DE2611766A1 - METHOD FOR MANUFACTURING A CURLED YARN AND THE PRODUCT SO MANUFACTURED - Google Patents

Description

Pie invention relates to a method for making a crimped or after relaxation of crimpable filament yarn made of a polymer based on ethylene terephthalate.

From "British Patent 911 509 it is known crimped Yarns by drawing at least 3 times an undrawn or to produce partially drawn polyamide yarn, the yarn at the drawing point being perpendicular to its longitudinal axis exhibits a temperature gradient which, however, is not caused by contact with a hot surface. According to this Patent specification is a yarn with high crystallinity, low orientation and a birefringence not exceeding 0.012. However, this procedure is complicated because of the numerous temperature controls involved, so that work is not carried out at high speed can be.

British Patent 1,025,241 also discloses a process for the production of crimped filaments from polyethylene terephthalate by drawing undrawn filaments having a birefringence of 0.001 to 0.015 in a drawing ratio from 2.5 to 6 times known, in which a transverse tension gradient due to friction of the yarn with at least a quarter turn and up to 4 turns on an intermediate

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See the pin attached to the delivery and the drawing rollers with a radius below β mm, while the temperature of the yarn is ^{brought to 90 to 125 0} C immediately in front of the pin, which is also heated, and consequently the temperature of the filaments is practically over their entire cross-section is even.

However, the curl is insufficient when at high speed is operated, and this procedure requires the setting of two temperatures.

Finally, from the French patent 1 243 781 is a process for the production of yarns with latent crimp by asymmetrical heating on a narrow surface heated to 300 to 90O ⁰ C during drawing with a drawing ratio of 2 to 8 times at a speed of at least 100 m / min, known, whereby the yarn experiences a change of direction at an angle of 130 to 170 ° on the hot surface between its point of arrival and departure. However, this method is difficult to use because the temperature of the pin is well above the melting point of the yarn and the crimp is not latent.

\ gekrauseIten or _r The invention relates to a method for producing einesVnach relaxation crimpable yarn made of polyester based on ethylene terephthalate, which is characterized in that a yarn made of homo- or copolymer based on ethylene terephthalate having a birefringence 0.015 to 0.080, a boiling water shrinkage of $ 25 to $ 80 and a crystallinity of not more than $ 6, is subjected to stretching at a stretch ratio such that its elongation can be reduced to below $ 15 after stretching, this stretching in one place is located where the yarn has a temperature gradient across its cross-section, which is caused by a short run of the yarn over a solid, polished, convexly curved organ on which a 2 to 30 ⁰ C below the melting point of the polymer

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low temperature is maintained, "is effected.

The invention also relates to that obtained by this process Yarn that can be crimped cold after relaxation.

The method according to the invention is applied to a yarn made of polyethylene terephthalate or from a polymer! applied, which consists of a high proportion of ethylene terephthalate units and a low proportion Proportion of units is made up of another diöl as ethylene glycol or any aromatic diacid other than terephthalic acid. This yarn should also be a Birefringence of 0.015 to 0.080, but preferably between 0.030 and 0.070, a boiling water shrinkage from $ 25 to $ 80, preferably between $ 40 and $ 80 and one Crystallinity of not more than $ 6, but preferably less than $ 3, and if possible, equal to or close to zero. Such a yarn is generally produced by spinning at a speed of 2000 to 4000 m / min and has generally a residual stretch of about 1.4 to 2.5 times at ordinary temperature.

In the following text, "residual stretching", unless otherwise stated, is to be understood as the stretching which the Yarn can learn to have an elongation of $ 25.

Under the conditions of the present invention, this yarn is subjected to a drawing which causes its elongation can be reduced to less than $ 15, but preferably less than $ 10 after stretching. To this end, will drawn with a draw ratio which is above the residual draw of the yarn after spinning, the difference being between the stretching ratio used in the process according to the invention and the remaining stretching in general about 1/10 to 1/4 of the latter.

