DE1660643A1 - Process for the continuous production of stretched polyamide threads - Google Patents

Description

7 / c 12496/66 1-5 / Ko

Toy ο Hay on Kabushiki Kais ha Tokyo (Japan)

Process for the continuous production of drawn polyamide threads

The invention relates to a method for the direct and continuous production of stretched Polyamide threads In particular, the invention relates to ' a process for the continuous production of drawn polyamide threads, in which one melt-spun, fresh Polyamide threads directly from a multi-stage stretching treatment, without going through a winding or winding process or the like.

With the tecaniBchen used so far The manufacturing process for polyamide threads was polyamide

m '. lzf ^. £ J ^r ; cnner., the resulting threads around a bobbin fg ^ wLoko] t and after the stabilization of the wound i} 'hö.an 7 / urderi it is stretched during unwinding from the bobbin. There, but -;, - !. The customary working methods require intermediate stages that require work steps for the cut threads, is the manufacturing process for lasers

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-z-

and threads in two stages, namely, one? Spinning stage and a drawing stage, subdivided, whereby special mechanical devices or plants and operations are required ".

On the other hand, it might be assumed that, wie'sie the spun yarns as such can be obtained proceed according to the melt spinning, continuously to a stretching treatment is subjected \ however, since such fresh threads are physically unstable, a continuous stretching operation can not be expected, in particular since the unstretched filaments become sticky on a heated drawing pin or hot plate and the number of breaks in the drawing stage is large. Accordingly, such a procedure was considered wholly inexpedient: ₀

Recently, there has been a method of making improved, structurally uniform, drawn polyamide filaments vorgescalagen, in which this a multi-stage stretching process in the form of freshly spun threads or after winding up polyamide threads (cf. z. B. British patent specification 989 144) “This method is with respect to the birefringence of the unstretched polyamide threads to '; the stretch ratio is considerable, but it is still unsatisfactory insofar as a fresh thread wider range of stretching conditions than can be used on wound yarn. That means "if under

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such conditions, a fresh, spun polyamide yarn 'immediately Streckbehandlunqen is subjected, besides, numerous cutting or breaking points are produced, which in fact, considerable difficulties' represent _can-β

Thorough investigations have been carried out and it has been found that when a freshly spun yarn is directly exposed to a drawing treatment, there is a zone which is completely different from the drawing conditions of wound and discharged yarns, which is also completely different from the drawing conditions of the known ones described above The method is different, wherein within this zone a stretching or cutting of yarn ^{does not take place during the stretching stage e K} , and accordingly a smooth stretching process can be carried out.

The object of the invention is therefore to create a process for continuous technical production of stretched polyamide yarns baw. - threads, being ^ fresh Polyamide threads spun from the melt in a multi-stage Stretching mg without going through an intermediate wrap or Winding process while avoiding the difficulties, such as yarn or tube breaks, subjected during the drawing stage In particular, appropriate stretching conditions should be provided for this method =.

BAD ORIGINAL 209833/0837

The method according to the invention for continuous Manufacture of stretched polyamide threads, with fresh ones Melt-spun folyamide threads continuously in a multi-stage Subjecting stretching is characterized in that the unstretched threads are subjected to a sireck dimension within the range of 1.25 to 2.90 times pre-drawn, whereby the "double of the melt-spun, stretched threads is 0.001 or less »

In general, fresh melt extruded or expelled polyamide filaments passed through a Spinneret were extruded, unstable in their physical properties compared to the remaining undrawn threads, the crystallinity and orientation of the fresh Threads is very low, while the stickiness of the same is great «If one looks at these unstretched threads leaves a per at ur at Bäum's, takes orientation and Crystallinity with the duration of the standing and the Stickiness decreases »but if between the

the unstretched threads / spinning process and the stretching process / lie for a considerable period of time, this leads to a loss of the advantages associated with a direct stretching process "in which the spun threads as such are subjected to the stretching treatments"

