DE1494689C3 - Process for the production of multi-component shutters or lasers from acrylonitrile copolymers - Google Patents

Description

CH = CH ₂

wherein R ₁ and R _{2 are} hydrogen or a lower alkyl group or R ₁ and R ₂ are connected to one another to form a five- or six-membered ring, or a compound of the general formula

O , C - L. - C -

R ₄

in which R ₃ , R ₄ and / or R _{5 are} hydrogen or a lower alkyl group or R ₄ and R ₅ are connected to one another to form a five- or six-membered ring, is polymerized.

3. Process according to Claims 1 and 2, characterized in that the stretched Subjected fiber to a shrink treatment for curl development in a hot medium stretched to remove crimp, spun into a yarn and then another Subjected to shrink treatment for curl development.

4. The method according to claims 1 and 2, characterized in that the drawn fiber is subjected to a heat treatment at a temperature below 100 ⁰ C in the relaxed state, spun into a yarn and then subjected to a shrink treatment to develop crimps.

5. The method according to claims 1 and 2, characterized in that the stretched The fiber undergoes heat shrink treatment at a temperature higher than the second transition temperature Fiber subjects under such a tension that the crimp number due to the shrinkage difference between the polymer components is less than 80% of the crimp number, which is fully developed in the tension-free state, and that the shrinkage of the mixed fiber is greater than that of the less shrinking polymer component.

The invention relates to the production of improved multicomponent threads or fibers from acrylonitrile copolymers with reversible crimp when treated with water.

Various reversible crimp multicomponent fibers are known. A very typical fiber of this type is described in British Patent No. 8,69,301. This fiber is a mixed fiber with at least two eccentrically mounted polymer components, one of which contains a greater amount of ion-dissociable groups than the other and in this way gives the fiber a reversible crimp. As monomers which contain the greater amount of the ion-dissociable group, z. B. acidic monomers such as sodium styrene sulfonate are used. However, such a fiber has the disadvantage in dyeing that a cationic substance, e.g. B. a ■ canonical dye or a cationic retarder, affects the fullness of the end product, so that special operations are necessary to obtain the fullness. In addition, the crimping of the fiber in hot water disappears already 7O ⁰ C, and can consequently products from this fiber its dimension not keep if you do not carefully washes special. The water-reversible crimp of a mixed fiber, in which a component contained in the fiber contains a hydrophilic group which cannot be dissociated into ions, is described in British Patent 8,969,955.

A mixture of a water-absorbing polymer, such as poly-N-vinylmethylformamide, is used for this fiber or poly-N-vinylpyrrolidone, and a hydrophobic polymer, such as polyacrylonitrile, are used. In the case of a fiber which contains such a water-absorbing polymer, the polymer deliquesces when spinning in an aqueous spinning bath or when drawing or after treatment with water, and the melted polymer collects on the contact surface with the fiber, e.g. B. on a guide device, with the result that the fiber breaks and a significant adverse effect on process stability The result is. This disadvantage can be caused by copolymerizing acrylonitrile and a hydrophilic monomer can be overcome instead of the fiber by mixing in the hydrophilic Makes polymers hydrophilic.

A known process in which a mixed polymer of acrylonitrile and a non-dissociable hydrophilic monomer, ie a hydrophilic neutral monomer, is used as one component of a mixed fiber, is a dry mixed spinning process of polyacrylonitrile and a mixed polymer of acrylonitrile and either N-vinylpyrrolidone or N- ^V inylmethylformamide in one

Weight ratio 90:10 (see British patent specification 8 96 955). It was found that the mixed fibers had essentially no water reversibility demonstrate. This fact agrees with information in the cited patent specification, where it is said that Such polymer combinations cannot produce fibers with high water-reversible crimp.

It was possible to overcome the above disadvantages and create new water-reversible compounds To manufacture fibers.

The invention therefore relates to a method for producing multi-component threads or -fibers made from acrylonitrile copolymers through simultaneous spinning of at least two spinning solutions, containing different acrylonitrile polymers in a precipitation medium, stretching and Shrink treatment of the threads obtained and, if appropriate, repeated shrink treatment of the fibers or threads in the form of the yarns, knitted fabrics or woven fabrics produced from them, which is characterized by this is that one of the spinning solutions is the solution of a hydrophobic, 80 to 96 percent by weight Acrylonitrile-containing copolymer without a hydrophilic neutral comonomer and as a second spinning solution, the solution of a hydrophilic acrylonitrile copolymer with a copolymerized one Proportion of 5 to 30% by weight of a hydrophilic neutral monomer used.

In addition to the hydrophilic neutral monomer, one can also use neutral monomers that Form copolymers with acrylonitrile, such as methyl acrylate, methyl methacrylate, vinyl acetate, vinyl chloride, Vinylidene chloride or styrene as well as one which can be dissociated into ions to improve the colorability Monomer, such as p-styrene sulfonic acid, methallyl sulfonic acid, Allylsulfonic acid, acrylic acid, itaconic acid, maleic acid, vinylbenzoic acid, 2-vinylpyridine, 2-methyl-5-vinylpyridine or their salts.

If the content of the hydrophilic neutral monomer in the hydrophilic component is higher than 30% by weight, the fiber obtained shows high curl reversibility, but the fiber properties fall off, especially the tear length and the hot water module.

When the hydrophilic component contains a monomer which can be dissociated into ions, it is usually intended to also the hydrophobic component (s) in ion-dissociable monomer in an approximately equivalent amount contain.

According to the invention, a random copolymer is preferably used as the copolymer used.

