US3553803A

US3553803A - Process and device for crimping and heat-setting of yarns made from synthetic linear high polymers

Info

Publication number: US3553803A
Application number: US788845A
Authority: US
Inventors: Gerhard Buschmann; Erich Mewes
Original assignee: SCHWARZA CHEMIEFASER
Current assignee: SCHWARZA CHEMIEFASER; VEB CHEMIEFASERKOMBINAT WILHELM-PIECK-STADT GUBEN
Priority date: 1969-01-03
Filing date: 1969-01-03
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

PROCESS AND DEVICE FOR CRIMPING AND HEAT-SETTING OF YARNS MADE FROM SYNTHETIC LINEAR HEATER HIGH POLYMERS, ESPECIALLY POLYAMIDES AND POLYESTERS, WHICH COMPRISES EXTENDING THE PATH OF THE YARN BETWEEN THE STRETCHING ZONE AND THE ENTRANCE TO THE CRIMPING ZONE WHILE REDUCING THE HEAT DEVELOPED IN THE STRETCHING OPERATION, THEREAFTER SUBJECTING THE YARN TO COMPRESSION CRIMPING AND HEAT-SETTING THE CRIMPED YARN RELEASED FROM THE CRIMPING ZONE IN A TWO-STAGE OPERATION IN SUBSEQUENT STEPS AT CONTROLLED TEMPERATURES.

Description

Jan. 12, 1971 G. BUSCHMANN ETAL 3,553,803

PROCESS AND DEVICE FOR CRIMPING AND HEAT SETTING OF YARNS I MADE FROM SYNTHETIC LINEAR HIGH POLYMERS Filed Jan. 5, 1969 1 INVEN'TOR GERHARD BUSCHMANN ERICH MEWES ATTORNEYS United States Patent 3,553,803 PROCESS AND DEVICE FOR CRIMPING AND HEAT-SETTING OF YARNS MADE FROM SYN- THETIC LINEAR HIGH POLYMERS Gerhard Buschmann and Erich Mewes, Wilhelm Pieck Stadt Guben, Germany, assignors t0 VEB Chemicfaserkombinat Wilhelm-Pieck-Stadt Guben, Wilhelm Pieck Stadt Guben, Germany Filed Jan. 3, 1969, Ser. No. 788,845 Int. Cl. D02g 1/12 US. Cl. 281.6 6 Claims ABSTRACT OF THE DISCLOSURE Process and device for crimping and heat-setting of yarns made from synthetic linear heater high polymers, especially polyamides and polyesters, which comprises extending the path of the yarn between the stretching zone and the entrance to the crimping zone while reducing the heat developed in the stretching operation, thereafter subjecting the yarn to compression crimping and heat-setting the crimped yarn released from the crimping zone in a two-stage operation in subsequent steps at controlled temperatures.

Crimping processes for yarns made from synthetic fibers are already known having the object of imparting to the smooth yarn a wool-like texture, an increased fullness, and a higher resilience. The expression yarn used herein is intended to include monoas well as multifilament products. The above mentioned object is accomplished by causing the yarn to pass into a crimping chambet at relatively high speed and by pressing the yarn onto a plug already present in the chamber. The bending in this procedure occurs in a preferred direction, but this does not exclude the bending from occurring in any other direction. The introduction of the yarn into the crimping chamber may be effected by pneumatic, hydraulic, or mechanical devices.

At any rate, the yarn entering the chamber has to be heated before introduction. The heating may be brought about by heating rails, or other heating elements, operated by steam, hot gases, liquids, electrical resistance or induction, or in any other desired manner.

Some crimping devices are further known which are of the compression chamber type, in which immediately before the crimping a stretching of the yarns occurs and wherein the resulting partial successive softening of the yarn is made use of in the crimping process, so that a pre-heating of the yarn may be dispensed with.

The yarn entering the crimping chamber may already have a preliminary twist, because this will yield a closed bundle of thread which passes through the chamber more smoothly than an untwisted fiber. The preliminary twist may already be present on the yarn discharge device, or it may be brought about by means of rotating devices while the yarn is drawn off said device. The latter device and method of operation may be more desirable, since it permits satisfactory handling of the yarn discharge device as well as favorable conditions for the yarn for entering the crimping chamber.

