DE1944507A1 - Process for making an elastomeric continuous yarn - Google Patents

Description

19U507

Kanegafuchi Boseki
Kabushiki Kaisha

Tokyo / Japan

Process for making an elastomeric continuous yarn

The invention relates to a method of manufacture an elastomeric continuous yarn with reduced stickiness and improved dynamic properties,

Recently, elastomeric fibers, that is, the so-called "spandex" fibers and the like, have found widespread use. For this reason, there are still many points to be improved in their technical manufacturing process. One of these improvements has been directed to a melt spinning process for making the elastomeric fibers because of its generally high productivity compared to a wet or dry spinning process. This is particularly true with regard to the

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production of continuous yarns.

In the melt-spinning process for the production of elastomers Fibers, however, have encountered the problem that the freshly spun fibers wound on a bobbin stick together and are difficult to unwind from the spool. Furthermore are even in the pail that the wound on a reel Freshly spun filaments are not sticky for a while, but most of them are sticky when they are are wound on the spool in the tensioned state for a long time. This also causes them to stick together. This phenomenon is hereinafter referred to as "sticking" 'are designated.

As such, the stickiness arises from the lower crystallinity the elastomeric fibers. A special quenching process was used to avoid this stickiness suggested for the spun threads, the use of anti-stick agents and the use of taik in the spinning process. However, these measures have not proven entirely satisfactory.

The present invention has various studies and works on the properties and characteristics melt-spun elastomeric fibers.

It is a first object of the invention to reduce the stickiness of the elastomeric filaments in the spinning process. Another- 'terea The aim is to produce elastomeric continuous yarns that have improved dynamic properties and reduced Have stickiness.

The invention therefore provides a method that

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is characterized by the combination of the following successive process steps melt-extruding a segment elastomer from the opening or openings of a spinneret; quenching the extruded elastomer to solidify it, thereby forming a continuous yarn; successive drawing of the continuous yarn formed to stretch it by at least 30 % of its original length; Relaxation of at least 50 io of the stretching of the yarn and winding of the yarn onto a bobbin.

The invention will be explained in more detail below with reference to the accompanying drawings. Show it:

FIG. 1 and FIG. 2 are schematic cross sections of a method for carrying out the method according to the invention suitable device.

Figure 3 is a schematic cross-sectional view showing a method of measuring unwind tension of the yarn from the bobbin.

Figures 4 to 9 are diagrams showing the respective unwind tension of the elastomeric continuous yarns.

In the device according to FIG. 1, the elastomer granulate is introduced into the filling funnel 1 into a screw extruder 3 and heated and melted there. The melt is then dosed by means of a measuring pump 4 and discharged from the openings a spinneret 5 is extruded into threads 6. The threads are in a cooling chimney 8 by cold air flowing from a fan 7 is released, quenched and then run over an oil roller 9 »guide rollers 10 and 11 and

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reach the first take-off roll 12. (The threads are generally obviously firm in the cooling chimney .) The threads 6 are pre-stretched between the first take-off roller 12 and the second take-off roller 13, through an air sucker 15 as it relaxes successively are carried on, and then after passing one

Loose guide 16 wound onto a receiving tube 17. The fan 14 is used to cool the elastomeric yarn, that during stretching between the take-off rollers 12 and 13 Has developed warmth. This fan can be omitted because there is natural heat dissipation.

The air sucker 15 is used to prevent the wrapping of the elastomereη fe yarn around the second take-off roller 13 when the yarn is between the. second take-off roller and the receiving tube 17 is relaxed. The air extractor can be omitted in the case of a suitable relaxation rate or replaced by another device with a similar function. If, for example, suitable holding rollers, consisting of metal rollers, the surface of which has been treated with aventurine, and a pressure rubber roller are used as the second take-off roller 13, then the elastomeric yarn can easily be removed from the rollers so that the air suction device can be dispensed with. In the same way, the first take-off roller 12 can also be replaced by holding rollers.

In general, an elastomeric yarn exhibits increased Adhesiveness to the rollers and also has a low modulus, namely a low tensile strength recovery force when stretched so that the holding rollers can be used to advance the yarn without that any sliding phenomena between the rollers and the yarn are associated with it, instead of the so-called.

