PROCEDIMENTO PER LA PRODUZIONE DI MATERIALE PER IMBOTTITURE

1488270 Laminating method DYNAMIT NOBEL AG 31 Dec 1974 [22 Jan 1974] 56237/74 Heading B5N A process for the production of a padding structure, e.g. a dashboard or internal side section of a motor vehicle comprises disposing a synthetic thermoplastic plastics sheet having a dielectric constant of from 2À5 to 6 and a dielectric loss factor greater than 1À5 Î 10-3 on each face of a sheet of polyethylene foam to contact the latter, one of the sheets being flexible and the other being sufficiently rigid to provide a support for the polyethylene foam or being flexible and having the face thereof opposite to that contacted by a sheet material sufficiently rigid to provide a said support, the flexible other sheet being attached to the sheet material or being capable of bonding to the sheet material under high-frequency welding conditions, and subjecting the resultant assembly to highfrequency welding conditions using a highfrequency welding tool shaped so as to cause polyethylene foam to be pushed away thereby at a plurality of positions so that only thin neck portions of foam remain between the sheets and the sheets are welded together at positions at which the tool acts to leave polyethylene foam unbonded to the sheets at locations outside the positions. A thermoplastic plastics sheet is defined as being a sheet material formed of plastics material and in the form of a foil or a fabric, e.g. a woven or knitted fabric, specified materials therefore being, for the support, polyvinyl chloride or an ethylene copolymer and for the flexible sheet, ethyl cellulose, acetyl cellulose, polyvinyl chloride, a vinylidene chloridevinyl chloride copolymer, a polymethacrylate, an acrylonitrile-butadiene-styrene copolymer, a copolymer of ethylene, e.g. with vinyl acetate, or a polyamide. Specified separate sheet materials are parchment paper or board, cardboard, metal and plywood. In a modification of the process, a decorative film can be applied to the thermoplastics sheet disposed above the foam; alternatively, the plastics sheet may be decorative. In Fig. 1, 1 is thick parchment paper, 2 an ethylene copolymer, 3 a polyethylene foam, 4 a polyamide knitted fabric and 6 the bonding seams, air spaces 5 existing between the seams 6. The embodiment shown in Fig. 2 comprises a decorative polyvinylchloride film 7 a polyethylene foam 8 and ethylene copolymer 9 on a thick parchment paper sheet 10, 11 designating the weld seams.