DE2325139A1 - Process for the production of fully aromatic polyamide fibers - Google Patents

Description

Dr. F. Zumsteln Sr. - Dr. E-. Assman; i Dr. R. Koentgsfoerger "- DlpK-Phys.-R. Hofzbauer - Dr. F. ZumsfeSn jun.

PATENT LAWYERS

TELEPHONE: COLLECTIVE NO. 22S341

TELEX 529979 *

TELEGRAMS: ZUMPAT CHECK ACCOUNT: MUNICH 91139

BANK ACCOUNT: BANK H. HOUSES

8 MUNICH 2.

BRÄUHAUSSTRASSE 4/1 «

Case F1O54-K296 (Teijin) / HSH

TEIJIN LIMITED, Osaka / Japan

Process for the production of fully aromatic polyamide fibers

The invention relates to a process for the production of fully aromatic polyamide fibers on an industrial scale. The invention relates in particular to a process for producing high quality wholly aromatic polyamide fibers of excellent quality Yields that consist in the fact that a spinning solution containing a fully aromatic polyamide dissolved in an amide solvent contains extruded into an aqueous precipitation bath containing calcium chloride, whereupon the amide solvent is advantageously recovered «,

It is known (e.g. from published Japanese patent application No. ₀ 1555/72) that a fully aromatic polyamide, in particular an N-substituted fully aromatic polyamide, can be dissolved in an amide solvent such as N-methyl-2-pyrrolidone to form a spinning solution, which is extruded into an aqueous precipitation bath containing calcium chloride, whereby voliaromatic polyamide fibers are obtained =

Since, however, the solution of a fully aromatic polyamide in an amide solvent, compared with other polymer solutions (e.g. of polyacrylonitrile in N ₅ N -dimethylformamide) ', only ^i:. n ^r ier ^r

d U §i © * $ © f «» «3" ö ■

can be badly precipitated, the fibers can only with an extremely low productivity when they are produced on an industrial scale by the wet spinning process want to manufacture,

If you manufacture fibers on an industrial scale, that is Recovery of the solvent is essential, but no method is known to date by which one Amide solvents in an advantageous manner from precipitating liquids can recover from the precipitation bath »·.

It is therefore an object of the invention to provide a wet spinning process with which it is possible to produce fully aromatic polyamide fibers of good quality with high productivity? place.

Another object of the invention is to provide a method by which one can advantageously use the amide solvent can be recovered from the precipitation liquid that has been withdrawn from the precipitation bath »

The following facts have now been ascertained in the course of the investigations carried out to achieve the above-mentioned objectives:

a) The concentration of the amide solvent in the precipitation bath has a great effect on the course of spinning and the quality of the filaments obtained. In particular, the spinning conditions and the quality of the threads change to a considerable extent when the concentration of the amide solvent comes over a certain limit in a range in which the spinning solution just out of the spinning solution has been extruded and the precipitation of the filaments takes place.

b) The effect of the concentration of N-methyl-2-pyrrolidone on the spinning conditions and the yarn quality in the area of the precipitation bath where the spun yarn emerges, is relatively small and no difficulties arise

309848/1 1 36

a, even if the concentration of the N-methyl-2-pyrrolidqn-s is increased »

c) By extracting the precipitating liquid removed from the precipitation bath with methylene chloride, it is possible to effectively recover the amide solvent _o

d) Since the efficiency of the recovery to a large extent of the concentration of the amide solvent in the withdrawn Depending on the precipitation liquid and the specific gravity of the liquid, these conditions should be special to be strictly controlled »

Based on these findings, the feasible in industrial scale process of the invention has now corresponds · wound, produced according to the wholly aromatic polyamide fibers excellent quality with good spinning conditions and can be recovered the amide solvent in an effective and economical manner _o

According to the invention there is now a method for producing fully aromatic polyamide fibers by extruding a spinning solution a fully aromatic polyamide in an amide solvent in a precipitation bath containing inorganic salts ready-

made, which is characterized in that an aqueous calcium chloride-containing precipitate], liquid which is an amide solvent has a concentration of not more than 3% by weight, in the vicinity of a spinneret, the precipitating liquid in the bath at an average speed not more than 0.1 times the speed of yarn take-up flowing in the yarn conveying direction, the precipitating liquid having an amide solvent concentration of not less than 4% by weight is removed from the bath, the precipitating liquid with an organic solvent consisting essentially of methylene chloride consists, treated and the amide solvent extracted from the precipitation liquid and wins »

30 9.8 48/1 1 3

According to the invention, the average speed of the Precipitation bath expressed as l / 100 (m / min. ') Of the amount of precipitation liquid, which flowed through the precipitation bath per minute per mean cross-section (cm) of the precipitation bath. The mean cross-section of the precipitation bath is the quotient that is obtained by dividing the volume (cm) of the precipitation bath by its height (cm).

The term "wholly aromatic polyamide" given herein stands for a synthetic linear polyamide which is at least 85 mole percent, preferably at least 90 mole percent, of repeating Units of the following formulas I and / or II

-NR ₁ -Ar-NR ₂ CO-Ar'-CO- I

-NR ₃ -Ar-CO- - II '

is built in which

Ar and Ar ', which may be the same or different, bifunctional aromatic rings and

R ₁ , R 1 and R 1, which can be identical or different, hydrogen atoms or methyl groups

mean. ■

Examples of such fully aromatic polyamides are poly (m-phenylene isophthalamide) and copolymers which essentially consist of this polymer (e.g. m-phenylene isophthalamide / terephthalamide copolymer). Those copolymers which contain at least 75 mol% of m-phenylene isophthalamide units are preferred included »Examples of corronomers are m-phenylene terephthalamide, m-benzamide, m-phenylene isophthalate / isophthalamide and itt ^ -Toluyleni soph thai amid.

Suitable solvents for the fully aromatic polyamides are amide compounds such as N-methyl-2-pyrrolidone, N, N- dimethylacetamide, N, N - dimethylformamide and hexamethylphosphoramide, as well Mixtures of these solvents,

309848 / 1T36

The concentration of the wholly aromatic polyamide in the spinning solution is not critical, but is usually 15 to 30% by weight, preferably 18 to 25% by weight _o If desired, the solution may be a pigment such as titanium dioxide or carbon black, 'a dye, a heat ( Contains oxidation stabilizer or a light stabilizer = In addition, inorganic salts can be contained to increase the solubility in the solvent »

If necessary, the spinning solution is filtered off and defoamed and measured and then introduced into the spinneret from which it is extruded into the precipitation bath.