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Nelson rollers, i.e. drive rollers with an inclined, idle separation roller as shown in FIG. The guide rollers 10 and 11 can be omitted if not required.

On the other hand, the take-off rollers 12 and 13 can be omitted if the draw is at least $ 30 of the original length of the yarn between the first Guide roller 10 and the second guide roller 11 is made.

FIG. 2 shows a further embodiment of a device suitable for carrying out the method according to the invention. In this device, the take-off rollers 12 and 13 are omitted. 1, the extruded threads 6 come down through a cooling chimney 8, run one after the other over oil rollers 91 and 92, a first guide roller 101, a first separating roller 102, a second guide roller 110, a second separating roller 111, an air suction device 15 and are then wound onto a receiving tube 17 after passing through a sliver guide 16. During this run, the yarn is drawn between the first guide roller 101 and the second guide roller 110 to stretch it by at least 30 i <> of its original length. At least 50 io of the stretching is relaxed between the second guide roller 110 and the take-up tube 17 before the take-up. The air sucker 15 serves to prevent the elastomeric yarn from wrapping around the second guide roller 110. Br can be omitted in the case of a suitable relaxation rate.

By the peripheral speed V) of the feed roller, which feeds the yarn into the drawing zone

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and by the circumferential speed V _{2 of} the take-off roller at which the yarn is removed from this zone, a stretching ratio can be determined, provided that naturally sliding phenomena between these rollers and the yarn can be neglected should be set so well that such sliding phenomena are minimized to a negligible value.)

The draw ratio (in fo) can be given by the following formula;

( ^V 2 - 1) χ 100

⁷ T

In order to release at least 50 % of the applied elongation of the yarn, the take-up speed or the take-up speed should be less than the surface speed of the take-off roller, i.e. the second take-off roller 13, as shown in FIG. 1, at which speed the yarn from the entanglement zone is removed. If, for example, in Fig. 1 the guide rollers 11 and 10 and the first take-off roller all have the same peripheral speed, for example 100 m per minute, and the second take-off roller 13 has a peripheral speed of 200 m per minute, then the stretching ratio is calculated as 100 fo. In order to wind the yarn on a bobbin with relaxation of at least 50 fo dor previously given elongation, the maximum take-up wind V3 of the bobbin 17 should not be greater than 150 m per minute. (If V3 is 200 m per. Minute, then the relaxation ratio is 0 fo and if V _{5 is} 100 m per minute, the relaxation ratio is 100 fo.)

The elastomeric yarn can go through a series one after the other many rollers that transport the yarn, i.e. in several Steps can be stretched or relaxed.

In such eiaom Pail should the difference between the peripheral speeds between the first ZuführungswalzG and the roller, which rotates at the highest rotational speed of all, be calculated stretch ratio of at least 30 i ". With regard to the relaxation ratio, the determination is similar to the above. At least two series of stretch-relaxation can be done in series. The yarn can be stretched and / or relaxed on a conical roller around which the yarn is wrapped and moved many times. Whatever complicated processes the yarn may go through, the draw ratio is always given by the first addition speed V and the maximum feed speed Vmax. The relaxation ratio is determined on the basis of V, V and the final winding

\ j πιει χ

speed V ^ determined as follows:

Aspect ratio (56) = (-ψ ^ ~ Ό x ^ OO

V V

Relaxation ratio (96) = (,, - ^:: - ~ ·) χ 100

As already stated, in order to reduce the sticking phenomenon, a suitable value is the draw ratio at least $ 30, preferably at least # 50 and even better, at least 100 # · In general, the larger is the draw ratio, the lower the appearance the stickiness. A draw ratio that is most effective and suitable is in the range between

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- ο -

100 io and 500 ^σ / ο. As already stated, the relaxation ratio should be at least 50 io, preferably at least 75 i> , a ratio of at least 80 i being most preferred in practice. The relaxation ratio is a factor related to the winding tension. In the case of a small relaxation ratio, ie a high winding tension, an undesirable stickiness phenomenon occurs in the yarn.

