JP2020006682A - Laminate - Google Patents

Abstract

To provide a laminate including a transparent resin film derived from a polyimide-based polymer, which hardly causes whitening on a film surface and has a good appearance and visibility.SOLUTION: A laminate comprises: a transparent resin film that comprises at least one polyamide imide and one or more solvents and that is produced by a casting method; and a protective film bonded to at least one surface of the transparent resin film. A boiling point of a solvent that has the highest boiling point in the solvents is 120 to 300°C; a residual solvent amount S (mass%) of the transparent resin film calculated from a thermogravimetry-differential thermal measurement, and a low molecular weight component amount W (mass%) of the protective film measured by gel permeation chromatography at a measurement temperature of 140°C satisfy a relational expression (1) S×W≤4.7; and S is 0.01 mass% or more and W is 1% or less.SELECTED DRAWING: None

Description

  The present invention relates to a laminate.

  In recent years, as the displays of various image display devices have become thinner, lighter, more flexible, and the like, a transparent resin film based on a polymer such as polyimide or polyamide has been widely used as a material that replaces conventionally used glass. . A casting method (solution dripping method) is known as one of the methods for producing such a transparent resin film. In the casting method, generally, a varnish containing a polymer such as polyimide dissolved in a solvent is coated on a supporting substrate to form a film, and after the coating is peeled off from the supporting substrate, the solvent is removed by drying to remove the resin. The film can be formed continuously. A protective film that can be peeled off is appropriately laminated on the surface of the formed transparent resin film to protect the film surface (Patent Documents 1 to 3).

JP 2010-208312 A JP 2015-214122 A JP-A-2006-87799

  When a solvent is present in the resin film, components such as additives contained in the protective film may be eluted into the solvent contained in the resin film. May whiten. In particular, in a transparent resin film manufactured using a solvent by a casting method or the like, in continuous production, it is difficult to completely remove the solvent in the varnish, and a certain amount of the solvent often remains. When it is bonded to a protective film, whitening is likely to occur. Whitening in such a transparent resin film is not only an appearance defect for a transparent resin film requiring high transparency, but also causes a deterioration in visibility when used for displays such as various image display devices. Become.

  Therefore, an object of the present invention is to provide a laminate including a transparent resin film based on a polyimide-based polymer, which is less likely to cause whitening of the film surface and has good appearance and visibility.

〔式（１０）中、Gは４価の有機基を表し、Ａは２価の有機基を表す〕
で表される繰り返し構造単位と、式（１１）〜（１３）：

〔式（１１）〜（１３）中、
Ｇ^１は４価の有機基を表し、Ｇ^２は３価の有機基を表し、Ｇ^３は２価の有機基を表し、
Ａ^１、Ａ^２およびＡ^３は、それぞれ独立に、２価の有機基を表す〕
のいずれかで表される繰り返し構造単位のいずれか１つ以上を含む重合体である、積層体。
［２］ＳとＷとが関係式（１’）：
０．００５≦ Ｓ × Ｗ （１’）
を満たす、前記［１］に記載の積層体。
［３］透明樹脂フィルムのヘイズが１．０％以下である、前記［１］または［２］に記載の積層体。
［４］透明樹脂フィルムの全光線透過率が８５％以上である、前記［１］〜［３］のいずれかに記載の積層体。
［５］透明樹脂フィルムが、Ｎ，Ｎ−ジメチルアセトアミド、γ−ブチロラクトン、Ｎ−メチルピロリドン、シクロペンタノン、酢酸ブチルおよび酢酸アミルからなる群から選択される溶媒を少なくとも１つ含む、前記［１］〜［４］のいずれかに記載の積層体。
［６］保護フィルムが、ポリオレフィン系樹脂フィルムである、前記［１］〜［５］のいずれかに記載の積層体。 The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides the following preferred embodiments.
[1] A transparent resin film comprising at least one kind of polyamideimide and one or more kinds of solvents and produced by a casting method using the one or more kinds of solvents, and at least one surface of the transparent resin film A laminate comprising a bonded protective film and
The boiling point of the solvent having the highest boiling point among the one or more solvents is 120 to 300 ° C,
The residual solvent amount S (% by mass) of the transparent resin film, which is calculated as a weight loss rate from 120 ° C. to 250 ° C. by thermogravimetric-differential heat (TD-DTA) measurement, and a measurement temperature of 140 ° C. of the protective film The low molecular weight component W (%), defined as the ratio of the area where Log M is from 2.82 to 3.32 with respect to the total area of the chart obtained by gel permeation chromatography in :
S × W ≦ 4.7 (1)
The filling,
S is 0.01% by mass or more, W is 1% or less,
The polyamideimide has the formula (10):

[In the formula (10), G represents a tetravalent organic group, and A represents a divalent organic group.]
And a repeating structural unit represented by the following formulas (11) to (13):

[In formulas (11) to (13),
G ¹ represents a tetravalent organic group, G ² represents a trivalent organic group, G ³ represents a divalent organic group,
A ¹ , A ² and A ³ each independently represent a divalent organic group]
The laminate which is a polymer containing any one or more of the repeating structural units represented by any one of the above.
[2] S and W are related equations (1 ′):
0.005 ≦ S × W (1 ′)
The laminate according to the above [1], which satisfies the following.
[3] The laminate according to the above [1] or [2], wherein the haze of the transparent resin film is 1.0% or less.
[4] The laminate according to any one of [1] to [3], wherein the transparent resin film has a total light transmittance of 85% or more.
[5] The aforementioned [1], wherein the transparent resin film contains at least one solvent selected from the group consisting of N, N-dimethylacetamide, γ-butyrolactone, N-methylpyrrolidone, cyclopentanone, butyl acetate and amyl acetate. ] The laminated body according to any one of [4].
[6] The laminate according to any one of [1] to [5], wherein the protective film is a polyolefin-based resin film.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body containing the transparent resin film based on a polyimide-type polymer which has a favorable appearance and visibility which does not produce whitening of a film surface easily can be provided.

FIG. 1 shows TG-DTA measurement results of the transparent polyimide-based film produced in Example 1.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various changes can be made without departing from the spirit of the present invention.

