WO2018225825A1 - Method for producing substrate for flexible device - Google Patents

Abstract

The purpose of the present invention is to provide a method for forming a resin thin film laminate that makes it possible to preserve the exceptional performance attributes of exceptional heat resistance, low retardation, exceptional flexibility, and exceptional transparency, said resin thin film laminate being applied to a plastic thin film having exceptional performance as a base film of a flexible device substrate such as a flexible display substrate that can be easily peeled from a glass carrier. A method for producing a resin thin film laminate, said resin thin film laminate being characterized in that after a peeling layer is formed on a support substrate using a peeling-layer-forming composition containing a heat resistant polymer and an organic solvent, a resin thin film is formed on the peeling layer using a resin thin film-forming composition containing a heat resistant polymer and an organic solvent, and the peeling layer and the resin thin film are subsequently peeled from the support substrate as a single entity, said method being further characterized in that silicon dioxide particles having an average particle diameter of 100 nm or less as calculated from the specific surface area measured by nitrogen adsorption are incorporated in substantially only the resin thin film-forming composition.

Description

Manufacturing method of substrate for flexible device

The present invention relates to a method for producing a resin thin film laminate used as a base film for flexible printed circuit boards, particularly flexible printed boards such as flexible displays, and more specifically, heat resistance obtained by laminating a transparent laminate on a support substrate. The present invention relates to a polymer laminate.

In recent years, with rapid advances in electronics such as liquid crystal displays and organic electroluminescence displays, it has become necessary to make devices thinner and lighter, and more flexible.
In these devices, various electronic elements such as thin film transistors and transparent electrodes are formed on a glass substrate. By replacing this glass material with a flexible and lightweight resin material, the device itself can be made thinner or thinner. It is expected to be lightweight and flexible.
As a candidate for such a resin material, polyimide has attracted attention, and various reports on polyimide films have been made.

For example, Patent Document 1 relates to a polyimide useful as a plastic substrate for a flexible display and an invention related to a precursor thereof, and tetracarboxylic acids and various diamines containing an alicyclic structure such as cyclohexylphenyltetracarboxylic acid. It has been reported that the polyimide reacted with is excellent in transparency and heat resistance.

In addition, Patent Document 2 improves the compatibility of linear expansion coefficient, transparency, and low birefringence, which has been a drawback of conventional plastic substrates, by adding silica sol to polyimide. The application to can be expected.

On the other hand, when the advantages of the plastic substrate are pursued, the problem is the handleability and dimensional stability of the plastic substrate itself. In other words, if the plastic substrate is made into a thin film, it will prevent the occurrence of wrinkles and cracks, and after forming the functional layer and the positional accuracy when functional layers such as thin film transistors (TFT) and electrodes are formed. It becomes difficult to maintain the dimensional accuracy. Therefore, in Non-Patent Document 1, after a predetermined functional layer is formed on a plastic substrate that is applied and fixed on glass, a laser is irradiated from the glass side to force the plastic substrate provided with the functional layer from the glass. A separation method (a so-called laser lift-off process (a method called EPLaR method (Electronics-on-Plastic-by-Laser-Release)) has been proposed.

JP 2008-231327 A International Publication No. 2015/152178

The technique described in Non-Patent Document 1 described above guarantees the handleability and dimensional stability of a resin substrate by forming a functional layer on a plastic substrate fixed to glass using glass as a supporting base material. It is. However, this EPLaR method (laser lift-off method) is a technique in which the interface between the resin substrate and the support base material is destroyed by laser irradiation when separating the resin substrate from the support base material. There is a possibility that the characteristics of the resin substrate and the functional layer formed thereon may be deteriorated, such as a problem that the functional layer (TFT or the like) is damaged or a problem that the resin substrate itself is greatly damaged and the transmittance is lowered.

The present invention has been made in view of such circumstances, and is a resin thin film that provides a plastic thin film having excellent performance as a base film of a flexible device substrate such as a flexible display substrate that does not depend on the laser lift-off technology described above. Providing a manufacturing method for laminates, especially while maintaining excellent performance of excellent heat resistance, low retardation, excellent flexibility, and excellent transparency, as well as its handleability and dimensional stability It aims at providing the manufacturing method of the resin thin film laminated body (substrate for flexible devices) which can ensure.

As a result of intensive studies to achieve the above object, the present inventors have found that when forming a resin thin film in which silicon dioxide is blended with a heat resistant polymer in order to achieve both heat resistance and optical properties, By providing a release layer in between, the resin thin film laminate can be easily peeled off from the support substrate while maintaining the characteristics of excellent heat resistance, low retardation, excellent flexibility, and excellent transparency. The present invention has been completed.

That is, the present invention provides, as a first aspect, a method for producing a resin thin film laminate,
Forming a release layer on the support substrate using the release layer-forming composition containing the heat-resistant polymer A and an organic solvent;
A step of forming a resin thin film on the release layer using a composition for forming a resin thin film containing the heat-resistant polymer B and an organic solvent;
Peeling the support layer together with the release layer and the resin thin film to obtain a resin thin film laminate,
The resin thin film forming composition further includes silicon dioxide particles having an average particle diameter calculated from a specific surface area value measured by a nitrogen adsorption method of 100 nm or less, provided that
The release layer-forming composition does not contain silicon dioxide particles, and relates to a production method.
As a 2nd viewpoint, the said heat resistant polymer A and the said heat resistant polymer B are related with the manufacturing method as described in a 1st viewpoint which is the same polymer.
As a third aspect, the heat-resistant polymer A and the heat-resistant polymer B are each independently at least one polymer selected from polyimide, polybenzoxazole, polybenzobisoxazole, polybenzimidazole, and polybenzothiazole. The manufacturing method according to the first aspect.
As a fourth aspect, the heat-resistant polymer A and the heat-resistant polymer B are each independently a diamine containing a tetracarboxylic dianhydride component containing an alicyclic tetracarboxylic dianhydride and a fluorine-containing aromatic diamine. It is related with the manufacturing method as described in a 1st viewpoint which is a polyimide obtained by imidating the polyamic acid obtained by making a component react.
As a 5th viewpoint, the said alicyclic tetracarboxylic dianhydride is related with the manufacturing method as described in a 4th viewpoint containing the tetracarboxylic dianhydride represented by Formula (C1).

[Wherein B ¹ represents a tetravalent group selected from the group consisting of formulas (X-1) to (X-12).

(In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.)
As a 6th viewpoint, the said fluorine-containing aromatic diamine is related with the manufacturing method as described in a 4th viewpoint containing the diamine represented by a formula (A1).

(Wherein B ² represents a divalent group selected from the group consisting of formulas (Y-1) to (Y-34)).

(In the formula, * represents a bond.)
As a 7th viewpoint, the said polyimide is related with the manufacturing method as described in a 4th viewpoint containing the monomer unit represented by Formula (1), the monomer unit represented by Formula (2), or the monomer unit of both.

As an eighth aspect, the composition for forming a resin thin film includes the heat-resistant polymer B and the silicon dioxide particles in a mass ratio of 7: 3 to 3: 7. Regarding the method.
As a 9th viewpoint, the said silicon dioxide particle is related with the manufacturing method as described in a 1st viewpoint which has an average particle diameter of 60 nm or less.
As a tenth aspect, the present invention relates to the manufacturing method according to the first aspect, wherein either the release layer forming composition or the resin thin film forming composition further includes a crosslinking agent.
As an eleventh aspect, the present invention relates to the manufacturing method according to the first aspect, characterized in that the curing is by heat or ultraviolet rays.
As a twelfth aspect, the adhesiveness between the release layer and the resin thin film is peelable from 0 to 5% in the CCJ series (JIS5400) classification, and the adhesiveness between the support substrate and the release layer. It is related with the manufacturing method as described in the 1st viewpoint characterized by being able to peel 50% by CCJ series (JIS5400) classification.
As a thirteenth aspect, the present invention relates to the manufacturing method according to the first aspect, wherein the release layer has a thickness of 100 μm to 1 nm.
As a fourteenth aspect, the present invention relates to the manufacturing method according to the first aspect, wherein the step of obtaining the resin thin film laminate is performed using a method selected from cutting with a knife, mechanical separation, and peeling.
As a 15th viewpoint, it is related with the flexible substrate manufactured by the manufacturing method as described in any one among 1st viewpoint thru | or 14th viewpoint.

According to the method for producing a resin thin film laminate according to one aspect of the present invention, since the resin thin film laminate can be easily peeled from the support base, a low coefficient of linear expansion, excellent heat resistance, low retardation, and excellent flexibility The resin thin film laminate can be easily produced with good reproducibility without impairing performance such as performance.
The obtained resin thin film laminate exhibits a low linear expansion coefficient, high transparency (high light transmittance, low yellowness), low retardation, and excellent flexibility, so that it is a flexible device, particularly a flexible display. It can be suitably used as a substrate.
Such a method for producing a resin thin film laminate according to the present invention is a flexile device that requires characteristics such as high flexibility, low linear expansion coefficient, high transparency (high light transmittance, low yellowness), low retardation, and the like. The present invention can sufficiently cope with the progress in the field of industrial substrates, particularly flexible display substrates.