Naturally, it is, although usually the expansion ratio is less than 100 io elongation, possible the expansion ratio 100 ^ or to make more, namely to let the yarn shrink shorter than the original length when heating the yarn in the relaxation zone. Likewise, the yarn can be heated in the drawing zone and / or on the feed rollers or the like for the purpose of a thermal fixation that may be required.

The method of the invention can be used with other conventional Methods of preventing the stickiness of elastomeric materials Yarns like the quenching method and the talc method are combined. These conventional methods or devices for this purpose, the method of the invention can either precede or follow it. .

The reasons why after the method of the invention the stickiness of the yarn can be reduced are not yet fully understood, but it is believed that the The following two causes are decisive: First of all, it can be said that the cooling of the yarn can be accelerated. Generally speaking, elongation represents one "Elastomers represent an exothermic change of state, while the

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Contraction is an endothermic change. Therefore, in adiabatic stretching of the elastomer, one occurs Heat release. During adiabatic relaxation after the expansion decreases the temperature due to a self-cooling effect. In addition, heat will be like that Temperature of the elastomeric yarn during the stretching process increases, released and then further accelerates cooling. In the case that an elastomeric yarn, which has developed heat in the stretching step, is cooled to room temperature, then it is believed that in the the yarn on the subsequent relaxation stage a temperature below room temperature cools itself.

Secondly, the solidification of the elastomer could be achieved by pulling, i.e. by orienting the molecular chains be accelerated. Although there is no concrete evidence of this, the elastomer, which has been made crystalline at times by drawing or stretching, part of the crystals or the molecular Maintain orientation, although this can be an extremely small part, even after it comes back has returned to a relaxed state.

The method of the invention has the very important effect that the tackiness of an elastomer is endless Yarn as shown in the following. Examples will be shown is prevented. In addition, it can can be carried out easily and with high performance. In the method according to the present invention, the Stretching and relaxation levels according to the Raine made a spinning stage and are therefore very advantageous in industrial production. Since furthermore the appearance of the stickiness of the elastomeric endless

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19AA507

- ίο -

Most closely observed yarn immediately after spinning the process stages of stretching ; and the relaxation involved in the method of the invention one after the other after the roving stage and before the take-up stage carried out have the greatest effect. · About · shows although that according to the method of the invention obtained elastomeric continuous yarn tends to have a slightly reduced elongation at break, an excellent one Breaking strength and springback after stretching and, in most cases, a pre-reduced Reconsolidation, which is one of the advantages of the inventive Procedure is.

The term "elastomeric endless yarn" used in the description and the claims should be understood to mean a mono- or multi-filament yarn which consists of an elastomer which, for example, has an elongation at break of at least $ 100 (usually about 200 to 1000 fo) , has a springback at $ 100> elongation of at least 80 ° / o (usually at least 90 %) and an initial morinl of at most 1 g / d (usually at most 0.5 g / d). Such an elastomeric endless yarn can be obtained by melt-spinning an elastomer. The so-called fc. "Segment elastomers" are called which are block copolymers of "soft segments" (in most cases with a molecular weight of about 500 to 5000) and "hard segments" with aromatic cores or with strong intermolecular forces. These soft segments are derived from a polyether with a low melting point, such as polyethylene glycol, or a polyester with a low melting point, such as polyethylene adipate and poly-epsilon-oaprolactone.

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19U507

One of the best known segment elastomers, like those above called v / earth, consists of polyurethane.

α polyurethanes useful in the process of the invention include all common polyurethane elastomers. Generally an organic diisocyanate and a polyalkylene ether glycol or a polyester having terminal hydroxyl groups with each other to form a prepolymer implemented. This prepolymer is datin a kottendidening reaction with a "Chaiii-Extondcr", v.'ie one Diamine, diol or polyoil to form a polyurethane Implemented elastomers.

Examples of organic diisocyanates are aromatic, aliphatic and alicyclic diisocyanates, such as toluene-2,4-diisocyanate, toluene-2, 6-di23ocyanate, diphenylmethane-4 , A- diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate and para xylene diisooyanate.

Examples of Polyalkylenäth & r-Glycols are Polyäthylenäther-Glykol, Polypropylene Ether Glycol, Polytetramothylon Ether Glycol and polyhexamethylene ether glycol and their copolymers and mixtures. Glycerin and trimethylolpropane can also be used be used.