The actual drawing is localized at a point where the yarn receives a temperature gradient across its cross-section. For this purpose, between the delivery and the

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Streckwalzeii a solid, polished, convexly curved organ is attached, on which a temperature is maintained which is 2 "to 30 ⁰ C below the melting point of the polymer forming the yarn, but preferably 2 to 8 ⁰ C below this point, for example at 250 ⁰ C. This element can be a cylindrical pin or any other convex curved surface, but surprisingly it does not necessarily have to have a very small radius of curvature. The contact of the yarn with this element must be sufficient to maintain the temperature of the yarn on one side of the yarn However, it must not take too long so as not to heat the yarn. In this way, a strong temperature gradient is created over the cross-section of the individual filaments of the yarn. The contact length naturally changes with the running speed of the yarn a stretching speed of about 600 to 700 m / min, a contact length of about 11 mm in general, while b At a stretching speed of 6000 to 7000 m / min, the contact length must be significantly greater and can range up to 400 mm and more.

The yarn thus obtained has good crimp properties, in particular a very fine spiral ripple as soon as it is relaxed in a cold, but preferably in a hot state. The yarn can open immediately after the process according to the invention Stretching can be wound onto cops under tension. It then looks like a flat yarn, but it starts to pucker, as soon as the tension ceases, e.g. when unwinding at normal temperature. However, the curl is all the finer the faster the relaxation occurs after stretching. she is also the finer and more permanent, the higher the temperature is during relaxation.

It is therefore advantageous to continuously relax the yarn immediately after it has been stretched. These Relaxation can be done by any known method, e.g., by temporarily storing the yarn without any tension at ordinary temperature or in the warmth. It can be carried out in particular with the help of the gate direction

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in DOS 2 419 298 and into which cold air, hot air, steam or a mixture of hot air and steam at temperatures of 180 ^° C. and more, but preferably from 120 to 180 ^° C., can be introduced. In order to wind up the yarn without tension in order to maintain the crimp, the nozzle can be directed vertically (or upwards at a small angle to the vertical and extended by a tube going in the same direction, so that the yarn is supported as it exits the nozzle .

It is also possible to use a nozzle as described in DOS 2 450 074, onto which a pipe or a second nozzle, working in the opposite direction, follows to support the yarn in the space between the two nozzles.

The process according to the invention can either be carried out on a previously spun and wound yarn or directly and continuously following the spinning process without intermediate winding be applied. In the first-mentioned Pail can for the invention Procedure the optimal speed can be chosen, which ensures the proper operation of the device used enables. In the second pail, the speeds should be chosen in such a ratio that one both a yarn with good characteristics as well as a flawless operation of the integrated process is obtained. Such an integrated The process is by far the most economically advantageous because one goes directly from the molten polymer to the curled, can get on the textile fabric usable yarn.

The yarn made according to the present invention has a fine crimp and good extensibility and crimp characteristics. The pilaments are not deformed in cross-section and show no traces of melting on the surface. The inventive The process is therefore very gentle on the yarn and, in contrast to most known processes, does not have any significant effect Pestilence losses.

According to an interesting variant of the inventive method

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driving it is possible to get a fancy blended yarn by that the bundle of pilaments is divided into two bundles as it emerges from the spinneret, one of which is the one according to the invention Stretching process, but the other is subjected to a simple stretching process without asymmetrical heating whereupon both bundles are reunited, e.g. with the help of an entangling nozzle. One receives thereby on very economical way a mixed yarn with a very good fantasy effect.

Surprisingly, it is found that crimp can only be obtained by using the process of the invention applies to yarns that simultaneously show values for birefringence, boiling shrinkage and crystallinity, which are all within the limits given above. ! However, if only one of these values is outside the stated Limits, the yarn will not pucker even if one tries to use the treatment conditions as in Examples 1, 2 and 12 to be changed. Crimping therefore takes place all the less when two or more of these values are outside of those according to the invention indicated limits, as is the case in Examples 7 and 14 to 17 with respect to various polyamides.

The attached drawings are intended to explain the invention in more detail.

1 shows schematically a form of implementation of the method according to the invention, starting with a wound yarn and relieving the tension immediately after the drawing.

2 schematically shows another embodiment of the method according to the invention with an integrated spinning, drawing and relaxation process.

. 3 shows schematically the production of a fancy mixed yarn with the aid of the method according to the invention.