  The laminate of the present invention includes a transparent resin film and a protective film bonded to at least one surface of the transparent resin film, and the transparent resin film constituting the laminate of the present invention includes polyimide and polyamide. And a resin composition containing at least one selected from the group consisting of polyimide, polyamide and polyamide-imide.

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

  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 contain two or more different types of repeating structural units represented by the formula (10). In addition, the polyimide-based polymer according to this embodiment is a repeating polymer represented by any one of formulas (11), (12), and (13) as long as various physical properties of the obtained transparent resin film are not impaired. Any one or more of the structural units may be included.

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

G and G ¹ each independently represent 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 this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. The G and ^{G 1,} equation (20), equation (21), equation (22), equation (23), equation (24), equation (25), equation (26), equation (27), formula (28 ) Or a group represented by the formula (29), and a tetravalent chain hydrocarbon group 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 (CH 3) -, - 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 specific examples include a phenylene group. Yellowness index of the transparent resin film obtained from the easily suppressed, as the G and ^{G 1,} preferably of formula (20), equation (21), equation (22), equation (23), equation (24), wherein And groups represented by formula (25), formula (26) or formula (27).

G ² is represents a trivalent organic radical, preferably a trivalent 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 this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms.
The G ^2, equation (20), equation (21), equation (22), equation (23), equation (24), equation (25), equation (26), equation (27), equation (28) or Examples thereof include a group in which one of the bonding hands of the group represented by the formula (29) is replaced by 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 of G.

G ³ represents a divalent organic group, and preferably represents a divalent 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 this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms.
As G ³ , 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 non-adjacent atoms are replaced by a hydrogen atom 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 of G.

A, A ¹ , A ² and A ³ each represent a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms. 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 represented by Formula (30), Formula (31), Formula (32), Formula (33), Formula (34), Formula (35), Formula (36), and Formula (36). (37) or a group represented by the formula (38); a group in which these are substituted with at least one of a methyl group, a fluoro group, a chloro group and a trifluoromethyl group; and a chain hydrocarbon group having a carbon number of 6 or less. 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 -, - represents a CO- or -NR ^2. Here, R ² represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Here, R ² represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom. It is preferred that Z ¹ and Z ² and Z ² and Z ³ are each located at the meta or para position with respect to each ring.

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

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

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

  Specific examples of the aromatic tetracarboxylic dianhydride include a non-condensed polycyclic aromatic tetracarboxylic dianhydride, a monocyclic aromatic tetracarboxylic dianhydride and a condensed polycyclic aromatic tetracarboxylic acid. Carboxylic dianhydrides are mentioned. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 2,2 ′ , 3,3′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic 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 dianhydride (referred to as 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-phenylenedioxy) diphthalic dianhydride, and 4,4'-(m-phenylenedioxy) diphthalic dianhydride. Further, as the monocyclic aromatic tetracarboxylic dianhydride, 1,2,4,5-benzenetetracarboxylic dianhydride is used, and as the condensed polycyclic aromatic tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride is exemplified.

  Of these, 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, and 2,2', 3,3'-benzophenonetetracarboxylic dianhydride are preferred. 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 dianhydride (6FDA), 1,2-bis (2,3-dicarboxyphenyl) Nyl) 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-phenylenedioxy) diphthalic dianhydride and 4,4 ′-(m-phenylenedioxy) diphthalic dianhydride; more preferably 4,4′-oxydiphthalic dianhydride; 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride ( 6FD ), Bis (3,4-carboxyphenyl) methane dianhydride, and 4, 4 '- (p-phenylene-oxy) diphthalic acid dianhydride. These can be used alone or in combination of two or more.

  Examples of the aliphatic tetracarboxylic dianhydride include cyclic and acyclic aliphatic tetracarboxylic dianhydrides. The cycloaliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride. , Cycloalkanetetracarboxylic dianhydride such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic 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 dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and 1,2,3,4-pentanetetracarboxylic dianhydride. These can be used alone or in combination of two or more. Further, a cycloaliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride may be used in combination.

  Among the tetracarboxylic acid compounds, from the viewpoint of easily improving the elastic modulus, bending resistance, and optical properties of the transparent resin film, preferably the alicyclic tetracarboxylic dianhydride or the non-condensed polycyclic aromatic tetracarbonate Carboxylic dianhydrides are mentioned. 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 dianhydride (6FDA). These can be used alone or in combination of two or more.

  Polyimide-based polymer according to the present embodiment, in addition to the anhydride of tetracarboxylic acid used in the above polyimide synthesis, tetracarboxylic acid, tricarboxylic acid compound, as long as the various physical properties of the obtained transparent resin film are not impaired. Dicarboxylic acid compounds, their anhydrides, and their derivatives may be further reacted.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and related acid chloride compounds and acid anhydrides, and two or more of these may be used in combination. Specific examples thereof include an anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; a single bond of phthalic anhydride and benzoic acid; _{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 related acid chloride compounds and acid anhydrides, and two or more of these may be used in combination. Specific examples thereof include dicarboxylic acid compounds of terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; and a chain hydrocarbon having 8 or less carbon atoms; two benzoate skeleton _{-CH 2 -, - S -,} - C (CH 3) 2 -, - C (CF 3) 2 -, - O -, - NR 9 -, - C (= O) -, A compound linked by —SO ₂ — or a phenylene group is exemplified. 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 two benzoic acid skeletons having —CH ₂ —, —C (＝ O). —, —O—, —NR ⁹ —, —SO ₂ — or a compound linked by a phenylene group, more preferably terephthalic acid; 4,4′-biphenyldicarboxylic acid; and two benzoic acid skeletons— ^{O -, - NR 9 -,} - C (= O) - or -SO ₂ - is a compound linked with. 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, tricarboxylic acid compound and dicarboxylic acid compound is preferably at least 40 mol%, more preferably at least 50 mol%, further preferably at least 70 mol%. And more preferably at least 90 mol%, particularly preferably at least 98 mol%.

