JP2018153974A - Transparent heat resistant laminated film, transparent flexible printed wiring board, transparent electrode substrate, illumination device and organic electroluminescent display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent heat resistant laminated film capable of improving humidity and heat durable adhesion with a metal layer while keeping transparency; and a transparent flexible printed wiring board, a transparent electrode substrate, an illumination device and an organic electroluminescent display having the transparent heat resistant laminated film.SOLUTION: A transparent heat resistant laminated film 20 has a layer A 21 and a layer B 22 containing transparent heat resistant resins, and a metal layer in this order, where the layer B 22 has a small value of thermal expansion coefficient compared to the layer A 21 and has a thin layer thickness, a thermal expansion coefficient of the layer B 22 is in a range of 10-40 ppm/°C, and a yellow index value containing the layer A 21 and the layer B 22 is 3.0 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transparent heat resistant laminated film, a transparent flexible printed circuit board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device, and in particular, can improve wet heat durability adhesion with a metal layer while maintaining transparency. The present invention relates to a transparent heat resistant laminated film that can be produced.

In recent years, flexible boards have come to be used with the reduction in size and weight of electronic devices. For example, a flexible substrate is also required for illumination applications, and a film having excellent heat resistance such as a polyimide film may be used as a general flexible substrate film for LED illumination device applications (see, for example, Patent Document 1). .)
In the transparent heat-resistant laminated film, for example, since there is a problem when used for a display or the like, a resin having high transparency and a high coefficient of thermal expansion (CTE) is used.
In transparent heat-resistant laminated films, a metal layer such as a metal foil is adhered on the base film, but a three-layer base film is known to ensure adhesion between the base film and the metal layer. It has been. For example, by using a non-thermoplastic polyimide resin for the core layer and a base film using a thermoplastic polyimide resin on both surfaces, a transparent heat resistant laminated film that can be bonded to the metal layer by lamination (For example, refer to Patent Document 2).

  However, in the transparent heat resistant laminated film as described above, it was found that when the wet heat durability evaluation was performed, the metal layer was peeled off from the base film.

International Publication No. 2009/107433 JP2013-75525A

  The present invention has been made in view of the above-described problems and situations, and the problem to be solved is a transparent heat-resistant laminated film capable of improving wet heat durability adhesion with a metal layer while maintaining transparency, the transparent It is to provide a transparent flexible printed board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device provided with a heat resistant laminated film.

In order to solve the above-mentioned problems, the present inventor reduced the thermal expansion coefficient of the B layer on which the metal layer is laminated and has a higher thermal expansion coefficient than the B layer in the process of examining the cause of the above-mentioned problem. By laminating a highly transparent A layer under the B layer, it was found that adhesion peeling due to a dimensional change between the B layer and the metal layer can be improved even in wet heat durability evaluation while maintaining transparency.
That is, the said subject which concerns on this invention is solved by the following means.

1. A transparent heat-resistant laminated film having A layer and B layer containing a transparent heat-resistant resin and a metal layer in this order,
The layer B has a smaller coefficient of thermal expansion than the layer A, and the layer thickness is thin.
The thermal expansion coefficient of the B layer is in the range of 10 to 40 ppm / ° C, and
A transparent heat-resistant laminated film, wherein a yellow index value including the A layer and the B layer is 3.0 or less.

  2. The ratio of the thickness of the A layer and the B layer is in the range of A layer: B layer = 99: 1 to 67:33.

3. The layer A contains dichloromethane;
Content of the said dichloromethane is in the range of 1-800 mass ppm, The transparent heat resistant laminated | multilayer film of Claim 1 or 2 characterized by the above-mentioned.

4). The A layer contains a fluorine-based polyimide resin,
From the first item, the B layer contains a polyimide resin, and the polyimide resin has an imide group concentration in the range of 20 to 30% by mass after imidization of the polyimide precursor. The transparent heat-resistant laminated film according to any one of Items up to Item 3.

  5. A transparent flexible printed circuit board comprising the transparent heat-resistant laminated film according to any one of items 1 to 4.

  6). A transparent electrode substrate comprising the transparent heat-resistant laminated film according to any one of items 1 to 4.

  7). An illuminating device comprising the transparent heat-resistant laminated film according to any one of items 1 to 4.

  8). An organic electroluminescence display device comprising the transparent heat-resistant laminated film according to any one of items 1 to 4.

A transparent heat-resistant laminated film capable of improving wet heat durability adhesion with a metal layer while maintaining transparency by the above means of the present invention, a transparent flexible printed board provided with the transparent heat-resistant laminated film, and a transparent electrode substrate A lighting device and an organic electroluminescence display device can be provided.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
The transparent heat-resistant laminated film of the present invention has a lower coefficient of thermal expansion (CTE) of the B layer on which the metal layer is laminated, and the A layer having a higher CTE but higher transparency than the B layer is laminated below the B layer. Thus, the difference between the CTE of the B layer and the CTE of the metal layer can be reduced. As a result, when wet heat durability evaluation is performed, stress is generated due to the dimensional change of each layer between the metal layer and the base film, but the dimensional change amount of the B layer is smaller than the dimensional change amount of the A layer. The generated stress can be reduced, and the metal layer can be prevented from peeling off from the base film.

Schematic diagram of an apparatus used for co-casting according to the present invention

  The transparent heat resistant laminated film of the present invention is a transparent heat resistant laminated film having an A layer, a B layer and a metal layer containing a transparent heat resistant resin in this order, and the B layer is compared with the A layer. The thermal expansion coefficient is small, the layer thickness is thin, the thermal expansion coefficient of the B layer is in the range of 10 to 40 ppm / ° C., and the yellow index including the A layer and the B layer The value is 3.0 or less. This feature is a technical feature common to or corresponding to the claimed invention.

  As an embodiment of the present invention, the ratio of the thickness of the A layer and the B layer is in the range of A layer: B layer = 99: 1 to 67:33, from the viewpoint of durable adhesion and transparency. To preferred.

  The layer A contains dichloromethane, and the content of the dichloromethane is in the range of 1 to 800 ppm by mass, so that the solvent penetrates excessively into the layer B adjacent to the layer A, and adhesion and transparency. Can be prevented, and the adhesiveness to the B layer is good.

  The A layer contains a fluorine-based polyimide resin, the B layer contains a polyimide resin, and the polyimide resin has an imide group concentration of 20 to 30% by mass after imidizing the polyimide precursor. It is preferable in the range that it is excellent in transparency and heat resistance.

  The transparent heat-resistant laminated film of the present invention is suitably used for a transparent flexible printed board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

[Outline of Transparent Heat-Resistant Laminate Film of the Present Invention]
The transparent heat resistant laminated film of the present invention is a transparent heat resistant laminated film having an A layer and a B layer containing a transparent heat resistant resin, and a metal layer in this order. In addition, in this application, the film which consists of A layer and B layer is also called a base film.
The “transparent” of the transparent heat-resistant resin in the present invention means “transparent” when the heat-resistant laminated film is formed using the transparent heat-resistant resin and the YI (yellow index) value satisfies the following conditions. ".

<Coefficient of thermal expansion>
The layer B has a smaller coefficient of thermal expansion than the layer A, and the layer B has a thermal expansion coefficient in the range of 10 to 40 ppm / ° C. More preferably, it is in the range of 10-25 ppm / ° C.
Moreover, it is preferable that the thermal expansion coefficient of A layer is larger than 20 ppm / degrees C. The upper limit of the thermal expansion coefficient of the A layer is preferably 60 ppm / ° C.

Here, “thermal expansion coefficient (also referred to as average linear expansion coefficient)” (ppm / ° C.) of the present application means that when the temperature of the sample is changed from T ₁ to T ₂ , the length in the uniaxial direction is from L ₁ to L _If it is changed to ₂ , it means a value obtained by dividing the changed length (L ₂ −L ₁ ) by the sample length (L ₀ ) and the temperature difference (T ₂ −T ₁ ) at room temperature or 0 ° C. (See JIS-K-0129: 2005, JIS-K-7197: 1991)
Thermal expansion coefficient (ppm / ° C.) = [{(L ₂ −L ₁ ) / L ₀ } / (T ₂ −T ₁ )] × 10 ⁶

  As a thermomechanical analyzer used, for example, TMA / SS7100 (manufactured by Hitachi High-Tech Science Co., Ltd.) can be used.

A specific measurement method is, for example, that a test piece of a film having a thickness of 35 μm composed of a single A layer is set to a certain size (for example, length 20 mm, width 3 mm), and a force of 50 mN is applied to the test piece. While applying tension, the temperature was raised from 23 ° C. to Tg−50 ° C. at a heating rate of 10 ° C./min, and then the temperature was lowered to 23 ° C., and again from 23 ° C. at a heating rate of 10 ° C./min. When the temperature is raised to −50 ° C., the thermal expansion coefficient at 50 to 200 ° C. at the time of the second temperature rise is calculated by the following formula.
<Expression> Thermal expansion coefficient (ppm / ° C.) = ((Sample length at 200 ° C.) − (Sample length at 50 ° C.) / (Sample length at 23 ° C.)) / (200 ° C.-50 ° C. ) × 10 ⁶
In addition, it can measure similarly to the above about the film which consists of B layer single layer.

  The means for setting the thermal expansion coefficients of the A layer and the B layer in the above range can be achieved by adjusting the type and content of the resin contained in the A layer and the B layer. Specifically, as described later, a fluorinated polyimide resin is used as the resin of the A layer, a polyimide resin is used as the resin of the B layer, and the imide group concentration after the polyimide resin imidizes the polyimide precursor. Is preferably in the range of 20 to 30% by mass.

<Yellow index value>
A yellow index (YI) value including the A layer and the B layer is 3.0 or less. More preferably, it exists in the range of 0.3-4.0, Most preferably, it exists in the range of 0.3-2.0. The smaller the yellow index value, the better the coloration.
The yellow index value can be adjusted by selecting the composition of the transparent heat-resistant resin contained in the A layer and the B layer. To make the yellow index value 3.0 or less, as described later, the A layer The transparent heat resistant resin contained in the B layer is preferably a polyimide resin in which the A layer is a fluorine-based polyimide resin and the B layer has an imide group concentration in the range of 20 to 30% by mass.

  The yellow index value can be obtained according to YI (yellow index: yellowness index) of the film defined in JIS K 7103.

As a measuring method of the yellow index value, a sample of a base film composed of A layer and B layer is prepared, and JIS is used by using a spectrophotometer U-3300 of Hitachi High-Technologies Corporation and the attached saturation calculation program. The tristimulus values X, Y, and Z of the light source color defined in Z 8701 are obtained, and the yellow index value is obtained according to the definition of the following equation.
Yellow index value (YI value) = 100 (1.28X-1.06Z) / Y

<Layer thickness>
The layer thickness of the base film comprising the A layer and the B layer according to the present invention is preferably 200 μm or less from the viewpoints of strength, transparency and retardation (also referred to as retardation) as the base film. More preferably, it is in the range of ˜100 μm. If the layer thickness is 10 μm or more, a certain level of film strength can be secured. If the layer thickness is 100 μm or less, the printed circuit board is flexible.
In the base film, the ratio of the thicknesses of the A layer and the B layer is preferably 99: 1 to 67:33. That is, the thickness of the A layer is preferably in the range of 9 to 67 μm, and the thickness of the B layer is preferably in the range of 1 to 33 μm.

  The layer thickness can be measured by, for example, a contact type film thickness meter. In addition, the thickness can also be measured by cutting the cross section of the film using a microtome and observing the cross section with an SEM.

  Moreover, it is preferable that the base film which concerns on this invention is elongate, specifically, it is preferable that it is about 100-10000m in length, and is wound up in roll shape. The width of the base film according to the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably in the range of 1.4 to 4 m.

[Configuration of transparent heat-resistant laminated film]
<A layer and B layer>
The transparent heat resistant laminated film of the present invention is a transparent heat resistant laminated film having an A layer and a B layer containing a transparent heat resistant resin, and a metal layer in this order.
The A layer and the B layer contain a transparent heat resistant resin.

[1] Transparent heat resistant resin The transparent heat resistant resin is preferably at least one resin selected from polyimide, polyamic acid, polyarylate and polyether from the viewpoint of heat resistance and transparency. In the invention, the A layer contains a fluorine-based polyimide resin, the B layer contains a polyimide resin, and the imide group concentration after the polyimide resin imidizes the polyimide precursor is 20 to 30 mass. % Is preferable in terms of excellent transparency and heat resistance.

The imide group concentration is a value calculated by the following formula in the polyimide resin after imidizing the polyimide precursor.
(Molecular weight of imide group) / (Molecular weight of all polymers) × 100
Specifically, the imide group concentration is calculated by the following method.
The imide group density | concentration in a unit unit is calculated from the molecular weight of aromatic tetracarboxylic dianhydride and aromatic diamine. For example, in the case of a polyimide having a structure represented by the following formula (X), the imide group concentration is
Imido group molecular weight = 70.03 x 2 = 140.06
Since unit molecular weight = 894.96,
Imide group concentration (%) = (140.06) / (894.96) × 100 = 15.6%.

[1-1] Polyimide or polyamic acid The transparent heat-resistant resin according to the present invention is preferably selected from polyimide or polyamic acid, and more preferably polyimide.

The polyimide or polyamic acid used in the present invention is particularly represented by a polyimide having a repeating unit represented by the following general formula (1) (hereinafter referred to as polyimide (A)) or the following general formula (1 ′). The polyamic acid having a repeating unit (hereinafter referred to as polyamic acid (A ′)) is preferred.
In particular, the resin used for the A layer according to the present invention is preferably a fluorine-based polyimide resin in which at least one of R or Φ has a fluorine atom in the following general formula (1).
Moreover, as resin used for the B layer which concerns on this invention, as above-mentioned, it is a polyimide resin or a polyamide resin, and it is preferable that the said imide group density | concentration exists in the range of 20-30 mass%, and a polyimide resin. As for, a fluorine-type polyimide resin may be sufficient and a non-fluorine-type polyimide resin may be sufficient.

In the general formulas (1) and (1 ′), R is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, or a tetravalent aliphatic hydrocarbon group or alicyclic hydrocarbon group having 4 to 39 carbon atoms. is there. Φ is a group composed of a divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof, and —O—, At least selected from the group consisting of —SO ₂ —, —CO—, —CH ₂ —, —C (CH ₃ ) ₂ —, —OSi (CH ₃ ) ₂ —, —C ₂ H ₄ O— and —S—. One group may be contained.

  Examples of the aromatic hydrocarbon ring represented by R include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, and o-terphenyl ring. M-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, and anthra An anthrene ring etc. are mentioned.

  Examples of the aromatic heterocycle represented by R include a silole ring, furan ring, thiophene ring, oxazole ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, and oxadiazole ring. , Triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (carbazole ring) Any one or more of the carbon atoms constituting the dibenzosilole ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring. Is replaced by a nitrogen atom Substituted ring, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodi Oxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring, Examples include phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.

  Examples of the tetravalent aliphatic hydrocarbon group having 4 to 39 carbon atoms represented by R include a butane-1,1,4,4-triyl group, an octane-1,1,8,8-triyl group, Examples include decane-1,1,10,10-triyl group.

  Examples of the tetravalent alicyclic hydrocarbon group having 4 to 39 carbon atoms represented by R include cyclobutane-1,2,3,4-tetrayl group, cyclopentane-1,2,4,5. -Tetrayl group, cyclohexane-1,2,4,5-tetrayl group, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetrayl group, bicyclo [2.2.2] Octane-2,3,5,6-tetrayl group, 3,3 ′, 4,4′-dicyclohexyltetrayl group, 3,6-dimethylcyclohexane-1,2,4,5-tetrayl group, 3,6- Examples include diphenylcyclohexane-1,2,4,5-tetrayl group.

  Examples of the divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms with or without the above-described bonding group represented by Φ include groups represented by the following structural formulas.

  In the above structural formula, n represents the number of repeating units, preferably 1 to 5, and more preferably 1 to 3. X is an alkanediyl group having 1 to 3 carbon atoms, that is, a methylene group, an ethylene group, a trimethylene group, or a propane-1,2-diyl group, and a methylene group is preferable.

  Examples of the divalent alicyclic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-described bonding group represented by Φ include groups represented by the following structural formulas.

  Examples of the C2-39 divalent aromatic hydrocarbon group having or not having the above-described bonding group represented by Φ include groups represented by the following structural formulas.

  Examples of the group composed of a combination of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group represented by Φ include groups represented by the following structural formulas.

