DE1660360C3 - Process for the production of highly shrinkable and crimpable polyacrylonitrile threads - Google Patents

Description

I 860

males finally in an irocknenen p

at 100 to 260 C around 1.15 to 1.35 times nacliversireect will.

According to a preferred embodiment, the preheating with an aqueous medium at i carried out at a temperature of 60 to H5 C.

Such threads retain their bulk to a much greater extent than known threads, and the normal wet spinning of acrylic threads does not become unduly complicated or expensive.

The mechanical crimping can take place in the usual way, for example in the stuffer box or by gear crimping.

The modification according to the invention of the customary wet spinning of polyacrylic threads thus creates threads which have a considerable shrinkage capacity in a hot, aqueous environment and thereby regain their crimp. When re-stretching the crimp is removed, i.e. a permanent crimp is converted into a latent crimp, so that the fiber can be processed well on textile machines, but the latent crimp is formed again during a later treatment with moist heat. In order to give re-drawn threads better processability on textile machines, they are often given a mechanical crimp after the re-drawing. However Di'.se later crimp is different from the configuration of the crimp according to the invention, since the ^Kr:; .usel of the drawn threads is easily lost on treatment with hot moisture.

In the embodiment in which the threads are preheated and crimped while r, ic v, that is, still in the wet Ciel state, this is done Preheating preferably with oil) up to 85 C. Below No perfect crimping is achieved, and when using increased crimping pressure / ur stronger crimp will easily damage the fibers. Uei temperatures of over K5 C can the threads become soft and under the crimping pressure begin to stick together and change the cross-section. The threads can too begin to shrink when the gel is wet and lose transparency.

The dehydration of the crimped wet gel threads takes place - as already mentioned - in a known manner. If the structure is not collapsed during drainage, then they have strong shrinking filaments, poor gloss and undesirable properties, leading to numerous voids is due in the fiber structure.

In order to stabilize the crimp against the influence of hot water, the dehydrated threads in the relaxed state, which allows for a shrinkage, with steam from about 10 to about 140.degree treated in a known manner. The threads relaxed in this way are then dried under dry conditions Hot stretched conditions.

In order to determine how much must be stretched during the final hot stretching in the process according to the invention. was an acrylic fiber cable between two hot plates of 150 ^; C is re-expanded to different degrees after it has relaxed in steam at 125 C! had been.

table

Raw fiids Degree of curl S. Hot spot (In front of the back (»0) after de ratio
tinter dry under dry conditions) 14.0 conditions number - number the ripple - the ripple 15.5 _ l, 15 times - 15.1 1.24 times - 14.1 1.31 times - - 13.2 l, 35 times - 13.6 ] .39 times - 9.1 l, 48 times - 6.8

Strongly nipping threads
after boiling in hot water
from 100 C

KriuiselungsErad Shrinkage graph Co) (· :.) 13.5 13th 12.8 19th 12.8 25th 12.5 28 8.4 29 6.2 29

From the results of Table 1, it can be seen that the degree of shrinkage of high shrinkage Threads as a result of treatment in hcificm water is too small when the draw ratio is below 1.15, and accordingly a bulky yarn using these threads shows insufficient volume after bulking. If, on the other hand, the draw ratio is over 1.35 decreases the ability of the threads treated in hot water to restore them Curl off as shown above. The stretching speed varies depending on the distance between the hot Plates and the width, the thickness and the stretching speed of a cable to be treated and is in the temperature range from 100 to 260 C.

In the embodiment according to which dehydrated threads are preheated in steam before relaxation and get curled. w, rd preheating is preferred carried out in an aqueous medium between 80 and 95 "C.

Cables made from acrylic threads of a copolymer of 90 ° o acrylonitrile and 10 ⁰ O methyl acrylate, which have been stretched, dehydrated, crimped and treated with saturated steam at 125 ° C. under hot, humid conditions, are stretched to various degrees under hot, dry conditions, and the strongly shrinking threads obtained are treated in hot water at 100.degree. The crimp properties of these threads are summarized in Table 2, from which it can be seen that at a draw ratio below 1.15 the shrinkage

The degree of efficiency in hot water is too low and you puffy. Yarn containing such threads is insufficient in the bulking described above Volume will develop. The table also shows that with a stretch ratio of about 1.35, the tendency of the filaments to regain their crimp after the heat treatment is disadvantageous is influenced so that the bulky yarn has a reduced volume.

