DD301552A7 - METHOD FOR PRODUCING FIBERS FROM POLYAETHYLENEPEPHTHALATE WITH LOW RESTRICTION AND HIGH STRENGTH - Google Patents

Abstract

The process is used in the production of polyester fibers for their post-treatment. Conventionally spun synthetic polyethylene terephthalate threads are aftertreated by a combined stretching, fixing and relaxation process to give fibers of high strength and low shrinkage, which are easily processed into rigid products on a high performance machine using a defined finish preparation. org .; Polyester; polyethylene terephthalate; Post-treatment, chemical; stretching; Fix; relax; Thread; Shrink; Prepare; Preparation; Textile auxiliaries; finishing agent; avivage; surfactants; Equip; Lubricant}

Description

Field of application of the invention

The invention relates to a process for the preparation of spun by the conventional melt spinning process synthetic fibers of polyethylene terephthalate with low residual shrinkage, especially low Thermosch.'umpf and high strength.

Characteristic of the known technical solutions

It is well known to produce high strength and low elongation fibers by a multi-stage stretching process in which the preoriented spinning material is stretched to the limit. It is irrelevant whether the spinning material has been spun conventionally or by the high-speed spinning process.

However, the fibers or silks thus produced have the disadvantage that they still have a very high residual shrinkage (Thormoschrumof at 200 ° C S 10%).

These values are also sufficient for most textile processing technologies and applications.

Increasingly, however, there is the requirement of processing Industi ie for fibers of polyethylene terephthalal with low thermal shrinkage (<2% at 170 ° C, <3% at 200 ⁰ C) for the production of products that exposed to elevated temperatures in their processing or their application are, but have to remain extremely dimensionally stable. Examples of such applications of high strength and low shrinkage fiber are sutures and industrial fabrics.

The production of low-shrinkage polyester fibers and silk has been known for some time.

The simplest way to obtain such fibers is to allow the stretched material to shrink freely at or above the temperature it is later exposed to.

In DE-OS 2134500 done by contact with hot air, in DE-OS 1435396 the use of a hot üntspannungsplatte is described.

Although very good thermal shrinkage values are achieved with these processes, as a result of free shrinkage over a long period of time, there is a sharp increase in fiber fineness combined with a marked drop in strength and an increase in the surface oligomer content, making textile use of the fibers almost impossible.

In DE-OS 1 934 644 a heat treatment process is described in which at least one intermediate heat treatment stage is switched on before a relaxation stage. With this method also very good thermal shrinkage words can be obtained with reasonable fiber strength. Due to the high thermal load but a deterioration of Kräuselungsbereitschaft i.'in, so that the fibers no longer required for processing on high-performance machines crimping image can be impressed.

DE-PS 2318887 and DD-AP 94055 describe processes for the production of high-strength, low-shrinkage polyester yarns by the high-speed spinning process. With 80 to 160 ⁰ C very high temperatures are used to carry out the stretching process. In a heat treatment step, at temperatures near or above the melting point of the polyester, the preparation for the relaxation process takes place, which is triggered in a separate step on a godet or pair of godets, without supply of energy and with defined voltages.

In DE-PS 2318887 eiri method is described, after which in addition a heated trigger member is required, which must deduct the threads from the draw zone and heat as a precursor to relaxation.

Because of the high temperatures and speeds or the very low stresses, these conditions can not be transferred to conventionally-stretched synthetic filaments with high cable thicknesses, since melting, capillary breakage and winding formation and thus high productivity losses occur.

In addition to the crimping, the preparation has a great influence on the processing properties of the fibers. It is known to use phosphoric acid ester compounds as thermostable fiber preparations.

The reaction products of Phosphorpentoxidmitoxäthylierten fatty acids (DE-OS 2658862) or phosphorus pentoxide with oxyethylated fatty alcohols (DE-AS 2134854, GB-PS 1042904) give the fibers a favorable dynamic fiber / metal and static fiber / fiber friction behavior and thus good Verarboitungseigenschaften. However, due to the oxyethylated portions, they cause unwanted increased migration of oligomers to the fiber surface during thermal treatment of the fibers (eg, fixing, dyeing).

On the other hand, the reaction products of phosphorus pentoxide with fatty alcohols do not exhibit this property, but experience has shown that these polyester fibers, which are conventionally prepared conventionally and do not dynamically flatten the products, can not be satisfactorily processed (Kleber, R. Meüiand Textilberichte, 10, 1980, P.831 ff).

Object of the invention

The object of the invention is to post-treat conventionally spun synthetic polyethylene terephthalate threads by a combined insertion, fixing and relaxation process in such a way that fibers having a crimping, high strength and low residual shrinkage required for the respective field of application are obtained, using a defined finish preparation Can be processed without difficulty on Hochloiotungsmaschinenen to formstebilen products.

Explanation of the essence of the invention

The invention is based on the object according to the conventional melt spinning spun and tufted synthetic polyethylene terephthalate so that the required fiber values, high strength, low residual shrinkage and crimping, and good processing properties by a technologically specific driving the drawing in conjunction with the drawing temperature and Drawing tension and a hydrothermal and preparative treatment can be obtained.

