Fine pore formation agent for porous resin film and composition containing the same for porous resin film
View Patent ↗A fine pore formation agent for a porous resin film is provided which comprises inorganic particles satisfying (a) 0.1≦D50≦1.5 (μm) (D50: average particle diameter of particles in 50% cumulative total by weight from the larger particle side by micro-track FRA), (b) Da≦20 (μm) (Da: maximum particle diameter by micro-track FRA), (c) 3≦Sw≦60 (m 2 /g) (Sw: BET specific surface area measured by nitrogen adsorption method), (d) Ir≧1.0×10 5 (Ω·cm) (Ir: volume resistivity (Ω·cm). The fine pore formation agent for a porous resin film is capable of providing a resin composition giving a porous resin film useful in uses for electric parts such as capacitors and battery separators.
1. A fine pore formation agent for porous resin films containing inorganic particles, wherein the inorganic particles satisfy the following formulas (a) to (d) and (f):
0.1≦ D 50≦1.5(μm); (a)
Da≦ 20(μm); (b)
3≦ Sw≦ 60(m 2 /g; and (c)
Ir≧ 1.0×10 5 (Ω·cm) (d)
H x≦ 500(ppm) (f)
wherein
D50: average particle diameter (μm) of particles in 50% cumulative total by weight from the larger particle side in particle size distribution by laser diffraction spectrometry (micro-track FRA);
Da: maximum particle diameter (μm) in the particle size distribution by laser diffraction spectrometry (micro-track FRA);
Sw: BET specific surface area (m 2 /g) measured by nitrogen adsorption method; and
Ir: volume resistivity (Ω·cm) of hydrochloric acid-insoluble matter; and
H X : hydrochloric acid-insoluble matter contained in 500 g of the fine pore formation agent.
2. The fine pore formation agent for porous resin films according to claim 1 , wherein the inorganic particles are selected from calcium carbonate, calcium phosphate, magnesium hydroxide, and barium sulfate.
3. The fine pore formation agent for porous resin films according to claim 1 , wherein the inorganic particles are calcium carbonate.
4. The fine pore formation agent for porous resin films according to claim 1 , wherein the inorganic particles are surfaced treated with a surfactant (A) and a compound (B) having a chelating function to alkaline earth metals.
5. The fine pore formation agent for porous resin films according to claim 1 , wherein the inorganic particles satisfy the following formula (e):
1≦ As≦ 4(mg/m 2 ) (e)
wherein
As: heat loss per unit specific surface area calculated according to the following equation [heat loss per 1 g of surface treated inorganic particles at a temperature in a range from 200° C. to 500° C. (mg/g)]/Sw (m 2 /g).
6. The fine pore formation agent for porous resin films according to claim 1 , wherein the inorganic particles satisfy the following formula (g):
Fc≦ 30(ppm) (g)
wherein
Fc: hydrochloric acid-insoluble free carbon contained in 500 g of the fine pore formation agent.
7. A composition for a porous resin film which comprises mixing the fine pore formation agent according to claim 1 with a resin for a porous film.
8. The composition for a porous resin film according to claim 7 , wherein the resin for a porous film is an olefin type resin.
9. A battery comprising:
two electrodes, and
a porous resin film made of the composition for a porous resin film according to claim 7 , positioned between the electrodes.