Table 2

I. Stretch ratio L'r ^ 'ii -iit->. Hi degree of Strongly shrinking threads warming number Degree of curvature Shrinkage (dry, healthy) Knuiselzam Ripple ("V) in hot water of! 00 ° C the ripple ("O) amount ( ¹ Vo) 16.0 15.4 _ 15.0 12.3 13th i, 15 times - 14.2 12.8 19th l, 24 times - - 13.8 12.2 25th 1.31 times - 13.9 11.3 28 1.35 times - 8.5 7.2 29 l, 39 times - - 5, fi <\ o 29 1.48 times

The stretching temperature varies depending on the Gap between the hot plates, the width uik.) Thickness of the cable to be stretched and other factors, however, is between 100 and 260 ° C.

The acrylic fiber used for the purposes of the invention can be a polymer or a mixed polymer with at least 50 "" acrylonitrile.

The monomer which, in addition to acrylonitrile, is optionally used as a component of the above-mentioned acrylic fiber can be selected from a number of different ethylenically unsaturated monomers, such as vinyl acetate. Vinyl propionate, methyl acrylate. Ethyl acrylate. Vinyl pyridines, acrylic sulfonic acid. Methaci ylsulfonsäut e. Acrylic acid. Methacrylic acid and the like. The proportion of severely shrinking threads according to the invention to be incorporated into a voluminous yarn will vary according to the type and titer of the less shrinking fiber to be mixed with it and the desired feel of the finished voluminous yarn, but can vary from 20 to 70 "". \ orzugswcise of 3 (1 bi \ 60 "rich η. when the percentage is below 20, the bulky yarn will have an unsatisfactory shape, while no bulking is achieved when the percentage is more than 70. the little shrinking fiber , can be made of various natural fibers such as wool and cotton, but low-shrinkage acr \! fibers or other synthetic fibers can also be used (amount of shrinkage in hot water of 100 C under about 5 "<>) ·

The invention and its two embodiments described above are presented in the following Hand of examples explained in more detail. All parts are understood in terms of parts by weight. if nothing else is specified.

example 1

10 parts of a copolymer of acrylonitrile and 90 ⁰ O o lO ° Mcthylacrylat are dissolved in 90 parts of a 48 ° / o aqueous solution of sodium thiocyanate. The spinning solution obtained in this way is pressed into a 1% aqueous solution of sodium thiocyanate at a temperature of 0 ° C. The threads are washed in a wet gel state in water while they are stretched twice their length stretched again, in hot water at a temperature

a5 temperature from 98 to 100 ° C by 5 times its length. The titer of the drawn monofilament is 2.1 den and the total titre of the tow 55,000 den, while the water content is S6 ° / n, based on dry yarn. This cable becomes continuous

drawn through water at a temperature of 80 ° C and introduced into a stuffer box for crimping. The threads are then placed in an atmosphere with a drying flask temperature for 10 minutes of 120 C and a relative humidity of 20 "η drained and collapsed.

The treated cable has a water content of 2.3 ⁰ O. This cable for 10 minutes under saturated steam with a temperature of 120 C

exposed, treated with oil and then dried, resulting in single threads of 3 denier (thread K). The threads K are stretched 1.3 times their length between hot plates at a temperature of 150 ° C., cooled, crimped and then cut to a length of 89 mm. Shrinkable fibers L. This gives greatly To a strongly shrinking fiber according to the conventional method to manufacture to Vergleichszwccken, the treatment was carried out under the same conditions as in the fiber L, but no curling was effected after the Heißvcrstrcckcn under wet conditions, but this was done by Termination of the steam treatment. In this way, a conventional high-shrinkage fiber M was produced. The fibers L and M are mixed with merino wool in a ratio of 50:50. The yarns obtained in this way are treated in a relaxed state for 10 minutes with boiling water, gradually cooled to a temperature of 60 ° C. and dried. The bulky yarn obtained from fiber L was a very bulky yarn, while the yarn obtained from fiber M was less bulky and was very poor in feel and appearance.