It is the figure which showed each step of the manufacturing method of this invention. It is a schematic diagram (sectional drawing) of the laminated body obtained by the manufacturing method of this invention. G1 represents a supporting substrate, L II represents a release layer, L I represents a resin thin film, and L IV represents an electrode layer formed on the resin thin film. It is a schematic diagram of the method of peeling the laminated body obtained by the manufacturing method of this invention from a support base material. It is a figure showing the structure of a peeling layer, a resin thin film, and an intermediate | middle layer in the laminated body obtained by the manufacturing method of this invention. 2 is a cross-sectional photograph (cross section TEM) of a laminate obtained in Example A. FIG. It is a figure which shows the cross-sectional photograph (cross section TEM) (a) of the laminated body obtained in Example A, and the component composition (b) of each layer. 2 is a Raman IR spectrum of a release layer, a resin thin film, and an interface thereof in the laminate obtained in Example A. FIG. 2 is a cross-sectional photograph (cross section TEM) of a laminate obtained in Example B. FIG. It is a figure which shows the cross-sectional photograph (cross section TEM) (a) of the laminated body obtained in Example B, and the component composition (b) of each layer. It is a Raman IR spectrum of the release layer, the resin thin film, and the interface thereof in the laminate obtained in Example B.

Hereinafter, the present invention will be described in detail.
In the method for producing a resin thin film laminate of the present invention, a release layer is formed using a composition for forming a release layer containing a heat resistant polymer A and an organic solvent on a supporting substrate, and then the heat resistant polymer B and the organic solvent are formed. A resin thin film is formed on the release layer using the composition for forming a resin thin film containing the resin, and the release layer and the resin thin film are peeled together (as an integral body) from the support substrate, and the resin thin film is laminated. When obtaining a body, characterized in that silicon dioxide particles having an average particle diameter of 100 nm or less calculated from the specific surface area value measured by the nitrogen adsorption method is substantially further contained only in the resin thin film forming composition. It is a method to do. In order to achieve the effect of the present invention, it is important that the silicon dioxide particles are substantially contained only in the resin thin film forming composition and not contained in the release layer forming composition. .
In the present invention, the term “substantially does not contain” silicon dioxide particles means that the composition does not contain silicon dioxide particles except for random mixing in the preparation process of the composition. It means that the content with respect to the heat-resistant polymer B in the composition for forming a release layer is smaller than the content of silicon dioxide particles with respect to the heat-resistant polymer A in the composition for forming a resin thin film. The content of silicon dioxide particles when silicon dioxide particles are mixed into the release layer forming composition is specifically 5% of the content of silicon dioxide particles with respect to the heat-resistant polymer A of the resin thin film forming composition. It is preferable that it is less than.
Hereinafter, first, each component which comprises these about the composition for peeling layer formation used for the manufacturing method of a resin thin film laminated body and the composition for resin thin film formation is demonstrated.

[Heat resistant polymer (A and B)]
The composition for forming a release layer and the composition for forming a resin thin film used in the present invention include a heat resistant polymer A and a heat resistant polymer B, respectively.
In the present invention, it is preferable that the heat-resistant polymer A contained in the release layer-forming composition and the heat-resistant polymer B contained in the resin thin-film-forming composition are the same (hereinafter referred to as heat-resistant polymer A and heat-resistant polymer A). The functional polymer B is collectively referred to as a heat resistant polymer).
As the heat-resistant polymer used in the present invention, at least one selected from polyimide, polybenzoxazole, polybenzobisoxazole, polybenzimidazole and polybenzothiazole is preferably used. Among them, polyimide is preferable, and in particular, a specific polyimide described later, that is, a polyamic obtained by reacting a tetracarboxylic dianhydride component including an alicyclic tetracarboxylic dianhydride and a diamine component including a fluorine-containing aromatic diamine. A polyimide obtained by imidizing an acid is preferred.
In the present specification, the heat-resistant polymer is a polymer having a weight loss of 5% or less at a temperature of 350 ° C. or higher.

[Polyimide]
The polyimide suitably used in the present invention imidizes polyamic acid obtained by reacting a tetracarboxylic dianhydride component containing an alicyclic tetracarboxylic dianhydride and a diamine component containing a fluorinated aromatic diamine. Is a polyimide obtained.
Among them, the alicyclic tetracarboxylic dianhydride includes a tetracarboxylic dianhydride represented by the following formula (C1), and the fluorine-containing aromatic diamine is represented by the following formula (A1). It is preferable that the diamine contains.

[Wherein B ¹ represents a tetravalent group selected from the group consisting of formulas (X-1) to (X-12).

(In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.)

(Wherein B ² represents a divalent group selected from the group consisting of formulas (Y-1) to (Y-34)).

(In the formula, * represents a bond.)

Among the tetracarboxylic dianhydrides represented by the above formula (C1), B ¹ in the formula is represented by the formulas (X-1), (X-4), (X-6), (X-7). It is preferable that it is a compound.
Of the diamines represented by the above (A1), B ² in the formula is preferably a compound represented by the formula (Y-12) or (Y-13).
As a preferred example, a polyimide obtained by imidizing a polyamic acid obtained by reacting a tetracarboxylic dianhydride represented by the above formula (C1) and a diamine represented by the above formula (A1) is described below. The monomer unit represented by Formula (2) is included.

In order to obtain a resin thin film laminate having low linear expansion coefficient, low retardation and high transparency, which is the object of the present invention, and excellent in flexibility, the total number of moles of tetracarboxylic dianhydride component is The alicyclic tetracarboxylic dianhydride, for example, the tetracarboxylic dianhydride represented by the above formula (C1) is preferably 90 mol% or more, more preferably 95 mol% or more, In particular, it is optimal that all (100 mol%) is a tetracarboxylic dianhydride represented by the above formula (C1).
Similarly, in order to obtain a resin thin film laminate having the above-mentioned low linear expansion coefficient, low retardation and high transparency and excellent flexibility, the fluorine-containing aromatic is used with respect to the total number of moles of the diamine component. The diamine, for example, the diamine represented by the formula (A1) is preferably 90 mol% or more, and more preferably 95 mol% or more. Moreover, the diamine represented by the said Formula (A1) may be sufficient as all (100 mol%) of a diamine component.

As an example of a suitable aspect, the polyimide used by this invention contains the monomer unit represented by following formula (1).

As the monomer unit represented by the above formula (1), those represented by the formula (1-1) or the formula (1-2) are preferable, and those represented by the formula (1-1) are more preferable.

According to the preferable aspect of this invention, the polyimide used by this invention contains the monomer unit represented by Formula (2). The polyimide used in the present invention may contain a monomer unit represented by the formula (1) and a monomer unit represented by the formula (2) at the same time.

As the monomer unit represented by the above formula (2), those represented by the formula (2-1) or the formula (2-2) are preferable, and those represented by the formula (2-1) are more preferable.

When the polyimide used in the present invention includes the monomer unit represented by the above formula (1) and the monomer unit represented by the formula (2), the molar ratio in the polyimide chain is represented by the formula (1). The monomer unit represented by the formula (2) is preferably contained at a ratio of 10: 1 to 1:10, more preferably 10: 1 to 3: 1.

The polyimide of the present invention includes an alicyclic tetracarboxylic dianhydride component containing a tetracarboxylic dianhydride represented by the above formula (C1), a diamine component containing a diamine represented by the formula (A1), and In addition to monomer units derived from, for example, monomer units represented by the above formulas (1) and (2), other monomer units may be included. The content ratio of the other monomer units is arbitrarily determined as long as the properties of the resin thin film laminate formed from the release layer forming composition and the resin thin film forming composition of the present invention are not impaired.
The ratio is derived from the alicyclic tetracarboxylic dianhydride component containing the tetracarboxylic dianhydride represented by the formula (C1) and the diamine component containing the diamine represented by the formula (A1). For example, the monomer unit represented by formula (1) or the number of moles of the monomer unit represented by formula (2), or the monomer unit represented by formula (1) and formula (2) Is preferably less than 20 mol%, more preferably less than 10 mol%, and even more preferably less than 5 mol%.

Examples of such other monomer units include, but are not limited to, monomer units having other polyimide structures represented by the formula (3).

In the formula (3), A represents a tetravalent organic group, preferably a tetravalent group represented by any of the following formulas (A-1) to (A-4). In the above formula (3), B represents a divalent organic group, preferably a divalent group represented by any of the following formulas (B-1) to (B-11). In each formula, * represents a bond. In the formula (3), when A represents a tetravalent group represented by any of the following formulas (A-1) to (A-4), B represents the above formulas (Y-1) to ( Y-34) may be a divalent group. Alternatively, in the formula (3), when B represents a divalent group represented by any of the following formulas (B-1) to (B-11), A represents the above formulas (X-1) to (X It may be a tetravalent group represented by any of -12).

When the monomer unit represented by Formula (3) is included in the polyimide used in the present invention, A and B include, for example, only a monomer unit composed of only one of the groups exemplified by the following formula. Alternatively, at least one of A and B may contain two or more monomer units selected from two or more groups exemplified below. In the following formula, * represents a bond.

In the polyimide used in the present invention, each monomer unit is bonded in an arbitrary order.

As a preferred example, a polyimide having a monomer unit represented by the above formula (1) has bicyclo [2,2,2] octane-2,3,5,6-tetracarboxylic acid as a tetracarboxylic dianhydride component. It can be obtained by polymerizing a dianhydride and a diamine represented by the following formula (4) as a diamine component in an organic solvent and imidizing the resulting polyamic acid.
In addition, when the polyimide used in the present invention has a monomer unit represented by the above formula (2), the polyimide may be 1,2,3,4-cyclobutanetetracarboxylic dianhydride as a tetracarboxylic dianhydride component. It is obtained by polymerizing a product and a diamine represented by the following formula (4) as a diamine component in an organic solvent and imidizing the resulting polyamic acid.
Furthermore, when the polyimide used by this invention has a monomer unit represented by the said Formula (2) in addition to the monomer unit represented by the said Formula (1), it is represented by Formula (1) and Formula (2). In addition to the above tetracarboxylic dianhydride as a tetracarboxylic dianhydride component, the polyimide containing each monomer unit has 1,2,3,4-cyclobutanetetracarboxylic dianhydride and the following formula as a diamine component: It is obtained by polymerizing the diamine represented by (4) in an organic solvent and imidizing the resulting polyamic acid.