The hydroxyl-terminated polyester can be prepared by ring-opening polymerization of a lactone in the presence of a small amount of a glycol or by polycondensation of an excess of a diol with a dicarboxylic acid. Examples of lactone are <\ Va} .erolakton,. ' -Butylolactone and h -caprolactone.

Preferred diolo are polyalkylene glycols, such as ethylene glycol,

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19U507

Propylene Glycol, Tetramethylene Glycol and Hexamethylene Glycol? cyclic glycols such as cyclohexanediol and aromatic Glycols such as xylylene glycol. Examples of suitable acids are succinic acid, adipic acid, Sebacic acid and lerephthalic acid.

Examples of the "chain extenders" are hydrazine and diamine, such as ethylenediamine and methylene-diorthochloro-aniline as well as the glycols described above.

Examples of suitable polymerization catalysts ^ are triethylamine, triethylenediamine, U-ethylmorpholine, Dibutyltin dilaurate and cobalt naphthenate.

Since these polyurethanes are well known per se no further details are given about this. However, as in the method of the invention, the polyurethane segment elastomers are to be subjected to a melt-spinning process to give an elastomeric continuous yarn, the reaction conditions in the production of these polyurethanes should be controlled so that the value for the Melt viscosity of the resulting polymer at Pre-spinning is within a suitable range, which enables melt spinning.

The elastomer obtained according to the process of the invention Endless yarn can naturally be cut into staple fibers will"

The invention is illustrated in the examples. In the examples, the melt viscosity was as follows. determined ι '

The polymer was applied at a preselected temperature .

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- 1 j ~

melted, then heated for another 10 minutes to reach the melting state and then through an opening with a diameter of 0.3 mm and a length of 1 mra spun at a pressure of 50 kg / cm. From the flow velocity the melt viscosity was calculated for the melt.

example 1

Poly-epsilon-caprolactone with an average molecular weight of 2000, which had hydroxyl groups as both end groups, obtained by polymerizing a small amount of ethyl glycol, was reacted with diphenyl methane diisoeyanate. The chain was then extended by adding ethylenediamane as a "chain extender", as a result of which the elastomer E. was obtained. The elastomer E ^, which had a melt viscosity at 210 ⁰ C of 1,020 poises was melt-spun in a device according to FIG. 1. In this device, both the melting zone and the spinneret had a temperature of 210 °. The spinning orifices were 0.25 mm in diameter. The ratio of the rotational speeds of the first guide roller 10 to the second guide roller 11 was 0.99. That of the second guide roller 11 to the first take-off roller 12 was 0.98. The addition speed V _{1 of} the first take-off roller 12 was determined. The addition speed V of the second take-off roller 13 and the take-up speed V ^ were varied according to the information in Table 1. Six types of yarn were produced.

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Table 1

Yarn V ₁ (m / min) Vp (m / min) V ^ (m / min) stretching relaxation

relationship (%) relationship (;

Y ₁ 400 404. 410 1

80 80 80

80

² 400 480 416 20th Y ₃ 400 600 440 50 ^Y 4 400 800 480 100 ^Y 5 400 1200 560 200 y 400 1600 640 300

When calculating the stretching reserve and the relaxation ratio, an elongation of about 3 fo between the guide roller 10 and the first suction roller was neglected due to its insignificance. The extrusion rate of the polymer was adjusted so that the resulting fineness of all endless yarns 80 don. fraud.

The tackiness of the aforementioned yarns Y ₁ to Yg, which was found 24 hours after being spun, was measured by means of a device according to FIG. 3. In the arrangement according to FIG. 3, a yarn sample 18 is guided successively through a guide 19, a tension detector 20 and a guide 21 and taken up by a winder 22. Using a tension meter with a resistance wire as a tension detector, the unwinding tensions were measured at an unwinding speed of 100 tu per minute with a Soiireibor-

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ORIGINAL INSPECTRp

Oscillograph recorded on a measuring sheet. The unwinding tension of the yarns Y ₁ to Y ₆ are shown in FIGS. It can be seen from these figures that the larger the draw ratio, the smaller the unwinding tensions, that is, the tackiness.