The hydrophilic neutral monomer used is a water-soluble monomer that cannot be dissociated into ions denotes which is copolymerizable with acrylonitrile via an unsaturated ethylenic group is. The monomer should be more than 15 percent by weight be soluble in water at 25 ° C, or a homopolymer from the monomer should have an absorption capacity for humidity of over 6% at 25 ° C and 65% relative humidity.

The hydrophilic neutral monomer can either be incorporated into the polymer by ordinary copolymerization be incorporated, or it can be formed in the polymer by hydrolysis. In the latter This is the case, for example, with vinyl alcohol. However, if the hydrophilicity is determined by means of a hydroxyl group such as in the case of the use of vinyl alcohol, care must be taken that there is no hydrogen bond is formed in the polymer during the manufacturing process for the fiber. Suitable hydrophilic neutral monomers for the Acrylonitrile copolymers which can be used according to the invention are organic acid amides and N-substituted amides organic acid amides with ethylenically unsaturated ones that are copolymerizable with acrylonitrile Groups, and their derivatives. Are the organic ones

ίο acids from which the named compounds are derived are saturated organic acids, suitable monomers are those that are ethylenically unsaturated Contain N-substituents and the general formula

O

R ₁ -CN:

CH = CH,

correspond, in which R ₁ and R _{2 are} hydrogen or a lower alkyl group or R ₁ and R _{2 are} directly connected to one another, so that a five- or six-membered ring is formed.

The compounds of this formula include e.g. B. N-vinyl-N-methylformamide ^ -Vinylmethylacetamid, N-vinyl pyrrolidone, N-vinyl caprolactam and N-vinyl piperidine.

Particularly suitable compounds are those which are derived from unsaturated organic acids and the general formula

H ₇ C = CC-N '

correspond, in which R ₃ , R ₄ and R _{5 are} hydrogen or a lower alkyl group, or R ₄ and R _{5 are} directly connected to one another, so that a five- or six-membered ring is formed. Such compounds include, for example, acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-acrylmorpholine and N-acrylthiomorpholine. Further examples of equally effective compounds in which one or more of the groups R ₃ , R ₄ and R _{5 of} the formula are neither hydrogen nor alkyl groups are methylolacrylamide (R ₅ = - CH ₂ OH), a - acetylaminoacrylamide (R ₃ = NHCOCH ₃ ) and itaconic acid _{amide (R 3} = -CONH ₂ ).

Those hydrophilic, neutral monomers are suitable which are ethylenically unsaturated and besides one or more

- C - Nv groupings

contain, with those whose ratio of the remaining carbon atoms to

- C - Nv group
5: 1 or less are particularly effective.

The hydrophilic components are acrylonitrile copolymers which contain one or more of the hydrophilic neutral monomers mentioned. A fiber which has been obtained by spinning and drawing the hydrophilic component alone shows a reversible change in length between the dry state at 20 ^° C. and the wet state at 80 ^° C. It is desirable for the invention that the amount of the reversible change in length of a fiber of the hydrophilic component is at least 0.4% larger than that of the component of the other dope.

The amount of the reversible change in length of a single component fiber varies depending on the type of hydrophilic neutral monomer contained in the component and the type used Spinning process, but is significantly influenced by the content of hydrophilic neutral monomer. The difference in the reversible change in length between fiber-forming components can therefore mainly due to the difference in the content of hydrophilic neutral monomer between the components to be determined.

In the context of the invention, a mixture of several hydrophilic acrylonitrile copolymers can also be used be used. In addition, the hydrophilic copolymer component can be a fiber contain flame retardant polymer, such as polyvinyl chloride.

The hydrophobic acrylonitrile copolymer must not contain more than 96 percent by weight of acrylonitrile units included, otherwise the degree of shrinkage will be too high and thus the shrinkage difference between hydrophilic and hydrophobic copolymer components, which are decisive for the reversibility of crimps influenced, cannot be kept sufficiently low. As copolymerizable monomers are suitable e.g. B. acrylates, methacrylates, vinyl alcohol esters, vinyl chloride, vinylidene chloride, styrene and methacrylonitrile.

The polymer or copolymer mixed with said acrylonitrile copolymer should be, includes ζ. Β. Polyacrylonitrile, polyvinyl chloride, cellulose acetate, a graft polymer from Cellulose acetate and acrylonitrile, a graft polymer of a polyvinyl alcohol derivative and acrylonitrile or a block polymer of acrylonitrile and methyl acrylate. The use of an acrylonitrile copolymer as a hydrophobic component results in an improvement in the dyeability as a simultaneous side effect, the stability of the polymer solution towards numerous solvents and its spinnability.

The one on the polarity of the nitrile group of acrylonitrile copolymers based intermolecular forces are due to the presence of the comonomers weakened. The result is a fiber with a higher shrinkability than polyacrylonitrile with the same molecular weight if the fibers are spun under the same conditions and stretched. The shrinkage differs depending on the medium and the temperature that occurs at the Shrink treatment can be applied. For example, a fiber made from an acrylonitrile-vinylidene chloride copolymer subjected to heat shrinkage with steam, there is only a small difference in the compared to a polyacrylonitrile fiber Degree of shrinkage observed; however, the heat shrinkage is carried out in an aqueous phenol solution through, the copolymer shows a much higher shrinkage than the polyacrylonitrile. Self when a single component is used for fiber production, the fiber only being a small one Shows a difference in shrinkage compared to a polyacrylonitrile fiber, in practice there is sometimes a large one higher shrinkage of the former fiber compared to the latter when combined with the hydrophilic fiber Component mix-spun.

It has been found that if you have two acrylonitrile polymers mix-spins, draws and shrinks with different shrinkability, the component with the smaller shrinkage increases it beyond the original shrinkability, while the higher shrinkage component has a smaller shrinkage compared to the original Has shrinkability.