The spinneret has, suitably, at least 5000 openings o Although a donut shape spinneret, through which the precipitating liquid can flow through the middle part, is preferred, a spinneret with a disk-like design can also be used » '

The coagulation bath may be, as illustrated in the accompanying Figures _o 2 of the drawing, be arranged vertically, wherein the spinning nozzle is arranged substantially horizontally and flows through the Eällflüssigkeit from bottom to top ■, or the coagulation bath, in a tapered vessel as shown in Fig _o 3 of the drawing, be included, whereby.die spinneret is inclined and the precipitating liquid flows obliquely upwards from below »

In any case, according to the invention, an aqueous calcium chloride is used containing solution with an amide solvent concentration of not more than 3% by weight on one side of the bath (Rear side and / or spinneret side) in this way into the precipitation bath introduced that it flowed in the yarn conveying direction. Then, on the other side (on the yarn take-out side) of the Precipitation bath removed the precipitation liquid, its solvent concentration has increased as a result of yarn precipitation »

0i§4B / i13

In this way, the area of the spinning nozzle is always supplied a Fällfliissigkeit low solvent concentration, which thread can be produced with good quality at good spinning conditions _o

If the solvent concentration of the precipitating liquid is 3% by weight exceeds, the spinning conditions deteriorate considerably.

The amount of calcium chloride contained in the precipitating liquid is at least 35% by weight, in particular 40 to 45% by weight. Part of the calcium chloride, preferably not more than 35% by weight of this material, can be replaced by at least one inorganic salt, v / ie magnesium chloride, calcium nitrate or zinc chloride. In this case, the concentration of calcium chloride in the precipitation bath is adjusted to not less than 20% by weight, the total concentration of the salts being brought to at least 35% by weight, preferably 40 to 45% by weight. It is at least 60 C, in particular 80 to 100 C. Accordingly, the precipitation liquid to be introduced into the precipitation bath is preferred:
heats.

the b-is at least 60 C, in particular 80 to 100 C. Dem-

LT: preferably to a temperature of about 80 to 100 ° C in advance.

The mean flow rate of the precipitating liquid in the precipitating bath is no more than 0.1 times the yarn take-up speed. the yarn take 5 times used) extremely low "It's surprising that you can achieve stable spinning at a flow rate within this range _o

When the flow rate of the precipitating liquid is 0.1 times exceeds the yarn take-up speed, the amount of per unit of weight into the. Amide solvent entering the precipitating liquid which reduces the concentration of the amide solution

• 308 841/113 6. -,:

2513

This leads to an increase in the amount of liquid to be extracted and recovered, which has an economic disadvantage. Furthermore, the flow of the precipitating liquid in the vicinity of the spinneret becomes turbulent, which causes the threads to stick together so that good quality fibers cannot be obtained, _etc.

The lower limit of the flow rate of the precipitating liquid depends on the fact that during the entire spinning process fresh precipitating liquid with a solvent concentration of not more than 3% must be present »in a precipitation bath Above specified vertical execution can with a flow rate of the precipitation liquid of at least 0.04 times the yarn take-up speed can be achieved that fresh precipitating liquid is always in the vicinity of the spinneret is present o.

The precipitating liquid removed from the precipitation bath is then used Recovery of the amide solvent extracted with methylene chloride «, It is necessary that in this case the concentration of the amide solvent in that taken from the precipitation bath Precipitating liquid at least 4% by weight, preferably at least 5 GeWo-%, is. When the concentration of the amide solvent is less than 4% by weight, the amount of the to be treated in the extraction and recovery stage Liquid so that the solvent cannot be advantageously recovered.

Preferably, the precipitating liquid is removed when a specific gravity of at least 1.36, measured at 60 ⁰ C, "having By this measure, the methylene chloride layer and the layer can easily Fällflüssigkei't of one another up due to the difference in specific gravity (the for methylene chloride at 60 ° C is 1.33), and the extraction can be carried out continuously using a countercurrent extraction process »If, however

309848/1 1 3β

the specific weight of the removed precipitation liquid is less than 1.36, the amide solvent can thereby be extracted and obtained by removing the precipitating liquid

. Reaching mixed with the extractant and the mixture leaves standing.

Advantageously, in the extraction process according to the invention Methylene chloride in an amount of 0.8 to 2.0 times, preferably 1.0 to. 1.5 times the weight of the removed Precipitation liquid used. When the extraction efficiency is at least 60%, preferably at least 75%, is set, the above-mentioned conditions can be met if the precipitating liquid after the extraction returns to the precipitation bath and a stable process of extraction and recovery.

The precipitation liquid from which part or all of the Amide solvent has been removed by extraction with methylene chloride either as such or after concentration has been adjusted to amide solvent or calcium chloride, returned to the precipitation bath.

The amide solvent is recovered from the methylene chloride by evaporation and distillation and reused for manufacture the spinning solution used.

That used in the extraction process of the invention Methylene chloride can also contain other organic solvents with a specific gravity of no more than 1.3 that are found in methylene chloride and i-m amide solvents should be soluble and insoluble in water, such as 1,2-dichloroethane, toluene, Xylene or benzene, but the amount of methylene chloride is at least 85%.

On the other hand, the spinning solution that has been extruded is drawn off upwards with solidification in the precipitation bath and then subjected to a washing process. ^:

0 9 8 4 8/1136

The thread take-up speed from the precipitation bath is preferably set to 1 to 5 m / minute. If the take-up speed is within the range given above, the precipitation can take place more uniformly and you can get break-free threads, which do not have any unevenness caused by the precipitation, with a high Maintain Productivity *

If the distance (H) between the, spinneret surface and of the upper surface of the precipitating bath lies in the area expressed by the following equation, can be a very achieve a stable spinning process. ■

15 © % H έ (2D- + Si - 1.5 S ^:

"where ^λ

D is the titer (denier) of a single thread after drawing and the heat treatment, ranging from 1 to 30 deniers lies, and

S is the speed (m / min ») _s with which the threads are withdrawn from the precipitation bath and which is in the range from 1 to S m / million _e ,

mean. ·

If the distance H is less than the lower limit given above, the threads can lose their transparency in certain cases lose. Furthermore, the individual threads can adhere to one another, and fiber breakage or the formation of fibrous fibers can occur Threads take place »If the distance H is greater than 150 cm it becomes difficult to get the threads at the beginning of the spinning process deduct.

