THERMOPLASTIC POLYMER COMPOSITION FOR SKELETAL REPLACEMENTS AND METHOD OF ITS PRODUCTION

The invention concerns thermoplastic polymer compositions for skeletal replacements and methods of their production. The composition according to the invention consists of 12 - 91 wt.% of a polyolefm with the glass transition temperature higher than 320 K, which is an ethene - bicyclo[2.2.1]hept-2-ene copolymer with molar concentration of the latter at least 25 % and 75 % at most, of 2 - 72 wt. % of a polyolefm with the glass transition temperature lower than 250 K, which is (i) ethene homopolymer of density at least 0.92 g.cm-3 and 0.97 g.cm-3 at most or (ii) copolymer of ethene with an a-olefin selected from a group consisting of propene, but-1-ene, hex-1-ene, oct-1-ene and dec-1-ene, with density at least 0.85 g.cm-3 and 0.96 g.cm-3 at most or a mixture of ethene homopolymer (i) and ethene - a-olefin copolymer (ii) in any ratio, and of 5-50 wt.% of carbon fibres with the carbon content at least 94 wt.%, density at least 1.80 g.cm-3 and 1.92 g.cm-3 at most and a fibre diameter of at least 4 µm and 9 µm at most. The described composition is prepared by mixing in the melt a polyolefm with the glass transition temperature higher than 320 K and a polyolefm with the glass transition temperature lower than 250 K at a melt temperature of the stirred mixture of at least 430 K. The formed thermoplastic polymer composition is irradiated with ?-rays or accelerated electrons at a dose of at least 20 kGy and 250 IcGy at most, to advantage in inert atmosphere, whereupon the irradiated material is mixed in the melt with carbon fibres at a temperature of at least 430 K. The material can be stabilized against oxidative degradation by admixture of at least 0.1 wt.% of a-tocopherol. L'invention concerne des compositions de polymère thermoplastique pour remplacements squelettiques et leur procédé de fabrication. La composition selon l'invention consiste en de 12 à 91 % en poids d'une polyoléfine ayant une température de transition vitreuse supérieure à 320 K, qui est un copolymère éthène-bicyclo[2.2.1]hept-2-ène avec une concentration molaire de ces derniers d'au moins 25 % et 75 % au plus, de 2 à 72 % en poids d'une polyoléfine ayant une température de transition vitreuse inférieure à 250 K, qui est (i) un homopolymère d'éthène d'une densité comprise entre 0,92 g.cm-3 et 0,97 g.cm-3 ou (ii) un copolymère d'éthène avec une a-oléfine choisie dans un groupe consistant en propène, but-1-ène, hex-1-ène, oct-1-ène et déc-1-ène, avec une densité comprise entre 0,85 g.cm-3 et 0,96