TWI633154B - Resin composition for forming porous membrane and porous membrane - Google Patents

Abstract

A compound or polymer containing a thermally decomposable functional group that decomposes due to heat and generates gas.

Description

Resin composition for forming porous membrane and porous membrane

The present invention relates to a resin composition for forming a porous membrane and a porous membrane.

Polymer porous membranes are used for various applications such as battery separators or electrolytic capacitor separators, dust collection, precision filtration, and membrane separation. In particular, the polyimide porous membrane is expected to expand its application because it has excellent heat resistance, mechanical properties, and chemical resistance derived from polyimide. As a method for producing a polyimide porous membrane, methods such as non-solvent-induced phase separation (NIPS), vapor-induced phase separation (VIPS), and thermally-induced phase separation (TIPS) are known.

Patent Document 1 discloses a method for producing a polyimide porous membrane by a non-solvent-induced phase separation method. The method for manufacturing a polyimide porous film disclosed here is to use a polyimide precursor varnish cast film obtained from a biphenyltetracarboxylic acid component and a diamine component to laminate a porous film and then impregnate The method of operation in non-solvent.

Patent Document 2 discloses a method for producing a porous polyimide membrane by a vapor-induced phase separation method. The manufacturing method of the polyimide porous membrane disclosed here utilizes the precursor of polyimide A solution of 0.3 to 60% by weight and a solvent of 99.7 to 40% by weight is cast into a film, and the film of the polyimide precursor obtained is subjected to vapor exposure treatment, and then immersed or contacted with solidification The method of operation in the solvent.

Patent Document 3 discloses a method of manufacturing a polyimide porous membrane without using a coagulation bath. The method for producing a polyimide porous membrane disclosed here is to pre-mix a high-boiling non-solvent in a polyamide precursor solution (polyamide acid solution), and then perform film formation, followed by heating. Dry casting of porous membranes. More specifically, in this document, it is disclosed that an ether system containing a polyimide precursor and an amide-based solvent and having a boiling point higher than the amide-based solvent by 15 ° C or higher (preferably 50 ° C or higher) is used. The solution of the polyimide precursor solution of the solvent is cast on the substrate to form a polyimide precursor film, which is then dried by heating ‧ the operation of the polyimide porous film for the operation of imidization. In this document, it is described that this method uses a solvent having a boiling point different from each other to generate foam when the polyimide precursor film is heated by imidization and obtain a porous polyimide porous film with high porosity. .

Patent Document 4 discloses that a polyimide porous film produced according to the method described in Patent Document 3 is subjected to surface treatment such as surface polishing treatment or laser irradiation to obtain a polyimide with more improved porosity. Porous imine membrane.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-153480

[Patent Document 2] Japanese Patent Laid-Open No. 11-265347

[Patent Document 3] Japanese Unexamined Patent Publication No. 2007-211136 (Japanese Patent No. 4947989)

[Patent Document 4] Japanese Unexamined Patent Publication No. 2013-64122

The method for manufacturing a polyimide porous membrane disclosed in Patent Documents 1 and 2 requires an additional operation called "immersion or contact with a coagulation solvent", so it is used as a polyimide porous membrane (porous film) The industrial manufacturing method is unfavorable. Furthermore, when industrially manufacturing porous polyimide porous films, it is difficult to say that the coagulation bath and the like must be strictly controlled, which is advantageous.

The method for producing a polyimide porous membrane described in Patent Document 3 also reveals from the description in Patent Document 4 that it has a problem that it is difficult to obtain a sufficiently high porosity polyimide porous membrane. That is, by using the method for manufacturing a polyimide porous membrane described in Patent Document 3, a relatively thick porous membrane having a thickness of 300 μm or more can be obtained, but if the thickness of the membrane is thin, the porosity significantly decreases, so It is difficult to produce a porous membrane with a high porosity at a film thickness of 100 μm or less. This is considered to be because the method described in this document casts the solution of the polyimide precursor solution on the surface of the support and heats and dries the atmospheric contact surface (A surface) of the polyimide precursor solution film The reason why a polyimide skin layer is formed makes it difficult to obtain a porous membrane with high air permeability that has pores on both sides of the porous membrane. This recognition is also supported by the description of Patent Document 4.

Therefore, the object of the present invention is to provide a porous polyimide porous membrane which is excellent in heat resistance and chemical resistance and has a high porosity (porosity).

The inventors have repeatedly studied the results in order to solve the above-mentioned problems, and completed the present invention. That is, the present invention has the following gist.

1. A resin composition for forming a porous film, characterized by containing a compound or a polymer compound having a thermally decomposable functional group that decomposes due to heat and generates gas.

2. The resin composition for forming a porous film according to 1, wherein the resin composition for forming a porous film contains the polymer compound, and the polymer compound contains a monomer having the thermally decomposable functional group Polymers that are polymerized or copolymerized.

3. The resin composition for forming a porous membrane according to 1 or 2, wherein the resin composition for forming a porous membrane includes a polymer or a copolymer, and the polymer or copolymer includes a tetracarboxylic acid derivative selected from the group consisting of Polyimide precursor obtained by reacting with diamine component and polyimide obtained by imidization, or polyurea obtained by reacting diisocyanate with diamine component, at least 1 in the group Any one of the polymers or copolymers containing at least one of the foregoing is obtained by polymerizing or copolymerizing the monomer having a thermally decomposable functional group.

4. The resin composition for forming a porous membrane according to 3, wherein the resin composition for forming a porous membrane includes a polyimide precursor and its amide obtained by reacting a tetracarboxylic acid derivative with a diamine component Polyimide Imine, and the aforementioned mono-system diamine compound having a thermally decomposable functional group.

5. The resin composition for forming a porous film according to 4, wherein the diamine component includes the diamine having the thermally decomposable functional group and other diamine compounds.

6. The resin composition for forming a porous film according to any one of 1 to 5, wherein the thermally decomposable functional group is a t-butoxycarbonyl group (Boc group).

7. The resin composition for forming a porous film according to any one of 1 to 6, wherein the resin composition for forming a porous film contains a strong acid.

8. The resin composition for forming a porous film according to any one of claims 1 to 7, wherein 1 g of the resin composition contains 0.5 mmol or more of t-butoxycarbonyl group (Boc group).

9. The resin composition for forming a porous film according to any one of claims 1 to 8, wherein 1 g of the resin composition contains a total of 2 mmol or more of acidic functional groups and acidic compounds.

10. A porous membrane obtained by a resin composition for forming a porous membrane containing a compound or a polymer compound having a thermally decomposable functional group that decomposes due to heat and generates gas, and is characterized by including voids The void contains gas generated by thermal decomposition of the aforementioned thermally decomposable functional group or air replacing the gas.

According to the present invention, it is possible to provide a porous polyimide porous membrane having excellent heat resistance and chemical resistance and high porosity (porosity). In addition, compared with the conventional polyimide porous membrane, it can be manufactured more easily The formation of porous membranes can be expected to advance in various applications.

[Fig. 1] A SEM observation photograph of the cross section of the porous membrane of Example 2.

[Fig. 2] A SEM observation photograph of the cross section of the porous membrane of Example 3.

The present invention is explained in more detail below.

<Summary of the invention>

The present invention relates to a resin composition for forming a porous film that forms a polymer coating film containing a thermally decomposable functional group that decomposes due to heat and generates gas. The following is a detailed description of each component.