  The group represented by Φ is preferably a divalent aromatic hydrocarbon group having 2 to 39 carbon atoms having a bonding group, or a combination of the aromatic hydrocarbon group and an aliphatic hydrocarbon group. A group represented by the following structural formula is preferred.

  As described above, the polyamic acid (A ′) corresponds to a structure in which a part of the imide bond of the polyimide (A) is dissociated, and the detailed description of the polyamic acid (A ′) can be considered corresponding to the polyimide (A). Therefore, the polyimide (A) will be typically described in detail below.

  The repeating unit represented by the general formula (1) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, still more preferably 80 to 100 mol%, particularly preferably all the repeating units. 90 to 100 mol%. Further, the number of repeating units of the general formula (1) in one molecule of polyimide (A) is 10 to 2000, preferably 20 to 200. In this range, the glass transition temperature is 230 to 350 ° C. Is preferable, and it is more preferable that it is 250-330 degreeC. The glass transition temperature can be measured with a DSC apparatus (differential scanning calorimeter). For example, using a differential scanning calorimeter (DSC-6220, manufactured by Seiko Instruments Inc.), the temperature rising rate is 20 ° C. The glass transition temperature (Tg) can be determined by the intermediate glass transition temperature (Tmg) measured according to JIS K7121 (1987).

  The polyimide (A) is obtained by reacting an aromatic, aliphatic or alicyclic tetracarboxylic acid or a derivative thereof with a diamine or a derivative thereof.

  Examples of the derivative of the aliphatic or alicyclic tetracarboxylic acid include aliphatic or alicyclic tetracarboxylic acid esters, aliphatic or alicyclic tetracarboxylic dianhydrides, and the like. Of the aliphatic or alicyclic tetracarboxylic acids or derivatives thereof, alicyclic tetracarboxylic dianhydrides are preferred.

  Examples of the diamine derivative include diisocyanate and diaminodisilane. Of the diamines or derivatives thereof, diamines are preferred.

  Examples of the aliphatic tetracarboxylic acid include 1,2,3,4-butanetetracarboxylic acid. Examples of the alicyclic tetracarboxylic acid include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,4,5-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid. Bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, and the like. Can be mentioned.

  Examples of the aliphatic tetracarboxylic acid esters include monoalkyl esters, dialkyl esters, trialkyl esters, and tetraalkyl esters of the above aliphatic tetracarboxylic acids. Examples of the alicyclic tetracarboxylic acid esters include monoalkyl esters, dialkyl esters, trialkyl esters, and tetraalkyl esters of the above alicyclic tetracarboxylic acids. In addition, it is preferable that an alkyl group site | part is a C1-C5 alkyl group, and it is more preferable that it is a C1-C3 alkyl group.

  Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, 1,2 , 4,5-cyclohexanetetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] Examples include octane-2,3,5,6-tetracarboxylic dianhydride. Particularly preferred is 1,2,4,5-cyclohexanetetracarboxylic dianhydride. In general, a polyimide having an aliphatic diamine as a constituent component forms a strong salt between the polyamic acid, which is an intermediate product, and the diamine. Therefore, in order to increase the molecular weight, a solvent having a relatively high salt solubility (for example, cresol). N, N-dimethylacetamide, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) are preferably used. However, even with polyimides containing aliphatic diamine as a constituent, when 1,2,4,5-cyclohexanetetracarboxylic dianhydride is used as a constituent, the salt of polyamic acid and diamine is bound by a relatively weak bond. Therefore, it is easy to obtain a high molecular weight and a flexible film can be easily obtained.

  Other examples include 4,4′-biphthalic anhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 4- (2, 5-Dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3- Cyclohexene-1,2-dicarboxylic anhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,4'-oxydiphthalic anhydride, 3,4,9,10-perylenetate Carboxylic dianhydride (Pigment Red 224) 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride tricyclo [6.4.0.02,7] dodecane- 1,8: 2,7-tetracarboxylic dianhydride and the like can be used.

  Aromatic, aliphatic or alicyclic tetracarboxylic acids or their derivatives may be used alone or in combination of two or more. Further, other tetracarboxylic acids or derivatives thereof (particularly dianhydrides) may be used in combination as long as the solvent solubility of the polyimide, the flexibility of the film, the thermocompression bonding property, and the transparency are not impaired.

  Examples of such other tetracarboxylic acids or derivatives thereof include pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 2, 2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (2,3-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1 , 3,3,3-hexafluoropropane, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (3,4-dicarboxy) Phenyl) sulfone, bis (3,4-dicarboxyphenyl) ether, bis (2,3-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2 ′, , 3'-benzophenonetetracarboxylic acid, 4,4- (p-phenylenedioxy) diphthalic acid, 4,4- (m-phenylenedioxy) diphthalic acid, 1,1-bis (2,3-dicarboxyphenyl) ) Aromatic tetracarboxylic acids such as ethane, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane and their derivatives (particularly dianhydrides); ethylenetetracarboxylic acid, etc. And an aliphatic tetracarboxylic acid having 1 to 3 carbon atoms and derivatives thereof (particularly dianhydrides).

  In the method for producing a transparent heat-resistant film of the present invention, it is preferable to contain a polyimide or polyamic acid having a fluorene skeleton in order to improve the coloration peculiar to the conventional polyimide. The polyimide or polyamic acid having the fluorene skeleton is preferably formed from a diamine or a derivative thereof and an acid anhydride or a derivative thereof, and either the diamine or the acid anhydride is a compound having a fluorene skeleton.

  In addition, the fluorene skeleton as used in the field of this invention means the following structures.

  A commercially available polyimide film has a problem that it is colored from yellow to brown due to absorption in the visible light region derived from intermolecular or intramolecular charge transfer interactions. In addition, the film has a problem that the process load is high and the moldability is low, for example, heat treatment at a high temperature is required to form the film. Specifically, the polyimide forming the film has low solubility in a solvent, and it is difficult to form a film using the polyimide as it is. Therefore, after using the solvent solution of the polyamic acid which is the polyimide precursor to form a film-like coating film by casting to a support, the coating film is heat-treated at a high temperature of about 400 ° C. It is necessary to imidize the polyamic acid in the film to obtain a film made of polyimide. Therefore, there was a problem that coloring was strong.

  In the present invention, it is preferable to use a polyimide or polyamic acid having a fluorene skeleton, thereby improving the coloring problem and obtaining a transparent heat-resistant laminated film.

  Among acid anhydrides, examples of acid anhydrides having a fluorene skeleton include 9,9-bis (3,4-dicarboxyphenyl) fluorenic acid dianhydride, 9,9-bis [4- (3,4). -Dicarboxyphenoxy) phenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-phenylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-phenylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-phenylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -2-phenylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-me Ruphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-methylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4- Dicarboxyphenoxy) -2-methylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -2-methylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-Dicarboxyphenoxy) -3-ethylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-ethylphenyl] fluorenic acid Anhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-ethylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy)- -Ethylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-propylphenyl] fluoric dianhydride, 9,9-bis [4- (2, 3-dicarboxyphenoxy) -3-propylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-propylphenyl] fluorenic dianhydride, 9,9 -Bis [4- (2,3-dicarboxyphenoxy) -2-propylphenyl] fluoric acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-butylphenyl] fluorene Acid dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-butylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (3,4-dicarboxyl) Enoxy) -2-butylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -2-butylphenyl] fluorenic dianhydride, 9,9-bis [4 -(3,4-Dicarboxyphenoxy) -3-tert-butylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-tert-butylphenyl] fluorene Acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-tert-butylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (2,3-di Carboxyphenoxy) -2-t-butylphenyl] fluorenic dianhydride, and the like. Among these aromatic bis (ether anhydride) compounds, 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic dianhydride, 9,9-bis [4- (3 , 4-Dicarboxyphenoxy) -3-phenylphenyl] fluorenic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-phenylphenyl] fluorenic dianhydride, 9-bis [4- (3,4-dicarboxyphenoxy) -3-methylphenyl] fluoric acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-methylphenyl] And fluoric acid dianhydride.

  Among them, 9,9-bis (3,4-dicarboxyphenyl) fluoric acid dianhydride or 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluoric acid dianhydride should be used. Is preferable from the viewpoints of heat resistance and transparency.

  The diamine may be an aromatic diamine, an aliphatic diamine, or a mixture thereof. In the present invention, the term “aromatic diamine” refers to a diamine in which an amino group is directly bonded to an aromatic ring, and an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or any other part of its structure. A substituent (for example, a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.) may be contained. The term “aliphatic diamine” refers to a diamine in which an amino group is directly bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group or other substituent ( For example, a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.) may be included.

  Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, benzidine, o-tolidine, m-tolidine, bis (trifluoromethyl) benzidine, Octafluorobenzidine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3, , 3'-difluoro-4,4'-diaminobiphenyl, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diamino Diphenylmethane, 4,4'-diaminodiphenylsulfone, 3,4'-diamy Diphenylsulfone, 4,4'-diaminobenzophenone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (2-methyl-4-aminophenoxy) phenyl) propane 2,2-bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2-Methyl-4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) hexafluoropropane, 4,4'- Bis (4-aminophenoxy) biphenyl, 4,4'-bis (2-methyl-4-aminophenoxy) biphenyl, 4,4'-bis (2,6- Methyl-4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (2-methyl-4-aminophenoxy) ) Phenyl) sulfone, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) ether, bis (4- (2-methyl-4-) Aminophenoxy) phenyl) ether, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) ether, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (2-methyl-) 4-aminophenoxy) benzene, 1,4-bis (2,6-dimethyl-4-aminophenoxy) benzene, 1,3-bis (4-amino) Nophenoxy) benzene, 1,3-bis (2-methyl-4-aminophenoxy) benzene, 1,3-bis (2,6-dimethyl-4-aminophenoxy) benzene, 2,2-bis (4-amino) Phenyl) propane, 2,2-bis (2-methyl-4-aminophenyl) propane, 2,2-bis (3-methyl-4-aminophenyl) propane, 2,2-bis (3-ethyl-4-) Aminophenyl) propane, 2,2-bis (3,5-dimethyl-4-aminophenyl) propane, 2,2-bis (2,6-dimethyl-4-aminophenyl) propane, 2,2-bis (4 -Aminophenyl) hexafluoropropane, 2,2-bis (2-methyl-4-aminophenyl) hexafluoropropane, 2,2-bis (2,6-dimethyl-4-aminophenyl) hex Fluoropropane, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α '-Bis (2,6-dimethyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis ( 4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2,6-dimethyl- 4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,3-diisopropylbenzene, 9,9-bis (4-aminophenyl) full Orene, 9,9-bis (2-methyl-4-aminophenyl) fluorene, 9,9-bis (2,6-dimethyl-4-aminophenyl) fluorene, 1,1-bis (4-aminophenyl) cyclo Pentane, 1,1-bis (2-methyl-4-aminophenyl) cyclopentane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclopentane, 1,1-bis (4-aminophenyl) ) Cyclohexane, 1,1-bis (2-methyl-4-aminophenyl) cyclohexane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclohexane, 1,1-bis (4-aminophenyl) 4-methyl-cyclohexane, 1,1-bis (4-aminophenyl) norbornane, 1,1-bis (2-methyl-4-aminophenyl) norbornane, 1,1 Bis (2,6-dimethyl-4-aminophenyl) norbornane, 1,1-bis (4-aminophenyl) adamantane, 1,1-bis (2-methyl-4-aminophenyl) adamantane, 1,1-bis (2,6-dimethyl-4-aminophenyl) adamantane, 1,4-phenylenediamine, 3,3′-diaminobenzophenone, 2,2-bis (3-aminophenyl) hexafluoropropane, 3-aminobenzylamine, 9,9-bis (4-amino-3-fluorophenyl) fluorene, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] sulfur 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, bis (2-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, 1,3-bis (3-amino) Propyl) tetramethyldisiloxane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-ethylenedianiline, 4,4'-methylenebis (cyclohexylamine), 4,4'-methylenebis (2,6-diethylaniline), 4,4'-methylenebis (2-methylcyclohexylamine) and the like.

  Examples of the aliphatic diamine include ethylene diamine, hexamethylene diamine, polyethylene glycol bis (3-aminopropyl) ether, polypropylene glycol bis (3-aminopropyl) ether, 1,3-bis (aminomethyl) cyclohexane, 1,4. -Bis (aminomethyl) cyclohexane, m-xylylenediamine, p-xylylenediamine, 1,4-bis (2-amino-isopropyl) benzene, 1,3-bis (2-amino-isopropyl) benzene, isophorone Diamine, norbornane diamine, siloxane diamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3, , 3 ' 5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, 2,3-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) -bicyclo [2 2.1] heptane, 2,6-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,2-bis (4,4'-diaminocyclohexyl) propane, 2,2-bis (4 , 4'-diaminomethylcyclohexyl) propane and the like.

  As diisocyanate which is a diamine derivative, the diisocyanate obtained by making the said aromatic or aliphatic diamine and phosgene react is mentioned, for example.

  Examples of diaminodisilanes that are diamine derivatives include trimethylsilylated aromatic or aliphatic diamine obtained by reacting the above aromatic or aliphatic diamine with chlorotrimethylsilane.

  The above diamines and derivatives thereof may be arbitrarily mixed and used, but the amount of diamine in them is preferably 50 to 100 mol%, more preferably 80 to 100 mol%.

Of the diamines or derivatives thereof, the diamine having a fluorene skeleton or a derivative thereof is preferably an aromatic diamine, such as 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9. -Bis [4- (4-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- ( 2-Aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4- Amino-2-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-ethylphenoxy) -3- Enylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-i-propylphenoxy) ) -3-Phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-) 3-tert-butylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4 -(4-Amino-3-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-2-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-4-methyl) Phenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-5-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-6) -Methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-2-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3 -Amino-4-trifluoromethylphenoxy) -3-phenylphenyl] fluorene,
9,9-bis [4- (3-amino-5-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-6-trifluoromethylphenoxy) -3 -Phenylphenyl] fluorene, 9,9-bis [4- (2-amino-3-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-4-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-5-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-6-methyl) Phenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-3-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, , 9-bis [4- (2-amino-4-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) -3- Phenylphenyl] fluorene, 9,9-bis [4- (2-amino-6-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) ) Phenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) phenyl] fluorene ,
9,9-bis [4- (4-amino-2-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) phenyl] fluorene, 9-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-methylphenoxy) phenyl] fluorene, 9,9-bis [ 4- (4-amino-3-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4 -Amino-3-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-tert-butylphenoxy) phenyl] fluorene, 9,9-bis [4- ( -Amino-3-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-3-methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4) -Methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-methylphenoxy) phenyl] Fluorene, 9,9-bis [4- (2-amino-3-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-ethylphenoxy) phenyl] fluorene, 9,9- Bis [4- (2-amino-5-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-ethylphenoxy) phenyl] fur Orene, 9,9-bis [4- (2-amino-3-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-n-propylphenoxy) phenyl] fluorene, 9-bis [4- (2-amino-3-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-i-propylphenoxy) phenyl] fluorene, 9,9- Bis [4- (2-amino-5-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-i-propylphenoxy) phenyl] fluorene, 9 , 9-bis [4- (2-amino-3-tert-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-tert-butylphenoxy) phenyl] fluorene, 9,9 -Bis [4- (2-amino-5-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-3-trifluoromethylphenoxy) phenyl] fluorene,
9,9-bis [4- (2-amino-4-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) phenyl] fluorene, 9-bis [4- (2-amino-6-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-methylphenyl] fluorene, 9, 9-bis [4- (4-amino-2-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-methylphenyl] Fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t Butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4- Amino-2-methylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- ( 4-amino-2-n-propylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-ethylphenyl] fluorene, 9,9 -Bis [4- (4-amino-2-tert-butylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethyl) Noxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino) -2-ethylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-n-propylphenyl] fluorene, 9,9- Bis [4- (4-amino-2-i-propylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3-n -Propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino- 2-methylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-n-propylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-i-propylphenyl Fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoro) Methylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-tert-butylphenyl] fluorene, 9,9-bis [ -(4-Amino-2-ethylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-t-butylphenyl] fluorene 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-tert-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) ) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- ( 4-amino-2-methylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-trifluoromethylphenyl] fluor 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propyl) Phenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-pro Pyrphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4 -(4-amino-2-tert-butylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5-dimethylphenyl ] Fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy)- 3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- 4-Amino-2-i-propylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3,5-diethylphenyl] fluorene 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy)- 3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-Amino-2-n-propylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy)- 3, 5 Di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-trifluoromethylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5- Di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- ( 4-amino-2-n-propylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5- Di-i-propylphenyl] Fluorene, 9,9-bis [4- (4-amino-2-tert-butylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2 -Trifluoromethylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-di-t-butylphenyl] Fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n -Propylphenoxy) -3,5-di-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-di-t-butylphenyl] Fluorene, 9,9-bis [4- (4 Amino-2-tert-butylphenoxy) -3,5-di-tert-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5-di- t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4 -Amino-2-ethylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3,5-di ( Trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4 − ( -Amino-2-tert-butylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5- Di (trifluoromethyl) phenyl] fluorene,
9,9-bis [4- (2-amino-3-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-4-methylphenoxy) -3-methylphenyl] Fluorene, 9,9-bis [4- (2-amino-5-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-6-methylphenoxy) -3-methyl Phenyl] fluorene, 9,9-bis [4- (2-amino-3-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-4-trifluoromethyl) Phenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [ -(2-amino-6-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-methylphenoxy) -3-methylphenyl] fluorene, 9,9 -Bis [4- (3-amino-4-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-methylphenoxy) -3-methylphenyl] fluorene, 9 , 9-bis [4- (3-amino-6-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-ethylphenoxy) -3-methylphenyl] fluorene 9,9-bis [4- (3-amino-4-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-n) -Propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-4-n-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3 -Amino-5-n-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-n-propylphenoxy) -3-methylphenyl] fluorene, 9,9- Bis [4- (3-amino-2-i-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-4-i-propylphenoxy) -3-methylphenol Enyl] fluorene, 9,9-bis [4- (3-amino-5-i-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-i-propyl) Phenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-tert-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino -4-tert-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-tert-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [ 4- (3-amino-6-tert-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-trifluoromethylphenoxy) -3-methylphenyl] fur Orene, 9,9-bis [4- (3-amino-4-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-trifluoromethylphenoxy) -3-methylphenyl] fluorene, and the like.

