Transformation-stable composition comprising viscous polyamide, production thereof and use of same

A method for forming a composition which exhibits a good melt viscosity and which is stable during transformation comprising the step of combining:

• about 50 ppm to about 5000 ppm of at least one catalyst,
• about 0.05% to about 1% of at least one copper-based heat stabilizer,
• and about 0.1% to about 3% of at least one oligo- or polycarbodiimide with a matrix comprising at least one polyamide;
• wherein said melt viscosity is from about 13,000 to about 23,000 Pas, as determined by oscillatory rheology at 270° C. at 10 rad/sec while flushing with nitrogen with 5% deformation and shearing of 10 sec-1 between two parallel plates with a diameter of 25 mm, and
• wherein said stable in transformation means that the melt viscosity does not change by more than 70% as a function of time between 1 minute and 30 minutes during a melt process,
• wherein the catalyst is chosen from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2) or a mixture of these,
• wherein the copper-based heat stabilizer comprises copper iodide,
• wherein the polyamide is chosen from:
• PA 11, PA 12, 11/10.T, PA 10.10, PA 10.12.