB Seiren Co., Ltd.) (slide back and forth 5 times), and dry until the GBL remains are no longer visible. I wiped it dry. Then, it was left to stand for 5 minutes to be dried. Then, measurement was performed using ultrapure water (1 mL) as in the case of the contact angle A with water, and the average value of 10 measurements is shown in Table 2. The value of |BA| was also calculated and shown in Table 2.

Example 2
The transparent polyamideimide-based polymer thus obtained was dissolved in GBL, and the GBL-substituted silica sol obtained in Production Example 3 was added and sufficiently mixed to obtain a transparent polyamideimide-based polymer/silica particle mixed varnish (hereinafter, Sometimes referred to as mixed varnish). At that time, the mixed varnish was prepared so that the concentration of the polyamideimide polymer/silica particles (concentration with respect to the total mass of the resin and silica particles) was 10% by mass. After that, the obtained mixed varnish was processed to have a thickness of 194 μm (PET 188 μm having a double-sided easy-adhesion layer + double-sided hard coat layer 3 μm), width of 1,300 mm, cast film forming surface side and opposite surfaces (that is, both hard coat layer sides). Of a polyethylene terephthalate (PET) film having a long hard coat layer having a Martens hardness of 406 N/mm (support B: base resin=PET, with HC treatment) is applied with a width of 1200 mm by a casting method. The film was formed. The solvent was removed from the resin solution by passing the film-formed mixed varnish through a furnace having a length of 12 m set to gradually change the temperature from 70° C. to 120° C. at a linear velocity of 0.4 m/min. To form a transparent resin film (thickness 50 μm). After that, a protective film (Torefan (registered trademark) 25-MK01 manufactured by Toray Industries, Inc., a polyolefin protective film) is attached to the transparent resin film, and the protective film is composed of a PET film having a transparent resin film and a hard coat layer. The film-shaped laminated body was wound around a roll core to form a roll.

When a peeling test was performed on the laminate obtained in Example 2, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm, and 20 mm by 180°.

The support B was peeled off while unwinding the rolled-up laminated body, and the laminated body composed of the transparent resin film and the protective film was wound up. By the same method as in Example 1, the evaluation of scratches, haze, total light transmittance, yellow index and residual solvent amount of the support and the transparent resin film from which the protective film was peeled off were evaluated. Regarding the support, the Martens hardness (cast surface/non-cast surface), arithmetic mean roughness (Ra: cast surface/non-cast surface), maximum height (Rz: cast surface/non-cast surface), heat shrinkage ratio ( MD/TD) and the presence or absence of precipitates were also measured. The results are shown in Tables 1 and 2.

While unwinding the laminate roll of the protective film of Example 2 and the transparent resin film, while peeling off the protective film, the transparent resin film was introduced into a drying oven and further dried (main drying). The temperature of the drying furnace was 200° C., the conveying speed was 1.0 m/min, and the drying time was 12 minutes. The transparent resin film after drying in a drying oven was laminated with a protective film (Trephan 25-MK01 manufactured by Toray Industries, Inc., a polyolefin protective film) on one surface and wound on a roll core. When the protective film was peeled off and the amount of residual solvent in the transparent resin film after the main drying was measured, it was 0.6%. The transparent resin film obtained by this drying can also be used as a window film base material.

Example 3
190 μm thick as a support (PET 188 μm with double-sided easy-adhesion layer + 1 μm hard coat layer), width 1,300 mm, long hard with a Martens hardness of 390 N/mm on the cast film forming surface side (that is, hard coat layer surface) A protective film, a transparent resin film and a hard coat layer were treated in the same manner as in Example 2 except that a polyethylene terephthalate (PET) film having a coat layer (support C: base resin=PET, both sides treated with HC) was used. A roll of a laminate composed of a PET film having

When a peeling test was conducted on the laminate obtained in Example 3, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm and 20 mm by 180°.

The support C was peeled off while unwinding the laminate wound up in a roll as described above, and the laminate composed of the transparent resin film and the protective film was wound up. By the same method as in Example 1, the evaluation of scratches, haze, total light transmittance, yellow index and residual solvent amount of the support and the transparent resin film from which the protective film was peeled off were evaluated. Regarding the support, the Martens hardness (cast surface/non-cast surface), arithmetic mean roughness (Ra: cast surface/non-cast surface), maximum height (Rz: cast surface/non-cast surface), heat shrinkage ratio ( MD/TD) and the presence or absence of precipitates were also measured. The results are shown in Tables 1 and 2.

