TW202319445A - Polyamic acid, polyamic acid composition, polyimide, polyimide film, laminate, production method for laminate, and electronic device - Google Patents

Abstract

According to the present invention, a polyamic acid includes a structural unit represented by general formula (1) and has a fluorine atom content of no more than 5 weight%. In general formula (1), R1 and R2 each independently represent a hydrogen atom, a monovalent aliphatic group, or a monovalent aromatic group, and X1 represents a bivalent organic group. According to the present invention, a polyamic acid composition contains an organic solvent and a polyamic acid that includes a structural unit represented by general formula (1) and has a fluorine atom content of no more than 5 weight%. According to the present invention, a polyimide is an imide compound of a polyamic acid that includes a structural unit represented by general formula (1) and has a fluorine atom content of no more than 5 weight%.

Description

Polyamide acid, polyamide acid composition, polyimide, polyimide film, laminate, method for producing laminate, and electronic device

The present invention relates to a polyamide acid, a polyamide acid composition, a polyimide, a polyimide film, a laminate, a method for manufacturing the laminate, and an electronic device. The present invention further relates to an electronic device material using polyimide, a thin film transistor (TFT) substrate, a flexible display substrate, a color filter, a printed matter, an optical material, an image display device (more specifically, a liquid crystal Display devices, organic EL (Electroluminescence, electroluminescence), electronic paper, etc.), 3D displays, solar cells, touch panels, transparent conductive film substrates, and replacement materials for components currently using glass.

With the rapid development of displays such as liquid crystal displays, organic EL, and electronic paper, or electronic devices such as solar cells and touch panels, thinning, lightening, and flexibility of devices continue to progress. In these devices, polyimide is used instead of a glass substrate as a substrate material.

In these devices, various electronic components, such as thin film transistors or transparent electrodes, are formed on the substrate, and the formation of these electronic components requires a high-temperature process. Polyimide has sufficient heat resistance to adapt to high-temperature processes, and its coefficient of thermal expansion (CTE) is also close to that of glass substrates or electronic components, so it is not easy to generate internal stress, and is suitable for substrate materials such as flexible displays.

In general, aromatic polyimides are colored in yellowish brown due to the formation of intramolecular conjugation or charge transfer (CT) complexes. Light, so the substrate is not required to have transparency, and the previous aromatic polyimide has been used. However, when light emitted from a display element passes through a substrate such as a transparent display, bottom-emitting organic EL, or liquid crystal display, or for making a full-scale display (notchless) of a smartphone, etc. When a sensor or a camera module is disposed on the back of a substrate, the substrate is also required to have high optical characteristics (more specifically, transparency, etc.).

Based on such a background, a material having heat resistance equivalent to conventional aromatic polyimides, less coloring and excellent transparency has been sought.

It is known to use aliphatic monomers to suppress the formation of CT complexes in order to reduce the coloring of polyimides (Patent Documents 1 and 2), and to use monomers with a skeletal skeleton to improve transparency ( Patent Document 3), and a technique for improving transparency by using a monomer having a fluorine atom (Patent Document 4).

Although the polyimides described in Patent Documents 1 and 2 have high transparency and low CTE, due to their aliphatic structure, their thermal decomposition temperature is relatively low, making them difficult to apply to high-temperature processes for forming electronic components. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-29177 [Patent Document 2] Japanese Patent Laid-Open No. 2012-41530 [Patent Document 3] Taiwan Patent Application Publication No. 201713726 [Patent Document 4] International Publication No. 2019/195148

[Problem to be solved by the invention]

The polyimide described in Patent Document 3 has high transparency and high heat resistance due to the introduction of a fennel skeleton. However, since the polyimide described in Patent Document 3 has a high coefficient of thermal expansion (CTE), the support and the polyimide may be separated due to heating and cooling when the polyimide film is formed on the support to obtain a laminate. The internal stress generated at the interface of the imide film tends to increase. Therefore, if the polyimide described in Patent Document 3 is used to form a layered body, the layered body is likely to be warped, which may make it difficult to apply to electronic devices.

Also, with regard to the technology described in Patent Document 4, it is also difficult to reduce the internal stress between the support and the polyimide film (hereinafter, it may be simply described as "internal stress"), and it is excellent in transparency and heat resistance. of polyimide.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a polyimide with reduced internal stress and excellent transparency and heat resistance, and a polyamic acid as a precursor thereof. Furthermore, the object of the present invention is also to provide a product or member that requires heat resistance and transparency and is manufactured using the polyimide and polyamic acid. In particular, the object of the present invention is to provide a product or member in which the polyimide film of the present invention is formed on the surface of inorganic substances such as glass, metal, metal oxide, and single crystal silicon. [Technical means to solve the problem]

<Aspects of the present invention> The present invention includes the following aspects.

[1] A polyamic acid comprising a structural unit represented by the following general formula (1) and having a fluorine atom content of 5% by weight or less.

[chemical 1]

In the above general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and ^X1 represents a divalent organic group.

[2] The polyamic acid described in the above [1], wherein in the above general formula (1), R ¹ and R ² both represent hydrogen atoms.

[3] The polyamic acid as described in the above [1] or [2], wherein in the above general formula (1), ^X is selected from a divalent organic group represented by the following chemical formula (2-1), and one or more of the group consisting of divalent organic groups represented by the following general formula (2-2).

[Chem 2]

In the above-mentioned general formula (2-2), Y ^is selected from the divalent organic group represented by the following chemical formula (3-1), the divalent organic group represented by the following chemical formula (3-2), the following chemical formula The divalent organic group represented by (3-3), the divalent organic group represented by the following chemical formula (3-4), the divalent organic group represented by the following chemical formula (3-5), and the following chemical formula ( 3-6) One or more of the group consisting of the divalent organic groups represented.

[Chem 3]

[4] The polyamic acid described in any one of the above [1] to [3], further comprising a structural unit represented by the following general formula (4).

[chemical 4]

In the above general formula (4), ^R3 and ^R4 independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, ^X2 represents a divalent organic group, and ^Y2 is selected from the following chemical formula (5 The tetravalent organic group represented by -1), the tetravalent organic group represented by the following chemical formula (5-2), the tetravalent organic group represented by the following chemical formula (5-3), and the tetravalent organic group represented by the following chemical formula (5- 4) More than one of the group formed by the represented tetravalent organic groups.

[chemical 5]

[5] The polyamic acid according to any one of the above [1] to [4], wherein the fluorine atom content is less than 1% by weight.

[6] A polyamic acid composition comprising the polyamic acid described in any one of [1] to [5] above, and an organic solvent.

[7] The polyamic acid composition according to the above [6], further comprising an imidization accelerator.

[8] The polyamic acid composition according to the above [7], wherein the amount of the imidization accelerator is 10 parts by weight or less with respect to 100 parts by weight of the polyamic acid.

[9] A polyimide which is an imide of the polyamic acid described in any one of the above [1] to [5].

[10] The polyimide as described in [9] above, wherein the 1% weight loss temperature is 500° C. or higher.

[11] The polyimide according to the above [9] or [10], which has a glass transition temperature of 420°C or higher.

[12] A polyimide film comprising the polyimide described in any one of [9] to [11] above.

[13] The polyimide film according to the above [12], which has a yellowness of 25 or less.

[14] A laminate comprising a support and the polyimide film as described in [12] or [13] above.

[15] The laminate as described in [14] above, wherein the support is a glass substrate, The internal stress between the polyimide film and the glass substrate is 40 MPa or less.

[16] A method for manufacturing a laminate, which is a method for manufacturing a laminate having a support and a polyimide film, By coating the polyamic acid composition described in any one of the above-mentioned [6] to [8] on a support, a coating film comprising the above-mentioned polyamic acid is formed, and the above-mentioned coating film The above-mentioned polyamic acid is imidized by heating.

[17] An electronic device comprising the polyimide film as described in [12] or [13] above, and an electronic element arranged on the polyimide film. [Effect of Invention]

The polyimide produced by using the polyamic acid of the present invention reduces internal stress and has excellent transparency and heat resistance. Therefore, the polyimide produced by using the polyamic acid of the present invention is suitable as a material for electronic devices that require transparency and heat resistance and are manufactured through high-temperature processes.

Hereinafter, preferred embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

First, terms used in this specification will be described. "Structural unit" means a repeating unit that constitutes a polymer. "Polyamic acid" is a polymer including a structural unit represented by the following general formula (6) (hereinafter, may be described as "structural unit (6)"). In addition, in this specification, polyamide ester (polyamide acid alkyl ester, polyamide acid aryl ester, etc.) is also described as "polyamide acid" other than polyamide acid.

[chemical 6]

In the general formula (6), R5 ^{and R6} independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and ^A1, for example, represents a tetracarboxylic dianhydride residue (derived from tetracarboxylic dianhydride A quaternary organic group), A ² represents, for example, a diamine residue (a divalent organic group derived from diamine).

The content of the structural unit (6) relative to all the structural units constituting the polyamic acid is, for example, 50 mol% to 100 mol%, preferably 60 mol% to 100 mol%, more preferably 70 mol%. More than 100 mole %, more preferably 80 mole % to 100 mole %, more preferably 90 mole % to 100 mole %, and may be 100 mole %.

"1% weight reduction temperature" refers to the measurement temperature at which the weight of polyimide at the measurement temperature of 150° C. is reduced by 1% by weight relative to the weight of the above standard (100% by weight). The measuring method of 1% weight reduction temperature is the same method as the following examples or with reference to the methods of the following examples.

"m/z" is a measured value that can be read from the horizontal axis of a mass spectrum as a measurement result of mass analysis, and refers to "the dimensionless quantity obtained by dividing the ion mass by the unified atomic mass unit (Dalton)" A dimensionless quantity obtained as the absolute value of the charge of the ion".

Hereinafter, "system" may be appended to the name of the compound to collectively refer to the compound and its derivatives. When adding "is" to the name of the polymer to indicate the name of the polymer, it means that the repeating unit of the polymer is derived from the compound or its derivatives. In addition, tetracarboxylic dianhydride may be described as "acid dianhydride". Moreover, unless otherwise specified, the component illustrated in this specification, a functional group, etc. may be used individually or in combination of 2 or more types.

