Abstract: A laminate film for forming a tightly sealed bag that can be opened easily by tearing at an edge thereof. The film is a laminate of a substrate layer and a heat seal layer, the substrate layer having a multiplicity of through cuts formed therein, said through cuts being partially or wholly filled by the heat seal layer material.

Abstract: A process for producing a tightly sealed bag that can be easily opened by tearing at an edge thereof. According to the process a multiplicity of through cuts are formed along a line in a laminate film having at least one substrate layer and at least one heat seal layer. The laminate film is formed into an open bag with the line of through cuts provided along an edge to be sealed of the bag and edges of the open bag are heat sealed to form a sealed bag. In an alternative embodiment of the process, a multiplicity of through cuts are formed along a line in a substrate film and a heat seal film is laminated to the substrate film provided with the through cuts to form a laminate film prior to forming the sealed bag.

Abstract: A roll film (1) rolled around a winding core (2), having resin made fastener claws (3) and (4) of an engagement tool along with both edges of the film. The claws are melt-bonded to the film. The film (1) is wound in a serpentine manner relative to the winding core (2). This roll film may be incorporated into an automatic bag producing and filling machine without any intricate operation. When the roll film is paid off, it is possible to smoothly supply the film at a constant speed and to form a fastener claw provided bag with a high efficiency.

Abstract: A device for forming slits, or through cuts, in a plastic film. The device is a disc having a circumferential surface and pseudotriangular slender cutting edges consisting of protrusions aligned linearly in a plurality of straight rows extending around the entire circumferential surface, the protrusions extending outwardly from said circumferential surface at angle of at least 60.degree. and no greater than 100.degree..

Abstract: An antistatic sheet material comprises a substrate layer, an electroconductive layer, and a surface layer. The electroconductive layer is disposed on the substrate layer and contains carbon black in such a manner that the carbon black partly protrudes into the surface layer. The surface layer is a thin transparent plastic layer. The sheet material possesses decreased surface resistance and exhibits excellent antistatic properties. The sheet material permits an object held thereunder to be clearly seen therethrough and enjoys high resistance to surface friction and never deteriorates any object which is in contact therewith. Thus, the sheet material of this invention is used advantageously as containers for objects which by their nature are vulnerable to electrostatic damage.