The filaments, which have been added after precipitation are washed with water, to the entrained from the precipitation bath of calcium chloride and the remaining in the threads solvent to remove = Thereafter, the filaments having a certain draw ratio (preferably 2- to 4-fold) in one

. 309848/1136

Warm water bath and / or a steam bath stretched and at least 280 ° C with the exclusion of a shrinkage process at constant Length or stretching (preferably in 5 to 100% stretched ■ -.- ,. State) heat-treated, resulting in highly oriented and crystalline, fully aromatic polyamide fibers.

With reference to the preferred shown in the accompanying drawings Embodiments of the invention are explained in more detail below, for example. "_...-.

Fig. 1 shows the sequence according to an embodiment of the. Invention according to the method as a flow diagram.

Fig. 2 shows a precipitation bath of the vertical version, in which the precipitation liquid flows from bottom to top while.

Fiq "3 shows the view of a precipitation bath in an inclined design, in which the precipitation liquid flows obliquely from bottom to top.

In Figs. 1 to 3, the reference numerals 1 stand for the spinneret, 2 for the precipitation bath, 3 for the threads, 4 for the take-up roller, 5 for the precipitation liquid inlet, 6 for a channel for Receiving the overflowing precipitation liquid, 7 for a precipitation liquid withdrawal opening, 8 and 13 for reservoirs, 9 for a cooling coil, 1O, 12 and 14 for pumps, 11 for an extraction column and 15 for a water wash bath »

One by dissolving a fully aromatic polyamide in one The spinning solution obtained from the amide solvent is extruded through the spinneret into the precipitation bath. The precipitated threads 3 are with a certain take-up speed picked up by the take-up roller, washed in the water bath 15 with water and then fed to the subsequent stretching stage.

On the other hand, via the precipitation liquid inlet 5, which is behind the spinneret is arranged, introduced the precipitating liquid and flows in the direction of that indicated in FIGS

309848/1138

Arrows through the precipitation bath 2o The precipitation liquid flows on the Yarn take-up side from the precipitation bath and is taken up via the channel and then passed through the opening 7 into the reservoir 8. There the precipitating liquid is collected with the help of the cooling coil 9, through which water flows, cooled to about 50 ° C. and then introduced into the upper area of the extraction column 11 with the aid of the pump 10 via the lower area of the extraction column methylene chloride is introduced and in this way the amide solvent is displaced within the column with the aid the methylene chloride extracted from the precipitating liquid. the Precipitation liquid becomes, after the extraction with the help of the pump withdrawn from the lower region of the extraction column and transferred into the reservoir 13, from which the precipitating liquid with the help the pump 14 is transferred again into the precipitation bath o

On the other hand, the methylene chloride containing the amide solvent is taken out from the top of the extraction column and transferred to an evaporator in which the methylene chloride evaporates and separated from the amide solvent is »The amide solvent is then used to. further purification and recovery distilled under reduced pressure. This amide solvent is then used again for the preparation of the spinning solution, while the methylene- Chloride again served as an extractant

According to the inventive method, wholly aromatic polyamide fibers can be made under very good spinning conditions, wherein the training along adhesive or abnormal 'threads is reduced _o Further, the solvent can be recovered in an economic and efficient manner. Therefore, according to the invention, it becomes possible to produce yarns of different denier, which extends from low to high denier, and also yarns with high denier for technical purposes. _r

The following examples are intended to further illustrate the invention, but without limiting it, “The various stated Properties were determined according to the following methods;

. '■ 309848/1138

1) Evaluation of the fluctuation in toughness

This fluctuation in toughness stands for the extent of the Scatter of the measured values of the tenacity of a single thread and is determined according to the following equation:

Tough-strength scatter (S ") of the single-thread tenacity

speed = = 100%

Average value fluctuation (χ) of the single thread count strength

The tenacity of the single threads was determined on 20 samples.

2) Amount of abnormal threads

50 g crude staple fibers were spread by hand and _r were foreign matters such as spin foam, screened unstretched filaments or yarns agglomerated and weighed, and the amount obtained is indicated as% by weight.

3) fiber crimp

A single fiber sample was attached with the help of an adhesive a sheet (distance 25 mm, 3-shape) attached. Then the sample was checked with a torsion or chain crimp gauge and an initial load of 2 mg / denier was applied to the thread, with the number of arcs of the sample was read per mm. The number obtained was based on 25 mm.

4) degree of curl

The sample used to determine the fiber crimp was loaded with 50 mg / denier for 30 seconds, around the crimped To stretch fiber, whereupon the length b (mm) of the sample was determined under the load. The degree of curl was then below Using the following equation determines:

Crimp Degree (%) =. 100

where a is the length of the sample at the initial loading of 2 mg / denier and

30 9843/1138

b the length of the sample at the 50 mg / denier load mean o

5). Degree of curl elasticity and residual degree of curl

After reading the length under the heavier load at the. The total load was determined to determine the degree of curl removed and the sample allowed to stand for 2 minutes. Then the sample was again made at 2mg / denier (the same Load like the original) loaded, whereupon the length c (mm) of the sample was determined "The 'properties were then calculated using the following equations: -. . . ■

Degree of crimp elasticity = ¹⁰ °

Degree of residual curl = - -_ «100

Example 1 ■ '

20.5 parts of fully aromatic polyamide with an intrinsic viscosity of 1.9, which is obtained by copolymerizing m-phenylenediamine, Isophthaloyl chloride and terephthaloyl chloride (mixed polymer molar ratio 98: 2) was obtained, were dissolved in 79.5 parts of N-methyl-2-pyrrolidone, whereupon the Solution to produce a spinning solution was defoamed, which was kept at 70 ° C. The solution was then treated with a Speed of 234 ccm / minute through a spinneret with 6000 holes with one. Diameter of 0.12 mm, which is essentially horizontally, as shown in FIG. 2, was arranged in the lower region of a precipitation bath, into the precipitation bath extrudedo The material was in the precipitation bath in the form of Threads precipitated and then pulled off at a speed of 2.1 m / minute »

The precipitation bath contained a precipitation liquid kept at 95 ° C, which consisted of an aqueous solution containing 1.7% N-methyl-2-

pyrrolidone and 42 % calcium chloride. The precipitating liquid flowing at an average rate of 0.17 m / minute through the precipitation bath (yarn take multiplied by 0 ₅ 08) ₀ On the upper part of the precipitation bath, the precipitation liquid was with a N-methyl-2-pyrrolidone concentration of 6.2% and a specific gravity of 1.375 to 1.380 subtracted at 60 ° C.