  The polyimide or polyamic acid having the fluorene skeleton includes diamine or a derivative thereof, and an acid anhydride or a derivative thereof, and the diamine includes 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- It is preferably either amino-3-methylphenyl) fluorene or 9,9-bis (3-fluoro-4-aminophenyl) fluorene, and the acid anhydride is 9,9-bis (3,4- From the viewpoint of improving non-coloring properties, it is preferably either dicarboxyphenyl) fluorene dianhydride or 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic dianhydride. .

  The polyamic acid is obtained by polymerizing at least one of the tetracarboxylic acids and at least one of the diamines in a suitable solvent.

  The polyamic acid ester is diesterified by ring-opening the tetracarboxylic dianhydride with an alcohol such as methanol, ethanol, isopropanol, or n-propanol, and the obtained diester is converted into the above-mentioned diester in an appropriate solvent. It can be obtained by reacting with a diamine compound. Furthermore, the polyamic acid ester can also be obtained by esterifying the carboxylic acid group of the polyamic acid obtained as described above by reacting with the alcohol as described above.

  The reaction between the tetracarboxylic dianhydride and the diamine compound can be carried out under conventionally known conditions. There are no particular limitations on the order of addition or addition method of the tetracarboxylic dianhydride and the diamine compound. For example, a polycarboxylic acid can be obtained by sequentially adding a tetracarboxylic dianhydride and a diamine compound to a solvent and stirring at an appropriate temperature.

  The amount of the diamine compound is usually 0.8 mol or more, preferably 1 mol or more with respect to 1 mol of tetracarboxylic dianhydride. On the other hand, it is 1.2 mol or less normally, Preferably it is 1.1 mol or less. The yield of the polyamic acid obtained can be improved by making the quantity of a diamine compound into such a range.

  The concentration of the tetracarboxylic dianhydride and the diamine compound in the solvent is appropriately set according to the reaction conditions and the viscosity of the polyamic acid solution. For example, the total mass of the tetracarboxylic dianhydride and the diamine compound is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more with respect to the total amount of the solution, while usually 70%. It is not more than mass%, preferably not more than 30 mass%. By setting the amount of the reaction substrate in such a range, the polyamic acid can be obtained at a low cost and in a high yield.

  The reaction temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, and is usually 100 ° C. or lower, preferably 80 ° C. or lower. The reaction time is not particularly limited but is usually 1 hour or longer, preferably 2 hours or longer, and is usually 100 hours or shorter, preferably 24 hours or shorter. By performing the reaction under such conditions, the polyamic acid can be obtained at a low cost and in a high yield.

  Examples of the polymerization solvent used in this reaction include hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene and mesitylene; carbon tetrachloride, methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene, diethylene Halogenated hydrocarbon solvents such as chlorobenzene and fluorobenzene; ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane and methoxybenzene; ketone solvents such as acetone and methyl ethyl ketone; N, N-dimethylformamide, N, N Amide solvents such as dimethylacetamide and N-methyl-2-pyrrolidone; Aprotic polar solvents such as dimethyl sulfoxide and γ-butyrolactone; Complexes such as pyridine, picoline, lutidine, quinoline and isoquinoline System solvent; phenol solvents such as phenol and cresol, but and the like, but is not particularly limited. As a polymerization solvent, only 1 type can also be used and 2 or more types of solvents can also be mixed and used.

  Moreover, you may control a polymerization reaction by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction.

  As will be described later, the polyimide is obtained by heat-treating a film in which the polyamic acid solution is cast, or by casting a polyamic acid solution mixed with a ring-closing catalyst onto the support for imidization. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylenediamine, and heterocyclic tertiary amines such as isoquinoline, pyridine and picoline, and are selected from heterocyclic tertiary amines. It is preferred to use at least one amine. The content of the ring-closing catalyst relative to the polyamic acid is preferably in a range where the content (mol) of the ring-closing catalyst / the content (mol) of the polyamic acid is 0.5 to 8.0.

  As the polyamic acid or polyimide constituted as described above, those having a weight average molecular weight of 30,000 to 1,000,000 are used from the viewpoint of forming a film.

  Moreover, the polyamic acid may be imidized at the time of casting, and it is preferable that the imidation ratio at the time of casting is 10 to 100%. Here, the imidization rate can be obtained from the peak obtained by Fourier transform infrared spectroscopy by the following formula.

Formula (A): (C / D) × 100 / (E / F)
In the above formula (A), C represents the absorption peak height of 1370 cm ⁻¹ of the polyamic acid or polyimide dope, D represents the absorption peak height of 1500 cm ⁻¹ of the polyamic acid or polyimide dope, and E Represents the absorption peak height of 1370 cm ⁻¹ of the polyimide film, and F represents the absorption peak height of 1500 cm ⁻¹ of the polyimide film.

  By setting the imidization rate of the polyamic acid at the time of casting to 10 to 100%, a polyimide film having a lower elastic modulus than the method of imidizing after forming a cast film using a polyamic acid having an imidization rate of 0% Can be obtained.

[1-2] Polyarylate The transparent heat resistant resin according to the present invention may be selected from polyarylate.

<Polyarylate>
The polyarylate contains at least an aromatic dialcohol component unit and an aromatic dicarboxylic acid component unit.

(Aromatic dialcohol component unit)
The aromatic dialcohol for obtaining the aromatic dialcohol component unit is preferably a bisphenol represented by the following general formula (2), more preferably a bisphenol represented by the following general formula (2 ′).

L in the general formulas (2) and (2 ′) is a divalent organic group. The divalent organic group is preferably a single bond, an alkylene group, —S—, —SO—, —SO ₂ —, —O—, —CO— or —CR ₁ R ₂ — (R ₁ and R ₂ are To form an aliphatic ring or an aromatic ring.

  The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, and an isopropylidene group. The alkylene group may further have a substituent such as a halogen atom or an aryl group.

R ₁ and R ₂ of —CR ₁ R ₂ — are bonded to each other to form an aliphatic ring or an aromatic ring. The aliphatic ring is preferably an aliphatic hydrocarbon ring having 5 to 20 carbon atoms, and preferably a cyclohexane ring which may have a substituent. An aromatic ring is a C6-C20 aromatic hydrocarbon ring, Preferably it is a fluorene ring which may have a substituent. Examples of —CR ₁ R ₂ — forming a cyclohexane ring which may have a substituent include cyclohexane-1,1-diyl group, 3,3,5-trimethylcyclohexane-1,1-diyl group and the like. included. Examples of —CR ₁ R ₂ — forming a fluorene ring which may have a substituent include a fluorenediyl group represented by the following general formula.

  R in the general formulas (2) and (2 ′) is independently an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. n is independently an integer of 0 to 4, preferably an integer of 0 to 3.

  Examples of bisphenols in which L is an alkylene group include 1,1-bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-methyl-2 -Hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4- Hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA), etc. Is included. Among them, 2,2-bis (4-hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl- Isopropylidene-containing bisphenols such as 4-hydroxyphenyl) propane (TMBPA) are preferred.

Examples of bisphenols in which L is —S—, —SO— or —SO ₂ — include bis (4-hydroxyphenyl) sulfone, bis (2-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4 -Hydroxyphenyl) sulfone (TMBPS), bis (3,5-diethyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, Bis (4-hydroxyphenyl) sulfide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3,5-diethyl-4-hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) Sulfide, bis (3-ethyl-4-hydroxyphenyl) sulfide, 2,4-dihydride Carboxymethyl diphenyl sulfone and the like. Examples of bisphenols where L is —O— include 4,4′-dihydroxydiphenyl ether; examples of bisphenols where L is —CO— include 4,4′-dihydroxydiphenyl ketone. .

Examples of bisphenols in which L is —CR ₁ R ₂ — and R ₁ and R ₂ are bonded to each other to form an aliphatic ring include 1,1-bis (4-hydroxyphenyl) cyclohexane (BPZ) And bisphenols having a cyclohexane skeleton such as 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BPTMC).

Examples of bisphenols in which L is —CR ₁ R ₂ — and R ₁ and R ₂ are bonded to each other to form an aromatic ring include 9,9-bis (3-methyl-4-hydroxyphenyl) Bisphenols having a fluorene skeleton such as fluorene (BCF) and 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene (BXF) are included.

  The aromatic dialcohol component constituting the polyarylate may be one kind or two or more kinds.

Among these, from the viewpoint of increasing the solubility of the resin in the solvent or increasing the adhesion of the transparent heat-resistant laminated film to the metal when applied to a flexible printed circuit board, for example, a sulfur atom (—S Bisphenols containing —, —SO— or —SO ₂ —) are preferred. From the viewpoint of enhancing the heat resistance of the film, for example, bisphenols containing a sulfur atom in the main chain and bisphenols having a cycloalkylene skeleton are preferred. From the viewpoint of reducing the birefringence of the film or improving the wear resistance, bisphenols having a fluorene skeleton are preferred.

  Bisphenols having a cyclohexane skeleton and bisphenols having a fluorene skeleton are preferably used in combination with bisphenols containing an isopropylidene group. In that case, the content ratio of the bisphenol having a cyclohexane skeleton or the bisphenol having a fluorene skeleton and the bisphenol having an isopropylidene group is 10/90 to 90/10 (molar ratio), preferably 20/80 to 80/20 (molar ratio).

  The polyarylate may further contain an aromatic polyhydric alcohol component unit other than the aromatic dialcohol component as long as the effects of the present invention are not impaired. Examples of the aromatic polyhydric alcohol component include the compounds described in paragraph [0015] of Japanese Patent No. 4551503. Specifically, tris (4-hydroxyphenyl) methane, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, 2,3, 4,4′-tetrahydroxybenzophenone, 4- [bis (4-hydroxyphenyl) methyl] -2-methoxyphenol, tris (3-methyl-4-hydroxyphenyl) methane and the like are included. The content ratio of these aromatic polyhydric alcohol component units can be appropriately set according to the required characteristics, but is 5 for example with respect to the total of the aromatic dialcohol component unit and the other aromatic polyhydric alcohol component units. It can be less than mol%.

<Aromatic dicarboxylic acid component unit>
The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid component unit is preferably terephthalic acid, isophthalic acid or a mixture thereof.

  From the viewpoint of enhancing the mechanical properties of the film, a mixture of terephthalic acid and isophthalic acid is preferable. The content ratio of terephthalic acid and isophthalic acid is preferably in the range of terephthalic acid / isophthalic acid = 90/10 to 10/90 (molar ratio), more preferably in the range of 70/30 to 30/70, still more preferably 50 / A range of 50. When the content ratio of terephthalic acid is in the above range, a polyarylate having a sufficient degree of polymerization is easily obtained, and a film having sufficient mechanical properties is easily obtained.

  The polyarylate may further contain an aromatic dicarboxylic acid component unit other than terephthalic acid and isophthalic acid as long as the effects of the present invention are not impaired. Examples of such aromatic dicarboxylic acid components include orthophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, 4,4'-dicarboxydiphenyl ether, bis (p-carboxyphenyl) alkane, 4,4'- Dicarboxyphenyl sulfone and the like are included. The content ratio of aromatic dicarboxylic acid component units other than terephthalic acid and isophthalic acid is appropriately set according to the required properties, but the total of terephthalic acid component, isophthalic acid component unit and other aromatic dicarboxylic acid component units For example, it can be 5 mol% or less.

<Glass-transition temperature>
The glass transition temperature of the polyarylate is preferably in the range of 260 to 350 ° C, more preferably in the range of 265 to 300 ° C, and still more preferably in the range of 270 to 300 ° C.

  Similarly, the glass transition temperature of polyarylate is measured according to JIS K7121 (1987). Specifically, using a DSC 6220 manufactured by Seiko Instruments Inc. as a measuring device, it can be measured under the conditions of a 10 mg polyarylate sample and a heating rate of 20 ° C./min.

  The glass transition temperature of polyarylate is adjusted by the type of aromatic dialcohol component constituting the polyarylate. In order to increase the glass transition temperature, for example, it is preferable to include “units derived from bisphenols containing a sulfur atom in the main chain” as aromatic dialcohol component units.

<Intrinsic viscosity>
The intrinsic viscosity of the polyarylate, at 25 ° C., is preferably 0.3~1.0cm ³ / g, more preferably 0.4~0.9cm ³ / g, 0.45~0.8cm ³ / g is more preferable, and more preferably 0.5 to 0.7 cm ³ / g. When the intrinsic viscosity of polyarylate is 0.3 cm ³ / g or more, the molecular weight of the resin composition tends to be a certain level or more, and a film having sufficient mechanical properties and heat resistance is easily obtained. When the intrinsic viscosity of polyarylate is 1.0 cm ³ / g or less, it is possible to suppress an excessive increase in the solution viscosity during film formation.

Intrinsic viscosity can be measured according to ISO1628-1. Specifically, a solution in which a polyarylate sample is dissolved in 1,1,2,2-tetrachloroethane so as to have a concentration of 1 g / cm ³ is prepared. The intrinsic viscosity of this solution at 25 ° C. is measured using an Ubbelohde type viscosity tube.

  The polyarylate production method may be a known method, preferably an interface in which an aromatic dicarboxylic acid halide dissolved in an organic solvent incompatible with water and an aromatic dialcohol dissolved in an alkaline aqueous solution are mixed. This is a polymerization method (W. M. EARECKSON, J. Poly. Sci. XL 399, 1959, Japanese Patent Publication No. 40-1959).

  The content of polyarylate is 50% by mass or more, preferably 60% by mass or more, and more preferably 80% by mass or more with respect to the whole polyarylate film.

[1-3] Polyether The transparent heat-resistant resin according to the present invention may be selected from polyethers.

  The polyether according to the present invention includes a structural unit represented by the following general formula (3) (hereinafter also referred to as “structural unit (3)”) and a structural unit represented by the following general formula (4) (hereinafter “structure”). It is preferable to have at least one structural unit (i) selected from the group consisting of “unit (4)”. For this reason, the polyether (I) having the structural unit (i), which will be described later, is excellent in coloring resistance, heat resistance and light transmittance. Further, since the polyether (II) having a structural unit (i) and having a specific molecular weight, which will be described later, has few low molecular weight components, it is further excellent in coloring resistance, heat resistance and light transmittance.

In general formula (3), R < ¹ > -R < ⁴ > shows a C1-C12 monovalent organic group each independently. a to d each independently represent an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

  The monovalent organic group having 1 to 12 carbon atoms includes a monovalent hydrocarbon group having 1 to 12 carbon atoms and 1 to 1 carbon atoms including at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. And 12 monovalent organic groups.

  Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include a linear or branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and 6 to 12 carbon atoms. An aromatic hydrocarbon group etc. are mentioned.

