WO2023276864A1

WO2023276864A1 - Silsesquioxane compound and method for producing same

Info

Publication number: WO2023276864A1
Application number: PCT/JP2022/025227
Authority: WO
Inventors: 正幸横山; 哲雄奥山; 郷司前田; 洋行涌井; 直樹渡辺; 公洋松川; 建介中
Original assignee: 東洋紡株式会社; 国立大学法人京都工芸繊維大学
Priority date: 2021-06-29
Filing date: 2022-06-24
Publication date: 2023-01-05
Also published as: JPWO2023276864A1

Abstract

Provided is a silsesquioxane compound having a dicarboxylic anhydride group, the silsesquioxane compound being produced by reacting a thiol group in a condensation product B, which is a product of the condensation of a thiol-group-containing trialkoxysilane compound a1 represented by the general formula: R1Si(OR2)3 (wherein R1 represents an organic group having such a structure that at least one hydrogen atom in an aliphatic hydrocarbon group having 1 to 8 carbon atoms or the like is substituted by a thiol group; and R2's independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms or the like) with a trialkoxysilane compound a2 having no thiol group, with a reactive group comprising a vinyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group or an acid chloride group in a dicarboxylic anhydride C having the reactive group.

Description

Silsesquioxane compound and method for producing the same

The present invention relates to a novel silsesquioxane compound having a dicarboxylic anhydride group and a method for producing the same, and is useful as a raw material for producing polyimide films.

　Polyimide film has excellent heat resistance and good mechanical properties, and is widely used in the electrical and electronic fields as a flexible material. However, since a general polyimide film is colored yellowish brown, it cannot be applied to parts such as display devices that require light transmission.

On the other hand, display devices are becoming thinner and lighter, and there is a demand for greater flexibility. Therefore, attempts are being made to replace the substrate material from the glass substrate with a flexible polymer film substrate. However, the colored polyimide film cannot be used as a substrate material for a liquid crystal display that displays images by turning light transmission on and off. , the rear side of a reflective display system or a self-luminous display device.

Against this background, the development of colorless and transparent polyimide films is underway. When polyimide film is used as a flexible electronic circuit board, in addition to colorless transparency, low linear expansion coefficient (CTE) and low retardation (Rth), it is necessary to maintain mechanical strength under bending resistance and high temperature conditions during circuit formation. Therefore, high elastic modulus, mechanical strength, and high glass transition temperature (Tg) are required.

As a representative example, there are attempts to develop colorless and transparent polyimide films using fluorinated polyimide resins, semi-alicyclic or fully alicyclic polyimide resins, etc. (Patent Documents 1 to 3). These films are less colored and have transparency, but their mechanical strength is not as high as that of colored polyimide films. Colorlessness and transparency cannot always be maintained due to thermal decomposition or oxidation reaction.

From this point of view, a method of heat treatment while blowing a gas with a specified oxygen content has been proposed (Patent Document 4), but the production cost is high in an environment where the oxygen concentration is less than 18%, and industrial production is not possible. Extremely difficult.

In addition, as a means of further improving the properties of organic materials, composites of organic and inorganic materials are used to impart the properties of inorganic materials, such as high heat resistance, chemical resistance, and high surface hardness. There are organic-inorganic hybridization techniques. For example, it is known that CTE, Rth, and Tg can be improved while maintaining transparency by combining transparent polyimide and silica nanoparticles. However, there is a problem that as the amount of silica nanoparticles mixed increases, the film becomes more rigid and brittle, resulting in a decrease in mechanical strength.

On the other hand, silsesquioxane represented by RSiO _3/2 can easily provide an organic-inorganic hybrid cured product by giving R a substituent that can react with an organic material. (For example, Patent Document 5). Attempts have been made to improve heat resistance and workability by combining flexible silsesquioxane with polyimide. It is known that the charge transfer interaction between the imide portion of polyimide and silsesquioxane increases the thermal decomposition temperature (Non-Patent Document 1).

JP-A-11-106508 Japanese Patent Application Laid-Open No. 2002-146021 JP-A-2002-348374 WO2008/146637 Japanese Patent No. 3653976

However, since the flexible silsesquioxane structure reduces the rigidity of the polyimide, silsesquioxane composite polyimides usually exhibit relatively low elastic modulus and low Tg (Non-Patent Document 2). .

As described above, it is extremely difficult to produce a colorless and transparent polyimide film that has a low linear expansion coefficient, high heat resistance, and high mechanical strength. Semi-alicyclic or fully alicyclic polyimides are improved in colorless transparency by increasing the monomer component having an alicyclic structure, but the mechanical strength is lowered and production as a film becomes difficult. On the other hand, if an aromatic monomer is introduced, the toughness is increased and the mechanical properties of the film are improved, but the film tends to be colored and the colorless transparency is lowered. By introducing a filler (inorganic component) with a refractive index close to that of the resin component, heat resistance and colorless transparency are improved, and the linear expansion coefficient is lowered, improving workability, but the physical properties of the resin become hard and brittle. Mechanical properties are degraded.

Therefore, practical properties such as heat resistance, mechanical properties, and colorlessness (transparency or whiteness) are in a trade-off relationship. The emergence of a method to do so has been desired.

Therefore, an object of the present invention is to provide a novel silsesquioxane compound and a method for producing the same, which are useful as a raw material for producing a polyimide film having improved toughness while maintaining other main properties. That's what it is.

As a result of intensive research to solve the above problems, the present inventors found that the above objects can be achieved by a novel silsesquioxane compound in which a dicarboxylic anhydride group is introduced by reaction with a thiol group. was completed.

That is, the present invention includes the following contents.

[1] A silsesquioxane compound having a dicarboxylic anhydride group,
thiol group-containing trialkoxysilanes a1 represented by the general formula: R ¹ Si(OR ² ) ₃ ;
(Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R ² is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
trialkoxysilanes a2 having no thiol group;
a thiol group of the condensate B of
said reactive group of dicarboxylic anhydride C having at least one reactive group selected from vinyl group, alkenyl group, cycloalkenyl group, alkynyl group, and acid chloride group;
A silsesquioxane compound formed by the reaction of

[2] A silsesquioxane compound having a dicarboxylic anhydride group, which has structural units represented by the following general formulas (1) and (2).

(In the formula, Q ¹ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and Q ² is a single bond, a hydrocarbon group having 1 to 8 carbon atoms, an organic group in which one or more carbon atoms of the hydrocarbon group having 1 to 8 carbon atoms are substituted with oxygen, or a carbonyl group, and X is carbon- a carbon bond, or an aliphatic ring having 4 to 10 carbon atoms, an aromatic ring having 6 to 10 carbon atoms, or a heterocyclic ring in which some of the carbon atoms constituting these are substituted with oxygen or sulfur; One or more of the hydrogens bonded to may be substituted with a hydrocarbon group, and 1.0 ≤ m ≤ 2.0 and 1.4 ≤ n ≤ 1.6.)

(Wherein, Q ³ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and 1.4 ≤ n ≤ 1.6.)
[3] The molar ratio of the trialkoxysilanes a2 ([moles of a2]/[moles of a1+moles of a2]), or the molar ratio of the structural units represented by the general formula (2) ([structural The silsesquioxane compound according to [1] or [2], wherein unit (2)]/[structural unit (1)+structural unit (2)]) is 0.1 or more and 0.7 or less.

[4] The silsesquioxane compound according to [1] or [3], wherein the dicarboxylic anhydride C is a compound represented by a chemical formula selected from the following.

(Wherein, Rx represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
[5] A method for producing a silsesquioxane compound having a dicarboxylic anhydride group, comprising the following steps in order.

thiol group-containing trialkoxysilanes a1 represented by the general formula: R ¹ Si(OR ² ) ₃ ;
(Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R ² is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
A first step of hydrolyzing a trialkoxysilane a2 having no thiol group and water using an acidic catalyst to obtain a reaction mixture x;
a second step of removing the acidic catalyst from the reaction mixture x to obtain a reaction mixture y;
A third step of obtaining a condensate B having a thiol group by mixing and condensing a polar solvent containing a basic catalyst and the reaction mixture y, and the condensate B, a vinyl group, an alkenyl group, a cycloalkenyl group, A fourth step of reacting with a dicarboxylic anhydride C having at least one reactive group selected from an alkynyl group and an acid chloride group.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a novel silsesquioxane compound and a method for producing the same, which are useful as a raw material for producing a polyimide film having improved toughness while maintaining other main properties. .

1 is a ¹ H NMR (CDCl ₃ ) spectrum of SQ109 (PGMEA solution) used in Example 1. FIG. FIG. 1 shows a ¹ H NMR (CDCl ₃ ) spectrum of PGMEA; Note that δ=2.2 is a peak derived from acetone for washing instruments. 1 is a ¹ H NMR (CDCl ₃ ) spectrum of norbornenic anhydride used in Example 1. FIG. Note that δ=2.2 is a peak derived from acetone for washing instruments. 1 is a ¹ H NMR (CDCl ₃ ) spectrum of a reaction mixture after reaction in Example 1. FIG. 1 is a ¹ H NMR (CDCl ₃ ) spectrum of silsesquioxane SQ2 having an acid anhydride group obtained in Example 2. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ3 having an acid anhydride group obtained in Example 3. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ4 having an acid anhydride group obtained in Example 4. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ5 having an acid anhydride group obtained in Example 5. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ6 having an acid anhydride group obtained in Example 6. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ7 having an acid anhydride group obtained in Example 7. FIG. 1 is a ¹ H NMR (DMSO-d ₆ ) spectrum of silsesquioxane SQ8 having an acid anhydride group obtained in Example 8. FIG.

Although the present invention will be described in detail below, these are aspects of the present invention, and the present invention is not limited to these contents.

<Silsesquioxane compound A having a dicarboxylic anhydride group>
The novel silsesquioxane compound A is a silsesquioxane compound having a dicarboxylic anhydride group (hereinafter sometimes simply referred to as an "acid anhydride group") and a thiol group-containing silsesquioxane compound. a thiol group of condensate B and said reactive group of dicarboxylic anhydride C having at least one reactive group selected from vinyl groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, and acid chloride groups; is a silsesquioxane compound formed by the reaction of

The condensate B is a thiol group-containing trialkoxysilane a1 represented by the general formula: R ¹ Si(OR ² ) ₃ ,
(Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R ² is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
It is a condensate B of trialkoxysilanes a2 having no thiol group.

Here, the thiol group-containing trialkoxysilanes a1 and the trialkoxysilanes a2 both have three reactive alkoxy groups, so the structure of the resulting product has a three-dimensionally complicated structure. , it is not realistic to specify the entire structure by a chemical formula. For this reason, the product invention was specified in the form of manufacturing method limitation (product-by-process).

However, it is possible to partially specify the structure as two repeating units. That is, the novel silsesquioxane compound A preferably has structural units represented by the following general formulas (1) and (2).

(Wherein, Q ³ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and 1.4 ≤ n ≤ 1.6.)
In another aspect, the novel silsesquioxane compound A is not limited to the product specified by the above manufacturing method limitation, and as two repeating units, structural units represented by the following general formulas (1) and (2) can be identified as having

The novel silsesquioxane compound A can be suitably produced, for example, by the production method of the present invention. That is, the production method of the present invention is a method for producing a silsesquioxane compound having a dicarboxylic anhydride group, comprising the following steps in order.

