TW202112542A - Laminate prevent peeling of the protective film or warping of the laminate from occurring in the laminate of the protective film and the transparent resin film - Google Patents

Abstract

An object of the present invention is to prevent peeling of the protective film or warping of the laminate from occurring in the laminate of the protective film and the transparent resin film. The present invention provides a laminate, comprising: a transparent resin film comprising at least one resin selected from the group consisting of polyimide, polyamide, and polyamide-imide; and a protective film bonded to one side of the transparent resin film. The laminate further comprises a layer at the other side of the transparent resin film, and the layer comprises a resin different from the resin contained in the transparent resin film; the tensile elastic modulus E1 and the thickness T1 of the laminate satisfy equations (1) 350 < E1×T1 < 1,000 (1), and the tensile elastic modulus E1 of the laminate and the tensile elastic modulus E2 of the protective film satisfy equation (2) 1.0 ≤ E1/E2 ≤ 6.5 (2).

Description

Layered body

The present invention relates to a laminate, and more particularly to a laminate containing a transparent resin film containing polyimide and the like, and a protective film for protecting the transparent resin film.

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 or polyamide have been widely used as an alternative to the previously used transparent resin films. The material of glass. Regarding the transparent resin film, a varnish containing a polymer such as polyimide is coated on the substrate, and then stretched and dried, and then a single-area protective film is applied to prevent the transparent resin film from being damaged. Furthermore, a functional layer, such as a hard coat layer, is formed on the other side of a transparent resin film with a protective film on a single area, and finally the protective film is peeled off and used for various purposes.

When the functional layer is formed on the other side from a single-area transparent resin film with a protective film, the composition of the functional layer is usually coated on the surface of the transparent resin film without a protective film, but protection will occur at this time. The peeling of the film or the warping of the laminate of the protective film and the transparent resin film.

Examples of documents describing a laminate of a transparent resin film and a protective film include Japanese Patent No. 6376271 (Patent Document 1), Japanese Patent No. 6450048 (Patent Document 2), and Japanese Patent No. 6400875 (Patent Document 3). There is no record related to the peeling of the protective film or the warpage of the laminate in the literature. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6376271 [Patent Document 2] Japanese Patent No. 6450048 [Patent Document 3] Japanese Patent No. 6400875

[The problem to be solved by the invention]

In the present invention, an object is to prevent peeling of the protective film or warping of the laminate in the laminate of the protective film and the transparent resin film. [Technical means to solve the problem]

The present invention provides the following aspects. [1] A laminated body comprising a transparent resin film and a protective film, the transparent resin film comprising at least 1 selected from the group consisting of polyimide, polyimide, and polyimide The above-mentioned protective film is attached to one side of the above-mentioned transparent resin film, and The tensile elastic modulus E1 and thickness T1 of the above-mentioned laminate satisfy the formula (1), 350＜E1×T1＜1,000 (1) And the tensile elastic modulus E1 of the above laminate and the tensile elastic modulus E2 of the protective film satisfy the formula (2) 1.0≦E1/E2≦6.5 (2). [2] The laminate as in [1], wherein the tensile modulus E1 of the laminate is 2.0 GPa or more and 10.0 GPa or less. [3] The laminate as in [1] or [2], wherein the tensile modulus E2 of the protective film is 1.5 GPa or more and 10.0 GPa or less. [4] The laminate according to any one of [1] to [3], wherein the total light transmittance of the transparent resin film with a thickness of 50 μm is 85.0% or more. [5] The laminated body as in [4], wherein the haze of the transparent resin film at a thickness of 50 μm is 1.0% or less. [6] The laminate according to any one of [1] to [5], wherein the protective film has an adhesive layer. [7] The laminate according to any one of [1] to [6], wherein the adhesive layer contains an acrylic resin. [8] The laminate according to any one of [1] to [7], wherein a transparent resin film is used for the front panel of the flexible device. [9] A laminated body with a functional layer, which is formed by an area layer functional layer on the side opposite to the surface of the protective film included in the laminated body as in any one of [1] to [7] . [10] The laminate with a functional layer as in [9], wherein the functional layer is a hard coat layer. [11] A protective film laminate, which is formed by laminating another protective film on the laminate with a functional layer such as [9] or [10]. [Effects of Invention]

In the present invention, when the laminate of the protective film and the transparent resin film meets the requirements of the present invention, that is, the tensile modulus E1 of the laminate itself and its thickness T1 satisfy the formula (1), 350＜E1×T1＜1,000 (1) And the tensile elastic modulus E1 of the laminate and the tensile elastic modulus E2 of the protective film satisfy the formula (2) 1.0≦E1/E2≦6.5 (2) At the same time, it can prevent the peeling of the protective film or the warping of the laminated body.

Theoretically, there is no particular limitation. It is preferable that the tensile elastic modulus E1 of the laminate is higher and the thickness T1 is also thicker, but there are limits to the height and thickness of the tensile elastic modulus, so it is necessary to make the tensile elastic modulus E1 The product with the thickness T1 falls within a specific range, and if it is within the range of 350<E1×T1<1,000 (1), the protective film will not peel off, and the warpage of the laminate falls within a good range. In addition, the tensile elastic modulus E1 of the laminate and the tensile elastic modulus E2 of the protective film are preferably the same. Therefore, it is considered that these values need to be within the range of 1.0≦E1/E2≦6.5.

In the present invention, if the characteristics of the laminate and the protective film are within the range of the above inequality, the protective film does not peel off, and the warpage of the laminate is also reduced, so that a functional layer such as a hard coat layer can be easily formed.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiments described here, and various changes can be made within a range that does not impair the gist of the present invention.

The laminated system of the present invention includes a transparent resin film and a protective film as layers. The transparent resin film includes at least one selected from the group consisting of polyimide, polyimide, and polyimide The protective film is attached to at least one side of the transparent resin film, and the laminated system uses the transparent resin film alone for various purposes or the laminated body of the transparent resin film and the functional layer is used for various purposes. For the laminated body produced in the intermediate stage, the diagrams are used to describe the steps of producing the laminated body.

FIG. 1 is a schematic cross-sectional view showing the layer structure in each step. The above steps are the steps from the formation of the transparent resin film to the state where the transparent resin film is covered by the functional layer. Step A of Figure 1 is the layer structure produced in the stage of coating a transparent resin film varnish on the substrate (metal or plastic film) to form a layer of the transparent resin film, and the next step B is to apply the transparent resin film 1 Perform the extension step of extension. In the next step C, the protective film 2 is formed on one side of the stretched transparent resin film 1, and then in step D, the functional layer 3 is formed on the side of the transparent resin film 1 without the protective film 2. The next E step is a step of forming another protective film 2'on the functional layer formed in the D step, which is a step to be set as necessary. In the final F step, the formed protective film 2 and The protective film 2'is peeled off to obtain a laminate of the transparent resin film 1 and the functional layer 3, which can be used for various purposes. Figure 1 is a very simplified description, so it does not describe, for example, the adhesive layer or the adhesive layer between the layers. Moreover, the protective film or the functional layer is sometimes formed on both sides of the transparent resin film 1. But this situation is not recorded.

The laminated system of the transparent resin film 1 and the protective film 2 of the present invention is formed in step C of FIG. 1 above. In the present invention, the protective film 2 is prevented from peeling or peeling off during the step of forming the functional layer 3 in the next step D The laminated body of the transparent resin film 1 and the protective film 2 warped. Hereinafter, the layers to be constructed will be described.

(Transparent resin film) The transparent resin film constituting the laminate of the present invention is composed of at least one resin selected from the group consisting of polyimide, polyamide, and polyimide imide, and is composed of A resin composition of at least one resin from the group consisting of amine, polyamide, and polyamide imide is formed. In this specification, polyimine means a polymer containing a repeating structural unit containing an amide group, and polyimide means a repeating structural unit containing an amide group and a repeating structure containing an amide group A polymer of both units, polyamide means a polymer containing repeating structural units containing an amide group. The polyimide-based polymer refers to a polymer containing at least one resin selected from polyimine and polyimide.

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

If the main structural unit of the polyimide-based polymer is a repeating structural unit represented by formula (10), it is preferable from the viewpoint of the strength and transparency of the transparent resin film. In the polyimide polymer of this embodiment, the content ratio of the repeating structural unit represented by formula (10) is preferably 40 mol% or more with respect to all repeating structural units of the polyimide-based polymer. More preferably, it is 50 mol% or more, still more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly preferably 98 mol% or more, and may also be 100 mol%.

[化1]

G and G ¹ each independently represent a tetravalent organic group, and preferably represent a tetravalent organic group having 4 to 40 carbon atoms. The above-mentioned organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. 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 tetravalent chain hydrocarbon group having 6 or less carbon atoms. In the formula, * means bonding bond, Z means 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 ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbons which may be substituted by a fluorine atom, and a specific example may be a phenylene group. In terms of easily suppressing the yellowness of the obtained transparent resin film, as G and G ¹ , preferably, formula (20), formula (21), formula (22), formula (23), and formula ( 24), the base represented by formula (25), formula (26) or formula (27).

[化2]

G ² represents a trivalent organic group, and preferably represents a trivalent organic group having 4 to 40 carbon atoms. The above-mentioned organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. As G ² , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), and formula (28) can be exemplified Or any one of the bonding bonds of the group represented by the formula (29) is substituted with a hydrogen atom and a trivalent chain hydrocarbon group with 6 or less carbon atoms. The example of Z in the formula is the same as the example of Z described for G.

G ³ represents a divalent organic group, and preferably represents a divalent organic group having 4 to 40 carbon atoms. The above-mentioned organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. As G ³ , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), and formula (28) can be exemplified Or two non-adjacent bonding bonds of the group represented by formula (29) are substituted with a hydrogen atom group and a divalent chain hydrocarbon group with 6 or less carbon atoms. The example of Z in the formula is the same as the example of Z described for G.