  The linear or branched hydrocarbon group having 1 to 12 carbon atoms is preferably a linear or branched hydrocarbon group having 1 to 8 carbon atoms, and a linear or branched carbon group having 1 to 5 carbon atoms. A hydrogen group is more preferable.

  Specific examples of the linear or branched hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, and n-pentyl. Group, n-hexyl group and n-heptyl group.

  As said C3-C12 alicyclic hydrocarbon group, a C3-C8 alicyclic hydrocarbon group is preferable, and a C3-C4 alicyclic hydrocarbon group is more preferable.

  Preferable specific examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; cyclobutenyl group, cyclopentenyl group and cyclohexenyl group. A cycloalkenyl group is mentioned. The bonding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic ring.

  Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group, and a naphthyl group. The bonding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

  Examples of the organic group having 1 to 12 carbon atoms including an oxygen atom include an organic group composed of a hydrogen atom, a carbon atom and an oxygen atom, and among them, a total carbon composed of an ether bond, a carbonyl group or an ester bond and a hydrocarbon group. Preferable examples include organic groups of formulas 1 to 12.

  Examples of the organic group having 1 to 12 carbon atoms having an ether bond include an alkoxy group having 1 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, an alkynyloxy group having 2 to 12 carbon atoms, and 6 to 12 carbon atoms. And an aryloxy group having 2 to 12 carbon atoms and the like. Specific examples include a methoxy group, an ethoxy group, a propoxy group, an isopropyloxy group, a butoxy group, a phenoxy group, a propenyloxy group, a cyclohexyloxy group, and a methoxymethyl group.

  Moreover, as a C1-C12 organic group which has a carbonyl group, a C2-C12 acyl group etc. can be mentioned. Specific examples include an acetyl group, a propionyl group, an isopropionyl group, and a benzoyl group.

  As a C1-C12 organic group which has an ester bond, a C2-C12 acyloxy group etc. are mentioned. Specific examples include an acetyloxy group, a propionyloxy group, an isopropionyloxy group, and a benzoyloxy group.

  Examples of the organic group having 1 to 12 carbon atoms including a nitrogen atom include an organic group consisting of a hydrogen atom, a carbon atom and a nitrogen atom, and specifically, a cyano group, an imidazole group, a triazole group, a benzimidazole group and a benzine. A triazole group etc. are mentioned.

  Examples of the organic group having 1 to 12 carbon atoms including an oxygen atom and a nitrogen atom include an organic group consisting of a hydrogen atom, a carbon atom, an oxygen atom and a nitrogen atom. Specifically, an oxazole group, an oxadiazole group, Examples thereof include a benzoxazole group and a benzoxadiazole group.

As R < ¹ > -R < ⁴ > in the said General formula (3), a C1-C12 monovalent hydrocarbon group is preferable, A C6-C12 aromatic hydrocarbon group is more preferable, A phenyl group is further more preferable. .

In the general formula ^(4), R 1 to R ⁴ and a~d have the same meanings as ^R 1 to R ⁴ and a~d each independently the general formula (3), Y represents a single bond, —SO ₂ — or> C═O, R ⁷ and R ⁸ each independently represent a halogen atom, a monovalent organic group having 1 to 12 carbon atoms or a nitro group, and m represents 0 or 1. . However, when m is 0, R ⁷ is not a cyano group. g and h each independently represent an integer of 0 to 4, preferably 0.

  Examples of the monovalent organic group having 1 to 12 carbon atoms include the same organic groups as the monovalent organic group having 1 to 12 carbon atoms in the general formula (3).

  In the polyether, the molar ratio of the structural unit (3) to the structural unit (4) (however, the total of the structural unit (3) + the structural unit (4) is 100) is an optical property. From the viewpoint of heat resistance and mechanical properties, the structural unit (3): structural unit (4) is preferably in the range of 50:50 to 100: 0, and the structural unit (3): structural unit (4) = 70. Is more preferably in the range of 30 to 100: 0, and further preferably in the range of structural unit (3): structural unit (4) = 80: 20 to 100: 0.

  Here, the mechanical properties refer to properties such as tensile strength, breaking elongation and tensile elastic modulus of the polyether.

  The polyether may further have at least one structural unit selected from the group consisting of a structural unit represented by the following general formula (5) and a structural unit represented by the following general formula (6). Good. It is preferable that the polyether has such a structural unit because the mechanical properties of the film containing the polyether are improved.

In the general formula (5), R ⁵ and R ⁶ each independently represent a monovalent organic group having 1 to 12 carbon atoms, and Z represents a single bond, —O—, —S—, —SO ₂ —. ,> C═O, —CONH—, —COO—, or a divalent organic group having 1 to 12 carbon atoms, and n represents 0 or 1. e and f each independently represent an integer of 0 to 4, preferably 0.

  Examples of the monovalent organic group having 1 to 12 carbon atoms include the same organic groups as the monovalent organic group having 1 to 12 carbon atoms in the general formula (3).

  The 012 valent organic group having 1 to 12 carbon atoms includes a divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 12 carbon atoms, an oxygen atom, and a nitrogen atom. A divalent organic group having 1 to 12 carbon atoms containing at least one atom selected from the above, and a divalent organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. And halogenated organic groups.

  Examples of the divalent hydrocarbon group having 1 to 12 carbon atoms include a linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and Examples thereof include a bivalent aromatic hydrocarbon group having 6 to 12 carbon atoms.

  Examples of the linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms include methylene group, ethylene group, trimethylene group, isopropylidene group, pentamethylene group, hexamethylene group and heptamethylene group.

  Examples of the divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms include cycloalkylene groups such as cyclopropylene group, cyclobutylene group, cyclopentylene group and cyclohexylene group; cyclobutenylene group, cyclopentenylene group and cyclohexylene. And cycloalkenylene groups such as a selenylene group. The bonding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic ring.

  Examples of the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenylene group, a naphthylene group, and a biphenylene group. The bonding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

  Examples of the divalent halogenated hydrocarbon group having 1 to 12 carbon atoms include a linear or branched divalent halogenated hydrocarbon group having 1 to 12 carbon atoms and a divalent halogenated fat having 3 to 12 carbon atoms. Examples thereof include a cyclic hydrocarbon group and a divalent halogenated aromatic hydrocarbon group having 6 to 12 carbon atoms.

  Examples of the linear or branched divalent halogenated hydrocarbon group having 1 to 12 carbon atoms include a difluoromethylene group, a dichloromethylene group, a tetrafluoroethylene group, a tetrachloroethylene group, a hexafluorotrimethylene group, a hexachlorotrimethylene group, Examples include a hexafluoroisopropylidene group and a hexachloroisopropylidene group.

  As the divalent halogenated alicyclic hydrocarbon group having 3 to 12 carbon atoms, at least a part of the hydrogen atoms exemplified in the divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms is a fluorine atom. , A group substituted with a chlorine atom, a bromine atom or an iodine atom.

  As the divalent halogenated aromatic hydrocarbon group having 6 to 12 carbon atoms, at least a part of the hydrogen atoms exemplified in the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms is a fluorine atom, chlorine And a group substituted with an atom, a bromine atom or an iodine atom.

  The divalent organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom is a hydrogen atom and a carbon atom and an oxygen atom and / or a nitrogen atom. And a divalent organic group having 1 to 12 carbon atoms having an ether bond, a carbonyl group, an ester bond or an amide bond and a hydrocarbon group.

  Specifically, the divalent halogenated organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of oxygen atom and nitrogen atom is selected from the group consisting of oxygen atom and nitrogen atom. Examples include a group in which at least a part of the hydrogen atoms exemplified in the divalent organic group having 1 to 12 carbon atoms containing at least one atom is substituted with a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. .

Z in the general formula (5) is preferably a single bond, —O—, —SO ₂ —,> C═O or a divalent organic group having 1 to 12 carbon atoms, and a divalent group having 1 to 12 carbon atoms. Or a divalent halohydrocarbon group having 1 to 12 carbon atoms is more preferable, and the divalent hydrocarbon group having 1 to 12 carbon atoms is a divalent alicyclic group having 3 to 12 carbon atoms. A hydrocarbon group is preferred.

In the general formula (6), R ⁷ , R ⁸ , Y, m, g, and h are each independently synonymous with R ⁷ , R ⁸ , Y, m, g, and h in the general formula (4). ^There, R ^5, R 6, Z, n, e and f have the same meanings as respectively ^R 5 in independently the general formula ^{(5), R 6, Z} , n, e and f. When m is 0, R ⁷ is not a cyano group.

  In the polyether, the molar ratio of the structural unit (5) to the structural unit (6) (however, the sum of both ((5) + (6)) is 100) is optical characteristics and heat resistance. And from the viewpoint of mechanical properties, the range is preferably (5) :( 6) = 50: 50 to 100: 0, and (5) :( 6) = 70: 30 to 100: 0. Is more preferable, and (5) :( 6) = 80: 20 to 100: 0 is more preferable.

  The polyether preferably contains the structural unit (5) and the structural unit (6) in an amount of 70 mol% or more in the total structural units from the viewpoint of optical properties, heat resistance and mechanical properties, and 95 mol in the total structural units. It is more preferable that it contains more than%.

<Polyether synthesis method>
Examples of the polyether include a compound represented by the following general formula (7) (hereinafter also referred to as “compound (7)”) and a compound represented by the following general formula (8) (hereinafter “compound (8)”). It can be obtained by reacting the component (C) containing at least one compound selected from the group consisting of: and the component (D) containing a compound represented by the following general formula (9).

  In the general formula (7), X independently represents a halogen atom, preferably a fluorine atom.

In the general formula (8), R ⁷ , R ⁸ , Y, m, g, and h are each independently synonymous with R ⁷ , R ⁸ , Y, m, g, and h in the general formula (4). Yes, X is independently synonymous with X in the general formula (7). However, when m is 0, R ⁷ is not a cyano group.

In the general formula (9), R ^a independently represents a hydrogen atom, a methyl group, an ethyl group, an acetyl group, a methanesulfonyl group or a trifluoromethylsulfonyl group, and among them, a hydrogen atom is preferable. In general formula (9), R ^{1 to} R ⁴ and a to d are independently synonymous with R ^{1 to} R ⁴ and a to d in general formula (3).

  Specific examples of the compound (7) include 2,6-difluorobenzonitrile, 2,5-difluorobenzonitrile, 2,4-difluorobenzonitrile, 2,6-dichlorobenzonitrile, and 2,5-dichloro. Mention may be made of benzonitrile, 2,4-dichlorobenzonitrile and their reactive derivatives. In particular, 2,6-difluorobenzonitrile and 2,6-dichlorobenzonitrile are preferably used from the viewpoint of reactivity and economy. These compounds can be used in combination of two or more.

  Specific examples of the compound represented by the general formula (9) (hereinafter also referred to as “compound (9)”) include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis ( 3-phenyl-4-hydroxyphenyl) fluorene, 9,9-bis (3,5-diphenyl-4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9 -Bis (4-hydroxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-cyclohexylphenyl) fluorene, and reactive derivatives thereof. Among the above-mentioned compounds, 9,9-bis (4-hydroxyphenyl) fluorene and 9,9-bis (3-phenyl-4-hydroxyphenyl) fluorene are preferably used. These compounds can be used in combination of two or more.

  Specific examples of the compound (8) include 4,4′-difluorobenzophenone, 4,4′-difluorodiphenylsulfone, 2,4′-difluorobenzophenone, 2,4′-difluorodiphenylsulfone, 2,2 '-Difluorobenzophenone, 2,2'-difluorodiphenylsulfone, 3,3'-dinitro-4,4'-difluorobenzophenone, 3,3'-dinitro-4,4'-difluorodiphenylsulfone, 4,4'- Dichlorobenzophenone, 4,4'-dichlorodiphenylsulfone, 2,4'-dichlorobenzophenone, 2,4'-dichlorodiphenylsulfone, 2,2'-dichlorobenzophenone, 2,2'-dichlorodiphenylsulfone, 3,3 ' -Dinitro-4,4'-dichlorobenzophenone and 3,3'-di Toro-4,4'-dichlorodiphenyl sulfone and the like. Among these, 4,4′-difluorobenzophenone and 4,4′-difluorodiphenyl sulfone are preferable. These compounds can be used in combination of two or more.

  It is preferable that at least one compound selected from the group consisting of the compound (7) and the compound (8) is contained in an amount of 80 to 100 mol%, and 90 to 100 mol% is contained in 100 mol% of the component (C). More preferably.

  Moreover, it is preferable that a component (D) contains the compound (henceforth "compound (10)") represented by the following general formula (10) as needed.

  Compound (9) is preferably contained in 100 to 100 mol% of component (D), more preferably 50 to 100 mol%, more preferably 80 to 100 mol%, and more preferably 90 to 100 mol%. More preferably.

In the general formula (10), R ⁵ , R ⁶ , Z, n, e, and f are each independently synonymous with R ⁵ , R ⁶ , Z, n, e, and f in the general formula (5). And R ^a is independently synonymous with R ^a in the general formula (9).

  Examples of the compound (10) include hydroquinone, resorcinol, 2-phenylhydroquinone, 4,4′-biphenol, 3,3′-biphenol, 4,4′-dihydroxydiphenylsulfone, 3,3′-dihydroxydiphenylsulfone, 4 , 4′-dihydroxybenzophenone, 3,3′-dihydroxybenzophenone, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy) Phenyl) -1,1,1,3,3,3-hexafluoropropane and reactive derivatives thereof. These compounds can be used in combination of two or more.

  Among the above-mentioned compounds, resorcinol, 4,4′-biphenol, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy) Phenyl) -1,1,1,3,3,3-hexafluoropropane is preferred, and 4,4′-biphenol is suitably used from the viewpoint of reactivity and mechanical properties.

  More specifically, the polyether can be synthesized by the following method (I ′) or method (II ′). Among these, by using the method (I ′), a polyether having a low molecular weight component having the above structural unit, having a specific weight average molecular weight, and having a polystyrene-reduced molecular weight by GPC of a certain molecular weight or less. Can be easily obtained.

  In the method (I ′), the component (D) and an alkali metal compound are reacted to obtain an alkali metal salt of the component (D), and the mixture after the step (a) and the component (C) ) And the step (b) of reacting the alkali metal salt obtained in step (a) with the component (C).

  Specifically, in step (a), an alkali metal salt such as compound (8) or compound (10) is obtained, and in step (b), a polyether having the structural unit (i) is obtained.

  In the steps (a) and (b), it is preferable to perform each reaction in the presence of a solvent.

  In the method (II ′), the reaction between the component (D) and the alkali metal compound is performed in the presence of the component (C).

  In this method (II ′), the alkali metal salt of component (D) reacts with component (C) to obtain the polyether.

  In the method (II ′), the reaction is preferably performed in the presence of a solvent.

In the case of producing the polyether by the method (I ′) or the method (II ′), for example,
It is preferable to increase the sum of the concentrations of component (C) and component (D) in the reaction system (component (C) + component (D) + solvent blending amount). Specifically, the sum of the concentrations of component (C) and component (D) before the start of the reaction is in the range of 20 to 50% by mass with respect to 100% by mass of the total amount of component (C), component (D) and solvent. It is preferable that it is in the range of 24 to 35% by mass.

  Since the sum of the concentrations of the component (C) and the component (D) in the reaction system is in the above range, the molecular weight distribution is narrow and the proportion of low molecular weight components having a molecular weight of 5000 or less is small. A polyether with low content can be obtained. For this reason, by using the polyether, it is possible to obtain a film having excellent light resistance, in particular, excellent light transmittance in which coloring by heating is suppressed.

  Examples of the alkali metal compound used in the reaction include alkali metals such as lithium, potassium and sodium; alkali metal hydrides such as lithium hydride, potassium hydride and sodium hydride; lithium hydroxide, potassium hydroxide and sodium hydroxide And alkali metal carbonates such as lithium carbonate, potassium carbonate and sodium carbonate; alkali metal hydrogen carbonates such as lithium hydrogen carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate. These can be used alone or in combination of two or more.

  In the alkali metal compound, the amount of metal atoms in the alkali metal compound is usually 1 to 3 times equivalent, preferably 1.1 to 2 times equivalent, and more preferably with respect to all —O—Ra in the component (D). Is used in an amount of 1.2 to 1.5 times equivalent.

  Examples of the solvent that can be used for the reaction include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyllactone, sulfolane. , Dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, diphenyl sulfone, diphenyl ether, benzophenone, dialkoxybenzene (alkoxy group having 1 to 4 carbon atoms) and trialkoxybenzene (alkoxy group having 1 to 4 carbon atoms) Etc. can be used. Among these solvents, polar solvents having a high dielectric constant such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenylsulfone and dimethylsulfoxide are particularly preferably used.