Examples of the diamine represented by the above formula (4) include 2,2′-bis (trifluoromethyl) benzidine, 3,3′-bis (trifluoromethyl) benzidine, and 2,3′-bis (trifluoromethyl). Benzidine is mentioned.
Among them, the diamine component is represented by the following formula (4-1) from the viewpoint of lowering the linear expansion coefficient of the resin thin film laminate of the present invention and higher transparency of the resin thin film laminate. 2,2′-bis (trifluoromethyl) benzidine or 3,3′-bis (trifluoromethyl) benzidine represented by the following formula (4-2) is preferably used, and in particular, 2,2′- Bis (trifluoromethyl) benzidine is preferably used.

Moreover, the polyimide used by this invention contains the diamine represented by the alicyclic tetracarboxylic dianhydride component containing the tetracarboxylic dianhydride represented by the above-mentioned formula (C1), and a formula (A1). In addition to the monomer unit derived from the diamine component, for example, the monomer unit represented by the above formula (1) and the monomer unit represented by the formula (2), other monomer units represented by the above formula (3) When it has, the polyimide containing each monomer unit represented by Formula (1), Formula (2), and Formula (3) is one of the above-mentioned two types of tetracarboxylic dianhydrides as the tetracarboxylic dianhydride component. In addition, a tetracarboxylic dianhydride represented by the following formula (5), a diamine represented by the following formula (6) as a diamine component, and a diamine represented by the following formula (6) in an organic solvent. Polymer obtained by polymerization with Obtained by imidizing a click acid.

A in the above formula (5) and B in the formula (6) have the same meaning as A and B in the above formula (3), respectively.

Specifically, as the tetracarboxylic dianhydride represented by the formula (5), pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride 4,4 ′-(hexafluoroisopropylidene) diphthalic dianhydride, 11,11-bis (trifluoromethyl) -1H-difuro [3,4-b: 3 ′, 4′-i] xanthene- 1,3,7,9- (11H-tetraone), 6,6′-bis (trifluoromethyl)-[5,5′-biisobenzofuran] -1,1 ′, 3,3′-tetraone, 4, , 6,10,12-tetrafluorodifuro [3,4-b 3 ′, 4′-i] dibenzo [b, e] [1,4] dioxin-1,3,7,9-tetraone, 4,8-bis (trifluoromethoxy) benzo [1,2-c: 4 , 5-c ′] difuran-1,3,5,7-tetraone and N, N ′-[2,2′-bis (trifluoromethyl) biphenyl-4,4′-diyl] bis (1,3 Aromatic dicarboxylic acids such as dioxo-1,3-dihydroisobenzofuran-5-carboxamide); 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3 , 4-Tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic Acid dianhydride and 3,4-dicarboxy- Alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride; and aliphatics such as 1,2,3,4-butanetetracarboxylic dianhydride Although tetracarboxylic dianhydride is mentioned, it is not limited to these.
Among these, tetracarboxylic dianhydrides in which A in the formula (5) is a tetravalent group represented by any one of the above formulas (A-1) to (A-4) are preferable. , 11-bis (trifluoromethyl) -1H-difuro [3,4-b: 3 ′, 4′-i] xanthene-1,3,7,9- (11H-tetraone), 6,6′-bis (Trifluoromethyl)-[5,5′-biisobenzofuran] -1,1 ′, 3,3′-tetraone, 4,6,10,12-tetrafluorodifuro [3,4-b: 3 ′ , 4′-i] dibenzo [b, e] [1,4] dioxin-1,3,7,9-tetraone and 4,8-bis (trifluoromethoxy) benzo [1,2-c: 4, 5-c ′] difuran-1,3,5,7-tetraone can be mentioned as a preferred compound.

Examples of the diamine represented by the formula (6) include 2- (trifluoromethyl) benzene-1,4-diamine, 5- (trifluoromethyl) benzene-1,3-diamine, and 5- (trifluoromethyl). ) Benzene-1,2-diamine, 2,5-bis (trifluoromethyl) -benzene-1,4-diamine, 2,3-bis (trifluoromethyl) -benzene-1,4-diamine, 2,6 -Bis (trifluoromethyl) -benzene-1,4-diamine, 3,5-bis (trifluoromethyl) -benzene-1,2-diamine, tetrakis (trifluoromethyl) -1,4-phenylenediamine, 2 -(Trifluoromethyl) -1,3-phenylenediamine, 4- (trifluoromethyl) -1,3-phenylenediamine, 2-methoxy-1,4-pheny Diamine, 2,5-dimethoxy-1,4-phenylenediamine, 2-hydroxy-1,4-phenylenediamine, 2,5-dihydroxy-1,4-phenylenediamine, 2-fluorobenzene-1,4-diamine, 2,5-difluorobenzene-1,4-diamine, 2-chlorobenzene-1,4-diamine, 2,5-dichlorobenzene-1,4-diamine, 2,3,5,6-tetrafluorobenzene-1, 4-diamine, 4,4 ′-(perfluoropropane-2,2-diyl) dianiline, 4,4′-oxybis [3- (trifluoromethyl) aniline], 1,4-bis (4-aminophenoxy) Benzene, 1,3′-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, benzidine, 2-methylben Gin, 3-methylbenzidine, 2- (trifluoromethyl) benzidine, 3- (trifluoromethyl) benzidine, 2,2'-dimethylbenzidine (m-tolidine), 3,3'-dimethylbenzidine (o-tolidine) 2,3′-dimethylbenzidine, 2,2′-dimethoxybenzidine, 3,3′-dimethoxybenzidine, 2,3′-dimethoxybenzidine, 2,2′-dihydroxybenzidine, 3,3′-dihydroxybenzidine, 2 , 3'-dihydroxybenzidine, 2,2'-difluorobenzidine, 3,3'-difluorobenzidine, 2,3'-difluorobenzidine, 2,2'-dichlorobenzidine, 3,3'-dichlorobenzidine, 2,3 '-Dichlorobenzidine, 4,4'-diaminobenzanilide, 4-aminophenyl-4'-aminobenzoate Octafluorobenzidine, 2,2 ′, 5,5′-tetramethylbenzidine, 3,3 ′, 5,5′-tetramethylbenzidine, 2,2 ′, 5,5′-tetrakis (trifluoromethyl) benzidine, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) benzidine, 2,2 ′, 5,5′-tetrachlorobenzidine, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4 ′ -Bis (3-aminophenoxy) biphenyl, 4,4 '-{[3,3 "-bis (trifluoromethyl)-(1,1': 3 ', 1" -terphenyl) -4,4 "- Diyl] -bis (oxy)} dianiline, 4,4 ′-{[(perfluoropropane-2,2-diyl) bis (4,1-phenylene)] bis (oxy)} dianiline, and 1- (4- Aminophenyl) -2,3-dihydro- , 3,3-trimethyl-1H-indene-5 (or 6) amine and other aromatic diamines; 4,4′-methylenebis (cyclohexylamine), 4,4′-methylenebis (3-methylcyclohexylamine), isophoronediamine Trans-1,4-cyclohexanediamine, cis-1,4-cyclohexanediamine, 1,4-cyclohexanebis (methylamine), 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, , 6-bis (aminomethyl) bicyclo [2.2.1] heptane, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] decane, 1,3-diaminoadamantane, 2,2- Bis (4-aminocyclohexyl) propane, 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-pro Pandiamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, and 1,9-nonamethylene Examples include aliphatic diamines such as diamines, but are not limited thereto.
Among these, aromatic diamines in which B in the formula (6) is a divalent group represented by any one of the formulas (B-1) to (B-11) are preferable, that is, 2,2 ′. -Bis (trifluoromethoxy)-(1,1'-biphenyl) -4,4'-diamine [other name: 2,2'-dimethoxybenzidine], 4,4 '-(perfluoropropane-2,2- Diyl) dianiline, 2,5-bis (trifluoromethyl) benzene-1,4-diamine, 2- (trifluoromethyl) benzene-1,4-diamine, 2-fluorobenzene-1,4-diamine, 4, 4′-oxybis [3- (trifluoromethyl) aniline], 2,2 ′, 3,3 ′, 5,5 ′, 6,6′-octafluoro [1,1′-biphenyl] -4,4 ′ -Diamine [Alternative name: Octafluorobenzidine], 2, 3, 5, -Tetrafluorobenzene-1,4-diamine, 4,4 '-{[3,3 "-bis (trifluoromethyl)-(1,1': 3 ', 1" -terphenyl) -4,4 " -Diyl] -bis (oxy)} dianiline, 4,4 '-{[(perfluoropropane-2,2-diyl) bis (4,1-phenylene)] bis (oxy)} dianiline, and 1- (4 -Aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5 (or 6) amine may be mentioned as a preferred diamine.

<Synthesis of polyamic acid>
As described above, the polyimide used in the present invention is represented by the tetracarboxylic dianhydride component including the alicyclic tetracarboxylic dianhydride represented by the above formula (C1) and the above formula (A1). It is obtained by imidizing a polyamic acid obtained by reacting a diamine component containing a fluorine-containing aromatic diamine.
Specifically, for example, as a preferred example, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, and optionally 1,2,3,4-cyclobutanetetracarboxylic An acid dianhydride, a tetracarboxylic dianhydride component comprising a tetracarboxylic acid dihydrate represented by the above formula (5) if necessary, a diamine represented by the above formula (4), and optionally the above formula ( It is obtained by polymerizing a diamine component composed of the diamine component represented by 6) in an organic solvent and imidizing the resulting polyamic acid.
The reaction from the two components to the polyamic acid is advantageous in that it can proceed relatively easily in an organic solvent and no by-product is formed.