A, A ¹ , A ² and A ³ all represent a divalent organic group, and preferably represent a divalent organic group with 4 to 40 carbon atoms. The above-mentioned organic group may be substituted by a hydrocarbon group or a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms. In this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1-8 carbon atoms. As A, A ¹ , A ^2, and A ³ , there can be exemplified respectively: formula (30), formula (31), formula (32), formula (33), formula (34), formula (35), and formula (36) , The group represented by formula (37) or formula (38); these groups are substituted by more than one of methyl, fluoro, chloro or trifluoromethyl; and chain formulas with 6 or less carbon atoms Hydrocarbyl.

The * in the formula represents a bonding bond, Z ¹ , Z ² and Z ³ each independently represent 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 )-. Here, R ² represents a hydrocarbon group of 1 to 12 carbons which may be substituted with a halogen atom. Z ¹ and Z ² , and Z ² and Z ³ are preferably in the meta position or the para position with respect to each ring.

[化3]

In the present invention, the resin composition forming the transparent resin film may also include polyamide. The polyamide of this embodiment is a polymer mainly composed of repeating structural units represented by formula (13). Specific examples and preferred examples of the same in the polyamide A ³ G ^3, and the specific examples and preferred examples of the polyimide-based polymer in the G ^3, and A ^3. The polyamide may include two or more repeating structural units represented by formula (13) different in ^{G 3} and/or A ^3.

Polyimide-based polymers can be obtained, for example, by polycondensation of diamines and tetracarboxylic acid compounds (tetracarboxylic dianhydride, etc.). For example, they can be obtained in accordance with Japanese Patent Laid-Open No. 2006-199945 or Japanese Patent Laid-Open 2008- The synthesis was carried out by the method described in Bulletin No. 163107. As a commercially available product of polyimide, Neopulim (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd., KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd., and the like can be cited.

Examples of tetracarboxylic acid compounds used in the synthesis of polyimide polymers include aromatic tetracarboxylic acids and their anhydrides, preferably aromatic tetracarboxylic acid compounds such as dianhydrides; and aliphatic tetracarboxylic acids The acid and its anhydride are preferably aliphatic tetracarboxylic acid compounds such as dianhydride. In addition to anhydrides, the tetracarboxylic acid compound may be a tetracarboxylic acid compound derivative such as a tetracarboxylic acid chloride compound, and these may be used alone or in combination of two or more kinds.

Specific examples of aromatic tetracarboxylic dianhydrides include non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic tetracarboxylic dianhydrides. Acid dianhydride. Examples of non-condensed polycyclic aromatic tetracarboxylic dianhydrides include: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid Dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3' -Biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic 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 Yl)diphthalic dianhydride (sometimes recorded as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyl) Phenyl)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'-(terephthalic acid) dianhydride, 4, 4'-(isophthalenedioxy)diphthalic dianhydride. In addition, as the monocyclic aromatic tetracarboxylic dianhydride, 1,2,4,5-benzenetetracarboxylic dianhydride can be exemplified, and as the condensed polycyclic aromatic tetracarboxylic dianhydride, there can be exemplified 2,3,6,7-Naphthalenetetracarboxylic dianhydride.

Among them, preferred examples include: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3 '-Benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3, 3',4,4'-Diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxybenzene) Base) propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic 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'-(terephthalic acid) dianhydride and 4,4'-(isophthalic acid) Anhydrides, more preferably, 4,4'-oxydiphthalic 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 '-(Phenylenedioxy)diphthalic dianhydride. These can be used individually or in combination of 2 or more types.

As the aliphatic tetracarboxylic dianhydride, a cyclic or acyclic aliphatic tetracarboxylic dianhydride may be mentioned. The so-called cyclic aliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include: 1,2,4,5-cyclohexanetetracarboxylic dianhydride, Cycloalkane tetracarboxylic 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 their positional isomers. These can be used individually or in combination of 2 or more types. As a specific example of acyclic aliphatic tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentane tetracarboxylic dianhydride, etc. may be mentioned These can be used alone or in combination of two or more kinds. Moreover, cycloaliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride can also be used in combination.

From the viewpoint of easily improving the tensile elastic modulus, bending resistance, and optical properties of the transparent resin film, among the tetracarboxylic acid compounds, preferably, the above-mentioned alicyclic tetracarboxylic dianhydride or non-condensed polycyclic Formula of aromatic tetracarboxylic dianhydride. As more preferable specific examples, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-Dicarboxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA). These can be used individually or in combination of 2 or more types.

The polyimide-based polymer of this embodiment can also be used in addition to the anhydride of the tetracarboxylic acid used in the synthesis of the polyimide within the range of not impairing the various physical properties of the obtained transparent resin film. It is obtained by reaction of acid, tricarboxylic acid compound, dicarboxylic acid compound, their anhydrides and their derivatives.

The tricarboxylic acid compound may, for example, be aromatic tricarboxylic acid, aliphatic tricarboxylic acid, and similar chlorinated compounds, acid anhydrides, etc., and these may be used in combination of two or more kinds. Specific examples include: 1,2,4-benzenetricarboxylic acid anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and benzoic acid have a single bond,- CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene-linked compounds.

The dicarboxylic acid compound may, for example, be aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and similar chlorinated compounds, acid anhydrides, etc., and these may be used in combination of two or more kinds. Specific examples include terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; carbon number of 8 or less The chain hydrocarbon dicarboxylic acid compound and two benzoic acid skeletons are composed of -CH ₂ -, -S-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -O-, -N( R ⁹ )-, -C(=O)-, -SO ₂ -or phenylene-linked compound. These can be used individually or in combination of 2 or more types. Here, R ⁹ represents a hydrocarbon group having 1 to 12 carbons which may be substituted with a halogen atom.

As the dicarboxylic acid compound, preferred are: terephthalic acid; isophthalic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; and two benzoic acid skeletons are composed of- CH ₂ -, -C(=O)-, -O-, -N(R ⁹ )-, -SO ₂ -or phenylene-linked compound; more preferably: terephthalic acid; 4,4'- Biphthalic acid; and a compound in which two benzoic acid skeletons are linked by -O-, -NR ⁹ -, -C(=O)- or -SO _{2 -.} These can be used individually or in combination of 2 or more types.

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

As the diamine used in the synthesis of the polyimide-based polymer, an aliphatic diamine, an aromatic diamine, or a mixture of these can be mentioned. Furthermore, the term "aromatic diamine" in this embodiment refers to a diamine in which an amine group is directly bonded to an aromatic ring, and an aliphatic group or other substituents may be included in a part of its structure. The aromatic ring may be a monocyclic ring or a condensed ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a sulphur ring, but are not limited to these. Among them, preferably, a benzene ring can be exemplified. In addition, the term "aliphatic diamine" refers to a diamine in which an amine group is directly bonded to an aliphatic group, and an aromatic ring or other substituents may be included in a part of the structure.

Specific examples of aliphatic diamines include: acyclic aliphatic diamines such as hexamethylene diamine; and 1,3-bis(aminomethyl)cyclohexane, 1,4-bis( Cycloaliphatic diamines such as aminomethyl)cyclohexane, nordanediamine, 4,4'-diaminodicyclohexylmethane, etc.; these can be used alone or in combination of two or more kinds.

Specific examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diamino group Aromatic diamines with one aromatic ring such as naphthalene, 2,6-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4, 4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ingot, 3,3'-diaminodiphenyl ingot, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4- Aminophenoxy) benzene, bis[4-(4-aminophenoxy)phenyl] ash, bis[4-(3-aminophenoxy) phenyl] ash, 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'-diaminobiphenyl (sometimes referred to as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9 ,9-bis(4-aminophenyl)sulfuric acid, 9,9-bis(4-amino-3-methylphenyl)sulfuric acid, 9,9-bis(4-amino-3-chlorophenyl) ) Aromatic diamines with two or more aromatic rings, such as pyridium, 9,9-bis(4-amino-3-fluorophenyl)pyridium, etc. These can be used individually or in combination of 2 or more types.

As the aromatic diamine, preferably, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether , 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 1,4-bis(4-amino) Phenoxy) benzene, bis[4-(4-aminophenoxy)phenyl] ash, bis[4-(3-aminophenoxy)phenyl] ash, 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'-diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, more preferably, 4, 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-Bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfonate, 2,2-bis[4-(4-aminophenoxy) )Phenyl)propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis (4-Aminophenoxy)biphenyl. These can be used individually or in combination of 2 or more types.

The above-mentioned diamine may have a fluorine-based substituent. The fluorine-based substituent may, for example, be a perfluoroalkyl group having 1 to 5 carbon atoms such as trifluoromethyl group, and a fluoro group.

From the viewpoints of high transparency and low colorability, among the above-mentioned diamines, it is preferable to use one or more selected from the group consisting of aromatic diamines having a biphenyl structure. As a specific example, it is preferable to use Use selected from 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) and 4,4'-bis(4- One or more of the group consisting of aminophenoxy)biphenyl. More preferred is a diamine having a biphenyl structure and a fluorine-based substituent. As a specific example, it is more preferred to use 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) .

Polyimide-based polymers are formed by polycondensation of diamines and tetracarboxylic acid compounds (including tetracarboxylic acid compound derivatives such as chlorine compounds and tetracarboxylic dianhydrides) and include the repetition represented by formula (10) Condensed polymer of structural unit. As starting materials, in addition to these, tricarboxylic acid compounds (including tricarboxylic acid compound derivatives such as chlorinated compounds and tricarboxylic anhydrides) and dicarboxylic acid compounds (including chlorinated compounds such as derivatives) are sometimes used. . In addition, the polyamide is a condensation type polymer formed by the condensation polymerization of a diamine and a dicarboxylic acid compound (including derivatives such as a chloride compound) and includes a repeating structural unit represented by formula (13).

