Pfas-free composite cap liner and venting port membrane

A composite non-PFAS gas-permeable and liquid-impermeable cap liner and venting port membrane (10) configured to fit between a closure cap (2) and a rim (9) surrounding a dispensing aperture (31) of a container (8), the composite cap liner and venting port membrane (10) comprising:

• a disc-shaped liner body (11) comprising a material that is substantially gas-impermeable and liquid-impermeable, the liner body having a bottom surface (13) facing the rim (9) surrounding the dispensing aperture (31) of the container and an opposing top surface (12) facing an inner top wall (4) of the closure cap (2), the liner body (11) having a venting port (16) that extends through the liner body from the top surface (12) to the bottom surface (13) and having a venting port periphery (17) that is less than a periphery (14) of the liner body;
• a venting port membrane (20) made of a microporous expanded and ultrahigh molecular weight polyethylene (ePE) layer (21) that is gas permeable and compatible for use with oxidizing agents in cleaning products containing bleach or hydrogen peroxide, the venting port membrane being bonded at its periphery (24) to a peripheral area (17) surrounding the venting port (16) on either the bottom or top surfaces of the liner body (11) to provide a single gas-permeable venting port membrane (20) through the liner body that is also liquid-impermeable, and wherein the composite liner body and venting port membrane (10) are substantially free of per- and polyfluoroalkyl (PFAS) substances.