The hydrophobic component used according to the invention generally shows a higher degree of shrinkage as polyacrylonitrile when spun into fibers.

However, it is necessary that the hydrophobic

■ Copolymer component with the hydrophilic one Copolymer component is spun together to form a crimped fiber with high water reversibility to obtain.

It is believed that this effect is related to the heat shrinkage difference Δ HS , which is also confirmed by the following fact.

Namely, it has been shown in British Patent 8,969,955 to have excellent crimp reversibility is obtained when a mixture of 90% polyacrylonitrile and 10% poly-N-vinylpyrrolidone blend-spun with polyacrylonitrile, but remarkably low crimp reversibility when a copolymer of 90% acrylonitrile and 10% N-vinylpyrrolidone with polyacrylonitrile is mixed spun. If you now have the mentioned mixed polymer and the mixed polymer with the N-vinylpyrrolidone content independently wet spun from each other, stretched the fiber obtained under the same conditions and then the Measures shrinkage of the fibers in boiling water, then the fiber from the polymer mixture has a Shrinkage of 15.3%, i.e. close to the 10.4% shrinkage value of spun under the same conditions and drawn polyacrylonitrile fiber, while the copolymer fiber is a pronounced one shows high shrinkage of 32.4% in boiling water. Accordingly, the polymer

- the mixture and the copolymer have a shrinkage difference compared to polyacrylonitrile of 4.9 or 22.0%. It can be concluded that high curl reversibility cannot be obtained if that Copolymer is mixed-spun with polyacrylonitrile, since the difference in shrinkage is too great. As can be seen from this example, one of the differences is that of the invention Process obtained mixed fibers compared to those of British Patent 8 96 955 in that the hydrophobic component is not polyacrylonitrile, but an acrylonitrile copolymer with a Acrylonitrile content is less than 96 percent by weight. This is one of the features that are essential to the invention.

For example, a combination of polymer components is made in the patents mentioned Polyacrylonitrile and a copolymer of acrylonitrile and N-vinylpyridine in a weight ratio

of 90:10 is used, while according to the invention a combination of polymer components of the composition 90:10 acrylonitrile-N-vinylpyridine copolymer and 93: 7 acrylonitrile-vinyl acetate copolymer is used.

According to the invention, the combination of the polymer components is usually selected in such a way that that the hydrophilic component receives a higher shrinkage. However, it is also possible to reduce the shrinkability to enlarge the hydrophobic component. In this case, a so-called negative curl reversibility becomes obtain.

According to the invention, fibers with high crimp reversibility are generally obtained in a simple manner when the shrinkage difference I HS between the hydrophilic and the hydrophobic components is less than 20%.

According to the invention there are at least two spinning solutions spun by any dry, wet or semi-melt process od. The like., The The type of spinning is not particularly limited. The spun fiber can after a single pass be brought into the precipitation bath through the air, while the precipitation bath is above a critical concentration is held. In this case, the adhesion of each component improves. The critical focus of precipitation baths from dimethylformamide - water, dimethylacetamide - water or dimethyl sulfoxide - water is around 75%, but varies depending on the temperature. The critical one The concentration in a nitric acid-water precipitation bath is around 40%.

Any suitable solvents can be used in the preparation of the spinning solutions, organic solvents, such as. B. dimethylformamide, dimethylacetamide and dimethyl sulfoxide, aqueous nitric acid solutions or aqueous solutions of inorganic salts such as zinc chloride and Rhodanide usually find use.

According to the invention, two or more spinning solutions are spun eccentrically. The eccentric one Spinning can be carried out in such a way that a mixed fiber is obtained, the so-called side on Side arranged or corresponds to the core sheath type. With regard to the slight puckering the side-by-side type is preferred.

Any conventional mix-spinning apparatus can be used as the spinning apparatus will. For the laterally assembled fibers the device is according to the British patent 8 96 955 suitable, while for the jacketed type, for example, the device according to the United States patent 29 31 091 can use.

Spinning can be carried out by passing through part of the spinneret orifices at least two spinning solutions containing acrylonitrile polymer are pressed eccentrically while one is through the other openings only press a solution. In this way, yarns are mixed and not single-component spun simultaneously from at least two spinning solutions.

The ratio of each component in the cross section of the mixed fibers which can be produced according to the invention can fluctuate in each mixed fiber. According to the invention, therefore, a mixed fiber is formed, which because of the low content of a component independently no water reversible crimp by shrink treatment can form in a relaxed state. But a mixed fiber is also spun, which forms many water-reversible crimps because of the proportion of one component in the fiber cross-section is close to 50%.

It is preferred according to the invention to carry out the spinning in such a way that there is a mixing ratio according to the formula

Mixing ratio =

Number of mixed threads with

Ripple development

below the total number of threads

Total number of

spun threads

receives from 20 to 85%.

The mixed fiber of two components according to the invention is explained in more detail below.

In order for a mixed fiber to develop a substantial amount of curl, the area that a component is supposed to develop occupies in the fiber cross-section, generally 3 to 96%, preferably 5 to 95%. Amounts to If this area accounts for 30 to 70%, a fiber is obtained which is extremely numerous Pimples developed with ordinary relaxation treatments. In contrast, the fiber develops less Crimps when the cross-sectional area of a component is less than 10%. In the first case the object of the invention is achieved even if the mixing ratio is low, for. B. is 20%; in the the latter case is a high mixing ratio of e.g. B. 85% required.

If the mixing ratio is less than 20%, the threads obtained according to the invention develop less curl, and therefore a filament cord with great fullness is not available.

It is easy to understand that a mixed fiber develops curl by a shrinking treatment, Surprisingly, however, even a single component fiber according to the invention develops crimp when shrinking. Even if the crimps thus formed are once due to mechanical stress have disappeared, they are re-treated z. B. with boiling water or steam restored.