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According to the invention, they are made from a spinneret ejected polyamide threads, which are caused by the action of cold air or the like «are solidified, immediately one Subject to pre-stretching, whereby the Boppe der Laden is not more than 0.001. The stretching can take Use of a known stretching device comprising a pair of first rollers and a pair of second "rollers with a greater peripheral speed "than that ..the first rolling is equipped to be carried out ,, The essential features of the method according to the invention are based on the pre-stretching of freshly spun polyamide thread with a birefringence of at most 0.001 with a stretching amount within the range of 1.25 to 2.90-faced "When using a stretching ratio or to an extent outside the range indicated above, as in the examples below shown wi.-u, numerous yarn breaks during the drawing stage up and the stretching process becomes difficult. As used herein, the term "stretch ratio or amount of stretch" denotes the ratio of the length of age stretches threads to unstretched threads J? Äden j and the expression "total! Stretching ratio or total stretch "represents the ratio of the length the finally stretched threads to the unstretched threads dar »i / io iiei ', drawing" birefringence "denotes the

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Difference value of the refractive index in the direction of the fiber axis and the refractive index in a direction perpendicular thereto. For the effortless and easy implementation of the pre-stretching operation a draw ratio in the range of -1.30 to 2.80 is preferred.

According to a preferred embodiment of the method According to the invention, the freshly spun threads are preheated to 40 to 140 ° G before the pre-drawing. This preheating can be done effortlessly by doing the unstretched Threads threads through hot rollers "

The invention is explained below with reference to the specification explained in more detail »

The curves shown in FIG. 1 show the relationship from load to elongation of unstretched polyamide fibers or threads «,

In Fig., = 2 is the ratio of the stretching temperature in the second stage (a second stage drawing temperature) and the strength of stretched polyamide threads.

In Fig. 3 is a graph showing the relationship the stretching temperature in the second stage to the number of pimples (number of naps) of stretched polyamide strands (multif ilaments) <Ä ° -

In Fig. 4, the the stretching temperature in the second stage to the shrinkage

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in boiling water of stretched polyamide thread material shown".

Curve A in FIG. 1 shows the case in which the temperature of the undrawn polyamide threads is low and insolation takes place during the drawing process. The threads are uniformly stretched up to point P. Then, however, a constriction occurs in one part, the stress on P. being reduced to P ₂ and an unstretched and an elongated part being present next to one another and the constriction essentially below constant maintenance of the B-j requirement is transmitted or forwarded, and after the disappearance of the undrawn part a uniform stretching is carried out the transfer or transfer of the constriction is less smooth and no good stretching can be expected.

The undrawn polyamide threads are preferred

heated to a temperature of at least 40 ° G ^ to the at a subsequently carried out stretching in a second stage of the threads best tendency to break

due to the remaining of an unstretched and a "stretched Part in the threads at a stretching ratio within the range of 1.25 to 2.90 in the pre-stretching

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stage, and in order to reduce this constriction to a minimum as possible * If, on the other hand, the preheating of the undrawn threads is carried out at a temperature of at least 140 ° C, no crystalline orientation is brought about due to the stretching or GgI ₀ in the second stretching stage. This can make the stretching process difficult to finish smoothly.

The pre-drawn polyamide threads are eventually Finished stretched in at least one stretching stage »Die subjected to the stretching treatment described above Polyamide threads can easily be stretched in a second stretching stage.

According to the invention it was found that the second Stretching treatment is advantageously and preferably carried out under the following conditions in order to achieve the physical -Properties of the final stretched polyamide threads or yarns and to facilitate the drawing process in the second stage »

The threads subjected to the stretching are compared. with the = undrawn threads, stabilized, but the pre-drawn threads are not sufficiently thermally stable can be referred to as «To the breaking of the threads in tier

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zvä-th Str ckstufe to "prevent, and the physical _-igensch & ften to improve the final product, the threads before stretching DAEM in the second stage are preferably 4p

ο forward /
up to 140 C / heated »Preheating can easily be done from 3 *. J3, which guides the pre-stretched polyamide threads through hot rollers.