According to the invention, this is achieved by first stretching a filament tow having a total thickness of 30 to 120 ktex in two stages. In the first stage, the drawing is carried out on heated godets to natural draw ratio beieinerTemperaturTg -5 ⁰ C to Tg + 5 ⁰ C (Tg = glass transition temperature of 2nd order). In derzwoiten stage, the fiber is post-stretched in a water bath at a temperature of 10 to 25 ⁰ C above Tg by 5 to 20% and squeezed to a moisture content of 10 to 20%. The yarn sheet is without further thermal intermediate treatment stage on a Walzenfixieraggregat in Einlaufgalettensystem at a temperature of 20 to 6O ⁰ C below the melting point of polyethylene terephthalate under hydrothermal conditions at a tension of 2 to lOp / tex by 6 to 10% and in the Auslaufgalettensystem at the same temperature, but in the absence of moisture, relaxed by a further 4 to 8%.

It is crucial for the fiber properties that the relaxation ratio of the group of yarns between the discontinuous godet system and the in-feed godet system is less than or equal to 1, preferably 0.7 to 0.8.

The fibers are, after the fixation / relaxation process, finished with an alkylphosphoric acid ester product as finish preparation, preferably consisting of a condensation product of phosphorus pentoxide and C, 2-C, _4- alcohols, the ratio of monoester: diester being 60:40 to 40:60 and the tertiary group is present as the potassium salt.

Preferably, this product is applied as an aqueous emulsion to the fiber, the preparation pad is at least 0.03%.

After the finishing equipment, the yarn sheet is crimped, dried and cut.

The value of the Entkräuselung is at least 18%, and div. Drying temperature is not above 100 ⁰ C.

Ausführungsboisplöl

Polyäthylvsnterophthalatschmelze with a temperature of 295 ⁰ C is pressed in a spinline through 18 nozzles with 1300 holes and a flow rate of 630g / min per nozzle, withdrawn at 1200 m / min, bofeuetuat and placed in a pot. The filament count of the finished fibers is 0.13tex. 10 pitchers become an elementary filament! from 30ktex, which in the first stage is stretched to 3.50 times on a drafting machine with 7 heated godets at 68 ° C. In the second stage di.3 cable W 'Sserbad is at 85 ⁰ C nachver treckt and squeezed by a further 13% by Quctschwalzenpaarauf a moisture content of 16%.

With a discharge speed of 100 m / min from the squeeze roller pair, the cable enters a 3-roller mill without further heat treatment and has a surface temperature of 220X. In the run-in godet system, the yarns are allowed to relax by 8% under hydrothermal conditions at a tension of 3p / tex and by 6% in the godet system under the same purely thermal conditions in the absence of moisture.

The relaxation ratio of the F.ir 'ischar between the outlet and inlet godet system is 0.75.

The thus-treated tow is passed through a spin finishing bath consisting of a 1% aqueous emulsion of a condensation product of phosphorus pentoxide with C ₂ - is C ₁₄ alcohols, wherein the ratio Monoester: diester is 60:40 and the tortiäro group is present as the potassium salt.

The filament tow is then crimped, dried at 8O ⁰ C within 10 min and cut to a staple length of 38mm.

-3- 301

The fibers produced according to the invention are characterized by the following properties:

Filament unit: 0.131 tex

Yield strength: 584mN / tex

Elongation at break: 21%

Hot air shrinkage (170 ⁰ C, 10 min): 1.1%

Hot air shrinkage (200 ⁰ C, 10 min): 2.1%

Boiling shrinkage: 0%

Preparation dressing: 0.09%

Shrinkage: 26.4%

They can be easily processed on card, track, flyer and ring spinning machine into yarns, from which high-quality, dimensionally stable sewing threads are produced.

Claims (3)

1. A process for producing fibers of polyethylene terephthalate with low residual shrinkage and high strength by aftertreatment conventionally spun and gefachter threads, characterized in that the filament tow in the first stage at a temperature Tg -5 ⁰ C to Tg +5 ⁰ C until stretched in the second stage at a temperature of 10 to 25 ⁰ C above Tg in a water bath by 5 to 20%, squeezed to a moisture content of 10 to 20% and fed without further thermal intermediate stage a Walzenfixieraggregat on which the cable at a temperature of 20 to 60 ⁰ C below the melting point of polyethylene terephthalate in the inlet godet system under hydrothermal conditions at a tension of 2 to 10p / tex by 6 to 10% and in the outlet galettensystem at the same temperature, but in the absence of moisture for another 4 bis 8% relaxed, then with an aqueous emulsion an alkylphosphoric acid ester finish and crimp, dry and cut in a known manner. 2. The method according to claim 2, characterized in that the relaxation ratio of the yarn sheet between the outlet and Einlaufgalettensystem ^ 1, preferably 0.7 to 0.8. A process according to claims 1 and 2, characterized in that the alkylphosphoric acid ester is a condensation product of phosphoric acid pentoxide with C _ir -C ₁₄ alcohols, the monoester-diester ratio being 60:40 to 40:60 and the tertiary group being potassium salt ,