The threads that were pulled from the precipitating liquid ", were washed well with water to remove the solvent. ' distant, and then "2.75 — times the original length in boiling water kept at 95 C, then dried and stretched 1.4 times on a hot plate, the was kept at a temperature of 310 C »The threads were then using an upsetting crimper (stuffer crimper), whereupon the crimped tape is cut to a fiber length of 76 mm to form staple fibers became.

The spinning and drawing conditions were good and it went ahead no sticking together, no clouding or breaking of the threads. The number of wrapping errors during the spinning process and the properties of the obtained fibers were as the following: ■

Number of rewind faults 0 to 0.01 per hour

9.97 denier

Toughness. 4.95 g / denier

Strain . 45%

Evaluation of toughness

fluctuation 9.1%

—4 -Amount of abnormal fibers 1 10% by weight

The precipitation liquid removed from the precipitation bath was, as in FIG Fig. 1, transferred to the reservoir and after adjustment placed in an extraction column at a temperature of 50 C, in which they are treated with methylene chloride in an amount equal to that

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51

1.3 times the volume of the precipitating liquid, treated in order to extract the M-methyl-2-pyrrolidone contained in the existing precipitating liquid and to recover it " In this treatment, an aqueous calcium chloride solution with a concentration of N-methyl-2-pyrrolidone of 1.7% continuously withdrawn from the extraction column and returned to the precipitation bath »

Comparative example 1

Example 1 was repeated, with the difference that the amount of precipitating liquid fed in was reduced and the speed of the precipitating liquid were adjusted to 0.03 times the yarn take-up speed, the concentration of N-methyl-2-pyrrolidone in the precipitation liquid to be fed to the precipitation bath gradually decreased, with the spinnability of the Spinning solution deteriorated, at the same time the concentration decreased the precipitating liquid to N-methyl-2-pyrrolidone,. and the specific gravity of the precipitating liquid sank to .below 1.35 g / cc. Eventually it became impossible to use N-methyl-2- " extract pyrrolidone with methylene chloride in the countercurrent extraction column »

Comparative example 2

Example 1 was repeated, with the difference that the supplied The amount of precipitating liquid increased and the average The flow rate of the precipitating liquid was set to 0.15 times the yarn take-up rate «The The concentration of N-methyl-2-pyrrolidone in the aqueous calcium chloride solution which was introduced into the precipitation bath reached 1%, while the corresponding concentration of the withdrawn liquid was 3.5%

The liquid flow in the vicinity of the extracted fibers was very turbulent, and the filaments obtained contained many fine threads, which meant that the Aufwickelstörungen of the spinning process increases "Furthermore, the volume of su in the extraction ε tage liquid to be treated, which

ι o i i 41/111 β ■■■■ "

resulted in an inefficient conduct of the proceedings;

The threads obtained had the following properties: _t

Titer 9.9 denier,

Tenacity 4.4 g / denier

Strain . 41%

Evaluation of the toughness fluctuation 21%

—4 amount of abnormal fibers 650 χ 10% by weight

Example 1 was repeated, with the difference that an extraction liquid with a low extraction efficiency was used. The N-methyl-2-pyrrolidone concentration of the aqueous calcium chloride solution to be introduced into the precipitation bath was 41 %, while the N-methyl-2-pyrrolidone concentration of the precipitation liquid withdrawn from the precipitation bath was 8.5%. A state of equilibrium was established at a specific weight of 1.36. The spinning operation could be carried out, but the thread breakage and disruption of the thread often occurred at the spinning stage, so that it was not possible to carry out the spinning operation in a stable manner

Number of awkwardness disorders 5 per hour

Titer 9 ^ 9 denier

Toughness 4.71 g / sterile

Elongation 42 ^ 1 %

Amount of non-normal fibers 340 χ lo ~ Öweight%

el. -2

2Öj5 Teufe ^ oiy ^ Cm ^ pheHylenisOphthalamid) with an internal viscosity of '1.90 would in 79.5 parts of N-Meth ^l yl-2-pyrröiidöri. dissolved j whereupon the solution would defoam ^ around a spihnlo- ^ surig which was kept at 70 ° C. As shown in FIG. 2, the spinning solution was fed into an annular spinneret at a rate of 316 cc / minute

(donut type spinneret), which had 34,000 holes with a diameter of 0.07 mm and which were arranged essentially horizontally in the lower region of the precipitation bath, was introduced and extruded into a precipitation liquid containing 43% by weight of calcium chloride _o The threads were precipitated and pulled off at a speed of 2.5 m / minute

The precipitating liquid was introduced into the precipitating bath in the same way as described in Example 1 near the spinneret in such a way that the precipitating liquid flowed upwards at an average speed of 0.20 m / minute. Then the precipitating liquid was in the upper Part of the precipitating liquid drawn off was introduced into a countercurrent extraction column and treated with methylene chloride to extract the solvent. The precipitating liquid was then heated to 95.degree. Adjusting the N-methyl-2-pyrrolidone concentration at different values has been sent into the precipitation bath _s returned after which the spinning is continued again "

The precipitated threads were then washed with water as described in Example 1 and drawn 2.73 times the original length in a warm water bath kept at 95 ° C, dried and then on one at 340 ° C held hot plate stretched by a factor of 1.43. After crimping, the threads were cut to a fiber length of 38 mm to form staple fibers. In this case ¹ resulted in the following relationships between the N-methyl-2-pyrrolidone concentration lüssigkei.t the Fällf and the quality of the obtained yarn. ■ ·

