摘要:
The invention relates to a process for preparing a melt-processable polylactam by contacting caprolactam monomer with an anionic polymerization catalyst, polymerizing said monomer and contacting the resulting polylactam with a protic compound. The anionic polymerization catalyst is chosen from the group of alkali-earth-metal-lactamates and alkali-earth-metal-lactamate forming compounds and the protic compound has a pKa larger than 14. The resulting polylactam has a good melt-stability and very low cyclic dimer content.
摘要:
The invention relates to a process for recycling polyamide-containing carpet waste by extracting the polyamide from the carpet waste with an extraction agent containing an aliphatic alcohol, after which the polyamide is recovered from the extract. The process according to the present invention gives a high yield of the polyamide. The presence of other constituents normally used in carpet-making does not interfere with the recycling.
摘要:
Process to separate ε-caprolactam from an aqueous mixture containing ε-caprolactam and at least 0.5 wt% oligomers, wherein the separation is performed by extraction using an organic extraction agent. The aqueous mixture may be obtained in a process to prepare ε-caprolactam starting from 6-aminocapronitrile or in a process to prepare ε-caprolactam starting from 6-aminocaproic acid.
摘要:
The invention relates to a method of preparing ε-caprolactam by depolymerisation of nylon-6 originating from carpet wate wherein the mixture of ε-caprolactam and water is hydrogenated in the presence of hydrogen and a hydrogenation catalyst. The amount of ε-caprolactam in the mixture can be between 10 and 95% by weight.
摘要:
The invention relates to a process for the preparation of a compound containing polyisocyanate and isocyanurate groups through trimerisation of 1,4-tetramethylenediisocyanate (TMDI), using a trimerisation catalyst, and the purification of the trimer desired, characterised in that the trimerisation is effected at a temperature below 90°C, the purification being effected through extraction, using an apolar solvent with a boiling point below 180°C, and evaporation of the solvent under lowered pressure, at a temperature below 90°C.
摘要:
The invention relates to a process for depolymerising one or more polyamides in the presence of at least an aliphatic alcohol, the depolymerisation taking place with at most 40 mol.% catalyst. This process provides good selectivity towards the monomeric components of polyamides. This process moreover causes as few waste streams as possible.
摘要:
Process for the depolymerization of one or more polyamides in the presence of at least a nitrogen-containing compound, the depolymerization taking place at a pressure between 0.5 and 5 atm. As a result a better selectivity towards the monomeric components of polyamides is obtained.