In addition, a commercially available thiol group-containing silsesquioxane compound (condensate B) and at least one reactive group selected from a vinyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, and an acid chloride group It can also be obtained by reacting with a dicarboxylic anhydride C having

<Condensate B (thiol group-containing silsesquioxane compound)>
Condensate B is a condensate of thiol group-containing trialkoxysilanes a1 and trialkoxysilanes a2 having no thiol group. As the condensate B, for example, an organic/inorganic hybrid resin Compoceran SQ (product name: SQ107 or SQ109, Arakawa Chemical Industries, Ltd.) can be used. Alternatively, the condensate B synthesized by a method including the above 1st to 3rd steps can be used.

<First step>
In the first step, thiol group-containing trialkoxysilanes a1 represented by the general formula: R ¹ Si(OR ² ) ₃ , trialkoxysilanes a2 having no thiol group, and water are combined with an acidic catalyst. It is a step of obtaining a reaction mixture x by hydrolyzing with

(Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R ² is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
Here, the limitation on the number of carbon atoms such as "1 to 8 carbon atoms" means the number of carbon atoms in the entire organic group including substituents.
More specifically, in the above general formula, R ¹ has at least one thiol group and is a hydrocarbon group having 1 to 8 carbon atoms having a straight chain, branched chain, or aliphatic ring, or a hydrocarbon group. represents an aromatic hydrocarbon group having 6 to 8 carbon atoms which may be present. R ¹ is preferably a linear hydrocarbon group from the viewpoint of imparting flexibility to the polymer chain, and preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group from the viewpoint of enhancing heat resistance.

R ² independently of each other may have a hydrogen atom, a linear or branched chain, or an aliphatic ring-containing hydrocarbon group having 1 to 8 carbon atoms, or a hydrocarbon group; Represents 6-8 aromatic hydrocarbon groups. From the viewpoint of hydrolysis reaction reactivity, R ² is preferably an alkyl group having 1 to 4 carbon atoms. A methyl group or an ethyl group is particularly preferred.

Specific examples of the thiol group-containing trialkoxysilanes a1 (hereinafter referred to as component (a1)) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercapto propyltributoxysilane, 1,4-dimercapto-2-(trimethoxysilyl)butane, 1,4-dimercapto-2-(triethoxysilyl)butane, 1,4-dimercapto-2-(tripropoxysilyl)butane, 1,4-dimercapto-2-(tributoxysilyl)butane, 2-mercaptomethyl-3-mercaptopropyltrimethoxysilane, 2-mercaptomethyl-3-mercaptopropyltriethoxysilane, 2-mercaptomethyl-3-mercaptopropyl tripropoxysilane, 2-mercaptomethyl-3-mercaptopropyltributoxysilane, 1,2-dimercaptoethyltrimethoxysilane, 1,2-dimercaptoethyltriethoxysilane, 1,2-dimercaptoethyltripropoxysilane, 1,2-dimercaptoethyltributoxysilane and the like can be mentioned, and any one of the exemplified compounds can be used alone or in combination as appropriate. Among the exemplified compounds, 3-mercaptopropyltrimethoxysilane is particularly preferred because of its high hydrolytic reactivity and easy availability.

Examples of trialkoxysilanes a2 having no thiol group (hereinafter referred to as component (a2)) include compounds represented by the general formula: R ³ Si(OR ² ) ₃ . (In the formula, R ³ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and R ² is , each independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. )
More specifically, R ³ is a hydrocarbon group having 1 to 8 carbon atoms having a linear or branched chain or an aliphatic ring, or a hydrocarbon group having 6 to 8 carbon atoms which may have a hydrocarbon group. represents an aromatic hydrocarbon group. R ² is as described for component (a1), and may be the same as or different from R ² in component (a1).

Specific examples of component (a2) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane. Component (a2) can be used either singly or in combination of two or more. By using these, the amount of thiol groups can be adjusted, so that the degree of cross-linking of the finally obtained polyimide can be adjusted and the proportion of the inorganic component in the polyimide can be increased.

The molar ratio of the trialkoxysilanes a2 in the alkoxysilanes ([moles of a2]/[moles of a1+moles of a2]) is preferably 0.1 or more and 0.7 or less. It is more preferably 2 or more and 0.7 or less. The larger the molar ratio, the smaller the amount of thiol groups contained per molecule, and the smaller the molar ratio, the larger the amount of thiol groups. Within this range, the resulting polyimide chain is appropriately crosslinked, and the effect of improving physical properties is sufficient.

Condensate B, which is a thiol group-containing silsesquioxane, can be obtained by using component (a1) and component (a2), hydrolyzing them, and then condensing them. In the first step, the alkoxy groups contained in the component (a1) and the component (a2) are converted into silanol groups by the hydrolysis reaction, and alcohol is produced as a by-product.

The amount of water required for the hydrolysis reaction is expressed as a molar ratio ([number of moles of water used for hydrolysis reaction]/[total number of moles of each alkoxy group contained in component (a1) and component (a2)]). 0.4 to 10 are preferred. When this molar ratio is 0.4 or more and less than 0.5, some alkoxy groups will remain in the resulting thiol group-containing silsesquioxane, but adhesion to inorganic materials can be improved. Moreover, in the case of 0.5 to 10, substantially no alkoxy group remains in the thiol group-containing silsesquioxane to be obtained, and a thick film cured product can be easily produced.

In addition to the component (a1) and the component (a2), dialkoxysilanes and/or tetraalkoxysilanes may be further used within a range that does not impair the effects of the present invention (for example, 50 mol % or less). It is possible.

As the catalyst used for the hydrolysis reaction, any conventionally known acidic catalyst that can function as a hydrolysis catalyst can be used. However, since it is necessary to substantially remove the acid catalyst after the hydrolysis reaction, it is preferably one that can be easily removed. These include formic acid, which has a low boiling point and can be removed by vacuum, and solid acid catalysts, which can be easily removed by methods such as filtration.

Examples of solid acid catalysts include cation exchange resins, activated clay, and carbon-based solid acids. Among them, cation exchange resins are preferable because they have high catalytic activity and are easily available. As the cation exchange resin, a strong acid type cation exchange resin and a weak acid type cation exchange resin can be used. As strong acid type ion exchange resins, Diaion SK series, Diaion UBK series, Diaion PK series, Diaion HPK25/PCP series (all product names of Mitsubishi Chemical Corporation), Amberlite IR120B, Diaion IR124, Diaion 200CT, Diaion 252, Amberjet 1020, 1024, 1060, 1220, Amberlyst 15DRY, 15JWET, 16WET, 31WET, 35WET (all product names of Organo Co., Ltd.) as weakly acidic ion exchange resins , DIAION WK series, DIAION WK40 (both product names of Mitsubishi Chemical Corporation), Amberlite FPC3500, DIAION IRC76 (both product names of Organo Corporation), and the like. Although the type of ion-exchange resin to be used can be arbitrarily selected depending on the reaction rate, suppression of side reactions, etc., strongly acidic ion-exchange resins are particularly preferred from the viewpoint of reactivity.

The amount of the acid catalyst to be added is preferably 0.1 to 25 parts by mass, more preferably 1 to 10 parts by mass, with respect to 100 parts by mass in total of the components (a1) and (a2). When it is 25 parts by mass or less, it tends to be easy to remove in a later step, which tends to be economically advantageous. On the other hand, when the amount is 0.1 parts by mass or more, the reaction can proceed appropriately, and there is a tendency that the reaction time does not become too long.

The reaction temperature and time can be arbitrarily set according to the reactivity of component (a1) and component (a2), but are usually about 0 to 100°C, preferably about 20 to 60°C for about 1 minute to 2 hours. The hydrolysis reaction can be carried out in the presence or absence of a solvent, preferably without solvent. When a solvent is used, the type of solvent is not particularly limited, and one or more arbitrary solvents can be selected and used, but it is preferable to use the same solvent as used in the condensation reaction described below.

<Second step>
The second step is to remove the acidic catalyst from the reaction mixture x to obtain a reaction mixture y. That is, it is necessary to substantially remove the acid catalyst from the system after the hydrolysis reaction in the first step is completed. If not removed, the reaction does not proceed in the condensation reaction described later, the silanol group is not completely consumed, or the system gels due to an abnormal increase in the molecular weight. Oxane (condensate B) cannot be obtained.

The method for removing the acidic catalyst can be appropriately selected from various known methods depending on the catalyst used. For example, as described above, when formic acid is used, it can be easily removed by reducing pressure, and when a solid acid catalyst is used, it can be easily removed by a method such as filtration after completion of the condensation reaction.

In addition, after the hydrolysis reaction is completed and the acid catalyst is removed from the system, or at the same time as the removal of the acid catalyst, by-product alcohol and excess water may be removed by a method such as decompression. Further, by diluting with the solvent used for the condensation reaction after removal, it is possible to facilitate the addition of the hydrolyzate in the subsequent condensation reaction.

<Third step>
The third step is a step of obtaining a condensate B having a thiol group by mixing and condensing a polar solvent containing a basic catalyst and the reaction mixture y. In the condensation reaction, water is by-produced between the silanol groups, and alcohol is by-produced between the silanol groups and the alkoxy groups, forming siloxane bonds. A conventionally known basic catalyst capable of functioning as a dehydration condensation catalyst can be arbitrarily used in the condensation reaction.

The basic catalyst preferably has a high basicity, and specific examples thereof include alkali salts such as sodium hydroxide (NaOH), potassium hydroxide (KOH) and calcium hydroxide (Ca(OH) ₂ ); Organic amines such as 8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, tetramethylammonium hydroxide, tetrabutylammonium hydroxide and ammonium hydroxides such as Any one of the exemplified compounds can be used alone or in combination as appropriate. Among the exemplified compounds, tetramethylammonium hydroxide is particularly preferred because of its high catalytic activity and easy availability. In addition, when these basic catalysts are used as an aqueous solution, the hydrolysis reaction proceeds even in the condensation reaction step. , should be adjusted accordingly.

The amount of the basic catalyst to be added is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, with respect to 100 parts by mass in total of component (a1) and component (a2). more preferred. If the amount of the basic catalyst added is 5 parts by mass or less, the cured product prepared using the obtained thiol group-containing silsesquioxane (condensate B) is difficult to color, and when removing the catalyst, it is removed. This tends to make the process of On the other hand, when the amount is 0.01 part by mass or more, the reaction can proceed appropriately, and there is a tendency that the reaction time does not become too long.

The reaction temperature can be arbitrarily set according to the reactivity of component (a1) and component (a2), but is usually about 40 to 150°C, preferably about 60 to 100°C. The condensation reaction is preferably carried out in the presence of a polar solvent, and from the viewpoint of the stability of the obtained silsesquioxane compound A and its copolymer amic acid solution and the quality of the resulting film, a solvent such as toluene is used. It is more preferable not to contain a non-polar solvent.

As the polar solvent, a polar solvent that exhibits compatibility with water is preferable, and glycol ethers are particularly preferable. Among glycol ethers, dialkyl glycol ether solvents are particularly preferred. Examples of dialkyl glycol ether-based solvents compatible with water include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether. Glycol ether acetate solvents such as propylene glycol monomethyl ether acetate (PGMEA), dipropylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate can also be used.

The condensation reaction can also be carried out by setting the reaction temperature to a polar solvent containing a dehydration condensation catalyst and sequentially adding a solution containing the hydrolyzate obtained in the hydrolysis reaction. The method of addition can be appropriately selected from various known methods. The time required for addition can be arbitrarily set depending on the reactivity of component (a1) and component (a2), but is usually about 30 minutes to 12 hours.