It has been found that in general two or more threads with different shrinkability, that are close to each other develop puckering in the shrink treatment.

One or more individual component threads and eccentrically mounted mixed threads, which according to the invention consist of at least two components, have different shrinkability. Is furthermore the proportion of each component in the mixed threads is different, so the shrinkability also differs of mixed threads from each other. It follows that all threads including the individual component threads Develop crimp when the threads obtained by the method according to the invention be shrunk.

When a yarn is shrunk from the tow obtained according to the present invention, reason occurs the difference in shrinkage between the threads shows a remarkable thread movement in the yarn, with the result that the yarn has a high body and an excellent handle. High shrinkage Threads are in a highly tensioned state in the yarn and contribute to the dimensional stability of the Yarn and excessive elongation of the

509 636/323

Preventing yarn from being weighed down slightly. Therefore it is made from the threads spun according to the invention manufactured yarn stable to applied tension when dried or subjected to wet heat will. This shows a great advantage of the invention. As a spinning device can be advantageous Use spinnerets in which a distributor plate with holes is arranged. With such spinnerets one dope hits the upper surface of the distributor plate and passes through the holes and on the lower surface of the distributor plate. At the same time, the second spinning solution is laterally in the Distribution plate in a space arranged between the upper and lower surfaces of the distribution plate fed in. As a result, the streams of the first spinning solution flowing through the holes with the Surrounding the second spinning solution without the two spinning solutions mixing with one another. At Sheathed streams then emerge from the lower surface of the distributor plate. These currents then occur through the spinneret orifices. This gives threads arranged side by side next to threads from the respective spinning solutions. If such devices are used, one can easily determine the number of Increase orifices on the spinneret surface and thus improve productivity considerably. Even this is an advantage of the invention. It is also possible to use a conventional spinneret for mix spinning to use by modifying the opening arrangement.

The spun threads can be post-treated by conventional methods, such as. B. stretching, Washing, drying and curling shrinkage. However, it becomes a crimped fiber obtained with particularly excellent water reversibility in a wet spinning process, if one spun under such conditions that the degree of swelling (swelling weight / dry weight) of the coagulated fiber rises above 200% and is preferably 250 to 700%. A coagulated fiber with a The degree of swelling in this area is determined by the choice of conditions in the precipitation bath made of dimethylformamide— Water, dimethylacetamide - water, dimethyl sulfoxide - water, Nitric acid — water or rhodanide — water easily preserved. In the case of using a precipitation bath made of dimethylacetamide-polyethylene glycol however, the degree of swelling is below 200%.

The coagulated fiber is usually washed with drawing in hot water and then dried or washed, dried and then stretched hot. The stretching can also be carried out in two stages before and after drying. Mainly one is stretched to get the one you want to impress physical properties of the fiber. Usually the coagulated fiber becomes stretched four to ten times in total. The stretching time affects the shrinkability each component of the composite fiber after drawing. Since the fiber is in a drying or Heat set in the hot stretching step, the temperatures used in this step are important factors to influence the shrinkage.

The drawn fiber is exposed to dry or wet heat, usually in a relaxed state or exposed above 100 ° C, whereby it shrinks and ripple developed. It can also be shrunk below 100 ° C. in an aqueous phenol solution will.

The shrinkage conditions naturally have a great influence on the shrinkage of each component nent of the mixed fiber. If the shrinkage treatment is carried out under such conditions that c If the fiber is not loaded, the fiber develops crimps according to the shrinkage diff components. In some cases, α curl number is used in view of the later Han Habitation of the fiber too large under the conditions mentioned. It is therefore preferred to use the number reduce the puckering by regulating the various conditions that the shrinkage affect each component.

In general, it is desired that the Kraus treatment number is less than 50 to 25 mm, preferably it is 10 to 30 to 25 mm.

If the shrinkage treatment is performed under very poor conditions such as: B. carried out below 100 ⁰ C then the fiber does not develop any crimp. But after spinning, knitting or weaving it can:

If they are then free to hang under harsh thermal conditions, develop puckering; will.

After the crimp has developed, the bevel can be stretched to remove the crimp; spun, knitted or woven and then treated again for crimping. Optional came the shrink treatment and stretching; repeated several times. The shrinkage can treatment be carried out under 100 ⁰ C, wöbe under suitable spinning and Nachbehandlungsbe conditions the fiber at room temperature crimp may develop, resulting from the remaining shrinkage ability of the drawn fiber shrinkage without special treatment.

Preferably, if harder is thermally; Conditions are required to improve the Fasereigenschaftei used for the shrinking treatment ge sättigter water vapor of more than 11O ⁰ C The treatment can in this case in an autoclaved \ by repetitively alternately applying a: be conducted vacuum and vapors.

It has also been found a very useful relaxation method for mixed fibers, where there; called overcontraction phenomenon is used that consists in that the low shrinkage Fiber component of the mixed fiber shrinks beyond the original shrinkage capacity which method can reduce the crimp number.

It was namely an acrylonitrile mixed fiber, which consists of at least two polymer components mil different heat shrinkage existed, stretched and then a heat shrinkage at one Temperature which was above the transition temperature of the second order of the fiber, subjected to the Fiber was subjected to such a tensile stress that the number of due to the difference in shrinkage crimps developed between the components was less than 80% of the number that developed without Application of a voltage would have been developed and, moreover, the mixed fiber shrunk more than the shrinkage of the low-shrinkage component. As a result, the To improve dyeability, knot strength, elongation and fibrillation resistance of the fiber, while the curl development was controlled or avoided.