Lerner the tackiness of the yarn in the same manner was measured as above, except that the speed Y m is ₁ 400 per minute, the speed V ₂ of 800 meters was per Mioute and that the expansion ratio to 30 fo, 50? o, 70 fo, 80 fo and 88 fo was varied. It was found that the larger the relaxation ratio, the lower the stickiness observed. At a letdown ratio of 30 fo the Klcbrigkeit took in Pig. 5 a. When the speeds V ^ and Y ₂ were fixed at the above values, it was difficult to increase the Int stress ratio beyond 88 fo.

Table 2 shows the tensile strength, the elongation at break, the tension recovery at 100% elongation of the yarns Y- ^ and Ytllt

compiled.

Table 2

Yarn tensile strength- elongation (fo) Stress recovery (g / d) at 100 fo elongation

Y ₁ 0.95 570 94.5

^T 5 1.03 540 97.0

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Then, in the cases where the yarns Y ₁ to "Yg in the original state were wound on their bobbins, certain periods of time indicating the changes in tackiness corresponding to the elapsed time" were determined. The results are compiled in the table.

Table 3

G rn Mitt Elwert the Dev ent ^ voltage (g) _______ 1 St.nach dom ^ day after the 9 days after dom spinning spinning en Verspinn

7.5 7.7 4.8 3.4 3.3 1.8

It has been made clear that the process of Yarns made according to the invention have a smaller increase in stickiness corresponding to the increase in elapsed time, i.e. that they have less tackiness.

¹ 4.5 6.2 ^Y 2 4.4 6.3 ^Y 3 4.0 4.6 ^Y 4 3.1 3.3 ^Y 5 3.0 3.2 ^Y 6 1.5 1.5

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1 9 A A 5 O

Example 2

To the two terminal hydroxyl groups of polytetraniethylene glycol with an average molecular weight of 1500, which has been reacted with diphenylmethane diisocyanate Buthandiol was still given as a "chain extender", creating an elastomer Ep with a melt viscosity was obtained at 225 ° C from 620 poises.

The elastomer Ep was melt-spun in the device according to FIG. The temperature of the Schmolz zone and the spinneret was 225 ⁰ C. The spinning orifices have a diameter of 0.25 mm. The peripheral speed Vj of the first guide roller / was set to be constant while the peripheral speed V _{2 of} the second guide roller 110 and the take-up speed V * * were varied as shown in Table 4: Thus, 13 kinds of yarns were obtained.

Table 4

Yarn V ^ (m / min) V ₂ (m / min) V ^ m / min) Draw-Relaxation ^ - Ratio ($) ratio (<f ₀ )

70 30 50 75 30 50

^Y 7 500 505 510 1 ^Y 8 500 600 530 20th ^Y 9 500 650 605 30th ^Y 10 500 650 575 30th ^Y 11 500 650 537 30th Y ₁₂ 500 750 675 50 ^Y 13 500 750 625 50

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Port setting Table 4

G-arn λ Γ .j (m / min) Vp (m / min) V ^ (m / min) Varstreckun
relationship Voltage
ratio (> fc ^Y 14 ■ 500 750 562 50 75 ^Υ 15 500 1000 350 100 30th 16 500 1000 750 100 50 Y ₁₇ 500 1000 ■ 625 100 75 ^Υ 18 500 1500 700 200 80 500 2000 800 300 80

The extrusion rate of the polymer was adjusted so that that the resulting fineness of the entire endless yarn is 50 den. of 10 threads.

The stickiness of the G-arno Y7 to Y ₁₀ , ._ _1T ,, ",.

^& '19 was 10 minutes on the ·

measured in the same way as in Example 1. The results are shown in Table 5.