When carrying out the condensation reaction by the above method, it is preferable to carry out the reaction until there are substantially no unreacted silanol groups. When unreacted silanol groups remain, storage stability of the obtained thiol group-containing silsesquioxane (condensate B) or composition containing the condensate B is lowered, and heat resistance is lowered, which is preferable. No.

In addition, the total molar ratio of unreacted alkoxy groups ([total number of moles of unreacted alkoxy groups]/[total number of moles of each alkoxy group contained in component (a1) and component (a2)]) is 0.5. It is preferable to proceed so that it becomes 2 or less, and it is more preferable to make it substantially 0. When this molar ratio is more than 0 and 0.2 or less, some alkoxy groups will remain in the resulting thiol group-containing silsesquioxane (condensate B), but adhesion to inorganic materials is preferable in terms of improvement. By setting the molar ratio to 0, substantially no alkoxy groups remain, making it easy to produce a thick film cured product, and the cage structure contained in the resulting thiol group-containing silsesquioxane (condensate B). is maximized, which is particularly preferable from the viewpoint of improving the heat resistance of the cured product. If it is not 0, the amount of random silsesquioxane contained in the obtained condensate B tends to increase, and the molecular weight (Mw) of the condensate B tends to increase.

The condensation reaction is preferably carried out by diluting with a solvent so that the total concentration of component (a1) and component (a2) is about 2 to 80% by mass, more preferably 15 to 75% by mass. It is preferable to use a solvent having a boiling point higher than that of water and alcohol produced by the condensation reaction, because these can be distilled off from the reaction system. A concentration of 2% by mass or more is preferable because the thiol group-containing silsesquioxane (condensate B) contained in the obtained curable composition is sufficient. When it is 80% by mass or less, it becomes difficult to gel during the reaction, and the resulting condensate B tends to have an appropriate molecular weight.

It is preferable to remove the used catalyst after completion of the condensation reaction because the stability of the thiol group-containing silsesquioxane (condensate B) and the polyimide containing the condensate B is improved. The removal method can be appropriately selected from various known methods according to the catalyst used. For example, when tetramethylammonium hydroxide is used, it can be removed by adsorption and removal with a cation exchange resin after completion of the condensation reaction.
<Fourth step>
In the fourth step, the condensate B and a dicarboxylic anhydride C having at least one reactive group selected from a vinyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, and an acid chloride group. This is the step of reacting.

A dicarboxylic anhydride having a functional group capable of reacting with a thiol group is used as the dicarboxylic anhydride C (hereinafter referred to as component (C)). For example, dicarboxylic acid anhydrides having vinyl groups, acryl groups, methacryl groups, allyl groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, or acid chloride groups can be used. More preferably, a dicarboxylic anhydride having a vinyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, or an acid chloride group can be used. In particular, the dicarboxylic anhydride C preferably has the following structure.

Among these, the following compounds and compounds having an acid chloride group are particularly preferred due to their high reactivity. In the case of using dicarboxylic anhydride C, which has low reactivity, it is difficult to proceed the reaction completely with only UV light, so it is preferable to use an oxidation catalyst such as oxygen or iron chloride together.

Among the dicarboxylic acid anhydrides C, phthalic anhydride compounds having an aromatic ring structure are desirable from the viewpoint of improving the heat resistance of the resulting polyimide and suppressing yellowing under high-temperature conditions. Maleic anhydride and cyclohexanedicarboxylic anhydride having a cyclic structure are desirable in terms of enhancing colorless transparency.

For the reaction between the thiol group-containing silsesquioxane (condensate B) and the dicarboxylic anhydride C, a thiol-ene reaction or a reaction between a thiol group and an acid chloride group can be used.

In the case of the thiol-ene reaction, it is known that the reaction mechanism differs depending on the type of carbon-carbon double bond and the presence or absence of a radical polymerization initiator. That is, when a compound having a vinyl group or an allyl group with low radical polymerizability is used as component (C), only the en-thiol reaction proceeds, and the thiol group in condensate B and component (C) Carbon-carbon double bonds react at approximately 1:1 (molar ratio) and are preferred. On the other hand, when a compound having a highly radically polymerizable acrylic group or methacrylic group is used as the component (C), the carbon-carbon double bond in the component (C) is particularly affected when a radical polymerization initiator is used in combination. The polymerization reaction also proceeds in parallel, and the thiol group in the condensate B and the carbon-carbon double bond in the component (C) react at a ratio of about 1: 1 to 100 (molar ratio), so the effect of the invention is You may not get enough. From the above point of view, when the component (C) having a low radically polymerizable vinyl group or allyl group is used, the molar ratio ([number of moles of thiol groups contained in condensate B]/[component (C) The number of moles of carbon-carbon double bonds contained in]) is preferably 0.9 to 2.5, more preferably 1.0. When this molar ratio is 0.9 or more, the carbon-carbon double bond is less likely to remain after UV curing, and the weather resistance tends to be improved. Moreover, when it is 2.5 or less, the crosslink density of the cured product becomes sufficient, and there is a tendency to improve the heat resistance.

As a thiol-ene reaction initiator, an ultraviolet light source, an organic material, an inorganic material, or oxygen can be used. As an ultraviolet light source, for example, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, or an ultraviolet LED can be used.

Usable initiators are not particularly limited, and conventionally known photo cationic initiators, photo radical initiators, oxidizing agents, etc. can be arbitrarily selected. Examples of photocationic initiators include sulfonium salts, iodonium salts, metallocene compounds, benzoin tosylate, etc., which are compounds that generate acid upon irradiation with ultraviolet rays. -6974, UVI-6990 (all trade names of Union Carbide Co., USA), Irgacure 264 (manufactured by BASF), CIT-1682 (manufactured by Nippon Soda Co., Ltd.), and the like. The amount of the cationic photopolymerization initiator to be used is usually about 10 parts by weight or less, preferably 1 to 5 parts by weight, per 100 parts by weight of the composition.

Examples of the photoradical initiator include Darocure 1173, Irgacure 651, Irgacure 184, Irgacure 907 (all trade names manufactured by BASF), benzophenone, and the like, preferably about 5 parts by weight or less per 100 parts by weight of the composition. is 0.1 to 2 parts by mass. Moreover, the reaction can be accelerated by adding an oxidizing agent such as iron oxide or iron chloride. However, for substrate film applications that require high heat resistance and transparency, it is desirable to use an ultraviolet light source or oxygen for the reaction without using a photoreaction initiator or photosensitizer.

In the case of a reaction between a thiol group and an acid chloride group, a dicarboxylic acid anhydride having an acid chloride group equivalent to or greater than the sum of the thiol group amount and the silanol group amount of the silsesquioxane (condensate B). addition is preferred. If the amount of the dicarboxylic anhydride having an acid chloride group added is small, the by-product hydrochloric acid acts as a catalyst, causing condensation between silanol groups, which tends to cause gelation. The greater the amount, the easier it is to reduce the harmful effects. In this case, unreacted acid chloride groups may be copolymerized with polyamic acid to form polyamidoimide.

In addition, in the case of the reaction between the thiol group and the acid chloride group, hydrochloric acid is generated as a by-product, so a base may be added as a pH adjuster. Organic bases, tertiary amines and inorganic bases can be used as bases. Examples of organic bases are N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2- Imidazolidinone, imidazole, N-methylcaprolactam, imidazole, N,N-dimethylaniline and N,N-diethylaniline. Examples of tertiary amines include pyridine, collidine, lutidine and triethylamine. Examples of inorganic bases include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate. However, for substrate film applications that require high heat resistance and transparency, it is desirable to use a volatile base for the reaction. By removing hydrochloric acid by adding a base or heating the solution, gelation due to excessive reaction of silsesquioxane can be suppressed.

The following are examples of solvents used for the reaction. Benzene, toluene, xylene, mesitylene, pentane, hexane, heptane, octane, nonane, decane, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N- Methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, imidazole, N-methylcaprolactam, dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, diethylsulfone, hexamethylsulfolamide, cresol, pheno xylenol, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraglyme, propylene glycol monomethyl ether acetate (PGMEA), dioxane, tetrahydrofuran, and gamma-butyrolactone. At least two of these may be mixed and used. In particular, considering the productivity and the optical properties of the film, it is preferable to use N,N-dimethylacetamide, N-methyl-2-pyrrolidone, or γ-butyrolactone as the main component of the organic solvent. In addition to these organic solvents, a poor solvent such as toluene or xylene may be used to the extent that the polyimide resin or its precursor does not precipitate.

The silsesquioxane compound A having an acid anhydride group obtained in the fourth step can be used as it is after the reaction. It can also be used as a powder.

<Structure of Silsesquioxane Compound A Having an Acid Anhydride Group>
The silsesquioxane compound A that can be obtained as described above preferably has structural units represented by the following general formulas (1) and (2). It is more preferred to have only the structural units represented.

(Wherein, Q ³ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and 1.4 ≤ n ≤ 1.6.)
More specifically, Q ¹ in general formula (1) may have a hydrocarbon group having 1 to 8 carbon atoms having a straight chain, a branched chain, or an aliphatic ring, or a hydrocarbon group, It represents an aromatic hydrocarbon group having 6 to 8 carbon atoms. ^Q1 is preferably a linear hydrocarbon group from the viewpoint of imparting flexibility to the polymer chain, and preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group from the viewpoint of enhancing heat resistance.

Specific examples of Q ¹ include a hydrocarbon group in which the Si atom and the S atom of the compound exemplified as the thiol group-containing trialkoxysilanes a1 are bonded, or an aromatic hydrocarbon group.

Q ² is a hydrocarbon group having 1 to 8 carbon atoms having a single bond, a straight chain, or a branched chain, an oxygen-containing hydrocarbon group in which one or more of the carbon atoms is substituted with oxygen, or a carbonyl group . ^Q2 is preferably a straight-chain hydrocarbon group from the viewpoint of imparting flexibility to the polymer chain, and is preferably a single bond, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group from the viewpoint of improving heat resistance.

X is a carbon-carbon bond, or an aliphatic ring having 4 to 10 carbon atoms, an aromatic ring having 6 to 10 carbon atoms, or a heterocyclic ring in which some of the carbon atoms constituting these are substituted with oxygen or sulfur It is a ring, and one or more of the hydrogen atoms attached thereto may be substituted with a hydrocarbon group. X is preferably a carbon-carbon bond from the viewpoint of imparting flexibility to the polymer chain, and preferably a single bond, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group from the viewpoint of improving heat resistance. In particular, when X is an aromatic hydrocarbon group, it is preferable from the viewpoint of being able to improve heat resistance and suppress discoloration under high temperature conditions.

Specific examples of ^Q2 and X include reactive residues of compounds exemplified as dicarboxylic anhydride C, excluding dicarboxylic anhydride groups. In addition, the following chemical formulas show examples in which X is a heterocyclic ring in which a part of carbon atoms constituting an aliphatic or aromatic ring is substituted with oxygen or sulfur.

m is 1.0≦m≦2.0, and m is preferably 1 from the viewpoint of small steric hindrance and high reactivity of the dicarboxylic anhydride group. When m is 1.0<m<2.0 (that is, other than an integer), a component (a1) having one thiol group and a component having two thiol groups are used in combination.

n is 1.4≦n≦1.6, and from the viewpoint of forming a more uniform three-dimensional structure, n is preferably 1.5. The reason why n is assumed to be other than 1.5 is to allow a small amount of not only trialkoxysilane but also dialkoxysilane and tetraalkoxysilane to be mixed in the raw material.