The charging ratio (molar ratio) of the diamine component in the reaction between the tetracarboxylic dianhydride component and the diamine component is appropriately set in consideration of the molecular weight of the polyamic acid and the polyimide obtained by subsequent imidization. However, with respect to the diamine component 1, the tetracarboxylic dianhydride component can usually be about 0.8 to 1.2, for example about 0.9 to 1.1, preferably about 0.1. It is about 95 to 1.02. Similar to the normal polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the polyamic acid produced.

The organic solvent used in the reaction between the tetracarboxylic dianhydride component and the diamine component is not particularly limited as long as it does not adversely affect the reaction and the produced polyamic acid dissolves. Specific examples are given below.
For example, m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 3- Methoxy-N, N-dimethylpropylamide, 3-ethoxy-N, N-dimethylpropylamide, 3-propoxy-N, N-dimethylpropylamide, 3-isopropoxy-N, N-dimethylpropylamide, 3-butoxy -N, N-dimethylpropylamide, 3-sec-butoxy-N, N-dimethylpropylamide, 3-tert-butoxy-N, N-dimethylpropylamide, γ-butyrolactone, N-methylcaprolactam, dimethylsulfoxide, tetra Methylurea, pyridine, dimethylsulfone, hexamethylsulfoxy Isopropyl alcohol, methoxymethyl pentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol Thor, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene Glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate mono Propyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, Methylcyclohexene, dipropyl ether, dihex Ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl acetate Ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, isopropyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, Examples include, but are not limited to, butyl 3-methoxypropionate, diglyme, and 4-hydroxy-4-methyl-2-pentanone. You may use these individually or in combination of 2 or more types.
Furthermore, even if the solvent does not dissolve the polyamic acid, it may be used by mixing with the above solvent as long as the produced polyamic acid does not precipitate. In addition, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyamic acid, it is preferable to use a dehydrated and dried organic solvent as much as possible.

As a method of reacting the tetracarboxylic dianhydride component and the diamine component in an organic solvent, a dispersion or solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred, and the tetracarboxylic dianhydride is added here. A method of adding a component as it is, or a method in which a tetracarboxylic acid component is dispersed or dissolved in an organic solvent, or a dispersion or solution in which a tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent. Examples thereof include a method of adding a diamine component and a method of alternately adding a tetracarboxylic dianhydride component and a diamine compound component, and any of these methods may be used.
Moreover, when the tetracarboxylic dianhydride component and / or the diamine component are composed of a plurality of types of compounds, they may be reacted in a premixed state, individually individually, or further individually. Low molecular weight substances may be mixed and reacted to form high molecular weight substances.

The temperature at the time of synthesizing the polyamic acid may be appropriately set in the range from the melting point to the boiling point of the solvent to be used, and can be selected, for example, from -20 ° C to 150 ° C. C. to 150.degree. C., usually about 0 to 150.degree. C., preferably about 0 to 140.degree.
Although the reaction time depends on the reaction temperature and the reactivity of the raw material, it cannot be defined unconditionally, but is usually about 1 to 100 hours.
The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, the total concentration of the tetracarboxylic dianhydride component and the diamine component in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 40% by mass. The initial stage of the reaction can be performed at a high concentration, and then an organic solvent can be added.

<Imidization of polyamic acid>
Examples of the method for imidizing the polyamic acid include thermal imidization in which the polyamic acid solution is heated as it is, and catalytic imidization in which a catalyst is added to the polyamic acid solution.
The temperature at which the polyamic acid is thermally imidized in the solution is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and it is preferable to carry out while removing water generated by the imidation reaction from the system.

The chemical (catalyst) imidization of polyamic acid is carried out by adding a basic catalyst and an acid anhydride to a polyamic acid solution, and igniting the system under a temperature condition of −20 to 250 ° C., preferably 0 to 180 ° C. This can be done by stirring.
The amount of the basic catalyst is 0.5 to 30 mol times, preferably 1.5 to 20 mol times the amide acid group of the polyamic acid, and the amount of the acid anhydride is 1 to 50 mol of the amide acid group of the polyamic acid. Double, preferably 2 to 30 mole times.

Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and 1-ethylpiperidine. Among them, pyridine and 1-ethylpiperidine have an appropriate basicity for proceeding with the reaction. Therefore, it is preferable.
Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated.
The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

In the polyimide resin used in the present invention, the dehydration cyclization rate (imidization rate) of the amic acid group is not necessarily 100%, and can be arbitrarily adjusted according to the use and purpose. Particularly preferably, it is 50% or more.

In the present invention, after filtering the reaction solution, the filtrate may be used as it is, or may be diluted or concentrated to form a release layer forming composition, and further, silicon dioxide or the like described later is further blended therein to form a resin thin film. A forming composition may be used. Thus, when filtered, not only can the contamination of the resulting resin thin film laminate be deteriorated in heat resistance, flexibility or linear expansion coefficient characteristics, but also effectively reduce the composition of the release layer, and A composition for forming a resin thin film can be obtained.

The polyimide used in the present invention is a gel permeation chromatography (GPC) polystyrene in consideration of the strength of the resin thin film laminate, the workability when forming the resin thin film laminate, the uniformity of the resin thin film laminate, and the like. The weight average molecular weight (Mw) in terms of conversion is preferably 5,000 to 200,000.

<Polymer recovery>
When the polymer component is recovered from the reaction solution of polyamic acid and polyimide and used, the reaction solution may be poured into a poor solvent and precipitated. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer precipitated in a poor solvent and collected by filtration can be dried by normal temperature or reduced pressure at room temperature or by heating.
In addition, when the operation (reprecipitation recovery step) in which the polymer collected by precipitation is redissolved in an organic solvent, reprecipitated and recovered (reprecipitation recovery step) is repeated 2 to 10 times, impurities in the polymer can be reduced. In this case, it is preferable to use three or more kinds of poor solvents such as alcohols, ketones, and hydrocarbons as the poor solvent because the purification efficiency is further increased.

The organic solvent for dissolving the resin component in the reprecipitation collection step is not particularly limited. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2- Pyrrolidone, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl Examples include ketones, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, and 4-hydroxy-4-methyl-2-pentanone. Two or more kinds of these solvents may be mixed and used.

[Silicon dioxide]
Silicon dioxide (silica) used in the resin thin film forming composition of the present invention is not particularly limited, but silicon dioxide in the form of particles, for example, an average particle diameter of 100 nm or less, for example, 5 nm to 100 nm, 5 nm to 60 nm, preferably 5 nm to 55 nm. From the viewpoint of obtaining a highly transparent thin film with good reproducibility, it is preferably 5 nm to 50 nm, more preferably 5 nm to 45 nm, still more preferably 5 nm to 35 nm, and further preferably 5 nm to 30 nm.
In the present invention, the average particle diameter of silicon dioxide particles is an average particle diameter value calculated from specific surface area values measured by a nitrogen adsorption method using silicon dioxide particles.

In particular, in the present invention, colloidal silica having the above average particle size can be suitably used, and silica sol can be used as the colloidal silica. As the silica sol, there can be used an aqueous silica sol produced by a known method using a sodium silicate aqueous solution as a raw material, and an organosilica sol obtained by substituting water as a dispersion medium of the aqueous silica sol with an organic solvent.
In addition, alkoxysilanes such as methyl silicate and ethyl silicate are obtained by hydrolysis and condensation in an organic solvent such as alcohol in the presence of a catalyst (for example, an alkali catalyst such as ammonia, an organic amine compound, or sodium hydroxide). Or a silica sol obtained by replacing the silica sol with another organic solvent can be used.
Among these, the present invention preferably uses an organosilica sol whose dispersion medium is an organic solvent.

Examples of the organic solvent in the above-described organosilica sol include: lower alcohols such as methyl alcohol, ethyl alcohol and isopropanol; linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide; N-methyl-2- Examples include cyclic amides such as pyrrolidone; ethers such as γ-butyrolactone; glycols such as ethyl cellosolve and ethylene glycol, acetonitrile, and the like. This substitution can be performed by a usual method such as a distillation method or an ultrafiltration method.
The viscosity of the organosilica sol is about 0.6 mPa · s to 100 mPa · s at 20 ° C.

Examples of commercially available organosilica sols include, for example, trade name MA-ST-S (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MT-ST (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.). ), Trade name MA-ST-UP (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MA-ST-M (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MA-ST- L (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST-S (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST (isopropanol-dispersed silica sol, Nissan Chemical Industries, Ltd.) Product name) IPA-ST-UP (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries Ltd.), product name IPA-ST- (Isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST-ZL (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name NPC-ST-30 (n-propyl cellosolve-dispersed silica sol, NISSAN CHEMICAL INDUSTRY CO., LTD.), Trade name PGM-ST (1-methoxy-2-propanol dispersed silica sol, NISSAN CHEMICAL INDUSTRY CO., LTD.), Trade name DMAC-ST (dimethylacetamide dispersed silica sol, NISSAN CHEMICAL INDUSTRY CO., LTD. Product name XBA-ST (xylene / n-butanol mixed solvent dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product name EAC-ST (ethyl acetate dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product Name PMA-ST (propylene glycol monomethyl ether acetate dispersed silica sol, Nissan Chemical Industries, Ltd.) ), Trade name MEK-ST (methyl ethyl ketone dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MEK-ST-UP (methyl ethyl ketone dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MEK-ST-L ( Examples thereof include, but are not limited to, methyl ethyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd., and trade name MIBK-ST (methyl isobutyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.).
In the present invention, silicon dioxide, for example, silicon dioxide as mentioned in the above product used as organosilica sol, may be used by mixing two or more kinds.