While unrolling the laminate roll of the protective film of Example 3 and the transparent resin film, while peeling off the protective film, the transparent resin film was introduced into a drying oven and further dried (main drying). The temperature of the drying furnace was 200° C., the conveying speed was 1.0 m/min, and the drying time was 12 minutes. After the transparent resin film was dried in a drying oven, a protective film (Mastak (registered trademark) AY(75)-638, PET-based protective film manufactured by Fujimori Kogyo Co., Ltd.) was attached to one surface and wound on a roll core. I took it. When the protective film was peeled off and the amount of residual solvent in the transparent resin film after the main drying was measured, it was 0.6% by mass. The transparent resin film obtained by this drying can also be used as a window film base material.

Example 4
Preparation of Support D A coating solution for hard coat layer was prepared according to the following formulation.
Component portion dendrimer structure polyfunctional oligomer ^{A1 * a} 8 parts photopolymerizable prepolymer / photopolymerizable monomer ^* b 12 parts Photopolymerization initiator ^* C 0.6 parts of propylene glycol monomethyl ether 45 parts * a: miwon-Specialty Chemicals Miramer SP1114 (solid content 100%) commercially available from Co., Ltd.
*B: Beam Set 575 (100% solid content) manufactured by Arakawa Chemical Industries, Ltd.
*C: Irgacure 651 available from BASF Japan Ltd.

The above formulations were mixed to prepare a coating liquid for hard coat layer. Using a micro gravure coating device, a PET film roll (Cosmoshine (registered trademark) A4100 manufactured by Toyobo Co., Ltd.) having a double-sided easy-adhesion layer having a thickness of 188 μm was unwound, and the obtained coating liquid for hard coat layer was obtained. , Coated on both sides of the PET film for easy adhesion treatment, dried, and then irradiated with ultraviolet rays from a high pressure mercury lamp (irradiation amount 400 mJ/cm ² ) to form a hard coat layer having a thickness of 3 μm on both sides of the PET film, A PET film roll having a hard coat layer (support D: base resin=PET, both sides treated with HC) was wound into a roll shape. The Martens hardness of the cast film forming surface (that is, the hard coat layer surface) was 330 N/mm.

Formation of transparent resin film A laminate comprising a protective film, a transparent resin film, and a PET film having a hard coat layer in the same manner as in Example 2 except that the support D was used as the support for cast film formation. Got a roll of.

When a peeling test was performed on the laminate obtained in Example 4, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm, and 20 mm by 180°.

The support D was peeled off while unwinding the rolled-up laminated body, and the laminated body composed of the transparent resin film and the protective film was wound up. By the same method as in Example 1, the evaluation of scratches, haze, total light transmittance, yellow index and residual solvent amount of the support and the transparent resin film from which the protective film was peeled off were evaluated. Regarding the support, the Martens hardness (cast surface/non-cast surface), arithmetic mean roughness (Ra: cast surface/non-cast surface), maximum height (Rz: cast surface/non-cast surface), heat shrinkage ratio ( MD/TD) and the presence or absence of precipitates were also measured. The results are shown in Tables 1 and 2.

While unrolling the roll of the laminate of the protective film and the transparent resin film of Example 4, the transparent resin film was introduced into a drying oven and further dried (main drying) while peeling off the protective film. The temperature of the drying furnace was 200° C., the conveying speed was 1.0 m/min, and the interval between drying was 12 minutes. The transparent resin film after drying in a drying oven was laminated on one surface with a protective film (Tretec 7332K manufactured by Toray Film Machinery Co., Ltd., a polyolefin protective film with weak adhesive strength) and wound on a roll core. When the protective film was peeled off and the amount of residual solvent in the transparent resin film after the main drying was measured, it was 0.6%. The transparent resin film obtained by this drying can also be used as a window film base material.

Comparative Example 1
Thickness 198 μm (PET 188 μm with double-sided easy adhesion layer+hard coat layer 5 μm), width 1300 mm, cast film forming surface side (that is, hard coat layer surface side) Martens hardness 410 N/mm, non-hard coat side Martens hardness 268 N/ A polyethylene terephthalate (PET) film support having a long hard coat layer of mm (support E: base resin=PET, with one-sided HC treatment) was applied by a cast method with a width of 1200 mm to form a film. A transparent resin film was formed in the same manner as in Example 3.

