The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 06, 1994
Filed:
Sep. 24, 1992
DSM N.V., Heerlen, NL;
Abstract
The invention relates to a process for the production of high-molecular-weight polytetramethylene adipamide from equivalent amounts of 1,4-diaminobutane and adipic acid at lower pressures. By supplying 1,4-diaminobutane at an advanced stage of the polycondensation a first polycondensate is obtained that can be extruded very well and that can be aftercondensed in the solid phase to obtain a product with a high molecular weight within a short time. Because of this a substantial overall gain in time is realized. It even appears to be possible to prepare a first polycondensate with a relative viscosity that is high enough for the polycondensate to be further processed into shaped objects. The polycondensation can be carried out both in the melt and in solution. The diaminobutane can be supplied both via the liquid and via the vapour phase.