[Crosslinking agent]
The composition for forming a release layer and the composition for forming a resin thin film used in the present invention can further contain a crosslinking agent. In the case of using a crosslinking agent in the present invention, it is suitable to be blended only in either the release layer forming composition or the resin thin film forming composition, and among them, only in the resin thin film forming composition. It is preferable to blend a crosslinking agent.
The cross-linking agent used here is a compound composed only of hydrogen atoms, carbon atoms and oxygen atoms, or a compound composed only of these atoms and nitrogen atoms, and comprises a hydroxy group, an epoxy group and a carbon atom number of 1 to A crosslinking agent comprising a compound having two or more groups selected from the group consisting of 5 alkoxy groups and having a ring structure. By using such a crosslinking agent, a composition for forming a release layer that not only gives a resin thin film laminate excellent in solvent resistance and suitable for a substrate for flexible devices with good reproducibility, but also has improved storage stability. A composition for forming a resin thin film can be realized.
Among them, the total number of hydroxy groups, epoxy groups and alkoxy groups having 1 to 5 carbon atoms per compound in the crosslinking agent is preferably from the viewpoint of realizing the solvent resistance of the resulting resin thin film laminate with good reproducibility. From the viewpoint of realizing the flexibility of the resulting resin thin film laminate with good reproducibility, it is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less.

Specific examples of the ring structure of the crosslinking agent include aryl rings such as benzene, nitrogen-containing heteroaryl rings such as pyridine, pyrazine, pyrimidine, pyridazine, and 1,3,5-triazine, cyclopentane, cyclohexane, and cyclohexane. And cycloalkane rings such as heptane, cyclic amines such as piperidine, piperazine, hexahydropyrimidine, hexahydropyridazine, and hexahydro-1,3,5-triazine.

The number of ring structures per compound in the cross-linking agent is not particularly limited as long as it is 1 or more, but from the viewpoint of ensuring the solubility of the cross-linking agent in a solvent and obtaining a highly flat resin thin film laminate, 1 or 2 is preferred.
When two or more ring structures are present, the ring structures may be condensed with each other, and an alkane having 1 to 5 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, a propane-2,2-diyl group, etc. The ring structures may be bonded to each other through a linking group such as a diyl group.

The molecular weight of the crosslinking agent is not particularly limited as long as it has crosslinking ability and dissolves in the solvent to be used, but the solvent resistance of the resulting resin thin film laminate, the solubility of the crosslinking agent itself in an organic solvent, In consideration of availability, price, etc., it is preferably about 100 to 500, more preferably about 150 to 400.

The crosslinking agent may further have a group that can be derived from a hydrogen atom, a carbon atom, a nitrogen atom, and an oxygen atom, such as a ketone group or an ester group (bond).

Preferred examples of the crosslinking agent include compounds represented by the following formulas (K1) to (K5), and one preferred embodiment of the formula (K4) is a compound represented by the formula (K4-1). However, as one of preferable embodiments of the formula (K5), a compound represented by the formula (5-1) can be exemplified.

In the above formula, each of A ¹ and A ² independently represents an alkane-diyl group having 1 to 5 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, and a propane-2,2-diyl group. Among them, A ¹ is preferably a methylene group or an ethylene group, more preferably a methylene group, and A ² is preferably a methylene group or a propane-2,2-diyl group.

Each X is independently of each other a hydroxy group, an epoxy group (oxa-cyclopropyl group), or a methoxy group, an ethoxy group, a 1-propyloxy group, an isopropyloxy group, a 1-butyloxy group, a t-butyloxy group, etc. Represents an alkoxy group having 1 to 5 carbon atoms.
Among these, X is preferably an epoxy group in the formulas (K1) and (K5), and has 1 to 5 carbon atoms in the formulas (K2) and (K3) in consideration of the availability, price, etc. of the crosslinking agent. An alkoxy group is preferable, and a hydroxy group is preferable in the formula (K4).

In the formula (K4), each n represents the number of — (A ¹ -X) groups bonded to the benzene ring and is an integer of 1 to 5 independently of each other, preferably 2 to 3, more preferably 3.

In each compound, each A ¹ is preferably the same group, and each X is preferably the same group.

The compounds represented by the above formulas (K1) to (K5) are skeleton compounds such as aryl compounds, heteroaryl compounds, and cyclic amines having the same ring structure as the ring structure in these compounds, epoxy alkyl halide compounds, It can be obtained by reacting an alkoxy halide compound or the like with a carbon-carbon coupling reaction or an N-alkylation reaction, or hydrolyzing the resulting alkoxy moiety.

A commercial item may be used for a crosslinking agent, and what was synthesize | combined with the well-known synthesis | combining method may be used for it.
Commercially available products include CYMEL (registered trademark) 300, 301, 303LF, 303ULF, 304, 350, 3745, XW3106, MM-100, 323, 325, 327, 328, Same 385, Same 370, Same 373, Same 380, Same 1116, Same 1130, Same 1133, Same 1141, Same 1161, Same 1168, Same 3020, Same 202, Same 203, Same 1156, Same MB-94, Same MB- 96, MB-98, 247-10, 651, 658, 683, 683, 688, 1158, MB-14, MI-12-I, MI-97-IX, U-65 UM-15, U-80, U-21-511, U-21-510, U-216-8, U-227-8, U-1050-10, U-1052 -8, the same -1054, U-610, U-640, UB-24-BX, UB-26-BX, UB-90-BX, UB-25-BE, UB-30-B, U -662, U-663, U-1051, UI-19-I, UI-19-IE, UI-21-E, UI-27-EI, U-38-I, UI -20-E, 659, 1123, 1125, 5010, 1170, 1172, NF3041, and NF2000 (all made by Allnex); TEPIC (registered trademark) V, S, HP, Same L, same PAS, same VL, and same UC (manufactured by Nissan Chemical Industries, Ltd.), TM-BIP-A (manufactured by Asahi Organic Materials Co., Ltd.), 1,3,4,6-tetrakis ( Methoxymethyl) glycoluril (hereinafter abbreviated as TMG) (Tokyo Kasei) 4,4'-methylenebis (N, N-diglycidylaniline) (Aldrich), HP-4032D, HP-7200L, HP-7200, HP-7200H, HP-7200HH, HP- 7200HHH, HP-4700, HP-4770, HP-5000, HP-6000, HP-4710, EXA-4850-150, EXA-4850-1000, EXA-4816, and HP-820 (DIC Corporation), TG -G (Shikoku Chemicals Co., Ltd.)

Hereinafter, preferred specific examples of the crosslinking agent will be given, but the present invention is not limited thereto.

The amount of the crosslinking agent is appropriately determined according to the type of the crosslinking agent and the like, and thus cannot be defined unconditionally, but is usually based on the mass of the polyimide contained in the release layer forming composition or resin thin film formation. 50% by mass or less, preferably 100% by mass or less, from the viewpoint of ensuring the flexibility of the resulting resin thin film laminate and suppressing embrittlement relative to the total mass of the polyimide and silicon dioxide contained in the composition for use. From the viewpoint of ensuring the solvent resistance of the obtained resin thin film laminate, it is 0.1% by mass or more, preferably 1% by mass or more.

[Organic solvent]
The composition for forming a release layer and the composition for forming a resin thin film used in the present invention contain an organic solvent. This organic solvent is not specifically limited, For example, the thing similar to the specific example of the reaction solvent used at the time of preparation of the said polyamic acid and a polyimide is mentioned. More specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, γ- Examples include butyrolactone. In addition, an organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and γ-butyrolactone are preferable in view of obtaining a highly flat resin thin film laminate with high reproducibility.

[Composition for Release Layer Formation]
The composition for forming a release layer used in the present invention is a composition containing the heat-resistant polymer and an organic solvent, and optionally containing a crosslinking agent, and substantially contains silicon dioxide as described above. It is something that does not. The amount of solids and the viscosity in the composition for forming a release layer conform to the following composition for forming a resin thin film.

[Composition for resin thin film formation]
The composition for forming a resin thin film used in the present invention is a composition that contains the heat-resistant polymer, silicon dioxide, and an organic solvent, and may optionally contain a crosslinking agent. Here, the composition for forming a resin thin film is uniform and phase separation is not observed.
In the composition for forming a resin thin film, the blending ratio of the heat-resistant polymer and the silicon dioxide is preferably a mass ratio of heat-resistant polymer: silicon dioxide = 10: 1 to 1:10, more preferably 8 : 2 to 2: 8, for example, 7: 3 to 3: 7.
The solid content in the composition for forming a resin thin film is usually about 0.5 to 30% by mass, preferably about 5 to 25% by mass. When the solid content concentration is less than 0.5% by mass, the production efficiency of the resin thin film is lowered and the viscosity of the resin thin film forming composition is lowered, so that a coating film having a uniform surface can be obtained. Hateful. On the other hand, if the solid content concentration exceeds 30% by mass, the viscosity of the resin thin film forming composition becomes too high, and there is a possibility that the film forming efficiency is deteriorated and the surface uniformity of the coating film is also lacking. Here, the solid content (solid content concentration) means the total mass of components other than the organic solvent, and even a liquid monomer or the like is included in the weight as a solid content.
The viscosity of the composition for forming a resin thin film is appropriately set in consideration of the thickness of the resin thin film to be produced, etc. In particular, the object is to obtain a resin thin film having a thickness of about 5 to 50 μm with good reproducibility. In this case, the pressure is usually about 500 to 50,000 mPa · s at 25 ° C., preferably about 1,000 to 20,000 mPa · s.

<Other ingredients>
In addition, various organic or inorganic low-molecular or high-molecular compounds may be blended in the release layer forming composition and the resin thin film forming composition in order to impart processing characteristics and various functionalities. For example, a catalyst, an antifoaming agent, a leveling agent, a surfactant, a dye, a plasticizer, fine particles, a coupling agent, a sensitizer, and the like can be used. For example, the catalyst can be added for the purpose of reducing the retardation and linear expansion coefficient of the resin thin film laminate.