  Examples of the diamine used for the synthesis of the polyimide polymer include an aliphatic diamine, an aromatic diamine, and a mixture thereof. In the present embodiment, “aromatic diamine” refers to a diamine in which an amino group is directly bonded to an aromatic ring, and a part of the structure may include an aliphatic group or another substituent. The aromatic ring may be a single ring or a condensed ring, and is exemplified by, but not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring. Among these, a benzene ring is preferred. The “aliphatic diamine” refers to a diamine in which an amino group is directly bonded to an aliphatic group, and may have an aromatic ring or another substituent in a part of its structure.

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

  Specific examples of the aromatic diamine 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'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, bis [4- (4-aminophen) Noxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-amino Phenoxy) phenyl] propane, 2,2′-dimethylbenzidine, 2,2′-bis (trifluoromethyl) -4,4′-diaminodiphenyl (sometimes referred to as TFMB), 4,4′-bis ( 4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9,9-bis (4-amino-3-chlorophenyl) ) Aromatic diamines having two or more aromatic rings, such as fluorene and 9,9-bis (4-amino-3-fluorophenyl) fluorene. These can be used alone or in combination of two or more.

  As the aromatic diamine, preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylether, 3,3'-diaminodiphenylether, 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), 4,4′-bis (4 Aminophenoxy) biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylsulfone, 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) and 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 viewpoint 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. And at least one selected from the group consisting of 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (TFMB) and 4,4'-bis (4-aminophenoxy) biphenyl. preferable. A diamine having a biphenyl structure and a fluorine-based substituent is more preferable, and as a specific example, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (TFMB) is more preferably used.

  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 dianhydride). 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 anhydrides) and dicarboxylic acid compounds (including derivatives such as acid chloride compounds) may be used as starting materials. is there. Further, 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 the formulas (10) and (11) are usually derived from diamines and tetracarboxylic acid compounds. The repeating structural unit represented by the formula (12) is usually derived from a diamine and a tricarboxylic acid compound. The repeating structural unit represented by the formula (13) is usually derived from a diamine and a dicarboxylic acid compound. Specific examples of the diamine, tetracarboxylic acid compound, tricarboxylic acid compound and dicarboxylic acid compound are as described above.

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

  Further, from the viewpoint of suppressing the yellowness of the obtained transparent resin film, it is preferable that the ratio of the amino group occupying the obtained polymer terminal is low, and a carboxylic acid compound such as a tetracarboxylic acid compound is used for 1.00 mol of the diamine. It is preferably at least 1.00 mol.

  By adjusting the number of fluorine atoms in the molecules of the diamine and carboxylic acid compound (eg, tetracarboxylic acid compound), the amount of fluorine in the obtained polyimide-based polymer is adjusted to 1% by mass or more based on the mass of the polyimide-based polymer. , 5% by mass or more, 10% by mass or more, and 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 on either the diamine or the carboxylic acid compound, or may be present on both. By including a fluorine-based substituent, the YI value may be particularly reduced.

  The polyimide-based polymer according to the present embodiment may be a copolymer including a plurality of the above-described repeating structural units of different types. The weight average molecular weight of the polyimide polymer in terms of standard polystyrene is usually from 100,000 to 800,000. When the weight average molecular weight of the polyimide-based polymer is large, the flexibility at the time of forming a film is improved, so that it is preferably 200,000 or more, more preferably 300,000 or more, and still more preferably 350,000. That is all. In addition, since a varnish having an appropriate concentration and viscosity is obtained and the film-forming property tends to be improved, it is preferably 750,000 or less, more preferably 600,000 or less, and further preferably 500,000. It is as follows.

  By containing a fluorine-containing substituent, polyimide-based polymers and polyamides tend to have an improved elastic modulus when formed into a film and a reduced YI value. When the elastic modulus of the film is high, generation of scratches and wrinkles tends to be suppressed. From the viewpoint of the transparency of the film, the polyimide 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 polymer and the polyimide polymer and the polyamide, respectively, based on the mass of the polyimide polymer or the sum of the mass of the polyimide polymer and the mass of the polyamide, preferably It is from 1% by mass to 40% by mass, more preferably from 5% by mass to 40% by mass. When the content of the fluorine atom is 1% by mass or more, the YI value at the time of forming a film tends to be further reduced and the transparency can be further improved. When the content of the fluorine atom is within 40% by mass, it tends to be easy 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 forming the transparent resin film is preferably at least 40% by mass, more preferably at least 50% by mass, based on the solid content of the resin composition. And more preferably 70% by mass or more, and may be 100% by mass. When the content of the polyimide-based polymer and / or the polyamide is not less than the above lower limit, the flexibility of the transparent resin film is good. The solid content refers to the total amount of the 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 above-mentioned polyimide-based polymer and / or polyamide. Examples of the inorganic material include silica particles, titanium particles, aluminum hydroxide, zirconia particles, inorganic particles such as barium titanate particles, and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate. From the viewpoint of the dispersibility of the inorganic material, preferably, silica particles, aluminum hydroxide, and zirconia particles are used, and more preferably, silica particles are used.

  The average primary particle diameter of the inorganic material is preferably 1 to 200 nm, more preferably 3 to 100 nm, further preferably 5 to 50 nm, and still more preferably 5 to 30 nm. When the average primary particle size is 100 nm or less, transparency tends to be improved. If the average primary particle diameter is 10 nm or more, the cohesive force of the inorganic material is weakened, so that the handling tends to be easy.

  In the present invention, the silica particles may be a silica sol obtained by dispersing silica particles in an organic solvent or the like, or a silica fine particle powder produced by a gas phase method may be used. Preferably, the silica sol is produced.

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

  In the present invention, the content of the inorganic material in the resin composition is preferably from 0% by mass to 90% by mass based on the solid content of the resin composition. More preferably, it is 10% by mass or more and 60% by mass or less, and still more preferably 20% by mass or more and 50% by mass or less. When the content of the inorganic material in the resin composition is within the above range, the transparency and mechanical strength of the transparent resin film tend to be easily compatible. The solid content refers to the total amount of the 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-based polymer and other components other than the inorganic material, the content of the other components is 0% or more and 20% by mass or more with respect to the total mass of the transparent resin film. Is preferably not more than 0%, and more preferably not less than 0% and not more than 10% by mass.