30 9848/113

O CD CD

NMP ⁺⁾ -Con- NMP Concentration Specifi Extraction Tough Deh Amount of By- , centering tration of sches · Ge procedure stig tion abnormal leading the supplied withdrawn weight of speed (%) len company ten liquid liquid withdrawn (g / De sern (%) ' speed ^++; speed (%) (%) liquid nier) 1.7 6.2 1.3 8 1
Completely
extracted 5.07 41 ' 0 0 3.0 7.5 1.37 partially
extracted 5.00 39 1 χ 10 " ⁴ 0.05 5.4 9.9 1.36 partially
extracted 4.93 39 25OxlO ~ ⁴ , 4th

NMP = N-methyl-2-pyrrolidone

Feasibility = number of winding failures on the winding roller

of the first stage, expressed in number / hour.

Example 3

Using the spinning solution prepared in Example 1 and of the spinning bath indicated in Fig. * 2 became the spinning performed under the following conditions

Precipitation bath: ■ Aqueous solution kept at 70 ° C

solution containing 37.5% calcium chloride "

Supplied precipitation liquid NMP concentration 1.5 %. Drained precipitation liquid NMP concentration 5.8 % Specific weight: Ij345 g / ccm

The precipitating liquid withdrawn from the precipitation bath was brought to a temperature of 50 ° C. and transferred to the container. The liquid was then mixed with a solution which had a specific gravity of 1.29 g / ccm at 30 ° C. and of 90 parts of methylene chloride and 10 parts of toluene, mixed for 20 minutes »This mixture would then be left _{to stand}} so that the methylene chloride / Toluo.1 mixture containing N-methyl-2-pyrrolidone could separate out» The remaining precipitating liquid was extracted again in the same way and then incorporated Application of the fine Zivei-Stüfeh process extracted and finally returned to the precipitation bath *

The threads obtained were treated in the same way as in Example 1, with the formation of staple fibers = the draw ratio was 2.73 in boiling water and 1.43 on the hot plate. The transparent threads obtained would have a tenacity of 5.2 g / elongation and an elongation veh 38 $ 5 % »

Example 4

2Öj5 parts of a fully aromatic polyarriide with a viscosity of 1.8%, which had been obtained by copolymerization of m ^ Phertylendiairiih with isophthälöyicftiörid ühd Terephthälöyicftiörid ıhd Terephth'aiöylfchi & rid ■ (MischpoiymerisätiörisvethMithis whereupon O ₅ 2 parts of alcohol were added.

The spinning solution was applied in an amount of 355 ccm / minute an annular spinneret (donut type spinneret) with 34,000 holes with a diameter of 0.07 mm, which were arranged almost horizontally in the lower area of the felling bath, extruded into a precipitation bath of the vertical embodiment. The extrudate was precipitated in the form of threads in the precipitation bath and then recorded at a speed of 3.1 m / minute. In the lower area of the felling bath was in the same Way, as described in Example 1, an aqueous Cal- cium chloride solution with a calcium chloride concentration of 42%, which was kept at 73 ° C, so close to the Spinneret introduced that the precipitation liquid with an average Speed of 0.19 m / minute flowed upwards. Eventually the precipitating liquid was from the upper one Area of the felling bath removed. The withdrawn precipitation liquid was via a container in the upper area of a countercurrent extraction column introduced. In the lower part of the extraction column, methylene chloride was 1.5 times Amount of the precipitating liquid introduced, whereupon the extraction was carried out in a countercurrent process with stirring.

The precipitation liquid removed from the lower area of the extraction column was returned to the lower area of the precipitation bath, in which the spinning process was continued.

The N-methyl-2-pyrrolidone concentration of the aqueous calcium chloride solution which was introduced into the lower region of the precipitation bath was 1.5 0.2%, while the N-methyl-2-pyrrolidone concentration was that withdrawn from the precipitation bath precipitating liquid, which at 60 ° C has a specific gravity of 1.38 ± 0.01 g / cc having, 6.7 - 0.5%.

The recorded. Threads were washed well with water to remove the solvent, then 2.2 times the original Length stretched in boiling water at 95.degree. C., dried, then 1.9 times more than a hot one 310 C held plate stretched, heat-treated, in a Upsetting curling machine curled and under training 'of

309848/113 6

Staple fibers cut to a fiber length of 51 mm "

The spinning operation was carried out under good conditions, and there were no disturbances _s like a tearing of the yarn "Pie filaments obtained had the following properties on

Titer ■, ' I ₅ , 78 denier Toughness'. 5.03 g / denier Strain - 43.8% Evaluation of the fluctuation in tensile strength 8.6% Thread puckering 5, l / cm Cl3 / inch) Degree of curl (visible) 18 % Residual curl degree 12.5 % Example 5

22 parts of the polymer used in Example 4 were dissolved in 78 parts of N-methyl-2-pyrrolidone _s whereupon the Lösung.entschäumt was so. a spinning solution was obtained which was kept at 70 ° C »; . ,

The spinning solution was at a temperature of 70 ° C. form in an amount of 353 cc / minute into a coagulation bath of the inclined execution, as sie.in FIG _o is 3, extruded, wherein; a Spinndüse'verwendet was, which was based on the horizontal plane and inclined at 4O aufwiese 6000 mm holes with a diameter of 0.12, The precipitated filaments were withdrawn at a rate of 2 $ 1 m / minute. "

In the lower portion of the precipitation bath a calcium chloride solution with a Caleiumchloridr concentration of 42% and a temperature of 95 ° C was introduced in such a _t in the vicinity of the spinneret that the Fällflüssigkoit achievable in the coagulation bath an average rate of 0.07 m / minute te _o The precipitation liquid was then drawn off from the upper area of the precipitation bath near the yarn take-up point _o

The precipitating liquid removed was introduced into a reservoir "' and then under the same conditions as in Example-4

wrote, with methylene chloride in a countercurrent extraction column subjected to an extraction treatment and then 'for the another spinning process fed to the precipitation bath again.