The release layer-forming composition is, for example, a polyimide obtained by the above-described method as a heat-resistant polymer, a crosslinking agent as necessary, and other components as necessary (various organic or inorganic low-molecular or high-molecular compounds ) Can be obtained by dissolving in the above-mentioned organic solvent.

The composition for forming a resin thin film includes, for example, a polyimide and silicon dioxide obtained by the above-described method as a heat-resistant polymer, a crosslinking agent as necessary, and other components as necessary (various organic or inorganic low molecules or Polymer compound) can be obtained by dissolving in the above-mentioned organic solvent. Alternatively, silicon dioxide may be added to the reaction solution after the polyimide is prepared, and the organic solvent may be further added as desired.
In addition, as mentioned above, when a crosslinking agent is used in the present invention, it is used in either the release layer forming composition or the resin thin film forming composition.

In the present invention, the resin contained in the release layer forming composition and the resin contained in the resin thin film forming composition are the same as described above from the viewpoint of not affecting the characteristics and the like. Preferably there is. In addition, silicon dioxide particles are further contained only in the resin thin film forming composition. In the case where these suitable conditions are provided, the preparation method of each composition is not particularly limited. Therefore, in the method of the present invention, for example, after first preparing a release layer forming composition, silicon dioxide particles are added to a part of the obtained release layer forming composition as described above, and if desired, organic By further adding a solvent, a composition for forming a release layer and a composition for forming a resin thin film can be easily prepared, and these can be used in the method of the present invention.

<Method for producing resin thin film laminate>
[Peeling layer forming step]
This step is a step of forming a release layer on the supporting substrate using the above-described release layer forming composition.
Specifically, by applying the release layer-forming composition on a support substrate, drying and heating to remove the organic solvent, it has excellent heat resistance, low retardation, excellent flexibility, and further transparency It is possible to obtain an exfoliation layer that can be easily exfoliated from a supporting substrate by at least one method selected from the group consisting of cutting with a knife, mechanical separation, and simultaneous peeling, while maintaining excellent performance of being excellent in properties. As a result, a flexible device substrate can be obtained.

Examples of the support substrate include plastic (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene resin, etc.), metal, stainless steel (SUS), wood, Paper, glass, a silicon wafer, a slate, etc. are mentioned.
In particular, from the viewpoint that existing equipment can be used, the supporting substrate to be applied is preferably glass or a silicon wafer, and since the resulting release layer exhibits good peelability, it should be glass. Further preferred. In addition, as a linear expansion coefficient of the support base material to apply, from a viewpoint of the curvature of the support base material after coating, Preferably it is 40 ppm / degrees C or less, More preferably, it is 30 ppm / degrees C or less.

The method for applying the composition for forming the release layer on the support substrate is not particularly limited, and examples thereof include a cast coating method, a spin coating method, a blade coating method, a dip coating method, a roll coating method, and a bar coating method. , Die coating method, ink jet method, printing method (letter plate, intaglio plate, planographic plate, screen printing, etc.) and the like, and these can be appropriately used according to the purpose.

The heating temperature is preferably 500 ° C. or lower, and more preferably 450 ° C. or lower. However, when the temperature exceeds 300 ° C., there may be a problem of yellowing. Even in this case, the ratio of the thickness of the release layer to the entire thickness of the resin thin film laminate obtained by the production method of the present invention is as follows. Since it is sufficiently small as described in (1), the influence on the characteristics is small. In addition, when the resin thin film forming composition is applied onto the formed release layer, the higher the final firing temperature, the smaller the proportion of the release layer dissolved in the resin thin film forming composition. When the temperature is 400 ° C., the release layer is difficult to dissolve. As a result, the boundary between the release layer and the resin thin film becomes clear. On the other hand, when the temperature is 300 ° C. or lower, a part of the release layer becomes a resin thin film forming composition. By dissolving, the boundary between the release layer and the resin thin film becomes a gradation, but in any case, the effect of the present invention is achieved.
Considering the heat resistance and linear expansion coefficient characteristics of the resulting release layer, the applied release layer forming composition is heated at 40 ° C. to 100 ° C. for 5 minutes to 2 hours, and then the heating temperature is gradually increased. Finally, it is desirable to heat at a temperature in the range of more than 175 ° C. to 450 ° C. for 30 minutes to 2 hours. Thus, by heating at a temperature of two or more stages of drying the solvent and promoting molecular orientation, the low thermal expansion characteristics can be expressed with higher reproducibility.
In particular, the applied composition for forming a release layer is heated at 40 ° C. to 100 ° C. for 5 minutes to 2 hours, then at a temperature exceeding 100 ° C. to 175 ° C. for 5 minutes to 2 hours, and then within a range from 175 ° C. to 450 ° C. It is preferable to heat at the inner temperature for 5 minutes to 2 hours.
Examples of the appliance used for heating include a hot plate and an oven. The heating atmosphere may be under air or under an inert gas such as nitrogen, and may be under normal pressure or under reduced pressure, and different pressures are applied at each stage of heating. May be.

In this step, a fine structure (intermediate layer) may be formed on the surface of the release layer by a coating technique from the viewpoint of further improving the adhesion between the release layer and the resin thin film formed thereafter. In that case, specifically, it is preferable to form a fine structure on the surface of the release layer before the release layer is cured, for example, after application of the release layer forming composition or in the course of subsequent stage heating.

The thickness of the release layer is appropriately determined in consideration of the type of the flexible device within a range of about 1 nm to 200 μm. However, in order to achieve the effects of the present invention, it is at least thicker than the diameter of the silica particles. It is necessary. In particular, assuming that the resin thin film laminate is used as a substrate for a flexible display, it is usually about 10 nm to 10 μm, preferably about 100 nm to 5 μm, and the desired thickness can be adjusted by adjusting the thickness of the coating film before heating. A release layer is formed.

[Resin thin film formation process]
This step is a step of forming a resin thin film on the release layer using the resin thin film forming composition of the present invention described above. This step can be said to be a step of forming a resin thin film laminate including a release layer and a resin thin film formed thereon on a supporting substrate.
Specifically, the thin film-forming composition is applied onto the release layer formed on the support substrate, dried and heated to remove the organic solvent, thereby providing high heat resistance and high transparency. In addition, it is possible to obtain a resin thin film having moderate flexibility, moderate linear expansion coefficient, and low retardation.
Moreover, in this process, when a part of peeling layer is melt | dissolved by the organic solvent contained in the composition for resin thin film formation, the resin thin film and the peeling layer adhere, and both adhesiveness becomes strong.

The coating method of the composition for forming a resin thin film on the release layer, the heating temperature, the apparatus used for heating, and the thickness of the resin thin film conform to the respective conditions described in the formation process of the release layer.

In the resin thin film laminate formed on the support substrate in this way, in order to realize easy peeling from the support substrate, the adhesion force of the resin thin film to the release layer is greater than the adhesion force of the release layer to the support substrate. Is preferably large.
Specifically, the adhesion between the release layer and the resin thin film is 0 to 1 (0 to 5% peelable) according to the CCJ series (JIS5400) classification, and the support substrate and the release layer Is preferably 5 (50% or more peelable) in the CCJ series (JIS5400) classification. The CCJ series is defined as a classification from 0 to 5, where 0 classification means that 0% of the square area can be removed, 1 classification means 1-5% of the square area, 2 classifications Is 6-10% of the square area, 3 is 11-25% of the square area, 4 is 26-50% of the square area, and 5 is 50% of the square area This means that each can be peeled off. In other words, on the condition of the cross-cut test according to JIS K5400, the number of square peels of the resin thin film with respect to the release layer is class 0-2, and the number of square peels of the release layer with respect to the support substrate is class 5 It is preferable that

[Step of obtaining a resin thin film laminate]
In this step, the release layer and the resin thin film are peeled together from the support substrate to obtain a resin thin film laminate.
The method of peeling the resin thin film laminate formed in this way from the support substrate is not particularly limited. For example, the resin thin film laminate is cooled together with the support substrate, and the resin thin film laminate is cut and peeled off. And a method of peeling by applying tension through a roll. In particular, as a method for peeling the resin thin film laminate from the supporting substrate in the present invention, at least one method selected from cutting with a knife, mechanical separation, and peeling can be applied.

Thus, according to the method of the present invention, since the adhesion between the release layer and the resin thin film is stronger than the adhesion between the release layer and the support substrate, the release layer and the resin thin film are integrated. It can be easily peeled off from the support base material to obtain a resin thin film laminate.
In the present invention, the thickness of the resin thin film laminate can be appropriately determined in consideration of the type of flexible device within the range of about 1 μm to 200 μm. The thickness of the release layer relative to the thickness of the resin thin film laminate (100%) is preferably 1 to 35%.

The resin thin film laminate obtained in one preferred embodiment of the present invention can achieve high transparency with a light transmittance of 75% or more at a wavelength of 400 nm.
Further, the resin thin film laminate can have a low coefficient of linear expansion of, for example, 60 ppm / ° C. or less, particularly 10 ppm / ° C. to 35 ppm / ° C. at 50 ° C. to 200 ° C., for example, at 200 ° C. to 250 ° C. The linear expansion coefficient can be as low as 80 ppm / ° C. or less, particularly 15 ppm / ° C. to 55 ppm / ° C., and has excellent dimensional stability during heating.
In particular, the resin thin film laminate is represented by a product of birefringence (difference between two in-plane orthogonal refractive indexes) and a film thickness (thickness of the laminate) when the wavelength of incident light is 590 nm. The in-plane retardation R ₀ and the two birefringences (difference between the two in-plane refractive indices and the refractive index in the thickness direction) when viewed from the cross-section in the thickness direction, thickness direction retardation R _th, expressed as an average value of the two phase difference obtained by multiplying the thickness), both of which features a very small. Resin thin film laminate obtained by the production method of the present invention, when the average film thickness (average thickness of the laminate) of 15 [mu] m ~ 40 [mu] m, the retardation _{R th} is less than 700nm in the thickness direction, for example 660nm or less, for example, 10nm ˜660 nm, in-plane retardation R ₀ is less than 4, eg 0.3 to 3.9, and birefringence Δn is very low, eg less than 0.02, eg 0.0003 to 0.019 .
Thus, retardation can be reduced in the resin thin film laminate obtained by the production method of the present invention.