  Further, in the reaction, a solvent azeotropic with water such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole and phenetole can be further used.

  The proportion of component (C) and component (D) used is such that component (C) is preferably in the range of 45 to 55 mol% when the total of component (C) and component (D) is 100 mol%, More preferably, it is in the range of 50 to 52 mol%, more preferably more than 50 mol% and not more than 52 mol%, and component (D) is preferably in the range of 45 to 55 mol%, more preferably 48 to 50 mol%. More preferably, it is 48 mol% or more and less than 50 mol%.

  Moreover, reaction temperature becomes like this. Preferably it is 60-250 degreeC, More preferably, it is the range of 80-200 degreeC. The reaction time is preferably in the range of 15 minutes to 100 hours, more preferably 1 hour to 24 hours.

<Physical properties of polyethers>
The polyether (I) is a weight in terms of polystyrene measured using an HLC-8220 GPC apparatus (column: TSKgel α-M, developing solvent: tetrahydrofuran (hereinafter also referred to as “THF”)) manufactured by Tosoh Corporation. The average molecular weight (Mw) is preferably in the range of 5000 to 500000, more preferably in the range of 15000 to 400000, and still more preferably in the range of 30000 to 300000.

The polyether (II) was measured using a Tosoh Co., Ltd. HLC-8220 type GPC apparatus (column: SuperH2000 and SuperH4000, guard column: column connected with SuperH-L, developing solvent: THF), in terms of polystyrene. The weight average molecular weight (Mw) is preferably in the range of 2.5 × 10 ^{4 to} 5.0 × 10 ⁵ , more preferably in the range of 5.0 × 10 ^{4 to} 4.0 × 10 ⁵ , More preferably, it is the range of 7.0 * 10 < ⁴ > -3.0 * 10 < ⁵ >.

Further, the polyether preferably has an amount (ratio) of a low molecular weight component having a polystyrene-equivalent molecular weight of 5.0 × 10 ³ or less calculated by GPC based on an integral molecular weight distribution curve by GPC, It is 5.0% or less, more preferably 3.5% or less.

  When the molecular weight of the polyether and its distribution are within the above ranges, the polyether is excellent in coloring resistance, particularly coloring resistance even when exposed to high temperatures. For this reason, the film containing polyether (II) is further excellent in light transmittance, especially even when exposed to high temperatures.

The amount of the low molecular weight component having a polystyrene-equivalent molecular weight of 5.0 × 10 ³ or less is specifically determined by the Tosoh H HLC-8220 GPC apparatus (column: SuperH2000 and SuperH4000, guard column: SuperH- L, developing solvent: THF, detector: UV254 nm, flow rate: 0.6 ml / min), integrated value in chromatogram of components eluted before the elution time of polystyrene standard sample with molecular weight of 5.0 × 10 ³ And an integral value in a chromatogram of a component eluted after the elution time of a polystyrene standard sample having a molecular weight of 5.0 × 10 ³ can be calculated.

  The polyether has a thermal decomposition temperature measured by thermogravimetric analysis (TGA) of preferably 400 ° C. or higher, more preferably 425 ° C. or higher, and further preferably 450 ° C. or higher.

[2] Solvent When producing a transparent heat resistant laminated film using the transparent heat resistant resin according to the present invention, a low boiling point solvent having a boiling point of 80 ° C. or lower is used as a main solvent as a solvent for dissolving the transparent heat resistant resin. Is preferred.

  Here, “used as a main solvent” means that if the solvent is a mixed solvent, the low boiling point solvent according to the present invention is used in an amount of 55% by mass or more, preferably 70% by mass or more. It is preferably 80% by mass or more, particularly preferably 90% by mass or more. Of course, if it is used alone, it becomes 100% by mass.

  Solvents useful for forming a resin solution (dope) when a transparent heat resistant resin is produced by a solution casting film forming method may be used as long as they dissolve the transparent heat resistant resin and other additives at the same time. For example, as a chlorinated solvent, dichloromethane, as a non-chlorinated solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafur B-1-propanol, nitroethane, methanol, ethanol, n- propanol, iso- propanol, n- butanol, sec- butanol, tert- butanol and the like.

  Examples of the low boiling point solvent having a boiling point of 80 ° C. or less according to the present invention include dichloromethane (40 ° C.), ethyl acetate (77 ° C.), methyl ethyl ketone (79 ° C.), tetrahydrofuran (66 ° C.), acetone (56. And at least one selected from 1,3-dioxolane (75 ° C.) as a main solvent (the parentheses each represent a boiling point).

  Moreover, as a solvent contained in the case of a mixed solvent, as long as it can dissolve the transparent heat-resistant resin according to the present invention, it can be used within a range that does not impair the effects of the present invention. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramide, Tetramethylene sulfone, dimethyl sulfoxide, m-cresol, phenol, p-chlorophenol, 2-chloro-4-hydroxytoluene, diglyme, triglyme, tetraglyme, dioxane, γ-butyrolactone, dioxolane, cyclopentanone, epsilon caprolactam, chloroform Etc. can be used In it, it may be used in combination of two or more thereof. In addition to these solvents, a poor solvent such as hexane, heptane, benzene, toluene, xylene, chlorobenzene, or o-dichlorobenzene may be used to the extent that the transparent heat resistant resin according to the present invention does not precipitate.

In the A layer constituting the transparent heat-resistant resin of the present invention, the A layer contains dichloromethane, and the content of dichloromethane is preferably in the range of 1 to 800 ppm by mass, and is 1 to 75 ppm by mass. It is more preferable.
If it is 800 mass ppm or less, the solvent does not permeate excessively into the B layer adjacent to the A layer, and the adhesiveness and transparency with the B layer become good. Moreover, if it is 1 mass ppm or more, since the dichloromethane remains moderately, adhesiveness with B layer adjacent to A layer will become favorable.
The amount of dichloromethane residual solvent in the A layer is defined by the following formula (Z).
Formula (Z)
Residual solvent amount (%) = (mass before heat treatment of casting film or film−mass after heat treatment of casting film or film) / (mass after heat treatment of casting film or film) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

[3] Additives Various additives can be added to the dope containing the transparent heat resistant resin according to the present invention. Additives that can be used are described below.

  A heat conductive filler may be added to the dope containing the transparent heat resistant resin according to the present invention within a range not impairing the effects of the present invention. Thereby, the heat conductivity of a transparent heat resistant laminated film can be raised.

  The thermally conductive filler is preferably a highly thermally conductive filler, and specifically includes aluminum, copper, nickel, silica, diamond, alumina, magnesia, beryllia, boron nitride, aluminum nitride, silicon nitride, and silicon carbide. The filler shape is not particularly limited, such as a spherical or plate-like material, or a needle shape. Among these, at least one filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, and magnesia is preferable.

  Further, for the purpose of improving the slipperiness of the film surface, it is also preferable to use fine particles of an inorganic compound or fine particles of a resin. Examples of fine particles of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silicic acid Examples thereof include magnesium and calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle size of the fine particles is preferably in the range of 5 to 400 nm, and more preferably in the range of 10 to 300 nm. These may be mainly contained as secondary aggregates having a particle size in the range of 0.05 to 0.3 μm. If the particles have an average particle size in the range of 80 to 400 nm, the primary particles are not aggregated. It is also preferable that it is contained.

  The content of these fine particles in the film is preferably in the range of 0.01 to 1% by mass, and particularly preferably in the range of 0.05 to 0.5% by mass.

  In the case of a film having a multilayer structure formed by a co-casting method, it is preferable to contain fine particles of this addition amount on the surface.

  Silicon dioxide fine particles are commercially available, for example, under the trade names Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (Nippon Aerosil Co., Ltd.). it can.

  Zirconium oxide fine particles are commercially available, for example, under the names of Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of resin fine particles include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) Are commercially available and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the haze of the film low.

  Moreover, you may add a dehydrating agent to dope containing transparent heat resistant resin. Specific examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride, but acetic anhydride and / or anhydrous Benzoic acid is preferred. Further, the content of the dehydrating agent with respect to the transparent heat resistant resin is preferably in the range where the content of dehydrating agent (mole) / the content of transparent heat resistant resin (mole) is 0.1 to 5.0. In this case, a gelation retarder such as acetylacetone may be used in combination.

  Moreover, you may add surfactant, such as a fluorine type and a polysiloxane type, to dope containing transparent heat resistant resin, for example. When a surfactant is added, a film with good surface smoothness can be easily obtained. A commercially available product may be used as the surfactant, and examples of the fluorosurfactant include a mega-fac (registered trademark) series manufactured by DIC Corporation and a footer such as Neos Corporation's Footgent (registered trademark) series. Gent (registered trademark) 251, 212MH, 250, 222F, 212D, FTX-218, and the like. Examples of the polysiloxane surfactant include BYK-307, BYK-315, BYK-320, BYK-325, BYK-330, BYK-331, BYK-332, BYK-333, BYK manufactured by BYK-Chemie Japan Co., Ltd. -344 and the like.

  Moreover, you may add antioxidant, such as a phenol type, sulfur type, phosphoric acid type, and phosphorous acid type, to dope containing transparent heat resistant resin, for example.

Various other functional materials may be added to the dope containing the transparent heat resistant resin. Various functional materials include, for example, conductive materials such as carbon nanotubes and nano metal materials, ferroelectric materials such as barium titanate, and phosphors such as ZnS: Ag, ZnS: Cu, and Y ₂ O ₂ S: Eu. UV absorbers and the like.

  Further, a phosphorus flame retardant may be added to the dope containing a transparent heat resistant resin. Thereby, a flame retardance can be provided to a transparent heat resistant laminated film. As the phosphorus flame retardant, for example, ammonium polyphosphate, phosphate ester, condensed phosphate ester, phenoxyphosphazene compound, phosphate ester amide, and the like can be used. Among these phosphorus flame retardants, it is preferable to use a phenoxyphosphazene compound. As the phenoxyphosphazene compound, for example, SPS-100 manufactured by Otsuka Chemical Co., Ltd. can be used. Although a flame retardant can be imparted by mixing a halogen type flame retardant, it is preferable to use a phosphorus-based flame retardant.

[4] Imidization treatment of film When a cast film is formed using polyamic acid, a film containing polyimide can be produced by imidizing the obtained film.

When the film is subjected to appropriate heat treatment, imidization in the polymer chain molecules and between the polymer chain molecules proceeds to improve the mechanical properties. However, as the heat treatment is performed, the optical film using polyimide changes in the absorption wavelength. The color changes with color. In particular, in a film using a thin polyimide of 4.0 to 15.0 μm, the higher the L ^* value, the thinner the color, so the horizontal unevenness due to thickness unevenness is difficult to see, but the appearance is good. Since the progress of imidization is not sufficient, mechanical properties such as flex resistance and breaking strength of the film are deteriorated. On the other hand, if the L ^* value is too low, the color contrast due to thickness unevenness will become clear and the horizontal unevenness will be worsened, and the film using polyimide will partially carbonize and become brittle. The characteristics are significantly reduced. For the above reasons, in the method for producing a film using the polyimide according to the present invention, it is good to maintain good mechanical properties when the L ^* value is 30 to 55, and more preferably, the L ^* value is 38 to 55. 54 is preferable.

The L ^* value of the film was measured using SM-7-CH manufactured by Suga Test Instruments. About each sample divided into 5 in the film width direction, the range of 30 mm x 30 mm centering on the center position of the width direction was cut out and measured, and it was set as the 5-point average value. In addition, since the sensitivity of a detector becomes dull and the appropriate evaluation cannot be performed when the film thickness becomes thin, the L value is a minimum of 1 film for a film thickness of 50 μm or more, and 50 μm or more for a film of less than 50 μm. It is a value measured by overlapping the number of sheets.

Regarding a heat treatment method for obtaining a film having an L ^* value of 30 to 55, for example, a method of adjusting the heat treatment amount using a known means such as hot air or an electric heater (for example, an infrared heater). Can be mentioned.

  In the method for producing a film using the polyimide according to the present invention, a solution of a polyamic acid not containing a ring-closing catalyst and a dehydrating agent is cast, formed into a film, heated and dried on the support, and then the film from the support. Can be used, and a thermal ring closure method in which imidization is performed by drying and heat treatment at a high temperature can be used. In addition, a solution of a polyamic acid containing a ring-closing catalyst and a dehydrating agent is cast to form a film, and after partially imidizing on the support to form a film, the film is peeled off from the support. Alternatively, a chemical ring closure method in which heat drying / imidization and heat treatment are performed can also be used. As the ring-closing catalyst, the above-mentioned tertiary amine or the like can be used.

  In the thermal ring closure method, heat treatment can be performed by using, for example, an infrared heater.

  As the infrared heater, for example, a heater main body formed so that a filament is surrounded by an inner tube is covered with an outer tube, and a cooling fluid can be circulated between the heater main body and the outer tube. The filament is energized and heated to 700 to 1200 ° C., and emits infrared rays having a peak at a wavelength near 3 μm. The inner tube and the outer tube are made of quartz glass, borosilicate crown glass, or the like, and function as a filter that passes infrared light having a wavelength of 3.5 μm or less and absorbs infrared light having a wavelength exceeding 3.5 μm. Such infrared heaters irradiate the film with infrared light having a wavelength of 3.5 μm or less through an inner tube or an outer tube when infrared light having a peak near 3 μm is emitted from the filament. By irradiating with infrared rays having this wavelength, the mixed solvent in the film can be efficiently evaporated and the polyamic acid in the film can be imidized. The inner tube and the outer tube absorb infrared rays having a wavelength exceeding 3.5 μm, but are cooled by the cooling fluid flowing through the flow path, so that the temperature can be maintained below the ignition point of the mixed solvent evaporating from the film. Is possible.

  In the method for producing a film using the polyimide according to the present invention, any of the above ring closure methods may be adopted, but the chemical ring closure method requires equipment for containing a ring closure catalyst and a dehydrating agent in the polyamic acid solution. However, it can be said to be a more preferable method in that a film having self-supporting properties can be obtained in a short time.

<Metal layer>
The transparent heat resistant laminated film of the present invention has an A layer, a B layer and a metal layer containing the transparent heat resistant resin described above in this order.
The metal layer varies depending on the use of the transparent heat-resistant laminated film. In the case of a transparent flexible printed circuit board, the metal layer is preferably a copper foil from the viewpoint of cost reduction, but aluminum, gold, silver, aluminum Other metal foils such as nickel and tin may be used.
Moreover, in the case of a transparent electrode substrate use, silver nanowire, a metal mesh (silver, copper), etc. other than ITO are used as a metal layer (transparent conductive layer) as a metal layer.

[5] Method for producing transparent heat-resistant laminated film A specific example of the method for producing a transparent heat-resistant laminated film will be described below.

As a manufacturing method of the transparent heat resistant laminated film of the present invention,
(1) A dope for forming the A layer and a dope for forming the B layer are prepared, and a base film composed of the A layer and the B layer is produced by co-casting these two kinds of dopes. A method of further forming a metal layer on the B layer of the base film;
(2) A dope for forming the A layer and a dope for forming the B layer are prepared, and these two kinds of dopes are respectively formed as single films to form the A layer and the B layer, respectively. , A method of producing a base film composed of the A layer and the B layer by laminating the A layer and the B layer via an adhesive, and further forming a metal layer on the B layer of the base film,
Is mentioned.

The method (1) will be described in detail.
As the method of (1), a step of adjusting a dope in which the transparent heat-resistant resin contained in the A layer is dissolved in a solvent and a dope in which the transparent heat-resistant resin contained in the B layer is dissolved in the solvent (dope) Preparation step), a step of casting the two types of dopes prepared in the dope adjusting step on the support (casting step) to form a casting membrane (also referred to as a web), and the casting membrane It is preferable to have the process (peeling process) which peels from the said support body. In addition, a step of evaporating the solvent from the cast film on the support (solvent evaporation step), a step of drying the obtained film (first drying step), a step of stretching the film (stretching step), and after stretching A step of further drying the film (second drying step), a step of winding up the obtained base film consisting of the A layer and the B layer (winding step), and a step of imidizing the film by heat treatment if necessary It is preferable to be performed by (heating step) or the like. By forming a metal layer further on the B layer of the base film thus obtained, the transparent heat-resistant laminated film of the present invention is produced.

  Hereinafter, each step will be specifically described.