The thread tension is preferably dimensioned in such a way that the difference in heat shrinkage due to the heat shrinkage the number of crimps developed in the components of the mixed fiber actuates less than 80% of the crimps, which is achieved without tension, and moreover the fiber shrinks more than the low shrinkage Component does. Is the stress applied during heat shrinkage greater than the above, e.g. B. when the fiber shrinks only slightly due to a high tension or when the fiber shrinkage is less than that of the low shrinkage component, it becomes natural no crimp developed, but rather the fiber properties are considerably impaired, surprisingly no curl will be developed at all if the fiber tension is considerably lower than that critical voltage (upper limit), e.g. B. when the voltage is about a quarter of the critical voltage amounts to. In addition, in this case, the shrinkage of the composite fiber is larger than that the low shrinkage component. One must therefore assume that there is an overcontraction in the low shrinkage component has taken place.

If the tension becomes even lower, ripples will indeed develop during the heat shrinkage, but in far fewer numbers than if no voltage had been applied. In general, the Crimp number is reduced to a large extent if only a slight fiber tension is generated, and can therefore can be optionally regulated by the amount of tension. However, the tension is excessive low, the number of ripples increases after treatment with boiling water in such The extent to which the crimp is equivalent to that obtained by treating the untensioned fiber sustains as the ubercontractor of the low shrinkage component passes. Besides, it is technically difficult to regulate the tension by yourself, whereby the crimp is developed unevenly. Therefore, the shrinkage treatment is preferably carried out when there is so much tension imposes on the fiber that the crimp count is less than 80% of the crimp of the untensioned fiber amounts to. This means that the tension, which causes 80% of the crimp number of the untensioned fibers, is the lower limit of the critical stress and that the heat shrinkage is preferably at one higher voltage than corresponds to the lower limit.

Such a peculiar contraction phenomenon appears only when an acrylonitrile mixed fiber is included Temperatures is treated which are above the secondary transition point of the fiber. When it comes to heat shrinkage tension is applied to the fiber in various ways. The simplest type is in letting the fiber hang freely and appropriately weighting it down. Will the mixed fiber shrunk in the manner already mentioned, then the crimp number is reduced more than when no weighting is applied, and if the tension is increased, none at all is formed Ripple. Here, however, the shrinkage of the mixed fiber becomes higher than that of the low-shrinkage Component, if you spin this component alone and post-treat it in the same way and then shrink from heat at the same temperature, but without tension. It is not a matter an apparent disappearance of the pucker as a result of the stretching caused by the weight, but under the microscope you can see that the components are parallel to each other and keep the same length. This is the evidence that the low shrinkage component is over-contracted. If the load (restriction) becomes too great, the fiber properties also deteriorate.

In general, the minimum weight necessary to avoid the development of puckering is required is greater with increasing heat shrinkage difference between the components in question. The minimum weight required is usually 0.2 to 5 mg / den, although the value is depending on the combination of the polymer components and the heat shrinkage conditions varies. The upper critical stress, i.e. H. the maximum weight that meets the condition, that the heat shrinkage of the mixed fiber is higher than that of the low-shrinkage component should be, is usually in the range of 3 to 10 mg / den, this value also from the Combination of the polymer components and the spinning and heat-shrinking conditions depends.

The medium in which the heat shrinkage according to the invention is carried out is not critical. Either dry or wet heat can be used. The 2nd order transition temperature of an acrylic fiber generally varies as a function of the type of polymer used and the previous history of the fiber in the stages preceding the heat drawing, but it can be influenced to a great extent by the medium used. The transition temperature is noticeably lower when a substance which has a plasticizing effect on acrylonitrile fibers is present, in particular water, acetonitrile, succinic acid dinitrile, dioxane, phenol, dimethylformamide or dimethylacetamide. According to the invention, therefore, the temperature range also varies depending on the medium used for the heat shrinkage. For example, when used as the medium of saturated steam, the temperature for the heat shrinking treatment above 105 ⁰ C, beimtrokkenen heating in air or nitrogen above 120 ⁰ C and in air containing water vapor or nitrogen, the temperature is above a mean value of these two temperatures. If we use a 10% aqueous phenol solution, or a 85.8% aqueous solution of acetonitrile, the temperature is above 70 ⁰ C. below said temperatures, the Uber contraction phenomenon will not appear the low-shrinkable component, even when varying the fiber tension. In order to sufficiently improve the composite fiber in terms of dyeability, knot strength, elongation and fibrillation resistance by heat shrinkage, it is desirable to shrink the fiber by 10 to 50%, preferably by 15 to 40%.

The application of tension to the fiber, on the other hand, can be done by such means that a After drawing the fiber, pack it in a container and place an appropriate weight on the fibers will. Becomes a mechanical crimped fiber of heat shrinkage after drawing a heavy weight will generally be required. In such a heat shrinking process the applied tension is variable depending on whether the fiber

curled or not depending on the shape of the container and the type of fiber packing. It also becomes the fiber also compressed by their own weight. The amount of tension placed on the fiber is therefore in the upper part of the container different from the one at the bottom of the container. Advantageously, the Tension applied uniformly to a previously mechanically crimped fiber regardless of its Location in the container.