Since the resin thin film laminate obtained by using the manufacturing method of the present invention described above has the above-mentioned characteristics, it satisfies each condition necessary as a base film of a flexible display substrate. Can be used particularly preferably. That is, the present invention is suitable as a method for manufacturing a flexible device substrate.

An example of manufacturing a flexible device using the manufacturing method of the present invention is shown in FIG.
As shown in FIG. 1, first, a release layer is formed on a support substrate, a resin thin film is formed on the release layer, and a resin thin film laminate is obtained. Then, after forming a functional layer on a resin thin film laminated body, these can be peeled together and a flexible device can be obtained.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

The meanings of the abbreviations used in the following examples are as follows.
<Acid dianhydride>
BODAxx: Bicyclo [2,2,2] octane-2,3,5,6-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride <diamine>
TFMB: 2,2′-bis (trifluoromethyl) benzidine <organic solvent>
GBL: γ-butyrolactone

In the examples, the apparatus and conditions used for sample preparation and physical property analysis and evaluation are as follows.
1) Measurement of number average molecular weight and weight average molecular weight The number average molecular weight (hereinafter abbreviated as Mn) and the weight average molecular weight (hereinafter abbreviated as Mw) of a polymer were measured by a device: Showdex GPC-101, manufactured by Showa Denko KK Column: KD803 and KD805, column temperature: 50 ° C., elution solvent: DMF, flow rate: 1.5 ml / min, calibration curve: standard polystyrene.
2) Linear expansion coefficient (CTE)
Using TMA Q400 manufactured by TA Instruments, the thin film (or laminate) is cut into a size of 5 mm wide and 16 mm long, first heated to 10 ° C./min and heated to 50 to 350 ° C. (first heating) Then, the temperature is lowered at 10 ° C./min and cooled to 50 ° C., and then heated at 50 ° C./min and heated to 50 to 420 ° C. (second heating). It calculated | required by measuring the value of the linear expansion coefficient (CTE [ppm / degrees C]) in ° C. Note that a load of 0.05 N was applied through the first heating, cooling, and second heating.
3) 5% weight loss temperature (Td _5% )
The 5% weight loss temperature (Td _5% [° C.]) is TGA Q500 manufactured by TA Instruments, and the temperature is increased from about 5 to 10 mg of a thin film (or laminate) to 50 to 800 ° C. at 10 ° C./min in nitrogen. And obtained by measuring.
4) Light transmittance (transparency) (T _{308 nm} , T _{400 nm} , T _{550 nm} ) and CIE b value (CIE b ^* )
Light transmittance (T _{308 nm} , T _{400 nm} , T _{550 nm} [%]) and CIE b value (CIE b ^* ) at wavelengths of 308 nm, 400 nm, and 550 nm were measured at room temperature using a SA4000 spectrometer manufactured by Nippon Denshoku Industries Co., Ltd. The measurement was performed using air as the reference.
5) Retardation ( _Rth , _R0 )
Thickness direction retardation (R _th ) and in-plane retardation (R ₀ ) were measured at room temperature using KOBURA 2100ADH manufactured by Oji Scientific Instruments.
In addition, thickness direction retardation ( _Rth ) and in-plane retardation ( _R0 ) are calculated by the following formula | equation.
R ₀ = (Nx−Ny) × d = ΔNxy × d
R _th = [(Nx + Ny) / 2−Nz] × d = [(ΔNxz × d) + (ΔNyz × d) / 2
Nx, Ny: Two in-plane orthogonal refractive indexes (Nx> Ny, Nx is also called the slow axis, and Ny is also called the fast axis)
Nz: Refractive index in the thickness (perpendicular) direction with respect to the surface d: Film thickness (thickness of the laminate)
ΔNxy: difference between two in-plane refractive indices (Nx−Ny) (birefringence)
ΔNxz: difference between in-plane refractive index Nx and thickness direction refractive index Nz (birefringence)
ΔNyz: difference between in-plane refractive index Ny and thickness direction refractive index Nz (birefringence)
6) Birefringence (Δn)
Using the thickness direction retardation (R _th ) obtained by the above <5) retardation>, the following formula was used.
Δn = [R _th / d (film thickness (layer thickness))] / 1000
7) Film thickness (thickness of laminate)
The film thickness of the obtained resin thin film and the thickness of the resin thin film laminate were measured with a thickness gauge manufactured by Teclock Co., Ltd.

[1] Preparation Example Preparation Example 1: Preparation of silica sol (GBL-M) In a 1000 mL round bottom flask, 350 g of methanol-dispersed silica sol manufactured by Nissan Chemical Industries, Ltd .: MA-ST-M (silica solid content concentration: 40.4) % By weight) and 419 g of γ-butyllactone. Then, the flask was connected to a vacuum evaporator to reduce the pressure in the flask, and immersed in a warm water bath at about 35 ° C. for 20 to 50 minutes, so that silica sol (GBL-M) in which the solvent was substituted from methanol to γ-butyllactone was reduced. 560.3 g was obtained (silica solid content concentration: 25.25% by mass).

[2] Synthesis Example Synthesis Example 1: Synthesis of Polyimide A (PI-A) In a 250 mL reaction three-necked flask equipped with a nitrogen inlet / outlet, a mechanical stirrer and a condenser, TFMB 25.61 g (0.08 mol) ) Thereafter, 173.86 g of GBL was added and stirring was started. Immediately after the diamine was completely dissolved in the solvent, 10 g (0.04 mol) of stirred BODAxx, 7.84 g (0.04 mol) of CBDA and 43.4 g of GBL were added and heated to 140 ° C. under nitrogen. . Thereafter, 0.348 g of 1-ethylpiperidine was added into the solution and heated to 180 ° C. for 7 hours under nitrogen. Finally, the heating was stopped and the reaction solution was diluted to 10% and kept stirring overnight. The polyimide reaction solution was added to 2000 g of methanol and stirred for 30 minutes, and then the polyimide solid was filtered to purify the polyimide. And this polyimide solid was stirred in 2000 g of methanol for 30 minutes, and the polyimide solid was filtered. The purification procedure for stirring and filtering the polyimide solid was repeated three times. The methanol residue in the polyimide was removed by drying in a vacuum oven at 150 ° C. for 8 hours, and finally 31.16 g of polyimide A was dried. The yield of polyimide A (PI-A) was 74% (Mw = 169,802, Mn = 55,308).

[3] Preparation of release layer forming composition and resin thin film forming composition, and production of resin thin film laminate (1)
Example 1: Formation of release layer At room temperature, 1 g of the polyimide (PI-A) of Synthesis Example 1 dissolved in GBL solvent so as to be 8% by mass was slowly filtered under pressure through a 1 μm filter, and the release layer A forming composition was obtained. Thereafter, the composition is coated on a glass support substrate, fired at 50 ° C. for 30 minutes, 140 ° C. for 30 minutes, and 200 ° C. for 60 minutes, and further fired at 300 ° C. for 60 minutes. did. Thus, a transparent polyimide film as a release layer was formed on the glass supporting substrate. The optical and thermal properties are shown in Table 1.

Example 2: Formation of Release Layer Using the release layer forming composition prepared in Example 1, this was coated on a glass support substrate, and in an air atmosphere at a temperature of 50 ° C for 30 minutes, at 140 ° C for 30 minutes and A transparent polyimide film as a release layer was obtained on a glass supporting substrate in the same manner as in Example 1 except that baking was performed at 200 ° C. for 60 minutes and then baking was further performed at 400 ° C. for 60 minutes. The optical and thermal properties are shown in Table 1.

Example 3: Preparation of composition for resin thin film formation At room temperature, 1 g of polyimide (PI-A) of Synthesis Example 1 dissolved in GBL solvent so as to be 10% by mass was slowly filtered under pressure through a 5 μm filter. did. The filtrate is then added to 9.241 g of silica sol (GBL-M) (18-23 nm SiO ₂ nanoparticles dispersed in GBL at 25.25%), mixed for 30 minutes, The composition was maintained overnight to obtain a resin thin film forming composition.
This composition for forming a resin thin film was coated on a glass supporting substrate, and was subjected to an air atmosphere at a temperature of 50 ° C. for 30 minutes, a temperature of 140 ° C. for 30 minutes and a temperature of 200 ° C., and a vacuum atmosphere of −99 kpa. A resin thin film was obtained by baking at 280 ° C. for 60 minutes. Table 1 shows optical and thermal characteristics of the obtained resin thin film.

Example A: Production of Resin Thin Film Laminate A The resin thin film-forming composition prepared in Example 3 was coated on the release layer obtained in Example 1, and 140 minutes at a temperature of 50 ° C. for 30 minutes in an air atmosphere. C. for 30 minutes at 200.degree. C. for 60 minutes at 200.degree. C. and in a vacuum atmosphere of -99 kpa for 60 minutes at 280.degree. C. to obtain a resin thin film (polyimide A / silica sol composite resin thin film).
Then, the peeling layer and resin thin film which were formed on the glass support base material were isolate | separated (peeled) from the glass support base material by mechanical cutting, and the resin thin film laminated body A was obtained.
Table 1 shows the optical and thermal characteristics of the resin thin film laminate A.

