Abstract:
The invention relates to a process for preparing a semi-aromatic polyamide from diamine and dicarboxylic acid, comprising steps of •(i) dosing a liquid diamine to an agitated powder comprising an aromatic dicarboxylic acid thereby forming a powder comprising a diamine/dicarboxylic acid salt (DD-salt), and •(ii) solid-state polymerizing the DD-salt to obtain the polyamide.
Abstract:
The present invention relates to a new process for the preparation of ammeline and/or ammelide from melamine by a solid-to-solid reaction in an aqueous reaction mixture comprising a biocatalyst, wherein the biocatalyst comprises at least one enzyme belonging to the amidohydrolase superfamily and having aminohydrolase activity towards 1,3,5-triazine compounds. The invention further relates a product obtainable by the process according to the invention, wherein the product comprises ammeline and/or ammelide.
Abstract:
The invention relates to a process for preparing a salt from diamine and dicarboxylic acid, the process comprising contacting a diamine gas, having a gas temperature T-gas, with a dicarboxylic acid, thereby forming a reaction mixture comprising diamine/dicarboxylic acid salt, wherein the dicarboxylic acid and the reaction mixture are kept at a temperature T-mixture of at least 10° C. below the lowest of the melting temperature of the dicarboxylic acid (Tm-acid) and the melting temperature of the resulting diamine/dicarboxylic acid salt (Tm-salt). The invention also relates to a process for preparing a polyamide comprising preparing a salt from diamine and dicarboxylic acid.
Abstract:
The invention relates to a flame-retardant polyamide composition comprising a polyamide with a melting temperature higher than 265° C. and ammeline and/or ammelide, in which the ammeline and/or ammelide is obtainable by a biocatalytic process from melamine in an aqueous reaction mixture comprising a biocatalyst, wherein melamine is converted into ammeline and optionally further into ammelide.
Abstract:
The invention relates to a process for the preparation of semi-crystalline semi-aromatic polyamide by direct solid-state polymerization of a diamine-dicarboxylic acid salt, comprising steps of (a) providing at least two salts of terephthalic acid and diamine, wherein each of these diamine/terephthalic acid salts is in solid state and has a melting temperature of at least Tx, wherein Tx is at least 260° C.; (b) preparing a mixture of the diamine/terephthalic acid salts, while retaining the salts in solid state; and (c) heating the mixture obtained from step (b) in the solid state to a temperature (T-c) in the range from 200° C. to 260° C., under a pressure below the saturation vapor pressure of water at said temperature, thereby condensing and polymerizing the salts and forming a semi-crystalline semi-aromatic polyamide in solid form.