DE2909785A1 - PROCESS FOR THE MANUFACTURING OF FIBERS OR FIBERS FROM POLYMERIZED CONTAINING ACRYLIC NITRILE WITH INCREASED WATER-RETENTION CAPACITY - Google Patents

Description

- ο -

Lenzing man-made fiber

Corporation

in Lenzing, Austria

Process for the production of threads or fibers from acrylonitrile-containing polymers with increased water retention capacity

909840/0582

29Q9785

The invention relates to a method for producing threads or fibers from an acrylonitrile homopolymer or an acrylonitrile copolymer with a content of at least 50% acrylonitrile _units which have a water retention capacity of at least 30%, a tear strength of at least 2.5 cN / dtex and an elongation at break of at least 25 %, by dry or wet spinning of a solution of the polymer in a non-aqueous spinning solvent and optionally fiber formation by evaporation of the solvent in a spinning shaft or by precipitation in an aqueous spinning bath and subsequent drawing and washing of the threads or fibers, where the spinning solution is oligomeric Auxiliaries are added.

There are processes for the production of hydrophilic threads or fibers from polymers consisting of or containing acrylonitrile known by the way of dry or wet spinning. For example, according to DE-OS 20 61 213, hydrophilic fibers are produced by monomers carrying hydrophilic functional groups are polymerized into polyacrylonitrile "and the copolymer is wet-spun. It can also be used to increase the hydrophilic behavior of the threads or fibers of a polyacrylonitrile homopolymer or a polyacrylonitrile copolymer before spinning others more hydrophilic polymers, e.g. polyethylene oxide methacrylate, mixed in will. It is also known to treat wet-spun polyacrylonitrile fibers in the swollen state with aldehyde and acid, as described in U.S. Patent 3,733,386 to determine hydrophilicity to improve. Another known method of making hydrophilic threads or fibers from synthetic Polymers by wet spinning exist according to DE-OS 26 07 996 in that the dope is a low molecular weight substance adds, which is readily miscible with the spinning solvent and the precipitant, but none for the fiber-forming polymer Represents solvent. In this process, the added substances are dissolved out after stretching Threads or fibers with very small, water-absorbing cavities.

In the case of antistatic acrylonitrile polymers, it is in accordance with also known from AT-PS 320 836, as an additive, oligomeric phthalic acid esters containing polyalkylene oxides in the ester group, to use. - .-

To improve the mechanical properties, in CH-PS 469 823 describes the addition of, inter alia, polyadipates to acrylonitrile polymers.

In the known dry spinning process for the production of hydrophilic threads or fibers, a liquid is used for Spinning mass added, which has a higher boiling point than the spinning solvent used, and with the spinning solvent and the washing liquid is miscible with water. This Additive is washed out after stretching and leaves cavities, which give the threads or fibers a certain water retention capacity to lend.

In the known processes, especially in the wet spinning process, is the achievement of a microporous structure and thus the desired hydrophilic properties without special Difficulties are possible, but the porosity worsens the technological properties of the textile (see Textile Research Journal, January 1963, page 13). This is probably responsible for the fact that in all cases where a Spinning solution is spun, the solvent of which is soluble in the spinning bath, osmotic effects occur, which in addition to very Small pores often also create larger cavities. Such larger cavities occur e.g. in the already mentioned DE-OS 26 07 996 on. The tensile strength and elongation at break of porous threads and fibers, in addition to micropores, also such larger cavities included, but not satisfactory; as a rule, they are only 2 cN / dtex and below 30%, which is what the performance properties are such threads or fibers impaired.

The present invention aims to avoid these disadvantages and has the object of providing a method for production of threads and fibers made of acrylonitrile existing or containing polymers with high water retention capacity to create whose textile properties, in particular tear resistance, Elongation at break, loop strength and abrasion resistance improved compared to the known hydrophilic threads and fibers are.

This object is achieved in a method of the type specified in that the spinning solution based on the polymer 1 to 100%, preferably 5 to 50% of compounds of the following groups of substances: polyamides, polyvinyl alcohol,

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Polyamines, polyurethanes, polycarbamates, polystyrene, polyvinyl carbonate, Polymethylene oxide, polyethylene oxide, polypropylene oxide, polyvinyl acetate or low molecular weight copolymers of these Oligomers, as well as cellulose esters and ethers and / or starch derivatives, with a molecular weight of at least 2000 to a maximum of 10,000 can be added.

Dimethylformamide, dimethylacetamide and dimethyl sulfoxide can be used as the spinning solvent.

The presence of hydrophilic groups in the oligomeric additives is expedient.

The additives to be used according to the invention for the spinning solution have the effect that by their intercalation between the fibers formed in the spinning bath or spinning shaft Structural elements and, due to their possible slow washing out during the stretching or washing treatment, stable micro-cavities develop.

