An aqueous dispersion of polytetrafluoroethylene (PTFE) comprising from 55 to 70 mass% of PTFE fine particles having an average particle diameter of from 0.1 to 0.5 µm, from 0.0001 to 0.02 mass%, based on PTFE, of a specific C8 fluorine-containing carboxylic acid salt (APFO) such as ammonium perfluorooctanoate, from 1 to 20 mass%, based on PTFE, of a specific nonionic surfactant and from 0.01 to 0.3 mass%, based on PTFE, of a specific C5-7 fluorine-containing carboxylic acid salt such as ammonium perfluorohexanoate.
The aqueous dispersion of PTFE has excellent properties which can form crack-resistant coatings which do not undergo coloration during baking or form problematic ionic impurities by improving the friction stability of aqueous PTFE dispersions even at APFO concentrations without viscosity increase.
一种聚
四氟乙烯(P
TFE)的
水性分散体,包含 55 至 70 质量%的 P
TFE 细颗粒,其平均粒径为 0.1 至 0.5 微米;0.0001 至 0.02 质量%(以 P
TFE 计)的特定 C8 含
氟羧酸盐(APFO),如
全氟辛酸铵;1 至 20 质量%(以 P
TFE 计)的
全氟辛酸铵。02 质量%(以 P
TFE 计)的特定 C8 含
氟羧酸盐(APFO),如
全氟辛酸铵;1 至 20 质量%(以 P
TFE 计)的特定非离子表面活性剂;以及 0.01 至 0.3 质量%(以 P
TFE 计)的特定 C5-7 含
氟羧酸盐,如
全氟己酸铵。
聚
四氟乙烯水性分散体具有优异的性能,可以形成抗裂涂层,在烘烤过程中不会着色,也不会形成有问题的离子杂质,即使在 APFO 浓度下也能提高聚
四氟乙烯水性分散体的摩擦稳定性,而不会增加粘度。