<Resin Composition for Porous Film Formation>

The resin composition for forming a porous film of the present invention means a composition containing a compound or a polymer compound having a thermally decomposable functional group and a solvent. Among them, it is preferable to use a polymer compound having a thermally decomposable functional group from the viewpoints of ease of production of the porous membrane and stability of the membrane.

That is, although the resin composition for forming a porous film basically contains at least one precursor or polymer for forming a polymer film (hereinafter, the precursor and polymer are also collectively referred to as a polymer), they are referred to here. polymer In it, a polymer having a thermally decomposable functional group may be included. In this case, the monomer used in the production of the polymer already contains a monomer having a thermally decomposable functional group, and the monomer reacts, polymerizes, or copolymerizes to become a polymer having a thermally decomposable functional group .

<Thermally decomposable functional group>

The thermally decomposable functional group used in the resin composition for forming a porous film of the present invention is not particularly limited as long as it is a functional group that generates gas by heating, but t-butoxy group Carbonyl group (Boc group), benzyloxycarbonyl group, 9-oxylmethyloxycarbonyl group, allyloxycarbonyl group and the like. From the viewpoint of degassing temperature and efficiency, t-butoxycarbonyl (Boc group) is particularly preferred.

<Polymer compound>

The polymer compound used in the resin composition for forming a porous film of the present invention is polyamic acid, polyamic acid ester, polyimide, polyurea, polyurethane, polyacrylate, polymethyl The structure of acrylate and the like is not particularly limited as long as the structure capable of efficiently introducing the thermally decomposable functional group is included. In addition to the polymer having the above structure, a copolymer including two or more structures selected from the above structure or including the above structure is included Copolymers with other structures (polymers and copolymers are also simply referred to as polymers), polymers selected from polyamic acid, polyamic acid ester, polyimide, and polyurea, including Choose copolymers of two or more structures, or copolymers containing these structures and other structures, from the viewpoint of mechanical strength and stability of the membrane. Look is better.

<Polyamide, Polyamide>

Polyamic acid and polyamic acid ester (hereinafter also referred to as polyimide precursor) are obtained by reacting tetracarboxylic acid derivatives and diamine components. After polyimide precursor is imidized, polyimide can be obtained.

In order to introduce the thermally decomposable functional group into the polyimide precursor, it is necessary to use a tetracarboxylic acid derivative into which the thermally decomposable functional group is introduced and / or a diamine into which the thermally decomposable functional group is introduced. Among them, it is preferable to use a diamine into which a thermally decomposable functional group is introduced from the viewpoint of ease of raw material synthesis and polymerization.

<Polyimide precursor>

The polyimide precursor contained in the resin composition for forming a porous film of the present invention contains a repeating unit represented by the following formula (1).

In the formula, X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from a diamine, and its structure contains a thermally decomposable functional group. R ₁ represents a hydrogen atom or an alkylene group having 1 to 5 carbon atoms. From the viewpoint of the ease of progress of the amide imidization reaction during heating, R _{1 is} preferably a hydrogen atom, a methyl group, and an ethyl group, and more preferably a hydrogen atom or a methyl group.

A ₁ and A ₂ are each independent, and are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms. From the viewpoint of liquid crystal alignment, A ₁ and A _{2 are} preferably hydrogen atoms or methyl groups.

<Tetracarboxylic acid derivative>

As the tetracarboxylic acid derivative component of the polymer having the structural unit of the above formula (1) contained in the resin composition for forming a porous membrane of the present invention, not only tetracarboxylic dianhydride but also can be used The tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester compound or tetracarboxylic acid dialkyl ester dihalide compound of the tetracarboxylic acid derivative.

As the tetracarboxylic dianhydride or its derivative, it is more preferable to use at least one selected from tetracarboxylic dianhydride and its derivative represented by the following formula (2).

X ₁ is a tetravalent organic group, and its structure is not particularly limited, but a tetravalent organic group having an alicyclic structure is preferred from the viewpoint of ease of porous membrane formation. Specific examples include the following formulas (X1-1) to (X1-10).

In formulas (X1-1) to (X1-4), R ₃ to R ₂₃ are each independent, and are a hydrogen atom, a halogen atom, a C 1-6 alkyl group, a C 2-6 alkenyl group, a carbon The alkynyl group having 2 to 6 or the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or the phenyl group may be the same or different. From the viewpoint of liquid crystal alignment, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom or a methyl group. As a specific structure of the formula (X1-1), a structure represented by the following formulas (X1-11) to (X1-16) may be mentioned. From the viewpoint of the ease of production of the porous membrane and the mechanical strength of the membrane, (X1-11) is particularly preferred.

As another specific example of X ₁ , the following structure may be mentioned.

<Specific diamine 1>

The diamine component used in the resin composition for forming a porous film of the present invention contains a diamine containing a thermally decomposable functional group in its structure (hereinafter also referred to as specific diamine 1). The diamine used to polymerize the polymer having the structure of the above formula (1) can be generalized by the following formula (3). The structure of Y ₁ is illustrated as follows.

A ₁ and A _{2 of the} above formula (3) also include preferred examples, and have the same definitions as A ₁ and A _{2 of the} above formula (1).

The structure of Y ₁ includes a structure represented by the following formula (4).

In the above formula (4), the D-type thermally decomposable functional group may be represented by benzyloxycarbonyl, 9- 茀 ylmethyloxycarbonyl, allyloxycarbonyl, t-butoxycarbonyl, etc. The carbamate-based organic group is excellent in t-butoxycarbonyl from the viewpoint of good efficiency of thermal desorption, which can desorb at a relatively low temperature, and emit harmless gas during desorption. From the standpoint of the ease of production of the porous membrane, it is preferable that it is directly connected to the benzene ring by the above formula (4).

As a specific example of Y _{1 including} the structure represented by the above formula (4), the following structure may be mentioned. (Y ₁ -1) (Y ₁ -6) (Y ₁ -7) (Y ₁ -8) having a plurality of t-butoxycarbonyl groups in one molecule is particularly preferred.

In the resin composition for forming a porous film used in the present invention, the concentration of the thermally decomposable functional group is important. The thermally decomposable functional group is preferably 0.5 mmol or more, preferably 1 mmol or more per 1 g of polymer coating film (the solvent has evaporated).

<Specific diamine 2>

The diamine component used in the resin composition for forming a porous membrane of the present invention is preferably a diamine containing a carboxylic acid group in its structure (hereinafter also referred to as specific diamine 2). By containing a carboxylic acid group, the temperature required for porous membrane formation can be reduced.

The specific diamine 2 system is generalized by the following formula.

The Y ₂ structure includes a structure represented by the following formula (6).

Z ₁ is an organic group having an aromatic ring having 6 to 30 carbon atoms, and n is an integer of 1 to 4.

As a preferable structure of the formula (2), the structures of the following formulas (7) to (11) can be mentioned.

In formula (7), m1 is an integer from 1 to 4; in formula (8), Z ₂ is a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) _2- , -CF ₂ -, -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO-, -OCO-, -CON (CH ₃ )-or -N (CH ₃ ) CO-, m2 and m3 each represent an integer of 0 to 4, and m2 + m3 represents an integer of 1 to 4; formula ( 9), m4 and m5 are each an integer of 1 to 5; in formula (10), Z ₃ is a linear or branched alkyl group having 1 to 5 carbon atoms, and m6 is an integer of 1 to 5; in formula (11) , Z ₄ is a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) _2- , -CF _2- , -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO-, -OCO-, -CON (CH ₃ )-or -N ( CH ₃ ) CO-, m7 is an integer from 1 to 4.