The repeating structural units represented by formula (10) and formula (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 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 the tetracarboxylic acid compound can be appropriately adjusted within a range of preferably 0.9 mol or more and 1.1 mol or less of the tetracarboxylic acid relative to 1.00 mol of the diamine. In order to exhibit high folding resistance, the obtained polyimide-based polymer preferably has a high molecular weight. In this regard, the tetracarboxylic acid is more preferably 0.98 mol or more and 1.02 mol or less relative to 1.00 mol of diamine. It is preferably 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 the amine based on the obtained polymer terminal is low, and it is more preferable that the tetracarboxylic acid compound is 1.00 mol relative to the diamine. The equivalent carboxylic acid compound is 1.00 mol or more.

The number of fluorine in the molecule of diamine and carboxylic acid compound (such as tetracarboxylic acid compound) can be adjusted, and the amount of fluorine in the obtained polyimide polymer can be adjusted based on the quality of the polyimide polymer It becomes 1 mass% or more, 5 mass% or more, 10 mass% or more, 20 mass% or more. Since the higher the fluorine ratio, the higher the raw material cost, the upper limit of the fluorine content is preferably 40% by mass or less. The fluorine-based substituent may be present in either of the diamine or the carboxylic acid compound, or may be present in both. There are cases where the YI (yellowness index) value is particularly lowered by including a fluorine-based substituent.

The polyimide-based polymer of this embodiment may also be a copolymer containing a plurality of the above-mentioned repeating structural units of different types. Regarding the weight average molecular weight in terms of standard polystyrene conversion of the polyimide-based polymer, in terms of improving the flexibility during film formation, it is usually 100,000 or more, preferably 200,000 or more, more preferably 250,000 or more, and further It is preferably 300,000 or more, and in terms of obtaining a varnish with a moderate concentration and viscosity to improve the film formability, it is usually 800,000 or less, preferably 750,000 or less, more preferably 600,000 or less, and still more preferably 500,000 the following.

Polyimide-based polymers and polyamides, by containing fluorine-containing substituents, show the following tendency: the tensile elastic modulus during film formation increases and the YI value decreases. If the tensile modulus of the film is high, it tends to suppress the occurrence of damage and wrinkles. From the viewpoint of the transparency of the film, the polyimide-based polymer and polyamide preferably have a fluorine-containing substituent. As specific examples of the fluorine-containing substituent, a fluoro group and a trifluoromethyl group may be mentioned.

The content of fluorine atoms in the polyimide polymer and the mixture of the polyimide polymer and the polyimide is based on the mass of the polyimide polymer or the mass of the polyimide polymer and the polyimide The total mass of amines is a reference, and each is preferably 1% by mass or more and 40% by mass or less, and more preferably 5% by mass or more and 40% by mass or less. If the content of fluorine atoms is 1% by mass or more, the YI value at the time of film formation can be further reduced, and the transparency tends to be more improved. If the content of fluorine atoms is within 40% by mass, the high molecular weight of polyimide tends to be easier.

In the present invention, the content of the polyimide polymer and/or polyamide in the resin composition forming the transparent resin film relative to the solid content of the resin composition is preferably 40% by mass or more, more preferably It is 50% by mass or more, more preferably 70% by mass or more, and may be 100% by mass. If the content of the polyimide-based polymer and/or polyamide is more than the above lower limit, the flexibility of the transparent resin film is good. In addition, the so-called solid content refers to the total amount of the components after removing the solvent from the resin composition.

In the present invention, the resin composition forming the transparent resin film may further contain inorganic materials such as inorganic particles in addition to the above-mentioned polyimide-based polymer and/or polyamide. The inorganic material may, for example, be silicon oxide particles, titanium particles, aluminum hydroxide, zirconium oxide particles, barium titanate particles, and other inorganic particles. In addition, silicon oxides such as quaternary alkoxysilanes such as tetraethyl orthosilicate may be mentioned. From the viewpoint of the stability of the varnish and the dispersibility of inorganic materials, the compound preferably includes silica particles, aluminum hydroxide, and zirconia particles, and more preferably silica particles.

The average primary particle size of the inorganic material is preferably 5-100 nm, more preferably 8-50 nm, and still more preferably 8-30 nm. If the above-mentioned average primary particle size is 100 nm or less, the transparency tends to improve. If the above-mentioned average primary particle size is 5 nm or more, the cohesive force of the inorganic material tends to be weak and easy to handle.

In the present invention, the silica particles may be silica sol obtained by dispersing silica particles in an organic solvent, etc., or silica fine particles produced by a gas phase method can also be used, but in terms of easy handling, Preferably, it is a silica sol produced by a liquid phase method.

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

In the present invention, when an inorganic material is contained in the resin composition, its content relative to the solid content of the resin composition is preferably 0.01% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 60% by mass or less , And more preferably 20% by mass or more and 50% by mass or less. If the content of the inorganic material in the resin composition is within the above range, it tends to be easy to have both the transparency and mechanical strength of the transparent resin film. In addition, the so-called solid content refers to the total amount of the components after removing the solvent from the resin composition.

In addition to the components described above, the resin composition forming the transparent resin film may further contain other components. Examples of other components include antioxidants, mold release agents, light stabilizers, bluing agents, flame retardants, lubricants, and leveling agents.

In the present invention, when the resin composition contains other components other than resin components such as polyimide polymers and inorganic materials, the content of the other components relative to the total mass of the transparent resin film is preferably 0.01% or more. Mass% or less, more preferably 0.01% or more and 10 mass% or less.

In the present invention, the transparent resin film can be produced from, for example, a varnish containing a polyimide-based polymer obtained by selecting and reacting the above-mentioned tetracarboxylic acid compound, the above-mentioned diamine, and the above-mentioned other raw materials. And/or the reaction liquid of polyamide, the inorganic material used as needed, and the resin composition of other components are prepared by adding a solvent, mixing and stirring. In the above resin composition or varnish, it is also possible to use purchased solutions of polyimide polymers, etc., or purchased solutions of solid polyimide polymers, etc., instead of polyimide polymers, etc. The reaction solution.

As a solvent that can be used to prepare a varnish, one that can dissolve or disperse resin components such as polyimide-based polymers can be appropriately selected. As the solvent, one type may be used alone or two or more types may be used in combination. Furthermore, when two or more solvents are used, it is preferable to select the type of solvent so that the boiling point of the solvent with the highest boiling point falls within the following range among the solvents used. From the viewpoints of the solubility, coating and drying properties of the resin component, the boiling point of the solvent is preferably 120 to 300°C, more preferably 120 to 270°C, still more preferably 120 to 250°C, and particularly preferably 120 ～230℃. Specific examples of such a solvent include amine-based solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; γ -Lactone-based solvents such as butyrolactone and γ-valerolactone; ketone-based solvents such as cyclohexanone, cyclopentanone, and methyl ethyl ketone; acetate-based solvents such as butyl acetate and amyl acetate; dimethyl Sulfur-containing solvents such as base sulfide, dimethyl sulfide, and cyclobutyl sulfide, carbonate-based solvents such as ethylene carbonate and propylene carbonate, etc. Among them, it is preferably selected from N,N-dimethylacetamide (boiling point: 165°C) and γ-butyrolactone in terms of excellent solubility in polyimide-based polymers and polyamides. Ester (boiling point: 204°C), N-methylpyrrolidone (boiling point: 202°C), cyclopentanone (boiling point: 131°C), butyl acetate (boiling point: 126°C) and amyl acetate (boiling point: 149°C) ) The solvent in the group consisting of.

The amount of the solvent is not particularly limited, as long as it is selected in a way that the viscosity of the varnish can be operated, and it is preferably 50-95% by mass, more preferably 75-95% by mass relative to the total amount of the varnish. , More preferably 80 to 95% by mass.

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. If the thickness of the transparent resin film is within the above range, the flexibility of the transparent resin film tends to become good.

The transparent resin film of the present invention is excellent in transparency, and the haze at a thickness of 50 μm is preferably 1.0% or less, more preferably 0.7% or less, and still more preferably 0.5% or less. In addition, when the thickness of the transparent resin film is 50 μm, the total light transmittance is preferably 85.0% or more, more preferably 87.0% or more, still more preferably 88.0% or more, still more preferably 89.0% or more, and particularly preferably 90.0 %the above. If the haze and total light transmittance of the transparent resin film constituting the laminate are within the above ranges, a laminate suitable for optical applications requiring high transparency is obtained.

The transparent resin film of the present invention can be manufactured using well-known methods and devices/equipment. Specifically, for example, it can be manufactured by a method including the following steps: Mixing and stirring the resin composition used to form the transparent resin film with the solvent to obtain a varnish, and coating the varnish on the substrate; By drying the applied varnish to remove the solvent, a transparent resin film layer is formed on the supporting substrate; After drying the obtained transparent resin film layer, it is stretched; and The supporting substrate is peeled from the layer of the transparent resin film formed on the supporting substrate.

When the laminate of the present invention is produced by the above-mentioned method, the supporting substrate for coating the varnish is a film-like substrate, for example, a resin film substrate or a steel substrate (e.g., SUS tape). As the resin film substrate, for example, there is a polyethylene terephthalate (PET) film. The thickness of the substrate is not particularly limited, and is, for example, 10 to 500 μm, 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 varnish becomes a desired range. The drying to remove the solvent can be performed by natural drying, air drying, heat drying or reduced pressure drying and a combination of these. From the viewpoint of production efficiency and the like, heating and drying are preferred. The drying conditions may be appropriately determined according to the type of solvent used or the solvent content in the film, etc., within a range that does not impair the optical properties of the transparent resin film. For example, it can be heated at a temperature of 50 to 300°C, preferably 70 to 250°C, for example, for about 5 to 100 minutes.

The amount of residual solvent contained in the film after heating and drying is preferably 1-20% by mass, more preferably 3-18% by mass, and still more preferably 5-15% by mass relative to the mass of the film peeled from the substrate . In addition, the amount of residual solvent contained in the transparent resin film obtained by further drying the film peeled from the substrate is preferably 0.001 to 2.0% by mass, more preferably 0.005 to 1.5% by mass, and still more preferably 0.01 -1.0% by mass, more preferably 0.01-0.8% by mass.