The amount of additives depends on the desired hydrophilicity. The upper limit of the additive is determined by the Compatibility with the spinning solvent and determined by the possible precipitation effect for the polymer. In the case of the Experience has shown that wet spinning requires higher amounts and a higher molecular weight of the oligomeric additive than in the case of dry spinning. This finds its explanation in the fact that with dry spinning already in the primary spinning process further fiber consolidation occurs, which is why tolerate any earlier leaching in the aftertreatment is bar without the cavities collapsing in the drying process.

The spinning mass provided with the additives according to the invention is either spun in precipitants, such as e.g. Spinning baths containing water at a temperature between 5 and 50 C; the preferred spinning temperature is between 5 and 20 C; or in a conventional spinning shaft at a temperature of the spinning solution between 85 and 110 C with evaporation — of the Spinning solvent by means of a suitably heated inert spinning gas.

The spun filaments or fibers are then stretched in a boiling solution containing 20% of the spinning solvent used in addition to the precipitating agent, usually water, preferably contains. 5 Here, the additive can be partially dissolved out of the fiber. In the subsequent

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Washing treatment with the precipitating agent which dissolves the spinning solvent, preferably water, can remove the more difficult soluble oligomeric additives take place without being a condition. This washing treatment is usually carried out at the boiling point of the precipitant. The further process steps, such as crimping and cutting into staple fibers, take place in conventional way.

In addition to good fiber properties, it is particularly easy to dye of the microporous fibers produced according to the invention.

The method according to the invention is used in the following examples explained in more detail. As a measure of the comfort of textiles worn close to the skin, the water retention capacity is a meaningful one The criterion is, in addition to tear strength and elongation at break, the water retention capacity is also listed. This is determined as follows:

The samples are weighed into a dry centrifugal vessel. After weighing, the centrifugal vessel is poured in from below with water, to which 1 g of wetting agent per liter is added became. The network duration is 2 hours. When the wetting is complete, the centrifugal vessel with its wetted fiber content is removed Centrifuged for 20 minutes at 3000 rpm, the water not absorbed by the pore structure of the fiber through the Inlet opening can drain. After centrifugation, the centrifugal vessel is weighed to determine the weight of the moist fiber material (fiber plus retained water). Evaluation:

WRV (water retention capacity) = ψ x 100, where mf das

Weight of the moist fiber material and mtr is the weight of the dry fiber material.

Example 1: 180 g of polyacrylonitrile powder were put into a solution of 20 g of polyvinyl acetate (molar weight 5000) in 800 g of dimethylformamide registered. The mass was heated to 90 ° C. over the course of 2 hours with stirring, and this was continued for a further 2 hours Maintain temperature, whereby a colloid-disperse mixture was formed. This was degassed by evacuation and then through a 150-hole nozzle pressed into a bath, which consisted of a 60% solution of dimethylformamide in water and a temperature of 15 C. The threads were at a speed of 4 m / min withdrawn and then at 98 ° C in a 20% solution of

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Dimethylformamide in water 1:10 stretched. Thereupon was with Washed 98 ° C hot water, finished and dried at 14O ° C.

The threads obtained in this way showed a circular cross-section with a uniform micropore structure in the light microscope. The pores were below the resolvability of the light microscope s. ■:

The following data were determined on the threads:

Water retention capacity: 46%

Titer: 3.3 dtex

Tear strength: 26 cN / tex

Elongation at break: 30%

Example 2: 180 g of polyacrylonitrile powder were added to a solution of 10 g of polyvinyl acetate (molar weight 9000) in 810 g of dimethylformamide. ^{The mass was heated to 90 °} C. within 2 hours while stirring and left at this temperature for a further 2 hours, a colloid-disperse mixture being formed. This was degassed by evacuation and then pressed through a 150-hole nozzle into a bath, which consisted of a 60% solution of dimethylformamide in water and had a temperature of 15 ° C. The threads were drawn off at a speed of 7 m / min and then stretched 1: 8 at 98 ° C. in a 20% strength solution of dimethylformamide in water. It was then washed with hot water at 98.degree. C., finished off and dried at 140.degree.

The threads obtained in this way showed a circular cross-section with a uniform micropore structure in the light microscope. The pores were below the resolution of the light microscope.

The following data were determined on the threads:

Water retention capacity: 30%

Titer: ■: 3.3 dtex

Tear strength:. 29 cN / tex

Elongation at break:. 3O%.