Preferably, in formula (7), m1 is an integer of 1 to 2; in formula (8), Z ₂ is a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) ₂ -, -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -COO-, or -OCO-, m2 and m3 are both integers of 1; In (11), Z ₄ is a single bond, -CH _2- , -O-, -CO-, -NH-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO- Or -OCO-, m7 is an integer from 1 to 2. Among them, the structure shown in formula (7) is particularly good.

As a specific example of the diamine compound (B), the following structure may be mentioned.

In formula (Y ₂ -10), X ₅ is a single bond, -CH _2- , -O-, -CO-, -NH-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO- or -OCO-; in formula (Y ₂ -11), X ₆ is a single bond, -CH _2- , -O-, -CO-, -NH-, -CONH-, -NHCO-,- CH ₂ O-, -OCH _2- , -COO- or -OCO-.

In addition, in the resin composition for forming a porous film used in the present invention, the concentration of the thermally decomposable functional group is the same, and the concentration of the above-mentioned carboxylic acid group is also important. The product of the amount of thermally decomposable functional groups and the amount of carboxylic acid present in 1 g of the total solids at which the residual solvent of the dried film is removed at 80 ° C. for 5 minutes is 5.7 × 10 ⁻⁶ mol ² or more, and becomes porous From the viewpoint of efficiency, it is preferable. The product of the amount of thermally decomposable functional groups and the amount of carboxylic acid present in 1 g of the total solids with the residual solvent of the dried film removed at 80 ° C. for 5 minutes is 4.1 × 10 ⁻⁶ mol ² or more, and becomes porous From the viewpoint of efficiency, it is preferable. Particularly good ones are 5.7 × 10 ^-6 mol ² or more.

<Other diamines>

In addition to the specific diamines 1 and 2 described above, the diamine component used in the resin composition for forming a porous film of the present invention may contain other diamines to the extent that the effect of the invention can be achieved. Although the structure of other diamines is not particularly limited, it can be generalized as follows, for example.

As a specific structure of Y ₃ , the following structures can be cited.

<Polyurea>

When the polymer compound used in the resin composition for forming a porous film of the present invention is polyurea, examples of the diisocyanate component of the raw material include aromatic diisocyanate and aliphatic diisocyanate. Preferred diisocyanate components are aromatic diisocyanate and aliphatic diisocyanate.

Here, the so-called aromatic diisocyanate refers to diisocyanate The R group of the cyanate ester structure (O = C = N-R-N = C = O) contains a structure having an aromatic ring. The aliphatic diisocyanate refers to a group in which the R group of the aforementioned isocyanate structure is composed of a cyclic or acyclic aliphatic structure.

Specific examples of the aromatic diisocyanate include o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, and toluene diisocyanate (for example, 2,4-diisocyanate Toluene cyanate), 1,4-diisocyanate-2-methoxybenzene, 2,5-diisocyanate xylenes, 2,2'-bis (4-diisocyanatophenyl) Propane, 4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanatodiphenyl ether, 4,4'-diisocyanatodiphenylsulfonate, 3,3'-diisocyanate Diphenyl cyanocyanate, 2,2'-diisocyanate benzophenone, etc. As the aromatic diisocyanate, preferably, toluene diisocyanate is used. Specific examples of the aliphatic diisocyanate include isophorone diisocyanate, hexamethylene diisocyanate, tetramethylethylene diisocyanate, and the like. The aliphatic diisocyanate preferably includes isophorone diisocyanate. Among them, isophorone diisocyanate and phenyltoluene 2,4-diisocyanate are preferred from the viewpoints of polymerization reactivity and voltage retention, and further, isophorone diisocyanate is obtained from availability, polymerization reactivity, From the viewpoint of voltage retention, it is better.

When the polymer compound used in the resin composition for forming a porous film of the present invention is polyurea, the type and requirements of the diamine component of the raw material are the same as the above-mentioned diamine compound.

<Production method of polyamide>

The polyamic acid ester of the polyimide precursor used in the present invention can be synthesized by the method (1), (2) or (3) shown below.

(1) Synthesized from polyamide

Polyamidates can be synthesized by esterifying polyamic acid obtained from tetracarboxylic dianhydride and diamine.

Specifically, it is possible to use polyamic acid and esterifying agent in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, 30 minutes to 24 hours, preferably 1 ~ 4 hours to carry out the reaction to synthesize.

As the esterifying agent, those that can be easily removed by purification are preferred, and examples include N, N-dimethylformamide dimethyl acetal and N, N-dimethylformamide diethyl Acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide dineopentylbutyl acetal, N, N-dimethylformamide di -t-butyl acetal, 1-methyl-3-p-tolyl triazene, 1-ethyl-3-p-tolyl triazene, 1-propyl-3-p-tolyl tri Nizene, 4- (4,6-dimethoxy-1,3,5-tri -2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents relative to 1 mole of the repeating unit of polyamide.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of the solubility of the polymer. One type may be used or two or more types may be mixed for use. From the standpoints that precipitation of the polymer is difficult and high molecular weight is easily obtained, the concentration during synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass.

(2) The synthesis by the reaction of tetracarboxylic acid diester dichloride and diamine

Polyamide can be synthesized with tetracarboxylic acid diester dichloride and diamine.

Specifically, by using tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C for 30 minutes to 24 hours , It is preferable to synthesize by reacting for 1 to 4 hours.

Among the aforementioned bases, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but in order to allow the reaction to proceed gently, pyridine is preferred. From the viewpoint of easy removal and easy to obtain a high molecular weight body, the addition amount of the base is preferably 2 to 4 times the molar amount relative to the tetracarboxylic acid diester dichloride.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of the monomer and the polymer, and these may be used alone or may be mixed Use 2 or more types. From the viewpoints that precipitation of the polymer is difficult and high molecular weight is easily obtained, the polymer concentration during synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the synthesis of the polyamide is preferably dehydrated as much as possible; in a nitrogen atmosphere, it is preferable to prevent the mixing of external air.

(3) Syntheses of polyamides from tetracarboxylic acid diesters and diamines

Polyamides can be synthesized by polycondensation of tetracarboxylic acid diesters and diamines.

Specifically, by using tetracarboxylic acid diester and diamine in the presence of a condensing agent, a base, and an organic solvent at 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C, for 30 minutes to 24 hours, Preferably, the reaction is carried out for synthesis in 3 to 15 hours.

Among the aforementioned condensing agents, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N , N'-carbonyldiimidazole, dimethoxy-1,3,5-tri Methyl morpholinium, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethylurea tetrafluoroborate, O- (benzotriazol-1-yl ) -N, N, N ', N'-tetramethylurea hexafluorophosphate, (2,3-dihydro-2-thio-3-benzoxazolyl) phosphonic acid diphenyl ester, etc. The addition amount of the condensing agent is preferably 2 to 3 times the molar amount relative to the tetracarboxylic acid diester.

