Aqueous polyimide precursor solution composition and method for producing aqueous polyimide precursor solution composition

Abstract

An aqueous polyimide precursor solution composition in which a polyamic acid which is formed by the reaction of a tetracarboxylic acid component and a diamine component, and contains a repeating unit represented by the following formula (1), is dissolved in an aqueous solvent together with an imidazole in an amount of 1.6 mole or more per mole of the tetracarboxylic acid component of the polyamic acid, in which the aqueous polyimide precursor solution composition contains no organic solvent, and the polyamic acid has an inherent viscosity of 0.2 or more.

What is claimed is: 
     
         1 . An aqueous polyimide precursor solution composition, wherein
 a polyamic acid, which is formed by the reaction of a tetracarboxylic acid component and a diamine component, and consists of a repeating unit represented by the following formula (1), is dissolved in an aqueous solvent together with an imidazole in an amount of 1.6 mole or more per mole of the tetracarboxylic acid component of the polyamic acid,   
       wherein
 the aqueous polyimide precursor solution composition contains no organic solvent, and 
 
       
         
           
           
               
               
           
         
         the polyamic acid has an inherent viscosity of 0.2 or more. 
       
       wherein
 A represents at least one group selected from the group consisting of a tetravalent group of an aromatic tetracarboxylic acid containing no fluorine group from which carboxyl groups have been removed, a tetravalent group of an aliphatic tetracarboxylic acid from which carboxyl groups have been removed, and a tetravalent group of an aromatic tetracarboxylic acid containing a fluorine group from which carboxyl groups have been removed, and 
 B represents at least one group selected from the group consisting of a divalent group of an aromatic diamine containing no fluorine group and having a solubility in water at 25° C. of 0.1 g/L or more from which amino groups have been removed, a divalent group of an aliphatic diamine having a molecular weight of 500 or less from which amino groups have been removed, and a divalent group of an aromatic diamine containing a fluorine group, from which amino groups have been removed, with the proviso that 
 more than 50 mol % of A is a tetravalent group of an aromatic tetracarboxylic acid containing no fluorine group from which carboxyl groups have been removed, and less than 50 mol %, including 0 mol %, of A is a tetravalent group of an aliphatic tetracarboxylic acid from which carboxyl groups have been removed, and/or a tetravalent group of an aromatic tetracarboxylic acid containing a fluorine group from which carboxyl groups have been removed, and 
 more than 50 mol % of B is a divalent group of an aromatic diamine containing no fluorine group and having a solubility in water at 25° C. of 0.1 g/L or more from which amino groups have been removed, and less than 50 mol %, including 0 mol %, of B is a divalent group of an aliphatic diamine having a molecular weight of 500 or less from which amino groups have been removed, and/or a divalent group of an aromatic diamine containing a fluorine group from which amino groups have been removed, and 
 a combination of only a tetravalent group (A) of an aromatic tetracarboxylic acid containing no fluorine group from which carboxyl groups have been removed, and only a divalent group (B) of an aromatic diamine containing no fluorine group from which amino groups have been removed, is excluded. 
 
     
     
         2 . The aqueous polyimide precursor solution composition according to  claim 1 , wherein the imidazole is selected from the group consisting of 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, and 1-methyl-4-ethylimidazole. 
     
     
         3 . A method for producing an electrode, comprising:
 producing an electrode mixture paste by mixing the aqueous polyimide precursor solution composition according to  claim 1  with an electrode active material;   applying the electrode mixture paste onto a current collector; and then   heating the electrode mixture paste to remove a solvent and effect imidization.