Abstract: A method of continuously manufacturing a corrugated tube having a corrugated outer wall and a smooth inner wall surface along the length of the tube is provided which method comprises the steps of arranging in a circular array a plurality of rollers each rotating at the same speed such that an imaginary cylinder is defined about its central axis by said rollers, the longitudinal axes of said rollers being parallel to each other but offset with respect to said central axis; continuously feeding a flat non-reinforced strip of synthetic resin material in a softened state generally perpendicularly to the length of said rollers in such a manner that said strip is helically wrapped around and advanced axially along said imaginary cylinder with portions of adjacent turns of the strip overlapping one on another and welded together; continuously feeding a flexible core member and embedding it between the overlapping portions of adjacent turns of the strip to raise the upper one of said overlapping portions so as to de

Abstract: A composite packing film is provided which comprises a base film having relatively small longitudinal and transverse elongations of not more than 10%, a layer of unidirectionally elongated film elongated in one direction and laminated on one face of said base film through an adhesive, a layer of an elongated film elongated at least in the direction substantially perpendicular to said first direction and laminated on the other face of said base film through an adhesive, and a sealant layer having a melting point lower than those of said elongated films and laminated on either one of the external faces of said elongated films, the difference between the resistance against end tearing of said unidirectionally elongated film and the resistance against end tearing of said latter-mentioned elongated film being not less than 15 kg. A packing bag made of the composite film is also provided.

Abstract: A method and apparatus for continuously forming a corrugated tube from a strip of synthetic resin in a softened state by the use of a plurality of rotating rollers arranged in a circular array such that said rollers define an imaginary cylinder about its central axis with the axes of said rollers being parallel to each other but angled relative to the central axis of the imaginary cylinder whereby as the rollers rotate the strip is helically wrapped around and advanced axially along said imaginary cylinder with portions of adjacent turns of the strip overlapping and joined together to form a continuous tube; characterized in that each of said rollers is provided with a plurality of axially spaced annular ridges therearound, said ridges of the respective rollers being so arranged that the associated successive ridges of each adjacent rollers are aligned in a spiral path around said imaginary cylinder.

Abstract: An adhesive tape is provided which comprises a film of high density polyethylene having a density of not less than 0.94g/cc elongated at least six times only transversely to the longitudinal direction of the tape and a layer of pressure sensitive adhesive applied at least on one side of said elongated film of high density polyethylene. The adhesive tape has a high tensile strength against a force applied in a direction transverse to the longitudinal direction of the tape. Nevertheless, the tape can be easily torn or cut by user's hand or hands exactly transversely to the longitudinal direction of the tape without being torn zigzag or in a slanting direction.

Abstract: An adhesive tape is provided which comprises a base paper material having a thickness of 30 to 150 g/m.sup.2, a film of high density polyethylene having a density of not less than 0.94 g/cc elongated at least six times only transversely to the longitudinal direction of the tape and having a thickness of 15 to 30.mu., said elongated film being attached to one side of said base paper material with a first layer of low density polyethylene of a thickness of 7 to 50.mu. being extruded between the base paper material and the elongated film, a second layer of low density polyethylene of a thickness of 7 to 50.mu. being extruded and attached to said elongated film so that the elongated film is sandwiched between the first and second layers of low density polyethylene, and a layer of pressure sensitive adhesive applied to the other side of said base paper material. The adhesive tape has a high tensile strength against a force applied in a direction transverse to the longitudinal direction of the tape.

Abstract: An adhesive tape is provided which comprises a film of high density polyethylene having a density of not less than 0.94 g/cc elongated at least six times only transversely to the longitudinal direction of the tape and a layer of pressure sensitive adhesive applied at least on one side of said elongated film of high density polyethylene. The adhesive tape has a high tensile strength against a force applied in a direction transverse to the longitudinal direction of the tape. Nevertheless, the tape can be easily torn or cut by user's hand or hands exactly transversely to the longitudinal direction of the tape without being torn zigzag or in a slanting direction.

Abstract: Apparatus for continuously shaping a heated thermoplastic synthetic resin sheet into a desired configuration followed by any desired processing, wherein the synthetic resin sheet extruded from a forming die is drawn by suction onto a shaping surface of the apparatus main body which is provided therein with a heat transfer medium accommodating chamber to constantly maintain the shaping surface of the main body at an appropriate temperature by quickly heating the shaping surface to an appropriate temperature prior to commencement of operation of the shaping apparatus, and by cooling the shaping surface to prevent the same from temperature rise due to contact with the heated synthetic resin sheet after the shaping apparatus starts operation. The apparatus is further provided with a heat transfer medium feeding means to automatically feed the heat transfer medium at a desired temperature into the heat transfer medium accommodating chamber.