The aqueous calcium chloride solution introduced into the lower area of the precipitation bath had an N ~ methyl-2-pyrrolidone concentration of 1.7 £ 0.2, while the precipitation liquid removed from the precipitation bath, which at 60 ° C. had a specific weight of 1 , 3 possessed 7 to 1.38 g / cc, had an N-methyl-2-pyrrolidone concentration of 6.5 ί 0.2 % . The threads obtained were drawn and crimped in the same manner as described in Example 1, staple fibers having a titer of 15.5 denier, a tenacity of 4.8 g / denier and an elongation of 45.0%.

Example 6 "

18 parts of poly (m-phenylene isophthalamide) having an inherent viscosity of 2.2 were in 82 parts of N-methyl-2-pyrroÜdon. ge— solves. The spinning solution obtained, which was kept at 70 C, was placed in a precipitation bath of the "inclined" at a rate of 16 ccm / minute Execution method as it was applied in Example 5, extruded, with a spinning inclined by 50 to the horizontal -: nozzle with 720 holes with a diameter of O, OS mm was used deducted from 10 m / minute «

Near the spinneret was in the lower: area; the precipitation bath containing an aqueous solution having a temperature of 95 ⁰ C ,, the 25% calcium chloride and 18% Zinfcchlorid introduced such that the precipitation liquid reached minute in the coagulation bath an average flow velocity of 0.2 m / s. A precipitating liquid was then taken from the yarn draw-off opening in the upper area of the precipitating bath. "

The precipitating liquid withdrawn in this way "was via a Reservoir led and then under the same conditions as described in Example 4, extracted with methylene chloride and

then again recirculated into the precipitation bath within the lower 'introduced the range of the precipitation bath inorganic salt solution had an N-methyl-2-pyrrolidone concentration of 2 ί O ₉ 5%', while the drawn off from the precipitation bath inorganic salt solution at 60 ° C, a specific gravity of 1, -38 to I ₅ 39 g / ccm possessed a N-methyl-2-pyrrolidone concentration of 7 ± 1 - had%.

The threads obtained were washed well with water, -um that 3.2 times the original length when kept warm at 95 C. Water stretched, dried, up 1.43 times a plate heated to 330 ° C and stretched at one speed The obtained Yarns showed the following properties:

Titer 1650 denier

Number of threads 720.

Tenacity 7.5 g / denier

Strain . 21%

Young's initial modulus 121 g / denier

Example 7 ,

The spinning solution used in Example 4 was in an amount of 241 ccm / minute in a precipitation bath of the type shown in Fig _o ^, which had different distances from the spinneret surface to the surface of the precipitation bath, via a ring spinneret (donut type spinneret) with 34 000 holes with a diameter of 0.07 mm extruded. The precipitated threads were taken up at a speed of 2.1 m / minute, washed with water, dried and crimped and cut under the same conditions as in Example 4 to form staple fibers.

From the following table it can be seen that threads of good quality could be obtained at heights of 50 cm and 85 cm, while at a height of 20 cm the threads broke and stuck together and the number of abnormal fibers increased, It was therefore difficult to produce good quality staple fibers.

. . . 308848 / 1-13 $ ■ -

Distance from the Tough strain lot valuation Spinneret top stig <%) the un the tough area up to speed 42.0 normal strength s- Surface of the (g / den.) ¹ 43.8 Fibers fluctuation Felling bath (cm) 5.11 37 (%) C%) 85 5.03 0 8.4 50 4.25 0 8.6 20th 76X) xlO ~ ⁴ . 21

In each case, the precipitating liquid introduced into the precipitation bath existed from a 42% aqueous calcium chloride solution, which has an N-methyl-2-pyrrolidone concentration of 1.7 ί Ο, 2% exhibited. The precipitating liquid withdrawn had an N-methyl-2-pyrrolidone concentration of 6.5 ± 0.5% and at 60 ° C a specific gravity of 1.3 8 ± 0.01.

The withdrawn precipitation liquid was in the same way as described in Example 4, treated with methylene chloride and then returned again to das.Fällbad.

Example 8

20.5 parts of a fully aromatic polyamide with an intrinsic viscosity of 1.9, which is obtained from m-phenylenediamine, 'isophthaloyl chloride and terephthaloyl chloride (interpolymerization ratio 97: 3) were obtained in 79.5 parts of N-methyl-2-pyrrolidone solved, whereupon the solution was defoamed. At a temperature of 70 ° C., the was obtained in this way Spinning solution through a spinneret with 34,000 holes with a diameter of 0.07 mm into an aqueous solution kept at 73.degree 41 weight percent calcium chloride solution extruded. A precipitation bath of the type shown in FIG. 2 was used as the precipitation bath is used, the distance from the spinneret surface to the surface of the precipitation bath being 100 cm. Spinning was done using different extruded ones Polymer quantities and yarn take-up speeds.

309648/1136

The mean speed of the aqueous calcium chloride solution in the precipitation bath was adjusted to 0.08 times the yarn take-up speed. The N-methyl-2-pyrrolidone concentration of the aqueous calcium chloride solution was brought to 1.5-0.2%, while the N-methyl-2-pyrrolidone withdrawn from the coagulation bath Konzentratidn the precipitating liquid 6.5 ± 0.5%, respectively (specific gravity at 60 ^° C to 1,365 l, 37.g / cc). The precipitating liquid withdrawn was treated with methylene chloride in the same way as described in Example 4 and returned to the precipitation bath. ■

The precipitated threads were washed with water, stretched, crimped and in the same way, as described in Example 4, processed into staple fibers. Here, the following relationship became between the yarn take-up speed and the quality of the yarn determined. At a yarn take-up speed of 7 m / minute, there was a considerable deterioration in the Transparency one, and it could only be fibers with unsatisfactory Quality are preserved.

Thread take-up
accepted
Schwin-
age
(m / min.) Titer
(Denier) Tough
sturdiness.
(g / denier) strain
(%). Appearance. 2.1-
3.5
6th 1.92
1.95
2.01. 5.4
5.2
.3.5 41
43
31 transparent
transparent
not transparent

Example 9 "..