In Pig. 1 the yarn 10 coming from the bobbin 1 runs up

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the feed rollers 2 "at normal temperature, around which it writes several turns", then to the stretching rollers 4 _? around which it writes several turns, which is also "kept at ordinary temperature", the yarn running between the roller units 2 and 4 a short length of the heated to a temperature of 25O ⁰ C, touches solid stick. 3 the yarn then passes into the supplied through the nozzle 8 compressed air nozzle 5. There is thrown here by the compressed air in the nozzle prolonging pipe 6 occurs At the top still under the action of the compressed air and runs up to the virtual point 9, where the kinetic energy of the yarn is overcome by the interacting forces of the yarn weight and the very low winding tension caused by 7. The peripheral speed of the device 7 must be limited to one Value can be set that is low enough in relation to the speed of the rollers 4 to the relaxation of the yarn 10 and allow it to be wound under hull or near zero tension.

2 the yarn 10 extruded through the spinneret 11 is solidified by the cooling device 12, prepared on the preparation device 13, taken over by the positively driven feed rollers 14, runs over the curved, hot and solid plate 15 and is then transferred to the normal temperature held, also inevitably driven stretching rollers 16 taken over. It then passes through the relaxation device 17 and is collected in the container 19 without any tension.

In Pig. 3 , the filaments emerging from the spinneret 11 are divided into two bundles 21 and 22 in the cooling zone, each of which runs on a preparation device 13. According to the method according to the invention, the bundle 22 is treated as in FIGS. 3? The two bundles 21 and 22 then run together into the entangling nozzle 25 and are wound up in FIG.

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The following examples are intended to illustrate the invention without restricting it.

In these examples, unless otherwise specified, the various yarn characteristics are used under normal conditions, i.

measured at 20 ^° C. and 65% relative humidity.

The degree of crystallinity of the polyamide is measured by the X-ray diffraction method.

The degree of crystallinity of the polyethylene terephthalate is according to the formula

a i? 55 _{x 100}

0.124

calculated in which d is the density of in a gradient tube measured sample compared to the density of a calibration body and -0.124 the difference between the density of a completely crystallized and an entirely amorphous polyester. The draw ratio for a given elongation is thereby obtained by stretching the yarn between delivery rolls and draw rolls in different ratios. It will then the elongation of the different yarns was measured with the help of an Instron device and derived from this the draw ratio is necessary for the given stretch on the yarn.

The total tension is measured using a Rothschild electronic tension meter measured.

The stretch ratio before or after the contact area becomes of the yarn tension in comparison to a Eurve set up separately and without a contact organ on the relationship between Tension and draw ratio derived. The curling is according to the formula

¹ - χ 100

calculated, in which L is the length of the uncrimped yarn and L ^ is the length of the crimped yarn measured under a load of 0.1 mg / den.

The de-curling threshold is derived from the Eurve "Eraft de-curling stretch" derived by measuring the two values at the beginning of the kink of this Eurve.

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Examples 1 to 7

It is made of several yarns of 30 filaments each made of polyalkylene terephthalate assumed that at different spinning speeds and have the following characteristics:

Examples 12 3 4 5 6 7

Spinning speed

in m / min. 1000 1500 2100 3100 3500 4000 4500 Total titre in dtex 670 535 418 317 284 250 Birefringence 0.005 0.008 0.016 0.037 0.049 0.068 0.083 Shrinkage in

Boiling water $> 42 54 64 68 63 40 6 Crystalline 2 2 2 3 3 6 12 Residual stretching 4.0 3.2 2.5 1.9 1.7 1.5 1.4

As can be seen from the characteristics of birefringence, shrinkage in boiling water or crystallinity, these are Examples 3 to 6 according to the invention, while the examples 1, 2 and 7 are given for comparison.

The treatment conditions for these different yarns are as follows:

Examples 3 4th 5 6th Draw ratio in front of the pen 1.02 1.02 1.02 1.02 after the pen 3.00 2.10 1.91 1.72 Yield stress in g: in front of the pen 125 125 135 155 after the pen 215 220 245 265 ! Pen temperature 248 248 248 248 in ⁰ C: Contact length in mm: 11 11 11 11

These four examples result in a crimped yarn. . In Comparative Examples 1, 2 and 7, none of the acceptable As a result of crimp, the yield stresses, temperatures, and contact lengths were between the two values given below

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Tariffed to find out if the ripple is on a particular one Value occurs.

