Abstract: The invention concerns a method of producing protective films or the like used as protective covers for photomasks or reticles. To peel a thin film off a substrate, a peeling jig constituted by a flexible annular frame with an adhesive applied thereon is pressed against the thin film applied on the substrate; a portion of the peeling jig is grabbed after the peeling jig and the thin film are adhered together; and the peeling jig and the film are peeled off the substrate. Before adhering the peeled film onto a side end surface of a pericle frame, of the two edges of the pericle frame, at least the edge formed by an inside surface thereof and the side end surface thereof is chambered.

Abstract: An organic membrane is stretched over, or adhered to, a frame or a substrate, and that part of the membrane which extends out of the frame or substrate is cut by bringing an injection syringe-like needle into contact with, or approach to, the lateral end surface of the frame or substrate and while moving the needle along said lateral end surface, injecting an organic solvent from the needle and dissolving said membrane along the lateral end surface of the frame or substrate. By this method, the organic membrane can be cut without generating foreign matter such as cut dust.

Abstract: A gas-permeable seamless pipe structure formed in a pipe shape by a wet process comprising (A) 20 to 95% by weight of thermoplastic fibers and (B) 5 to 80% by weight of a component consisting of (a) 20 to 100% of other fibers being infusible at the fusing temperature of said thermoplastic fibers (A) or having a higher melting point than said thermoplastic fibers (A) and (b) 0 to 80% by weight of a void-containing particulate material having an apparent density of not more than 1 and an average particle size of 20 to 2,000 microns and being infusible at the fusing temperature of said thermoplastic fibers (A), said thermoplastic fibers (A) being bonded to the other component (B) as a result of heat fusing; a method for producing the pipe structure; and an apparatus for use in this method. The pipe structure has superior physical properties such as strength and hardness, good water resistance, light weight and superior gas-permeability.