In addition, Q ³ in the general formula (2) may have a hydrocarbon group with 1 to 8 carbon atoms having a straight chain, a branched chain, or an aliphatic ring, or a hydrocarbon group with 6 carbon atoms. represents an aromatic hydrocarbon group of ∼8. ^Q3 is preferably a short-chain or branched-chain hydrocarbon group or an aromatic hydrocarbon group from the viewpoint of suppressing crystallization and improving heat resistance. Specific examples of ^Q3 include a hydrocarbon group or an aromatic hydrocarbon group that bonds to the Si atom of the compounds exemplified as the trialkoxysilanes a2.

In the silsesquioxane compound A having the structural units represented by the general formulas (1) and (2), the molar ratio of the structural units represented by the general formula (2) ([structural unit (2)]/[structure Unit (1)+Structural Unit (2)]) is preferably 0.1 or more and 0.7 or less, more preferably 0.2 or more and 0.7 or less. The larger the molar ratio, the smaller the amount of thioether groups or thioester groups contained per molecule, and the smaller the molar ratio, the larger the amount of thioether groups or thioester groups. Within this range, the resulting polyimide chain is appropriately crosslinked, and the effect of improving physical properties is sufficient.

The number of acid anhydride groups (number of functional groups) per molecule of the silsesquioxane compound A is preferably 2-10, more preferably 2.5-6. When the number of functional groups is within this range, the resulting polyimide chain is moderately crosslinked, so that the effect of improving physical properties is sufficient.

The molecular weight of the silsesquioxane compound A is preferably 400-5000, more preferably 600-3000. When the molecular weight is within this range, the resulting polyimide is less likely to become non-uniform, and a uniform crosslinked structure is likely to be obtained.

In the general formulas (1) and (2), it is easy to obtain those that are randomly bonded. can be a silsesquioxane compound of the type

<Use of silsesquioxane compound A having an acid anhydride group>
Since the silsesquioxane compound A has an acid anhydride group, it can be directly reacted with a compound having an amino group or a hydroxyl group, and since it produces a carboxyl group by reaction with water, it can be used with a wider variety of compounds. can be reacted.

In particular, a silsesquioxane compound having two or more acid anhydride groups serves as a monomer component of polyimide, and a silsesquioxane compound having more than two acid anhydride groups serves as a copolymerization component to form a crosslinked structure in polyimide. can be formed.

For polyimide, in general, there is a trade-off relationship between practical properties such as heat resistance and mechanical properties, and colorlessness (transparency or whiteness). In particular, toughness was improved while maintaining other properties. It would be desirable to have a method for making polyimide films.

By using the silsesquioxane compound A as a copolymerization component, it is possible to produce a polyimide film having improved toughness while maintaining other main properties. is particularly useful. A polyimide film can be obtained, for example, by including a step of synthesizing a polyamic acid solution, a step of forming a film from the polyamic acid solution, and a step of imidating the polyamic acid.

<Synthesis of polyamic acid solution>
Carboxylic acids and diamines can be used as the polyamic acid monomer component to be combined with the silsesquioxane compound A having an acid anhydride group.

The carboxylic acids are not particularly limited, and include alicyclic tetracarboxylic anhydrides and aromatic tetracarboxylic anhydrides, tricarboxylic acids, and dicarboxylic acids that are commonly used in polyimide synthesis, polyamideimide synthesis, and polyamide synthesis. can be used. Aromatics are preferred from the viewpoint of heat resistance, and alicyclics are preferred from the viewpoint of transparency. These may be used alone or in combination of two or more.

The alicyclic tetracarboxylic anhydrides used in the present invention include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, and 1,2,3,4-cyclohexane. Tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3′,4,4′-bicyclohexyltetracarboxylic acid, bicyclo[2,2,1]heptane-2,3,5,6 -tetracarboxylic acid, bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic acids, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, Decahydronaphthalene-2,3,6,7-tetracarboxylic acid, Decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid, Decahydro-1,4-ethano- 5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2″-norbornane-5,5″,6, 6''-tetracarboxylic acid (also known as "norbornane-2-spiro-2'-cyclopentanone-5'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid" ), methylnorbornane-2-spiro-α-cyclopentanone-α′-spiro-2″-(methylnorbornane)-5,5″,6,6″-tetracarboxylic acid, norbornane-2-spiro - α-cyclohexanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid (also known as "norbornane-2-spiro-2'-cyclohexanone-6'-spiro- 2″-norbornane-5,5″,6,6″-tetracarboxylic acid”), methylnorbornane-2-spiro-α-cyclohexanone-α′-spiro-2″-(methylnorbornane)-5 ,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclopropanone-α'-spiro-2''-norbornane-5,5'',6,6''- Tetracarboxylic acid, norbornane-2-spiro-α-cyclobutanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclo Heptanone -α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclooctanone-α'-spiro-2''-norbornane -5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclononanone-α'-spiro-2''-norbornane-5,5'',6,6''- Tetracarboxylic acid, norbornane-2-spiro-α-cyclodecanone-α′-spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic acid, norbornane-2-spiro-α-cyclo Undecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclododecanone-α'-spiro-2'' - norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotridecanone-α'-spiro-2''-norbornane-5,5'',6, 6″-tetracarboxylic acid, norbornane-2-spiro-α-cyclotetradecanone-α′-spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic acid, norbornane- 2-spiro-α-cyclopentadecanone-α′-spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclopenta non)-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclohexanone)-α'-spiro-2' Tetracarboxylic acids such as '-norbornane-5,5'', 6,6''-tetracarboxylic acid and acid anhydrides thereof can be mentioned. Among these, dianhydrides having two acid anhydride structures are preferred, particularly 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic acid Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride is preferred, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic An acid dianhydride is more preferred, and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride is even more preferred. In addition, these may be used independently and may use 2 or more types together.

The aromatic tetracarboxylic anhydrides used in the present invention include 4,4′-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4′-oxydiphthalic acid, bis(1,3-dioxo-1,3 -dihydro-2-benzofuran-5-carboxylic acid) 1,4-phenylene, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-yl)benzene-1,4-dicarboxylate, 4,4′-[4,4′-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarbon acid, 3,3′,4,4′-benzophenonetetracarboxylic acid, 4,4′-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(toluene-2, 5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(1,4-xylene-2 ,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[4,4′-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(4 -isopropyl-toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[4,4′-(3-oxo-1,3-dihydro-2-benzofuran-1,1 -diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[4,4′-(3H-2,1-benzoxathiol-1,1-dioxide -3,3-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-benzophenonetetracarboxylic acid, 4,4′-[(3H-2,1- Benzoxathiol-1,1-dioxide-3,3-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[(3H-2,1-benz oxathiol-1,1-dioxide-3,3-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4′-[4,4′- (3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(4-isopropyl-toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4 '-[4,4'-(3H-2,1-benzoxathi ol-1,1-dioxide-3,3-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 3,3′,4,4′-benzophenonetetracarboxylic acid, 3 ,3′,4,4′-benzophenonetetracarboxylic acid, 3,3′,4,4′-diphenylsulfonetetracarboxylic acid, 3,3′,4,4′-biphenyltetracarboxylic acid, 2,3,3 ',4'-biphenyltetracarboxylic acid, pyromellitic acid, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]diphthalic acid, 4,4'- tetracarboxylic acids such as [spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]diphthalic acid and acid anhydrides thereof. Aromatic tetracarboxylic acids may be used alone, or two or more of them may be used in combination.

Tricarboxylic acids include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalenetricarboxylic acid, diphenylether-3,3′,4′-tricarboxylic acid, and diphenylsulfone-3,3′,4′-tricarboxylic acid. acids or hydrogenated products of the above aromatic tricarboxylic acids such as hexahydrotrimellitic acid; Glycol bistrimellitate, and their monoanhydrides and esters. Among these, monoanhydrides having one acid anhydride structure are preferred, and trimellitic anhydride and hexahydrotrimellitic anhydride are particularly preferred. In addition, these may be used individually and may be used in combination.

Dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid, or the above aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid. Hydrogenates of oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecadeic acid, dodecanedioic acid, 2-methylsuccinic acid, and their acid chlorides Alternatively, an esterified product and the like can be mentioned. Among these, aromatic dicarboxylic acids and hydrogenated products thereof are preferred, and terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid are particularly preferred. In addition, dicarboxylic acids may be used alone or in combination.

As carboxylic acids, the following structures are particularly preferred.

The diamines in the present invention are not particularly limited, and aromatic diamines, aliphatic diamines, and alicyclic diamines that are commonly used in polyimide synthesis, polyamideimide synthesis, and polyamide synthesis can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. Diamines may be used alone or in combination of two or more.

Examples of aromatic diamines include 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis (4-amino-2-trifluoromethylphenoxy)benzene, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 4,4′-bis(4-aminophenoxy)biphenyl, 4,4′- Bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone , 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4-amino-N-(4-aminophenyl)benzamide, 3,3'-diaminodiphenyl ether , 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 2,2′-trifluoromethyl-4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4 '-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4 '-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis [4-(4-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane, 1,2-bis[4-(4-aminophenoxy)phenyl]propane, 1 , 3-bis[4-(4-aminophenoxy)phenyl]propane, 2, 2-bis[4-(4-aminophenoxy)phenyl]propane, 1,1-bis[4-(4-aminophenoxy)phenyl]butane, 1,3-bis[4-(4-aminophenoxy)phenyl] Butane, 1,4-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,3-bis[4-(4-amino phenoxy)phenyl]butane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3-methylphenyl]propane, 2,2-bis[4-(4- aminophenoxy)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2- Bis[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexa Fluoropropane, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4 -aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfoxide, bis[ 4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 1,3-bis[4-(4 -aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis [(3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4 '-diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl ]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2- bis[4-(3-aminophenoxy)phenyl]ethane, bis[4-(3-aminophenoxy)phenyl]sulfoxide, 4,4′-bis[3-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4 '-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4- (4-amino-α,α-dimethylbenzyl)phenoxy]diphenylsulfone, bis[4-{4-(4-aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy) Phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6 -trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[ 4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-diphenoxybenzophenone, 3,4′-diamino-4,5′-diphenoxybenzophenone, 3, 3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3 '-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,3'- diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1, 3-bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-bis(4-amino-5-phenoxybenzoyl) noxybenzoyl)benzene, 1,4-bis(4-amino-5-phenoxybenzoyl)benzene, 1,3-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,4-bis(3-amino -4-biphenoxybenzoyl)benzene, 1,3-bis(4-amino-5-biphenoxybenzoyl)benzene, 1,4-bis(4-amino-5-biphenoxybenzoyl)benzene, 2,6-bis [4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzonitrile, 4,4′-[9H-fluorene-9,9-diyl]bisaniline (also known as “9,9-bis(4-aminophenyl ) fluorene”), spiro(xanthene-9,9′-fluorene)-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4′-[spiro(xanthene-9,9′-fluorene)-2,6 -diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]bisaniline, 5-amino-2-(p-aminophenyl ) benzoxazole, 6-amino-2-(p-aminophenyl)benzoxazole, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2 , 2′-p-phenylenebis(5-aminobenzoxazole), 2,2′-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-4-(6-amino benzoxazolo)benzene, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(4,4'-diaminodiphenyl) benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2 ,6-(3,4′-diaminodiphenyl)benzo[1,2-d:4,5-d′]bisoxazole, 2,6-(3,3′-diaminodiphenyl)benzo[1,2-d :5,4-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole and the like. In addition, some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with a halogen atom, an alkyl or alkoxyl group having 1 to 3 carbon atoms, or a cyano group, and Some or all of the hydrogen atoms in the alkyl or alkoxyl groups of 1 to 3 may be substituted with halogen atoms.