As in -öig. > shown, numerous failures occur when the preheating temperature in the / second stage is below 40 oiler above 140 ° C. Performed as shown in the ^x 'ig _o 2 and 4, is to improve the thermal stability and the strength of the final product in the preheating of the second 3bufe preferably at a temperature of relatively aöheren values of the above-specified range

In particular, the stretching is in the second stage preferably designed so that the final stretching area 4.00 to ά, ΟΟ is to reflect the physical properties of the finished product to improve. This stretching treatment can be carried out using a hot stretching machine, where desired, the stretching in a multiple of Stretch air can be done,

The method according to the invention is in the production of stretched threads from various polyamides _s · z. B, i / ol.yriex-Jim-. Luylenadipamid (iTylon-66) and Po lye apr ο amid (lIylon-6), brewable.

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In this way it is possible according to the invention directly stretched polyamide threads from freshly spun Polyamide thread in technically and economically advantageous . ■ '/ else without' the problem of z. B. Fadenbr Wichen, · to produce, with no passing through an intermediate processing stage, such as winding or winding, is required produced stretched polyamide threads in superlative Way such strength and heat resistance that those of the nacri produced using the customary process . Threads are at least equivalent »

The invention is illustrated below with the aid of examples closer he purifies ο

example 1

■ This example and the -Example nachstoende about 2 illustrate the influence exerted rbeitsgänge of the pre-stretch ratio of the pre-stretching _a.

Polycapronsaur ^ aiuid having an average Iu οlekulargewicht of 18C00 was ner e Spinnteaiperatur of 260 ° G and a spin amount or a Bpinngesoiiwiitdigeit of 400 m / min melt spun. When the birefringence of the coagulated threads reached a value of 0.0008, the threads were heated to about 90 ° G by means of hot rollers and after about 2.7 seconds.

BATH ORIGINAL

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stretched after spinning The stretching was carried out in such a way that a pre-stretching (stretching in the first stage) and a * stretching in the second stage, as shown in Table I below, were carried out so that a GesamtetreckverhäTbnis can be of 4.0, obtained at a drawing speed of 1600 m / min "the frequency of yarn breaks was determined the results are summarized in table I below ₀

Table I. Breakage frequency Total distance Pre-stretch 10 kK each relationship relationship (1st stretch pit) difficult to stretch 4.00 1.10 β η η 4.00 1.20 11 4.00 1.25 10 4.00 1.30 8th 4.00 1.40 5 4.00 1.50 4th 4.00 1.60 0 4.00 2.00 1 4.00 2.4o 1 4.00 2.50 2 4.00 2.60 . 3 ' 4.00 2.70 2 4.00 2.80 4th 4.00 2.90 18th 4.00 5.00 difficult to stredkai 4.00 3.10

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From the above Table I it can be seen that with regard to the frequency of yarn breaks during drawing, good results at a pre-draw ratio of 1.25 to 2.90, in particular from 1.30 to 2.90, are obtained,

• with a pre-stretching ratio below 1.2 or above 3.1, the stretching process becomes discontinuous or unstable o

This example was when stretching in the first Stage, neither a stretching pin nor a heating plate is used, while in the second stage when stretching a straightening pin and a hot plate (with a temperature of about 200 ° C) were used.

Example 2

Polycapramide having an average molecular weight of about 20,000 was measured at a spinning temperature of 28o ° C ™ and a spinning speed of 400 m / min melt spun _o about 15 seconds after spinning, when the birefringence of the coagulated filaments reached the value of 0.0009, were the Yarns stretched, the pre-stretching extent (first stretching stage) and the stretching extent in the second stage being varied so that a total stretching extent of 4.80 was obtained at a stretching speed of 1920 m / min. The frequency of breaks during stretching was determined. The results are summarized in Table II 21 below.

