Patent NZ-588828-A (NZ)
Title: Method for reducing the crystallization temperature and the melting temperature of a polyamide powder during polymerization
Inventor: FILOU GREGORY
IPC: B29C67/00
Filed: 2009-04-29
Abstract: Disclosed is the use of at least one minor co-monomer in a process for polymerizing at least one major monomer in order to reduce the crystallization temperature and the melting temperature of a polyamide derived from the polymerization of said at least one major monomer, and in order for the decrease in crystallization temperature to be greater than the decrease in melting temperature, respectively, relative to the crystallization temperature and the melting temperature of the polyamide resulting from the polymerization of said at least one major monomer, said melting and crystallization temperatures being measured by DSC according to standard ISO 11357-3, said at least one minor co-monomer being polymerized according to the same polymerization process as said at least one major monomer, and said at least one minor co-monomer being chosen from aminocarboxylic acids, diamine-diacid couples, lactams and/or lactones, and said at least one minor co-monomer representing from 0.1% to 20% by mass of the total blend of said monomer (s) and co-monomer (s), preferably from 0.5% to 15% by mass of said total blend, and preferably from 1% to 10% by mass of said total blend, said at least one major monomer comprising 11-aminoundecanoic acid and/or lactam 12 and/or the decanediamine-sebacic acid couple (10.10). A process for reducing the crystallization temperature and the melting temperature of a polyamide derived from the polymerization of at least one major monomer is also disclosed, wherein said process comprises a step of polymerization of said at least one major monomer with at least one different minor co-monomer polymerized according to the same polymerization process as said at least one major monomer, said at least one minor co-monomer comprising 11-aminoundecanoic acid and/or lauryllactam and/or caprolactam and/ or caprolactone and/ or at least one of the following diamine-diacid couples: 6.6, 6.10, 6.11, 6.12, 6.14, 6.18, 10.10, 10.12, 10.14, 10.18 and/or 10.T, T being terephthalic acid, said at least one minor co-monomer representing from 1% to 7% by mass of the total blend of said monomer(s) and co-monomer(s), preferably 1% to 5% by mass of said total blend, such that the reduction in the crystallization temperature is greater than the reduction in the melting temperature, respectively, relative to the crystallization temperature and the melting temperature of the polyamide obtained from the polymerization of said at least one major monomer, said melting and crystallization temperatures being measured by DSC according to standard ISO 11357-3, said at least one major monomer comprising 11-aminoundecanoic acid and/or lactam 12 and/or the decanediamine-sebacic acid couple (10.10). Said process is particularly useful in powder aggregation technology of polyamide powders by radiation-mediated melting or sintering, for instance using a laser beam (laser sintering), infrared radiation or uv radiation or any source of electromagnetic radiation that makes it possible to melt the powder in order to manufacture articles.