Polyimide precursor solution and polyimide film
A polyimide precursor solution contains resin particles and a polyimide precursor. The resin particles in the polyimide precursor solution have a volume particle size distribution with one or more peaks. The volume frequency of a peak having the highest volume frequency of the one or more peaks accounts for 90% to 100% of the total volume frequency of all peaks of the volume particle size distribution.
1. A polyimide precursor solution comprising:
resin particles having surface acidic groups;
an aqueous solvent comprising water; and
a polyimide precursor, wherein
the resin particles are formed of a resin selected from the group consisting of polyester resins, urethane resins, vinyl resins, olefin resins, and fluorocarbon resins.
2. The polyimide precursor solution according to claim 1 , wherein the resin particles in the polyimide precursor solution have a volume particle size distribution with one or more peaks, and the volume frequency of a peak having the highest volume frequency of the one or more peaks accounts for 90% to 100% of the total volume frequency of all peaks of the volume particle size distribution.
3. The polyimide precursor solution according to claim 2 , wherein the resin particles in the polyimide precursor solution have a volume particle size distribution index of 1.30 or less.
4. The polyimide precursor solution according to claim 1 , wherein the acidic groups are at least one type of acidic group selected from the group consisting of carboxy, sulfo, and phenolic hydroxy groups.
5. The polyimide precursor solution according to claim 1 , wherein the resin particles have an average particle size of 0.1 to 0.5 μm.
6. The polyimide precursor solution according to claim 1 , wherein the resin particles are present in an amount of 20 to 600 parts by mass based on 100 parts by mass, on a solid basis, of the polyimide precursor.
7. The polyimide precursor solution according to claim 1 , wherein water is present in the aqueous solvent in an amount of 50% to 100% by mass based on the total mass of the aqueous solvent.
8. The polyimide precursor solution according to claim 1 , further comprising an organic amine compound.
9. The polyimide precursor solution according to claim 8 , wherein the organic amine compound is a tertiary amine compound.
10. The polyimide precursor solution according to claim 8 , wherein the organic amine compound is an amine compound having a nitrogen-containing heterocyclic structure.
11. The polyimide precursor solution according to claim 1 , further comprising an aprotic polar solvent in an amount of 5% to 300% by mass based on the mass, on a solid basis, of the polyimide precursor in the polyimide precursor solution.
12. A polyimide film obtained by applying the polyimide precursor solution according to claim 1 to form a coating and heating the coating.
13. The polyimide film according to claim 12 , wherein the polyimide film is further subjected to resin particle removal treatment.
14. The polyimide film according to claim 13 , wherein the resin particle removal treatment is performed by heating the resin particles or dissolving the resin particles in an organic solvent.
15. The polyimide film according to claim 13 , wherein the polyimide film is further subjected to resin particle exposure treatment before the resin particle removal treatment.
16. The polyimide precursor solution according to claim 1 , wherein the resin forming the resin particles is selected from the group consisting of (meth)acrylic resins, (meth)acrylate resins, styrene-(meth)acrylic resins, and polystyrene resins.
17. The polyimide precursor solution according to claim 1 , wherein the polyimide precursor has not been imidized.
18. The polyimide precursor solution according to claim 1 , wherein the surface acidic groups are functional groups of repeating units of the resin, and the functional groups are independently selected from the group consisting of a carboxy group, a sulfo group, and a phenolic hydroxy group.