  In the present invention, the transparent resin film is, for example, a reaction solution of a polyimide-based polymer and / or a polyamide obtained by reacting by selecting from the tetracarboxylic acid compound, the diamine and the other raw materials, 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 or the resin varnish, a solution of a purchased polyimide-based polymer or the like or a solution of a purchased solid polyimide-based polymer or the like may be used instead of the reaction solution of the polyimide-based polymer or the like.

  As a solvent that can be used for preparing the resin varnish, a solvent that can dissolve or disperse a resin component such as a polyimide-based polymer can be appropriately selected. 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 the solvent so that the boiling point of the solvent having the highest boiling point among the solvents used falls within the above range. From the viewpoints of solubility of the resin component, coatability, drying property, and the like, an organic solvent having a boiling point of 120 to 300 ° C is preferable, more preferably 120 to 270 ° C, further preferably 120 to 250 ° C, and particularly preferably 120 to 250 ° C. Organic solvents having a boiling point of ２３０230 ° C. are preferred. Specific examples of such organic solvents 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 solvents such as butyl acetate and amyl acetate; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane; and carbonate solvents such as ethylene carbonate and propylene carbonate. And the like. Among them, N, N-dimethylacetamide (boiling point: 165 ° C), γ-butyrolactone (boiling point: 204 ° C), N-methylpyrrolidone (boiling point: 202 ° C), because of its excellent solubility in polyimide polymers and polyamides, A solvent selected from the group consisting of cyclopentanone (boiling point: 131 ° C.), butyl acetate (boiling point: 126 ° C.), and amyl acetate (boiling point: 149 ° C.) is preferred.

  The amount of the solvent may be selected so as to have a viscosity at which the resin varnish can be handled, and is not particularly limited. For example, the amount is preferably 50 to 95% by mass, more preferably 70 to 95% by mass relative to the total amount of the resin varnish. %, More preferably 80 to 95% by mass.

  Further, the content of the solvent in the transparent resin film constituting the laminate of the present invention is determined by a residual solvent amount S (% by mass) calculated as a mass reduction ratio from 120 ° C. to 250 ° C. by thermogravimetry-differential thermal measurement. It must be within a range that satisfies a predetermined relationship with respect to the low molecular component amount W (%) in the protective film described later. In the present invention, the amount S of the residual solvent in the transparent resin film may be appropriately adjusted in relation to the amount W of the low molecular component in the protective film to be bonded, but is preferably 20% by mass or less, more preferably It is at most 17% by mass, more preferably at most 15% by mass. When the residual solvent amount S is equal to or less than the upper limit, the obtained transparent resin film can be formed as a self-standing film. Although the lower limit of the residual solvent amount S is not particularly limited, in the production of a transparent resin film containing a polyimide polymer or a polyamide as a resin component, the boiling point generally exceeds 100 ° C. as described above. Is used, it is difficult to completely remove the solvent during the production process, and usually it is 0.001% by mass or more. From the viewpoint of flexibility, the content is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, and still more preferably 0.5% by mass or more. .

In the present invention, the residual solvent amount S is measured using a thermogravimetric-differential heat (TG-DTA) measuring device, and a transparent resin film (sample) to be measured is heated at a rate of 10 ° C./min from room temperature to 120 ° C. The temperature change was measured at a heating rate of 120 ° C., the adsorbed water was removed by maintaining the temperature at 120 ° C. for 5 minutes, and the mass change measured while heating (heating) at a rate of 10 ° C./min to 400 ° C. Is a value obtained by calculating the mass reduction rate S (mass%) from 120 ° C. to 250 ° C. according to the relational expression (2).
S (% by mass) = 100− (W1 / W0) × 100 (2)
[In the formula (2), 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 measured by the thermogravimetric-differential calorimeter].

  The amount S of the residual solvent is determined by adjusting the amount of the solvent contained in the resin varnish for forming the transparent resin film, the type of the solvent, and the drying conditions (drying temperature and time, wind speed, etc.) of the coating film formed from the resin varnish. Can be controlled.

  The thickness of the transparent resin film may be appropriately determined according to the use of the transparent resin film, etc., and is usually 10 to 500 μm, preferably 15 to 200 μm, and more preferably 20 to 100 μm. When the thickness of the transparent resin film is within the above range, the flexibility of the transparent resin film is good.

  The laminate of the present invention includes a protective film attached to the transparent resin film. The protective film may be bonded to only one surface of the transparent resin film, or may be bonded to both surfaces. The protective film bonded to the transparent resin film is usually 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. It is preferable to be selected from the group consisting of polyolefin resin films such as polyethylene, polypropylene films and the like. When protective films are stuck on both surfaces of the transparent resin film, the protective films on each surface may be the same or different.

  In the laminate of the present invention, the protective film is a substrate film and laminated thereon, for example, an acrylic pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a pressure-sensitive adhesive layer formed from a silicone-based pressure-sensitive adhesive and the like. However, from the viewpoint of minimizing contamination on the surface of the transparent resin film, a resin film having self-adhesiveness, such as a polyolefin resin, is preferable.

  Further, the whitening of the transparent resin film, which is the subject of the present invention, is that a low molecular component contained in the protective film is eluted in a solvent used for producing a transparent resin film containing a polyimide polymer and a polyamide as a resin component. It is thought that it occurs by doing. Among protective films generally used in the field of laminates, polyolefin-based resin films tend to contain relatively large amounts of low-molecular components, so the effect of the present invention of suppressing whitening of a transparent resin film is protected. It is particularly advantageously obtained in a laminate using a polyolefin resin film as the film. Therefore, in a preferred embodiment of the present invention, the protective film used in the laminate of the present invention is a polyolefin resin film, and is easily available and inexpensive, and is more preferably a polypropylene resin film or a polyethylene resin. Film, and more preferably a polyethylene resin film. Examples of the polyethylene resin include high-pressure low-density polyethylene (LDPE), linear short-chain branched polyethylene (LLDPE), medium-low pressure high-density polyethylene (HDPE), and ultra-low-density polyethylene (VLDPE). However, the resin on the surface adjacent to the transparent resin film is preferably LLDPE from the viewpoint of adhesiveness to the transparent resin film and workability. In addition, when the protective films are bonded on both surfaces of the transparent resin film, the protective films on each surface may be the same as each other or may be different, but the protective films bonded on at least one surface. Is preferably a polyolefin-based resin film.