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(first streek level) Breakage frequency Table II 1.20 .1e 10 ks Total draw-pre-draw ratio 1.30 11 ratio ι, βο 5 • 4.80 2.00 4th 4.80 2.40 0 4.80 2.80 2 4.80 3.20 3 4.80 12th 4.80 4.80

From Table II above it can be seen that with a stretching amount in the first stage of 1.3 to 2.8 an advantageous stretching could be carried out »The stretching treatment in this example was carried out in the first stretch stage a heating plate (with a temperature of about 110 ° C) and in the second stage a stretching pin and a hot plate (with a temperature of 210 ° G) is used »

Example 3

Granular polycaproic acid amide with a medium Molecular weight of about 20,000 was found at a spinning temperature of 275 ° C and a splitting speed of 4θΟ m / min melt spun. The resulting fresh threads with a birefringence of 0.0003 were heated to about 90 ° G. Approximately Five seconds after spinning, the filaments were at a pre-draw amount (first streek level) of 2.8 and a total

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stretching amount of 5jO at a stretching speed of 2000 m / min stretched. There was hardly any breakage of the threads during the stretching, and threads became with one Strength of 8.2 g / den. No stretching pin was used in the first stretching stage, but the Threads preheated to 100 ° C, and in the second stretching stage, a stretching pin and a heating plate (with a temperature of about 200 ° C) used «

Example 4

Granular polycaproic acid amide with an average molecular weight of about 18,000 was melt-spun at a spinning temperature of 280 ° C. and a take-up speed of 400 m / min. After the resulting filaments were coafculated, the undrawn filaments, which had a birefringence of 0.0008, were heated to about 65 ° C. by means of hot rollers, whereupon the filaments were immediately drawn. The stretching was carried out, the pre-stretching amount (first stretching stage) and the stretching amount in the second stretching stage being varied in the manner shown in Table III so that a total stretching ratio of 4.0 was obtained at a stretching speed of 1600 m / min . The ends of the weft spool obtained (pirn) were determined. "" The results are summarized in Table III below. .

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Total distance Table III
Torstreek- Number of nubs in
spool / 1000 m a shoe relationship relationship
Cl. Stretching stage) when heated
before d. Torstrasse without heating
before do Torstr. 4.0 1.1 difficult to
stretch difficult to
stretch 4.0 1.2 21 52 4.0. 1.5 2 11 4.0 1.4 0.5 8th *,O 1.5 0 5 4.0 1.6 0 7th 4.0 2.0 0 6th 4.0 2.4 0 9 4.0 2.5 0 10 4.0 2.6 0 5 4.0 2.7 0 7th 4.0 2.8 0.5 11 4.0 2.9 1 13th 4.0 2.0 13th 45 4.0 3.1 difficult to
stretch difficult to
stretch

The number of knobs in the weft spool was low when Wusle heated up in front of the goal stretching. In this example neither a stretching pin nor a heating plate is used during the stretching in the gate stretching stage, while in the second Stage stretching is carried out using a stretching pin and a hot plate (at a temperature of about 210 ° C) wasο

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Example 5

Granular polycaproic acid amide with an average molecular weight of about 24000 was at a spinning temperature of 300 ° G and a winding speed of jj60 m / min melt-spun o The resulting undrawn threads with a birefringence of 0.0009 were raised to about 80 ° C by means of hot rollers heated or not heated and immediately stretched. The pre-draw ratio became fixed at 2.90 and the second draw ratio in the second stage is varied so that a total draw amount of 4.80 to 5.0 was obtained with the stretching at a stretching speed from 1730 to 1800 m / min. the The number of knobs in the weft spool obtained was measured, and the results are summarized in "Table IV" below.

Table IV

Total stretching pre-stretching nubs / 1000 m ratio ratio with preheating without preheating.

(1. Streok level)

4.8 2.9 0 9

4.9 2.9 0 14 5.0 2.9 0.1 18

The results show that significantly lower nub counts were obtained when preheating was performed.