<A preferred embodiment of the present invention> The polyamic acid of the present embodiment includes a structural unit represented by the following general formula (1) (hereinafter, may be described as "structural unit (1)"), and has a fluorine atom content of 5% by weight or less.

[chemical 7]

In the general formula (1), R ¹ and R ² each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X ¹ represents a divalent organic group. In order to facilitate imidization, R ¹ and R ² are each independently preferably a hydrogen atom, a methyl group or an ethyl group, and both R ¹ and R ² more preferably represent a hydrogen atom. Hereinafter, unless otherwise specified, a structural unit in which both R ¹ and R ² in the general formula (1) represent a hydrogen atom is taken as the structural unit (1).

-11,9'-[9H]茀]-1,3,7,9-四酮(以下，有時記載為「SFDA」)之部分結構。亦即，結構單元(1)具有SFDA殘基作為上述通式(6)中之A ¹。 Structural unit (1) has a structure derived from spiro[11H-difluoro[3,4-b:3',4'-i]𠮿

- Partial structure of 11,9'-[9H] fennel]-1,3,7,9-tetraketone (hereinafter sometimes referred to as "SFDA"). That is, the structural unit (1) has an SFDA residue as A ¹ in the above general formula (6).

The polyamic acid of this embodiment contains the structural unit (1) and the fluorine atom content is 5% by weight or less. Therefore, the polyimide produced by using the polyamic acid of this embodiment reduces internal stress, and has transparency and heat resistance. excellent. The reason for this is presumed as follows.

骨架而具有剛性結構，故不僅適合用作玻璃轉移溫度較高(耐熱性優異)之聚醯亞胺之原料(單體)，而且適合用作低CTE之聚醯亞胺之原料(單體)。又，SFDA由於茀骨架而適合用作高透明性之聚醯亞胺之原料(單體)。又，因包含結構單元(1)之聚醯胺酸於主鏈具有𠮿

骨架，並且於側鏈具有茀骨架，故使用包含結構單元(1)之聚醯胺酸製造之聚醯亞胺膜呈現出低相位差性。SFDA due to 𠮿

The skeleton has a rigid structure, so it is not only suitable as a raw material (monomer) of polyimide with a high glass transition temperature (excellent heat resistance), but also suitable as a raw material (monomer) of polyimide with low CTE . Also, SFDA is suitable as a raw material (monomer) of highly transparent polyimide due to its skeleton. Also, since the polyamic acid comprising the structural unit (1) has a 𠮿

Skeleton, and has a fennel skeleton in the side chain, so the polyimide film made of polyamide acid containing the structural unit (1) exhibits low retardation.

On the other hand, according to the research of the inventors of the present invention, it has been found that if SFDA and fluorine-containing monomers are used in combination as monomers for synthesizing polyamic acid, the alignment between the polymer chains of polyamic acid will decrease. And the tendency of CTE to become higher. On the other hand, since the fluorine atom content rate of the polyamic acid of this embodiment is 5 weight% or less, the fall of the alignment property between polymer chains is suppressed.

Therefore, the polyamic acid of this embodiment has SFDA residues that contribute to low CTE, and the fluorine atom content is 5% by weight or less, so it can reduce the time required to form a polyimide film on a support to obtain a laminated body. generated internal stress. Therefore, the polyimide manufactured using the polyamic acid of this embodiment can reduce internal stress.

Moreover, since the polyamic acid of this embodiment has the SFDA residue which contributes to transparency and heat resistance, the polyimide manufactured using the polyamic acid of this embodiment is excellent in transparency and heat resistance.

In order to further reduce the internal stress, the fluorine atom content of the polyamic acid of this embodiment (hereinafter sometimes referred to as "polyamic acid (1)") is preferably less than 1% by weight, more preferably less than 1% by weight. 0.5% by weight, more preferably less than 0.1% by weight, particularly preferably substantially 0% by weight (the polyamic acid (1) does not contain residues derived from fluorine-containing monomers). Furthermore, the fluorine atom content rate (unit: weight %) is the ratio of the weight of fluorine atoms to the total weight of polyamic acid. Polyamic acid-based polyadducts of diamine and tetracarboxylic dianhydride, the total weight of diamine and tetracarboxylic dianhydride before polymerization is equal to the weight of polyamic acid after polymerization. That is, the fluorine atom content of polyamic acid is obtained by dividing the "total weight of fluorine atoms contained in the monomers used to form polyamic acid" by the "total weight of monomers used to form polyamic acid" The resulting value is multiplied by 100. Therefore, the fluorine atom content rate of polyamic acid can be calculated based on the following formula.

[Formula 1]

In the above formula, n _i is the amount of diamine component i (unit: mole), and n _j is the amount of tetracarboxylic dianhydride j (unit: mole). M _i is the molecular weight of diamine component i, and M _j is the molecular weight of tetracarboxylic dianhydride j. F _i is the number of fluorine atoms contained in one molecule of the diamine component i, and F _j is the number of fluorine atoms contained in one molecule of tetracarboxylic dianhydride j. In addition, 19.00 is the atomic weight of fluorine. For example, using 0.05 mol of 2,2'-bis(trifluoromethyl)benzidine (molecular weight: 320.2, number of fluorine atoms: 6) and 0.95 mol of 4-aminophenyl-4-aminobenzidine Ester (molecular weight: 228.3, number of fluorine atoms: 0) was used as diamine, and 0.3 mole of SFDA (molecular weight: 472.4, number of fluorine atoms: 0) and 0.7 mole of 3,3',4,4'- Biphenyltetracarboxylic dianhydride (molecular weight: 294.2, number of fluorine atoms: 0) is polymerized as tetracarboxylic dianhydride. The fluorine atom content of polyamic acid is 100×19.00×(0.05×6)/(0.05 × 320.2 + 0.95 × 228.3 + 0.3 × 472.4 + 0.7 × 294.2) = 0.98% by weight.

The structural unit (1) has an SFDA residue and a diamine residue (a divalent organic group represented by X ¹ in the general formula (1)). In order to further reduce the internal stress, as the diamine providing X ¹ in the general formula (1), a diamine not containing a fluorine atom is preferable.

Examples of diamines that do not contain fluorine atoms include: p-phenylenediamine (hereinafter, sometimes referred to as "PDA"), 4-aminophenyl 4-aminobenzoate (hereinafter, sometimes referred to as "PDA"), 4-BAAB"), 4,4'-diaminobenzylaniline (hereinafter, sometimes referred to as "DABA"), 1,4-bis(4-aminobenzyloxy)benzene (hereinafter, Sometimes described as "BABB"), N,N'-(1,4-phenylene)bis(4-aminobenzamide) (hereinafter sometimes referred to as "PBAB"), terephthalic acid Bis(4-aminophenyl) ester (hereinafter sometimes referred to as "BATP"), N,N'-bis(4-aminophenyl) terephthalamide (hereinafter sometimes referred to as " DATA"), 1,3-bis(3-aminopropyl)tetramethyldisiloxane (hereinafter sometimes referred to as "PAM-E"), 1,4-cyclohexanediamine, m-phenylene Amine, 9,9-bis(4-aminophenyl) fluorine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether Phenylbenzene, m-toluidine, o-toluidine, 4,4'-bis(4-aminophenoxy)biphenyl, 2-(4-aminophenyl)-6-aminobenzo Azole, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-methylenebis(cyclohexylamine) and their derivatives These may be used alone, or two or more of them may be used.

In order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, ^X in the general formula (1) is preferably selected from PDA residues, 4-BAAB residues, DABA residues, and BABB residues. residue, PBAB residue, BATP residue and DATA residue in the group consisting of one or more.

The PDA residue is a divalent organic group represented by the following chemical formula (2-1). The 4-BAAB residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-1) as one of the general formula (2-2) ^Y1 . The DABA residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-2) as ^Y1 in the general formula (2-2) . The BABB residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-3) as ^Y1 in the general formula (2-2) . The PBAB residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-4) as ^Y in the general formula (2-2) . The BATP residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-5) as ^Y1 in the general formula (2-2) . The DATA residue is a divalent organic group represented by the following general formula (2-2), and has a divalent organic group represented by the following chemical formula (3-6) as ^Y1 in the general formula (2-2) .

[chemical 8]

[chemical 9]

In order to obtain polyimide with better heat resistance, X ¹ in the general formula (1) is preferably a PDA residue. In order to obtain polyimides with better transparency, ^X in the general formula (1) is preferably at least one selected from the group consisting of 4-BAAB residues, BABB residues and BATP residues, more preferably is the 4-BAAB residue. In order to obtain polyimides that can further reduce internal stress, X in the general formula ( ¹ ) is preferably more than one selected from the group consisting of DABA residues, PBAB residues and DATA residues, more preferably DATA residues.

In order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, it is selected from PDA residues, 4-BAAB residues, DABA residues, BABB residues, PBAB residues, BATP residues and DATA residues The content rate of one or more residues in the group formed by the group relative to all diamine residues constituting the polyamic acid (1) (total content rate when two or more types are included) is preferably 30 mo Mole% or more, more preferably 40 mole% or more, more preferably 50 mole% or more, and more preferably 60 mole% or more, can also be 70 mole% or more, 80 mole% or more or 90 mole% Mole% or more, can also be 100 mole%.

In addition, in order to impart appropriate adhesion to inorganic materials (for example, glass substrates, etc.), the polyamide acid (1) preferably contains PAM-E residues, and it is more preferable that the PAM-E residues are relatively The content of all diamine residues in the amino acid (1) is 0.01 mol % or more and 1 mol % or less.

When synthesizing polyamic acid (1), acid dianhydrides other than SFDA can also be used as monomers. In order to further reduce internal stress, acid dianhydrides other than SFDA are preferably acid dianhydrides that do not contain a fluorine atom.

Examples of acid dianhydrides that do not contain fluorine atoms include: pyromellitic dianhydride (hereinafter, sometimes referred to as "PMDA"), 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter, sometimes referred to as "BPDA"), 9,9-bis(3,4-dicarboxyphenyl) fluorine dianhydride (hereinafter, sometimes referred to as "BPAF"), 4,4'-oxodiphthalic acid Phthalic anhydride (hereinafter sometimes referred to as "ODPA"), 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 2,2' ,3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and their derivatives, which can be used alone, Alternatively, two or more types may be used.