Here, in the present invention, the “low-molecular component” contained in the protective film is defined as having a Log M of 2.82 to 3.80 on a chart obtained by gel permeation chromatography at a measurement temperature of 140 ° C. under the following conditions. Means components detected in the range up to 32.
<Measurement conditions for gel permeation chromatography>
Column: One PLgel Individual (5 μm, 50 mm, 7.5 mm ID × 30 cm, manufactured by Agilent Technologies) and two TSKgel GMH _HR- H (S) HT (7.5 mm ID × 30 cm, manufactured by Tosoh Corporation) Connected mobile phase: Ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) with BHT (di-tert-butylhydroxytoluene) added at 0.1 w / V% Flow rate: 1 mL / min Column oven temperature: 140 ° C
Autosampler temperature: 140 ° C
System oven temperature: 40 ° C
Detection: Differential refractive index detector (RID)
RID cell temperature: 140 ° C
Sample solution injection volume: 300 μL
Standard substance solution for GPC column calibration: Standard polystyrene manufactured by Tosoh Corporation More detailed measurement conditions of gel permeation chromatography are described in Examples described later.

  The low-molecular component is, specifically, in the protective film, or when the protective film is composed of a base film and an adhesive layer laminated thereon, the remaining monomers and oligomers contained in the adhesive layer It is considered to be a component derived from additives and film raw materials. Examples of the low molecular components contained in the protective film include a nucleating agent, an antioxidant, a hydrochloric acid absorber, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antiblocking agent, an antistatic agent, a flame retardant, and a pigment. Components derived from dyes, dispersants, copper damage inhibitors, neutralizers, foaming agents, plasticizers, foam inhibitors, crosslinkers, flow improvers such as peroxides, weld strength improvers, etc. are protected. Examples of the low molecular component contained in the pressure-sensitive adhesive layer laminated on the film include components derived from a tackifier resin, a softener, and the like.

  In the present invention, the content of the low molecular component contained in the protective film is determined according to the measurement conditions of the gel permeation chromatography described above, and Log M with respect to the entire area of a chart obtained by gel permeation chromatography at a measurement temperature of 140 ° C. A range in which the amount of low molecular components W (%) defined as the ratio of the area from 2.82 to 3.32 satisfies a predetermined relationship with the amount of residual solvent S (% by mass) in the transparent resin film described later. Must be. In the present invention, the amount W of low molecular components in the protective film may be appropriately adjusted in relation to the amount S of residual solvent in the transparent resin film to be bonded, but is preferably 1% or less, more preferably 0% or less. 0.8% or less, more preferably 0.5% or less, particularly preferably 0.33% or less. When the amount W of the low-molecular component is equal to or less than the above upper limit, the transfer of the low-molecular component contained in the protective film to the transparent resin film becomes difficult to occur, which is suitable as a protective film for protecting the transparent resin film surface for optics. It is. Although the lower limit of the low molecular component amount W is not particularly limited, the protective film used in the field of the optical laminate generally includes a low molecular component derived from the additives and raw materials exemplified above. Therefore, the content is usually 0.00001% or more, preferably 0.001% or more, more preferably 0.01% or more, and further preferably 0.02% or more.

  The thickness of the protective film is not particularly limited, but is usually 10 μm or more, preferably 20 μm or more, and more preferably 25 μm or more from the viewpoint of protection of the transparent resin film. On the other hand, the thickness is preferably 300 μm or less from the viewpoint of film handling. When a protective film is stuck on both surfaces of the transparent resin film, the thickness of the protective film on each surface may be the same or different.

In the present invention, the residual solvent amount S (% by mass) of the transparent resin film constituting the laminate and the low molecular component amount W (%) of the protective film bonded to the transparent resin film are represented by a relational expression (1). ):
S × W ≦ 4.7 (1)
The transparent resin film and the protective film are combined so as to satisfy the following. From the viewpoint of the whitening suppression effect, the value of S × W (hereinafter, also referred to as “value of formula (1)”) in the laminate of the present invention is preferably 4.5 or less, more preferably 4.0. Or less, more preferably 3.5 or less, even more preferably 3.4 or less, particularly preferably 3.3 or less, still more preferably 2.0 or less, and particularly preferably 0 or less. 0.5 or less, particularly preferably 0.4 or less.
Further, S and W are expressed by the relational expression (1 ′):
0.005 ≦ S × W (1 ′)
Preferably, the transparent film and the protective film are combined so as to satisfy the following. The value of S × W (hereinafter also referred to as “value of formula (1 ′)) in the laminate of the present invention is preferably 0.007 or more.
When the protective films are bonded to both surfaces of the transparent resin film, the low molecular weight component W of each protective film is related to the residual solvent content S of the transparent resin film by the above formulas (1) and (1). ') Is preferred.

  When the value of the formula (1) is such that a transparent resin film having a large amount of residual solvent is used, a protective film having a low molecular weight is selected. It can be controlled by selecting a transparent resin film having a small residual solvent amount.

  The laminate of the present invention is excellent in the effect of suppressing the whitening of the surface of the transparent resin film to which the protective film is bonded by controlling the amount of the residual solvent in the transparent resin film and the amount of the low molecular component of the protective film. Therefore, the transparent resin film constituting the laminate of the present invention has excellent transparency, and the haze thereof is preferably 1.0% or less, more preferably 0.7% or less, and further preferably 0.1% or less. 5% or less. Moreover, the total light transmittance of the transparent resin film constituting the laminate of the present invention is preferably 85% or more, more preferably 87% or more, and further preferably 90% or more. Further, the yellowness of the transparent resin film constituting the laminate of the present invention is preferably 3.0 or less, more preferably 2.5 or less, and further preferably 2.2 or less. When the haze and the total light transmittance of the transparent resin film constituting the laminate are in the above ranges, the laminate is suitable for optical applications requiring high transparency. In addition, the laminate of the present invention is suitable for optical applications because the transparent resin film has low yellowness and suppressed coloring. The “whitening of the transparent resin film” in the present invention can be identified by irradiating a high-luminance light having a luminous flux of 3,000 lumens, as described in Examples described later. It does not necessarily directly affect haze and total light transmittance of the resin film. The transparent resin film used by peeling the protective film from the laminate of the present invention is less likely to cause whitening of the film surface and is excellent in transparency, so if the transparent resin film is used, for example, a resin film having a low transmittance may be used. As compared with the case where the light emitting element is used, it is easier to secure a constant brightness, and the light emission intensity of the display element or the like can be suppressed. Therefore, power consumption can be reduced.