For improving the degree of heating-setting of the crimped yarn, there are devices known in which threads are after-treated in stabilizing chambers arranged in series with the crimping chamber; there, treatment is effected with hot or cold agents. When heat-setting is done in the crimping chamber, either direct or indirect heating means may be used. In both cases steam, liquid or gaseous heating media or electric energy can be used. The same direct or indirect heating means can be employed when the heatsetting is effected in the stabilizing chambers. It is also Patented Jan. 12, 1971 known to cause the textured yarn to pass heating and cooling zones arranged directly in series.

Another known means for setting the unset, textured yarn leaving the stabilizing chamber is the use of heating bars or rails or similar devices; this method is used for obtaining a lasting crimp and for obtaining threads of uniform physical characteristics to improve dyeing properties and decrease the tendency of shrinking.

However, the known processes and devices have the drawback that they do not lend themselves for the production of yarns having a predetermined crimping degree, which is necessary for the subsequent processing in different sectors of the industry. For application in various fields, a graded degree of crimping is required. Thus, for instance, the rug manufacturers ask for a low crimp, the manufacturers of materials for furniture coverings request a higher crimp and the manufacturers of knitted fabrics for wearing apparel ask for the highest degree.

Moreover, the degree of heating-setting accomplished up to now is not satisfactory in some cases, so that upon further processing considerable difiiculties are encountered, such as excessive shrinkage, or extension of the crimped yarn during dyeing and winding on reels.

It is an object of the present invention to provide a process and device which will eliminate the short-comings of the known methods and devices.

More particularly, it is an object of the invention to provide means whereby the degree of crimp of the fibers processed is variable within a certain range and will favorably affect the further processing in different fields of application.

Other objects and advantages of the present invention will become apparent from the following detailed description in combination with the accompanying drawing.

For a better understanding it should here be noted that by the degree of setting of the crimped yarn we mean to indicate a means of measuring the degree of orientation of the molecules in the direction of the thread and for the inner structure of the thread. On the other hand, the degree of crimping defines a ratio of lengths of sections of the thread under tension and without tension, when loads are applied which depend on the thickness of the thread in each case. The degree of crimping is influenced positively by the choice of the temperature to which the yarn is preheated before entering the crimping chamber.

In accordance with the invention it was found that a graded adjustment of the degree of crimping can be travelled by the yarn between the stretching and the crimping, while decreasing the heat of stretching by inserting an appropriate device for adjustably lengthening the path; such a device may eg be :a guide roll for changing the direction of the travelling yarn. The change of the path may be in stages or occur without interruption. The latter may be brought about by slidably arranging the guide roller for instance in a slot.

For the improvement of the setting, the arrangement according to the invention provides that the crimped yarn leaving the crimping chamber is treated in a receiving chamber directly following the crimping chamber, while relieved from stress; the treatment is performed with a suitable heating agent, preferably steam, which will cause shrinkage and heat-setting. The heating agent is fed into the device about at the transition zone between crimping chamber and receiving chamber. In order to increase uniformity and stabilization of the desired setting, the treat ment in the receiving chamber will be followed by aftersetting in a heating device, preferably heating rails, bars or heated godets. By selecting the desired temperature of this heating device and by changing appropriately the time while the crimped threads are made to stay on the heated surfaces, an accurate adjustment of the degree of setting can be achieved.

The invention has extended the field of application of compression-crimped yarn to an unexpected degree. For instance, in the manufacture of knitted goods there is a far wider applicability. The suggested lengthening of the path of the yarn, particularly the combination of the last stretching godet with a guide roller on which the yarn is repeatedly wound, has the added advantage that variations of the speed of travel within the stretching field are avoided which in turn eliminate fluctuation in the thickness of the crimped yarn.

The better setting of the crimp is also an important improvement of the product and an advantage for the industries concerned.

The invention will now be explained in an example with reference to the accompanying drawing, the sole figure of which schematically illustrates a device for carrying out the process according to the invention.

