abstract |
A polypropylene composition comprises: (a) a first stabilising component consisting of 100 ppm or less based on the weight of the polypropylene of a phenolic antioxidant or a mixture of phenolic antioxidants; (b) a second stabilising component consisting of 500 to 1000 ppm based on the weight of the polypropylene of a phosphite antioxidant or a mixture of phosphite antioxidants; and optionally (c) a third stabilising component consisting of 100 ppm to 5000 ppm based on the weight of the polypropylene of a hindered amine light stabiliser or a mixture of such stabilisers. The polypropylene composition advantageously is in the form of fibres. A preferred phenolic antioxidant is 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6 dimethylbenzyl)-1,3,5-triazine-2,4,6-( 1 H, 3H, 5H)-trione (Lowinox 1790). A preferred phosphite antioxidant is tris(2,4-di-t-butylphenyl) phosphite (Alkanox 240). A preferred optional hindered amine light stabiliser is dimethyl succinate polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine (Lowilite 62). |