Particle-dispersed polyimide precursor solution, method for producing porous polyimide film, and porous polyimide film

1. A particle-dispersed polyimide precursor solution, comprising:

a polyimide precursor consisting of a polymer of a tetracarboxylic dianhydride and a diamine containing a fluorene-based diamine having a fluorene skeleton;

particles; and

an aqueous solvent containing water,

wherein a total content of a structure derived from the fluorene-based diamine is 1% by mass or more and 50% by mass or less with respect to the particles.

2. The particle-dispersed polyimide precursor solution according to claim 1 , wherein the polyimide precursor is a polyimide precursor having a unit represented by the following Formula (I):

wherein A represents a tetravalent organic group, and B represents a divalent organic group represented by the following Formula (B1) derived from the fluorene-based diamine, and

wherein R 1 to R 4 each independently represent a halogeno group, an alkyl group, an alkoxy group, or an aryl group, a to d each independently represent an integer of 0 to 4, and X A is a single bond or a divalent organic group.

3. The particle-dispersed polyimide precursor solution according to claim 2 , wherein the total content of the structure derived from the fluorene-based diamine is 40% by mass or more and 60% by mass or less with respect to a total amount of the polyimide precursor.

4. The particle-dispersed polyimide precursor solution according to claim 3 , wherein the total content of the structure derived from the fluorene-based diamine is 45% by mass or more and 60% by mass or less with respect to the total amount of the polyimide precursor.

5. The particle-dispersed polyimide precursor solution according to claim 1 , wherein the particles are resin particles.

6. The particle-dispersed polyimide precursor solution according to claim 2 , wherein the particles are resin particles.

7. The particle-dispersed polyimide precursor solution according to claim 3 , wherein the particles are resin particles.

8. The particle-dispersed polyimide precursor solution according to claim 4 , wherein the particles are resin particles.

9. The particle-dispersed polyimide precursor solution according to claim 1 , further comprising:

an organic amine compound,

wherein a content of the water is 50% by mass or more with respect to a total amount of the aqueous solvent.

10. The particle-dispersed polyimide precursor solution according to claim 9 , wherein the aqueous solvent further contains an aprotonic polar solvent, and a content of the aprotonic polar solvent is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the particles.

11. The particle-dispersed polyimide precursor solution according to claim 1 , wherein a volume-average particle size of the particles is 0.1 μm or more and 1 μm or less.

12. The particle-dispersed polyimide precursor solution according to claim 1 , wherein a content of the particles is 30% by mass or more and 85% by mass or less with respect to a total amount of the polyimide precursor and the particles.

13. A method for producing a porous polyimide film, comprising:

applying the particle-dispersed polyimide precursor solution according to claim 1 to form a coating film, and then drying the coating film to Ram a film containing the polyimide precursor and the particles; and

heating the film to imidize the polyimide precursor to form a polyimide film, which includes a process of removing the particles.

14. A porous polyimide film comprising:

a polyimide obtained by imidizing a polyimide precursor consisting of a polymer of a tetracarboxylic dianhydride and a diamine containing a fluorene-based diamine having a fluorene skeleton; and

pores.

15. The porous polyimide film according to claim 14 , wherein the pore diameter of the pores is 0.1 μm or more and 1 μm or less.