Verfahren zur Herstellung hochmolekularer technischer Endlosfaeden aus linearen Polymeren

摘要

1311024 Melt-spinning VICKERS-ZIMMER AG PLANUNG UND BAU VON INDUSTRIEANLAGEN 11 Nov 1970 [22 Dec 1969] 53678/70 Heading B5B In a process for the production of continuous filaments of high molecular weight linear polymers a melt of the polymer is supplied at high pressure to a spinning beam assembly at a temperature below the spinning temperature and immediately prior to spinning is passed through a constriction in its flow path to effect a pressure drop and an increase in the internal energy of the melt sufficient internally to heat the particles in the melt uniformly to the spinning temperature, the increased temperature of the internally heated melt being maintained at the spinning temperature by supplying heat externally to the surfaces of the assembly which are contacted by the melt. The spinning temperature of the melt is defined in the Specification as having as its maximum the temperature at which the polymer melt undergoes thermal decomposition and as its minimum the temperature at which melt fracture occurs. The constriction in the melt flow path is preferably formed between the spinning pump and the spinning nozzle plate and is suitably formed by a spinning filter, e.g. of metal sieves having 10,000-50,000 meshes/cm.2. Where the polymer used for spinning is a polyethylene terephthalate the pressure drop #p caused by the constriction is preferably between 150 and 1200 atmospheres, the melt is supplied at a temperature T 1 between 280-330‹ C., the pressure drop is effected at the earliest after 50% of the total melt residence time between generation and spinning, and all surfaces contacted by the melt after the pressure drop #p are maintained at a temperature T 2 within the following limits A suitable spinning beam assembly 1 comprises a pump 2 having an inlet 3 and outlet 4 and surrounded by a heating jacket 13, and a spinning head 5 containing a filter plate 12, a filter support plate 11 spinning nozzle plate 9 and polymer melt inlet 8. The spinning head 5 is surrounded by a heating jacket 14 for maintaining the melt at the spinning temperature T 2 and is inserted in the beam assembly from above in a receiving tube 15 which is closed when the head is in place by an insulating plug 17. Where more than one spinning beam is connected to a single melt supply (18) (Fig. 2, not shown) the product lines (19) from the supply to the assembly are arranged to have equal lengths so that the melt has a uniform residence time for all the spinning positions.