Among the aforementioned bases, tertiary amines such as pyridine and triethylamine can be used. From the viewpoint of the amount that can be easily removed and the high molecular weight body that can be easily obtained, the addition amount of the base is preferably 2 to 4 times the molar amount of the diamine component.

In addition, in the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halide such as lithium chloride and lithium bromide is preferred. The amount of Lewis acid added is preferably 0 to 1.0 times the molar amount of the diamine component.

Among the above three methods for synthesizing polyamides, in order to obtain high molecular weight polyamides, the synthesis method of (1) or (2) above is particularly preferred.

As described above, the polyamide solution obtained by Injecting a lean solvent while stirring can cause the polymer to precipitate. After several precipitations and washing with a lean solvent, the purified polyamide powder can be obtained at room temperature or by heating and drying. Although the poor solvent is not particularly limited, water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. may be mentioned.

<Manufacturing method of polyamide>

The polyamic acid of the polyimide precursor used in the present invention can be synthesized by the method shown below.

Specifically, by using tetracarboxylic dianhydride and diamine in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, 30 minutes to 24 hours, preferably 1 ~ 12 hours for synthesis.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone from the viewpoint of the solubility of the monomer and the polymer These can be used alone or in combination of two or more. From the viewpoints that precipitation of the polymer is difficult and high molecular weight bodies are easily obtained, the concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 25% by mass.

As with the polyamic acid obtained above, by sufficiently stirring the reaction solution while injecting a lean solvent, the polymer can be precipitated and recovered. In addition, after performing several precipitations and washing with a lean solvent, purified polyamide powder can be obtained by drying at normal temperature or by heating. Although the poor solvent is not particularly limited, water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. may be mentioned.

<Manufacturing method of polyimide>

The polyimide used in the present invention can be produced by subjecting the aforementioned polyamic acid ester or polyamic acid to imidization. In the case of manufacturing polyimide from polyamic acid ester, an alkaline contact is added to the polyamic acid solution obtained by dissolving the aforementioned polyamic acid ester solution or polyamic acid ester resin powder in an organic solvent The chemical imidization of the medium is simple. The chemical imidization system is preferable because the imidization reaction proceeds at a relatively low temperature, and the molecular weight of the polymer does not easily decrease during the imidization process.

The chemical imidization can be carried out by stirring the polyamidate to be imidized in an organic solvent in the presence of an alkaline catalyst. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of slightly alkaline catalyst systems include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature during the amide imidization reaction is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C; the reaction time can be 1 to 100 hours. The amount of the alkaline catalyst is 0.5 to 30 mole times of the amide ester group, preferably 2 to 20 mole times. The acylation rate of the resulting polymer can be controlled by adjusting the catalyst amount, temperature, and reaction time. In the solution after the amide imidization reaction, the added catalyst and the like remain, so the amide imidized polymer obtained is recovered by the method described below and redissolved with an organic solvent to become the liquid crystal of the present invention The alignment agent is preferred.

In the case of manufacturing polyimide from polyamic acid, the polyamic acid solution obtained by the reaction of the diamine component and the tetracarboxylic dianhydride is added The chemical imidization with catalyst is simple. The chemical imidization system is preferable because the imidization reaction proceeds at a relatively low temperature, and the molecular weight of the polymer does not easily decrease during the imidization process.

The chemical imidization can be performed by stirring the polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst system include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferred because it has a moderate basicity to allow the reaction to proceed. In addition, examples of the acid anhydride system include acetic anhydride, trimellitic anhydride, and pyromellic anhydride. Among them, the use of acetic anhydride facilitates purification after completion of the reaction, which is preferable.

The temperature during the amide imidization reaction is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C; the reaction time can be 1 to 100 hours. The amount of alkaline catalyst is 0.5 to 30 mole times of the amide acid group, preferably 2 to 20 mole times; the amount of acid anhydride is 1 to 50 mole times of the amide acid group, preferably 3 to 30 mole times. The acylation rate of the resulting polymer can be controlled by adjusting the catalyst amount, temperature, and reaction time.

In the solution after the amidation reaction of the polyamic acid ester or the polyamic acid, since the added catalyst remains, the obtained amidated polymer is recovered by the following methods, and Re-dissolved in organic solvents to become the liquid crystal alignment agent of the present invention is preferred.

As described above, the solution of the polyamic acid can be precipitated by injecting a lean solvent while sufficiently stirring. After several precipitations and washing with lean solvent, purification can be obtained at room temperature or by heating and drying Polyamide powder.

Although the aforementioned poor solvent is not particularly limited, methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene and the like can be mentioned.

<Solvent>

The polymer compound containing a thermally decomposable functional group prepared as described above becomes a resin composition for forming a porous film together with an appropriately mixed solvent.

The solvent used in the resin composition for forming a porous film of the present invention is not particularly limited as long as it dissolves the polyimide precursor and polyimide described in the present invention (also referred to as a good solvent). Although specific examples of good solvents are given below, they are not limited to these examples.

For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, di Methyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone or 4-hydroxy-4-methyl-2-pentanone Wait. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are preferably used.

In addition, when the polyimide precursor and the polyimide described in the present invention have high solubility in a solvent, the solvent represented by the following formula [D-1] to formula [D-3] is used good.

In formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms; in formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms; in formula [D-3], D ³ It represents an alkyl group having 1 to 4 carbon atoms.

The good solvent in the liquid crystal alignment agent is preferably 20 to 99% by mass of the entire solvent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

As long as the liquid crystal alignment agent does not impair the effects of the present invention, it may contain a solvent (also referred to as a poor solvent) that enhances the coating properties or surface smoothness of the liquid crystal alignment film when the liquid crystal alignment agent is applied. These poor solvents are preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent. Among them, 10 to 80% by mass is preferable. It is more preferably 20 to 70% by mass.

Although specific examples of the poor solvent can be given below, they are not limited to these examples. For example, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl- 1-butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2- Amyl alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol Alcohol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2 -Ethyl-1,3-hexanediol, dipropyl ether, di Butyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethyl ether Ethylene glycol diethyl ether, diethylene glycol methyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethyl Oxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate , Ethyl carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol , Diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol di Methyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethyl ether Ethylene glycol monoethyl ether acetate, diethylene glycol mono Butyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, lactic acid Methyl ester, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, 3-ethoxy Methyl ethyl propionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3-methoxypropionate Butyl acid ester, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, or solvents represented by the aforementioned formula [D-1] to formula [D-3], etc.

Among them, 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether are used Ether acetate or dipropylene glycol dimethyl ether is preferred.

The resin composition for forming a porous film used in the present invention can also introduce a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group, or a cyclocarbonate group as another component, and has , A crosslinkable compound of at least one substituent in the group consisting of hydroxyalkyl and lower alkoxyalkyl, or a crosslinkable compound having a polymerizable unsaturated bond.

Examples of the crosslinkable compound having an epoxy group or an isocyanate group include bisphenol acetone epoxypropyl ether, phenol novolak epoxy resin, cresol novolak epoxy resin, and triglycidyl isotrimer. Cyanate, tetrapropyleneglycidyl diphenyl ester, tetraglycidyl-m-xylenediamine, tetraglycidyl-1,3-bis (aminoethyl) cyclohexane, tetraphenyl Glycidoxypropyl ether ethane, triphenylglycidoxypropyl ether ethane, bisphenol hexafluoroacetone diglycidyl ether, 1,3-bis (1- (2,3-epoxypropyloxy ) -1-trifluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-epoxypropoxy) octafluorobiphenyl, triglycidoxy-p -Aminophenol, tetraglycidoxy m-xylenediamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4- (2,3-epoxypropoxy) phenyl) ethyl) phenyl) propane or 1,3-bis (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1- (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol, etc. .