A fully aromatic polyamide with an intrinsic viscosity of 1.7, which consists of 47 parts of m-phenylenediamine, 87 parts of isophthaloyl chloride and 3 parts of terephthaloyl chloride was, was dissolved in dirnethylacetamide at room temperature, where- ' in one a spinning solution with a polymer concentration of 22% received. The spinning solution kept at room temperature was at a rate of 3 80 cc / minute through an annular one

309848/1

Spinneret (donut-shaped spinneret) with 34,000 holes with a diameter of 0.07 mm, which are in the lower area of the felling bath was arranged, extruded into the precipitation bath of the vertical type, whereupon the precipitated filaments at a speed of 3.0 m / minute were withdrawn.

A precipitating liquid with a specific gravity of 1.366 g / cc with, contained 60 ⁰ C, the dimethylacetamide in a concentration of 1.0% and calcium chloride in a concentration of 39%, was fed at a temperature of 60 ° C from the back of the spinnerette introduced into the precipitation bath in such a way that the precipitation liquid flowed through the precipitation bath at an average flow rate of 0.24 m / minute (yarn take-up speed χ 0.08). The liquid with a dimethylacetamide concentration of 4.5 % and a specific weight of 1.350 g / ccm at 60 ° C. was drawn off at the top of the precipitation bath.

The threads removed from the precipitation bath were washed with water, to remove the solvent to 2.73 times the original length in hot water, stretched at 95 ° C, dried with the help of a hot roller and again on one hot, held at 320 ° C plate stretched 1.45 times.

The spinning and. Horizontal bar conditions were good, and those received Threads exhibited a titer of -2.0 denier, tenacity of 5.28 g / denier and an elongation of 39.5%.

The precipitating liquid withdrawn from the precipitation bath was poured into a Transferred container in which the temperature is lowered to 50 ° C became. The precipitating liquid was then transferred to a container in which it was filled with 1.3 times the volume of methylene chloride Was mixed for 20 minutes with stirring. Then the mixture was allowed to stand for 2 hours and the material was extracted in two Steps to get the precipitating liquid from the dimethylacetamide containing Separate the methylene chloride layer. The methylene chloride layer was evaporated and distilled to give the methylene chloride to be separated from the dimethylacetamide. The precipitating liquid recovered in this way was returned to the

30 9 348/1136

bad convicted.

Example IO ",

Example 9 was repeated, with the difference that a coagulating liquid having a specific gravity 'of 1.384 g / cc at 6O ⁰ C, a calcium chloride concentration of 25% and a zinc chloride concentration was used by 14%. The threads obtained had a titer of 2 _? 0 denier, tenacity - of 5.42 g / denier and an elongation of 38 _? 4%.

The precipitating liquid removed from the precipitation bath had a dimethylacetamide concentration of 4.5 % and a specific weight of 1.386 g / ccm. The precipitating liquid was transferred to a container in which the temperature was lowered to 50.degree. The material was then transferred to an extraction column and treated continuously with 1.3 times the volume of methylene chloride in order to recover the dimethylacetamide from the precipitation bath. ■

During this treatment, an aqueous solution of calcium chloride was used and zinc chloride with a dimethylacetamide concentration of 1.0% is continuously drawn off and returned to the precipitation bath.

t example 11

A fully aromatic polyamide with an intrinsic viscosity of 1.9, which was obtained from 47 parts of m-phenylenediamine _s 87 parts of isophthaloyl chloride and 3 parts of terephthaloyl chloride, was obtained in N-methyl-2 with formation of a spinning solution with a polymer concentration of 20.5% -pyrrolidon dissolved * The solution was defoamed and at a temperature of 70 C in an amount of 316 ccrn / minute through an annular spinneret (donut-shaped spinneret) with 34,000 holes with a diameter of 0.07 mm, which in the lower area of the precipitation bath, extruded into a precipitation bath o The extrudate obtained in the form of threads was taken up at a speed of 2.50 m / minute «,

309348/1138

The distance between the surface of the spinneret and the surface of the precipitation bath was 85 cm. From the rear of the spinneret, an aqueous inorganic salt solution of the type indicated in the following table was obtained: Composition with an N-methyl ~ 2-pyrrolid: on concentration . of 1.7 t 0.2% and a specific weight of. 1.398 g / cc introduced into the precipitation bath at 60 ° C. ■

The precipitating liquid flowed at an average speed of. 0.20 m / minute C yarn take-up speed multiplied by the. Factor 0.08) through the precipitation bath, and a precipitation liquid was drawn off at the yarn take-up side of the precipitation bath, which had an N-methyl-2-pyrrolidone concentration of 6.5 ±, O _S 5 % and a specific weight of 1.3 72 at 60 ° C =,

■ "temperature of the

Composition of the precipitation liquid Fällflussigkei.fc

1) 35% calcium chloride and

8 % magnesium chloride

2) 25% calcium chloride and 18 % magnesium chloride

3) 35% calcium chloride and 18% calcium nitrate

4) 25% calcium chloride and 18% calcium nitrate

5) 25% calcium chloride and 15% zinc chloride

6) 25% calcium chloride, 10% zinc chloride and 5%. Calcium nitrate

The resulting undrawn strand was washed until the residual amount of solvent in the fiber reached 8 % , whereupon the fibers were drawn 2.2 times their original length in hot water at 97.degree Roll dried and heat-treated on a hot plate heated to 340 ° C., the strand being stretched by 90%. The strand was then oiled, crimped and cut into staple fibers.

95 ° C. 95 ° C. 95 ° C. 60 ° C. 60 ° C ' 75 ° C.

309848/1136

On the other hand, the drawn off from the precipitation bath precipitating liquid was collected in a container in which the temperature was adjusted to 50 ⁰ C. The precipitating liquid was then transferred to an extraction column, in which it was extracted with 1.5 times the volume of methylene chloride to separate from E- methyl-2-pyrrolidone. The extracted precipitation liquid was from the lower area

D-he extraction column withdrawn and fed back to the spinning process ¹ =

The fibers obtained according to this procedure showed the following properties: -

Composition,
the precipitating liquid
speed denier Tough
sturdiness
(g / den ») strain
(%) Evaluation of the
Toughness
fluctuation (%) 1) 2 ₅ O3 5.29 ~ 36 _? O . 8.3 2) 2.05 4.9.7 34.1 7.6 3) 2.03 5.33 33.0 6 _S 5 4) 2.04 5.07 30.2 12.6 5) 2.00 5.18 32.4 10.8 6) 2.02 5.54 34.0 8.6
I.

