| abstract |
The invention relates to a method for producing a moulded part (50) by structural foam moulding, in which a polymer melt (18) is provided by melting a thermoplastic material, in which the polymer melt (18) is charged with a foaming agent (22) and in which the polymer melt (18) charged with the foaming agent (22) is injected under pressure into a cavity (26) of a mould (28), and so the polymer melt (18) fills the cavity (26) behind a melt front (34) running through the cavity (26), wherein the rate of injection at which the polymer melt (18) is injected into the cavity (26) of the mould (28) is set such that the internal pressure of the polymer melt (18) in the cavity (26), in a region (40) that follows a portion of the melt front (34) with a time delay of at most 0.15 seconds, is greater than the critical pressure of the foaming agent (22), at least at one point in time during the injection-moulding operation. The invention also relates to a moulded part (50) of an expanded thermoplastic material, wherein the moulded part (50) has a surface region with visual structuring formed by the expanded thermoplastic material of which the average ratio of the degrees of gloss measured in the direction of flow in relation to the degrees of gloss measured transversely to the direction of flow is below 1.9, preferably below 1.5, in particular below 1.2. The invention also relates to uses of such a moulded part. |