The crosslinkable compound having an oxetane group is a compound having at least two oxetane groups represented by the following formula [4A].

Specifically, a crosslinkable compound represented by formula [4a] to formula [4k] disclosed in pages 58 to 59 of International Publication WO2011 / 132751 (published on 2011.10.27) can be given.

The crosslinkable compound having a cyclic carbonate group is a crosslinkable compound having at least two cyclic carbonate groups represented by the following formula [5A].

Specifically, the cross-linkable compounds represented by Formula [5-1] to Formula [5-42] disclosed in International Publication WO2012 / 014898 (2012.2.2 published) pages 76 to 82 can be mentioned.

Examples of the crosslinkable compound having at least one substituent selected from the group consisting of hydroxy and alkoxy groups include amine-based resins having hydroxy or alkoxy groups, such as melamine resins, urea resins, and guanidine. Amine resin, glycoluril-formaldehyde resin, succinylamide-formaldehyde resin or ethylene urea-formaldehyde resin, etc. Specifically, a melamine derivative, benzoguanidine which has a hydrogen atom of an amine group replaced by a methylol group or an alkoxymethyl group or both can be used Derivatives or glycolurils. This melamine derivative or benzoguanidine Derivatives can also exist as dimers or trimers. Each of these three Those having an average of 3 or more and 6 or less methylol groups or alkoxymethyl groups in the ring are preferred.

As the above melamine derivative or benzoguanidine Examples of derivatives include three per commercial product. MX-750 with an average of 3.7 methoxymethyl rings, three per MX-750 MW-30 (above, manufactured by Sanwa Chemical Co., Ltd.) or CYMEL300, 301, 303, 350, 370, 771, 325, 327, 703, 712 and other methoxymethyl groups substituted with an average of 5.8 methoxymethyl groups Melamine based, methoxymethylated butoxymethylated melamine such as CYMEL235, 236, 238, 212, 253, 254, butoxymethylated melamine such as CYMEL506, 508, containing carboxyl group like CYMEL1141 Methoxymethylated isobutoxymethylated melamine, methoxymethylated ethoxymethylated benzoguanidine like CYMEL1123 , Methoxymethylated butoxymethylated benzoguanidine like CYMEL1123-10 , CYMEL1128, butoxymethylated benzoguanidine , CYMEL1125-80 and the like containing carboxymethyloxymethylated ethoxymethylated benzoguanidine (Above, manufactured by Mitsui CYANAMID). Examples of glycolurils include butoxymethylated glycolurils such as CYMEL1170, hydroxymethylated glycolurils such as CYMEL1172, and methoxyhydroxymethylated glycolurils such as POWERLINK1174. .

Examples of benzene or phenolic compounds having a hydroxyl group or an alkoxy group include 1,3,5-ginseng (methoxymethyl) benzene and 1,2,4-ginseng (isopropoxymethyl) benzene , 1,4-bis (sec-butoxymethyl) benzene or 2,6-dihydroxymethyl-p-tert-butanol.

More specifically, the formulae [6-1] to [6-48] disclosed in pages 62 to 66 of International Publication No. WO2011 / 132751 (published on 2011.10.27) can be cited. Crosslinkable compounds.

Examples of the crosslinkable compound having a polymerizable unsaturated bond include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, Cross-linkable compound with 3 polymerizable unsaturated groups in the molecule of tri (meth) acryloxyethoxytrimethylolpropane or glycerin polyglycidyl ether poly (meth) acrylate etc. ; Furthermore, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate , Propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide bisphenol A Type di (meth) acrylate, propylene oxide bisphenol type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerol di (meth) acrylate, pentaerythritol di (Meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, phthalic acid A cross-linkable compound having two polymerizable unsaturated groups in the molecule of diglycidyl diacrylate (meth) acrylate or hydroxytrimethyl acetate neopentyl glycol di (meth) acrylate; etc. -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (methyl) Acrylate, 2- (meth) acryloxy-2-hydroxypropylphthalate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerol mono (meth) acrylate, 2 -A cross-linkable compound having one polymerizable unsaturated group in the molecule of (meth) acryloyloxyethyl phosphate, N-hydroxymethyl (meth) acrylamide, etc.

Furthermore, the compound represented by following formula [7A] can also be used.

(In formula [7A], E ₁ represents a group selected from the group consisting of cyclohexane ring, bicyclohexane ring, benzene ring, biphenyl ring, terphenyl ring, naphthalene ring, stilbene ring, anthracene ring or phenanthrene ring Group, E ₂ represents a group selected from the following formula [7a] or formula [7b], and n represents an integer of 1-4).

The above is an example of a crosslinkable compound, and is not limited to these. In addition, the crosslinkable compound used in the liquid crystal alignment agent of the present invention may be one kind, or two or more kinds may be combined.

In the liquid crystal alignment agent of the present invention, the content of the crosslinkable compound is preferably 0.1 to 150 parts by mass relative to 100 parts by mass of the entire polymer component. Among them, in order to perform the crosslinking reaction and express the target effect, it is preferably 0.1 to 100 parts by mass relative to 100 parts by mass of the polymer component. The better is 1 ~ 50 parts by mass.

As long as the liquid crystal alignment agent of the present invention does not impair the effects of the present invention, a compound that enhances the film thickness uniformity or surface smoothness of the liquid crystal alignment film when coating the liquid crystal alignment agent can be used.

Examples of the compound that improves the film thickness uniformity or surface smoothness of the liquid crystal alignment film include fluorine-based surfactants, polysiloxane-based surfactants, and nonionic surfactants.

More specifically, for example, F-TOP EF301, EF303, EF352 (above, manufactured by TOHKEM PRODUCTS), MEGAFAC F171, F173, R-30 (above, manufactured by Dainippon Ink Company), FLUORAD FC430, FC431 (above) , Manufactured by Sumitomo 3M Company), ASAHIGUARD AG710, SURFLON S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.), etc.

The amount of the surfactant used is preferably 0.01 to 2 parts by mass, and more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of all polymer components contained in the liquid crystal alignment agent.

Furthermore, in the liquid crystal alignment agent, as a compound that promotes the charge movement in the liquid crystal alignment film and promotes the decharge of the element, it is possible to add the compounds disclosed in International Publication WO2011 / 132751 (published on 2011.10.27), pages 69 to 73. The nitrogen-containing heterocyclic amine compound represented by formula [M1] to formula [M156]. Although it does not matter that the amine compound is directly added to the liquid crystal aligning agent, it is preferably prepared after adding a solution having a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. The solvent is not particularly limited as long as it can dissolve the specific polymer (A).

In the liquid crystal alignment agent of the present invention, in addition to the above-mentioned poor solvent, crosslinkable compound, resin coating or compound that enhances the film thickness uniformity or surface smoothness of the liquid crystal alignment film and the compound that promotes decharge, as long as it is not Within the scope of detracting from the effect of the present invention, the A polymer other than the loaded polymer, a silane coupling agent for the purpose of improving the adhesion between the alignment film and the substrate, and further to make the imidization of the polyimide precursor by heating when the coating film is fired. Promoters such as amide imidization for efficient purposes.

