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Abstract

A method for making sheets and/or plates that are thermoformable as of a temperature of 80-90.degree. C. and heat-tackifiable as of 80-90.degree. C., and suitable for use as a heat-tackifiable reinforcing material. According to the method, 30-70 wt % of granules of one or more polymers that have a low melting point (50-90.degree. C.) and are thermoformable as of 80-90.degree. C. are mixed with 70-30 wt % of one or more polymers with a higher melting or softening point, in the form of granules or a powder having a particle size greater than around 500 .mu.m, and preferably of 500-1000 .mu.m, both kinds of polymers being thermoplastic and at least partially compatible, and optionally with the usual additives; the mixture is extruded under low-shear conditions at low temperatures of 100-140.degree. C. to give a mixture having a pasty consistency that is insufficient to form a uniform mixture of molten polymers; and, after extrusion, and optionally once a fabric base (9,12) has been added to the extruded product, the product is laminated or calendered at a high pressure and at a temperature of around 100.degree. C. to reduce the thickness thereof, then cooled to less than 30.degree. C. before the end of the lamination or calendering process.

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