There can also be continuous heat shrinkage of the fiber between two pairs of rollers, which have a different peripheral speed can be used. This is where the mixed fiber continuously shrunk in the heat, while the two roller pairs have such a low peripheral speed ratio (Bringing in / Bringing out) that the fiber shrinkage is identical to or less than that of a single component fiber, which only contains the low-shrinkage component of the mixed fiber and is in a tension-free state When it is heat-shrunk, it doesn’t naturally develop frizz, but the quality the fiber noticeably deteriorated. However, the peripheral speed ratio of the rollers becomes gradually increased and the mixed fiber introduced in such a way that the device is a little overloaded, measured by the shrinkage of the low-shrinkage component, the fiber is not only loosened, but surprisingly does not develop any curling. As already mentioned, this can be done by the Attributing overcontraction to the low shrinkage component. Becomes the roller peripheral speed ratio if it is further increased, the mixed fiber begins to develop curl, the curl number gradually increases, the fiber is loosened between the rollers, and the curl number becomes constant. Will therefore be better control the crimp development desired, one should consider the circumferential speed ratio of the rolls Select such that the crimp count is less than 80% of the crimp that is obtained when no tension is applied would have been generated.

The heat shrink treatment can also be applied to a bundle of threads that has been coated with an oil or the like is glued.

If the shrunk fiber becomes loose heat treatment with boiling water or steam is subjected, deep and superbly shaped crimps are occasionally obtained. These Appearance is of great practical importance, and the exploitation of such latent curling ability can produce yarns of excellent fullness. The ripple development through boiling Water or steam is effectively obtained when the heat shrinkage temperature is below 125 ° C with saturated water vapor and below 185 ° C with dry heat. However, it is Number of crimps less than 80% of the number of crimps obtained during the heat treatment in the tension-free Condition is achieved even if the crimp is achieved by treating a fiber with boiling Water or water vapor is developed or the number of which is increased, which has previously been heat-treated under stress had been. This can be attributed to the fact that the heat shrinkage difference is the Components has been downsized because of the overcontraction phenomenon. This does not change with the subsequent treatment with boiling water.

The aforesaid limited heat shrinkage usually increases the crimp reversibility of the composite fiber according to the invention. Will continue the limited heat shrinkage to other water reversible Blended fibers as described in British Patents 8,69,301 and 8,96,955 are used are, it is possible to increase the crimp reversibility of these fibers. The mentioned Fibers that have not developed curl after the limited heat shrink treatment can are also loosely exposed to boiling water treatment and then develop pleasing ripple.

The shrinkage of the low shrinkage component that has been described is the shrinkage the low-shrinkage polymer component as part of the mixed fiber when measured in this way is that this component is independently spun, drawn and under the same conditions as they prevail in the production of the mixed fiber, is post-treated and then the fiber obtained is heat-shrunk under completely the same conditions as the mixed fiber, with the exception that that they are not burdened.

When the fiber which has undergone the relaxation step as described and has been treated with boiling water to develop curl, is dried, further crimps occur due to the difference in the reversible change in length, excellent crimp is obtained.

The previous explanations mainly concerned the case of wet spinning, but it is superfluous mention that the dry spinning process can also be used. Even with dry spinning the fiber leaving the spinneret usually contains a solvent and must therefore be washed and washed be stretched. The behavior of the fiber in the stretching and shrinking stages is therefore basically the same as with wet spinning.

The fiber produced according to the invention has the following specific characteristics:

Reversible crimp fiber obtained by ordinary mix spinning is decreased the ripple number and, when subjected to tension, smooths the ripple in water itself below 70 ° C, which makes the product dimensions unstable during washing. In contrast to this develops the fiber produced according to the invention under tension in hot water at 70 ° C im has essentially the same curl number as in the dry state and only then shows a high one Crimp reversibility when treated in water at an elevated temperature above 80 ° C will. Furthermore, the fiber produced according to the present invention exhibits high curl developability, and the curl amplitude is large compared with a conventional fiber without curl reversibility. A knitted one or woven cloth made of the fiber according to the invention is excellent in bulk and has high curl developability and can be easily handled in processing. In addition, because of its large curl amplitude, this fiber gives a soft product with excellent Handle.

The fiber produced according to the invention can be mixed with wool, cotton, an ordinary mechanical crimped synthetic fiber or various types

of mixed fibers that have developed, or have not developed, curl or that have already developed The crimp has been removed again, can be spun together. The curling characteristic and the properties of the fiber used for mix-spinning are appropriately corresponding selected according to the intended use of the end product.

The solubility of the hydrophilic neutral monomer already described means the amount in Grams of solute per 100 g of water in a

aqueous, saturated monomer solution at 25 ⁰ C is included.

The water absorption of a polymer is measured as follows:

A polymer sample which passes through a sieve with a mesh size of 0.177 mm is left for 70 hours stand at 25 ° C and a relative humidity of 65%. The sample is then weighed (wet weight), dried at 110 ° C for 3 hours and ίο weighed again (dry weight). The water absorption is then

% Water absorption =

Wet weight - dry weight
Dry weight

100.

The shrinkage (HS) of a component of the mixed fiber according to the invention means the percentage of the shrinkage calculated from the fiber length before and after the stage in which the mixed fiber develops a substantial curl. Shrinkage is measured in the following ways:

The component to be measured is formed separately into the fiber under exactly the same conditions as for the production of the mixed fiber. The change in length of the fiber before and after the crimp development stage for the mixed fiber is calculated from the fiber length at 20 ° C. and 65% relative humidity and the value obtained is expressed as a percentage of the fiber length before this stage. The HS difference between the components is called AHS .