Alicyclic diamines include, for example, 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propyl cyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 4,4′-methylenebis(2,6-dimethylcyclohexylamine), 9,10-bis(4-aminophenyl)adenine, 2,4-bis(4- aminophenyl)cyclobutane-dimethyl-1,3-dicarboxylate, and the like. As diamines, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB) or 4,4'-diaminobenzanilide (DABA) is particularly preferred.

Molar content based on the divalent monomer of the unit structure derived from silsesquioxane compound A: (nA / (nA + nD)) × 100 (where nA is derived from the silsesquioxane compound A is a number obtained by dividing the total number of moles of the unit structure by the total number of the dicarboxylic acid anhydride groups and multiplying it by 2, and nD is the number of moles of the unit structure derived from the carboxylic acid) is 0.01 to 10 0 mol % is preferred. When the molar content of the silsesquioxane compound A is 0.01 mol% or more, the effect of complexing is obtained, and when the molar content is 10.0 mol% or less, the gel of the polyamic acid solution This makes it difficult to cause quenching, and it is easy to obtain stability over time. Therefore, more preferably, the molar content is 0.1 to 5.0 mol %.
The polyamic acid solution may further contain optional components such as adhesion imparting agents, surfactants, leveling agents, antioxidants, UV absorbers, chemical imidizing agents, and colorants. In addition, it may further contain a filler or the like that can be contained in the polyimide film.

<Preparation of polyimide film>
A uniform green film with a thickness of 1 to 100 μm can be obtained by casting a polyamic acid solution on a substrate and heating to volatilize the solvent. Substrates used for forming a film by such a casting method include polymer films, glass plates, silicon rubber plates, metal plates, and the like.

As the polymer film, for example, polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) can be used. In addition, when obtaining a green film with a predetermined thickness, a method of adjusting the concentration of the polyamic acid solution, a method of adjusting the gap between the coaters, and a method of repeatedly casting to obtain the desired film thickness are adopted. Thus, a substrate having a desired film thickness can be produced. Further, the obtained green film is thermally imidized to obtain a polyimide film.

The polyimide film may have a single layer structure, or may have a laminated structure of two or more layers. From the viewpoint of the physical strength of the polyimide film and the ease of peeling from the inorganic substrate, it preferably has a lamination structure of two or more layers, and may have a lamination structure of three or more layers. In this specification, the physical properties (yellowness index, total light transmittance, haze, etc.) in the case where the polyimide film has a laminate structure of two or more layers refer to the values of the entire polyimide film unless otherwise specified.

The thickness of the polyimide film is preferably 5 μm or more, more preferably 7 μm or more. Although the upper limit of the thickness of the polyimide film is not particularly limited, it is preferably 200 μm or less, more preferably 90 μm or less, and still more preferably 50 μm or less for use as a flexible electronic device. If it is too thin, it will be difficult to produce a film and transport it, and if it is too thick, it will be difficult to transport it with a roll.

The total light transmittance of the polyimide film in the present invention is preferably 75% or more, more preferably 85% or more, even more preferably 87% or more, and still more preferably 88% or more. Although the upper limit of the total light transmittance of the polyimide film is not particularly limited, it is preferably 98% or less, more preferably 97% or less for use as a flexible electronic device.

The haze of the polyimide film in the present invention is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.5 or less, and still more preferably 0.3 or less.

The yellowness index of the polyimide film in the present invention (hereinafter also referred to as "yellow index" or "YI") is preferably 20 or less, more preferably 15 or less, still more preferably 10 or less, still more preferably 5 or less. The lower limit of the yellowness index of the polyimide film is not particularly limited, but in order to use it as a flexible electronic device, it is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more. is.

The thickness direction retardation (Rth) of the polyimide film in the present invention is preferably 500 nm or less, more preferably 300 nm or less, still more preferably 200 nm or less, and still more preferably 100 nm or less. Although the lower limit of Rth of the polyimide film is not particularly limited, it is preferably 0.1 nm or more, more preferably 0.5 nm or more for use as a flexible electronic device.

The highly colorless and transparent polyimide film exhibiting the coefficient of linear expansion (CTE) of the present invention can also be realized by stretching in the process of forming the polyimide film. In such a stretching operation, a polyimide solution is applied to a polyimide film-producing support, dried to form a polyimide film containing a solvent of 1 to 50% by mass, and further on a polyimide film-producing support or peeled off from the support. 1.5 to 4.0 times in the MD direction and 1.4 to 3.0 times in the TD direction in the process of drying the polyimide film containing 1 to 50% by mass of solvent at a high temperature. It can be realized by stretching to In this case, an unstretched thermoplastic polymer film is used as a support for producing a polyimide film, and after stretching the thermoplastic polymer film and the polyimide film at the same time, the stretched polyimide film is peeled off from the thermoplastic polymer film. In particular, it is possible to prevent scratches from entering the polyimide film during stretching in the MD direction, and it is possible to obtain a polyimide film of higher quality and colorless transparency.

The average coefficient of linear expansion (CTE) between 50°C and 200°C of the polyimide film is preferably 40 ppm/K or less. More preferably, it is 35 ppm/K or less. Moreover, it is preferably -10 ppm/K or more, more preferably -5 ppm/K or more. When the CTE is within the above range, the difference in coefficient of linear expansion with a general support (inorganic substrate) can be kept small, and the polyimide film and the inorganic substrate are peeled off even when subjected to a process of applying heat. You can avoid warping the whole body. Here, CTE is a factor representing reversible expansion and contraction with respect to temperature. The method for measuring the CTE of the polyimide film is according to the method described in Examples.

The polyimide film may contain a filler. The filler is not particularly limited, and includes silica, carbon, ceramics, etc. Among them, silica is preferable. These fillers may be used alone or in combination of two or more. Addition of the filler imparts projections to the surface of the polyimide film, thereby increasing the slipperiness of the polyimide film surface. Also, by adding a filler, the CTE and Rth of the polyimide film can be kept low. The average particle size of the filler is preferably 1 nm or more, more preferably 5 nm or more. Also, it is preferably 1 μm or less, more preferably 500 nm or less, and still more preferably 100 nm or less.

The content of the filler in the polyimide film is preferably adjusted according to the average particle size of the filler. When the particle size of the filler is 30 nm or more, it is preferably 0.01 to 5% by mass, more preferably 0.01 to 3% by mass, still more preferably 0.01 to 2% by mass, and particularly It is preferably 0.01 to 1% by mass. On the other hand, when the average particle diameter is less than 30 nm, it is preferably 0.01 to 50% by mass, more preferably 0.01 to 40% by mass, still more preferably 0.01 to 30% by mass, Particularly preferably, it is 0.01 to 20% by mass. By adjusting the content within the above range, it is possible to keep the polyimide film surface highly slippery without impairing the transparency of the polyimide film, and further to keep the CTE and Rth of the polyimide film low.

The method of adding a filler in a polyimide film is not particularly limited, but when preparing the above-mentioned polyamic acid (polyimide precursor) solution, or after preparation, a method of adding powder, a form of filler / solvent (slurry ), and the method of adding in the form of a slurry is particularly preferred. The slurry is not particularly limited, but a slurry in which silica having an average particle size of 10 nm is dispersed in N,N-dimethylacetamide (DMAC) at a concentration of 20% by mass (for example, "Snowtex (registered trademark) DMAC manufactured by Nissan Chemical Industries, Ltd. -ST" and a slurry in which silica having an average particle size of 80 nm is dispersed in N,N-dimethylacetamide (DMAC) at a concentration of 20% by mass (for example, Nissan Chemical Industries, Ltd. "Snowtex (registered trademark) DMAC-ST- ZL”), a slurry in which silica having an average particle size of 10 nm is dispersed in N-methylpyrrolidone (NMP) at a concentration of 20% by mass (for example, “Snowtex (registered trademark) NMP-ST” manufactured by Nissan Chemical Industries, Ltd.). be done.
The polyimide film may contain a coloring agent. For example, by mixing a pale yellow polyimide film with a blue colorant, the YI of the film can be reduced.
Examples of the coloring agent include organic pigments, inorganic pigments, and dyes. Organic pigments and inorganic pigments are preferred in order to improve the heat resistance, reliability, and light resistance of the colored film.
Examples of organic pigments include diketopyrrolopyrrole pigments; azo pigments such as azo, disazo and polyazo; phthalocyanine pigments such as copper phthalocyanine, halogenated copper phthalocyanine, and metal-free phthalocyanine; Anthraquinone pigments such as pyrimidine, flavanthrone, anthanthrone, indanthrone, pyranthrone, and violanthrone; quinacridone pigments; dioxazine pigments; perinone pigments; perylene pigments; quinophthalone-based pigments; threne-based pigments; and metal complex-based pigments.
Examples of inorganic pigments include titanium oxide, zinc white, zinc sulfide, lead white, calcium carbonate, precipitated barium sulfate, white carbon, alumina white, kaolin clay, talc, bentonite, black iron oxide, cadmium red, red iron oxide, molybdenum. Red, molybdate orange, chrome vermilion, yellow lead, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, Viridian, titanium cobalt green, cobalt green, cobalt chrome green, victoria green, ultramarine blue, dark blue, cobalt blue, cerulean blue, cobalt silica blue, cobalt zinc silica blue, manganese violet, cobalt violet, and the like.
Dyes include, for example, azo dyes, anthraquinone dyes, condensed polycyclic aromatic carbonyl dyes, indigoid dyes, carbonium dyes, phthalocyanine dyes, methine dyes, and polymethine dyes.

The tensile breaking strength of the polyimide film is preferably 60 MPa or more, more preferably 120 MPa or more, and still more preferably 160 MPa or more. Although the upper limit of the tensile strength at break is not particularly limited, it is practically less than about 1000 MPa. When the tensile strength at break is 60 MPa or more, it is possible to prevent the polyimide film from breaking when it is peeled off from the inorganic substrate. The method for measuring the tensile strength at break of the polyimide film is according to the method described in Examples. In addition, when the composition was coated on a glass substrate using a casting applicator, the two directions perpendicular to and parallel to the application of the casting applicator were defined as (MD direction) and (TD direction), respectively. The same applies to the following tensile elongation at break and tensile modulus.

The tensile elongation at break of the polyimide film is preferably 1% or more, more preferably 5% or more, and still more preferably 10% or more. When the tensile elongation at break is 5% or more, the handleability is excellent. The method for measuring the tensile elongation at break of the polyimide film is according to the method described in Examples.

The tensile modulus of the polyimide film is preferably 2 GPa or more, more preferably 3 GPa or more, and still more preferably 4 GPa or more. When the tensile elastic modulus is 3 GPa or more, the polyimide film undergoes little elongation deformation when peeled from the inorganic substrate, and is excellent in handleability. The tensile modulus is preferably 20 GPa or less, more preferably 12 GPa or less, and even more preferably 10 GPa or less. When the tensile modulus is 20 GPa or less, the polyimide film can be used as a flexible film. The method for measuring the tensile modulus of the polyimide film is according to the method described in Examples.

The polyimide film is preferably obtained in the form of being wound as a long polyimide film having a width of 300 mm or more and a length of 10 m or more at the time of its production. Morphology is more preferred. When the polyimide film is wound into a roll, the polyimide film wound into a roll can be easily transported.

In the polyimide film, in order to ensure handleability and productivity, a lubricant (particles) having a particle diameter of about 10 to 1000 nm is added and contained in the polyimide film in an amount of about 0.03 to 3% by mass. It is preferable to provide the surface of the polyimide film with fine irregularities to ensure slipperiness.