[5-1] Dope preparation step As described above, the dope preparation step is a step of preparing at least two types of dopes having different formulations, each of which contains a transparent heat-resistant resin dissolved in a solvent. The above-mentioned low boiling point solvent having a boiling point of 80 ° C. or lower is used as the main solvent. At that time, in order to prepare at least two kinds of dopes having different formulations, each of which has a transparent heat resistant resin dissolved in a solvent, it may be dissolved in the same solvent or in different solvents. However, from the viewpoint of avoiding the influence of the mixing of the solvents between the layers, it is preferable to dissolve in the same solvent.

  Thereafter, the prepared dope is guided to a filter by a liquid feed pump or the like and filtered.

  By filtering the dope at a temperature of the boiling point of the low-boiling solvent at 1 atm + 5 ° C. or more, gelled foreign substances in the dope are removed. A preferable temperature range is 45 to 120 ° C, more preferably 45 to 70 ° C, and further preferably 45 to 55 ° C.

[5-2] Casting film forming step In this step, the two prepared dopes are co-cast on a support to form a casting membrane.

  In the present invention, the following apparatus and method are preferably used as the co-casting.

  FIG. 1 schematically shows a part of an apparatus used for co-casting according to the present invention.

  The A layer and the B layer constituting the transparent heat resistant laminated film of the present invention are obtained by laminating dopes (dope 1 and dope 2) by co-casting, and in FIG. The example which uses and forms the base film of 2 layer structure is demonstrated.

  As shown in the figure, the co-casting has a plurality of slits 13 and 14 in the base portion 11 of the co-casting die 10, and is simultaneously formed on the metal support 16 from the slits 13 and 14 for the A layer. By casting the dope 1 (17) and the B layer dope 2 (18), a multilayer web (casting film) 20 having a configuration in which the B layer 22 is provided on the A layer 21 is formed.

  The multilayer structure web 20 is then evaporated to form a film, which is peeled off from the metal support 16 to form a base film composed of the A layer and the B layer.

  The surface temperature of the metal support is preferably 10 to 70 ° C., and the temperature of the solution is preferably 25 to 60 ° C. Further, the temperature of each solution is preferably the same as or higher than the temperature of the support.

  Although the more preferable range of the temperature of a metal support depends on the solvent to be used, it is 20 to 60 ° C, and the more preferable range of the solution temperature is 30 to 50 ° C.

  Casting may be performed by preparing a plurality of dopes and casting the plurality of dopes on a smooth band or drum as a support.

In this case, two or more kinds of dopes may be cast on the support at the same time, or separately on the support. In the case of the sequential casting method in which casting is performed separately, the dope on the support side can be cast first and dried to some extent on the support, and then overlaid on the support.
These methods, which are formed by co-casting or sequential casting, differ from the method of coating on a dried film, and the boundary between layers of the laminated structure becomes unclear, and the laminated structure is clear by observing the cross section. There is a feature that there is a case where there is no separation, there is an effect of improving the adhesion between each layer.

  As the co-casting, a known co-casting method can be used. For example, a film may be produced by casting and laminating a dope containing a transparent heat-resistant resin from a plurality of casting openings provided at intervals in the traveling direction of the metal support. The methods described in JP-A Nos. 158414, 1-122419, and 11-198285 can be applied. Further, the film may be formed by casting a dope containing a transparent heat-resistant resin from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61- No. 947245, JP-A No. 61-104413, JP-A No. 61-158413 and JP-A No. 6-134933.

  The metal support in casting (cast) preferably has a mirror-finished surface, and the support is a stainless steel belt or a drum whose surface is plated with a casting, or a metal support such as a stainless steel belt or a stainless steel belt. Is preferably used. The cast width can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, and more preferably in the range of 2 to 2.8 m. Note that the support may not be made of metal.

  The running speed of the metal support is not particularly limited, but is usually 5 m / min or more, preferably 10 to 180 m / min, particularly preferably 80 to 150 m / min. As the traveling speed of the metal support increases, entrained gas is more likely to be generated, and the occurrence of thickness unevenness due to external disturbance becomes significant.

  The traveling speed of the metal support is the moving speed of the outer surface of the metal support.

  The die has a shape that becomes gradually narrower toward the discharge port in a vertical cross section with respect to the width direction. In general, the die usually has tapered surfaces on the downstream side and the upstream side in the lower traveling direction, and a discharge port is formed in a slit shape between the tapered surfaces. A die made of metal is preferably used, and specific examples include stainless steel, titanium, and the like. In the present invention, when manufacturing films having different thicknesses, it is not necessary to change to dies having different slit gaps.

  It is preferable to use a pressure die that can adjust the slit shape of the die portion of the die and easily make the thickness uniform. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. Even when films with different thicknesses are continuously manufactured, the discharge rate of the dies is maintained at a substantially constant value. Therefore, when a pressure die is used, conditions such as extrusion pressure and shear rate are also substantially reduced. Maintained at a constant value. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and laminated.

The amount of dope discharged from the die is preferably 200 to 720 g / m ² , more preferably 400 to 650 g / m ² . In the present invention, even when films having different thicknesses are continuously produced, it is preferable that the dope discharge amount from the die is maintained at a substantially constant value within the above range. When the discharge amount is 200 g / m ² or more, the cast film is less susceptible to disturbances such as vibration and wind, and thus thickness unevenness can be sufficiently prevented. When the discharge amount is 720 g / m ² or less, the shrinkage does not occur excessively, and the thickness unevenness due to the shrinkage does not occur, so that the thickness unevenness can be sufficiently prevented.

[5-3] Solvent evaporation step The solvent evaporation step is a pre-drying step which is performed on the metal support and the cast film is heated on the metal support to evaporate the solvent.

  In order to evaporate the solvent, for example, a method of blowing heated air from the casting membrane side and the back side of the metal support by a dryer, a method of transferring heat from the back side of the metal support by a heating liquid, a method of transferring heat from the front and back by radiant heat Etc. A method of appropriately selecting and combining them is also preferable. The surface temperature of the metal support may be the same as a whole or may vary depending on the position.

  In the present invention, the drying of the multilayer structure web on the metal support is carried out at a temperature of (T-1) ° C. or lower when the boiling point of the low boiling point solvent according to the present invention is T ° C. This is a more preferable embodiment from the viewpoint of suppressing diffusion of the heat-resistant resin and remarkably suppressing mixing of materials at the layer interface. Preferably it is (T-5) degrees C or less, More preferably, it is (T-10) degrees C or less. Accordingly, the temperature of the heated air when the heated air is blown by the dryer is preferably in the range of 10 to 70 ° C.

  In the method of heating the metal support, a higher temperature is preferable because the drying speed of the (cast film) of the multilayer web can be increased. However, if the temperature is too high, the cast film is foamed or the flatness is deteriorated. Therefore, it is preferable to adjust appropriately depending on the resin or solvent used.

  In the solvent evaporation step, it is preferable to dry the cast film until the residual solvent amount is 10 to 150% by mass from the viewpoint of peelability of the cast film and transportability after peeling.

  In the present invention, the residual solvent amount can be expressed by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is a mass at a predetermined time of the casting membrane (film), and N is a mass when M is dried at 115 ° C. for 1 hour. In particular, M when calculating the amount of residual solvent achieved in the solvent evaporation step is the mass of the cast film immediately before the peeling step.

[5-4] Peeling Step The cast film having the solvent evaporated on the metal support is peeled off at the peeling position.

  The peeling tension at the time of peeling the metal support and the cast film is usually in the range of 60 to 400 N / m. However, if wrinkles easily occur at the time of peeling, the peeling is carried out with a tension of 190 N / m or less. It is preferable.

  In the present invention, the temperature at the peeling position on the metal support is preferably in the range of −50 to 60 ° C., more preferably in the range of 10 to 40 ° C., and in the range of 15 to 40 ° C. Is most preferred.

  The peeled film may be sent directly to the stretching step, or may be sent to the stretching step after being sent to the first drying step so as to achieve a desired residual solvent amount. In the present invention, from the viewpoint of stable conveyance in the stretching step, it is preferable that the film is sequentially sent to the first drying step and the stretching step after the peeling step.

[5-5] First drying step The first drying step is a drying step in which the film is heated to further evaporate the solvent. The drying means is not particularly limited, and for example, hot air, infrared rays, a heating roller, microwaves and the like can be used. From the viewpoint of simplicity, it is preferable to dry with hot air or the like while transporting the film with rollers arranged in a staggered manner. The drying temperature is preferably in the range of 30 to 200 ° C. in consideration of the residual solvent amount and the stretching ratio in transportation.

[5-6] Stretching Step By stretching the transparent heat-resistant laminated film peeled off from the metal support, the thickness, flatness, orientation and the like of the film can be controlled.

  In the manufacturing method of the transparent heat resistant laminated film according to the present invention, it is preferable to stretch in the longitudinal direction and / or the width direction.

  The stretching operation may be performed in multiple stages. Moreover, when performing biaxial stretching, simultaneous biaxial stretching may be performed and you may implement in steps. In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible.

Thus, for example, the following stretching steps are possible:
-Stretch in the longitudinal direction-> Stretch in the width direction-> Stretch in the longitudinal direction-> Stretch in the longitudinal direction-Stretch in the width direction-> Stretch in the width direction-> Stretch in the longitudinal direction-> Stretch in the longitudinal direction Includes stretching in one direction and contracting the other while relaxing the tension.

  The amount of residual solvent at the start of stretching is preferably in the range of 2 to 50% by mass.

  If the amount of the residual solvent is 2% by mass or more, the film thickness deviation is small and preferable from the viewpoint of flatness, and if it is within 50% by mass, the surface unevenness is reduced and the flatness is improved.

  In the method for producing a transparent heat-resistant laminated film of the present invention, the film may be stretched in the longitudinal direction and / or the lateral direction, preferably in the lateral direction so that the thickness after stretching is in a desired range. The film is preferably stretched in a temperature range of (TgL−200) to (TgH + 50) ° C., where TgL is the lowest Tg and TgH is the highest Tg of the glass transition point (Tg) of the film. If it extends in the said temperature range, since a extending | stretching stress can be reduced, haze will become low. Moreover, generation | occurrence | production of a fracture | rupture is suppressed, and the transparent heat resistant laminated | multilayer film containing the polyimide which was excellent in planarity and the coloring property of the film itself are obtained. The stretching temperature is more preferably in the range of (TgL−150) to (TgH + 40) ° C.

  In the method for producing a transparent heat-resistant laminated film of the present invention, the film having self-supporting property peeled from the support can be stretched in the longitudinal direction by regulating the running speed with a stretching roller. The draw ratio in the longitudinal direction is preferably 1.03 to 2.00 times, more preferably 1.10 to 1.80 times, and even more preferably 1.20 to 1.60 times in a temperature range of 30 to 250 ° C. is there.

  In order to stretch the film in the width direction, for example, the entire width of the film is held with clips or pins in the width direction for the entire drying process or a part of the process as disclosed in JP-A-62-46625. A method of drying while drying (referred to as a tenter method), among which a tenter method using a clip is preferably used.

  The film stretched in the longitudinal direction or the unstretched film is preferably introduced into the tenter in a state where both ends in the width direction are gripped by the clip, and stretched in the width direction while running with the tenter clip. Although the draw ratio of the width direction is not specifically limited, 1.03-2.00 times are preferable in a temperature range of 30-300 degreeC, More preferably, it is 1.10-1.80 times, More preferably, it is 1.20. 1.60 times.

  From the viewpoint of improving the flatness of the film, it is preferable to stretch the film in the width direction at a stretching speed of 50 to 1000% / min.

  If the stretching speed is 50% / min or more, the planarity is improved and the film can be processed at high speed, which is preferable from the viewpoint of production aptitude, and if it is within 1000% / min, the film is broken. Can be processed without any problem.

  A more preferable stretching speed is in the range of 100 to 500% / min. The stretching speed is defined by the following formula.

Stretching speed (% / min) = [(d ₁ / d ₂ ) −1] × 100 (%) / t
(In the above formula, d ₁ is the width dimension in the stretching direction of the resin film after stretching, d ₂ is the width dimension in the stretching direction of the resin film before stretching, and t is the time (min) required for stretching. .)
In the stretching step, usually, after stretching, holding and relaxation are performed. That is, in this step, it is preferable to perform a stretching step for stretching the film, a holding step for holding the film in a stretched state, and a relaxation step for relaxing the film in the stretched direction in this order. In the holding step, the drawing at the draw ratio achieved in the drawing step is held at the drawing temperature in the drawing step. In the relaxation stage, the stretching in the stretching stage is held in the holding stage, and then the stretching is relaxed by releasing the tension for stretching. The relaxation step may be performed at a temperature lower than the stretching temperature in the stretching step.

[5-7] Second drying step Next, the stretched film is heated and dried. When the film is heated with hot air or the like, a means for preventing the mixing of used hot air by installing a nozzle that can exhaust used hot air (air containing solvent or wet air) is also preferably used. The hot air temperature is more preferably in the range of 40 to 350 ° C. The drying time is preferably about 5 seconds to 30 minutes, and more preferably 10 seconds to 15 minutes.

  Further, the heating and drying means is not limited to hot air, and for example, infrared rays, heating rollers, microwaves, and the like can be used. From the viewpoint of simplicity, it is preferable to dry with hot air or the like while transporting the film with rollers arranged in a staggered manner. The drying temperature is more preferably in the range of 40 to 350 ° C. in consideration of the residual solvent amount, the expansion / contraction rate in conveyance, and the like.

  In the second drying step, it is preferable to dry the film until the residual solvent amount is 0.5% by mass or less.

[5-8] Winding Step The winding step is a step of winding the obtained film and cooling it to room temperature. The winding machine may be a commonly used one, and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, a program tension control method with a constant internal stress, or the like.

  The thickness in particular of a film is not restrict | limited, For example, it is preferable to exist in the range of 5-200 micrometers, especially in the range of 7-50 micrometers.

  In the winding process, both ends of the film sandwiched between tenter clips when stretched and conveyed may be slit. The slit end is preferably reused as a return material. Here, the recycled material refers to a portion that is formed into a film and is reused as a raw material for some reason, and the slit end (also referred to as an ear), or the feeding / termination of production. In addition, a film that is not suitable as a product due to an appearance problem such as a scratch or a streak may be used. The slit film edge is finely cut to a width of 1 to 30 mm, and then dissolved in a solvent and reused.

  The ratio of the portion of the molded film that is reused as a recycled material is preferably in the range of 10 to 90% by mass, more preferably in the range of 20 to 80% by mass, and still more preferably in the range of 30 to 70% by mass. Is within.

  The input amount is slightly changed depending on the amount of return material generated in the middle of the film forming process or finally, but usually the mixing ratio of the returned material with respect to the total solid content in the dope is about 10 to 50% by mass, preferably, It is about 15-40 mass%. The mixing ratio of the recycled materials is preferably as constant as possible for production stability.

  Each step from the solvent evaporation step to the winding step described above may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas. Moreover, each process, especially a drying process and a extending process, are performed in consideration of the explosion limit concentration of the solvent in the atmosphere.

[5-9] Heating step After the winding step, the film dried in the second drying step is further heat-treated in order to improve imidization in the polymer chain molecules and between the polymer chain molecules to improve mechanical properties. A heating step can also be performed.

  Moreover, even when the dope is prepared using polyimide (imidation rate 100%) or when the imidation rate of the film becomes 100% by performing the second drying step, the residual stress of the film It is also preferable to carry out a heating step for the purpose of relaxing.

  In addition, the said 2nd drying process may serve as a heating process.

  A heating means is performed using well-known means, such as a hot air, an electric heater, and a microwave, for example. As the electric heater, the above-described infrared heater can be used.

The heat treatment conditions are such that the heater output and hot air temperature are adjusted so that the film L ^* value is 30 to 55, and the final treatment condition is in the temperature range of 200 to 450 ° C., and the range of 30 seconds to 1 hour. It is preferable to carry out as appropriate. Thereby, the dimensional stability of a polyimide film can be improved. In the heating step, if the film is heated rapidly, defects such as an increase in surface defects occur, and therefore it is preferable to select the heating method as appropriate. The heating step is preferably performed in a low oxygen atmosphere.

  When the heating temperature in the second drying step and the heating step exceeds 450 ° C., the energy required for heating becomes very large, resulting in an increase in manufacturing cost and an increase in environmental load. The following is preferable.

  In addition, after the winding process, before or after the heating process, a process of slitting the width direction end of the polyimide film, or a process of neutralizing the polyimide film if charged, etc. It is also good.

