Method for reprocessing aqueous extract solutions obtained in the production of PA 6 or copolyamide
AssigneeBayer Aktiengesellschaft
InventorsAndreas Gittinger, Claus Wulff, Heinrich Haupt, Karsten-Josef Idel
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Abstract
The invention relates to a method for recycling (reprocessing) aqueous extract solutions obtained in the production of polyamides. The method for reprocessing the aqueous extract solutions obtained consists in that the aqueous extract solution is concentrated and polymerised, adding small amounts of dicarboxylic acid or polycarboxylic acid to the extract solution.
Claims10
A method for reprocessing aqueous extract solutions obtained in the production of polyamide 6 or copolyamides containing not less than 70% by weight of repeating units derived from .epsilon.-caprolactam, which comprises obtaining and concentrating an aqueous extract solution, and adding 0.02 to 20 mmol of dicarboxylic acid or polycarboxylic acids per kg extract (dry matter) to the extract prior to, during or after concentration.
In a process of reprocessing and polymerizing the aqueous extract solution from the production of polyamide 6 or copolyamides, the improvement which comprises increasing the rate of polymerization by addition of dicarboxylic acid or polycarboxylic acid to the extract.
Dependencies are inferred from the claim text.