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In this example neither a Stretching pin still uses a heating plate when preheating, while a stretching pin and a heating plate (with a temperature of about 28o ° G) is used in the final stretching stage * th.

Example 6

Granular polycaproic acid amide with an average molecular weight of about 18000 was at a spinning temperature of 28o ° C and a winding speed of 400 m / min melt spun. After the resulting filaments were coagulated, the undrawn filaments became birefringent preheated from 0.0007 at temperatures in the range from room temperature to 150 ° C by means of hot rollers, whereupon the Threads were immediately stretched. It became a total draw ratio of 4.0 and a pre-scatter ratio of 2.5 applied, where tee & w is the stretching at a stretching speed by ΙβΟΟ. ro / min was carried out. The number of knobs measurements were made in the weft spool obtained; the results are compiled in Table V below »

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Table V Number of knobs in the foot
spool / 1000 m Preheating temperature 2.4 Room temp. 0.9. 40 0.2 50 0 60 0 70 ^ 0.1 80 0 90 0 100 1 110 1 120 2 130 3 I4o impossible to stretch 150

These results show that at a preheat temperature good results can be obtained at temperatures between 40 and 140 ° C. Stretching according to this example was performed during preheating neither a stretching pin nor a yeast plate used, with a stretching pin and a heating plate in the final stretching stage (with a temperature of about 205 ° C) were used.

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Example 7

Granular polycäpronic acid amide with an average molecular weight of about 25,000 was melt-spun at a spinning temperature of 300 ° C. and a take-up speed of 400 m / min. The resulting undrawn threads were heated to 40 ° C, 80 ° C and 140 ° C (in the first stage) by means of hot rollers and immediately pre-stretched at a stretching amount of 2.5 (first stretching stage) Rollers preheated to different temperatures (second stage) and by a stretching pin and a heating plate (with a _e ο of 2.0 /

Temperature of about 210 C) at a stretched amount / stretched, to get the finished stretched threads. The strength the number of nubs and the shrinkage in boiling water of these threads were determined. The results are in the figures

T »

2 to 4 graphed the shrinkage in boiling Water is represented by the expression below.

Length of the yarn obtained 4 hours after taking it out of the boiling water, in the length of the origin = which it was for 30

lent yarn «» minutes was immersed _{Y lnn}

Length of the original yarn

From FIGS. 2 to 4 it can be seen that, according to the method according to the invention, a polyamide yarn of high strength is obtained with low number of breaks during stretching and low shrinkage in boiling water

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of the yarn obtained in this way is relatively small

If the temperature of the hot rolls in the first stage and that of the hot rolls in the second stage is less than 40 ° C or more than 140 ^G C, the number of breaks during stretching increases remarkably and the stretching becomes Difficult Even when the draft ratio was brought below 1.25 or above 2.90 under these conditions, the number of breaks also increased considerably, making stretching difficult.

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Claims (5)

. - 21 - ■■ Claims 1. Process for the continuous production of drawn polyamide threads, with fresh, melt-spun Polyamide threads are continuously subjected to multi-stage stretching, characterized in that the undrawn Threads pre-drawn with a stretching amount within the range from 1.25 to 2.90, the sohmelz « spun, undrawn threads have a birefringence of at most 0.001. 2. The method according to claim 1, characterized in that that the undrawn threads were pre-stretched at a stretching amount in the range from 1.0 to 2.8o 3. The method according to claim 1 or 2, characterized in that that stretching polyamide threads made of polyoaproic acid amide. 4. The method according to any one of claims 1 to _9, characterized in that the undrawn threads are heated to 40 to 140 ° C before the pre-stretching » 5. The method according to the eleventh of claims 1 to 4, characterized characterized in that the threads are checked after pre-stretching. further stretching to a total stretching amount of 4.00 to 6.00. 6 _e method of any one of claims 1 to 5, dfltdurch in that the pre-heated pre-stretched filaments prior to further stretching to 40 to I4o ° G. 209833/0837