Abstract: Disclosed herein is a biaxially oriented paraphenylene sulfide block copolymer film showing a heat shrinkage of 0-2.0% at 100.degree.-220.degree. C., comprising a paraphenylene sulfide block copolymer essentially composed of recurring units (A): ##STR1## and recurring units (B): ##STR2## the molar fraction of recurring units (A) being 0.50-0.98, and having a melt viscosity (.eta.*) of 1,000-15,000 poises as measured at 310.degree. C. and shear rate of 200 sec.sup.-1, a glass transition temperature (Tg) of 20.degree.-80.degree. C., a crystalline melting point (Tm) of 250.degree.-285.degree. C. and a crystallization index (Ci) of 15-45 (measured with the non-stretched heat-treated polymer film), and a process for producing the biaxially oriented paraphenylene sulfide block copolymer film.

Abstract: Disclosed herein is a process for producing a biaxially oriented paraphenylene sulfide block copolymer film, comprising melt extruding and molding a paraphenylene sulfide block copolymer essentially composed of recurring units (A): ##STR1## and recurring units (B): ##STR2## the molar fraction of recurring units (A) being 0.50-0.98, and having a melt viscosity (.eta.*) of 1,000-50,000 poises as measured at 310.degree. C. and shear rate of 200 sec.sup.-1, into a film, and after cooling, biaxially stretching the thus molded film at a stretching temperature (T) defined by the following formula:96-50X<T<116-66.7Xwherein T is a stretching temperature (.degree.C.

Abstract: A method and laminate for protecting an article from exposure to radiant heat are disclosed. The laminate is formed by adhering a metal coating to one surface of a polymeric film of polyfluoroolefin or fluoroolefin copolymer, having not more than a 50% transmission ratio of visible ray and not less than a 30% transmission ratio of infrared ray. The laminate is adhered to a surface of the article to be protected with the polymeric surface outward.

Abstract: For making a piezoelectric thermoplastic film device, a polar thermoplastic film is provided on both sides thereof with conductive layers which function as polarizing electrodes during the polarizing step. In a polarizing zone, a polarizing voltage is applied across the electrodes while the film is heated to a suitable polarizing temperature. To reduce undesirable capacitive effects, at least one electrode layer is separated into sections by narrow insulating regions extending transversely across the film. After cooling, the polarizing voltage and the accumulated electric charges in the film are removed.

Abstract: A method of polarizing high molecular weight films comprising polarizing elongated strips of polar high molecular weight film upon which conductive thin films as opposing electrodes are deposited on both surfaces thereof the strips being assembled in an even number of layers and wound around a core into a roll shape. An embodiment includes inserting electrically insulating spacer layers between each layer or each unit of an even number of layers to prevent discharge effects.