In order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, polyamic acid (1) preferably comprises a polyimide selected from the group consisting of PMDA residues, BPDA residues, BPAF residues and ODPA residues. One or more of the group as acid dianhydride residues other than SFDA residues. That is, in order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, the polyamic acid (1) preferably further includes a structural unit represented by the following general formula (4) (hereinafter, It is described as "structural unit (4)").

[chemical 10]

In the general formula (4), R3 ^{and R4} independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, ^X2 represents a divalent organic group, and ^Y2 is selected from the following chemical formula (5- 1) The quadrivalent organic group represented by the following chemical formula (5-2), the tetravalent organic group represented by the following chemical formula (5-3), and the quadrivalent organic group represented by the following chemical formula (5-4 ) represented by one or more of the group consisting of tetravalent organic groups.

[chemical 11]

The PMDA residue is a tetravalent organic group represented by chemical formula (5-1). The BPDA residue is a tetravalent organic group represented by chemical formula (5-2). The BPAF residue is a tetravalent organic group represented by chemical formula (5-3). The ODPA residue is a tetravalent organic group represented by chemical formula (5-4).

In general formula (4), preferable groups of R ³ , R ⁴ and X ² are, for example, the same as those exemplified as preferable groups of R ¹ , R ² and X ¹ in general formula (1), respectively.

In order to obtain polyimide with further reduced internal stress and excellent transparency and heat resistance, the content of SFDA residues relative to all acid dianhydride residues constituting polyamic acid (1) is preferably 5 mole % Above, more preferably at least 10 mol%, more preferably at least 15 mol%, even more preferably at least 20 mol%, may be at least 30 mol%, at least 40 mol%, or at least 50 mol% The above may be 100 mol%.

In order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, one or more residues selected from the group consisting of PMDA residues, BPDA residues, BPAF residues and ODPA residues are relative to The content of all acid dianhydride residues constituting the polyamic acid (1) (total content when two or more of them are included) is preferably 5 mol% or more, more preferably 10 mol% or more, Furthermore, it is more preferably 20 mol% or more, and still more preferably 30 mol% or more, and may be 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% %above. Also, in order to obtain a polyimide that further reduces internal stress and has better transparency and heat resistance, one or more residues selected from the group consisting of PMDA residues, BPDA residues, BPAF residues, and ODPA residues The content rate relative to the total acid dianhydride residues constituting the polyamic acid (1) (total content rate when two or more types are included) is preferably 95 mol% or less, more preferably 90 mol% the following.

In order to obtain a polyimide that further reduces internal stress and is more excellent in transparency and heat resistance, the polyamic acid (1) preferably contains BPDA residues as acid dianhydride residues other than SFDA residues. In the case where polyamide acid (1) contains BPDA residues, in order to obtain polyimide with further reduced internal stress and better transparency and heat resistance, the mass ratio of SFDA residues to BPDA residues (SFDA residues/BPDA residues) is preferably 10/90 or more and 50/50 or less, more preferably 10/90 or more and 40/60 or less, more preferably 10/90 or more and 35/65 or less, and even more preferably 10/90 or more Above 90 and below 30/70.

The polyamic acid (1) may only include the structural unit (1) as a structural unit, or may only include the structural unit (1) and the structural unit (4) as the structural unit, or may include other than the structural unit (1) and the structural unit Structural units other than (4) (other structural units) are regarded as structural units. In order to obtain a polyimide with further reduced internal stress and excellent transparency and heat resistance, the content of the structural unit (1) relative to all structural units constituting the polyamic acid (1) is preferably 5 mol% or more , more preferably at least 10 mol%, further preferably at least 15 mol%, even more preferably at least 20 mol%, may also be at least 30 mol%, at least 40 mol%, or at least 50 mol% , can also be 100 mole%.

In the case where the polyamic acid (1) contains the structural unit (4), in order to obtain a polyimide with further reduced internal stress and excellent transparency and heat resistance, relative to the entirety of the polyamic acid (1) The structural unit, the total content of the structural unit (1) and the structural unit (4) is preferably from 60 mol% to 100 mol%, more preferably from 70 mol% to 100 mol%, and still more preferably More than 80 mol% to 100 mol%, more preferably 90 mol% to 100 mol%, may be 100 mol%.

In order to obtain a polyimide with further reduced internal stress and excellent transparency and heat resistance, the polyamic acid (1) preferably satisfies the following condition 1, more preferably satisfies the following condition 2, and still more preferably satisfies Condition 3 below. Condition 1: Polyamic acid (1) contains BPDA residues as acid dianhydride residues other than SFDA residues, and does not contain residues derived from fluorine-containing monomers. Condition 2: the above condition 1 is met, and the polyamic acid (1) contains residues selected from PDA residues, 4-BAAB residues, DABA residues, BABB residues, PBAB residues, BATP residues and DATA residues One or more diamine residues in the group. Condition 3: The above condition 2 is satisfied, and the mass ratio of SFDA residues to BPDA residues (SFDA residues/BPDA residues) is 10/90 or more and 35/65 or less.

The polyamic acid (1) can be synthesized by a well-known general method, for example, diamine and tetracarboxylic dianhydride can be reacted in an organic solvent. An example of a specific synthesis method of polyamide acid (1) will be described. First, diamine is dissolved or dispersed in an organic solvent in a slurry state in an inert gas atmosphere such as argon gas or nitrogen gas to prepare a diamine solution. Then, tetracarboxylic dianhydride is added to the above-mentioned diamine solution after being dissolved or dispersed in an organic solvent in a slurry form, or in a solid state.

When using diamine and tetracarboxylic dianhydride to synthesize polyamic acid (1), by adjusting the amount of diamine (when multiple diamines are used, the amount of each diamine) and tetracarboxylic acid The amount of acid dianhydride (when multiple kinds of tetracarboxylic dianhydrides are used, the amount of matter of each tetracarboxylic dianhydride), the desired polyamic acid (1) (diamine and tetracarboxylic acid di anhydride polymers). The molar fraction of each residue in polyamic acid (1) is, for example, consistent with the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of polyamic acid (1) . Moreover, the polyamic acid (1) containing plural kinds of tetracarboxylic dianhydride residues and plural kinds of diamine residues can also be obtained by blending two kinds of polyamic acids. The reaction of diamine and tetracarboxylic dianhydride, that is, the temperature condition of the synthesis reaction of polyamic acid (1) is not specifically limited, For example, it is the range of 20 to 150 degreeC. The reaction time of the synthesis reaction of the polyamic acid (1) is, for example, in a range of not less than 10 minutes and not more than 30 hours.

The organic solvent used in the synthesis of polyamic acid (1) is preferably a solvent capable of dissolving the tetracarboxylic dianhydride and diamine used, more preferably a solvent capable of dissolving the polyamic acid (1) to be produced . Examples of organic solvents used in the synthesis of polyamic acid (1) include: urea-based solvents such as tetramethylurea and N,N-dimethylethylurea; urea-based solvents such as dimethylurea Solvents; diphenylsulfone, tetramethylsulfonium and other solvents; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethyl Amide-based solvents such as acetamide, N-methyl-2-pyrrolidone (NMP), 3-methoxy-N,N-dimethylacrylamide (MPA), hexamethylphosphoryl triamide, etc. ;Ester-based solvents such as γ-butyrolactone;Halogenated alkyl-based solvents such as chloroform and methylene chloride;Aromatic hydrocarbon-based solvents such as benzene and toluene;Phenol-based solvents such as phenol and cresol;Kone-based solvents such as cyclopentanone; Tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, p-cresol methyl ether and other ether solvents . These solvents are usually used alone, but may be used in combination of two or more of them as necessary. In order to improve the solubility and reactivity of polyamic acid (1), the organic solvent used in the synthesis reaction of polyamic acid (1) is preferably selected from amide-based solvents, ketone-based solvents, and ester-based solvents One or more solvents in the group consisting of ether-based solvents are more preferably amide-based solvents (more specifically, DMF, DMAC, NMP, MPA, etc.). Also, the synthesis reaction of polyamic acid (1) is preferably carried out under an inert gas atmosphere such as argon or nitrogen.

The weight average molecular weight of polyamic acid (1) is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 20,000 to 500,000, still more preferably in the range of 30,000 to 200,000, but it depends on its use. When the weight average molecular weight is 10,000 or more, it is easy to use the polyamic acid (1) or the polyimide obtained by using the polyamic acid (1) as a coating film or a polyimide film (film). On the other hand, if the weight-average molecular weight is 1,000,000 or less, sufficient solubility with respect to the solvent is exhibited, so a coated film or polyimide film with a smooth surface and uniform thickness can be obtained by using the following polyamic acid composition . The weight average molecular weight used here means the polyethylene oxide conversion value measured using the gel permeation chromatography (GPC).

Also, as a method of controlling the molecular weight of polyamic acid (1), there may be mentioned a method of making either an acid dianhydride or a diamine excessive, or a monofunctional compound such as phthalic anhydride or aniline. A method of quenching the reaction by reacting with an anhydride or amine. When polymerizing with an excess of either acid dianhydride or diamine, a polyimide film having sufficient strength can be obtained if the feeding molar ratio thereof is between 0.95 and 1.05. Furthermore, the ratio of the total amount of diamines used in the synthesis of the molar ratio-based polyamic acid (1) to the total amount of dianhydrides used in the synthesis of the polyamic acid (1) Ratio (total substance amount of diamine/total substance amount of acid dianhydride). Moreover, the coloring of the polyimide obtained using polyamic acid (1) can also be further reduced by terminal-capping with phthalic anhydride, maleic anhydride, aniline, etc.

