Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1999-07-23
2002-07-30
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S375000, C428S377000, C252S008620, C264S210800
Reexamination Certificate
active
06426141
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a high-speed false twist texturing process for yarns of synthetic filaments and to the use of a certain finish for this texturing process.
2. Discussion of Related Art
Since the beginning of the eighties, fine bulky polyester yarns (PES) for such applications as clothing or furniture covering materials have mainly been produced by the so-called POY (partially oriented yarn) spinning process followed by false twist stretch texturing.
In false twist stretch texturing, a PES-POY yarn is simultaneously stretched and bulked. The bulk is imparted by intensive twisting of the yarn in its plastic state followed after cooling by untwisting. The plastic state of the yarn is achieved by passing the yarn over a contact heating rail. The twist is mainly imparted by ceramic or polyurethane friction disks (twisting unit). In recent years, the speed of false twist stretch texturing (FT) has been steadily increased (an explanation of the basic principles can be found in H. K. Rouette, Lexikon der Textilveredlung, 1995, pages 1524 to 1531 and 2180 to 2183). Up to the mid-nineties, speeds of 700 m/min to 900 m/min were normal for standard yarns. To achieve these speeds, it had become necessary to use very long heating rails (>2.5 m) generally heated with diphyl. The cooling rails also had to be increased in length to more than 1.5 m. The machines were correspondingly large and difficult to operate. At the beginning of the nineties, false twist stretch texturing machines that were far more compact thanks to the use of novel heaters appeared on the market. The length of the filament path in these machines is distinctly reduced which reduces the buildup of tension and creates the potential for increased speeds. In contrast to traditional contact heaters, of which the temperatures were between 180 and 230° C., the new heaters operate with virtually no contact, but with temperatures of >500° C. By virtue of the very high temperatures, the new heaters could be reduced in length to around 1 m. Although the maximum speed which the generation of high-temperature machines is capable of reaching is generally 1500 m/min., it has been found in practice that speeds of 900 to 1,000 m/min. are rarely exceeded. The reason for this lies in the extremely high yarn breakage rates which occur at higher speeds. It is known that the increase in yam breakages is generally preceded by a proliferation of yarn tension peaks. Accordingly, there is an urgent need for PES-POY yarns which can be processed in the new high-temperature heater texturing machines with a distinctly reduced tendency towards tension peaks and hence to breakages.
Besides improvements in the yarns and the spinning process, the finishes which have to be applied to the yam during spinning and which mainly have a lubricating effect were also looked at with a view to optimization. EP 826 816 A2, for example, describes finishes for use in the false twist texturing of synthetic yarns which contain certain polyether compounds mixed with cyclic polyorganosiloxanes in selected quantity ratios. However, even with these finishes, it is only possible to achieve speeds of up to 1,000 m/min., especially because at temperatures of 350° C. to 500° C. polysiloxanes are thermo-oxidatively degraded to hard silicate deposits on the yarn guides of the high temperature heaters.
The problem addressed by the present invention was to provide finishes for the false twist texturing of synthetic yarns which could even be used under high-speed false twist texturing conditions, particularly in texturing machines with short high-temperature heaters, and which would substantially reduce the number of yarn breakages.
It has now surprisingly been found that the addition of a selected water-insoluble low-viscosity component to lubricants known per se leads to finishes which meet the desired requirement profile.
DESCRIPTION OF THE INVENTION
In a first embodiment, the present invention relates to a process for the texturing of yarns of synthetic filaments in which a finish containing at least one water-soluble lubricant (A) and one water-insoluble liquid (B) with a viscosity of 2 to 50 mPas at 20° C., as measured in accordance with DIN 53015, and optionally emulsifiers and/or wetting agents and other auxiliaries is applied to the yarns in the form of an aqueous emulsion, after which the filaments are textured on the false twist principle in a machine with a short high-temperature heater.
The water-insoluble component (B) is distinguished in particular by its viscosity behavior. Preference is attributed to low-viscosity liquids with a viscosity in the range from 2 to 50 mPas, preferably in the range from 2 to 30 mPas and more particularly in the range from 5 to 25 mPas, as measured at 20° C. in accordance with DIN 53015 using a Höppler viscosimeter. Water-insoluble components (B) with a viscosity of 5 to 10 mPas are particularly advantageous.
Corresponding liquids are selected, for example, from the group of water-insoluble esters of fatty alcohols containing 16 to 24 carbon atoms and/or polyols containing 2 to 6 carbon atoms and 2 to 6 hydroxyl groups with linear or branched, saturated or unsaturated C
6-22
fatty acids. Suitable fatty alcohols are, for example, palmityl, stearyl, arachidyl or behenyl alcohol. Suitable fatty acids are, for example, caprylic, pelargonic, capric, undecanoic, tridecanoic, myristic, pentadecanoic, palmitic, heptadecanoic, octadecanoic, nonanoic, arachic or behenic acid. Suitable polyols are, for example, glycol, diethylene glycol, glycerol, trimethylol propane or pentaerythritol. The polyols may be completely or partly esterified. The crucial factor is that the compounds should be insoluble in water and, at the same time, should satisfy the viscosity criterion mentioned above. Water-insoluble compounds in the context of the present invention are compounds of which at most 5% by weight and preferably at most 1% by weight dissolves at 20° C. Particularly preferred water-insoluble compounds are esters of branched-chain alcohols obtainable, for example, by Guerbet or oxo synthesis with fatty acids, for example esters of 2-ethylhexyl alcohol with C
16-18
fatty acids, such as 2-ethylhexyl stearate. Linear fatty acids of this cut are particularly preferred. Besides these long-chain esters, methyl esters of linear or branched, saturated or unsaturated C
8-22
fatty acids are suitable liquids of type (B). Dicarboxylic acid esters, such as diisooctyl sebacate, diisotridecyl sebacate and diisooctyl esters of azelaic acid, and the water-insoluble reaction products of these compounds with ethylene oxide and/or propylene oxide may also be used as the liquids (B). Water-insoluble esters of thiodipropionic acid, for example with 2-ethyl hexanol, decanol or isotridecyl alcohol, and the water-insoluble reaction products of these compounds with ethylene oxide and/or propylene oxide are also suitable as are the water-insoluble esters of glycol, diglycol or triglycol with C
8-22
fatty acids and alkoxides thereof.
Other suitable compounds for the liquids (B) are alkoxylated fatty acid esters corresponding to formula (I):
R
1
—COO—(C
n
H
2n
O)
m
—R
2
(I)
where R
1
is a linear or branched, saturated or unsaturated C
7-21
alkyl group, R
2
is a linear or branched, saturated or unsaturated C
1-12
alkyl group and n is the number 2 or 3 and m is a number of 1 to 10 and preferably 1 to 6. Particularly preferred compounds of formula (I) are those in which R
2
is a short-chain alkyl group containing 1 to 4 carbon atoms. The alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, esters may be obtained by known methods, more particularly in accordance with the teaching of WO-A-90/13533. In the case of mixed alkoxides, the alkoxylation may be carried out in random or block form.
Water-insoluble low-viscosity liquids from the class of symmetrical or asymmetrical dialkyl ethers preferably containing a total of 12 to 44 carbon atoms, for example dioctyl ethers, didecyl ethers or
Bialas Norbert
Lippman Andreas
Mathis Raymond
Cognis Deutschland GmbH & Co. KG
Drach John E.
Gray J. M.
Kelly Cynthia H.
Murphy Glenn E. J.
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