The comparative thickness of the two yarns, calculated for the same count, shows a relationship from 87 for the W fiber yarn to 100 for the L fiber yarn.

Example 2

A slightly shrinking thread K, which had not been hot drawn under dry conditions as described in Example 1, was cut into lengths of 89 mm and mixed in a ratio of 50:50 with fibers L obtained according to the invention or conventional fibers M and spun into a voluminous yarn. The yarn thus obtained was dyed with a cationic dye in the docking machine. The temperature at which dyeing was started was 60 ° C, and this temperature was gradually controlled at 100 ⁰ C and held for 40 minutes at this level, "5 which she at 60 ° C was gradually lowered. The yarn was consequently subjected to a bulky mesh treatment at the same time as the dyeing. After washing and treating with finishing oil, the yarn was dried. The bulky yarn obtained by mixing fibers with L fibers was strong and lays very nicely, while the yarn obtained by mixing fibers with M fibers was slightly inferior in strength and was lower in Vo - showed as luminosity, the thickness ratio of the first yarn to the second yarn being 100: 92.

Example 3

10 parts of a copolymer of 90% acrylonitrile and 10% methyl acrylate were dissolved in 90 parts of a 48% strength aqueous solution of sodium thiocyanate. The spinning solution thus prepared was injected into a 10 ⁰ / o aqueous solution of sodium thiocyanate of 0 ° C. The tow was washed with water while it was stretched to 200% of its original length. The cable was then stretched further in hot water from 98 to 100 ^° C. over 500% of its length. After the two stretching processes, the threads had a denier of 2.1 and the tow 55,000 den, the moisture content being 86% (based on dry threads). This cable was dehydrated in hot air with a drying flask temperature of 110 ^° C. and a relative humidity of 20% for 10 minutes. The tow was then passed through hot water at 90 ° C and then fed into a stuffer box where it was puckered. The cable was then treated for 10 minutes in a steam tank with saturated water vapor at 120 ° C. and then oiled and dried. This finally resulted in threads N in front of 3 den.

These threads were drawn 1.31 times between hot plates before 150 ° C. After cooling, the threads were crimped and cut to a length of 98 mm to produce strongly shrinking fibers P. As a control, a strongly shrinking fiber of the conventional type Q was produced under the same conditions as were used for the production of fiber P, but this fiber was not crimped immediately after dehydration, but rather only after the steam treatment.

Yarns were produced in which the above two strongly shrinking fibers P and β were each mixed spun with merino wool in a ratio of 50:50. The yarns obtained in this way were treated with boiling water in the form of a dock for 10 minutes. The yarn was then allowed to cool to 60 ° C. and dried. The bulky yarn containing the fiber P had a pleasing twist and good bulk, while the bulky yarn containing the fiber β was poor in feel and easily lost its bulk.
The relative caliper was 89 for the bulky yarn containing the β fiber to 100 for the bulky yarn containing the P fiber.

Example 4

A little shrinking thread, made in the same way as in Example 3, but without stretching under dry hot conditions, was cut to 89 mm in length. This fiber was with the fiber P according to the invention or conventional fiber β in the ratio 50:50 mixed spun into voluminous yarns. These were in a batch dyeing machine with colored with a cationic dye. The temperature rose gradually, starting from 60 ° C Raised 100 ° C, held at this level for 40 minutes and then gradually decreased to 60 ° C. on in this way the yarns were dyed and made bulky at the same time. The yarns were eventually washed with water, finished with oil and dried. The bulky yarn containing fiber P had a good volume and a good twist, while the yarn containing the ι aserß, was slightly inferior in volume and showed thin spots. The relative thickness of the Docking was 93 for the bulky yarn with fiber β and 10 for the bulky yarn with fiber P.