In the drawing, a spool 1 is shown on which a yarn 13 is collected and from which it is withdrawn by a pair of rollers 6; arranged in its path are a guide roller 14 and two

stretching godets

2 and 3, the latter being rotated at a higher speed than the former. The yarn is next passing a deflecting roller 4 and from there reaches a funnel 5 at the entrance of the crimping chamber 7 of known design. The deflecting roller 4 is mounted on a plate 19. The shaft (not shown) of the roller 4 is supported in a slot 18 in the plate 19. The roller 4 may be set at any point along the slot 18 and, when desired, adjusted to a new position along the slot 18. Crimping occurs by compression of the yarn against a flap which defines the downstream end of the crimping chamber 7. The flap 15 is rigidly connected to a lever 16 and this assembly is pivotally mounted to the wall of the crimping chamber 7 at the juncture of the flap 15 and the lever 16. A weight 17 suspended from the free end of the lever 16 maintains the compression in the crimping chamber.

As shown in the drawing, the yarn 13 can be wound around the deflecting roller 4 and the godet 3 several times in a predetermined manner whereby the length of the path traversed and the cooling of the yarn are controlled and thereby the crimp accomplished is likewise determined. Typically, distance between godet 3 and roller 4 is about cm.

The crimping chamber 7 is followed by a receiving chamber 8 of larger cross section so that the stack of yarn leaving the crimping chamber under pressure can then expand.

In the state of pressure relief, the crimped stack is treated with a suitable heating agent, for instance steam, admitted through a conduit 9; the yarn is thereby subjected to shrinkage and becomes set. The crimped, shrunk and set yarn is then withdrawn from the stack over a tensioning device 10 and passed over another heating device 11 before being wound onto a spool 12; by the passage through the heater 11, and after-setting of the yarn takes place. The temperature in the heater 11 should exceed that in the receiving chamber 8. When polyamides are thus treated, the yarn temperature in the chamber 8 should preferably be from to 140 C. and the yarn temperature at heater 11 should preferably be from to 180 C. and should not exceed 190 C.

What is claimed is:

1. A process for crimping and heat-setting yarns made from synthetic linear high polymers, which comprises variably lengthening the path of the yarn between a stretching zone and the entrance to a crimping zone for reducing the heat developed in the stretching operation, thereafter subjecting the yarn to compression-crimping in the crimping zone, and heat-setting the crimped yarn released from the crimping zone in a two-stage operation at controlled temperatures.

2. The process according to claim 1, wherein the temperature in the first heat-setting step is lower than the temperature in the second heat-setting step.

3. The process according to claim 2 which comprises subjecting polyamide yarn to the crimping and heat-setting operations and maintaining the temperature in the first stage at 105 C. to C. and in the second stage at 120 C. to C.

4. A device for crimping and heat-setting yarn made from high-molecular weight linear synthetic polymers which comprises a crimping chamber, a receiving chamber arranged in series therewith, means for feeding said yarn from a source into saitfcrimping chamber, at least one stretching roller in the path of said yarn between said source and the withdrawal means, a direction changing deflecting guide roller between the stretching roller and the Withdrawal means, said stretching roller and said guide roller serving for variation of the path length traversed by said yarn so as to dissipate some of the heat developed therein during the stretching operation, first heating means near the outlet of the crimping chamber, second heating means arranged in the path of the yarn traversed after the receiving chamber, and final spooling means for said yarn, said heating means acting as heatsetting means for the crimped yarn.

5. The device according to claim 4, wherein the stretching means consists of a plurality of godets, the last godet together with said deflecting guide roller capable of receiving the yarn in a number of turns for varying the length of the yarn path traversed before the yarn arrives at the crimping chamber and thereby the degree of crimp effected in the yarn.

6. The device according to claim 4 wherein said first heating means consists of steam and said second heating means consists of an electric heating device.

References Cited UNITED STATES PATENTS 3,425,106 2/1969 Mattingly 28-1.6 3,441,989 5/1969 Clarkson et al 281.6

LOUIS K. RIMRODT, Primary Examiner U.S. Cl. X.R. 2.872.14