(Protective film) The laminate of the present invention includes a protective film bonded to the above-mentioned transparent resin film. There are cases where a release film (separator) is included in the original protective film, but the protective film in the present invention refers to a separate base material or a base material and an adhesive layer from which the release film has been peeled. The protective film can be attached to only one side of the transparent resin film, or attached to both sides. The protective film attached 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 can be a peelable film that can protect the surface of the transparent resin film. Examples of protective films include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and polyolefin resin films such as polyethylene and polypropylene films. Film, acrylic resin film, etc. The protective film can be used in the form of a single layer of these materials, or a film containing multiple layers. The protective film is preferably a resin selected from the group consisting of polyolefin resin films, polyethylene terephthalate resin films, and acrylic resin films, and more preferably polyester resin films and acrylic resins The film is more preferably a polyester resin film. When a protective film is attached to both sides of the laminate, the protective film on each side may be the same or different.

The polyester resin film is preferably a biaxially stretched polyester film, and more preferably a biaxially stretched polyethylene terephthalate film.

Regarding the heat shrinkage rate of the biaxially stretched polyethylene terephthalate film in the width direction (TD direction) and the length direction (MD direction) after heat treatment at 150°C for 30 minutes, both are preferably 2.00% Below, 1.00% or less is more preferable, and 0.50% or less is still more preferable.

The polyester resin film may be provided with functions such as slipperiness, easy adhesion, and antistatic properties by in-line coating after surface treatment such as corona treatment, flame treatment, plasma treatment, etc., if necessary.

The antistatic agent is preferably an ionic compound with a melting point of 30 to 80°C or a quaternary ammonium salt type ionic compound containing an acrylic group.

Furthermore, as other components, copolymerizable (meth)acrylic monomers containing alkylene oxide, (meth)acrylamide monomers, dialkyl substituted acrylamide monomers, and interface Active agents, hardening accelerators, plasticizers, fillers, hardening retarders, processing aids, anti-aging agents, antioxidants, antistatic agents and other well-known additives. These can be used individually or in combination of 2 or more types.

As the base film of the adhesive layer and the release film (separator) for protecting the adhesive surface, resin films such as polyester films can be used. For the base film, antifouling treatment can be performed on the side opposite to the side where the adhesive layer of the resin film is formed using silicone-based, fluorine-based release agents or coating agents, silica particles, etc., and antistatic agents The coating or kneading, etc. implement antistatic treatment. For the release film, the surface of the adhesive layer that is joined to the adhesive surface can be subjected to a release treatment with a silicone-based or fluorine-based release agent.

The thickness of the protective film is not particularly limited. From the viewpoint of protecting the transparent resin film, it is usually 10 μm or more, preferably 20 μm or more, and more preferably 25 μm or more. On the other hand, from the viewpoint of film handling , Preferably 300 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less, and still more preferably 100 μm or less. When a protective film is attached to both sides of the transparent resin film, the thickness of the protective film on each side can be the same or different.

The thickness of the base film is preferably 15 μm or more, more preferably 18 μm or more, still more preferably 25 μm or more, still more preferably 30 μm or more, particularly preferably 35 μm or more, and preferably 150 μm or less, It is more preferably 125 μm or less, still more preferably 100 μm or less, and still more preferably 85 μm or less.

The thickness of the adhesive layer is usually 0.1 μm or more, preferably 1 μm or more, more preferably 3 μm or more, and more preferably 5 μm or more.

When in-line coating is used to impart functions such as easy slippage, easy bonding, and antistatic properties, the thickness of the layer with these functions is preferably 0.05 μm or more and 5 μm or less, more preferably 0.075 μm or more. 3 Below μm. Regarding these functions, it may be provided by stacking a single layer having these functions, or a single layer may be provided with multiple functions.

The protective film may be attached to the transparent resin film using an adhesive as needed. The adhesive is not particularly limited, as long as it has adhesiveness and releasability. For example, it preferably contains acrylic resin, rubber resin, ethylene-vinyl acetate copolymer resin, polyester resin, and acetate resin. , Polyether-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyolefin-based resins, silicone resins, etc. are used as adhesives. From the viewpoint of practicality, the adhesive layer more preferably contains an acrylic resin or an ethylene-vinyl acetate copolymer resin as an adhesive, and more preferably contains an acrylic resin. The adhesive may also contain other ingredients as needed. As other components, an antistatic agent, a coloring agent, an ultraviolet absorber, etc. are mentioned, for example.

The copolymer of the main agent used in the adhesive composition can be obtained by making (A) a (meth)acrylate monomer with an alkyl group of 4 to 10 carbon atoms, and (B) a copolymerizable monomer containing a hydroxyl group. It is synthesized by polymerization of (C) a copolymerizable monomer containing a carboxyl group, and (D) a polyalkylene glycol mono(meth)acrylate monomer. The polymerization method of the copolymer is not particularly limited, and appropriate polymerization methods such as solution polymerization and emulsion polymerization can be used. When (H2) an acryloyl group-containing quaternary ammonium salt type ionic compound is used as the (H) antistatic agent, the (A) alkyl group can have a carbon number of 4-10 (methyl) Acrylate monomers, (B) monomers containing hydroxyl groups and copolymerizable, (C) monomers containing carboxyl groups and copolymerizable, (D) polyalkylene glycol mono(meth)acrylate monomers, And (H2) a quaternary ammonium salt type ionic compound containing acrylic group is synthesized by polymerization. Regarding the adhesive composition, (E) a trifunctional or higher isocyanate compound, (F) a crosslinking retarder, (G) a crosslinking catalyst, (H) an antistatic agent, and (I) may be formulated into the above-mentioned copolymer. Polyether modified silicone compound, and any suitable additives. Furthermore, when the (H2) propylene group-containing quaternary ammonium salt type ionic compound is polymerized in the copolymer of the main agent, (H) antistatic agent may be further added to the copolymer.

The above-mentioned copolymer is preferably an acrylic polymer using (meth)acrylic acid ester monomers or acrylic monomer components such as (meth)acrylic acid and (meth)acrylamides as raw materials. The amount of the acrylic monomer component used is preferably 50 to 100% by mass relative to the copolymer. In addition, the acid value of the acrylic polymer is preferably 0.01 to 8.0. If the acid value is within the above range, the performance of preventing paste residue can be improved. Here, the so-called "acid value" is one of the indexes indicating the content of acid, expressed by the mg of potassium hydroxide required to neutralize 1 g of the carboxyl group-containing polymer.

The gel fraction of the adhesive layer formed by cross-linking the adhesive composition is preferably 95-100%. If the gel fraction is within the above range, the adhesive force will not become too large at a lower peeling speed, and the elution of unpolymerized monomers or oligomers from the copolymer will decrease, which can improve secondary processability or high temperature , Durability under high humidity, thereby inhibiting the pollution of the adherend. Regarding the gel fraction, the adhesive layer was aged for 7 days under an environment of 23°C and 53%RH, and then the quality of the adhesive layer was accurately measured, and then the adhesive layer was immersed in toluene at room temperature After 24 hours, filter with 200 mesh wire mesh. Thereafter, after drying the filter at 100°C for 1 hour, the mass of the remaining insoluble part was measured, and the gel fraction of the crosslinked adhesive layer was calculated according to the following formula. Gel fraction (%) = mass of insoluble part (g)/mass of adhesive layer (g)×100

Regarding the peeling strength of the adhesive layer and acrylic resin formed by cross-linking the above adhesive composition, the adhesive force at a low-speed peeling area of 0.3 m/min is preferably 0.01 N/25 mm or more, and the high-speed peeling area is 30 m Adhesive force at 30 m/min is better than 3.00 N/25 mm, and at low speed peeling area 0.3 m/min, the adhesive force is better than 0.02 N/25 mm, and at high speed peeling area at 30 m/min. The adhesion force is more preferably 2.50 N/25 mm or less, and the adhesion force in the low-speed peeling area at 0.3 m/min is more than 0.03 N/25 mm, and the adhesion force at the high-speed peeling area at 30 m/min is even better. 2.20 N/25 mm or less, through this, the adhesive force will not change greatly due to the different peeling speed, and the peeling can be performed quickly by high-speed peeling. In addition, when the surface protective film is temporarily peeled off for reattachment, excessive force is not required, and it is easy to peel off from the adherend.

(Layered body) In the present invention, in a laminate including the above-mentioned transparent resin film and protective film as layers, the tensile elastic modulus E1 and thickness T1 of the laminate satisfy the formula (1), 350＜E1×T1＜1,000 (1) And the tensile elastic modulus E1 of the laminate and the tensile elastic modulus E2 of the protective film satisfy the formula (2), 1.0≦E1/E2≦6.5 (2) The above conditions help prevent peeling and warping of the protective film.

Regarding the tensile elastic modulus, it is necessary to measure the tensile elastic modulus E1 of the laminate itself and the tensile elastic modulus E2 of the protective film. The tensile modulus of elasticity can be measured using a common device for measuring the tensile modulus of elasticity, such as "Autograph AG-IS" manufactured by Shimadzu Corporation. The details of the measurement are described in the examples. The thickness can be a thickness that is usually measured, for example, it can be measured using a Micrometer (manufactured by Mitutoyo Co., Ltd.). The unit of tensile modulus is GPa, and the unit of thickness is μm.

In the present invention, the product of the tensile elastic modulus E1 of the laminate and the thickness T1 of the laminate is usually 300-1,000, preferably 330-900, more preferably 350-800, and still more preferably 380-750. In addition, the ratio (E1/E2) of the tensile elastic modulus E1 of the laminate to the tensile elastic modulus E2 of the protective film is usually 1.0 or more and 6.5 or less, preferably 1.1 or more and 5.0 or less, more preferably 1.2 or more and 4.0 Hereinafter, it is more preferably 1.5 or more and 3.0 or less, and still more preferably 1.5 or more and 3.3 or less. As mentioned above, it is preferable that the laminate has a higher tensile modulus E1 and a thicker thickness T1, but there are limits to each, so the product of the tensile modulus E1 and the thickness T1 needs to fall within a specific range . Furthermore, the tensile elastic modulus E1 of the laminate and the tensile elastic modulus E2 of the protective film are preferably the same, and therefore, the range of 1.0≦E1/E2≦6.5 is preferable.