[5-10] Metal layer forming step When the transparent heat-resistant laminated film of the present invention is used, for example, for a transparent flexible printed circuit board described later, the metal layer is a base film in which an A layer and a B layer are laminated. It is formed by pressing a metal foil on the top via an adhesive.
Examples of the adhesive used here include acrylic, polyimide, and epoxy adhesives.
In addition, when the transparent heat-resistant laminated film of the present invention is used for a transparent electrode substrate described later, for example, in addition to ITO as a metal layer (transparent conductive layer), silver nanowire, metal mesh (silver, copper), etc. The metal layer is used. In the case of ITO, a physical vapor deposition method such as a sputtering method is preferable. In the case of silver nanowires, a transparent conductive layer forming composition containing metal nanowires is applied on a base film. Can be formed. In the case of a metal mesh, fine metal wires are formed in a lattice pattern on the base film. Details will be described later.

  In addition, as a method of said (2), the process of said [5-1]-[5-9] is each performed by A layer and B layer, A layer single layer film, and B layer single layer Each film is prepared, and the A layer and the B layer are adhered via an optical adhesive such as an optical clear adhesive (OCA) or a pressure sensitive adhesive (PSA). A base film composed of an A layer and a B layer is prepared by bonding with a thermosetting or photocurable adhesive. Then, a transparent heat-resistant laminated film can be produced on the B layer through the process [5-10].

[6] Transparent flexible printed circuit board, transparent electrode substrate]
[6-1] Transparent flexible printed circuit board The transparent flexible printed circuit board of the present invention is obtained by forming an electric circuit on the transparent heat-resistant laminated film of the present invention. An example of the transparent flexible printed circuit board is a flexible printed circuit board (FPC).

[6-2] Transparent electrode substrate The transparent heat-resistant laminated film of the present invention is also suitable as a transparent electrode substrate.
The transparent electrode substrate has at least a base film (hereinafter also referred to as a base material) composed of the A layer and the B layer of the present invention and a metal layer (hereinafter also referred to as a transparent conductive layer).
The transparent conductive layer is preferably a conductive layer having transparency and visibility and capable of patterning. For example, in addition to ITO (indium-tin composite oxide), metal nanowires such as silver nanowires, metal meshes such as metal mesh (silver, copper), and the like can be given.
Further, the base film preferably has high transparency (high transmittance, low haze).

  In addition, the resistance value of the transparent conductive layer of the present application is in the range of 0.01 to 150Ω / □. More preferably, the resistance value of the transparent conductive layer is in the range of 0.1 to 100Ω / □. When the resistance value of the transparent conductive layer is 0.01Ω / □ or more, durability against keystroke is obtained, and when the resistance value is 150Ω / □ or less, it is preferable from the viewpoint of curling.

(ITO)
When ITO (indium-tin composite oxide) is used as the transparent conductive layer, the content of tin oxide (SnO ₂ ) in the metal oxide is the total amount of tin oxide and indium oxide (In ₂ O ₃ ). On the other hand, it is preferably in the range of 0.5 to 15% by mass, preferably in the range of 3 to 15% by mass, more preferably in the range of 5 to 12% by mass, More preferably, it is not 12% by weight on the leaves. If the amount of tin oxide is too small, the durability of the ITO film may be inferior. Moreover, when there is too much quantity of a tin oxide, an ITO film | membrane will become difficult to crystallize and transparency and stability of resistance value may not be enough.

  ITO in this specification may be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of the additional component include metal elements other than In and Sn. Specifically, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, Fe , Pb, Ni, Nb, Cr, Ga, and combinations thereof. The content of the additional component is not particularly limited, but may be 3% by mass or less.

  The transparent conductive layer may have a structure in which a plurality of indium-tin composite oxide layers having different amounts of tin from each other are stacked. In this case, the ITO film may be two layers or three or more layers.

  The method of forming the transparent conductive layer when ITO is used as the transparent conductive layer is not particularly limited. From the viewpoint of the uniformity of the layer thickness and the film formation efficiency, chemical vapor deposition (CVD) or physical vapor deposition A vacuum film formation method such as (PVD) is preferably employed. Of these, physical vapor deposition methods such as vacuum vapor deposition, sputtering, ion plating, and electron beam vapor deposition are preferred, and sputtering is particularly preferred.

  From the viewpoint of obtaining a long laminate, the film formation of the transparent conductive layer is preferably performed while the film substrate is conveyed by, for example, a roll-to-roll method.

As the sputtering target, a target having the ITO composition can be suitably used. In sputter film formation, first, the degree of vacuum (degree of ultimate vacuum) in the sputtering apparatus is preferably evacuated to 1 × 10 ⁻³ Pa or less, more preferably 1 × 10 ⁻⁴ Pa or less. It is preferable to create an atmosphere from which impurities such as moisture and organic gas generated from the substrate are removed. This is because the presence of moisture or organic gas terminates dangling bonds generated during sputtering film formation and hinders the crystal growth of a conductive oxide such as ITO.

  Into the sputter apparatus evacuated in this manner, an inert gas such as Ar and oxygen gas as a reactive gas are introduced as necessary, and the substrate is transported under a reduced pressure of 1 Pa or less. Do the membrane. The pressure during film formation is preferably in the range of 0.05 to 1 Pa, and more preferably in the range of 0.1 to 0.7 Pa. If the film formation pressure is too high, the film formation rate tends to decrease. Conversely, if the pressure is too low, the discharge tends to become unstable.

  The substrate temperature when sputtering ITO is formed is preferably in the range of −10 to 190 ° C., and more preferably in the range of −10 ° C. to 150 ° C.

(Metal nanowires)
The metal nanowire is a conductive material whose material is metal, the shape is needle-like or thread-like, and the diameter is nanometer size. The metal nanowire may be linear or curved. If a transparent conductive layer composed of metal nanowires is used, the metal nanowires can be shaped like a mesh, so that a good electrical conduction path can be formed even with a small amount of metal nanowires. Can be obtained. Furthermore, when the metal nanowire has a mesh shape, a transparent conductive film having a high light transmittance can be obtained by forming openings in the mesh space.

  The ratio between the thickness d and the length L of the metal nanowire (aspect ratio: L / d) is preferably in the range of 10 to 100,000, more preferably in the range of 50 to 100,000. Particularly preferably in the range of 100 to 10,000. Thus, if metal nanowire with a large aspect ratio is used, metal nanowire cross | intersects favorably and high electroconductivity can be expressed with a small amount of metal nanowire. As a result, a transparent conductive film having a high light transmittance can be obtained.

In the present specification, the “thickness of the metal nanowire” means the diameter when the cross section of the metal nanowire is circular, and the short diameter when the cross section of the metal nanowire is elliptical. If it is square, it means the longest diagonal. The thickness and length of the metal nanowire can be confirmed by a scanning electron microscope or a transmission electron microscope.
The thickness of the metal nanowire is preferably less than 500 nm, more preferably less than 200 nm, particularly preferably in the range of 10 to 100 nm, and most preferably in the range of 10 to 50 nm. If it is such a range, a transparent conductive layer with high light transmittance can be formed.

The length of the metal nanowire is preferably in the range of 2.5 to 1000 μm, more preferably in the range of 10 to 500 μm, and particularly preferably in the range of 20 to 100 μm. If it is such a range, a highly conductive transparent electrode substrate can be obtained.
Any appropriate metal can be used as the metal constituting the metal nanowire as long as it is a highly conductive metal. As a metal which comprises the said metal nanowire, silver, gold | metal | money, copper, nickel etc. are mentioned, for example. Moreover, you may use the material which performed the plating process (for example, gold plating process) to these metals. Among these, silver or copper is preferable from the viewpoint of conductivity.

Arbitrary appropriate methods may be employ | adopted as a manufacturing method of the said metal nanowire. For example, a method of reducing silver nitrate in a solution, a method in which an applied voltage or current is applied to the precursor surface from the tip of the probe, a metal nanowire is pulled out at the probe tip, and the metal nanowire is continuously formed. Can be mentioned. In the method of reducing silver nitrate in a solution, silver nanowires can be synthesized by liquid phase reduction of a silver salt such as silver nitrate in the presence of a polyol such as ethylene glycol and polyvinylpyrrolidone.
Uniform sized silver nanowires are described in, for example, Xia, Y. et al. etal. , Chem. Mater. (2002), 14, 4736-4745, Xia, Y. et al. etal. , Nano letters (2003) 3 (7), 955-960, and mass production is possible.

The said transparent conductive layer can be formed by apply | coating the composition for transparent conductive layer formation containing the said metal nanowire on the said base film. More specifically, after the dispersion liquid (composition for forming a transparent conductive layer) in which the metal nanowires are dispersed in a solvent is applied on the base film, the coating layer is dried to form a transparent conductive layer. Can be formed.
Examples of the solvent include water, alcohol solvents, ketone solvents, ether solvents, hydrocarbon solvents, aromatic solvents and the like. From the viewpoint of reducing the environmental load, it is preferable to use water.
The dispersion concentration of the metal nanowires in the composition for forming a transparent conductive layer containing the metal nanowires is preferably in the range of 0.1 to 1% by mass. If it is such a range, the transparent conductive layer excellent in electroconductivity and light transmittance can be formed.

  The composition for transparent conductive layer formation containing the said metal nanowire may further contain arbitrary appropriate additives according to the objective. Examples of the additive include a corrosion inhibitor that prevents corrosion of metal nanowires, and a surfactant that prevents aggregation of metal nanowires. The kind, number, and amount of additives used can be appropriately set according to the purpose. Moreover, the said composition for transparent conductive layer formation may contain arbitrary appropriate binder resins as needed, as long as the effect of this invention is acquired.

Arbitrary appropriate methods may be employ | adopted as a coating method of the composition for transparent conductive layer formation containing the said metal nanowire. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, letterpress printing method, intaglio printing method, and gravure printing method.
Any appropriate drying method (for example, natural drying, air drying, heat drying) can be adopted as a method for drying the coating layer. For example, in the case of heat drying, the drying temperature is typically in the range of 100 to 200 ° C., and the drying time is typically in the range of 1 to 10 minutes.

When the transparent conductive layer contains metal nanowires, the thickness of the transparent conductive layer is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 3 μm, and particularly preferably. Is in the range of 0.1 to 1 μm. If it is such a range, the film excellent in electroconductivity and light transmittance can be obtained.
When the said transparent conductive layer contains metal nanowire, the total light transmittance of the said transparent conductive layer becomes like this. Preferably it is 85% or more, More preferably, it is 90% or more, More preferably, it is 95% or more.

(Metal mesh)
The transparent conductive layer containing a metal mesh is formed by forming fine metal wires in a lattice pattern on a base film (base material) composed of the A layer and the B layer according to the present invention. Any appropriate metal can be used as the metal constituting the metal mesh as long as it is a highly conductive metal. As a metal which comprises the said metal mesh, silver, gold | metal | money, copper, nickel etc. are mentioned, for example. Moreover, you may use the material which performed the plating process (for example, gold plating process) to these metals. Among these, copper is preferable, and a migration phenomenon is unlikely to occur, which is preferable from the viewpoint of suppressing disconnection during keystroke.

The transparent conductive layer containing a metal mesh can be formed by any appropriate method. For example, the transparent conductive layer is formed by applying a photosensitive composition containing silver salt (a composition for forming a transparent conductive layer) onto the laminate, and then performing an exposure process and a development process to form a fine metal wire in a predetermined pattern. It can obtain by forming. The transparent conductive layer can also be obtained by printing a paste containing metal fine particles (a composition for forming a transparent conductive layer) in a predetermined pattern.
Details of such a transparent conductive layer and a method for forming the transparent conductive layer are described in, for example, Japanese Patent Application Laid-Open No. 2012-18634, and the description thereof is incorporated herein by reference. Moreover, as another example of the transparent conductive layer comprised from a metal mesh, and its formation method, the transparent conductive layer and its formation method of Unexamined-Japanese-Patent No. 2003-331654 are mentioned.
When the said transparent conductive layer contains a metal mesh, the thickness of the said transparent conductive layer becomes like this. Preferably it exists in the range of 0.1-30 micrometers, More preferably, it exists in the range of 0.1-9 micrometers.
When the said transparent conductive layer contains a metal mesh, the transmittance | permeability of the said transparent conductive layer becomes like this. Preferably it is 80% or more, More preferably, it is 85% or more, More preferably, it is 90% or more.

  The transparent electrode substrate may include any appropriate other layer as necessary. Examples of the other layers include a hard coat layer, an antistatic layer, an antiglare layer, an antireflection layer, and a color filter layer.

[7] LED lighting device The lighting device of the present invention is not particularly limited as long as it is made of a transparent heat resistant laminated film produced by the method for producing a transparent heat resistant laminated film of the present invention. .

  Specifically, the LED illumination device covers a step of preparing a flexible printed board having a metal part using the transparent heat-resistant laminated film according to the present invention, a step of fixing an LED chip on the board, and a metal part. Thus, the coating composition for the barrier layer is applied to form the barrier layer, the composition for the wavelength conversion layer containing the transparent resin and the phosphor particles is applied so as to cover the LED chip, and the wavelength conversion layer is applied. It is formed by a forming process or the like.

[8] Organic electroluminescence display device In the organic electroluminescence display device of the present invention, a transparent heat resistant laminated film produced by the method for producing a transparent heat resistant laminated film of the present invention, and a flexible display substrate comprising the transparent heat resistant laminated film are provided. It is preferable to have.

  As for the outline of the organic EL element applicable to the organic electroluminescence display device of the present invention, for example, JP 2013-157634 A, JP 2013-168552 A, JP 2013-177361 A, JP 2013-2013 A. No. 187111, JP 2013-191644, JP 2013-191804, JP 2013-225678, JP 2013-235994, JP 2013-243234, JP 2013-243236 JP, 2013-242366, JP 2013-243371, JP 2013-245179, JP 2014-003249, JP 2014-003299, JP 2014-013910, Japanese Patent Application Laid-Open No. 2014-017493 Distribution, may be mentioned arrangement described in JP 2014-017494 Patent Publication.

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

The structures of the compounds used in the following examples are listed below.

In addition, the acquisition place of the commercial item of said compound is as follows.
Acid anhydride 1: Daikin Industries, Ltd. Diamine 1: Daikin Industries, Ltd.

(Preparation of polyimide film [1])
To a 4-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a Dean-Stark aggregator filled with toluene, and a stirrer, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1, 25,59 g (57.6 mmol) of 3,3,3-hexafluoropropane dianhydride (acid anhydride 1) (manufactured by Daikin Industries, Ltd.) was added to N, N-dimethylacetamide (134 g) at room temperature under a nitrogen stream. Stir with.

  To this, 19.2 g (60 mmol) of 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl (diamine 1) (manufactured by Daikin Industries, Ltd.) was added, and the mixture was stirred with heating at 80 ° C. for 6 hours. Thereafter, the external temperature was heated to 190 ° C., and water generated along with imidization was distilled off azeotropically with toluene. When heating, refluxing, and stirring were continued for 6 hours, generation of water was not observed. Subsequently, the mixture was heated for 7 hours while distilling off toluene. Further, after distilling off toluene, methanol was added for reprecipitation, and after drying the solid content, an 8% by mass dichloromethane solution was prepared to obtain polyimide solution A containing polyimide resin A. Prepared. The weight average molecular weight of the polyimide resin A was 140,000.

(Preparation of dope)
A main dope having the following composition was prepared. First, dichloromethane (boiling point 40 ° C.) was added to the pressure dissolution tank. The prepared polyimide solution A was charged into a pressure dissolution tank containing a solvent while stirring. While this was heated and stirred, it was completely dissolved, and this was dissolved in Azumi Filter Paper No. The main dope was prepared by filtration using 244.

(Main dope composition)
Dichloromethane 350 parts by weight Polyimide solution A 100 parts by weight Matting agent (Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) 0.5 parts by weight

(Casting process)
Next, using an endless belt casting apparatus, the dope was cast uniformly on a stainless steel belt support at a temperature of 30 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

(Peeling process)
On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast film (web) cast was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 180 N / m. did.

(Preliminary drying process)
While the peeled cast film was conveyed by a roller, it was pre-dried so that the residual solvent amount was 15% by mass immediately before entering the tenter.

(Stretching process)
The pre-dried cast film was stretched 1.50 times in the width direction using a clip-type tenter while maintaining the temperature from the start of stretching to the end of stretching at 250 ° C. The residual solvent amount at the start of stretching was 15% by mass.

(Drying process)
While the stretched film is being transported by a large number of rollers, the transport tension is 100 N / m, the drying time is 15 minutes, and the residual solvent amount is less than 500 ppm by mass, and the polyimide film [1] is dried at a drying temperature of 120 ° C. Obtained.