The polyamic acid composition of this embodiment contains polyamic acid (1) and an organic solvent. The organic solvent contained in the polyamic acid composition may, for example, be the organic solvent exemplified as the organic solvent that can be used in the synthesis reaction of the above-mentioned polyamic acid (1), and is preferably selected from amide-based solvents, One or more solvents in the group consisting of ketone solvents, ester solvents, and ether solvents are more preferably amide solvents (more specifically, DMF, DMAC, NMP, MPA, etc.). When the polyamic acid (1) is obtained by the above-mentioned method, the reaction solution (solution after reaction) itself can also be used as the polyamic acid composition of this embodiment. Moreover, the polyamic acid composition of this embodiment can also be prepared by dissolving solid polyamic acid (1) obtained by removing a solvent from a reaction solution in an organic solvent. In addition, the content rate of the polyamic acid (1) in the polyamic acid composition of this embodiment is not specifically limited, For example, it is 1 weight% or more 80 weight% with respect to the polyamic acid composition whole quantity the following.

In addition, the polyamic acid composition of this embodiment may contain an imidization accelerator and/or a dehydration catalyst in order to shorten heating time and express a characteristic.

It does not specifically limit as said imidization accelerator, A tertiary amine can be used. The tertiary amine is preferably a heterocyclic tertiary amine. As a preferable specific example of a heterocyclic tertiary amine, pyridine, picoline, quinoline, isoquinoline, imidazoles etc. are mentioned. As said dehydration catalyst, acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride etc. are mentioned as a preferable specific example.

From the viewpoint of shortening the heating time and the viewpoint of performance characteristics, the amount of the imidization accelerator is preferably from 0.1 to 10 parts by weight, more preferably not less than 10 parts by weight, based on 100 parts by weight of polyamic acid (1). It is not less than 0.5 parts by weight and not more than 5 parts by weight. Also, from the viewpoint of shortening the heating time and the viewpoint of performance characteristics, the amount of the dehydration catalyst is preferably from 0.1 parts by weight to 10 parts by weight, more preferably 0.5 parts by weight or more and 5 parts by weight or less.

As the imidization accelerator, imidazoles are preferred. In addition, in this specification, imidazoles refer to the compound which has 1, 3- oxadiazole ring (1, 3- oxadiazole ring structure). The imidazoles added to the polyamic acid composition of this embodiment are not particularly limited, for example, 1H-imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecane Alkyl imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methyl Imidazole, 1-benzyl-2-phenylimidazole, etc. Among them, preferably 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, more preferably 1,2-dimethylimidazole, 1- Benzyl-2-methylimidazole.

The content of imidazoles is preferably from 0.005 mole to 0.1 mole, more preferably from 0.01 mole to 0.08 mole, and even more preferably 0.015 mole relative to 1 mole of the amide group of polyamide acid (1). More than 0.050 mole and less than 0.050 mole. By containing more than 0.005 mol of imidazoles, the film strength and transparency of polyimide can be improved, and by keeping the content of imidazoles at 0.1 mol or less, the storage stability of polyamic acid (1) can be maintained , and improve heat resistance. To explain the improvement of transparency, it is known that a polymerization solvent such as NMP forms a complex based on hydrogen bonds with the carboxyl group of polyamic acid (1). May remain in the polyimide film and cause coloring due to oxidation or decomposition. It is considered that if imidazoles are added, the imidazoles coordinate to the carboxyl group of polyamide acid (1) to promote imidization, so that NMP and the like become less likely to remain in the polyimide film, and at the same time, the process of thermal imidization The decomposition of the polyamide acid (1) is also suppressed, so the transparency is improved. In addition, in this specification, "the amide group of polyamic acid (1)" means the amide group produced|generated by the polymerization reaction of diamine and tetracarboxylic dianhydride.

Also, imidization is promoted by adding imidazoles to polyamic acid, and in-plane alignment is induced starting from the imidized rigid unit in the initial stage of thermal imidization. However, if imidazoles are added to polyamic acids including BPDA and PDA, which are highly aligned without using imidazoles, the imidazoles will act as plasticizers and instead disturb the alignment of molecular chains. . On the other hand, since polyamic acid (1) has SFDA residue, it can reduce internal stress even if imidazoles are added.

The mixing method of polyamic acid (1) and imidazoles is not particularly limited. From the viewpoint of the ease of controlling the molecular weight of the polyamic acid (1), it is preferable to add imidazoles to the polyamic acid (1) after polymerization. At this time, the imidazoles can be directly added to the polyamic acid (1), or the imidazoles can be dissolved in a solvent in advance, and the solution can be added to the polyamic acid (1). The adding method is not particularly limited. The polyamic acid composition of this embodiment can also be prepared by adding imidazoles to a solution (solution after reaction) containing the polymerized polyamic acid (1).

In the polyamic acid composition of this embodiment, various organic or inorganic low-molecular-weight compounds or high-molecular-weight compounds can also be formulated as additives. As additives, for example, plasticizers, antioxidants, dyes, surfactants, leveling agents, silicones, fine particles, sensitizers and the like can be used. Microparticles include organic microparticles including polystyrene, polytetrafluoroethylene, etc., or inorganic microparticles including colloidal silicon oxide, carbon, layered silicate, etc., which may also have a porous structure or a hollow structure. Also, the function and form of the microparticles are not particularly limited, and may be, for example, pigments, fillers, or fibrous particles.

As the above-mentioned plasticizer, a compound that is dissolved in the organic solvent used for the polymerization of the polyamic acid (1) and exists in a liquid form during imidization is preferable. Also, in order to impart sufficient molecular mobility to the polyamic acid (1) during imidization, the plasticizer is preferably non-volatile at low temperatures. Therefore, the boiling point of the plasticizer is preferably 50°C or higher, more preferably 100°C or higher, and still more preferably 150°C or higher. Also, in order to impart sufficient molecular mobility to the polyamic acid (1) during imidization, the plasticizer preferably does not have a decomposition temperature below the boiling point.

From the viewpoint of imparting sufficient molecular mobility to the polyamic acid (1) and avoiding the decomposition of the plasticizer itself, the amount of the plasticizer is preferable relative to 100 parts by weight of the polyamic acid (1). It is 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, more preferably 0.05 to 10 parts by weight, still more preferably 0.05 to 5 parts by weight.

Plasticizers can not only improve the molecular movement of polyamic acid (1) when it is dehydrated and ring-closed to form polyimide, but can also impart functions such as glass transition temperature adjustment or flame retardancy. As a plasticizer, for example, 1 type or 2 or more types can be used suitably selected from well-known plasticizers.

In order to impart sufficient molecular mobility to polyamic acid (1), the plasticizer is preferably one selected from the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic dibasic esters. above.

Preferred examples of phosphorus-containing compounds include: phosphoric acid compounds, phosphorous acid compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine compounds, phosphine oxide compounds, phosphine compounds, phosphazene compounds, compounds etc. The phosphorus-containing compound may also be an ester body or a condensate of the compounds listed above, may also contain a ring structure, and may form a salt with an amine or the like. In addition, among these phosphorus-containing compounds, there are also those in a tautomeric relationship like phosphorous acid-based compounds and phosphonic acid-based compounds, and may exist in any state.

Specific examples of phosphoric acid-based compounds include: trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate , tricresyl phosphate, tris(xylene) phosphate, tris(isopropylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylylene diphenyl phosphate, diphenyl ( 2-Ethylhexyl) ester, di(isopropylphenyl)phenyl phosphate, monoisodecyl phosphate, 2-acryloxyethyl acid phosphate, 2-methacryloxyethyl acid phosphate Ester, diphenyl-2-acryloxyethyl phosphate, diphenyl-2-methacryloxyethyl phosphate, melamine phosphate, dimelamine phosphate, bisphenol A bis(diphenyl phosphate ), tris(β-chloropropyl) phosphate, etc.

Specific examples of phosphorous acid-based compounds include: triphenyl phosphite, tris(nonylphenyl) phosphite, tricresyl phosphite, triethyl phosphite, triisobutyl phosphite, Tris(2-ethylhexyl) phosphate, tridecyl phosphite, trilauryl phosphite, tri(tridecyl) phosphite, diphenyl phosphite, diethyl phosphite, dibutyl phosphite Dimethyl phosphite, diphenyl phosphite mono(2-ethylhexyl) ester, diphenyl phosphite monodecyl ester, diphenyl phosphite mono(tridecyl) ester, trithiosulfide Trilauryl phosphate, diethyl hydrogen phosphite, bis(2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphate, diphenyl hydrogen phosphite, tetraphenyl di Propylene glycol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, triphosphite (2,4-di-tert-butylphenyl) ester, tri-isodecyl phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4 ,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, etc.

Condensed phosphoric acid ester is mentioned as said condensate. Specific examples of condensed phosphoric acid esters include trialkyl polyphosphate, resorcinol polyphenylphosphate, resorcinol poly(di-2,6-xylyl)phosphate, terephthalate Phenolic poly(2,6-xylyl) phosphate, etc. Examples of commercially available condensed phosphoric acid esters include "CR-733S" manufactured by Daihachi Chemical Industry Co., Ltd., "CR-741" manufactured by Daihachi Chemical Industry Corporation, and "FP-600" manufactured by ADEKA Corporation. .

Specific examples of phosphazene-based compounds include phenoxycyclophosphazene ("FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.), cyclic cyanophenoxyphosphazene ("FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.), and cyclic cyanophenoxyphosphazene ("Fushimi Pharmaceutical Co., Ltd." FP-300"), etc.

The polyalkylene glycol may, for example, be polypropylene glycol or polyethylene glycol.

Specific examples of aliphatic dibasic acid esters include: dibutyl adipate, diisobutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate , Diisodecyl adipate, Bis[2-(2-butoxyethoxy)ethyl] adipate, Bis(2-ethylhexyl) azelate, Dibutyl sebacate , bis(2-ethylhexyl) sebacate, diethyl succinate, etc.

Moreover, a plasticizer may be a low molecular weight organic compound or a thermoplastic resin as long as it can exhibit a plasticizing effect. Examples of the aforementioned low-molecular-weight organic compounds include organic compounds with a molecular weight of about 1,000 or less, such as phthalimide, N-phenylphthalimide, N-glycidyl Phthalimide compounds such as phthalimide, N-hydroxyphthalimide, cyclohexylthiophthalimide, etc.; Maleimide-based compounds such as imide and 2,2'-(ethylenedioxy)bis(ethylmaleimide). As said thermoplastic resin, polyimide or polyamide etc. which have an asymmetric structure are mentioned.