For the resin composition for forming a porous film used in the present invention, the concentration of the thermally decomposable functional group is important. For example, as a polymer coating film obtained by removing the entire solid content of the residual solvent of the dried film at 80 ° C for 5 minutes, it is desirable that the thermally decomposable functional group contains 0.5 mmol or more per 1 g, preferably 1 mmol or more.

In addition, the concentration of the above-mentioned carboxylic acid group is also important. As a polymer coating film formed by removing the solid content of the residual solvent of the dried film at 80 ° C for 5 minutes, it is desirable to contain 2 mmol or more per 1 g, preferably It is 2.5 mmol or more.

<Film formation step>

By using the resin composition for forming a porous membrane of the present invention, a porous membrane can be formed. An example of the specific flow is as follows.

First, there is a film forming step of forming a polymer coating film containing a thermally decomposable functional group that decomposes due to heat and generates gas.

The film forming step is a step of forming a coating film by applying a resin composition for forming a porous film for forming a polymer coating film containing a thermally decomposable functional group that decomposes and generates gas due to heat, and also It may not include a drying step. That is, after the resin composition for forming a porous film is applied, the high-temperature heating may be performed immediately to perform the porosification step.

In addition, the film forming step may include a step of drying the coating film. The step of drying the coating film can be dried naturally or by heating the coating film. The heating in the drying step is different from the porosification step described below. It is only necessary to remove at least a part of the solvent contained in the resin composition, and it cannot be heated until the solvent is completely removed. In addition, it must be carried out under conditions that do not cause thermal decomposition of the thermally decomposable functional group, for example, it means that the temperature is less than 100 ° C.

Although the coating method used in the coating step is not particularly limited, the industry generally uses screen printing, offset printing, flexographic printing, inkjet, and the like. As another coating method, there are a dip coater, a roll coater, a slit coater, a spin coater, etc., and these can also be used according to the purpose.

The drying step after applying the porous film forming resin composition on the substrate can be carried out by heating means such as a hot plate at 40 ° C to 150 ° C, preferably 60 ° C to 130 ° C Evaporate to form a coating film. The thickness of the coating film formed after firing is preferably 0.5 μm to 500 μm, more preferably 5 μm to 100 μm.

<Porous step>

Next, there is provided a step of making a porous film by heating the polymer coating film to decompose the thermally decomposable functional group and making a porous film.

The porous step is a step of thermally decomposing the thermally decomposable functional group contained in the polymer coating film by heating the polymer coating film, and is thermally decomposed and desorbed (degassed) (degassed) by the thermally decomposable functional group Gas step) to generate gas and form voids in the polymer coated membrane to make a porous membrane Step. Although the details of this porosification step will be described later, the heating temperature may be a temperature at which the thermally decomposable functional group can be thermally decomposed, and it is 100 ° C or higher, preferably 150 ° C or higher.

From the degassing step to the porosification step, for example, it is important that degassing does not occur in the above-mentioned drying step or the subsequent steps, and it is preferable that all degassing steps are ended in the porosification step.

<Porous membrane>

Like the porous membrane produced above, it has a porous structure having long columnar voids in the thickness direction of the membrane. Although the size of the voids of the porous structure varies according to the film thickness, it has a size of about 1 to 10 μm wide and about 1 to 30 μm high.

By the above-mentioned porosification step, the haze value of the film after the drying step is set to 0%, and it becomes a cloudy film with a haze value of 10 to 85%.

<Use of porous membrane>

The porous membrane manufactured by using the resin composition for forming a porous membrane of the present invention has excellent heat resistance, mechanical properties, and chemical resistance, and has a low dielectric constant due to a large number of voids in the membrane , Can be expected as Low-k material applications. In addition, the air existing in the voids can be easily replaced with liquid, and it is also expected to be applied to battery separators and electrolytic capacitor separators. In addition, because the membrane contains acidic groups such as carboxylic acid or sulfonic acid, it can also be expected to be used in fuel cells because of its proton transport capability. The application of solid electrolyte or binder for positive and negative electrodes. In addition, a water-repellent functional group such as a fluorine group or an alkyl side chain may be introduced, and high performance and durability when used as an electret can be expected. In addition, it can also be expected to be applied to soundproof materials or heat insulating materials.

[Example]

Although the following examples illustrate the present invention in more detail, the present invention is not limited thereto.

In the following, the abbreviations of the compounds used in the present examples and comparative examples and the measurement methods of each characteristic are as follows.

NMP: N-methyl-2-pyrrolidone

DA-1: Refer to the following formula (DA-1)

DA-2: 4,4 '- diamino diphenyl methane

DA-3: Refer to the following formula (DA-3)

DA-4: Refer to the following formula (DA-4)

DA-5: Refer to the following formula (DA-5)

DA-6: Refer to the following formula (DA-6)

DA-7: 3,5-diaminobenzoic acid

DA-8: Refer to the following formula (DA-8)

DA-9: Refer to the following formula (DA-9)

DAH-1: cyclobutane tetracarboxylic dianhydride

DAH-2: Refer to the following formula (DAH-2)

DAH-3: pyromellitic dianhydride

DAH-4: Refer to the following formula (DAH-4)

DI-1: Refer to the following formula (DI-1)

The measurement methods of each characteristic used in the examples are as follows Column.

[Measurement of haze value]

Using a glass substrate with a transparent electrode without a thin film as a reference, the film coated on the glass substrate with a transparent electrode was measured for haze with a spectrophotometer (TC-1800H) (manufactured by Tokyo Denshi) Degree value.

[Measurement of film thickness]

The height difference caused by cutting a part of the thin film coated on the glass substrate with a transparent electrode to the surface of the substrate using an interference microscope (ContourGT-K) (manufactured by BRUKER AXS Co., Ltd.) measurement was used to measure the thickness of the thin film. Film thickness.

[Determination of Dielectric Constant]

After an aluminum electrode with a surface area of 4 mm ^{2 was} vapor-deposited on a thin film coated on a glass substrate with a transparent electrode, LCR MAKER (ZM2354) (manufactured by NF Circuit Design BLOCK Co., Ltd.) was used and measured under the conditions of 1V1KHz Dielectric constant.

(Synthesis Example 1)

13.05 g (55 mmol) of DA-1 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 37 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 10.25 g (52.25 mmol) of DAH-1 was added, followed by NMP to make the solid form The concentration became 25% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA-1). After confirming the viscosity at 25 ° C of this polyamide acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 4.32 Pa‧s.

(Synthesis Example 2)

Take DA-1 7.12g (30mmol) and DA-2 6.01g (30mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding NMP 37g, stir while feeding nitrogen It dissolves. While stirring this diamine solution, 11.18 g (57 mmol) of DAH-1 was added, followed by addition of NMP so that the solid content concentration became 25% by mass, and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA-2 ). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 5.16 Pa‧s.

(Synthesis Example 3)

12.01 g (60 mmol) of DA-2 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 35 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 10.35 g (52.8 mmol) of DAH-1 was added, followed by addition of NMP so that the solid content concentration became 25% by mass, and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 3). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 4.55 Pa‧s.

