摘要 |
Fibre material and at least one plastic material is extruded in such a way that a composite product (11) is produced. To increase the strength of the product (11) and to improve its heat resistance, the at least one plastic material of the product (11) is cross-linked in such a way that at least a surface of the wall of the product (11) is provided with a cross-linking degree higher than the cross-linking degree of an inner part of the wall of the product (11). |