The laminate of the present invention can be produced by laminating a transparent resin film and a protective film using a known method and apparatus / equipment. Specifically, for example,
Applying a resin varnish obtained by mixing and stirring a resin composition for forming a transparent resin film with a solvent on a supporting substrate;
Removing the solvent by drying the applied resin varnish to form a transparent resin film layer on the supporting substrate;
Laminating a protective film on the surface of the transparent resin film formed on the support substrate opposite to the support substrate; and peeling the support substrate from the transparent resin film layer formed on the support substrate Can be produced by a method including

  For example, as typified by a casting method, when a resin varnish containing a solvent is applied to form a film and then a transparent resin film is continuously produced by a method including a step of removing the solvent by drying, the solvent is dried. Is difficult to completely remove, and it is often used in the next step with the solvent remaining in the transparent resin film, and whitening tends to occur when the protective film is bonded. Even in such a case, by selecting the protective film so as to satisfy the relationship of the above formula (1) according to the amount of the residual solvent in the transparent resin film, and according to the amount of the low molecular component of the protective film to be used. By controlling the drying conditions of the transparent resin film so as to satisfy the relationship of the above formula (1), it is possible to easily and effectively suppress whitening occurring on the surface of the transparent resin film to which the protective film is attached. . Further, it is preferable that the above formula (1 ') is satisfied.

  When the laminate of the present invention is produced by the above method, the supporting substrate on which the resin varnish is applied is a film-like substrate, and for example, even if it is a resin film substrate or a steel substrate (for example, a SUS belt). Good. Examples of the resin film base include a polyethylene terephthalate (PET) film. The thickness of the supporting substrate is not particularly limited, and is, for example, 10 to 500 μm, and preferably 50 to 300 μm.

  In the drying step of the coating film, it is preferable to remove the solvent by drying so that the solvent in the resin varnish is in a desired range. Drying for removing the solvent may be performed by natural drying, ventilation drying, heat drying or drying under reduced pressure, and a combination thereof. From the viewpoint of production efficiency and the like, heating and drying are preferred. Drying conditions may be appropriately determined according to the type of solvent used, the content of the solvent in the film, and the like, as long as the optical characteristics of the transparent resin film are not impaired. For example, heating may be performed at a temperature of 50 to 300 ° C., preferably 70 to 250 ° C., for example, for about 5 to 100 minutes.

  Next, a protective film having a low molecular component amount that satisfies the relationship of the above formula (1) is attached to the surface of the transparent resin film opposite to the support substrate, and a layer of the transparent resin film is formed on the support substrate. Further, a laminated film in which a protective film is laminated on the transparent resin film layer is obtained. Thereafter, by peeling the supporting substrate from the layer of the transparent resin film, a laminated film in which the protective film is bonded to the transparent resin film can be obtained. If necessary, a protective film may be bonded to the surface of the transparent resin film from which the supporting substrate has been peeled off.

  The laminate of the present invention can suppress whitening on the surface of the transparent resin film to which the protective film is bonded, and has high transparency and good appearance, and is particularly used for optical applications such as displays of various image display devices. Can be suitably used.

  Hereinafter, the present invention will be described in more detail with reference to examples. "%" And "parts" in the examples are% by mass and parts by mass unless otherwise specified. The residual solvent content of the transparent resin film and the low molecular component content of the protective film used in Examples and Comparative Examples were measured and calculated according to the following methods, respectively.

<Method for measuring residual solvent amount S>
Thermogravimetric-differential heat (TG-DTA) measurement As a TG-DTA measuring device, TG / DTA6300 manufactured by Hitachi High-Tech Science was used. About 20 mg of a sample was obtained from the produced transparent polyimide-based film. This sample was heated from room temperature to 120 ° C. at a rate of 10 ° C./min, held at 120 ° C. for 5 minutes, and then heated (heated) to 400 ° C. at a rate of 10 ° C./min. And the mass change of the sample was measured. FIG. 1 shows a TG-DTA measurement result of a transparent polyimide film produced in Example 1 described later.

From the TG-DTA measurement results, the mass reduction rate S (% by mass) from 120 ° C. to 250 ° C. was calculated according to the relational expression (2).
S (% by mass) = 100− (W1 / W0) × 100 (2)
[In the formula (2), 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 a residual solvent amount S (% by mass) in the transparent resin film.

<Measurement method of low molecular components>
The amount of the low molecular component is determined by a gel permeation chromatography (GPC) method. GPC measurement is performed under the following conditions. The amount of the low molecular component is determined by a gel permeation chromatography (GPC) method. With respect to the obtained chromatogram, a chart was obtained in which the electric signal value (intensity Y) derived from the difference in the refractive index between the test target solution and the reference solution was plotted against the polystyrene equivalent molecular weight Log M. In this chart, a line connecting points of Log M of 2.82 and 7.61 was defined as a baseline. In addition, 0 was set for a portion where the intensity Y value corrected by the baseline was negative.
(1) Sample solution preparation conditions Solvent: Ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) added with BHT (di-tert-butylhydroxytoluene) at 0.1 w / V% Sample solution concentration: 1 mg / ML
Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation)
Dissolution conditions: A 5 mg sample was sealed in a SUS wire mesh bag of 1000 mesh, the wire mesh bag containing the sample was placed in a test tube, and then 5 mL of a solvent was added to the test tube. Next, the test tube covered with aluminum foil was set in DF-8020, and stirred at 140 ° C. for 120 minutes at a stirring speed of 60 reciprocations / minute.

