Black porous polytetrafluoroethylene membrane, method for producing same, gas-permeable membrane and ventilation member using same

摘要

Provided is a black porous polytetrafluoroethylene membrane including a porous polytetrafluoroethylene membrane dyed black. A whiteness of a principal face of the black porous polytetrafluoroethylene membrane as measured according to JIS L 1015 (Hunter method) is 18.0 to 23.0%, and the whiteness of the principal face falls within a range of 18.0 and 25.0% after heating at 350° C. for 1 minute. This black porous PTFE membrane is suitable as a gas-permeable membrane that blocks entry of water and/or dust and that allows permeation of gases; specifically, the black porous PTFE membrane is suitable, for example, as a waterproof sound-transmitting membrane, a waterproof gas-permeable membrane, and a dustproof gas-permeable membrane.

主权项

1. A black porous polytetrafluoroethylene membrane comprising a porous polytetrafluoroethylene membrane dyed black having a porous structure,
wherein the porous structure has voids formed between fibrils of polytetrafluoroethylene, which are fibers of the polytetrafluoroethylene, as pores in the porous structure, a whiteness of a principal surface of the black porous polytetrafluoroethylene membrane as measured according to JIS L 1015 (Hunter method) is in a range from 18.0 to 23.0%, and the whiteness of the principal surface falls within a range from 18.0 and 25.0% after heating at 350° C. for 1 minute.