309 685/261

Claims (2)

and if necessary orientational stretched. This is followed by a complete relaxation and shrinkage in a third warm water bath, 1. Process for the production of high-density, whereupon the threads run through a bath and then shrinkable and crimpable polyacrylic fibers are dried - Rising and shrinking in the third bath can be a result of the gel threads, treatment of the dehydrated drying and relaxation stage. According threads in the relaxed, a shrinkage enable USA. Patent 3 041705 a Fadenlichendem state with steam of about be io cable that has already been thermally relaxed, ME-110, the so corresponds mechanically issued crimps to about 140 ⁰ C and drying. Crimped acrylic-tensioned threads, characterized by mechanical crimping after the net, that the threads are obtained after the thermal relaxation, can indeed stretch and thus before or after the dewatering by stretching with a residual shrinkage as before their relaxation with steam at 15, but the crimps generally disappear completely on reheating in an aqueous medium to 60 to 95 ° C and the threads thus preheated mechanically stretch and do not develop again in the process of being crimped and the dried ones - Subsequent dyeing stage or another hot-tensioned thread finally in a dry water treatment. The bulk of the end product atmosphere at 100 to 260 ° C around 1.15 to 20 tes is therefore low, because in this case they are only stretched 1.35 times . However, the threads do not shrink due to additional 2. The method according to claim 1, thereby causing curling. indicates that the preheating with such a high shrinkage thread is namely aqueous medium at a temperature of 60 borrowed in a mixture with threads of low shrinkage up to 85 C. 25 used to make yarns and fabrics det, which should be bulked in a subsequent heat treatment. This is due to the shrinkage of the strongly shrinking threads ren, whereby the little shrinking threads 30 must form loops or waves. If it is now possible, not during the heat treatment only a bulkiness through shrinkage but rather The invention relates to a method of manufacture, also by forming additional crimps Highly shrinkable and crinkleable targets result in a more durable and thicker construction polyacrylonitrile thread by wet spinning of the Polymc 35 loop. This would also add another disadvantage ren to a cable of Gelfädcn, stretching, remedy such mixed fibers, namely that the watering of the gel threads, treatment of the dehydrated, strongly shrinking threads in such yarns Threads in relaxed, a shrinkage allow- concentrate in the core, while the less In a corresponding state with water vapor from around 110 shrinking threads loosely around the core up to about 140 ° C and drying the so relaxed 40 lie and thus the yarn quickly back on construction threads, schigkcit loses. In the previous production of acrylic threads, the object of the invention is therefore the conversion After the wet spinning process, the wet gel from permanently crimped threads becomes latent threads stretched in the cable, drained and then in the crimped threads, so that later heat-treated relaxed State with water vapor of about 110 45 hung in addition to the shrinkage also a real one Treated until about 140 ° C, and the relaxed thread crimping occurs. dried on the willows. For the production of threads The German patent specification 949 078 describes the high shrinkage after such a process it is known to steam the dried, relaxed threads in the stretched and tense state, to be stretched again at elevated temperature, 50 However, too great a rotatability should be eliminated Fibers to produce, which then merge and one through the latent tension in the thread the effect of an increased temperature is a shrinkable tendency to curl or twist, E.g. in a boiling water bath or dye side. The treatment is intended to result in the bath. In order to reduce such threads to conventional Tcx crimps, which is to be expected, To be able to process tihnascliinen, you will find that a latent ability to creak through heat ruffled. The wet spinning and stretching of mechanically crimped threads and kening and dewatering of the threads is known to be eliminated from re-drawing. U.S. Patents 3,080,210 and 2,984,912. Surprisingly, however, it has been found that The crimping of polyacrylonitrile threads is also over by a suitable combination of process steps known from these references, and from the 60 the latent curling ability after a re-Swiss language Patent 326,912 is known to stretch and retain the original Krausevor the mechanical curling of the fibers can be restored, Zen. Line post-heat treatment after the Krau- The process ordered that the threads in the his of threads is z. B. from the German patent connection to the stretching and before or after document 949 078 known. According to US Pat. No. 65, drainage and, before releasing it, with water-3 080 210 the threads run after spinning steam with an aqueous medium to 60 to 95 ° C through a first and second bath and are preheated and the threads preheated mechanically then at the same time washed with hot water to be crinkled and the dried relaxed