Patent ID: 7931959

Claim:
A thermoplastic polymer composition comprising at least one enhanced melt flow polyamide matrix and fibrous filler material that can be shaped into articles having a maximum core thickness of less than or equal to 600 μm according to the following test: a) injection molding said composition to obtain a dumbbell test specimen of type 1A for a tensile test according to the standard ISO 527-2 employing a slit aperture gating at the end of the head of the test specimen; the test specimen having the following dimensions: length of 180 mm, working length of 80 mm, working width of 10 mm and thickness of 4 mm; the injection molding being carried out according to the standards ISO 294-1 and ISO 1874-2 by means of a mold with a T-runner comprising two cavities, as described in Annex A—ISO 294-1; with the following characteristics: an injection-molding press equipped with a standard screw having a diameter of 35 mm for thermoplastics comprising a three-zone profile (feed, compression, homogenization), having an L/d ratio equal to 22 and a compression ratio of 2/1; injection at a speed of 80 cm 3 /s; an injection time of 0.8 s; b) cutting a cube from the middle of the test specimen and analyzed by high-resolution X-ray microtomography to obtain a succession of radiographs and thus reconstruct the 3D volume of the cube; c) the Euler angles are determined for each fiber in the reconstructed 3D volume of the cube using image analysis software: σ(theta) corresponds to the angle between a single fiber and its projection in the plane of the test specimen comprising the length and the width of the test specimen; ρ(phi) corresponds to the angle between the projection of a fiber in the plane of the test specimen and the injection direction; the value A is then calculated that corresponds to the component a11 of the orientation tensor a2 corresponding to the average value of cos 2 ρ·sin 2 σ for all of the fibers throughout the thickness of the test specimen, and the values B are also calculated that correspond to the components a11 of the orientation tensor a2 corresponding to the average value of cos 2 ρ·sin 2 σ for all of the fibers in various slices of the thickness of the test specimen; d) the maximum core thickness is measured on a graph that represents the values B for each slice of the thickness of the test specimen (total thickness of 4 mm).