In the present invention, the relationship between the tensile modulus of elasticity, the thickness of the laminate, and the tensile modulus of the protective film is specified in the above-mentioned manner, and the preferable range of each value can also be specified. Specifically, the tensile modulus E1 of the laminate is preferably 2.0 GPa or more, more preferably 2.5 GPa or more, still more preferably 3.0 GPa or more, still more preferably 3.7 GPa or more, and preferably 10.0 GPa or less , More preferably 8.0 GPa or less, still more preferably 7.0 GPa or less, and still more preferably 5.7 GPa. The thickness T1 of the laminate is usually 40 to 300 μm, preferably 50 to 300 μm, more preferably 80 to 200 μm. The tensile modulus E2 of the protective film is preferably 0.7 GPa or more, more preferably 1.0 GPa or more, still more preferably 1.5 GPa or more, still more preferably 1.8 GPa or more, and preferably 10.0 GPa or less, and more preferably It is 7.0 GPa or less, more preferably 5.0 GPa or less, and still more preferably 2.7 GPa or less. The thickness T2 of the protective film is usually 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. When it is in the above range, the effect of preventing peeling and warping of the laminate of the transparent resin film and the protective film is improved.

(Functional layer) As described in the above description of FIG. 1, in a transparent resin film, a functional layer can be formed on the side opposite to the side where the protective film exists. Specifically, the functional layer can be hard coating function, antistatic function, anti-glare function, low reflection function, antireflection function, antifouling function, gas barrier function, primer function, electromagnetic wave shielding function, undercoating function, ultraviolet absorption function , Adhesive function, hue adjustment function and other common functions used in optical films. The functional layer may be a layer having one function, or a layer having two or more functions. From the viewpoint of being easy to use as a front panel of a flexible display device, at least one of the functional layers is preferably selected from the group consisting of hard coating function, antistatic function, anti-glare function, low reflection function, anti-reflection function and anti-fouling function. The layer of at least one function in the group of functions. The functional layer may have a plurality of functions in one layer, or two or more layers with each function may be laminated. When two or more layers are stacked, the stacking order can be appropriately set according to its function. These layers are laminated on one or both sides of the transparent resin film. In the case of laminated layers on both sides, the thickness, function, and order of the layers laminated on each side may be the same or different. In addition, a protective film may be further formed on the functional layer.

The thickness of the functional layer can be appropriately set according to the target function. From the viewpoint of easily improving the weight reduction and optical homogeneity of the laminate, it is preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less, And it is preferably 3 μm or more.

＜Hard coating function＞ The surface hardness of the hard coat layer is preferably F or more, more preferably H or more, and still more preferably 2H or more. If the surface hardness of the hard coat layer is more than the above lower limit, when the laminate is used as a front panel (window film) of an image display device, damage to the surface of the image display device can be advantageously suppressed. It can help prevent the shrinkage and expansion of polyimide-based films. The surface hardness of the hard coat layer is usually below 9H. Furthermore, in the present invention, the surface hardness can be measured in accordance with JIS K 5600-5-4:1999.

The hard coat layer contains a hard coat resin. Examples of the hard coat resin include acrylic resins, epoxy resins, urethane resins, benzyl chloride resins, vinyl resins, or silicones. UV-curable, electron-beam-curable, or thermo-curable resins such as resins or mixed resins. In particular, from the viewpoint of mechanical properties such as surface hardness and industrial viewpoints, the hard coat layer is preferably made of acrylic resin.

The acrylic resin may, for example, be urethane acrylate, urethane methacrylate (hereinafter, acrylate and/or methacrylate will be referred to as (meth)acrylate), (meth)acrylic acid Alkyl esters, (meth)acrylates of ester compounds, epoxy (meth)acrylates, and polymers and copolymers thereof. Specific examples include methyl (meth)acrylate, butyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenyl (meth)acrylate, Ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, ethylene glycol di(meth) Acrylate, propylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and polymers and copolymers thereof.

The hard coat layer may include a photopolymerization initiator and/or an organic solvent, and may also include inorganic oxides such as silica particles, alumina, and polyorganosiloxane. In a preferred embodiment of the present invention, in terms of mechanical properties such as surface hardness and industrial viewpoints, the hard coat layer is made of acrylic resin and silicon oxide particles.

The thickness of the hard coat layer can be appropriately adjusted according to the application of the image display device to which the laminate is applied, and it can be, for example, 1-50 μm, especially 2-30 μm. Furthermore, in the present invention, the thickness of the hard coat layer can be calculated based on the difference between the thickness of the substrate and the thickness of the substrate using, for example, a contact type digital gauge.

In a preferred embodiment of the present invention, the hard coat layer may also be a stretched film. The hard coat layer as a stretched film can be prepared by drying the coating film of the following hard coat composition, then performing stretching treatment and irradiating high energy rays.

＜Antistatic function＞ The antistatic function is the function of preventing static electricity on the surface of the optical film. In the laminate of the present invention, the functional layer may be a layer having an antistatic function (antistatic layer). As a method of forming an antistatic layer, in addition to a method of adding an antistatic agent to the composition for forming a hard coat layer to impart an antistatic function to the hard coat layer, the following method may also be exemplified: The composition for forming an antistatic layer obtained by an electrostatic agent is coated on the optical film or the functional layer laminated on the optical film, and dried as necessary to form a separate film. The antistatic agent can be included in a part of the resin constituting the functional layer (such as the cured product of the active energy ray curable compound) as a structural unit with antistatic function, and can also be added as an additive to the resin forming the functional layer. When an antistatic agent is added as an additive, the addition amount is preferably 0.01-20% by mass, more preferably 0.05-10% by mass, and still more preferably 0.1 relative to the solid content of the composition for forming a functional layer. ～10% by mass.

＜Anti-glare function＞ The anti-glare function is a function that prevents external light from being reflected by scattering and reflecting light. In the laminate of the present invention, the functional layer may be a layer having an anti-glare function (anti-glare layer). As the anti-glare layer, well-known articles can be suitably used. For example, a resin composition containing at least one type of light-transmitting fine particles in a light-transmitting resin can be used to form a layer with fine concavo-convex shapes on the surface, thereby imparting an anti-glare function. More specifically, such an anti-glare layer can be formed by, for example, coating a translucent resin solution obtained by dispersing translucent fine particles as a filler on an optical film, and using the translucent fine particles as the anti-glare layer The convex part in the surface is formed by adjusting the thickness of the coating. In addition, in this specification, the term "transparent" means that light can be substantially transmitted regardless of the presence or absence of scattered light inside the substance.

Translucent particles Examples of light-transmitting fine particles include (meth)acrylic resins, melamine resins, polyethylene resins, polystyrene resins, polycarbonate resins, vinyl chloride resins, silicone resins, and acrylic-styrene copolymers. Organic particles such as calcium carbonate, silica, alumina, barium carbonate, barium sulfate, titanium oxide, glass and other inorganic particles. One kind or two or more kinds of fine particles can be used as the light-transmitting fine particles. In order to obtain the desired anti-glare properties, the type, particle size, refractive index, content, etc. of the translucent fine particles can be appropriately adjusted.

The particle diameter of the light-transmitting fine particles is preferably 0.5 to 5 μm, more preferably 1 to 4 μm. If the particle size of the light-transmitting fine particles is within the above range, it is easy to obtain the desired light diffusion effect, and it is easy to form irregularities on the surface of the anti-glare layer, so it is easy to obtain a sufficient anti-glare effect. Furthermore, the surface shape of the anti-glare layer is not rough, and there is a tendency that the haze value does not increase significantly.

The difference in refractive index between the light-transmitting fine particles and the light-transmitting resin is preferably 0.02 to 0.2, more preferably 0.04 to 0.1. If the refractive index difference is within the above-mentioned range, it is easy to obtain a sufficient light diffusion effect, and the whole layered body is unlikely to turn white.

The addition amount of the translucent fine particles is preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass relative to 100 parts by mass of the translucent resin. If the addition amount is within the above range, it is easy to obtain a sufficient light diffusion effect, and the whole layered body is unlikely to turn white.

In the case of adjusting the particle size, addition amount, and/or the refractive index difference between the light-transmitting fine particles and the light-transmitting resin to the above-mentioned range, even if the haze of the anti-glare layer is high The clearness of transmission in the area will not decrease, so it is easy to prevent glare on the surface, and in areas with low haze, it is easy to prevent glare while maintaining high clearness of transmission.

Translucent resin The translucent resin constituting the anti-glare layer is not particularly limited, as long as it has translucency. For example, in addition to the cured product of the active energy ray curable compound as described above, there can be exemplified: thermosetting Hardened resins; thermoplastic resins; metal alkoxide polymers, etc. Among them, a cured product of an active energy ray-curable compound is preferred. When using an ultraviolet curable resin or the like as an active energy ray-curable compound, as described above, a photopolymerization initiator (radical polymerization initiator) can be contained in the coating solution, and the active energy ray can be irradiated The coating layer is hardened.

Examples of thermosetting resins include thermosetting urethane resins containing acrylic polyols and isocyanate prepolymers, phenol resins, urea melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, etc. .

Examples of thermoplastic resins include cellulose derivatives such as acetyl cellulose, nitrocellulose, acetyl butyl cellulose, ethyl cellulose, and methyl cellulose; vinyl acetate and its copolymers, vinyl chloride and Its copolymers, vinylidene chloride and its copolymers and other vinyl resins; polyvinyl formal, polyvinyl butyral and other acetal resins; acrylic resins and their copolymers, methacrylic resins and their copolymers (Meth)acrylic resins; polystyrene resins; polyamide resins; polyester resins; polycarbonate resins, etc.

As the metal alkoxide-based polymer, a silicon oxide-based matrix using a silanoxide-based material as a raw material can be used. Specifically, the metal alkoxide-based polymer may be an inorganic or organic-inorganic composite matrix obtained by dehydrating and condensing a hydrolyzate of alkoxysilane such as tetramethoxysilane and tetraethoxysilane.