Example 3: 180 g of polyacrylonitrile powder were put into a solution of 50 g of polyglycol ether (molar weight 7000) in 730 g of dimethylformamide registered. The mass was heated to 90 C with stirring and left at this temperature for 2 hours, with one clear solution resulted. This was through a 150-hole nozzle in

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pressed a bath, which consists of a 50% dimethylformamide solution consisted of water and had a temperature of 15 C. The threads were pulled off at a speed of 4 m / min and

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then at 98 C in a 20% solution of dimethylformamide stretched 1: 7 in water. The cable was then passed through an alcohol bath and also in an alcoholic solution aviviert; it was dried at 100.degree.

The threads obtained in this way showed a kidney-shaped cross-section in the light microscope, interspersed with a very uniform one Pore structure. The pores were below the resolvability of the light microscope.

Threads with the following data were obtained:

Water retention capacity: 40%

Titer: 3.3 dtex

Tear strength: 30 cN / tex

Elongation at break: 28%

Comparative example: 180 g of polyacrylonitrile powder were in 820 g of dimethylformamide dissolved within 2 hours with simultaneous stirring at 90 ° C. to give a clear solution. This solution was pressed through a 150-hole nozzle into a bath, which consisted of a 60% solution of dimethylformamide in water and had a temperature of 15 C. The threads were with withdrawn at a speed of 4 m / min and then at 98 C in a 20% solution of dimethylformamide in Water stretched 1: 8. Then 98 C hot water was used washed, finished and dried at 140.degree.

The threads produced in this way showed a kidney-shaped cross-section under the light microscope, with a compact pore-free structure.

The determined data:

Water retention capacity: 2%

Titer: 3.3 dtex

Tear strength: 32 cN / tex

Elongation at break: 30%

Example 4: Line spinning solution obtained by introducing 28 parts of a polyacrylonitrile polymer powder into a solution of 4 Parts of polyethylene oxide (mol. Wt. 4000) in 68 parts of dimethylformamide and by subsequent heating at 90 ° C for 2 hours

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were prepared with stirring, was among those for normal polyacrylonitrile fibers known conditions from a 200 χ 175 / im Nozzle dry spun. The cables (single titer 11.6 dtex) were withdrawn at a speed of 180 m / min, on spools collected and combined into a 40-coil gate. Then was stretched 1: 4.4 in boiling water, washed for 2 minutes in hot water, finished and with a shrinkage approval of 25% dried on a sieve drum dryer at 140 ° C.

The threads obtained showed that for dry spun in the light microscope Fibers with the usual jacket-shaped cross-section, but interspersed with a uniform microporous structure.

The textile data obtained were as follows:

Water retention capacity: 28%

Titer: 3.3 dtex

Tear strength: 25 cN / tex

Elongation at break: 25%

Example 5: A spinning solution obtained by adding 27 parts of a polyacrylonitrile polymer powder to a 3-part solution of a partially saponified polyvinyl acetate (mol. wt. 5000) in 7O Share dimethylformamide and then heat for 2 hours at 90 ° C, was among those for normal polyacrylonitrile fibers known conditions dry-spun from a 200 χ 175 nozzle. The manhole cables with a single titer of 10.5 dtex were withdrawn at 200 m / min, collected on bobbins and combined to form a 40 coil gate.

Then it was stretched 1: 4 in boiling water, 2 minutes in Washed with hot water, finished and dried with a shrinkage approval of 25% on the sieve drum dryer at 140 ° C.

The following textile data were determined on the threads:

Water retention capacity: 32%

Titer: 3.3 dtex

Tear strength: 29 cN / tex

Elongation at break: 25%

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Claims (3)

Claims 1, a process for the production of threads or fibers from an acrylonitrile homopolymer or an acrylonitrile copolymer with a content of at least 50 % acrylonitrile units, which have a water retention capacity of at least 30%, a tear strength of at least 2.5 cN / dtex and an elongation at break of at least 25% , by dry or wet spinning of a solution of the polymer in a non-aqueous spinning solvent and optionally fiber formation by evaporation of the solvent in a spinning shaft or by precipitation in an aqueous spinning bath and subsequent drawing and washing of the threads or fibers, oligomeric auxiliaries being added to the spinning solution are, characterized in that the spinning solution based on the polymer 1 to 100%, preferably 5 to 50% of compounds of the following groups of substances: polyamides, polyvinyl alcohol, polyamines, polyurethanes, polycarbamates, polystyrene, polyvinyl carbonate, polymethylene oxide, polyethylene oxide, poly propylene oxide, polyvinyl acetate or low molecular weight copolymers of such oligomers, as well as cellulose esters and ethers and / or starch derivatives, with a molecular weight of at least 2000 to at most 10,000 are added. 2. The method according to claim 1, characterized in that an additive is used in the manufacture of the threads by wet spinning is used, which is insoluble or sparingly soluble in the precipitant. 3. The method according to claim 1, characterized in that an additive is used in the manufacture of the threads by dry spinning is used, which is soluble in the subsequent washing with aqueous washing liquids. 9098 * 0/0582 \ COPY