(2) Measurement conditions (GPC equipment and software)
Measuring device: HLC-8121 GPC / HT (manufactured by Tosoh Corporation)
Measurement software: GPC-8020 model II data collection Version 4.32 (manufactured by Tosoh Corporation)
Analysis software: GPC-8020 model II data analysis Version 4.32 (manufactured by Tosoh Corporation)
(Measurement condition)
GPC column: One PLgel Individual (5 μm, 50 mm, 7.5 mm ID × 30 cm, manufactured by Agilent Technologies) and two TSKgel GMH _HR- H (S) HT (7.5 mm ID × 30 cm, manufactured by Tosoh Corporation) Mobile phase: Ortho-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) with BHT added at 0.1 w / V% Flow rate: 1 mL / min Column oven temperature: 140 ° C.
Autosampler temperature: 140 ° C
System oven temperature: 40 ° C
Detection: Differential refractive index detector (RID)
RID cell temperature: 140 ° C
Sample solution injection volume: 300 μL
GPC column calibration standard solution: Standard polystyrene manufactured by Tosoh Corporation was weighed as shown in the table below, 5 mL of orthodichlorobenzene (same composition as the mobile phase) was added, and completely dissolved at room temperature. Preparation

From the GPC measurement results, the amount of low molecular components W (%) was calculated by the relational expression (3).
W (%) = V0 / V1 (3)
[In the formula (3), V0 is the area of Log M in the chart obtained from GPC measurement from 2.82 to 3.32, and V1 is the area of the entire chart.]

<Method of measuring elastic modulus>
The transparent resin films obtained in Examples and Comparative Examples were dried at 200 ° C. for 20 minutes, and cut into 10 mm × 100 mm strips using a dumbbell cutter to obtain samples. The elastic modulus of this sample was measured using an Autograph AG-IS manufactured by Shimadzu Corporation under the conditions of a distance between chucks of 500 mm and a pulling speed of 20 mm / min. Calculated.

<Method of measuring total light transmittance>
The transparent resin films obtained in the examples and the comparative examples were cut into a size of 30 mm × 30 mm, and a haze computer (“HGM-2DP”, manufactured by Suga Test Instruments Co., Ltd.) was used at a thickness of 50 μm of the optical film. The total light transmittance (%) was measured.

<Method for measuring haze value>
The transparent resin films obtained in Examples and Comparative Examples were cut into a size of 30 mm × 30 mm, and the haze (%) was measured using a haze computer (“HGM-2DP” manufactured by Suga Test Instruments Co., Ltd.). .

<Method of measuring yellowness>
The transparent resin films obtained in Examples and Comparative Examples were cut into a size of 30 mm × 30 mm, and tristimulus values (V-670 manufactured by JASCO Corporation) were measured using an ultraviolet-visible-near-infrared spectrophotometer (V-670 manufactured by JASCO Corporation). X, Y, Z) were obtained and substituted into the calculation formula (4) to calculate the YI value.
YI = 100 × (1.2767X−1.0592Z) / Y (4)

Production Example 1: Preparation of Transparent Polyimide Polymer A reactor equipped with a silica gel tube, a stirrer, and a thermometer in a separable flask and an oil bath were prepared. In this flask, 75.52 g of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2′-bis (trifluoromethyl) -4,4′-diaminodiphenyl (TFMB) 54.44 g were charged. While stirring the mixture at 400 rpm, 519.84 g of N, N-dimethylacetamide (DMAc) was added, and stirring was continued until the contents of the flask became a uniform solution. Subsequently, stirring was continued for another 20 hours while adjusting the temperature in 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 temperature of the reaction system was returned to room temperature, and 649.8 g of DMAc was added to adjust the polymer concentration to 10% by weight. 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 to perform imidization. The polyimide varnish was taken out of the reaction vessel. The obtained polyimide varnish was dropped into methanol for reprecipitation, and the obtained powder was dried by heating to remove the solvent, thereby obtaining a transparent polyimide polymer as a solid content. GPC measurement of the obtained polyimide polymer showed a weight-average molecular weight of 360,000.

Production Example 2: Preparation of transparent polyamideimide polymer Under a nitrogen gas atmosphere, 50 g (156.13 mmol) of TFMB and 642.07 g of DMAc 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 the mixture was stirred at room temperature for 3 hours. Thereafter, 9.23 g (31.27 mmol) of 4,4′-oxybis (benzoyl chloride) (OBBC) and 15.87 g (78.18 mmol) of terephthaloyl chloride (TPC) were added to the flask, and the mixture was 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 the mixture was stirred at room temperature for 30 minutes, and then heated to 70 ° C. using an oil bath. The mixture was further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, poured into a large amount of methanol in the form of a thread, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and 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 polymer showed a weight average molecular weight of 420,000.

Production Example 3: Preparation of silica sol An amorphous silica sol having a BET diameter of 27 nm (average primary particle diameter measured by the BET method) prepared by a sol-gel method was used as a raw material, and γ-butyrolactone (hereinafter referred to as GBL) was obtained by solvent replacement. 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. Each of the obtained GBL-substituted silica sols contained 30 to 32% by mass of silica particles.

Example 1 Preparation of Laminate A resin varnish was prepared by dissolving the transparent polyimide-based polymer obtained in Production Example 1 at a concentration of 16.5% in a mixed solvent of GBL and DMAc mixed at a ratio of 1: 9. I got The obtained resin varnish was applied on a polyethylene terephthalate (PET) film substrate (188 μm thick, manufactured by Toyobo Co., Ltd. (product name: Cosmoshine (registered trademark) A4100)) by salivation molding to form a film. Thereafter, the coating film was dried by heating at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes, and the PET substrate was peeled from the coating film. Thereafter, by heating at 200 ° C. for 12 minutes, a transparent resin film having a thickness of about 80 μm was obtained. The amount of residual solvent in the obtained transparent resin-based film was 1% by mass. Further, the total light transmittance of the obtained transparent resin film was 92.5%, the haze was 0.3%, the yellowness was 2.1, and the elastic modulus was 4 GPa.
Next, Tretec (registered trademark) N-711 manufactured by Toray Film Processing Co., Ltd. was prepared as a protective film. The low molecular component content of the protective film was 0.33%. The resulting transparent resin film was bonded using a roller to produce a laminate.