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Table 5

", Unwinding tension (g)

Mean value maximum value minimum value

¹ I 4.4 12.1 2.0

^Y 8 4.2 11.0 2.9

^Y 9 4.3 10.8 2.7

^Y 1C 4.1 7.5 ² ^

^Y 11 3.9 7.0 2.2

^Y 12 4.2 11.2 2.7

^Y 13 4.1 6.5 2.6

^Y 14 3 _y ! 3 4.7 2.1

¹ V: -4, "10.5 x 2.4

^Y 1C 3.7 6.3 2.2

^Y 17 3, C 4.3 1.5

^Y 1S 2.3 3.2 1.1

^Y 19 1.2 1.7 0.5

From Table 5 it can be seen that the yarns Y ₁₀ Y ₁₁ , Y ₁ ^, ^Y 14, ^Y 16 » ^Y 17 ^JY 18 ^{and Y} 19, ^{which had been produced according to the} process of the invention, had a lower tack and that in particular the yarns Y ₁₇ , Y _1a and Y _{19 had} extremely low tack values.

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19U507

In Table 6 below, the tensile strength, elongation at break and the Spannungsrückfaderung at 100 io elongation of the yarns Y y, Y] y, Y] _Q and Y ^ g is collected.

Table 6

Yarn tensile strength- elongation (%) Spamiungsrückesspringigkeit (g / d) at 100 # elongation (#)

0.87 360 0.95 320 0.97 320 0.96 310

■ 93.1 97.0 96.8 96.2

It can be seen from Table 6 that the yarns obtainable according to the process of the invention are excellent Properties such as tensile strength and the elastic resilience.

The yarns Y _n , Y

17th

and

off the spool

wound back on a cone. The rewinding from the bobbin to the cone was carried out at an extremely low speed so that the tension of the running yarn did not become too great. In all of the cases where the yarns Υγ, Y ₁₈ and T-jg were allowed to stand on the cone for certain periods of time, the changes in stickiness occurred corresponding to the elapsed time

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measured. The results are shown in Table 7.

Table 7

^Y 7 0.5 Y ₁₇ 0.5 ^Υ 18 0.4 Y ₁ 9 0.4

Yarn middle word of the unwinding tension (g)

1 pc. after 10 days after 30 days after rewinding rewinding rewinding

1.0 2.1

0.5 0.6

0.4 0.5

0.4 0.5

This makes it clear that the ancestors of the Invention of horgostollten yarns corresponding to the increase in the elapsed time, a smaller increase in lumpiness exhibit. This means that they have less tackiness.

In the examples above, certain elastomeric yarns with certain chemical structures have been given. However the method of the invention is not limited to these yarns, but rather more generally to elastomeric yarns Yarns widely applicable.

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Claims (5)

Claims π J Process for producing an elastomeric endless yarn with reduced stickiness and improved dynamic properties, characterized by the combination of the following successive process steps: Sehiaelzeelzetrudung a segmented elastomer from the opening or the openings of a spinneret? quenching of the extruded elastomer for solidification, whereby a continuous yarn is formed 3 successive Ve2? stretching of the continuous yarn formed for elongation to at least P 30 tfo its original length 3 relaxation of at least 50 in the elongation of the yarn and winding the yarn on a bobbin. 2. The method according to claim 1, characterized in that " the percentage elongation is at least 50 *. 3. The method according to claim 1, characterized in that the percentage stretch is $ 100 to $ 500, 4. The method according to claim 1, characterized in that the percent relaxation of the stretch is at least 75 5 '. . 5. The method according to claim 1, characterized in that the percent relaxation of the stretch is at least 80 ^. 6. The method according to claim 1, characterized in that the yarn is quenched during the drawing stage. 7. The method according to claim 1, characterized in that the stretching stage is carried out in several stages. 009827/1876 6. Method according to claim 1, characterized in that the relaxation stage of the stretching is carried out in several stages will. 9. The method according to claim 1, characterized in that at least two series of the stages of stretching and relaxation are carried out in sequence. 10. The method according to claim 1, characterized in that the elastomeric endless yarn is an elastomer with an elongation at break, elongation of at least 100 $, a springback at 100 Jo elongation of at least 80 y * ^{un <} 3 an initial modulus of at most ns 1 g / di,; t. 11. Demonstrates: according to claim 1 , characterized in that the el ^ tonerο endless yarn is an elastomer with an elongation at break of e ^! v _; :, A resilience of at least 90 100 fö .Dehnung fa and an initial modulus of not more than 0, 5 g / u 200 1000 IjIs f'i. 12. The method according to claim 1, characterized in that the Segnent EJastomer consists of a polyurethane. 009827/1876