When a cured product of a thermosetting resin or a metal alkoxide-based polymer is used as a translucent resin, heating may be necessary after applying the coating liquid.

In addition, the refractive index of the ultraviolet curable resin is generally the same as that of glass, about 1.5, but the refractive index of the ultraviolet curable resin used may be lower compared with the refractive index of the above-mentioned light-transmitting fine particles. In this case, TiO ₂ (refractive index; 2.3 to 2.7), Y ₂ O ₃ (refractive index; 1.87), TiO 2 (refractive index; 2.3 to 2.7), Y 2 O 3 (refractive index; 1.87), La ₂ O ₃ (refractive index; 1.95), ZrO ₂ (refractive index; 2.05), Al ₂ O ₃ (refractive index; 1.63), etc. are added to the translucent resin to increase the refractive index of the translucent resin, and The refractive index of the transparent resin is adjusted to a preferable range.

The composition for forming an antiglare layer can be manufactured by dispersing light-transmitting fine particles in a composition containing a light-transmitting resin and a solvent (for example, the composition for forming a hard coat layer). The time to disperse the light-transmitting fine particles and the dispersion method are not particularly limited.

The composition for forming an anti-glare layer is used as a coating liquid, applied to the surface of the optical film or the surface of the functional layer laminated on the optical film, and dried to form an anti-glare layer. Coating can be carried out by usual methods, such as microgravure coating, roll coating, dip coating, spin coating, die nozzle coating, casting transfer, flow coating, spray coating, etc. To proceed. Thereafter, the ultraviolet curable resin can be cured by irradiating ultraviolet rays. The intensity of the irradiated ultraviolet rays, the irradiation time, etc. can be appropriately selected according to the type of the curable compound used, the thickness of the layer containing the curable compound, and the like. Ultraviolet rays can also be irradiated in an inert gas atmosphere. If it is necessary to irradiate ultraviolet rays in an inert gas atmosphere, for example, it is sufficient to perform active energy ray irradiation in a container sealed with an inert gas. As the inert gas, nitrogen, argon, etc. can be used.

As another method of forming the anti-glare layer, embossing can be used. In this method, after coating the composition for forming an anti-glare layer on an optical film or a functional layer laminated on the optical film, a mold (embossing roll) with a specific surface unevenness is pressed against the coating layer. If necessary, the coating layer is hardened to provide unevenness on the surface of the coating layer. After the anti-glare layer is peeled off from the embossing roll, in order to further promote the hardening reaction of the anti-glare layer, it is also effective to perform a second hardening step in which ultraviolet rays are irradiated again from the side of the anti-glare layer.

The haze of the anti-glare layer is preferably 0.1-50%. The haze of the anti-glare layer can be measured by a method based on JIS K 7361. The thickness of the anti-glare layer can be appropriately adjusted, for example, so that the haze of the anti-glare layer falls within the above-mentioned range, and is preferably 2 to 20 μm. If the thickness of the anti-glare layer is in the above range, it is easy to obtain a sufficient anti-glare effect, and it is easy to prevent cracking of the anti-glare layer, and it is easy to prevent the anti-glare layer from curling due to the hardening and shrinkage of the anti-glare layer, resulting in reduced productivity.

The anti-glare layer may also contain an antistatic agent. By containing an antistatic agent, an anti-glare layer with antistatic function can be obtained. The antistatic agent may, for example, be the same as the antistatic agent added to the hard coat layer described above.

The anti-glare layer may have a low-reflection layer on the outermost surface, that is, on the uneven surface side. Although it exhibits sufficient anti-glare function without a low-reflection layer, the anti-glare performance can be further improved by providing a low-reflection layer on the outermost surface. As the low reflection layer, the following can be applied.

＜Anti-reflection function and low reflection function＞ Anti-reflection function and low-reflection function are functions to prevent or reduce the reflection of external light. In the laminated body of the present invention, the functional layer may be a layer having a function of preventing reflection of external light (anti-reflection layer), or a layer having a function of reducing reflection of external light (low reflection layer). The anti-reflection layer and the low-reflection layer may be a single layer or multiple layers.

Anti-reflective layer The anti-reflection layer may have a low refractive index layer. In addition, the anti-reflection layer may be a layer having a multilayer structure including a low refractive index layer, and further including a high refractive index layer and/or a medium refractive index layer laminated between the low refractive index layer and the optical film. The above-mentioned hard coat layer may also be provided between the anti-reflection layer and the optical film.

The thickness of the anti-reflection layer is preferably 0.01 to 1 μm, more preferably 0.02 to 0.5 μm. Examples of the anti-reflection layer include: a low-refractive index layer having a lower refractive index (for example, a refractive index of 1.3 to 1.45) than the optical film or functional layer for which the anti-reflection layer is laminated; alternately laminated multiple layers containing inorganic compounds The low refractive index layer of the thin film and the high refractive index layer of the thin film containing inorganic compounds. Here, the refractive index of the high refractive index layer only needs to be greater than the refractive index of the low refractive index layer, and is preferably 1.60 or more.

The material for forming the above-mentioned low refractive index layer is not particularly limited, as long as it is a material with a lower refractive index. For example, resin materials such as active energy ray-curable resins (e.g. ultraviolet-curable acrylic resins), mixed materials obtained by dispersing inorganic particles such as colloidal silica in the resin, and metal alkoxides such as tetraethoxysilane are used. The sol-gel materials, etc. The materials for forming the low refractive index layer can be polymers after polymerization, or monomers or oligomers that become precursors. In addition, the material constituting the anti-reflective layer can impart an anti-fouling function to the anti-reflective layer, so it is preferably a fluorine-containing compound.

The high refractive index layer can be formed by the following method: coating a cured product containing the active energy ray-curable resin or a translucent resin such as a metal alkoxide polymer, as well as inorganic microparticles and/or organic microparticles After the liquid, the coating layer is hardened as necessary. Examples of the inorganic fine particles include zinc oxide, titanium oxide, cerium oxide, aluminum oxide, silane oxide, tantalum oxide, yttrium oxide, ytterbium oxide, zirconium oxide, antimony oxide, and indium tin oxide (ITO). The high refractive index layer containing the inorganic fine particles can also have an antistatic function.

As a method of manufacturing a multilayer film formed by laminating transparent thin films of inorganic compounds (metal oxides, etc.) with different refractive indices, chemical vapor deposition (CVD) method, physical vapor deposition (PVD) method, and metal alkoxide can be exemplified The sol/gel method of metal compounds such as substances forms a colloidal metal oxide particle film and post-treatment (ultraviolet radiation: Japanese Patent Laid-Open No. 9-157855; plasma treatment: Japanese Patent Laid-Open No. 2002-327310) And the method of forming a thin film, etc.

On the other hand, from the viewpoint of ease of improving productivity, it is also preferable to laminate an anti-reflection layer by coating a thin film obtained by dispersing inorganic particles in a matrix. Furthermore, by coating the composition for forming an anti-reflective layer obtained by dispersing inorganic particles in a matrix, when the anti-reflective layer is laminated, it is also possible to form fine concavities and convexities on the coated surface, thereby imparting anti-glare to the anti-reflective layer Features.

Low-reflection layer The low-reflection layer is a layer formed of a low-refractive index material whose refractive index is lower than that of the optical film used as the base material. The low refractive index layer can be formed by the following method: after coating a cured product containing the active energy ray curable resin or a translucent resin such as a metal alkoxide polymer, and a coating liquid of inorganic fine particles, if necessary Harden the coating layer. Specific examples of such a low refractive index material include lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), cryolite ( 3NaF-AlF ₃ or Na ₃ AlF ₆ ) is an inorganic low-reflective material obtained from fine particles of inorganic materials; fluorine-based or silicone-based organic compounds, thermoplastic resins, thermosetting resins, UV-curable resins, and other organic low-reflection materials.

＜Antifouling function＞ The antifouling function is the function of preventing stains, and is a function obtained by imparting water repellency, oil repellency, sweat resistance, stain resistance, fingerprint resistance, etc. to the layer. In the laminate of the present invention, the functional layer may be a layer having an antifouling function (antifouling layer). The material used to form the antifouling layer can be an organic compound or an inorganic compound. Examples of materials that bring high water repellency and oil repellency include fluorine-containing organic compounds and organosilicon compounds. Examples of the fluorine-containing organic compound include fluorocarbon, perfluorosilane, and these polymer compounds. From the viewpoint of easily improving the effect of preventing the adhesion of stains, it is preferable that the contact angle of the surface of the antifouling layer with respect to pure water is 90 degrees or more, and furthermore, it is 100 degrees or more. The method for forming the antifouling layer can be physical vapor deposition, chemical vapor growth, wet coating, etc., which are represented by evaporation or sputtering, depending on the material to be formed. The average thickness of the antifouling layer is usually about 1-50 nm, preferably 3-35 nm.

＜Ultraviolet absorption function＞ In the laminate of the present invention, the functional layer may be an ultraviolet absorbing layer having an ultraviolet absorbing function. The ultraviolet absorbing layer includes, for example, a main material selected from the group consisting of ultraviolet curable translucent resin, electron beam curable translucent resin, and thermosetting translucent resin, and an ultraviolet absorber dispersed in the main material.

＜Adhesive function＞ In the laminate of the present invention, the functional layer may be an adhesive layer having the function of adhering the optical film to other members. As the forming material of the adhesive layer, well-known materials can be used. For example, a thermosetting resin composition or a photocuring resin composition can be used. In this case, by supplying energy afterwards, the thermosetting resin composition or the photocuring resin composition can be polymerized and cured.

The adhesive layer may also be a layer called a pressure sensitive adhesive (PSA) that is attached to an object by pressing. The pressure-sensitive adhesive can be an adhesive, which is a "substance that has adhesiveness at room temperature and adheres to the material to be adhered with a lighter pressure" (JIS K 6800). It can also be a capsule adhesive. Capsule-type adhesives are "adhesives that contain specific ingredients in a protective coating (microcapsule) and can maintain stability before the coating is destroyed by appropriate means (pressure, heat, etc.)" (JIS K 6800).