The reversible change in length (RLC) a component of the mixed fiber is the percentage of change in length of this component, even in air of 65% relative humidity (RH) at 2O ⁰ C and once measured in water at 80 ° C. The RLC value is measured as follows:

The component to be measured is independently processed into a fiber under the same conditions as in the preparation of the composite fiber, and then the fiber is subjected to a shrinking treatment under the same conditions as in the curl development treatment for the composite fiber. The fiber treated in this way is equilibrated in a room at 20 ° C. and 65% RH and the fiber length is measured under a load of 3 mg / d. The weighted fiber is placed in water at 80 ° C. and the fiber length is measured again after 6 hours. Again, the fiber is equilibrated at 20 ° C and 65% RH and its length is measured. This procedure is repeated until reproducibility of the results is achieved. The change in length in the dry state and wet state is expressed as a percentage of the length in the dry state.
The reversible curl change (A CFF) and curl reversibility (CRF) according to Test A of the invention is measured as follows:

A fiber sample with developed curl is attached at both ends to carrier plates so that the fiber is more or less relaxed. The fiber is immersed in water at 8O ⁰ C overnight (18 to 24 hours) and then the number of crimps counted. The fiber is then dried together with the carrier plates at 20 ° C. and 65% RH and the number of crimps is measured. The fiber is again placed in water at 80 ° C. and the number of crimps is determined. This procedure is repeated until reproducible results are obtained.

CRF (Vo) =

Pucker number, dry, at 20 ⁰ C - Pucker number in water of 80 ° C Pucker number (dry at 20 ° C)

100.

The Δ CFF value is the change in the number of crimps per 25 mm of fiber measured once in the dry state and once in hot water and is obtained by determining the length of the fiber sample from the previous measurement.

The reversible crimp change (A CFF) and crimp reversibility (CRF) according to Test B of the invention is determined in essentially the same manner as in Test A, except that the fiber is weighted at 3 mg / den in hot water of 70, 80 or 95 ° C will. On the other hand, there is no weighting when the fiber is dried. These measurements are made on the assumption that the fiber is subjected to tension during dyeing or washing.

The degree of swelling of the coagulated fiber during wet spinning is measured as follows:

A bundle of coagulated threads from a precipitation bath is placed on filter paper in order to quickly remove the adhering liquid and then weighed (wet weight). Thereupon the filament bundles at 110 ⁰ C is dried until a constant weight is reached, and then determining the dry weight. The degree of swelling is given by the formula

Wet weight

Degree of swelling (%) =

Dry weight

100

expressed.
The examples illustrate the invention.

example 1

There was a copolymer (A) with a specific viscosity of 0.17 with a content of 90% acrylonitrile (AN) and 10% N-vinylpyrrolidone (VPD). The polymer A has a Water absorption of 2.1%, while the homopolymer of VPD has such a rate of 21.8%.

A copolymer (B) with a specific viscosity of 0.17 was also prepared with a Content of 91.5% AN and 8.5% methyl acrylate (MA). The polymers A and B were separated in dimethylformamide (DMF) dissolved to 20% spinning solutions. Both solutions were made through a spinneret with 200 openings of 0.076 mm diameter in

509 636/323

a 50% aqueous dimethylformamide solution (DMF solution) pressed at 40 ° C, where they formed mixed threads with two arranged side by side Polymers in a ratio of 50:50.

The coagulated yarn was stretched to 4.5 times the original length during washing in boiling water and dried at 100 ⁰ C. After boiling in water, the thread had 22.5 crimps per 25 mm and a denier of 3.4. The curl reversibility in Test A (CRF) was 16.1% and the reversible curl change according to Test A (J CFF) was 3.6.

Each polymer A and B was then spun separately and drawn and dried under the above-mentioned conditions. The heat shrinkage difference (J HS) between the polymers A and B due to boiling water was 14.1%, the difference in the reversible length change (RLC) 0.4%. VPD can be mixed with water in any ratio.

Comparative experiment 1

For comparison, the procedure of Example 1 was repeated, with polymer A and polyacrylonitrile with a specific viscosity of 0.17 and a water absorption of 1.2% was used.

The mixed yarn produced had a denier of 3.1, a CRF of 5.2% and a Λ CFF of 1.8. The curl reversal was accordingly very weak in comparison with the thread of Example 1. The J HS value was 22.0%.

Example 2

A copolymer (C) with a specific viscosity of 0.17, consisting of 90% AN and 10% Acrylamide (AAm) was composed. The water absorption of the polymer C was 2.9%, that of a homopolymer (PAAm) of the hydrophilic, neutral monomer AAm, which is 120% is water soluble was 20.1%.

It must be noted that the water absorption of the polymer C is about that of a mixture of 90% PAN and 10% PAAm. If VPD is used, the water absorption of the copolymer becomes lower than that of the homopolymer mixture.

Polymer C and polymer B of Example 1 were separated into 20% strength spinning solutions in DMF solved. The spinning solutions were spun according to Example 1 into mixed threads.

The thread, after boiling in water, had 23.5 crimps per 25 mm and a denier of 2.9. According to Test A, the thread showed a crimp reversibility (CRF) of 34.0% and a change in the number of reversible crimps (ACFF) of 9.2. Of the . I HS value between polymer C and B was 8.9%, the polymer exhibiting higher shrinkage. The RLC value of polymer C was 4.2%. that of polymer B 1.5%, corresponding to a difference of 2.7%.

Remarkably, this thread shows a pronounced one high crimp reversibility compared to the thread according to example 1.

Comparative experiment 2

The process according to Example 2 was repeated, except that the PAN used for Comparative Experiment 1 was used Place of the polymer C was used. The thread so made had a denier of 2.7 and

a CRF value of 11.3%. The thread showed an extremely low crimp reversibility compared with the thread produced according to Example 2.

B e i s ρ i e 1 3

A copolymer (D) with a specific viscosity of 0.18 and a content of 87% AN, 2% vinyl acetate (VA) and 11% methacrylamide (MAAm). In addition, a

ίο Mixed polymer (E) produced with a specific viscosity of 0.17 and a content of 93% AN and 7% VA. The two polymers were separately dissolved in dimethylacetate (DMA) to spinning solutions having a viscosity of 500.Poise at 50 ⁰ C.