In addition, when the polyimide film has a laminated structure of two or more layers, if the CTE of each layer differs, it causes warping, which is not preferable. Therefore, the CTE difference between the first polyimide film layer in contact with the inorganic substrate and the second polyimide film layer adjacent to the first polyimide film without contacting the inorganic substrate is preferably 40 ppm/K or less. , more preferably 30 ppm/K or less, and still more preferably 15 ppm/K or less. In particular, it is preferable that the thickest layer of the second polyimide film has a thickness within the above range. Moreover, it is preferable that the polyimide film has a symmetrical structure in the film thickness direction because warping is less likely to occur.

In the polyimide film having a laminated structure of two or more layers, particularly, the first polyimide film layer in contact with the inorganic substrate and the second polyimide film layer adjacent to the first polyimide film layer (hereinafter simply referred to as "second The thickness of the mixture at the interface with the second polyimide film layer)) is less than the sum of the thickness of one layer of the first polyimide film layer and the thickness of one layer of the second polyimide film layer. Although it is not particularly limited, it is preferably 99% or less of the sum of the thickness of one layer of the first polyimide film layer and the thickness of one layer of the second polyimide film layer, and 80% or less. It is more preferably 50% or less, and the lower limit is not particularly limited, but industrially, there is no problem if it is 10 nm or more, and it may be 20 nm or more. When there is a significant difference in the function of each layer and it is necessary to fully demonstrate each function without canceling each other, it is preferable to keep the mixed area in each layer to 50% or less, and 30% or less. It is more preferable to suppress it, and it is further preferable to suppress it to 10% or less.

Means for forming a layer with less mixing is not particularly limited, but rather than simultaneously producing two layers of the first polyimide film layer and the second polyimide film layer by solution casting, the first polyimide film layer or It is preferable to fabricate any one layer of the second polyimide film layer and fabricate the next layer after passing through the heating step. It includes both the intermediate stage and the completed heating process. It is better to make the next layer after the heating process is completed, but the finished film surface often has already lost reactivity, and since there are few functional groups on the surface, it is difficult to separate the two layers. Poor adhesive strength may cause problems in practical use. Therefore, even if there is little mixing, it is desirable to have an interface where the mixing occurs at a thickness of 10 nm or more.

By forming a two-layered film of materials (resins) with different physical properties, it is possible to produce films with various properties. Furthermore, by laminating in a symmetrical structure in the thickness direction (for example, first polyimide film layer / second polyimide film layer / first polyimide film layer), the CTE of the entire film is well balanced, and warping occurs. It can be a film that is difficult to peel off. In addition, it is conceivable to give characteristics to the spectral characteristics by making any one layer a layer that absorbs ultraviolet rays or infrared rays, or to control the incidence and emission of light by layers with different refractive indexes.

As a means for producing a film with a layer structure of two or more layers, simultaneous coating with a T-die capable of simultaneous ejection of two layers, sequential coating in which one layer is coated and then the next layer is coated, and one layer is coated and then dried. A method of coating the next layer after proceeding, a method of coating the next layer after finishing the film formation of one layer, or multilayering by heat lamination by inserting a thermoplastic layer. In this patent, various existing coating methods and multi-layering techniques can be appropriately incorporated.

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples as long as it does not exceed the gist thereof. In addition, each physical property value in the production examples and examples was measured by the following methods.

<Thickness measurement of polyimide film>
The thickness of the film was measured using a micrometer (Millitron 1245D manufactured by Fineruff Co.). In addition, the same measurement was performed 3 times and the arithmetic mean value was adopted.

<Total light transmittance>
The total light transmittance (TT) of the film was measured using a Hazemeter (NDH5000, manufactured by Nippon Denshoku Co., Ltd.). A D65 lamp was used as the light source. In addition, the same measurement was performed 3 times and the arithmetic mean value was adopted.

<Haze>
The haze of the film was measured using a Hazemeter (NDH5000, manufactured by Nippon Denshoku Co., Ltd.). A D65 lamp was used as the light source. In addition, the same measurement was performed 3 times and the arithmetic mean value was adopted.

<Yellow index>
Using a color meter (ZE6000, manufactured by Nippon Denshoku Co., Ltd.) and a C2 light source, the tristimulus values XYZ values of the film were measured according to ASTM D1925, and the yellowness index (YI) was calculated according to the following formula. In addition, the same measurement was performed 3 times and the arithmetic mean value was adopted.

YI=100×(1.28X−1.06Z)/Y
<Glass transition temperature (Tg), coefficient of linear expansion (CTE)>
It was measured using a TMA (TMA4000S, BRUKER AXIS). The film was cut into strips of width 15 mm×length 2 mm, and set in the device with a chuck distance of 10 mm and a load of 5 gf. In an argon atmosphere, the temperature was raised to 250°C at a rate of 20°C/min, and then lowered to 30°C at a rate of 5°C/min. After that, the temperature was raised at a rate of 10° C./min up to a temperature (Td1-20° C.) at which thermal decomposition does not occur. The CTE was calculated from the slope in the 200° C. to 50° C. interval during the temperature decrease, and the inflection point during the second temperature increase was defined as Tg.

<Tensile modulus, tensile strength, elongation, tensile product>
Using Tensilon (Autograph AG-IS, Shimadzu Corporation), the test was carried out as follows. A strip of 5 mm×50 mm in length was cut from the film in the flow direction (MD direction) at the time of coating to obtain a test piece. 30 mm of both ends of the strip were gripped with an air jaw chuck, and the tensile modulus, tensile strength at break and elongation at break in the MD direction were determined at room temperature at a tensile speed of 50 mm/min. The tensile modulus was determined from the initial elastic slope of the strain-stress curve. Measurement was performed at each level N=5, and the average value of 3 points excluding the maximum and minimum values was treated as data. The product of tensile strength at break and elongation at break was taken as the tensile product.

<1H NMR Measurement of ^{Silsesquioxane} Compound Having Acid Anhydride Group>
Using each sample, ¹ HNMR measurement was performed under the following conditions.
Apparatus: Bruker Biospin DPX400 (Examples 1-2) or Agilent 400MR (Examples 3-9)
Solvent: deuterated chloroform (CDCl ₃ ) (Examples 1-2) or deuterated DMSO (DMSO-d ₆ ) (Examples 3-9)
Sample concentration: 3 mg/1 mL
Measurement temperature: room temperature (24°C)
Resonance frequency: 400MHz
Accumulated times: 32 times

[Synthesis Example 1: Synthesis of thiol group-containing silsesquioxane compound 1]
11.8 g (60.0 mmol) of 3-mercaptopropyltrimethoxysilane, 2.72 g of methyltrimethoxysilane (20 .0 mmol) ([number of moles of component (a2)]/[total number of moles of component (a1) and component (a2)] = 0.25), ion-exchanged water 1.9 g ([water used for hydrolysis reaction number of moles]/[total number of moles of alkoxy groups contained in components (a1) and (a2)] (molar ratio) = 0.45), charged with 1.0 g of cation exchange resin, and hydrolyzed at room temperature for 30 minutes. reacted. After the reaction, the cation exchange resin was filtered off and diluted with 5 g of ethylene glycol dimethyl ether (DMG) to obtain a hydrolyzate solution.

Subsequently, 9 g of DMG and 0.05 g of a 25% aqueous solution of tetramethylammonium hydroxide were charged in another reaction vessel and heated to 80°C. The previous hydrolyzate solution was added dropwise thereto over 2 hours and 30 minutes. Tetramethylammonium hydroxide dissolved during the dropwise addition, and the reaction liquid became clear. After dropping, the mixture was allowed to react at 80°C for 15 minutes, and then cooled to 25°C. 0.5 g of a cation exchange resin was added thereto and stirred at room temperature for 4 hours. Tetramethylammonium hydroxide was adsorbed during stirring and the reaction became clear. By filtering off the cation exchange resin, a solution of thiol group-containing silsesquioxane (average number of thiol groups per molecule = 6) was obtained. Toluene was added, and the mixture was heated to 70° C. under reduced pressure to distill off the methanol and water generated by hydrolysis and part of the toluene. Toluene was added appropriately to adjust the final solid content concentration to 72% by mass.

[Synthesis Example 2: Synthesis of thiol group-containing silsesquioxane compound 2]
8.83 g (45.0 mmol) of 3-mercaptopropyltrimethoxysilane, 5.44 g (40.0 mmol) of methyltrimethoxysilane ([number of moles of component (a2)]/[of component (a1) and component (a2) total number of moles]=0.47), 2.0 g of ion-exchanged water ([number of moles of water used in hydrolysis reaction]/[total number of moles of alkoxy groups contained in components (a1) and (a2)] ( Synthesis was carried out in the same manner as in Synthesis Example 1 except that the molar ratio) was set to 0.45). The obtained thiol group-containing silsesquioxane had an average number of thiol groups per molecule of 4.5, and a final solid content concentration of 72% by mass.

[Synthesis Example 3: Synthesis of thiol group-containing silsesquioxane compound 3]
4.91 g (25.0 mmol) of 3-mercaptopropyltrimethoxysilane, 6.81 g (50.0 mmol) of methyltrimethoxysilane ([number of moles of component (a2)]/[of component (a1) and component (a2) total number of moles]=0.67) 1.8 g of ion-exchanged water ([number of moles of water used in hydrolysis reaction]/[total number of moles of alkoxy groups contained in components (a1) and (a2)] (mol Synthesis was carried out in the same manner as in Synthesis Example 1 except that the ratio) was set to 0.45). The obtained thiol group-containing silsesquioxane had an average number of thiol groups per molecule of 2.5, and a final solid content concentration of 72% by mass.

[Example 1: Synthesis of silsesquioxane SQ1 having an acid anhydride group]
The following thiol group-containing silsesquioxane solution (manufactured by Arakawa Chemical Industries, Ltd., Compoceran SQ-109) 10 g (thiol group amount 16.7 mmol) and norbornenic anhydride 2.74 g (16.7 mmol) were placed in a reaction vessel. Then, while stirring, ultraviolet light (Spot Cure SP-11, manufactured by USHIO) was irradiated for 20 minutes to obtain silsesquioxane SQ1 having an acid anhydride group as a colorless transparent solution. NMR and IR measurements confirmed that the thiol group and norbornene were reacting. The resulting solution was filtered through a PTFE filter (pore size 10 μm) and then used for synthesizing a polyamic acid solution described later (the same applies to SQ3 to SQ9).

Compoceran SQ-109: condensate of methyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, molar ratio (former/(former + latter)) = 2/8, average number of thiol groups per molecule = 6, solvent PGMEA, solid content concentration 25% by mass.

The molar ratio and the average number of thiol groups per molecule were calculated as follows. In the ¹ H NMR measurement of Compoceran SQ-109, protons derived from methyl groups (δ = around 0.0 to 0.2, 3H) and protons derived from propylthiol groups (δ = around 0.2 to 0.8, 2H) The molar ratio of methyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane was calculated from the integral ratio of . The average number of thiol groups per molecule is determined by the ratio of the thiol group to the methyl group, the molecular weight per structural unit (SiO _1.5 Me = 67.1, SiO _1.5 C ₃ H ₆ SH = 127.2), the solution was calculated from the thiol group equivalent (600 g/eq.) and the solid content concentration of 25% by mass.