(Preparation of polyimide film [2])
As the polyimide film [2], Neoprim L L-3430 manufactured by Mitsubishi Gas Chemical Co., Ltd. was used.

(Preparation of polyimide film [3])
As a reactor, 769 g of N, N-dimethylacetamide (DMAc) was charged while passing nitrogen through a 1.5 L reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser, and the reaction was performed. After adjusting the temperature of the vessel to 25 ° C., 64.046 g (0.2 mol) of 2,2′-bis (trifluoromethyl) benzidine (TFDB) was dissolved to obtain a first solution. Maintained at ° C. To the first solution, 8.885 g (0.02 mol) of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanoic dianhydride (6FDA) and 3,3,4 ', 4'-biphenyltetracarboxylic After charging 17.653 g (0.06 mol) of acid dianhydride (BPDA) (BPDA), the mixture was stirred for a certain time to be dissolved and reacted to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, 24.362 g (0.12 mol) of terephthalic acid chloride (TPC) was added to obtain a polyamic acid solution having a solid content of 13 chambers%.

  After 13 g of pyridine and 17 g of acetic anhydride were added to the polyamic acid solution and stirred at 25 ° C. for 30 minutes, the mixture was further stirred at 70 ° C. for 1 hour and cooled to room temperature, and this was precipitated in 20 L of methanol. After filtration and pulverization, the resultant was dried at 100 ° C. in vacuum for 6 hours to obtain 108 g of a solid polyamide powder copolymer polyamide-imide.

The 108 g of solid powder copolymer polyamide-imide was dissolved in 722 g of N, N-dimethylacetamide (DMAc) to obtain a 13% by mass solution.
The solution thus obtained was applied to a stainless steel plate, cast to a thickness of 390 μm, dried with hot air at 130 ° C. for 30 minutes, and then peeled off from the stainless steel plate and fixed to the frame with a pin. The frame on which the film was fixed was placed in a vacuum oven, slowly heated from 100 ° C. to 300 ° C. for 2 hours, then gradually cooled and separated from the frame to obtain a polyamide-imide film. Thereafter, as a final heat treatment step, the polyamide-imide film was further heat treated at 300 ° C. for 30 minutes to obtain a polyimide film [3].

(Preparation of polyimide film [4]) In a 500 mL five-necked flask equipped with a thermometer, a stirrer, a nitrogen introducing tube, a dropping funnel with a side tube, a Dean-Stark device and a cooling tube, 4,4 ′ as a diamine under a nitrogen stream -Bis (4-aminophenoxy) biphenyl 18.515 g (0.050 mol), 3,3′-dihydroxybenzidine 2.719 g (0.013 mol) as phenolic hydroxyl group-containing diamine, and γ-butyrolactone 42 as organic solvent .31 g and N, N-dimethylacetamide 10.58 g were charged and dissolved. Thereto, 1,2,4,5-cyclohexanetetracarboxylic dianhydride (14.072 g, 0.063 mol) and 0.3 g (0.005 mol) of triethylamine as an imidation catalyst were added all at once. After completion of the dropwise addition, the temperature was raised to 180 ° C. and refluxed for 1 hour while distilling off the distillate as needed. After confirming that the distillation of water was completed, the solution was cooled to 60 ° C. to obtain a polyimide resin solution. It was. The number average molecular weight of the polyimide resin was 385,000.
After cooling to 60 ° C., 385 g of “DMAC-ST” (average particle diameter of 11 nm, silica content of 20 mass%, N, N-dimethylacetamide solution: manufactured by Nissan Chemical Industries, Ltd.) was added as silica fine particles and stirred for 2 hours. A polyimide resin composition was obtained by mixing.
The obtained polyimide resin composition was applied on a glass plate, held on a hot plate at 100 ° C. for 60 minutes, and an organic solvent was volatilized to obtain a colorless and transparent primary dry film having self-supporting property. This film was fixed to a stainless steel frame and heated in a hot air dryer at 250 ° C. for 2 hours to evaporate the organic solvent to obtain a polyimide film [4].

(Preparation of polyimide film [5])
Using SPIXAREA TP001 (Somar) as a polyimide solution, this polyimide solution, a dispersion in which silica particles with a solid content concentration of 30% by mass are dispersed in γ-butyrolactone, and a dimethylacetamide solution of alkoxysilane having an amino group are mixed. And stirred for 30 minutes.
Here, the mass ratio of silica particles to polyimide was 60:40, and the amount of alkoxysilane having an amino group was 1.67 parts by mass with respect to 100 parts by mass in total of silica particles and polyimide.
The mixed solution was applied to a glass substrate and heated at 50 ° C. for 30 minutes and 140 ° C. for 10 minutes to dry the solvent. Then, the film was peeled from the glass substrate, a metal frame was attached, and the polyimide film [5] was obtained by heating at 210 ° C. for 1 hour.

  The thermal expansion coefficients (CTE) of the polyimide films [1] to [5] obtained above were measured by the method described later and are shown in Table I below. Table I shows the thickness and imide group concentration when the thermal expansion coefficient of each polyimide film was measured. The polyimide film [1] is a fluorine-based polyimide.

[Example 1]
(Preparation of transparent heat-resistant laminated film [101])
A polyimide film [1] having a thickness of 35 μm is used as the A layer, a polyimide film [3] having a thickness of 5 μm is used as the B layer, and the polyimide film [1] and the polyimide film [3] have a thickness of 5 μm. In this way, an acrylic adhesive was applied and cured to form a metal layer made of ITO on the polyimide film [3] according to the following method to produce a transparent heat resistant laminated film [101].
As a specific method for forming a metal layer made of ITO, a base film made of polyimide film [1] (A layer) and polyimide film [3] (B layer) is composed of 97% by mass of indium oxide and 3% of tin oxide. The indium tin oxide layer having a thickness of 27 nm was formed on the polyimide film [3] by a sputtering method in a sputtering apparatus having a fired body target containing mass%.
Next, the base film provided with the indium tin oxide layer was heat-treated at 150 ° C. for 90 minutes to convert the indium tin oxide layer from amorphous to crystalline.

(Preparation of transparent heat resistant laminated film [102] to [106])
In the production of the transparent heat-resistant laminated film [101], the types of polyimide films used for the A layer and the B layer and the layer thicknesses of the A layer and the B layer were changed in accordance with the following Table II. Laminated films [102] to [106] were produced.

[Example 2]
(Preparation of transparent heat resistant laminated film [201] to [204])
In preparation of the transparent heat-resistant laminated film [101], except that the type of polyimide film used for the A layer and the B layer and the layer thickness of the polyimide film used for the A layer and the B layer were changed according to Table III below. Thus, transparent heat-resistant laminated films [201] to [204] were produced. The ratio of the layer thicknesses of the A layer and the B layer is shown in Table III below.

[Example 3]
(Preparation of transparent heat resistant laminated film [301] to [305])
In the production of the transparent heat-resistant laminated film [101], the type of the polyimide film used for the B layer and the layer thickness of the polyimide film used for the A layer and the B layer are changed according to Table IV below and used for the A layer. Each of the transparent heat resistant laminated films [301] to [301] was prepared in the same manner except that the polyimide film [1] was prepared so that the residual solvent amount (drying step) of the polyimide film [1] was the solvent amount described in Table IV below. [305] was produced. The ratio of the layer thicknesses of the A layer and the B layer is shown in Table IV below.

[Example 4]
(Production of transparent electrode substrates [401], [402], [405] and [406])
In preparation of the said transparent heat resistant laminated film [101], it is the same except having changed the kind of the polyimide film used for A layer and B layer, and the layer thickness of the polyimide film used for A layer and B layer according to the following table V Thus, transparent electrode substrates [401], [402], [405] and [406] were produced.

(Preparation of transparent electrode substrate [403])
A transparent electrode substrate [403] was produced in the same manner as in the production of the transparent electrode substrate [402] except that the metal layer formed on the B layer was changed from ITO to a copper mesh.
As a method for forming a metal layer made of copper mesh, a base film made of polyimide film [1] (A layer) and polyimide film [4] (B layer) was pre-treated by glow discharge. The base film after this pretreatment was placed in a vacuum chamber of a magnetron type sputtering apparatus so as to face a copper target, and the degree of vacuum obtained by completely substituting air with argon was 2.7 × 10 ⁻¹ Pa (2 × In an environment of 10 ⁻³ Torr), sputter deposition was repeated three times at an applied voltage of DC 9 kW at 1 m / min, and the thickness of the copper thin film obtained above was 0.6 μm. Next, referring to paragraphs 0046 to 0050 of JP-A-11-243296, a copper mesh conductive layer was formed to obtain a transparent electrode substrate [403].

(Preparation of transparent electrode substrate [404])
A transparent electrode substrate [404] was prepared in the same manner as in the production of the transparent electrode substrate [402] except that the metal layer formed on the B layer was changed from ITO to silver nanowires.
Silver nanowires are Sun, B.M. Gates, B.B. Mayers, & Y. Xia, “Crystalline silver nanos by soft solution processing”, Nano letters, (2002), 2 (2) 165-168, followed by a process using polyols in the presence of polyvinyl pyrrolidone (PVP). It is a nanowire synthesized by dissolving silver sulfate and reducing it. That is, in the present invention, nanowires synthesized by the modified polyol method described in Cambrios Technologies Corporation US Provisional Application No. 60 / 815,627 were used.
Silver nanowire water containing 0.5% w / v of a silver nanowire having a minor axis diameter of about 70 to 80 nm and an aspect ratio of 100 or more synthesized by the above method as a silver nanowire forming a metal layer A dispersion composition (ClearOmTM, Ink-A AQ, manufactured by Cambrios Technologies Corporation) is used as a base comprising a polyimide film [1] (A layer) and a polyimide film [4] (B layer) using a slot die coating machine. On the polyimide film [4], after coating and drying to a thickness of 1.5 μm after drying, a pressure treatment is performed at a pressure of 2000 kN / m ² to form a metal layer, and a transparent electrode substrate [ 404].

[Evaluation]
The following items were calculated or evaluated, and the results are shown in Tables I to V.
(Coefficient of thermal expansion)
A test piece of polyimide film having a thickness of 35 μm consisting of a single A layer is 20 mm long and 3 mm wide, and a tensile rate of 50 mN is applied to the test piece at a heating rate of 10 ° C./min from 23 ° C. When the temperature is raised to Tg-50 ° C of the film, the temperature is then lowered to 23 ° C, and the temperature is raised again from 23 ° C to Tg-50 ° C of the film at a rate of temperature rise of 10 ° C / min. The thermal expansion coefficient at 50 to 200 ° C. was calculated according to the following formula.
<Expression> Thermal expansion coefficient (ppm / ° C.) = ((Sample length at 200 ° C.) − (Sample length at 50 ° C.) / (Sample length at 23 ° C.)) / (200 ° C.-50 ° C. ) × 10 ⁶
In addition, it measured similarly to the above about the polyimide film which consists of B layer single layer.

(Layer thickness)
Regarding the layer thicknesses of the A layer and the B layer, the thickness of each single layer was measured with a contact type film thickness meter.

(Residual solvent amount of dichloromethane contained in layer A)
The amount of dichloromethane residual solvent contained in the A layer was calculated based on the following formula (Z).
Formula (Z)
Residual solvent amount (%) = (mass before heat treatment of cast film or film (A layer) −mass after heat treatment of cast film or film (A layer)) / (cast film or film (A layer)) Mass after heat treatment) x 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

(Transparency: Yellow index value)
The yellow index value was determined according to YI (yellow index: yellowness index) of the film defined in JIS K 7103.
As a measuring method of the yellow index value, a sample of a base film composed of A layer and B layer is prepared, and JIS is used by using a spectrophotometer U-3300 of Hitachi High-Technologies Corporation and the attached saturation calculation program. The tristimulus values X, Y and Z of the light source color defined in Z 8701 were obtained, and the yellow index value was obtained according to the definition of the following formula.
Yellow index value (YI value) = 100 (1.28X-1.06Z) / Y

(Durable adhesion)
Each transparent heat-resistant laminated film (or transparent electrode substrate) prepared above is bent to 5 mmφ, and when the following time has passed at 60 ° C. and 90% RH, it consists of a metal layer, an A layer, and a B layer. It was confirmed visually whether the interface with the base film was peeled off. Evaluation was carried out as follows by the time of peeling. ◎, ○, and △ are considered to be practically acceptable.
A: No peeling after 600 hours.
○: Peeled after 480 hours.
(Triangle | delta): It peeled after 360-hour progress.
X: Peeled after 240 hours or before 240 hours.

  From the results shown in Tables I to V, the transparent heat-resistant laminated film or the transparent electrode substrate of the present invention has better transparency than the transparent heat-resistant laminated film of the comparative example, and durability against wet heat with the metal layer. It can be seen that the adhesion is good.

[Example 5]
A polyimide film [1] having a thickness of 35 μm is used as the A layer, a polyimide film [3] having a thickness of 5 μm is used as the B layer, and the polyimide film [1] and the polyimide film [3] have a thickness of 5 μm. By applying and curing an acrylic adhesive as described above, the average thickness is measured by a direct current sputtering method using a sputtering facility comprising an unwinder, a sputtering device, and a winder on a polyimide film [3]. A 230 mass% 20 mass% Cr chromium-nickel alloy layer was formed as a metal thin film. Further, similarly, a copper thin film having an average thickness of 1000 mm was formed on the metal thin film.
Next, a 9 μm thick copper layer was provided on the copper thin film by electrolytic copper plating to obtain a metallized polyimide film. The copper plating bath used was a copper sulfate plating bath with a copper concentration of 23 g / L, and the bath temperature during plating was 27 ° C. In addition, the plating tank is a multi-structure tank in which a plurality of plating tanks are connected so that a polyimide film provided with a metal layer on one side is continuously immersed in each tank by an unwinder and a winder. Electroplating was performed while being conveyed. The conveyance speed was 75 m / h, and the average cathode current density of the plating tank was adjusted to 1.0 to 2.5 A / dm ² to perform copper plating.
Next, using this metal-coated polyimide film, a COF (Chip on film) having a wiring interval of 30 μm and a total wiring width of 15000 μm was produced by a subtractive method. An IC chip was mounted on this, and the electrodes on the surface of the IC chip and the lead portions of the wiring were subjected to wire bonding at 400 ° C. for 0.5 seconds using a wire bonding apparatus. At this time, the proportion of the bonding failure between the lead and the polyimide film generated in the inner lead portion was 0.0001%. A transparent flexible printed circuit board [1] was produced as described above.
About the produced transparent flexible printed circuit board [1], when said durable adhesive evaluation was performed, the interfacial peeling did not occur between the polyimide film and the metal thin film.

  From the evaluation results shown above, it is confirmed that the transparent heat-resistant laminated film of the present invention can be suitably used for a transparent flexible printed circuit board, a transparent electrode substrate, an LED lighting device including them, and an organic electroluminescence display device. It was done.

DESCRIPTION OF SYMBOLS 10 Co-casting die 11 Base part 13 Slit 14 Slit 16 Metal support 17 Dope for A layer 18 Dope for B layer 20 Multilayer structure web 21 A layer 22 B layer

Claims (8)

A transparent heat-resistant laminated film having A layer and B layer containing a transparent heat-resistant resin and a metal layer in this order,
The layer B has a smaller coefficient of thermal expansion than the layer A, and the layer thickness is thin.
The thermal expansion coefficient of the B layer is in the range of 10 to 40 ppm / ° C, and
A transparent heat-resistant laminated film, wherein a yellow index value including the A layer and the B layer is 3.0 or less.   The ratio of the thickness of the said A layer and B layer exists in the range of A layer: B layer = 99: 1-67: 33, The transparent heat-resistant laminated film of Claim 1 characterized by the above-mentioned. The layer A contains dichloromethane;
The transparent heat-resistant laminated film according to claim 1 or 2, wherein the dichloromethane content is in the range of 1 to 800 ppm by mass. The A layer contains a fluorine-based polyimide resin,
The B layer contains a polyimide resin, and the polyimide resin has an imide group concentration after imidization of the polyimide precursor in the range of 20 to 30% by mass. The transparent heat-resistant laminated film according to any one of claims 3 to 4.   A transparent flexible printed board comprising the transparent heat-resistant laminated film according to any one of claims 1 to 4.   A transparent electrode substrate comprising the transparent heat-resistant laminated film according to any one of claims 1 to 4.   An illumination device comprising the transparent heat-resistant laminated film according to any one of claims 1 to 4.   An organic electroluminescence display device comprising the transparent heat-resistant laminated film according to any one of claims 1 to 4.

Images