<Hue adjustment function> In the laminate of the present invention, the functional layer may be a hue adjustment layer having a function of adjusting the laminate to a target hue. The hue adjusting layer is, for example, a layer containing resin and coloring agent. As the coloring agent, for example, inorganic pigments such as titanium oxide, zinc oxide, red lead, oxytitanium-based calcined pigments, ultramarine blue, cobalt aluminate, and carbon black; azo-based compounds, quinacridone-based compounds, Organic pigments such as anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, Shihlin-based compounds, and diketopyrrolopyrrole-based compounds; barium sulfate, and carbonic acid Extender pigments such as calcium; and dyes such as basic dyes, acid dyes, and mordant dyes.

The laminated system of the present invention is a laminated body of a transparent resin film and a protective film, and is a laminated body obtained in the intermediate stage before obtaining a laminated body with a functional layer. The laminated system with a functional layer includes a transparent resin film and a functional layer. For specific functions, the laminate of the present invention can effectively prevent peeling of the protective film and warpage of the laminate itself when manufacturing a laminate with a functional layer. When the protective film is peeled from the laminated body of the transparent resin film and the protective film, and the remaining transparent resin film is used together with the functional layer as necessary, it is applied to the base material of the optical member of the flexible device or the display member, or the front panel Transparency, UV resistance, and the function of exhibiting high hardness on the surface required by the time.

(Example) The present invention will be described in further detail with examples. It should be noted that the present invention is not limited to these embodiments.

＜Thickness measurement＞ The thickness of the transparent resin film and the laminate was measured using a Micrometer (manufactured by Mitutoyo Co., Ltd.).

＜Measurement of tensile modulus of elasticity＞ The "Autograph AG-IS" manufactured by Shimadzu Corporation was used to measure the tensile elastic modulus of the transparent resin film, laminate, and protective film used in the examples and comparative examples. Make a 10 mm wide sample, measure the stress-strain curve (S-S curve) at a distance of 50 mm between the chucks and a tensile speed of 10 mm/min, and calculate the tensile modulus of elasticity based on its slope.

＜Measurement of weight average molecular weight (Mw) of polyimide polymer＞ The weight average molecular weight (Mw) of polyimide and polyimide imine is measured by gel permeation chromatography (GPC), and it is calculated|required by standard polystyrene conversion. The specific measurement conditions are as follows. a. Pretreatment method Add DMF (Dimethylformamide) eluent (10 mmol/L lithium bromide solution) to the polyimide and polyimide (sample) so that the concentration becomes 2 mg/mL, It was heated at 80°C while stirring for 30 minutes. After cooling, it was filtered with a 0.45 μm membrane filter, and the solution thus obtained was used as the measurement solution. b. Measurement conditions Column: TSKgel SuperAWM-H×2＋SuperAW2500×1 (6.0 mm I.D.×150 mm×3) Eluent: DMF (add 10 mmol/L lithium bromide) Flow rate: 1.0 mL/min Detector: RI (Refractive Index, refractive index) detector Column temperature: 40℃ Injection volume: 100 μL Molecular weight standard: standard polystyrene

<Amount of residual solvent> The content of the solvent in the transparent resin film is calculated as the mass reduction rate from 120°C to 250°C obtained by thermogravimetric-differential thermal measurement (TGA), and it is set as the residual solvent amount (mass%).

Production Example 1: Preparation of polyimide-based polymer Prepare a reactor with a silicone tube, a stirring device and a thermometer, and an oil bath in the separable flask. Put 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA) 75.52 g and 2,2'-bis(trifluoromethyl)-4,4'- into the flask Diaminobiphenyl (TFMB) 54.44 g. While stirring at 400 rpm, while adding 519.84 g of N,N-dimethylacetamide (DMAc), stirring was continued until the contents of the flask became a homogeneous solution. Then, while adjusting using an oil bath so that the temperature in the container becomes 20 to 30°C, stirring is continued for a further 20 hours to react to generate polyamide 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 so that the polymer concentration became 10% by mass. Furthermore, 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, and after that, the polyimide varnish was taken out from the reaction vessel. The obtained polyimide varnish was dropped into methanol for reprecipitation, and the obtained precipitate was heated and dried to remove the solvent to obtain polyimide 1 as a solid component. GPC measurement of the obtained polyimide polymer showed that its weight average molecular weight was 360,000.

Production Example 2: Preparation of polyimide-based polymer Under a nitrogen 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 stirred at room temperature to dissolve TFMB in DMAc. Then, 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(benzyl chloride) (OBBC) was added to the flask, followed by 15.87 g (78.18 mmol) of terephthalic acid chloride (TPC), and Stir at room temperature for 1 hour. Then, 9.89 g (106.17 mmol) of 4-picoline 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, followed by stirring for 3 hours to obtain The reaction solution.

The obtained reaction liquid was cooled to room temperature, linearly poured into a large amount of methanol, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 100° C. to obtain polyimide 1. GPC measurement of the obtained polyimide 1 was performed, and as a result, its weight average molecular weight was 420,000.

Manufacturing Example 3: Preparation of silica sol An amorphous silica sol with a BET (Brunauer-Emmett-Teller, Buert) diameter (average particle size measured by the BET method) of 27 nm, prepared by the sol-gel method, was used as a raw material, and replaced by a solvent , Preparation of γ-butyrolactone (hereinafter, sometimes referred to as GBL) to replace silica sol. Filter the obtained sol with a 10 μm mesh filter to obtain GBL-substituted silica sol. The content of silica particles in the obtained GBL-substituted silica sol was 30% by mass.

Production Example 4: Production of protective film 1 Introduce nitrogen into a reaction device equipped with a stirrer, a thermometer, a reflux cooler, and a nitrogen introduction pipe, and replace the air in the reaction device with nitrogen. Thereafter, 100 parts by mass of 1-octyl acrylate, 0.2 parts by mass of 6-hydroxyhexyl acrylate, 3.5 parts by mass of N-hydroxyethyl acrylamide, 0.4 parts by mass of carboxyethyl acrylate, and polyethylene were added to the reaction device. 3 parts by mass of alcohol monoacrylate, and 60 parts by mass of ethyl acetate were added. Thereafter, 0.1 parts by mass of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and reacted at 65°C for 6 hours to obtain an acrylic copolymer solution 1 with a weight average molecular weight of 500,000.

To the acrylic copolymer solution 1 prepared as described above (where the acrylic copolymer is 100 parts by mass), 5.0 parts by mass of dimethylaminomethyl acrylate hexafluorophosphate methyl salt, KF-353 manufactured by Shin-Etsu Chemical Co., Ltd. are added (HLB (Hydrophile-Lipophile Balance) = 10 polyether-modified silicone compound) 0.1 parts by mass, 3.0 parts by mass of acetone and stirred, after which, Nippon Polyurethane Industry Co., Coronate HX (isocyanurate compound of hexamethylene diisocyanate compound) 2.0 parts by mass manufactured by Mitsui Chemicals Co., Ltd., Takenate D-14ON (isophorone diisocyanate (IPDI) addition compound) manufactured by Mitsui Chemicals Co., Ltd. ) 0.5 parts by mass, stirring and mixing, to obtain an adhesive composition. After coating the adhesive composition on a release film made of a polyethylene terephthalate (PET) film with a thickness of 18 μm coated with a silicone resin, it was dried at 90°C to remove Solvent to obtain an adhesive sheet with an adhesive layer thickness of 12 μm.

Thereafter, the adhesive sheet was transferred to the 38 μm polyethylene terephthalate (PET) film with antistatic and antifouling treatment on the opposite side of the antistatic and antifouling treatment to obtain A protective film with a laminated structure of "PET film with antistatic and antifouling treatment/adhesive layer/release film (PET film with release film containing silicone resin)". After that, the obtained protective film was aged for 7 days in an environment of 23° C. and 50% RH to obtain a protective film 1.

Production Example 5: Production of Protective Film 2 Except that the thickness of the polyethylene terephthalate (PET) film to be bonded was changed to 75 μm, the protective film 2 was obtained by the same method as in Production Example 4.

Production Example 6: Production of Transparent Resin Film 1 The polyimide 1 obtained by the above-mentioned Production Example 1 was dissolved in a mixed solvent obtained by mixing GBL and DMAc in a ratio of 1:9 at a concentration of 16.5% by mass to obtain a varnish 1. Coating the obtained varnish 1 on a polyethylene terephthalate (PET) film substrate (thickness 188 μm; COMOSHINE (registered trademark) A4100 manufactured by Toyobo Co., Ltd.) with a width of 1,000 mm by tape casting )on. Thereafter, the coated film was dried by heating at 50°C for 30 minutes and 140°C for 10 minutes at a linear speed of 0.4 m/min. Then, it was manufactured by SUN A.KAKEN CO., LTD. After bonding NSA-33T to the surface opposite to the PET substrate surface, the PET film substrate was peeled off from the film to obtain a 1,000 m roll 1. Thereafter, it was heated at 200° C. for 12 minutes to obtain a transparent resin film 1 with a thickness of 50 μm. The amount of residual solvent in the obtained transparent resin film 1 was 1% by mass. In addition, in the obtained transparent resin film, the total light transmittance was 92.5%, the haze was 0.3%, the yellowness was 1.6, and the tensile modulus of elasticity was 4 GPa.

Production Example 7: Production of Transparent Resin Film 2 The polyamide imide 1 obtained by the above-mentioned Production Example 2 was dissolved in GBL at a concentration of 10% by mass to obtain a varnish 2. Except for using the varnish 2 and changing the linear speed to 0.2 m/min, the transparent resin film 2 was obtained by the same method as the manufacture example 6. The amount of residual solvent in the obtained transparent resin film 2 was 0.8% by mass. In addition, in the obtained transparent resin film 2, the total light transmittance was 91.0%, the haze was 0.3%, the yellowness was 1.6, and the tensile modulus of elasticity was 6 GPa.