Examples of the above-mentioned antioxidant include phenolic compounds, preferably phenolic compounds that are dissolved in the organic solvent used for the polymerization of polyamic acid (1) and exist in liquid form during imidization. . In terms of suppressing the coloring of the polyimide film, it is desirable to remain during imidization, so the boiling point of the phenolic compound is preferably 50°C or higher, more preferably 100°C or higher, and still more preferably 150°C. ℃ or more. Moreover, it is preferably a phenolic compound that does not have a decomposition temperature below the boiling point.

The phenolic compound may, for example, be a hindered type, a semi-hindered type, or a less hindered type, and specifically, dibutylhydroxytoluene, 1,3,5-tris(3,5 -Di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, acrylic acid 2-tert-butyl-4-methyl-6-(2-hydroxy-3-th Tributyl-5-methylbenzyl)phenyl ester, etc.

Phenolic compounds mainly capture peroxy radicals, convert them into hydroperoxides, and function as primary antioxidants to inhibit the auto-oxidation of polymers, so they have the function of inhibiting the coloring caused by polymer oxidation. Furthermore, coloring by oxidation of polyimide can be suppressed further by combining a phenolic compound with a phosphite ester etc. which have the function of the secondary antioxidant which converts a hydroperoxide into a stable alcohol compound. For example, coloring of polyimide can be suppressed effectively by using a phosphite in the range of 10 equivalents or more with respect to a phenolic compound.

In order to fully obtain the antioxidant effect, the amount of the phenolic compound is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, relative to 100 parts by weight of polyamic acid (1). , and more preferably not less than 0.02 parts by weight and not more than 1 part by weight. The phenolic compound may be pre-dissolved in an organic solvent before polymerization of the polyamic acid (1), or may be added to the polyamic acid solution after polymerization.

In order to maintain the transparency of the polyimide film and improve the heat resistance, nano-silica particles can also be used as the above-mentioned additive, and polyamic acid (1) can be compounded with nano-silica particles. From the viewpoint of maintaining the transparency of the polyimide film, the average primary particle size of the nano-silica particles is preferably less than 200 nm, more preferably less than 100 nm, and more preferably less than 50 nm. below 30 nm. On the other hand, from the viewpoint of securing the dispersibility in the polyamic acid (1), the average primary particle size of the nano-silica particles is preferably 5 nm or more, more preferably 10 nm or more. As a method for compounding polyamic acid (1) and nano-silica particles, known methods can be used, for example, the use of organosilicon sol obtained by dispersing nano-silica particles in an organic solvent Methods. As a method of compounding polyamic acid (1) and nano-silicon dioxide particles using organosilicon sol, it is also possible to synthesize polyamic acid (1) and then combine the synthesized polyamic acid (1) with The method of mixing organosilicon sol, but in order to disperse nano-silica particles in polyamic acid (1) to a higher degree, it is preferable to synthesize polyamic acid (1) in organosilicon sol.

In addition, in order to improve the interaction with the polyamic acid (1), the nano-silica particles can also be surface-treated with a surface treatment agent. As a surface treatment agent, well-known surface treatment agents, such as a silane coupling agent, can be used. As a silane coupling agent, the alkoxysilane compound etc. which have an amino group, a glycidyl group, etc. as a functional group are known, and can be selected suitably. In order to further enhance the interaction with the polyamic acid (1), the silane coupling agent is preferably an alkoxysilane containing an amino group. Examples of alkoxysilanes containing amino groups include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane silane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2 -Aminophenyltrimethoxysilane, 3-aminophenyltrimethoxysilane, etc. From the viewpoint of the stability of raw materials, it is preferable to use 3-aminopropyltriethoxysilane. The surface treatment method of nano-silica particles may, for example, be a method of stirring a mixture obtained by adding a silane coupling agent to a dispersion liquid (organic silicon sol) at an ambient temperature of 20°C or higher and 80°C or lower. The stirring time at this time is, for example, not less than 1 hour and not more than 10 hours. At this time, a catalyst or the like for promoting the reaction may be added.

With regard to making polyamic acid (1) and nano-silica particles compounded into nano-silica-polyamic acid complexes, relative to 100 parts by weight of polyamic acid (1), it is preferable In order to contain the nano-silica particle in the range of 1-30 weight part, it is more preferable to contain the nano-silica particle in the range of 1-20 weight part. If the content of nano-silicon dioxide particles is more than 1 weight part, the heat resistance of polyimide containing nano-silicon dioxide particles can be improved, and internal stress can be sufficiently reduced. If the content of nano-silicon dioxide particles is 30 parts by weight The adverse effect on the mechanical properties of polyimide containing nano silicon dioxide particles can be suppressed.

Moreover, in order to express the appropriate adhesiveness with a support, the polyamic acid composition of this embodiment can contain a silane coupling agent. The type of silane coupling agent can use a well-known silane coupling agent without particular limitation, From the viewpoint of the reactivity with polyamic acid (1), especially the compound containing an amino group is preferable.

The blending ratio of the silane coupling agent to 100 parts by weight of polyamic acid (1) is preferably from 0.01 to 0.50 parts by weight, more preferably from 0.01 to 0.10 parts by weight, and still more preferably from 0.01 parts by weight The above is 0.05 parts by weight or less. By making the blending ratio of the silane coupling agent 0.01 parts by weight or more, the peeling inhibitory effect on the support can be fully exhibited, and by making the blending ratio of the silane coupling agent 0.50 parts by weight or less, the polyamic acid (1 ) molecular weight decreased, so the embrittlement of the polyimide film can be suppressed.

The polyimide of the present embodiment is an imide of the above-mentioned polyamide acid (1). The polyimide of this embodiment can be obtained by a well-known method, and the manufacturing method is not specifically limited. Hereinafter, an example of the method of obtaining the polyimide of this embodiment by imidating polyamic acid (1) is demonstrated. The imidization is carried out by dehydrating and ring-closing polyamic acid (1). This dehydration ring closure can be performed by an azeotropic method using an azeotropic solvent, a thermal method, or a chemical method. In addition, the imidization from polyamic acid (1) to polyimide may take an arbitrary ratio of 1% to 100%. That is, polyamic acid (1) partially imidized can also be synthesized. Especially in the case of imidization by heating and raising the temperature, there is a ring-closing reaction from polyamic acid (1) to polyimide and the hydrolysis of polyamic acid (1) proceeds simultaneously, resulting in The molecular weight of polyimide may be lower than the molecular weight of polyamic acid (1), so from the viewpoint of improving mechanical properties, it is preferable to preform the polyimide film before forming the following polyimide film. Part of the polyamic acid (1) in the amino acid composition is imidized. In this specification, a partially imidized polyamide acid may also be described as "polyamide acid".

The dehydration and ring closure of the polyamic acid (1) can be carried out by heating the polyamic acid (1). The method of heating polyamic acid (1) is not particularly limited, for example, as long as it is coated on a support such as a glass substrate, a metal plate, or a PET film (polyethylene terephthalate film), the above-mentioned method of this embodiment After the polyamic acid composition, what is necessary is just to heat-treat polyamic acid (1) at the temperature in the range of 40-500 degreeC. According to this method, the present embodiment having a support and a polyimide film arranged on the support (specifically, a polyimide film containing an imide of polyamic acid (1)) was obtained. The layered body of the method. Alternatively, the polyamic acid composition can also be directly placed in a container that has been subjected to a release treatment such as coating with a fluorine-based resin, and the polyamic acid composition is heated and dried under reduced pressure. Carry out dehydration and ring closure of polyamide acid (1). Polyimide can be obtained by dehydration and ring closure of polyamic acid (1) by these methods. Furthermore, the heating time for each of the above treatments varies depending on the amount of polyamic acid composition to be dehydrated and ring-closed or the heating temperature, but generally speaking, it is preferably set at 1 minute or more after the treatment temperature reaches the highest temperature. 300 minutes or less.

The polyimide film of this embodiment (specifically, the polyimide film containing the imide of polyamic acid (1)) is colorless, transparent and has low yellowness, and can withstand TFT manufacturing steps. Glass transition temperature (heat resistance), so it is suitable for transparent substrate materials for flexible displays. The content of polyimide (specifically, the imide product of polyamide acid (1)) in the polyimide film of this embodiment is, for example, relative to the total amount of the polyimide film. 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and may be 100% by weight. Components other than polyimide in the polyimide film include, for example, the above-mentioned additives (more specifically, nano-silica particles, etc.).

The electronic device of this embodiment (more specifically, a flexible device, etc.) has the polyimide film of this embodiment, and the electronic element arrange|positioned directly or indirectly on this polyimide film. When the electronic device of this embodiment is used for a flexible display, first, an inorganic substrate such as glass is used as a support, and a polyimide film is formed thereon. Then, an electronic device is formed on the support by arranging (forming) electronic elements such as TFT on the polyimide film. The step of forming TFT is usually carried out in a wide temperature range of 150°C to 650°C, but in order to substantially achieve the desired performance, the oxide semiconductor layer or a-Si (amorphous silicon) will be formed at 300°C or higher layer, depending on the situation, a-Si or the like may be further crystallized by laser or the like.

At this time, when the thermal decomposition temperature of the polyimide film is low, outgassing may occur in the process of forming electronic components, and the outgassing may adhere to the oven in the form of sublimates and cause pollution in the oven. , or the inorganic film formed on the polyimide film (the following barrier film, etc.) or electronic components are peeled off, so the 1% weight loss temperature of polyimide is preferably 500°C or higher. The upper limit of the 1% weight loss temperature of polyimide should be as high as possible, for example, 600°C. The 1% weight reduction temperature can be adjusted, for example, by changing the content of residues having a rigid structure (more specifically, SFDA residues, BPDA residues, etc.). To describe in more detail, before forming the TFTs, an inorganic film such as a silicon oxide film (SiOx film) or a silicon nitride film (SiNx film) is formed on the polyimide film as a barrier film. At this time, in the case where the heat resistance of polyimide is low or the imidization is not complete, or when there are many residual solvents, the polyimide may be damaged during the high-temperature process after laminating the inorganic film. The situation where the polyimide and the inorganic film are peeled off due to the volatile components such as the decomposition gas of the amine. Therefore, ideally, in addition to the 1% weight loss temperature of polyimide being 500°C or higher, the weight loss rate when polyimide is held isothermally at a temperature in the range of 400°C to 450°C should not be reached. 1%.