5 and 6 are cross-sectional views (cross section TEM) of the resin thin film laminate A, FIG. 7 is a (a) surface (resin thin film side) of the resin thin film laminate A, and (b) an interface between the release layer and the resin thin film. And (c) Raman IR spectra on the back surface (peeling layer side) are shown. 6A is an enlarged view of the vicinity of “mixing” in FIG. 5, and FIG. 6B shows the component composition of each layer constituting the laminate, in which [001] is an intermediate layer, [ 002] indicates a resin thin film (polyimide + SiO ₂ ), and [003] indicates a release layer (DBL).
According to the cross section TEM of FIGS. 5 and 6, formation of an intermediate layer was confirmed at the interface between the formed release layer and the resin thin film, and the thickness thereof was about 300 nm.
Further, as shown in the Raman IR spectrum of FIG. 7, (b) the IR spectrum at the interface between the release layer and the resin thin film almost matches the shape of the IR spectrum at (c) the back surface, and the interface is derived from at least the release layer. As a result.

Example B: Production of Resin Thin Film Laminate B Resin thin film laminate B was prepared in the same manner as in Example A except that the resin thin film forming composition prepared in Example 3 was coated on the release layer obtained in Example 2. A thin film laminate B was obtained.

8 and FIG. 9 are cross-sectional views (cross section TEM) of the resin thin film laminate B, FIG. 10 is the resin thin film laminate B (a) surface (resin thin film side), (b) the interface between the release layer and the resin thin film, And (c) The Raman IR spectrum of the back surface (peeling layer side) is shown, respectively. FIG. 9 (a) is an enlarged view of the vicinity of the interface in FIG. 8, and FIG. 9 (b) shows the component composition of each layer constituting the laminate, where [001] is a release layer (DBL), [002] indicates a resin thin film (polyimide + SiO ₂ ).
According to the cross section TEM of FIGS. 8 and 9, the interface between the formed release layer and the resin thin film is clearly separated compared to Example A, and the thickness of the intermediate layer in this case is very thin, about 1 nm or less. Met.
Also, as shown in the Raman IR spectrum of FIG. 10, (b) the IR spectrum at the interface between the release layer and the resin thin film is almost identical to the (c) IR spectrum on the back surface, and the interface is considered to originate from the release layer. As a result.

The cross-sectional schematic diagram of the resin thin film laminated bodies A and B obtained in the said Example is shown in FIG.2 and FIG.3.
As shown in FIG. 2, the resin thin film laminates A and B are formed on the supporting base (G1) with a release layer (L II), an intermediate layer (L III), a resin thin film (polyimide A / silica sol composite resin thin film) ( It was confirmed to have a laminated structure in the order of LI). And as shown in FIG. 3, resin thin film laminated body A and B were obtained by isolate | separating (peeling) these laminated structures from a support base material (G1). 2 and 3, an element layer such as an electrode is denoted by LIV.
Here, the release layer (L II), the resin thin film (polyimide A / silica sol composite resin thin film) (LI), and the intermediate layer formed between them each have a polymer network structure shown in FIG. It is thought that. This network means that two polymers and nanosilica are bonded to each other by van der Waals force or hydrogen bond, thereby increasing the adhesive force between the resin thin film and the release layer. The intermediate layer can be obtained not only from the release layer but also from a resin thin film. This is because when the resin thin film is formed, the upper surface of the release layer can be partially dissolved by the solvent contained in the resin thin film forming composition. And thereby, an intermediate | middle layer can be obtained when a peeling layer and a resin thin film react again (thermal imidation).

As shown in Table 1, the resin thin film laminate A obtained by the production method of the present invention has a low coefficient of linear expansion [ppm / ° C.] (50 to 200 ° C.) and transmits light at 400 nm and 550 nm after curing. It was confirmed that the rate [%] was high, the yellowness represented by the CIE b * value was small, and the retardation was suppressed to a low value.

In addition, the resin thin film laminate A of the present invention obtained in the above examples does not break even when held with both hands and bent at an acute angle (about 30 degrees), and has high flexibility required for a flexible display substrate. Was.

[4] Manufacture of resin thin film laminate (2)
Using the composition for forming a release layer prepared in <Example 1: Formation of release layer> and the composition for forming a resin thin film prepared in <Example 3: preparation of a composition for forming a resin thin film> A resin thin film laminate was manufactured at
(A) Preparation of Crosslinking Agent-Containing Release Layer Forming Composition Into the release layer forming composition prepared in <Example 1: Formation of Release Layer>, CYMEL (registered trademark) 303 (manufactured by allnex) is added to the composition. A composition for forming a release layer containing a crosslinking agent was prepared by mixing at 30 phr with respect to the mass of polyimide (PI-A) contained in the product.
(B) Preparation of a composition for forming a resin thin film containing a crosslinking agent In the composition for forming a resin thin film prepared in <Example 3: Preparation of a composition for forming a resin thin film>, CYMEL 303 is added to a polyimide ( PI-A) and silica sol (GBL-M) were mixed at 30 phr with respect to the total mass to prepare a composition for forming a resin thin film forming a crosslinking agent.
(I) After forming a release layer on a glass supporting substrate using the release layer forming composition, a resin thin film was formed on the release layer using the resin thin film forming composition.
(Ii) After forming a release layer on the glass support substrate using the release layer forming composition, a resin thin film was formed on the release layer using the crosslinking agent blending / resin thin film forming composition. .
(Iii) After forming a release layer on a glass support substrate using the composition for forming a crosslinker and release layer, a resin thin film was formed on the release layer using the composition for forming a resin thin film.
(Iv) After forming a release layer on a glass support substrate using the composition for forming a crosslinker / release layer, a resin thin film on the release layer using the composition for forming a crosslinker / resin thin film Formed.
After the resin thin film was formed, the release layer and the resin thin film were peeled together from the glass supporting substrate by mechanical cutting, and the peelability was evaluated according to the following criteria.
<Peelability evaluation>
A: Completely separated (peeled) from the glass supporting substrate (almost 100%)
Δ: difficult to separate from glass support substrate (5-50%)
×: Cannot be separated from the glass supporting substrate (<5%)

In each example, the firing conditions were 120 ° C. for 20 minutes, 140 ° C. for 20 minutes, 200 ° C. for 30 minutes, and 250 ° C. for 60 minutes in an air atmosphere.
The obtained results are shown in Table 2.

As shown in Table 2, when a crosslinking agent is blended in either the release layer forming composition or the resin thin film forming composition, the resin thin film laminate can be easily peeled from the glass support substrate. Was confirmed.

Claims (15)

1. A method for producing a resin thin film laminate,
   Forming a release layer on the support substrate using the release layer-forming composition containing the heat-resistant polymer A and an organic solvent;
   A step of forming a resin thin film on the release layer using a composition for forming a resin thin film containing the heat-resistant polymer B and an organic solvent;
   Peeling the support layer together with the release layer and the resin thin film to obtain a resin thin film laminate,
   The resin thin film forming composition further includes silicon dioxide particles having an average particle diameter calculated from a specific surface area value measured by a nitrogen adsorption method of 100 nm or less, provided that
   The release layer forming composition does not contain silicon dioxide particles,
   Production method.
2. The manufacturing method according to claim 1, wherein the heat-resistant polymer A and the heat-resistant polymer B are the same polymer.
3. The heat-resistant polymer A and the heat-resistant polymer B are each independently at least one polymer selected from polyimide, polybenzoxazole, polybenzobisoxazole, polybenzimidazole, and polybenzothiazole. Manufacturing method.
4. The heat-resistant polymer A and the heat-resistant polymer B are each independently reacted with a tetracarboxylic dianhydride component containing an alicyclic tetracarboxylic dianhydride and a diamine component containing a fluorine-containing aromatic diamine. The manufacturing method of Claim 1 which is a polyimide obtained by imidating the polyamic acid obtained.
5. The manufacturing method of Claim 4 with which the said alicyclic tetracarboxylic dianhydride contains the tetracarboxylic dianhydride represented by Formula (C1).
   

   

   [Wherein B ¹ represents a tetravalent group selected from the group consisting of formulas (X-1) to (X-12).
   

   

   (In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.)
6. The manufacturing method of Claim 4 with which the said fluorine-containing aromatic diamine contains the diamine represented by a formula (A1).
   

   

   (Wherein B ² represents a divalent group selected from the group consisting of formulas (Y-1) to (Y-34)).
   

   

   

   

   

   

   (In the formula, * represents a bond.)
7. The manufacturing method of Claim 4 in which the said polyimide contains the monomer unit represented by Formula (1), the monomer unit represented by Formula (2), or both monomer units.
   

   
8. The production method according to claim 1, wherein the composition for forming a resin thin film contains the heat-resistant polymer B and the silicon dioxide particles in a mass ratio of 7: 3 to 3: 7.
9. The manufacturing method according to claim 1, wherein the silicon dioxide particles have an average particle diameter of 60 nm or less.
10. The method according to claim 1, wherein either one of the composition for forming a release layer or the composition for forming a resin thin film further contains a crosslinking agent.
11. 2. The method according to claim 1, wherein the curing is by heat or ultraviolet rays.
12. The adhesiveness between the release layer and the resin thin film is peelable from 0 to 5% according to the CCJ series (JIS5400) classification, and the adhesiveness between the support substrate and the release layer is CCJ series (JIS5400). ) 50% or more peelable by classification,
    The manufacturing method according to claim 1.
13. The manufacturing method according to claim 1, wherein the release layer has a thickness of 100 μm to 1 nm.
14. The manufacturing method according to claim 1, wherein the step of obtaining the resin thin film laminate is performed using a method selected from cutting with a knife, mechanical separation, and peeling.
15. The flexible substrate manufactured by the manufacturing method as described in any one of Claims 1 thru | or 14.
    

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