Example 12

A fully aromatic polyamide with an intrinsic viscosity of 1.95, which had been obtained by copolymerization of 45 mol% of m-phenylenediamine, 45 mol% of isophthaloyl chloride and 10 mol% of m-aminobenzoyl chloride, was obtained with the formation of a spinning solution with a polymer concentration of 20% dissolved in N-methyl-2-pyrrolidone. The solution was at a rate of 234 ml / minute through a spinneret with 6000 holes with a diameter of O ₅ 12 mm, which was arranged at one end of the precipitation bath, into a precipitation bath extruded, whereupon the precipitated threads were withdrawn at a speed of 2.1 m / minute "

41/11

One consisting of a 43% aqueous calcium chloride solution Precipitating liquid with an N-methyl-2-pyrrolidone concentration of Ij7% was with a temperature of 95 C from the back The spinneret was introduced into the precipitation bath in such a way that an average flow rate of 0.17 m / minute resulted. A precipitating liquid was introduced via the yarn outlet of the precipitation bath with an N-methyl-2-pyrrolidone concentration of 6.0% and a specific gravity of 1.382 g / ccm at 60 ° C

The filaments were withdrawn from the coagulation bath, were * washed well with water to remove the solvent, then to the 2.76 times the original length in boiling, stretched at 95 C retained water ₅ dried and then redissolved in a hot plate held at 300 C stretched 1.60 times.

The spinning and Verstreck conditions were good, and there were no problems such as sticking, opacifying or tearing of the fibers, "The fibers exhibited a tenacity of 4 ₉ 47 g / denier and an elongation of 30%"

On the other hand, the precipitating liquid withdrawn from the precipitation bath was transferred to a container in which its temperature rose 50 C was brought. Then the precipitation liquid was in.eine Introduced extraction column, in which it was treated with 1.3 times the volume of methylene chloride to the N-methyl-2-pyrrolidone recover from the precipitation liquid. At this Treatment was an aqueous calcium chloride dissolved with-mg an N-methyl-2-pyrrolidone concentration of 1.7% continuously taken from the extraction column and returned to the precipitation bath *

0 9 8 4 8/1136

Claims (9)

Claims lc) A process for producing vollarornatischer polyamide fibers by extruding a spinning solution of a wholly aromatic polyamide in an amide solvent in an aqueous, inorganic salts containing precipitation bath, qekenn terized in that an aqueous. Precipitating liquid containing calcium chloride * which has an amide solvent concentration of not more than 3% by weight, close to one Introduces spinneret so that the spinning liquid in the Bath at a medium speed not more than 0.1 times the yarn take-up speed in the yarn conveying direction the precipitating liquid having an amide solvent concentration of not less than 4% by weight ', subtracts from the precipitation bath, the precipitation liquid with an organic solvent that is in the consists essentially of methylene chloride, treated and the amide solvent is extracted from the precipitating liquid and recovered » 2o) Method according to claim 1, characterized in that the spinneret is essentially horizontal in the lower area of the precipitation bath is arranged, the extruded from the spinneret and precipitated in the. Threads are pulled upwards » 3o) Method according to claim 1, characterized in that the mean speed of the precipitating liquid 0.04 times to 0.1 times the yarn take-up speed amounts to" 4o) Method according to claim 1, characterized in that the spinneret is inclined in the lower area of the precipitation bath and the extruded from the spinneret and Threads precipitated in the precipitation bath are pulled off obliquely upwards. 3QSS4S / 1 13 5.) The method according to claim 2, characterized in that 'the Spinneret has at least 5000 holes and the yarn take-up speed is 1 to 5 m / minute., 6.) Method according to one of claims 1 to 5, characterized in that that the precipitating liquid is withdrawn when it has a specific weight, measured at 6.0 C, of at least 1.36 g / ccitr, and in countercurrent with methylene chloride is extracted. 7 ») Method according to buckets of claims 1 to S ₇ characterized by: that the withdrawn precipitation liquid in countercurrent with a mixed solvent consisting of at least 85%: ffetirylene chloride and another organic solvent with a specific weight of. Is 1.3 g / cc ,, which is insoluble soluble in Methyleachlorid and the Amidickungsmittel and _r is in water, extracted ,,. 8.) The method according to claim 5, characterized in that the Distance H (in cm) between the surface of the spinning iron and the upper surface "of the precipitation bath corresponds to the following relationship: . 150 έ H ^ (2D + ■ 5) ■ .- 1.5 S. wherein S is the speed at which the threads leave the felling bath can be removed, and D is the single thread titer of the threads finally obtained and where 1 ί D ί 30 and 1 i S S 5 « 9.> The method according to any one of claims 1 to 8 _r, characterized in that the amide solvent used is N-methyl-2-pyrrolidone * ■ ΙΟ. ) The method according to any one of claims 1 to 8, _L. characterized in that: the amide solvent used is N ^ N -Bimethylacetamide « ™ " 11ο) method g, according to one of claims .1 to 10, characterized., that the concentration of the wholly aromatic polyamide in the spinning solution is 15 to 30% by weight, 12 ») Method according to one of claims 1 to 11, characterized in that, that the vol! aromatic polyamide: at least 75 mol% units derived from m-phenylene isophthalamide contains » 13ο) Method according to one of claims 1 to 12, characterized in that that the aqueous precipitating liquid containing calcium chloride is an aqueous solution, the calcium chloride at a concentration of 20% by weight and another -Salt, whereby the total salt concentration of the solution is at least 35% and the calcium chloride makes up at least 65% of the total salts » 14ο) Method according to one of claims 1 to 13 _5, characterized in that the aqueous precipitation liquid is an aqueous calcium chloride solution with a concentration of at least 35% » 15 =) Method according to claim 13, characterized in that Magnesium chloride, calcium nitrate and / or zinc chloride are used as additional salts. ο) Method according to one of claims 1 to 14, characterized in that that the temperature of the aqueous precipitating liquid is at least 60 ° C » 3Ό9Β4 8/1136