In addition, according to the research of the present inventors, it has been found that polyimide obtained by using fluorine-containing monomers will generate corrosive gases such as hydrogen fluoride in the form of outgassing during high-temperature processes such as the manufacture of TFT devices. If corrosive gas is generated during the high-temperature process, the barrier film etc. laminated on the polyimide film may be corroded, and peeling may occur at the interface of the laminated body. In order to suppress the generation of corrosive gas, the fluorine atom content of the polyamic acid (1) is preferably less than 1% by weight, more preferably less than 0.5% by weight, still more preferably less than 0.1% by weight, and most preferably It is substantially 0% by weight (the polyamic acid (1) does not contain a residue derived from a fluorine-containing monomer).

As an indicator of the amount of hydrogen fluoride gas generated when the imide of polyamic acid (1) (polyimide in this embodiment) is used in a high-temperature process, detection intensity obtained by mass spectrometry can be exemplified. In detail, first, under the flow of helium gas, the above-mentioned polyimide was heated from an atmosphere temperature of 60° C. at a heating rate of 10° C./min. When the atmosphere temperature reached 470° C., the self- Gas generated from the above polyimide. Then, from the obtained mass spectrum (specifically, a mass spectrum showing the result of analyzing the components of the gas generated from the polyimide at an ambient temperature of 470°C), the gas presumed to be generated from hydrogen fluoride was read. The detection intensity of the peak at m/z=20 (hereinafter, sometimes described as "20 peak intensity"). There is a tendency that the greater the amount of hydrogen fluoride produced, the greater the intensity of the 20 peak. Furthermore, the flow rate of helium gas during analysis by the quadrupole mass spectrometer can be set in such a way that the gas generated from the above-mentioned polyimide can be analyzed in real time by the quadrupole mass spectrometer, for example, it is 50 mL/min or more and 150 The range of mL/min or less is preferably 80 mL/min or more and 120 mL/min or less.

Also, when the glass transition temperature (Tg) of polyimide is significantly lower than the process temperature, positional deviation may occur in the process of forming electronic components, so the Tg of polyimide is preferably 300°C Above, more preferably at least 350°C, still more preferably at least 400°C, still more preferably at least 420°C. The upper limit of Tg of polyimide should be as high as possible, for example, it is 470°C. Also, generally speaking, the thermal expansion coefficient of the glass substrate is smaller than that of the resin, so internal stress occurs between the glass substrate and the polyimide film. If the internal stress of a glass substrate used as a support or a laminate of an electronic component and a polyimide film is high, the laminate including the polyimide film will expand in the high-temperature TFT forming step, and then be cooled to It will shrink at room temperature, causing problems such as warping or breakage of the glass substrate, and peeling of the polyimide film from the glass substrate. Therefore, the internal stress between the polyimide film and the glass substrate is preferably 40 MPa or less, more preferably 35 MPa or less. The lower the lower limit of the internal stress, the better, it can also be 0 MPa. The method of measuring the internal stress is the same method as in the following examples or a method based thereon.

The polyimide of this embodiment is suitable as a material for display substrates such as TFT substrates and touch panel substrates. When polyimide is used for the above purposes, in many cases, after forming an electronic device on a support as described above (specifically, an electronic device obtained by forming electronic components on a polyimide film), A method for peeling a polyimide membrane from a support. Moreover, as a material of a support body, an alkali-free glass is used suitably. Hereinafter, an example of a method for producing a laminate of a polyimide film and a support will be described in detail.

First, the polyamic acid composition of the present embodiment is coated (cast) on a support to form a laminate including a coating film containing polyamic acid (1) and a coating film containing a support. Next, the laminated body including the coating film is heated at a temperature of, for example, 40°C to 200°C. The heating time at this time is, for example, not less than 3 minutes and not more than 120 minutes. Furthermore, multi-stage heating steps can also be provided, such as heating the laminate containing the coating film at a temperature of 50° C. for 30 minutes, and then heating at a temperature of 100° C. for 30 minutes. Next, in order to accelerate imidization of the polyamic acid (1) in the coating film, the laminate including the coating film is heated, for example, at a maximum temperature of 200°C to 500°C. The heating time at this time (heating time at the highest temperature) is, for example, not less than 1 minute and not more than 300 minutes. At this time, it is preferable to gradually raise the temperature from a low temperature to the highest temperature. The rate of temperature increase is preferably from 2°C/min to 10°C/min, more preferably from 4°C/min to 10°C/min. In addition, the maximum temperature is preferably in the range of not less than 250°C and not more than 450°C. When the highest temperature is 250°C or higher, imidization proceeds sufficiently, and when the highest temperature is 450°C or lower, thermal deterioration or coloring of polyimide can be suppressed. Moreover, you may hold|maintain at arbitrary temperature for arbitrary time until reaching a maximum temperature. The imidization reaction can be carried out under air, under reduced pressure, or in an inert gas such as nitrogen. In order to show higher transparency, it is preferably carried out under reduced pressure or in an inert gas such as nitrogen. In addition, as a heating device, known devices such as a hot air oven, an infrared oven, a vacuum oven, a non-oxidizing oven, and a hot plate can be used. Through these steps, the polyamic acid (1) in the coating film is imidized, and a support and a polyimide film (a film containing an imidized product of polyamic acid (1)) can be obtained. The laminated body (ie, the laminated body of this embodiment).

As a method of peeling the polyimide film from the obtained laminate of the support and the polyimide film, a known method can be used. For example, it can be peeled off by hand, or it can be peeled off using a mechanical device such as a driving roller or a robot. Furthermore, a method of providing a release layer between the support and the polyimide film can also be used; or by forming a silicon oxide film on a substrate with a plurality of grooves, the polyimide film can be formed using the silicon oxide film as the base layer. The amine film is a method in which the etching solution of silicon oxide is infiltrated between the substrate and the silicon oxide film, and the polyimide film is peeled off. Moreover, the method of separating a polyimide film by irradiating laser light can also be used.

The transparency of the polyimide film can be evaluated by the total light transmittance (TT) according to JIS K7361-1:1997, and the haze according to JIS K7136-2000. When the polyimide film is used for applications requiring high transparency, the total light transmittance of the polyimide film is preferably at least 75%, more preferably at least 80%. Also, when the polyimide film is used in a situation requiring high transparency, the haze of the polyimide film is preferably 1.5% or less, more preferably 1.2% or less, and still more preferably less than 1.0%. Can also be 0%. In applications that require high transparency, the polyimide film is required to have a high transmittance in the full wavelength region, but the polyimide film tends to absorb light at the short wavelength side, and the film itself is colored yellow There are many cases. In order to use the polyimide film for applications requiring high transparency, it is preferable to reduce coloring of the polyimide film. Specifically, in order to use the polyimide film for applications requiring high transparency, the yellowness (YI) of the polyimide film is preferably 25 or less, more preferably 20 or less, and may be 0. YI can be measured in accordance with JIS K7373-2006. YI can be adjusted, for example, by changing the content of SFDA residues in polyamic acid (1). In this way, the polyimide film with reduced coloration and imparted transparency is suitable for use as a transparent substrate for glass replacement purposes, or as a substrate on which a sensor or camera module is provided on the back.

In addition, there are two types of light extraction methods for flexible displays: a top emission method that extracts light from the front side of a TFT, and a bottom emission method that extracts light from the back side of a TFT. In the top emission method, since the light is not blocked by the TFT, it is easy to increase the aperture ratio and obtain high-definition image quality. The bottom emission method has the characteristics of easy alignment of the TFT and the pixel electrode, and is easy to manufacture. . If the TFT is transparent, the aperture ratio can also be increased in the bottom emission method, so there is a tendency for large-scale displays to adopt the bottom emission method that is easy to manufacture. The polyimide film of this embodiment has low YI and excellent heat resistance, so it can be applied to any of the above-mentioned light extraction methods.

In addition, a batch-type device production in which a polyimide composition is coated on a support such as a glass substrate and heated to imidize to form an electronic component or the like, and the polyimide film is peeled off In the procedure, it is preferable to have excellent adhesion between the support and the polyimide membrane. The term "adhesiveness" here means adhesive strength. After forming electronic components and the like on the polyimide film on the support, in the production process of peeling the polyimide film with the electronic components and the like from the support, if the polyimide film and the support are in close contact With excellent performance, electronic components and the like can be formed or mounted more accurately. From the viewpoint of improving productivity, in the production process of arranging electronic components and the like on a support with a polyimide film interposed therebetween, the higher the peel strength between the support and the polyimide film, the better. Specifically, the aforementioned peel strength is preferably at least 0.05 N/cm, more preferably at least 0.1 N/cm.

In the above-mentioned manufacturing process, when peeling the polyimide film from the laminate of the support and the polyimide film, the polyimide film is often peeled off from the support by laser irradiation. . In this case, it is necessary to make the polyimide film absorb the laser light, so the cutoff wavelength of the polyimide film is required to be longer than the wavelength of the laser light used for stripping. XeCl excimer laser with a wavelength of 308 nm is mostly used for laser stripping, so the cut-off wavelength of the polyimide film is preferably above 312 nm, more preferably above 330 nm. On the other hand, if the cutoff wavelength is long, the polyimide film tends to be colored yellow, so the cutoff wavelength of the polyimide film is preferably below 390 nm. From the viewpoint of both transparency (low yellowness) and processability of laser peeling, the cutoff wavelength of the polyimide film is preferably not less than 320 nm and not more than 390 nm, more preferably not less than 330 nm and not more than 380 nm. In addition, the cutoff wavelength in this specification means the wavelength at which the transmittance measured by an ultraviolet-visible spectrophotometer becomes 0.1% or less.

The polyamic acid composition and polyimide of this embodiment can be directly used in the coating or molding process for making products or components, but can also be used for further coating of molded objects formed into a film materials for processing. In order to be used in the coating or molding process, the polyamic acid composition or polyimide can also be dissolved or dispersed in an organic solvent as needed, and further, a photocurable component, a thermosetting component, a non-polymerizable Adhesive resin and other components to prepare a composition comprising polyamide acid (1) or polyimide.

