FR2566007A1 - IMPROVEMENT TO SYNTHETIC FILAMENT MIXED STRETCHING SYSTEMS - Google Patents

Abstract

THIS STRETCHING SYSTEM IS OF THE MIXED STRETCHING TYPE COMPRISING TWO CONTINUOUS PROCESSES, EACH OF THEM CORRESPONDING TO A PARTIAL STRETCHING PHASE, THE FIRST PHASE BEING CARRIED OUT AT THE WET USING A FEED TRAIN FILAMENTS AND A STRETCHING TRAIN 2, A BATH OF LIQUID 3 AND SUBMERGED GUIDE ROLLERS 4 BEING PROVIDED BETWEEN THESE TWO ELEMENTS. THE SECOND STRETCHING PHASE USES THE STRETCHING TRAIN 2 OF THE FIRST PHASE, WHICH THEN WORKS AS A FILAMENT FEED TRAIN, CHARGED WITH SIGNIFICANT QUANTITIES OF LIQUID DUE TO THEIR PASSAGE THROUGH THE BATH 3. THE SAID FILAMENTS ARE CONDUCTED UNTIL 'A HEATED MEANS 6 DOORS AT A TEMPERATURE HIGHER THAN THE MELTING TEMPERATURE OF SAID FILAMENTS IN A DRY STATE. ON THE SAID MEANS 6 THE INSTANT VAPORIZATION OF THE LIQUID CHARGE, AS WELL AS THE STABILIZATION OF THE SAID FILAMENTS IN COOPERATION WITH A FINAL STRETCHING AND STABILIZATION TRAIN, 7.

Description

- 2566007

  IMPROVEMENT TO MIXED STRETCH SYSTEMS

OF SYNTHETIC FILAMENTS

  The present invention relates to an improvement

  mixed stretching systems of synthetic filaments

c.

  More concretely, this improvement relates to

  to improvements in synthetic filament stretching systems and, preferably, filaments

  polypropylene or similar, improvements which

  to provide the heat necessary for drawing

  tact and without pressure, using a procedure

  mixed die in which two partial stretching occurs: the first by heating in a liquid bath and the second

by dry heating.

  The methods of hot drawing of synthetic filaments are already known; these methods present

  However, always the disadvantage is that it is necessary

  to limit the temperature during the processing of

  melting at a low temperature, and this all

  in the case of polypropylene and the like. These low processing temperatures lead to poor stretching of the filaments with all the resulting problems. The object of the invention is to overcome these

  disadvantages and, for that purpose, it puts into play, as indicated

  above, two partial stretches, the first one being

  killed in the wet, using known media while in the second stretch are heated plates

  which provide considerably higher temperatures

  those obtained according to the traditional methods, which can be supported by the filaments during their deterioration due to the introduction of liquid introduced into said filaments during the previous phase of wet drawing. Temperature

  heated plates, on contact with the

  liquid-laden, thus produces a vaporization ins-

  of the latter, thus allowing maximum stretching of the filaments, maximum orientation of their molecules

and maximum stability.

  The present invention will be better understood at

  using the following description of an embodiment

  of the invention, described by way of example, with reference to the appended schematic drawing in which: - Figure 1 is a schematic side view of the installation provided for the mixed drawing method according to the invention;

  - Figure 2 is a top view of the installation

represented in FIG.

  The figures show a feed train consisting of conventional means which, in the case of the present example, consist of rotating rollers (Cl qul, in combination with the drawing train (2), the bath (3) brought to temperature suitable and submerged rollers (4)

  constitute the first partial stretching of the filaments (5).

  The filaments (5) are then without a solution of continuity led to the second drawing means of the system,

  using for this the stretching train (2) which functions

  then as a feed train, and which brings the filaments

  (5) filled with liquid by their passage in the bath

  (3) to the plates (6) heated to a high temperature

  The liquid vaporizes at about 160 ° C., thus allowing the filaments to support said temperature without melting; stretching occurs under these circumstances and the stabilization of the filaments is carried out in cooperation

with the drawing gear (7).

  The process just described makes it possible to obtain

  filaments of high tenacity and maximum stability

  male; the relationship between the speeds of the partial stretches makes it possible to obtain the desired elasticity for the filaments. As is obvious and as is apparent from the above, the invention is not limited to the single embodiment described above as an example; it embraces, on the contrary, all variants, regardless of the liquid media and the material means used.

Claims (1)

- CLAIM -   Improvement to the drawing systems of synthetic filaments and more particularly of polypropylene filaments or the like, of the mixed stretching type, comprising two continuous processes, each of them corresponding to a partial stretching phase, the first phase being carried out in the wet using a filament feed train and a drawing gear (2), a liquid bath (3) and guide rollers   submerged (4) being provided between these two elements,   characterized in that the second stretching phase uses the stretching train (2) of the first phase, which then functions as a filament feed train, loaded with significant quantities of liquid, because of their passage through said bath (3), in that said filaments are conducted to heated means (6) heated to a temperature above the melting temperature of said filaments in the dry state, and in that, on said means (6), instantaneous vaporization of the liquid charge and the stabilization of said filaments by   cooperation with a final stretching and stabilizing tion (7).