<Evaluation of whitening>
The whitening of the obtained transparent resin film was confirmed.
The laminate produced in Example 1 was allowed to stand in an environment at a temperature of 23 ° C. and a humidity of 50% for 24 hours. Thereafter, the bonded protective film was peeled off, and the surface of the transparent resin film to which the protective film was bonded was rubbed with a clean waste cloth. Thereafter, the appearance (whitening) of the film was evaluated using a high-luminance light having a luminous flux of 3,000 lumens according to the following evaluation criteria. Table 2 shows the results.

<Evaluation criteria for whitening>
：: No whitening was observed ×: Whitening was observed on the surface of the transparent resin film

Example 2
The transparent polyimide-based polymer obtained in Production Example 1 was dissolved at a concentration of 16.5% in a mixed solvent of GBL and DMAc mixed at a ratio of 1: 9 to obtain a resin varnish. The obtained resin varnish was applied on a PET film substrate (188 μm thick, manufactured by Toyobo Co., Ltd. (product name: Cosmoshine A4100)) by salivation molding to form a film. Thereafter, the coating film was dried by heating at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes, and the PET substrate was peeled off from the coating film to obtain a transparent resin film having a thickness of 80 μm. The residual solvent amount of the obtained transparent resin film was 10% by mass. A laminate was obtained in the same manner as in Example 1 except that this was used as a transparent resin film.
The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 3
A laminate was obtained in the same manner as in Example 1 except that Tretec 7832C (manufactured by Toray Film Processing Co., Ltd., low molecular weight: 0.48%) was used as the protective film. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 4
A laminate was obtained in the same manner as in Example 2, except that Trefane BO 25-MK01 (manufactured by Toray Industries, Inc., low molecular weight: 0.04%) was used as the protective film. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 5
A laminate was obtained in the same manner as in Example 2, except that the transparent polyamideimide-based polymer obtained in Production Example 2 was dissolved at a concentration of 10% in a DMAc solvent to obtain a resin varnish. Was. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 6
The transparent polyamideimide-based 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 well to obtain a transparent composition having the composition shown in Table 2. A polyamide imide polymer / silica particle mixed varnish (hereinafter sometimes referred to as a mixed varnish) was obtained. At that time, a mixed varnish was prepared so that the concentration of the polyamideimide-based polymer / silica particles (the concentration based on the total mass of the resin and the silica particles) was 10% by mass. Then, the obtained mixed varnish was applied on a polyethylene terephthalate (PET) film base material (thickness: 188 μm, manufactured by Toyobo Co., Ltd. (product name: Cosmoshine A4100)) by salivation molding to form a film. Thereafter, the coating was dried by heating at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes, and the PET substrate was peeled off from the coating to obtain a transparent resin film having a thickness of 50 μm. The residual solvent amount of the obtained transparent resin film was 14% by mass. A laminate was obtained in the same manner as in Example 1 except that this was used as a transparent resin film. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 7
The transparent polyamideimide-based polymer obtained in Production Example 2 was dissolved in DMAc at a concentration of 12% to obtain a resin varnish. A laminate was obtained in the same manner as in Example 2, except that the drying conditions of the coating film were changed to heating at 70 ° C. for 30 minutes and heating at 140 ° C. for 15 minutes. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 8
After peeling the PET substrate from the coating film, a laminate was obtained in the same manner as in Example 1, except that the PET substrate was heated at 200 ° C. for 14 hours. The thickness of the obtained transparent resin-based film was 79 μm, and the amount of residual solvent was 0.024% by mass. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 1
A laminate was obtained in the same manner as in Example 2 except that Tretec 7832C (manufactured by Toray Film Processing Co., Ltd., low molecular weight: 0.48%) was used as the protective film. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 2
A laminate was obtained in the same manner as in Example 6, except that Tretec 7832C (manufactured by Toray Film Processing Co., Ltd., low molecular weight: 0.48%) was used as the protective film. The appearance (whitening) of the film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Claims (6)

A transparent resin film comprising at least one kind of polyamideimide and one or more kinds of solvents, produced by using the one or more kinds of solvents by a casting method, and bonded to at least one surface of the transparent resin film. And a protective film comprising:
The boiling point of the solvent having the highest boiling point among the one or more solvents is 120 to 300 ° C,
The residual solvent amount S (% by mass) of the transparent resin film, which is calculated as a mass reduction ratio from 120 ° C. to 250 ° C. by thermogravimetry-differential heat (TG-DTA) measurement, and a measurement temperature of 140 ° C. of the protective film The low molecular weight component W (%), defined as the ratio of the area where Log M is from 2.82 to 3.32 with respect to the total area of the chart obtained by gel permeation chromatography in :
S × W ≦ 4.7 (1)
The filling,
S is 0.01% by mass or more, W is 1% or less,
The polyamideimide has the formula (10):

[In the formula (10), G represents a tetravalent organic group, and A represents a divalent organic group.]
And a repeating structural unit represented by the following formulas (11) to (13):

[In formulas (11) to (13),
G ¹ represents a tetravalent organic group, G ² represents a trivalent organic group, G ³ represents a divalent organic group,
A ¹ , A ² and A ³ each independently represent a divalent organic group]
The laminate which is a polymer containing any one or more of the repeating structural units represented by any one of the above. S and W are related equations (1 ′):
0.005 ≦ S × W (1 ′)
The laminate according to claim 1, which satisfies the following.   The laminate according to claim 1 or 2, wherein the haze of the transparent resin film is 1.0% or less.   The laminate according to any one of claims 1 to 3, wherein the transparent resin film has a total light transmittance of 85% or more.   The transparent resin film according to claim 1, wherein the transparent resin film contains at least one solvent selected from the group consisting of N, N-dimethylacetamide, γ-butyrolactone, N-methylpyrrolidone, cyclopentanone, butyl acetate and amyl acetate. The laminate according to any one of the above.   The laminate according to any one of claims 1 to 5, wherein the protective film is a polyolefin-based resin film.

Images