(Synthesis Example 4)

11.87 g (50 mmol) of DA-1 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 40 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 12.19 g (48.75 mmol) of DAH-2 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirred at 60 ° C. for 48 hours to obtain a polyamic acid solution (PAA- 4). After confirming the viscosity of this polyamide solution at 25 ° C with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 4.13 Pa‧s.

(Synthesis Example 5)

12.58 g (53 mmol) of DA-1 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 58 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 10.98 g (50.35 mmol) of DAH-3 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirring at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 5). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 9.66 Pa‧s.

(Synthesis Example 6)

10.68 g (45 mmol) of DA-1 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 43 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 12.58 g (42.75 mmol) of DAH-4 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirring at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 6). Confirm this polymerization with an E-type viscometer (manufactured by Toki Industries) The viscosity of the amino acid solution at 25 ° C is 7.88 Pa‧s.

(Synthesis Example 7)

Take DA-1 6.53g (27.5mmol) and DA-3 6.58g (22.5mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and add 44g of NMP, then stir while feeding nitrogen And dissolve it. While stirring this diamine solution, 9.31 g (47.5 mmol) of DAH-1 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirring at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 7). After confirming the viscosity of this polyamic acid solution at 25 ° C with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 4.18 Pa‧s.

(Synthesis Example 8)

Take DA-1 6.80g (28.67mmol) and DA-4 7.52g (18.33mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 40g of NMP, stir while feeding nitrogen And dissolve it. While stirring this diamine solution, 8.76 g (44.65 mmol) of DAH-1 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirring at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 8). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 4.36 Pa‧s.

(Synthesis Example 9)

Take DAH-1 9.81g (50mmol) into the attached stirring device and introduce nitrogen After adding 46 g of NMP to a 100 mL four-necked flask in a tube, it was stirred and dissolved while feeding nitrogen gas. While stirring this acid disregard solution, DA-1 6.64g (28mmol) and DA-5 7.25g (20mmol) were added, followed by NMP to make the solid content concentration 25% by mass, and stirred at room temperature for 24 hours. A polyamide acid solution (PAA-9) was obtained. After confirming the viscosity at 25 ℃ of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 10.49 Pa‧s.

(Synthesis Example 10)

Take DA-1 12.79g (53.9mmol) and DA-6 0.38g (1.1mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, add 40g of NMP, and stir while feeding nitrogen And dissolve it. While stirring this diamine solution, 10.25 g (52.25 mmol) of DAH-1 was added, and then NMP was added to make the solid concentration 25% by mass, and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 12). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 5.42 Pa‧s.

(Synthesis Example 11)

Take DA-1 5.58g (23.5mmol) and DA-7 4.03g (26.5mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding NMP 45g, stir while feeding nitrogen And dissolve it. While stirring this diamine solution, 9.41 g (48 mmol) of DAH-1 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirred at room temperature After stirring for 24 hours, a polyamic acid solution (PAA-13) was obtained. After confirming the viscosity at 25 ° C of this polyamide acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 4.74 Pa‧s.

(Synthesis Example 12)

10.65 g (70 mmol) of DA-7 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 56 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 13.04 g (66.5 mmol) of DAH-1 was added, followed by addition of NMP so that the solid content concentration became 25% by mass, and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 14). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 7.40 Pa‧s.

(Synthesis Example 13)

17.56g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was put into a 50ml sample tube placed in a stirrer, and 15.89g of the polyamic acid solution (PAA-14) obtained in Synthesis Example 14 was added and The mixture was stirred and mixed at room temperature for 24 hours to obtain a polyamic acid solution (PAA-15).

(Synthesis Example 14)

17.81 g (32 mmol) of DA-8 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 41 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.90 g (30.08 mmol) of DAH-1 was added, followed by NMP to make the solid form The concentration became 25% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA-19). After confirming the viscosity at 25 ° C of this polyamic acid solution with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 10.24 Pa‧s.

(Synthesis Example 15)

Take DA-8 12.25g (22mmol) and DA-7 3.35g (22mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and add 38g of NMP, stirring while feeding nitrogen It dissolves. While stirring this diamine solution, 8.24 g (42.02 mmol) of DAH-1 was added, and then NMP was added to make the solid content concentration 25% by mass, and stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA- 20). After confirming the viscosity of this polyamide solution at 25 ° C with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 7.28 Pa‧s.

(Synthesis Example 16)

Take DA-2 5.61g (28mmol) and DA-9 8.16g (28mmol) into a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 37g of NMP, stir while feeding nitrogen It dissolves. While stirring this diamine solution, 9.88 g (50.4 mmol) of DAH-1 was added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirring at room temperature for 24 hours to obtain a polyamic acid solution (PAA- twenty two). After confirming the viscosity at 25 ° C of this polyamide acid solution with an E-type viscometer (manufactured by Toki Industries Co., Ltd.), it was 5.76 Pa‧s.

(Synthesis Example 17)

17.26 g (31 mmol) of DA-8 was put into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and after adding 40 g of NMP, it was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 3.34 g (17.05 mmol) of DAH-1 and 2.85 g (12.4 mmol) of DI-1 were added, followed by addition of NMP to make the solid content concentration 25% by mass, and stirred at 60 ° C. for 24 hours A polyamide / polyurea copolymer solution (PAA / PU-1) was obtained. After confirming the viscosity at 25 ° C of the polyamide / polyurea copolymer solution with an E-type viscometer (manufactured by Toki Industries, Ltd.), it was 2.19 Pa‧s.

(Example 1)

The polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing in a hot-air circulation oven at a temperature of 250 ° C. for 5 minutes, a hazy film with a haze value of 81% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 2)

The polyamic acid solution (PAA-2) obtained in Synthesis Example 2 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing in a hot-air circulation type oven at a temperature of 230 ° C. for 5 minutes, a hazy film with a haze value of 73% was obtained. After observing the fired film with a microscope, confirm It is a porous membrane with uniform air holes in the membrane.

After measuring the relative permittivity of this porous membrane, it was 3.85 Pa‧s.

The porous film and the glass substrate with a transparent electrode on the base were made into FIB cross-sectional data and observed by SEM. As a result, it was confirmed that a porous structure with a diameter of about 10 μm in the membrane (see FIG. 1 (a)), and that there were pores of several 100 nm on the wall surface within the pores (see FIG. 1 (b)).

(Example 3)

The polyamic acid solution (PAA-2) obtained in Synthesis Example 2 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing in a hot-air circulation oven at a temperature of 250 ° C. for 5 minutes, a hazy film with a haze value of 81% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

After measuring the relative permittivity of this porous membrane, it was 2.10 Pa‧s.

The porous film and the glass substrate with a transparent electrode on the base were made into FIB cross-sectional data and observed by SEM. As a result, it was confirmed that a porous structure with a width of about 10 μm and a height of about 30 μm in the membrane (see FIG. 2 (a)), and the presence of pores of several 100 nm on the wall surface inside the pore (see FIG. 2 (b)).

(Comparative example 1)

The polyamic acid solution (PAA-3) obtained in Synthesis Example 3 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing in a hot air circulating oven at a temperature of 250 ° C. for 5 minutes, a transparent film with a haze value of 0% was obtained. After observing this fired film with a microscope, it was confirmed that there were no air holes in the film.