Production Example 8: Production of transparent resin film 3 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 to mix thoroughly, thereby obtaining polyamideimide Imine 1/silica particles = 60/40 (mass ratio). At this time, varnish 3 was prepared so that the solid content concentration became 11% by mass. After that, the linear speed was changed to 0.25 m/min, and except for this, the transparent resin film 3 was obtained by the same method as in Production Example 6. The total light transmittance of the transparent resin film 3 is 90.0%, the haze is 0.2%, the yellowness is 2.0, and the tensile modulus of elasticity is 7.3 GPa.

(Production of multilayer body) Example 1 The protective film 1 from which the release film was peeled off was attached to the transparent resin film 1 produced in the above-mentioned production example 6 and wound into a roll, thereby obtaining a 800 m transparent resin film roll 1.

Example 2 Except for using the protective film 2 from which the peeling film was peeled off, it carried out similarly to Example 1, and obtained the transparent resin film roll 2 of 800 m.

Example 3 The protective film 1 from which the release film was peeled off was attached to the transparent resin film 2 produced in the above-mentioned production example 7 and wound into a roll shape, thereby obtaining a 800 m transparent resin film roll 3.

Example 4 Except for using the protective film 2 from which the peeling film was peeled off, it carried out similarly to Example 3, and obtained the transparent resin film roll 4 of 800 m.

Example 5 The protective film 1 from which the release film was peeled off was attached to the transparent resin film 3 produced in the above-mentioned production example 8 and wound into a roll, thereby obtaining a 800 m transparent resin film roll 5.

Example 6 Except for using the protective film 2 from which the peeling film was peeled off, it carried out similarly to Example 5, and obtained the transparent resin film roll 6 of 800 m.

Comparative example 1 Toretec (registered trademark) N-711 (polyethylene protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedure as in Example 1 was used to obtain a 800 m transparent resin film Volume 7.

Comparative example 2 Toretec (registered trademark) 7832C (polyethylene-based protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedure as in Example 1 was used to obtain a 800 m transparent resin film roll 8 .

Comparative example 3 Toretec (registered trademark) N-711 (polyethylene protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedures as in Example 3 were used to obtain a 800 m transparent resin film Volume 9.

Comparative example 4 Toretec (registered trademark) 7832C (polyethylene-based protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedure as in Example 3 was used to obtain an 800 m transparent resin film roll 10 .

Comparative example 5 Toretec (registered trademark) N-711 (polyethylene protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedure as in Example 5 was used to obtain a 800 m transparent resin film Volume 11.

Comparative example 6 Toretec (registered trademark) 7832C (polyethylene-based protective film) manufactured by TORAY ADVANCED FILM Co., Ltd. was used as the protective film, except that the same procedure as in Example 5 was used to obtain an 800 m transparent resin film roll 12 .

For Examples 1 to 6 and Comparative Examples 1 to 6, the composition of the laminate, the tensile elastic modulus E1 (GPa) of the laminate, the tensile elastic modulus E2 (GPa) of the protective film, and the thickness T1 of the laminate (μm) and the thickness T2 (μm) of the protective film are shown in Table 1.

[Table 1] Transparent resin film Protective film E1 E2 T1 T2 Transparent resin film roll number Example 1 1 Protective film 1 3.9 2.0 101 50 1 Example 2 1 Protective film 2 4.2 2.5 138 88 2 Example 3 2 Protective film 1 4.7 2.0 99 50 3 Example 4 2 Protective film 2 4.7 2.5 137 88 4 Example 5 3 Protective film 1 5.5 2.0 101 50 5 Example 6 3 Protective film 2 5.3 2.5 138 88 6 Comparative example 1 1 Toretec N711A 2.7 0.4 79 30 7 Comparative example 2 1 Toretec 7832C 2.2 0.3 96 45 8 Comparative example 3 2 Toretec N711A 4.0 0.4 76 30 9 Comparative example 4 2 Toretec 7832C 3.3 0.3 96 45 10 Comparative example 5 3 Toretec N711A 5.1 0.4 80 30 11 Comparative example 6 3 Toretec 7832C 3.9 0.3 99 45 12

Production Example 21: Photocurable resin composition 1 28.4 parts by mass of trimethylolpropane triacrylate (A-TMPT manufactured by Shinnakamura Chemical Co., Ltd.) and 28.4 parts by mass of pentaerythritol tetraacrylate (A-TMMT manufactured by Shinnakamura Chemical Co., Ltd.) were used as photopolymerization Starting agent 1-hydroxycyclohexyl phenyl ketone (Irgacure (registered trademark) 184 manufactured by BASF Co., Ltd.) 1.8 parts by mass, lithium bisfluorosulfonamide (LiFSI manufactured by Tokyo Chemical Industry Co., Ltd.) 2.4 parts by mass Parts, 0.1 parts by mass of a leveling agent (BYK (registered trademark)-307 manufactured by BYK-Chemie Japan CO., LTD.), and 39 parts by mass of propylene glycol 1-monomethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) , A photocurable resin composition 1 was obtained.

(Evaluation) The film is unrolled from the transparent resin film roll 1, and the photocurable resin composition 1 is coated on the surface of the non-protective film 1 using a bar coater so that the thickness after drying becomes 10 μm. Thereafter, it was dried in an oven at 80°C for 3 minutes, ^{and cured by irradiating ultraviolet rays with an energy of 500 mJ/cm 2} of a high-pressure mercury lamp, thereby obtaining an optical laminate with a functional layer in the form of a film roll with a length of 400 m.

<Warpage measurement> Place the laminate in an environment with a temperature of 25°C and a humidity of 50%RH for 24 hours, then cut it into A4 size, and then place the sample on a water platform with the protective film facing the side of the stage. Measure the height of the four corners of the sample from the table top and set the average value of the four corners as the warpage of the sample. According to the amount of warpage, the judgment is made as follows. ◎: Very good: 2 mm or less ○: Good: 5 mm or less △: Slightly better: 10 mm or less ×: Bad: more than 10 mm

＜Peeling of protective film＞ Visually confirm whether or not the protective film is peeled from the transparent resin film after UV (Ultraviolet) curing, that is, whether there is peeling.

The same evaluation was performed on the transparent resin film rolls 2-12. The evaluation results are shown in Table 2 together with E1×T1 and E1/E2 of the transparent resin film roll.

[Table 2] Transparent resin film roll E1×T1 E1/E2 Warpage Peel off Example 1 1 393.9 2.0 〇 no Example 2 2 579.6 1.7 ◎ no Example 3 3 465.3 2.4 〇 no Example 4 4 643.9 1.9 ◎ no Example 5 5 555.5 2.8 〇 no Example 6 6 731.4 2.1 ◎ no Comparative example 1 7 213.3 6.8 X Have Comparative example 2 8 211.2 7.3 X Have Comparative example 3 9 302.4 10.0 X Have Comparative example 4 10 316.8 11.0 X Have Comparative example 5 11 408.0 12.8 X Have Comparative example 6 12 386.1 13.0 X Have

It can be seen from Table 2 that when the tensile elastic modulus E1 and thickness T1 of the laminate meet 350<E1×T1<1,000 (1), and the tensile elastic modulus E1 of the laminate and the tensile elastic modulus of the protective film When the number E2 satisfies 1.0≦E1/E2≦6.5 (2), there is no warpage during coating and no peeling of the protective film during curing. In the comparative examples that did not satisfy these values, warpage occurred during coating, and peeling of the protective film was also seen frequently.

The optical laminate with a functional layer obtained in Examples 1 to 6 was further laminated with a protective film on the side of the functional layer, thereby obtaining a laminate composed of two surface-layer protective films of a transparent film with a functional layer. [Industrial availability]

In the laminate of the transparent resin film and the protective film of the present invention, there is no warpage during coating, and no peeling of the protective film during curing, so that the yield rate when manufacturing the laminate with functional layers is improved, and the productivity is improved .

1: Transparent resin film 2: Protective film 2': Another protective film 3: Functional layer

FIG. 1 is a schematic cross-sectional view showing the layer structure in each step. The above steps are the steps from the formation of the transparent resin film to the state where the transparent resin film is covered by the functional layer.

1: Transparent resin film

2: Protective film

2': Another protective film

3: Functional layer

Claims (11)

A laminated body comprising a transparent resin film and a protective film, the transparent resin film comprising at least one resin selected from the group consisting of polyimide, polyimide, and polyimide The above-mentioned protective film is attached to one side of the above-mentioned transparent resin film, and The tensile elastic modulus E1 and thickness T1 of the above-mentioned laminate satisfy the formula (1), 350＜E1×T1＜1,000 (1) And the tensile elastic modulus E1 of the above laminate and the tensile elastic modulus E2 of the protective film satisfy the formula (2) 1.0≦E1/E2≦6.5 (2). Such as the laminate of claim 1, wherein the elastic modulus E1 of the laminate is 2.0 GPa or more and 10.0 GPa or less. Such as the laminate of claim 1 or 2, wherein the tensile elastic modulus E2 of the protective film is 1.5 GPa or more and 10.0 GPa or less. Such as the laminate of any one of claims 1 to 3, wherein the total light transmittance of the transparent resin film at a thickness of 50 μm is 85.0% or more. The laminate of any one of claims 1 to 4, wherein the haze of the transparent resin film at a thickness of 50 μm is 1.0% or less. The laminate according to any one of claims 1 to 5, wherein the protective film has an adhesive layer. The laminate of claim 6, wherein the adhesive layer contains acrylic resin. The laminate according to any one of claims 1 to 7, wherein a transparent resin film is used for the front panel of the flexible device. A laminated body with a functional layer, which is formed by an area layer functional layer on the side opposite to the surface in contact with the protective film included in the laminated body according to any one of claims 1 to 8. Such as the laminate with a functional layer of claim 9, wherein the functional layer is a hard coat layer. A protective film laminate, which is formed by laminating another protective film on the laminate with a functional layer as in claim 9 or 10.

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