CS259580B1 - Method of polypropylene conjugated fibres' volume expansion - Google Patents

Abstract

Bulking polypropylene conjugated fibers with xnaximal use fiber-forming capabilities. Conjugated the fibers are first heated on the galette with a temperature in the range of 80 to 145 ° C and above the following in the draw-off collector are heated hot air to the temperature at which the fibers get the biggest drop precipitation forces, ranging from 110 to 160 degrees Celsius depending on the kind used polypropylene conjugated fibers ken.

Description

The invention relates to a process for increasing the volume of polypropylene conjugated fibers at a temperature determined by the temperature and time dependence of the clotting forces. The fibers are heated on the galet and in the nozzle and become larger in the container.

several methods of the invention are known, such as US Pat. No. 3,533,904, according to which the conditions of relaxation in softening are related to the conditions of debt and also to other operations in preparation.

Similarly, U.S. Pat. file no. 3,655,889 relaxation is determined by a temperature range of 25 to 140 ° C. j

In GB Pat. file no. No. 1,183,410 is relaxation characterized by the temperature of the galet to be diverted and the different velocity of the recovery galet after it is diverted. The temperature of the galet is given in the range from ambient temperature to 140 ° C.

The same is true of Japanese inventions. JP (A) Pat. file no. 38 887/73, in the process of producing a filamentous fiber from POP, indicates a 5- to 30% shrinkage when relaxed with heating from 60 to 140 ° C.

According to JP (A) Pat. file no. 20 890/73 relaxation is performed at a temperature of 80 to 110 ° C and a time below 15 minutes.

In JP (A) Pat. file no. 78 511/66, the softening conditions in the temperature range of 100 to 130 ° C are given. The precipitation level ranges from 20 to 60 ° / o.

In all cases, it is believed that in the refinement, the potential of the conjugated fibers is transformed into a curved shape and the process conditions determine the quality of the finished product. Higher stresses reduce the filament strength of the filament and therefore the filament is carried out in a relaxed state as in the above procedures. The temperature level in the above procedures is not specified. Also, the problem of precipitation time dependence, which is significant especially at high speeds, has not been solved.

The above-mentioned drawbacks are overcome by the solution according to the invention, which consists in that the conjugated fibers are first heated on a galette with a temperature T ranging from 80 to 145 ° C and then subsequently heated in a draw-off ejector to T2. achieve the greatest decrease in shrinkage forces, ranging from 110 to 160 ° C, depending on the type of polypropylene conjugated fibers used.

The time course of the precipitation forces shows a maximum at a certain temperature level within the heating period of up to 1 minute. Here, a warm-up time of 20 to 30 seconds is important, in which a rapid rise and then a rapid decrease in relaxation forces occurs, as shown in the drawing. The heating of the fiber on the second gravel with a temperature of Ti in the range of 80 to 145 ° C provides better fiber stabilization characterized by the reduced level of linear shrinkage that is required for most textile applications. The temperature T2 is set to heat the air to the draw-off ejector in the temperature range from 110 to 160 ° C, which draws the fiber from the sinking galette and feeds it into the refiner, where the fibers are freed in the free state.

The process according to the invention can be applied in an aggregated dredging process or else in a continuous spinning and dredging process.

Further advantages of the method of enhancing the polypropylene conjugated fibers of the invention are apparent from the following examples.

Example 1

From the graphical recordings of the evaluation of the loaded polypropylene fiber of 330 dtex fineness on a contraction meter, it was found that the greatest difference in the coagulation forces of 16 cN was reached at 130 ° C for a period of 20 seconds. The temperature of the hot air in the draw-off ejector nozzle of 130 degrees Celsius was set to increase this fiber. The speed of the gravel was 1,350 m / min, 20% relaxation. Achieved level of flaking at 6.4% / cm with a linear shrinkage of 16.1%. When refined with heating of the second surviving galet after being heated to 100 [deg.] C., the flanging remains at a level of 6.6 obl./cm, but the shrinkage decreases linearly to 9.9%.

Example 2

According to the evaluation of the sintered conjugate fiber of 1320 dtex, it was found that at 145 ° C the difference in clotting forces after 20 seconds was 70 cN.

The softening was carried out at a hot air temperature in the draw-off ejector nozzle of 145 ° C. A speed of 1,650 m / min, with a 3.0 ratio. Winding speed 1,290 m / min. Achieved fiber filament level of 10.1 vol / cm and linear shrinkage of 17.1%.

The relaxation level will be 24.8% when softening and heating the second gravel to 120 ° C.

Fiber properties; 8.7% / cm, linear shrinkage 5.5%.

Example 3

Similar to Examples 1 and 2, it was found that at a temperature of 160 ° C the greatest decrease in clotting forces of 40 cN was achieved. Concentration of the conjugated fiber 880 dtex was performed at a flow rate of 2175 m / min, with a grain ratio of 2.8 at 70 ° C. At a draw-off speed of 1,850 m / min, the relaxation was 15%.

Properties of prepared fiber; 7 obl./ / cm, linear shrinkage 15 ° / o.

Claims (1)

SUBJECT A method of expanding polypropylene conjugated fibers which are heated and expanded upon stretching, characterized in that the conjugated fibers are first heated on a galette having a temperature in the range of 80 ° C to 145 ° C and then subsequently heated to a temperature in hot air. wherein the fibers achieve the greatest decrease in shrinkage forces in the range of 110 ° C to 160 ° C, depending on the type of polypropylene conjugated fibers used.