(Comparative example 2)

25.3 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 was put into a 50 mL sample tube that had been placed in a stirrer, and DA-1 2.62 g was added, and stirred at room temperature for 24 hours to dissolve. From the fact that the viscosity did not change around 24 hours, it can be known that DA-1 did not react with polyamide and only dissolved in the solvent. This DA-1 dissolved polyamide solution was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm. Thereafter, after firing in a hot air circulating oven at a temperature of 250 ° C. for 5 minutes, a transparent film with a haze value of 0% was obtained. After observing this fired film with a microscope, it was confirmed that there were no air holes in the film.

(Example 4)

The polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Then, after firing on a hot plate with a temperature of 190 ° C for 5 minutes, a haze value of 80% was obtained Cloudy film. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 5)

The polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm under the same conditions as in Example 3, and fired on a hot plate at a temperature of 190 ° C After 5 minutes, a hazy film with a haze value of 80% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 6)

The polyamic acid solution (PAA-2) obtained in Synthesis Example 2 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Then, after firing on a hot plate at a temperature of 190 ° C for 5 minutes, a white turbid film with a haze value of 79% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 7)

The polyamic acid solution (PAA-2) obtained in Synthesis Example 2 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm under the same conditions as in Example 5 and fired on a hot plate at a temperature of 190 ° C After 5 minutes, a hazy film with a haze value of 80% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 8)

The polyamic acid solution (PAA-4) obtained in Synthesis Example 4 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 210 ° C. for 5 minutes, a hazy film with a haze value of 82% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 9)

The polyamic acid solution (PAA-5) obtained in Synthesis Example 5 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 250 ° C. for 5 minutes, a hazy film with a haze value of 51% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 10)

The polyamic acid solution (PAA-6) obtained in Synthesis Example 6 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 220 ° C. for 5 minutes, a hazy film with a haze value of 78% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 11)

The polyamic acid solution (PAA-7) obtained in Synthesis Example 7 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 210 ° C. for 5 minutes, a hazy film with a haze value of 83% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 12)

The polyamic acid solution (PAA-8) obtained in Synthesis Example 8 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Then, after firing on a hot plate at a temperature of 250 ° C. for 5 minutes, a hazy film with a haze value of 53% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 13)

The polyamic acid solution (PAA-9) obtained in Synthesis Example 9 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 230 ° C. for 5 minutes, a hazy film with a haze value of 81% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 14)

The polyamic acid solution (PAA-12) obtained in Synthesis Example 10 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 200 ° C for 5 minutes, a hazy film with a haze value of 72% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 15)

The polyamic acid solution (PAA-13) obtained in Synthesis Example 11 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Then, after firing on a hot plate at a temperature of 170 ° C. for 5 minutes, a hazy film with a haze value of 80% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 16)

Take 35.13 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 into a 50 mL sample tube that has been placed in a stirrer, and add 0.6811 g of p-toluenesulfonic acid monohydrate and stir and mix at room temperature 24 hour.

This polyamide solution was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm. Thereafter, heating at a temperature of 180 ° C After firing on the plate for 5 minutes, a hazy film with a haze value of 84% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 17)

The polyamic acid solution (PAA-15) obtained in Synthesis Example 13 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 170 ° C. for 5 minutes, a hazy film with a haze value of 77% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 18)

The polyamic acid solution (PAA-19) obtained in Synthesis Example 14 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 180 ° C. for 5 minutes, a hazy film with a haze value of 82% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 19)

The polyamic acid solution (PAA-20) obtained in Synthesis Example 15 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, in Wen After firing on a hot plate at 155 ° C for 5 minutes, a hazy film with a haze value of 83% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 20)

The polyamic acid solution (PAA-22) obtained in Synthesis Example 16 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 20 μm membrane. Thereafter, after firing on a hot plate at a temperature of 170 ° C. for 5 minutes, a hazy film with a haze value of 84% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Example 21)

The polyamic acid / polyurea copolymerization solution (PAA / PU-1) obtained in Synthesis Example 17 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes To obtain a transparent film with a thickness of 20 μm. Thereafter, after firing for 5 minutes on a hot plate at a temperature of 190 ° C, a hazy film with a haze value of 83% was obtained. After observing this fired film with a microscope, it was confirmed to be a porous film having uniform air holes in the film.

(Test Example 1)

12.67 g of the polyamic acid solution (PAA-20) obtained in Synthesis Example 15 was put into a 50 mL sample tube that had been put into a stirrer, and 19.01 g of NMP was added, and stirred at room temperature for 24 hours to obtain polyamidoamine Acid solution (PAA-21). Take E Type viscometer (manufactured by Toki Industries Co., Ltd.) confirms the viscosity of this polyamide acid solution at a temperature of 25 ° C, which is 71.7mPa‧s.

This PAA-21 was spin-coated on a glass substrate with a transparent electrode having a thickness of 1.1 mm at various rotation numbers, and dried on a hot plate at a temperature of 80 ° C. for 5 minutes to obtain a transparent film with a thickness of 440 to 1220 nm. Thereafter, firing was performed on a hot plate at a temperature of 300 ° C for 5 minutes. The results of haze value measurement and microscopic observation of the film are summarized in Table 1.

As a result, it has been known that the porous membrane resin composition having a viscosity of 71.7 mPa‧s can be obtained as a polymer coating membrane with a film thickness of 550 to 1220 nm, but at 440 to 490 nm. The following will not become porous. In addition, this test is only a test at a specific viscosity, does not mean that the porous can only be 550 ~ 1220nm polymer coating film.

Claims (7)

A resin composition for forming a porous film, characterized by comprising: a polymer compound having a thermally decomposable functional group that decomposes due to heat and generates gas, and the polymer compound includes a polymer or copolymer, and the polymer or copolymer The substance contains a polyimide precursor obtained by reacting a tetracarboxylic acid derivative with a diamine component and a polyimide obtained by reacting the imidate, or a diisocyanate and a diamine component At least one of the groups consisting of polyureas, and any one of the polymers or copolymers containing at least one of the foregoing is obtained by polymerizing or copolymerizing the monomer having the thermally decomposable functional group, The aforementioned thermally decomposable functional group is t-butoxycarbonyl (Boc group). The resin composition for forming a porous membrane according to claim 1, wherein the resin composition for forming a porous membrane includes a polyimide precursor obtained by reacting a tetracarboxylic acid derivative with a diamine component and its amide imide Polyimide obtained by chemical conversion, and the aforementioned mono-system diamine compound having a thermally decomposable functional group. The resin composition for forming a porous film according to claim 2, wherein the diamine component includes the diamine having the thermally decomposable functional group and other diamine compounds. The resin composition for forming a porous membrane according to any one of claims 1 to 3, wherein the resin composition for forming a porous membrane contains a strong acid. The resin composition for forming a porous film according to any one of claims 1 to 3, wherein 1 g of the resin composition contains 0.5 mmol or more of t-butoxycarbonyl group (Boc group). The resin composition for forming a porous membrane according to any one of claims 1 to 3, wherein 1 g of the resin composition contains a total of 2 mmol or more of acidic functional groups and acidic compounds. A porous membrane, which is obtained from the resin composition for forming a porous membrane according to claims 1 to 6, characterized by including voids, the voids containing gas generated by thermal decomposition of the aforementioned thermally decomposable functional group Or replace the air of the gas.