Production of polyamide
View Patent ↗The present invention provides a method for the production of polyamide 6 by the hydrolytic polymerization of ε-caprolactam, in which, in the first step, caprolactam ring opening occurs under the action of water and, in the following steps, polycondensation is performed at low temperatures under anhydrous conditions.
1. In a process for the production of polyamide 6 or copolyamide based on polyamide 6 in at least two stages, in which a polyamide from the first stage(s) is melt postcondensed, the improvement comprising:
melt postcondensing with an increased melt surface area with a surface area/volume ratio of >20 m −1 , using a stream of inert gas and/or with a reduction in overall pressure, and performing melt postcondensation at a temperature between melting point and melting point +40° C.
2. The process according to claim 1 , wherein the postcondensation proceeds at a temperature which is between melting point and melting point +35° C.
3. The process according to one of the preceding claims, wherein delactamisation proceeds simultaneously during the postcondensation.
4. The process according to one of claim 1 or 2 , wherein the melt leaving the postcondensation is directly provided with fillers and/or additives or is chemically modified by means of mixing means.
5. The process according to claim 4 , wherein the mixing means is selected from twin-screw extrusion, static or dynamic mixers.
6. The process according to one of claim 1 or 2 , wherein the polyamide from the first stage(s) is produced at a temperature of <240° C.
7. The polyamide produced according to one of claims 1 or 2 .
8. The molding composition comprising the polyamide produced according to one of claim 1 or 2 .
9. A method of making a molding composition comprising mixing the polyamide according to claim 7 with fillers and/or additives or chemically modifying the polyamide by means of mixing means.
10. The molding produced with a polyamide 6 made according to one of claim 1 or 2 .
11. The process according to claim 1 , wherein the polyamide is a prepolyamide.