When a peeling test was performed on the laminated body obtained in Comparative Example 1, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm, and 20 mm by 180°.

The support was peeled off while unwinding the rolled-up laminated body, and the laminated body composed of the transparent resin film and the protective film was wound up. By the same method as in Example 1, the evaluation of scratches, haze, total light transmittance, yellow index and residual solvent amount of the support and the transparent resin film from which the protective film was peeled off were evaluated. Regarding the support, the Martens hardness (cast surface/non-cast surface), arithmetic mean roughness (Ra: cast surface/non-cast surface), maximum height (Rz: cast surface/non-cast surface), heat shrinkage ratio ( MD/TD) and the presence or absence of precipitates were also measured. The results are shown in Tables 1 and 2.

Reference example 1
Physical properties were also measured by the same treatment as in Example 3 except that a PET film having a Martens hardness of 268 N/mm (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.: base resin=PET, without HC treatment) was used as the support. did. The results are shown in Table 2. The cast film-forming surface of the support, that is, the Martens hardness measurement surface is the surface opposite to the easily slippery surface of the PET film.

When a peeling test was performed on the laminate obtained in Comparative Example 2, peeling did not occur in all cases when it was wound around each cylindrical rod having a diameter of 100 mm, 80 mm, 60 mm, 40 mm and 20 mm by 180°.

The support was peeled off while unwinding the rolled-up laminated body, and the laminated body composed of the transparent resin film and the protective film was wound up. By the same method as in Example 1, the evaluation of scratches, haze, total light transmittance, yellow index and residual solvent amount of the support and the transparent resin film from which the protective film was peeled off were evaluated. The results are shown in Table 1.

The laminate of the present invention is used during the production of a transparent resin film and reduces various defects that occur during the production, which improves the yield and leads to a reduction in the production cost.

DESCRIPTION OF SYMBOLS 1... Support body 2... Transparent resin film 3... Protective film 10... Support roll 11... Guide roll 12... Coating process 13... Pre-drying process 14... Protective film roll 15... Three-layer winding roll

Claims (14)

A support having a first surface and a second surface, a first hard coat layer formed on the first surface of the support, and a transparent layer releasably laminated on the first hard coat layer. A laminate comprising a resin film layer and a second hard coat layer formed on a second surface of the support opposite to the first surface. The laminate according to claim 1, wherein the adhesive force between the first hard coat layer and the transparent resin film layer is 0.02 N/10 mm or more. The laminate according to claim 1, wherein the support is a resin film. The support is any one of a polyethylene terephthalate film having a hard coat layer on both sides, a cycloolefin film, an acrylic film, a polyethylene naphthalate film, a polypropylene film, and a triacetyl cellulose film. The laminate described. The laminate according to any one of claims 1 to 4, wherein the support has an arithmetic mean roughness (Ra) of 0.01 µm or less defined in JIS B0601-2001 on the surface of the first hard coat layer. The laminate according to any one of claims 1 to 5, wherein the first-stage support has a maximum height (Rz) defined in JIS B0601-2001 of the surface of the first hard coat layer of 0.1 µm or less. The said transparent resin film is a polyimide film, The laminated body in any one of Claims 1-6. The laminate according to claim 1, wherein the transparent resin film is a polyimide film having a haze of 1% or less, a total light transmittance of 85% or more, and a yellow index of 4 or less. A laminate film roll obtained by winding the laminate according to any one of claims 1 to 8. a) A resin varnish obtained by mixing and stirring a resin composition for forming a transparent resin film with a solvent, which has a first surface and a second surface and is on both the first surface and the second surface. A step of applying to the surface of the first hard coat layer formed on the first surface of the support having a hard coat layer provided thereon; and b) removing the solvent by drying the applied resin varnish, Forming a transparent resin film layer on the first hard coat layer;
The method for manufacturing a laminated body according to claim 1, comprising: A window film substrate obtained by further subjecting the transparent resin film obtained by peeling from the laminate according to any one of claims 1 to 8 to solvent drying treatment. A window film comprising a window hard coat layer on at least one surface of the window film substrate according to claim 11. It is an optical laminated body containing the window film of Claim 12, Comprising: On one surface of the said window film, the optical laminated body which further has a polarizing plate. The optical laminate according to claim 13, further comprising a touch sensor on one surface of the window film.