FIELD: production of multiplayer materials from polymer films. SUBSTANCE: invention relates to production of multiplayer material from polymer films with linear weld joint, device for making such materials and articles made from such materials. Method of head welding of at least two polymer shrinkable films includes heating of films with resulting shrinkage of each film in plane and increase of thickness of each film. Simultaneously pressure in applied to compressed zone to form weld joint containing connected zone and nonconnected zone in which film is thickened. At initial stage, heat and pressure are applied to initial pressure zone. At second stage, heat and pressure are applied to second pressure zone which overlaps initial pressure zone, extends from boundary of initial pressure zone and includes, at least part of remaining compressed zone. Simultaneously pressure is reduced at least in part of initial zone adjacent to boundary of compressed zone. At least one of welding elements is rolled relative to other welding element. Heating and pressure are maintained in zone of overlapping from beginning of initial stage to end of second stage. According to second version, stage of opening of welding buses consists of rolling the buses relative to each other over expanded parts of buses at one side of weld joint. Expanded parts are exposed to temperature lower than minimum welding temperature. Expanded parts hold material during part of cooling period to decrease shrinking of weld joint in longitudinal direction. Invention contains description of multiplayer material with weld joint, pack of thermoweldable polymer material and welder for implementing the method. EFFECT: provision of weld joint of high breaking strength at impact. 38 cl, 10 dwg