For reference, the results of NMR measurements are shown in FIGS. ¹ HNMR (CDCl ₃ ) spectra of SQ-109 (PGMEA solution in FIG. 2, PGMEA in FIG. 2, norbornenic anhydride in FIG. 3, and reaction mixture after reaction in FIG. 4) are shown. 4, the peaks (δ=6.3, etc.) derived from the double bond of norbornenic anhydride disappeared, suggesting that the reaction between the thiol group and the double bond proceeded.

[Example 2: Synthesis of silsesquioxane SQ2 having an acid anhydride group]
Thiol group-containing silsesquioxane solution (manufactured by Arakawa Chemical Industries, Ltd., Compoceran SQ-109) 10 g (thiol group amount 16.7 mmol), norbornenic anhydride 2.74 g (16.7 mmol), iron (III) chloride 1 mg was put into a reaction vessel and stirred for 10 minutes to obtain silsesquioxane SQ2 having an acid anhydride group as a pale yellow solution (yellow coloration is considered to be derived from iron chloride). NMR and IR measurements confirmed that the thiol group and norbornene were reacting.

For reference, FIG. 5 shows the ¹ HNMR (CDCl ₃ ) spectrum of the reaction mixture after the reaction as a result of NMR measurement. In FIG. 5, the peaks (δ=6.3, etc.) derived from the double bond of norbornenic anhydride disappeared, suggesting that the reaction between the thiol group and the double bond proceeded.

[Example 3: Synthesis of silsesquioxane SQ3 having an acid anhydride group]
20 g of the solution of the thiol group-containing silsesquioxane compound 1 obtained in Synthesis Example 1 (thiol group amount 97.0 mmol), 15.9 g (97.0 mmol) of norbornenic anhydride, and 10.0 g of PGMEA were placed in a reaction vessel. , while stirring, ultraviolet light (Spot Cure SP-11, manufactured by USHIO) was irradiated for 20 minutes to obtain silsesquioxane SQ3 having an acid anhydride group as a colorless transparent solution. NMR and IR measurements confirmed that the thiol group and norbornene were reacting.

[Example 4: Synthesis of silsesquioxane SQ4 having an acid anhydride group]
20 g of the solution of the thiol group-containing silsesquioxane compound 2 obtained in Synthesis Example 2 (thiol group amount 77.9 mmol), norbornenic anhydride 12.8 g (77.9 mmol), and PGMEA 10.0 g were placed in a reaction vessel. , while stirring, ultraviolet light (Spot Cure SP-11, manufactured by USHIO) was irradiated for 20 minutes to obtain silsesquioxane SQ4 having an acid anhydride group as a colorless transparent solution. NMR and IR measurements confirmed that the thiol group and norbornene were reacting.

[Example 5: Synthesis of silsesquioxane SQ5 having an acid anhydride group]
20 g of the solution of the thiol group-containing silsesquioxane compound 3 obtained in Synthesis Example 3 (thiol group amount 54.5 mmol), 8.95 g (54.5 mmol) of 5-norbornene-2,3-dicarboxylic anhydride, 10.0 g of PGMEA was placed in a reaction vessel and irradiated with ultraviolet light (Spot Cure SP-11, manufactured by USHIO) for 20 minutes while stirring to obtain silsesquioxane SQ5 having an acid anhydride group as a colorless transparent solution. rice field. NMR and IR measurements confirmed that the thiol group and 5-norbornene-2,3-dicarboxylic anhydride reacted.

[Example 6: Synthesis of silsesquioxane SQ6 having an acid anhydride group]
A thiol group-containing trialkoxysilane solution (manufactured by Arakawa Chemical Industries, Ltd., Compoceran SQ-109) 6 g (thiol group amount 10.0 mmol) and allylsuccinic anhydride 1.40 g (10.0 mmol) were placed in a reaction vessel, By irradiating with ultraviolet light (MAX-303, manufactured by Asahi Spectrosco Co., Ltd.) for 20 minutes while stirring, silsesquioxane SQ6 having an acid anhydride group was obtained as a colorless transparent solution. NMR and IR measurements confirmed that the thiol group and allylsuccinic anhydride were reacting.

[Example 7: Synthesis of silsesquioxane SQ7 having an acid anhydride group]
Thiol group-containing trialkoxysilane solution (manufactured by Arakawa Chemical Industries, Ltd., Compoceran SQ-109) 6 g (thiol group amount 10.0 mmol), exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic acid 1.66 g (10.0 mmol) of the anhydride is placed in a reaction vessel and irradiated with ultraviolet light (MAX-303, manufactured by Asahi Spectrosco Co., Ltd.) for 20 minutes while stirring to form a colorless and transparent solution having an acid anhydride group. Sesquioxane SQ7 was obtained. NMR and IR measurements confirmed that the thiol group and exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride were reacted.

[Example 8: Synthesis of silsesquioxane SQ8 having an acid anhydride group]
Thiol group-containing trialkoxysilane solution (Compoceran SQ-109, manufactured by Arakawa Chemical Industries, Ltd.) 3 g (thiol group amount 5.0 mmol), 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydride 0.94 g (5.0 mmol) of the compound and γ-butyrolactone (5 mL) were placed in a reaction vessel and irradiated with ultraviolet light (MAX-303, manufactured by Asahi Spectrosco Co., Ltd.) for 20 minutes while stirring to give an acid as a yellow transparent solution. Silsesquioxane SQ8 with anhydride groups was obtained. It was confirmed by NMR and IR measurements that the thiol group and 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydride were reacted.

[Example 9: Synthesis of silsesquioxane SQ9 having an acid anhydride group]
A thiol group-containing trialkoxysilane solution (Compoceran SQ-109, manufactured by Arakawa Chemical Industries, Ltd.) 6 g (thiol group amount 10.0 mmol) was placed in a reaction vessel, and 2.10 g of trimellitic anhydride chloride (10.0 mmol) was added with stirring. 0 mmol) was added slowly. By stirring at room temperature for 24 hours, silsesquioxane SQ9 having an acid anhydride group was obtained as a colorless transparent solution. NMR and IR measurements confirmed that the thiol group and the acid chloride group were reacting.

[Comparative Example 1: Synthesis of terminal dicarboxylic anhydride silsesquioxane SQN1 (containing no thioether moiety)]
A thioether moiety-free silsesquioxane SQN1 having a structure represented by the following chemical formula was synthesized by the method described in Example 1 of International Publication WO2010/095329A1.

[Comparative Example 2: Synthesis of terminal dicarboxylic acid anhydride silsesquioxane SQN2 (containing no thioether moiety)]
By the method described in Example 2 of International Publication WO2010/095329A1, a silsesquioxane SQN2 containing no thioether moiety and having a structure represented by the following chemical formula was synthesized.

[Production Example A: Synthesis of polyamic acid solution A]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 5.88 g) and 4,4'-diamino-2,2 were introduced while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. '-Bis (trifluoromethyl) biphenyl (TFMB, 9.74 g), SQ1 solution (0.655 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 125.0 g), and then at 25 ° C. for 24 hours. Polyamic acid solution A was obtained by stirring (molar ratio of CBDA/SQ1/TFMB=0.985/0.015/1.00). Here, the molar ratio of SQ1 is a value calculated based on the divalent acid anhydride group. Specifically, the total number of moles of the unit structure derived from the silsesquioxane compound A is It is calculated as a number divided by the total number of groups and doubled (the same applies to the following molar ratios).

[Production Example B: Synthesis of polyamic acid solution B]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 5.88 g), 4,4′-diaminobenzanilide (DABA , 6.92 g) and SQ1 solution (0.655 g) were added and dissolved in N,N-dimethylacetamide (DMAc, 133.7 g), and then stirred for 24 hours at 25 ° C. Polyamic acid solution B was obtained. (molar ratio of CBDA/SQ1/DABA=0.985/0.015/1.00).

[Production Example Ca: Synthesis of polyamic acid solution Ca]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.88 g), add SQ1 solution (0.328 g), dissolve in N,N-dimethylacetamide (DMAc, 67.0 g), and then stir at 25 ° C. for 24 hours to remove polyamic acid solution Ca. (molar ratio of PMDA/SQ1/TFMB=0.985/0.015/1.00).

[Production Example Cb: Synthesis of polyamic acid solution Cb]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.90 g), add SQ3 solution (0.227 g), dissolve in N-methyl-2-pyrrolidone (NMP, 66.0 g), and then stir at 25 ° C. for 24 hours to obtain polyamic acid solution Cb. (molar ratio of PMDA/SQ3/TFMB=0.98/0.02/1.00).

[Production Example Cc: Synthesis of polyamic acid solution Cc]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.90 g), add SQ4 solution (0.258 g), dissolve in N-methyl-2-pyrrolidone (NMP, 66.0 g), and then stir at 25 ° C. for 24 hours to obtain polyamic acid solution Cc. (molar ratio of PMDA/SQ4/TFMB=0.98/0.02/1.00).

[Production Example Cd: Synthesis of polyamic acid solution Cd]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.90 g), add SQ5 solution (0.325 g), dissolve in N-methyl-2-pyrrolidone (NMP, 66.0 g), and then stir at 25 ° C. for 24 hours to obtain polyamic acid solution Cd. (molar ratio of PMDA/SQ5/TFMB=0.98/0.02/1.00).

[Production Example Ce: Synthesis of polyamic acid solution Ce]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.90 g), add SQ9 solution (0.354 g), dissolve in N-methyl-2-pyrrolidone (NMP, 66.0 g), and then stir at 25 ° C. for 24 hours to obtain polyamic acid solution Ce. (molar ratio of PMDA/SQ9/TFMB=0.985/0.015/1.00).

[Production Example D: Synthesis of polyamic acid solution D]
Pyromellitic dianhydride (PMDA, 3.27 g), 4,4'-diaminobenzanilide (DABA, 3.47 g), SQ1 solution ( 0.328 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 63.0 g), and stirred at 25 ° C. for 24 hours to obtain a polyamic acid solution D (molar ratio of PMDA/SQ1/DABA = 0.985/0.015/1.00).

[Comparative Production Example A1: Synthesis of polyamic acid solution A1]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 19.6 g) and 4,4'-diamino-2,2 were introduced while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. '-bis (trifluoromethyl) biphenyl (TFMB, 32.3 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 279.0 g), and then stirred at 25 ° C. for 24 hours to obtain a polyamic acid solution A1. (molar ratio of CBDA/TFMB=1.00/1.00).

[Comparative Production Example B1: Synthesis of polyamic acid solution B1]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 3.98 g), 4,4'-diaminobenzanilide (DABA , 4.58 g) was added and dissolved in N,N-dimethylacetamide (DMAc, 76.0 g), and then stirred at 25 ° C. for 24 hours to obtain a polyamic acid solution B1 (molar ratio of CBDA / DABA = 1.00/1.00).

[Production Example B2: Synthesis of polyamic acid solution B2]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 2.94 g), 4,4'-diaminobenzanilide (DABA , 3.54 g), SQ1 solution (1.00 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 90 g), and then stirred at 25 ° C. for 24 hours to obtain a polyamic acid solution B2 (CBDA /SQ1/DABA molar ratio = 0.955/0.045/1.00).

[Comparative Production Example B4: Synthesis of polyamic acid solution B4]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 3.98 g), 4,4'-diaminobenzanilide (DABA , 4.55 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 76.0 g), and stirred at 25° C. for 24 hours. Then, SQ-109 (0.546 g) was added and stirred for 24 hours to obtain polyamic acid solution B4 (molar ratio of CBDA/DABA/SQ-109=1.00/1.00/0. 01).