Examples 3, 1 1 2 7th 02 Draw ratio 3 53 in front of the pen 40 - 01 , 01 1, after the pen 140 - 90 35 ■ , 54 1, - 225 Yield stress in g: in ⁰ C: 220 - 150 ■ - 320 in front of the pen 3 - 130 220 - 130 115 - 255 after the pen 210 3 · - 220 250 - 20th Temperature of the pen 255 - 255 220 Contact length in mm: 20th - 20th 3

Despite these significant variations in treatment conditions these examples do not result in the production of yarns with acceptable crimp.

The crimped yarns obtained from Examples 3 to 6 have the following characteristics:

Examples 3 4th 5 6th Strength in g / tex 44 47 50 48 Elongation fo 8.1 10.0 9.6 9.5 Curling $ 47 57.7 52.4 55.2 Number of semi-arches / cm 5.1 5.8 6.5 4.9 De-curling threshold: Elongation % 5.6 5.5 5.6 5.5 Force g / dtex 3.8 3.8 4.0 3.8

The crimping of the yarns is in the nozzle 5 and the tube 6 according to Pig. 1 triggered where in 8 hot and dry air at 175 ⁰ C

is initiated, reducing the temperature inside the nozzle

is about 105 ° C. The yarns have the following characteristics:

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Examples 3 4th 5 6th Strength in g / tex 46 48 54 53 Elongation $ 11.6 12.5 13th 12th Curling ft 45.8 52.2 48.2 46.1 Number of half arches / cm 3.8 6.8 8.0 7.0 Uncurling eyewave: Elongation % 9.7 8.5 8.4 8.5 Force g / dtex 3.9 3.7 4.15 4.3 Example 8

For comparison, the same yarn as in Example 4 is used as a basis, which has a stretching ratio of 2.09 times in a similar device as in Pig. 1, but without the Pin 3, undergoes. The yarn obtained is not crimped.

Example 9. 10 and 11

It is made of two yarns made of polyethylene terephthalate (Examples 9 and 10) and one yarn made of ethylene terephthalate copolymer started with 5 mol-56 dimethylpropanediol (Example 11). the The characteristics of the starting yarn and the treatment conditions are as follows:

Examples 9 10 11

Spinning speed m / min 3500

liter in dtex / number of filaments 66/34

Birefringence 0.054

Shrinkage i.koch. Water $ 62

Crystallinity $ 4

1.7 / $ 25 2.5 / $ 20 1.9 / $ 25

2100 3000 3030/192 313/34 0.025 0.0295 63 78 3 2.5

Treatment conditions;

Draw ratio before the pin after the pin

Yield stress in g: in front of the post after the post

1.02
1.77

1.01 2.96

750 1300

1.01 2.34

70 175

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248 248 250 7th 12th 9 9.5 3.5 VJl

Examples ^ y 10

Temperature of the pen in ⁰ C Contact length in mm Number of half-arcs / cm

Characteristics;

(The yarn of Example 9 shows after the crimp development according to Example 3 to 6 the characteristics given in [])

Example 9 10 11

Strength in g / tex 51 [53] 76 5 '40 Elongation % 14.3 [17] 15th 11 Curling $ 62.2 [64] 25th 5 37 Number of half arches / cm 9.5 [10.4] 3, 3 5 De-curling threshold: Elongation % 7.4 [9.5] 8th, 6.5 Force g / dtex 4.0 [4.1] 5, 3.1 Example 12

For comparison, the same copolymer as in Example 11, which is spun at a speed of 1000 m / min, a titer of 649 dtex / 34 filaments, a birefringence of 0.0061, a boiling water shrinkage of $ 58, a crystallinity of $ 1.5, and a residual draw ratio of 3.4 times, treated under the following conditions:

AWAY

Draw ratio 1.01 times 1.01 times in front of the pen 3.5 times 3.8 times after the pen Stretch ratio in g: 50 80 in front of the pen 140 200 after the pen 230 255 Contact temperature ⁰ C 5 15th Contact length in mm

None of these yarns have acceptable crimp.