Various inorganic thin films such as metal oxide thin films and transparent electrodes can also be formed on the surface of the polyimide film of this embodiment. The film-forming method of these inorganic thin films is not particularly limited, and for example, PVD (Physical Vapor Deposition, physical vapor deposition) methods such as sputtering, vacuum evaporation, and ion plating, or CVD ( Chemical Vapor Deposition, chemical vapor deposition) method.

The polyimide film of this embodiment not only has heat resistance, low thermal expansion, and transparency, but also has less internal stress when forming a laminate with a glass substrate, and can ensure close contact with inorganic materials in high-temperature processes. Therefore, it is preferably used in fields and products that can exert these characteristics. For example, the polyimide film of this embodiment is preferably used in liquid crystal display devices, organic EL, electronic paper and other image display devices, printed matter, color filters, flexible displays, optical films, 3D displays, touch screens, etc. Control panels, transparent conductive film substrates, solar cells, etc., and further, it is better used as a substitute material for the parts currently using glass. In these applications, the thickness of the polyimide film is, for example, not less than 1 μm and not more than 200 μm, preferably not less than 5 μm and not more than 100 μm. The thickness of the polyimide film can be measured using a laser holo gauge.

In addition, the polyamic acid composition of the present embodiment is suitable for use in a batch-type device production process in which the polyamic acid composition is coated on a support, heated to imidize, and formed into an electronic device, etc. After that, the polyimide film was peeled off. Therefore, this embodiment also includes a method of manufacturing an electronic device, which includes coating a polyamic acid composition on a support, heating to imidize it, and the polyimide formed on the support The step of forming electronic components etc. on the film. Moreover, the manufacturing method of this electronic device may further include the step of peeling the polyimide film on which the electronic element etc. were formed from a support body. [Example]

Hereinafter, examples of the present invention will be described, but the scope of the present invention is not limited to the following examples.

＜Measurement method of physical properties＞ First, the method for measuring the physical properties of polyimide (polyimide film) will be described.

[Yellowness (YI)] For the polyimide film in each of the laminates obtained in the following Examples and Comparative Examples, the wavelength of 200 nm to 800 nm was measured using an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation "V-650") For the following light transmittance, the yellowness (YI) of the polyimide film was calculated according to the formula described in JIS K7373-2006.

[haze] For the polyimide film peeled off from each of the laminates obtained in the following Examples and Comparative Examples, an integrating sphere haze meter ("HM-150N" manufactured by Murakami Color Technology Laboratory Co., Ltd.) was used, and the JIS Haze is measured by the method described in K7136-2000. When the haze was less than 1.0%, it was evaluated as "excellent in transparency". On the other hand, when the haze was 1.0% or more, it was evaluated as "not good in transparency".

[internal stress] The following examples and comparative examples were coated with a spin coater on a glass substrate (material: non-alkali glass, thickness: 0.7 mm, size: 100 mm×100 mm) manufactured by Corning, whose warpage was measured in advance. Each polyamic acid composition prepared in the above was heated at 120°C for 30 minutes in the air, and then heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminated polyimide film with a thickness of 10 μm on a glass substrate body. In order to eliminate the influence of water absorption of the polyimide film, the laminate was dried at 120°C for 10 minutes, and then measured using a thin film stress measurement device ("FLX-2320-S" manufactured by KLA-Tencor) in a nitrogen atmosphere at a temperature of 25°C The warpage of the laminate below. Then, the internal stress generated between the glass substrate and the polyimide film was calculated using Stoney's formula based on the amount of warpage of the glass substrate before the polyimide film was formed and the amount of warpage of the laminate. When the internal stress was 40 MPa or less, it was evaluated as "capable of reducing internal stress". On the other hand, when the internal stress exceeded 40 MPa, it was evaluated as "the internal stress cannot be reduced".

[Glass transition temperature (Tg)] A polyimide film having a width of 3 mm and a length of 10 mm was used as a sample for Tg measurement from each laminate obtained in the following Examples and Comparative Examples. Using a thermal analysis device ("TMA/SS7100" manufactured by Hitachi High-Tech Science Co., Ltd.), a load of 29.8 mN was applied to the sample, and the temperature was raised from 20°C to 500°C at 10°C/min. ) to obtain the TMA curve. The temperature of the inflection point of the obtained TMA curve (the temperature corresponding to the peak in the differential curve of the TMA curve) was defined as the glass transition temperature (Tg). When Tg is 420 degreeC or more, it evaluated as "excellent in heat resistance." On the other hand, when Tg was less than 420 degreeC, it was evaluated as "unfavorable heat resistance".

[1% Weight Loss Temperature (TD1)] Each polyimide film obtained in the following examples and comparative examples (specifically, the polyimide film obtained by sampling from each laminate so that the weight becomes 10 mg) was used as a measurement sample, and a differential Thermal-thermogravimetric simultaneous measurement device ("TG/DTA7200" manufactured by Hitachi High-Tech Science Co., Ltd.), under nitrogen atmosphere, the temperature was raised from 25°C to 650°C at a rate of 20°C/min, and the temperature was measured at 150°C The sample weight is used as a reference, and the measurement temperature when the weight of the reference is reduced by 1% by weight is defined as the 1% weight reduction temperature (TD1).

[Analysis of gas generated from polyimide membrane] The gas generated from the polyimide membrane during heating was analyzed using an analysis device that combined a thermogravimetric measurement device ("STA449 F5" manufactured by NETZSCH Corporation) and a quadrupole mass spectrometer ("JMS-Q1500GC" manufactured by JEOL Ltd.) for analysis. Hereinafter, the analysis procedure will be described.

First, using perfluorotributylamine as a standard substance, the voltage of the quadrupole mass spectrometer was adjusted so that the detection intensity of the peak at m/z=69 became 800,000. Then, using the above-mentioned thermogravimetric measuring device, under the flow rate of 100 mL/min of helium gas flow, from the ambient temperature of 60°C, the temperature increase rate of 10°C/min was used to test the polyimides obtained in the following comparative examples Membranes (specifically, polyimide membranes obtained by sampling each laminate with a mass of 140 mg) were heated, and gas generated from the polyimide membranes was analyzed using the above-mentioned quadrupole mass spectrometer when the ambient temperature reached 470°C. . Furthermore, by using the analysis device described above to heat the polyimide membrane under the flow of helium gas, and the helium gas becomes the carrier gas, the gas generated from the polyimide membrane can be analyzed in real time by the quadrupole mass spectrometer. Then, from the mass spectrum obtained by analyzing the gas generated from the polyimide film when the ambient temperature reached 470° C. by the quadrupole mass spectrometer, the detection intensity of the peak at m/z=20 (20 peak intensity) was read. In addition, the said mass spectrum adjusted the reference line so that the peak intensity at the temperature of 60 degreeC might become 2000±100.

-11,9'-[9H]茀]-1,3,7,9-四酮 BPDA：3,3',4,4'-聯苯四羧酸二酐 BPAF：9,9-雙(3,4-二羧基苯基)茀二酐 6FDA：4,4'-(六氟亞異丙基)二鄰苯二甲酸酐 PDA：對苯二胺 4-BAAB：4-胺基苯甲酸4-胺基苯酯 DABA：4,4'-二胺基苯甲醯苯胺 DATA：N,N'-二(4-胺基苯基)對苯二甲醯胺 PAM-E：1,3-雙(3-胺基丙基)四甲基二矽氧烷 TFMB：2,2'-雙(三氟甲基)聯苯胺 DMI：1,2-二甲基咪唑 <Preparation of polyimide film> Next, the preparation method of the polyimide film (laminate) of an Example and a comparative example is demonstrated. In addition, hereinafter, compounds and reagents are described with the following abbreviations. In addition, the preparation of the polyamic acid composition used in the production of the polyimide film was all carried out under a nitrogen atmosphere. NMP: N-methyl-2-pyrrolidone SFDA: spiro[11H-difluoro[3,4-b:3',4'-i]𠮿

-11,9'-[9H] fennel]-1,3,7,9-tetraketone BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride BPAF: 9,9-bis(3 ,4-dicarboxyphenyl) stildianhydride 6FDA: 4,4'-(hexafluoroisopropylidene) diphthalic anhydride PDA: p-phenylenediamine 4-BAAB: 4-aminobenzoic acid 4- Aminophenyl ester DABA: 4,4'-diaminobenzylaniline DATA: N,N'-bis(4-aminophenyl)terephthalamide PAM-E: 1,3-bis( 3-aminopropyl)tetramethyldisiloxane TFMB: 2,2'-bis(trifluoromethyl)benzidine DMI: 1,2-dimethylimidazole

[Example 1] Into a 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring rod and a nitrogen gas introduction tube, 88.0 g of NMP was added as an organic solvent for polymerization. Next, while stirring the contents of the flask, 2.240 g of PDA was put into the flask and dissolved. Next, after adding 9.760 g of SFDA to the contents of the flask, the contents of the flask were stirred for 24 hours in an atmosphere having a temperature of 25° C., thereby obtaining a polyamide acid composition. The obtained polyamic acid composition was coated on a glass substrate (manufactured by Corning, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm×100 mm) using a spin coater, and the After heating at 120° C. for 30 minutes, it was heated at 430° C. for 30 minutes under a nitrogen atmosphere to obtain a laminate (laminate of Example 1) having a polyimide film with a thickness of 10 μm on a glass substrate.

[Example 2] Into a 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring rod and a nitrogen gas introduction tube, 88.0 g of NMP was added as an organic solvent for polymerization. Next, while stirring the contents of the flask, 2.240 g of PDA was put into the flask and dissolved. Next, after adding 9.760 g of SFDA to the contents of the flask, the contents of the flask were stirred for 24 hours in an atmosphere at a temperature of 25°C. Next, DMI was added to the contents of the flask to obtain a polyamic acid composition. The amount of DMI added was 1 part by weight with respect to 100 parts by weight of polyamic acid in the contents of the flask. The obtained polyamic acid composition was coated on a glass substrate (manufactured by Corning, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm×100 mm) using a spin coater, and the After heating at 120° C. for 30 minutes, it was heated at 430° C. for 30 minutes under a nitrogen atmosphere to obtain a laminate (laminate of Example 2) having a polyimide film with a thickness of 10 μm on a glass substrate.