[Comparative Production Example B5: Synthesis of polyamic acid solution B5]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 3.98 g), 4,4'-diaminobenzanilide (DABA , 4.55 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 76.0 g), and stirred at 25° C. for 24 hours. Then, SQ-109 (8.19 g) was added and stirred for 24 hours to obtain polyamic acid solution B5 (molar ratio of CBDA/DABA/SQ-109=1.00/1.00/0. 15).

[Comparative Production Example B6: Synthesis of polyamic acid solution B6]
1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, 3.98 g), 4,4'-diaminobenzanilide (DABA , 4.55 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 76.0 g), and stirred at 25° C. for 24 hours. Then, SQ-109 (27.3 g) was added and stirred for 24 hours to obtain polyamic acid solution B6 (molar ratio of CBDA/DABA/SQ-109=1.00/1.00/0. 50).

[Comparative Production Example C1: Synthesis of polyamic acid solution C1]
Pyromellitic dianhydride (PMDA, 6.54 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 9.61 g) was added, dissolved in N,N-dimethylacetamide (DMAc, 164.0 g), and stirred at 25° C. for 24 hours to obtain a polyamic acid solution C1 (PMDA/TFMB moles ratio=1.00/1.00).

[Comparative Production Example C2: Synthesis of polyamic acid solution C2]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.85 g) and SQN1 (0.070 g) were added and dissolved in N,N-dimethylacetamide (DMAc, 67.0 g), followed by stirring at 25°C for 24 hours to obtain polyamic acid solution C2. (molar ratio of PMDA/SQN1/TFMB=0.99/0.01/1.00).

[Comparative Production Example C3: Synthesis of polyamic acid solution C3]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were added while passing nitrogen through a reactor equipped with a nitrogen inlet tube and a stirring blade. (TFMB, 4.85 g) and SQN2 (0.081 g) were added and dissolved in N,N-dimethylacetamide (DMAc, 67.0 g), followed by stirring at 25°C for 24 hours to obtain polyamic acid solution C3. (molar ratio of PMDA/SQN2/TFMB=0.99/0.01/1.00).

[Comparative Production Example D1: Synthesis of polyamic acid solution D1]
Pyromellitic dianhydride (PMDA, 3.27 g) and 4,4′-diaminobenzanilide (DABA, 3.41 g) are introduced into a reactor equipped with a nitrogen inlet tube and a stirring blade while nitrogen is passed through. , N-dimethylacetamide (DMAc, 63.0 g) and stirred at 25° C. for 24 hours to obtain a polyamic acid solution D1 (molar ratio of PMDA/DABA=1.00/1.00).

The polyamic acid solutions obtained in the above production examples and comparative production examples were made into films by the following methods, and their optical properties, thermal properties, and mechanical properties were measured.

[Production Example 1]
Polyamic acid solution A was applied onto a polyester film (A4100, Toyobo product) using a casting applicator and heated at 100° C. for 18 minutes in a nitrogen atmosphere. The resulting green film was cut with a cutter, peeled off from the polyester film, and fixed to a metal frame. In a nitrogen atmosphere, the temperature was increased stepwise at a rate of 10°C/min, and the temperature was increased by heating sequentially at 200°C x 10 minutes, 250°C x 10 minutes, 300°C x 10 minutes, and 350°C x 10 minutes. imidization was performed. After standing to cool, the polyimide film was obtained by removing from the metal frame.

[Production Examples 2 to 5]
A polyimide film was obtained in the same manner as in Production Example 1, except that polyamic acid solution B, Ca-Ce, D, and B2 were used instead of polyamic acid solution A in Production Example 1. Table 1 shows the components used at that time and the evaluation results.

[Comparative Production Examples 1 to 9]
A polyimide film was obtained in the same manner as in Production Example 1 except that polyamic acid solutions A1, B1, B4, B5, B6, C1, C2, C3, and D1 were used instead of polyamic acid solution A in Production Example 1. rice field. Table 1 shows the components used at that time and the evaluation results.

As shown in Table 1, the polyimide films containing 1 mol % of SQ1 in the structure (Production Examples 1, 2, 3a and 4) have the same composition except that they do not contain SQ1 (Comparative Production Example 1 , 2, 6, and 9), the total light transmittance, haze, yellow index, Tg, and CTE are substantially the same, and the tensile product is increased.

Comparing Production Example 2, Comparative Production Example 3, Comparative Production Example 4, and Comparative Production Example 5, when SQ-109 having no acid anhydride group was mixed instead of SQ1 having an acid anhydride group at the end, As the addition amount was increased to 1%, 15%, and 50%, the polyamic acid solution and the polyimide film became cloudy. Further, when SQ-109 was added, no increase in tensile product was observed, and the film became brittle as the amount added increased.

Comparing Production Examples 3a to 3e, Comparative Production Example 6, Comparative Production Example 7, and Comparative Production Example 8, Production Examples 3a to 3e have an improved tensile product compared to Comparative Production Example 6, but the Comparative Production Example 7. Comparative Production Example 8 had a tensile product comparable to that of Comparative Production Example 6. Production Example 3a, Comparative Production Example 7, and Comparative Production Example 8 are all polyimides containing silsesquioxane having the same acid anhydride group (norbornenic anhydride) in the structure, but were used in Production Example 3a. SQ1 contains a thioether group between the acid anhydride group and the silsesquioxane structure, and SQN1 and SQN2 used in Comparative Production Examples 7 and 8 do not contain a thioether group. It was suggested that copolymerization of silsesquioxanes containing thioether groups in the structure is useful for improving the tensile product.
(Application example 1)
First, the polyimide film obtained in Production Example 3a (PMDA/TFMB/SQ1) was cut into a rectangle of 360 mm×460 mm. Next, UV/O ₃ irradiation was performed for 3 minutes using a UV/O ₃ irradiator (SKR1102N-03 manufactured by LAN Technical Co., Ltd.) for film surface treatment. At this time, the distance between the UV/O3 lamp and the film was ₃₀ mm.

Spray 3-aminopropyltrimethoxysilane (KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent on display glass (370 mm × 470 mm, 0.7 mm thick glass substrate: OA10G manufactured by Nippon Electric Glass Co., Ltd.) It was applied with a coater. The glass substrate used was washed with pure water, dried, irradiated with a UV/O ₃ irradiator (SKR1102N-03 manufactured by LAN Technical Co., Ltd.) for 1 minute, and dried.

Next, the glass substrate coated with the silane coupling agent is set on a roll laminator equipped with a silicone rubber roller. got wet.

The surface-treated surface of the polyimide film subjected to the surface treatment is superimposed so as to face the silane coupling agent-coated surface of the glass substrate, that is, the surface wetted with pure water, and the polyimide is sequentially applied from one side of the glass substrate with a rotating roll. A temporary laminate was obtained by laminating the glass substrate and the polyimide film by applying pressure while extruding pure water between the film and the glass substrate. The laminator used was a laminator with an effective roll width of 650 mm manufactured by MCK. It was 55% RH.

The resulting temporary laminate was heat-treated in a clean oven at 200°C for 10 minutes to obtain a laminate consisting of a polyimide film and a glass substrate.

A tungsten film (thickness: 75 nm) was formed on the polyimide film surface of the obtained laminate by the following steps, and a silicon oxide film (thickness: 150 nm) was laminated as an insulating film without being exposed to the atmosphere. Next, a silicon oxynitride film (thickness: 100 nm) serving as a base insulating film was formed by plasma CVD, and an amorphous silicon film (thickness: 54 nm) was laminated without being exposed to the atmosphere.

A TFT element was fabricated using the obtained amorphous silicon film. First, an amorphous silicon thin film is patterned to form a silicon region of a predetermined shape, and then a gate insulating film is formed, a gate electrode is formed, an active region is doped to form a source region or a drain region, and an interlayer insulating film is formed. , formation of a source electrode and a drain electrode, and activation treatment were performed to fabricate an array of P-channel TFTs.

A UV-YAG laser is used to burn off the polyimide film part along the inside of the outer circumference of the TFT array by about 0.5 mm. got an array. The peeling was possible with very little force, and the peeling was possible without damaging the TFT. The resulting flexible TFT array was wound around a round bar of 5 mm in diameter without deterioration in performance and maintained good characteristics.

As described above, the polyimide film of the present invention has good mechanical properties while maintaining the same level of optical properties and thermal properties as compared to the case where the silsesquioxane compound is not contained. . The polyimide film of the present invention has excellent optical properties, colorless transparency, excellent mechanical properties, and exhibits a relatively low CTE. After that, various electronic device processing is performed on the film, and finally the film is separated from the inorganic substrate, whereby a flexible electronic device can be produced.

Claims

A silsesquioxane compound having a dicarboxylic anhydride group,
thiol group-containing trialkoxysilanes a1 represented by the general formula: R 1 Si(OR 2 ) 3 ;
(Wherein, R 1 is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R 2 is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
trialkoxysilanes a2 having no thiol group;
a thiol group of the condensate B of
said reactive group of dicarboxylic anhydride C having at least one reactive group selected from vinyl group, alkenyl group, cycloalkenyl group, alkynyl group, and acid chloride group;
A silsesquioxane compound formed by the reaction of
A silsesquioxane compound having a dicarboxylic anhydride group and having structural units represented by the following general formulas (1) and (2).

(In the formula, Q 1 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and Q 2 is a single bond, a hydrocarbon group having 1 to 8 carbon atoms, an organic group in which one or more carbon atoms of the hydrocarbon group having 1 to 8 carbon atoms are substituted with oxygen, or a carbonyl group, and X is carbon- a carbon bond, or an aliphatic ring having 4 to 10 carbon atoms, an aromatic ring having 6 to 10 carbon atoms, or a heterocyclic ring in which some of the carbon atoms constituting these are substituted with oxygen or sulfur; One or more of the hydrogens bonded to may be substituted with a hydrocarbon group, and 1.0 ≤ m ≤ 2.0 and 1.4 ≤ n ≤ 1.6.)

(Wherein, Q 3 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms, and 1.4 ≤ n ≤ 1.6.)
The molar ratio of the trialkoxysilanes a2 ([moles of a2]/[moles of a1+moles of a2]), or the molar ratio of the structural units represented by the general formula (2) ([structural unit (2 )]/[Structural unit (1)+Structural unit (2)]) is 0.1 or more and 0.7 or less, The silsesquioxane compound according to claim 1 or 2.
The silsesquioxane compound according to claim 1 or 3, wherein the dicarboxylic anhydride C is a compound represented by a chemical formula selected from the following.

(Wherein, Rx represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
A method for producing a silsesquioxane compound having a dicarboxylic anhydride group, comprising the following steps in order.
thiol group-containing trialkoxysilanes a1 represented by the general formula: R 1 Si(OR 2 ) 3 ;
(Wherein, R 1 is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms. represents an organic group substituted with a thiol group, R 2 is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 4 to 8 carbon atoms, Or represents an aromatic hydrocarbon group having 6 to 8 carbon atoms.)
A first step of hydrolyzing a trialkoxysilane a2 having no thiol group and water using an acidic catalyst to obtain a reaction mixture x;
a second step of removing the acidic catalyst from the reaction mixture x to obtain a reaction mixture y;
A third step of obtaining a condensate B having a thiol group by mixing and condensing a polar solvent containing a basic catalyst and the reaction mixture y, and the condensate B, a vinyl group, an alkenyl group, a cycloalkenyl group, A fourth step of reacting with a dicarboxylic anhydride C having at least one reactive group selected from an alkynyl group and an acid chloride group.