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Example 13

In the integrated device according to Pig. 2 is a polyethylene terephthalate having an intrinsic viscosity of 0.67 through a spinneret having 34 orifices of 0.33 mm diameter and 0.66 mm in length and with a throughput of 99.5 g / min is extruded at 285 ⁰ C. The yarn 10 prepared in FIG. 13 describes several turns around the roll 14 at a circumferential speed of 3100 m / min., Runs over a length of 380 mm over the ^{plate 15 heated to 255 °} C., then over the plate 15 at a circumferential speed of 6650 m / Min, rotating rollers 16 and finally through the nozzle 17 fed with cold air, in order to finally be deposited in the container 19 without any tension.

The yarn obtained in this way has the following characteristics:

liter in dtex 150 Strength in g / tex 49 Elongation $ 10.5 Shrinkage in boiling water $> 12th Number of half arches / cm 5 Curling $ 38 De-curling threshold: Force in g / dtex 3.8 Elongation fo 5.5

Examples 14-17

For comparison, a polyhexamethylene adipamide is used at high speed (Example 14), a polycaprolactam (Example 15) and a copolymer with 95 $ hexamethylene adipamide chain links and 5 $ capronamide chain links (Examples 16 and 17).

The yarns have the following characteristics:

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example 14th 15th 16 17th 0.043 Spinning speed m / min 3000 4000 3000 4000 1.2 Titer dtex / number of filaments 115/23 106/34 150/34 140/34 > 15 Birefringence 0.043 0.037 0.041 1.30-
subject Shrinkage i. boiling water # ; -1.1 * 1.0 -0.5 * Crystallinity $> > 20 > 20 > 15 Remaining stretch at 35? £ elongation 1.47-
subject 1.35-
subject 1.45-
subject 1.02-
subject
1,2-Ms
1.6-
subject Treatment conditions: 220-
250 Draw ratio 3-15 in front of the pen
after the pen 1.02-
subject
1.8-
subject 1.02-
subject
1,3-to
1.55-
subject 1.02-
subject
1,4-to
1.7-
subject Contact temperature? G 220-
255 180-
210 220-
250 Contact length in mm 3-20 3-15 3-15

Neither of these yarns is puckered. This clearly shows that the high-speed spun polyamide yarns, which have high crystallinity and very low boiling shrinkage in boiling water (which can even be replaced in the cases marked with *) through which treatment according to the invention did not result in crimped yarns.

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Claims (7)

P_a <_t <_ <e__n_t_a__n_s ^ 2_ £ -B_.2 -. ^ -. E. 1. A process for the production of a polyester yarn based on ethylene terephthalate which is crimpable after relaxation, characterized in that a yarn made of homo- or copolymer based on "ethylene terephthalate with a birefringence between 0.015 and 0.080, a shrinkage in boiling water of 25 "to $ 80 and a crystallinity of not more than $ 6, is subjected to stretching at such a stretching ratio that its stretching can be reduced to less than $ 15 after stretching, this stretching being located at a point where the yarn has a temperature gradient across its cross-section, which is caused by a short run of the yarn over a solid, polished, convexly curved organ on which a 2 to 30 ⁰ C below the melting point of the polymer '. Temperature is maintained, is effected. 2. The method according to claim 1, characterized in that the yarn subjected to drawing has a birefringence between 0.030 and 0.070. 3. The method according to any one of claims 1 or 2, characterized in that that the yarn subjected to drawing has a shrinkage in boiling water between $ 40 and $ 80. 4. The method according to any one of claims 1 to 3, characterized in that that the yarn subjected to drawing has a crystallinity below $ 3. 5. The method according to any one of claims 1 to 4, characterized in that that the yarn subjected to drawing is a polyethylene terephthalate homopolymer is· 6. The method according to any one of claims 1 to 4, characterized in that that the yarn subjected to drawing is a copolymer which consists of a large proportion of ethylene terephthalate units and consists of a small proportion of units consisting of a diol other than ethylene glycol IO98AO / 082 and / or an aromatic diacid other than terephthalic acid. 7. Crimped yarns according to any one of claims 1 "to 6 can be obtained. 609840/08