[Examples 3-17 and Comparative Examples 1-8] Except that the acid dianhydride used and its feeding ratio, and the diamine used and its feeding ratio are set as shown in Table 1 and Table 2, by the same method as in Example 1, the implementation Laminates of Examples 3, 5, 6, 8, 10, 12, 13, 15 and 17 and Comparative Examples 1, 2, 3 and 5. Also, except that the acid dianhydride used and its feeding ratio, and the diamine used and its feeding ratio were set as shown in Table 1 and Table 2, by the same method as in Example 2, respectively The laminates of Examples 4, 7, 9, 11, 14 and 16 and Comparative Examples 4, 6, 7 and 8 were obtained. In addition, about any one of Examples 3-17 and Comparative Examples 1-8, the total substance amount of the acid dianhydride at the time of preparing a polyamic-acid composition is the same as that of Examples 1 and 2. Moreover, about any of Examples 3-17 and Comparative Examples 1-8, the total substance amount of the diamine at the time of preparing a polyamic-acid composition was the same as that of Examples 1 and 2.

In addition, in Table 1 and Table 2, "-" means that this component was not used. In addition, in Table 1 and Table 2, the value in the column of "acid dianhydride" is the content rate (unit: mol %) of each acid dianhydride relative to the total amount of acid dianhydride used. In Table 1 and Table 2, the value in the column of "diamine" is the content rate (unit: mol %) of each diamine relative to the total amount of diamine used. In Table 1 and Table 2, the value in the "DMI" column refers to the amount of DMI relative to 100 parts by weight of polyamic acid (unit: parts by weight). Also, for any one of Examples 1-17 and Comparative Examples 1-8, the molar fraction of each residue of polyamic acid in the prepared polyamic acid composition is equal to that of polyamic acid. The molar fractions of the monomers (diamine and tetracarboxylic dianhydride) used in the synthesis are consistent.

[Table 1] Acid dianhydride [mole%] Diamine [mol%] DMI [parts by weight] SFDA BPDA BPAF 6FDA PDA 4-BAAB DABA DATA PAM-E TFMB Example 1 100 - - - 100 - - - - - - Example 2 100 - - - 100 - - - - - 1 Example 3 100 - - - - 100 - - - - - Example 4 100 - - - - 100 - - - - 1 Example 5 100 - - - - - 100 - - - - Example 6 50 50 - - 100 - - - - - - Example 7 50 50 - - 100 - - - - - 1 Example 8 30 70 - - 100 - - - - - - Example 9 30 70 - - 100 - - - - - 1 Example 10 30 70 - - - 100 - - - - - Example 11 30 70 - - - 100 - - - - 1 Example 12 15 85 - - 100 - - - - - - Example 13 15 85 - - 99.8 - - - 0.2 - - Example 14 15 85 - - 100 - - - - - 1 Example 15 10 90 - - - 100 - - - - - Example 16 10 90 - - - 100 - - - - 1 Example 17 100 - - - - - - 100 - - -

[Table 2] Acid dianhydride [mole%] Diamine [mol%] DMI [parts by weight] SFDA BPDA BPAF 6FDA PDA 4-BAAB DABA DATA PAM-E TFMB Comparative example 1 100 - - - - - - - - 100 - Comparative example 2 50 20 - 30 - - - - - 100 - Comparative example 3 - 85 15 - 100 - - - - - - Comparative example 4 - 85 15 - 100 - - - - - 1 Comparative Example 5 - 70 30 - - 100 - - - - - Comparative example 6 - - 100 - 100 - - - - - 1 Comparative Example 7 - - 100 - - 100 - - - - 1 Comparative Example 8 - - 100 - - - 100 - - - 1

＜Measurement results of physical properties＞ Table 3 shows the measurement results of physical properties for each of Examples 1-17 and Comparative Examples 1-8. In addition, in Table 3, "-" means that measurement was not performed. In addition, in Table 3, "fluorine atom content rate" is the calculated value calculated by the said formula.

[table 3] Internal stress [MPa] YI Haze[%] Tg [℃] TD1 [℃] 20 peak intensity Fluorine atom content [% by weight] Example 1 30 15 0.6 >450 515 - 0 Example 2 twenty four 10 0.3 >450 517 - 0 Example 3 40 9 0.2 437 505 - 0 Example 4 35 5 0.2 440 504 - 0 Example 5 25 20 0.6 430 500 - 0 Example 6 32 18 0.2 >450 564 - 0 Example 7 twenty two 14 0.2 >450 564 - 0 Example 8 11 18 0.3 >450 570 - 0 Example 9 7 15 0.2 >450 570 - 0 Example 10 1 12 0.3 445 516 - 0 Example 11 3 10 0.4 442 517 - 0 Example 12 6 19 0.4 438 571 - 0 Example 13 7 18 0.3 436 571 - 0 Example 14 7 16 0.3 440 570 - 0 Example 15 1 14 0.5 >450 535 - 0 Example 16 6 12 0.4 >450 534 - 0 Example 17 4 17 0.5 >450 495 - 0 Comparative example 1 60 5 0.3 >450 510 73,400 14.3 Comparative example 2 47 3 0.2 >450 504 112,100 19.8 Comparative example 3 15 18 0.3 400 560 - 0 Comparative example 4 20 16 0.4 404 561 - 0 Comparative Example 5 28 12 0.4 415 517 - 0 Comparative Example 6 50 5 0.2 445 504 - 0 Comparative Example 7 60 8 0.7 442 495 - 0 Comparative Example 8 45 10 0.4 430 491 - 0

The polyamic acid in the polyamic acid composition prepared in Examples 1-17 contains structural unit (1), and the content rate of a fluorine atom is 5 weight% or less. As shown in Table 3, in Examples 1 to 17, the internal stress was 40 MPa or less. Therefore, the polyimides obtained in Examples 1-17 can reduce internal stress. In Examples 1 to 17, the haze was less than 1.0%. Therefore, the polyimides obtained in Examples 1 to 17 were excellent in transparency. In Examples 1-17, Tg was 420 degreeC or more. Therefore, the polyimides obtained in Examples 1 to 17 were excellent in heat resistance.

The fluorine atom content of the polyamic acid in the polyamic acid compositions prepared in Comparative Examples 1 and 2 exceeded 5% by weight. The polyamic acid in the polyamic acid composition prepared in Comparative Examples 3-8 does not contain the structural unit (1). As shown in Table 3, in Comparative Examples 1, 2, and 6 to 8, the internal stress exceeded 40 MPa. Therefore, the polyimides obtained in Comparative Examples 1, 2, and 6-8 could not reduce internal stress. In Comparative Examples 3 to 5, Tg did not reach 420°C. Therefore, the heat resistance of the polyimides obtained in Comparative Examples 3-5 was not good.

The above results show that the polyimide obtained from the polyamic acid composition of the present invention reduces internal stress and has excellent transparency and heat resistance.

Claims (17)

A kind of polyamic acid, it comprises the structural unit represented by following general formula (1), and fluorine atom content rate is 5% by weight or less; [Chemical 1]

(In the above general formula (1), R ¹ and R ² each independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, and X ¹ represents a divalent organic group). Such as the polyamic acid of claim 1, wherein in the above general formula (1), R ¹ and R ² both represent hydrogen atoms. Such as the polyamic acid of claim 1, wherein in the above-mentioned general formula (1), ^X is selected from the divalent organic group represented by the following chemical formula (2-1), and the following general formula (2-2) More than one of the group formed by the represented divalent organic groups; [Chem. 2]

(In the above general formula (2-2), ^Y1 is selected from the divalent organic group represented by the following chemical formula (3-1), the divalent organic group represented by the following chemical formula (3-2), the following The divalent organic group represented by the chemical formula (3-3), the divalent organic group represented by the following chemical formula (3-4), the divalent organic group represented by the following chemical formula (3-5), and the following chemical formula (3-6) One or more of the group consisting of divalent organic radicals) [Chemical 3]

. As the polyamic acid of claim 1, it further comprises the structural unit represented by the following general formula (4); [Chemical 4]

(In the above general formula (4), R ³ and R ⁴ independently represent a hydrogen atom, a monovalent aliphatic group or a monovalent aromatic group, X ² represents a divalent organic group, Y ² is selected from the following chemical formula ( The tetravalent organic group represented by 5-1), the tetravalent organic group represented by the following chemical formula (5-2), the tetravalent organic group represented by the following chemical formula (5-3), and the following chemical formula (5 -4) More than one of the group consisting of tetravalent organic groups represented) [Chemical 5]

. The polyamic acid as claimed in claim 1, wherein the content of fluorine atoms is less than 1% by weight. A polyamic acid composition, which contains the polyamic acid as claimed in claim 1, and an organic solvent. The polyamic acid composition according to claim 6, further comprising an imidization accelerator. The polyamic acid composition according to claim 7, wherein the amount of the imidization accelerator is 10 parts by weight or less relative to 100 parts by weight of the polyamic acid. A polyimide, which is the imide compound of polyamide acid as claimed in claim 1. For example, the polyimide of claim 9 has a 1% weight loss temperature of 500°C or higher. For example, the polyimide of claim 9 has a glass transition temperature above 420°C. A polyimide film comprising the polyimide according to claim 9. As the polyimide film of claim 12, its yellowness is 25 or less. A laminate comprising a support and the polyimide film according to claim 12. The laminate according to claim 14, wherein the above-mentioned support is a glass substrate, The internal stress between the polyimide film and the glass substrate is 40 MPa or less. A method for manufacturing a laminate, which is a method for manufacturing a laminate having a support and a polyimide film, By coating the polyamic acid composition as claimed in claim 6 on a support to form a coating film comprising the above-mentioned polyamic acid, heating the above-mentioned coating film to animate the above-mentioned polyamic acid imidization. An electronic device, which has the polyimide film as claimed in claim 12, and the electronic components disposed on the polyimide film.