Both spinning solutions were spun together in a ratio of 50:50 using the spinneret described in Example 1. A 60% strength aqueous DMA solution at 50 ^° C. was used as the precipitation bath, the coagulated thread swelling by 340%. The coagulated thread was stretched 5 times during washing in boiling water and then dried at 135.degree. The water solubility of the hydrophilic neutral MAAm monomer is 28% and the water absorption of a homopolymer of these monomers is 22.3%. The polymer D has a water absorption of 2.9%. The dried thread was subjected to steam treatment at normal pressure and dried to develop curls. The thread thus treated had a denier of 4.8, showed 28.3 crimps per 25 mm, had a CRF value of 27.4% and a. 1 CFF value of 8.4.

The polymers D and E were individually formed into threads under the stated conditions and the RLC and HS values were measured. The RLC value difference between the two polymers was 1.9%, the J WS value 13.5%.

Example 4

A copolymer (F) with a specific viscosity of 0.16 and a content of 89% AN, 2% VA and 9% AAm produced. Under the conditions described in Example 3 were the polymers F and E from Example 3 spun together, drawn and dried. The dried ones Threads (C) were treated as follows:

a) The thread bundle was loosely shrunk by treatment with saturated steam at 129 ° C. The threads developed a large number of curls.

b) The thread bundle was placed on top of one another and the pile was subjected to ^{a pressure of 0.5 g / cm 2 by means of a weight.} The threads were then crimped with saturated steam at 129 ° C. The threads developed only moderate puckering.

c) The thread bundle was treated in the same way as in b), only the pressure was increased to 8 g / cm ² . ■

d) The thread bundle was suspended with a weight of 0.8 mg / den and by means of saturated Heat shrinkage of water vapor at 129 ° C. Ripples developed in far fewer numbers than in case a).

e) The treatment according to d) was repeated, but the weighting increased to 2 mg / d, more surprising was the heat shrinkage

of the mixed thread was not larger than that of polymer E, but rather none at all Ripple observed.

After the above-mentioned treatment, each sample was taken out in boiling water.

Table I.

and determines the crimp number, the CRF value and the fiber properties. Furthermore, each polymer was spun separately and aftertreated under the same conditions, and the RLC values and the Δ HS values were measured. The results are shown in Table 1.

treatment 22.0 untreated (G) RLC of the
Polymeri
sats F Curl number
per 25 mm CRF denier
(d) Tear length
(g / den) Elongation node
toughness
(g / den) a * Remarkably
mancrplnrlpr PJitypirräiiCf »' 2.9 58.4 12.1 3.41 2.35 47.5 2.10 b * 2.8 18.2 31.5 3.12 2.58 41.1 2.13 C. * - 17.8 33.4 3.21 2.60 40.3 2.10 d * - 23.5 28.3 3.18 2.48 43.5 2.15 e - 17.0 30.3 3.03 2.61 39.8 2.20 2.8 - - 2.25 3.25 20.3 1.68 ! developed
Ιιιησ if rtiiicpl f- Sample e) despite
tfM r \ f * r Rphsinrl- B e i s ρ iel 6

lung with boiling water. In the final treatment with boiling water, samples b), c), d) and e) developed considerable curling, although the shrinkage from boiling water at this stage is small and therefore the shrinkage difference between the individual components, i.e. the Δ HS value (* in Table 1) is extremely small (less than 1 to 2%).

B e i s ρ i e 1 5

The dry filament bundles G of Example 4 was loosely shrunk by treatment with saturated steam at 110 ⁰ C, to develop crimp, and thereby obtain a bundle K with 200 filaments of excellent dimensional accuracy similar to a dense yarn.

The thread bundle thus obtained developed 24.5 crimps on 25 mm and showed a CRF value of 32.5%. In Test B, it showed a Kräuselreversibilität (CRP) of 6.7% at 70 ⁰ C, 33.4% at 80 ⁰ C and 77.5% at 95 ⁰ C and a reversible Kräuseländerung of 2.1 or 5.3 or 9.7 at the temperatures mentioned.

Notably, the curl reversibility is lower at the low temperatures of test B. than that of the thread in the following comparative experiment.

Comparative experiment 3

A polymer with a specific viscosity of 0.17 and a content of 91% AN, 5% VA and 5% potassium vinylbenzenesulfonate (KVBS) was produced. This polymer was used together with polymer E from example 3 to produce a dry thread according to example 4. The dried thread was shrunk freely hanging with saturated steam at 120 ^{° C. for crimping.} The KVBS is a monomer that can be dissociated into ions. The resulting yarn showed 23.4 crimps to 25 mm and CRF values of 44.6% at 70 ° C, 47.0% at 80 ⁰ C and 76.3% at 95 ° C. Of the . I CFT value was 8.8, 8.9 and 9.6 at the temperatures mentioned. The C / IF value of the thread was 33.0%.

To 100 parts of an aqueous emulsion of a polymer having a specific viscosity of 0.25 and a content of 55% AN and 45% VA (polymer content 32%) were 12 parts of methanol and Added 2.0 parts of sulfuric acid. The mixture was heated to reflux and stirred for about 30 minutes. The mixture was then distilled off, with 600 parts of water continuously over a period of 6 hours were fed. In this case, the rate of distillation was the same as the rate the water supply.

After complete hydrolysis, the polymer obtained was washed with methanol and dried. Before and after the hydrolysis, the polymer was subjected to an infrared analysis, the weak acidic groups (carboxyl groups) were estimated. It was found that about 65% of the VA im Polymer were hydrolyzed, while the nitrile group was not hydrolyzed. The polymer was dissolved in DMF at a concentration of 13% to form a spinning solution. Separated from this was a polymer with a specific viscosity of 0.25 and a content of 90% AN and 10% VA in DMF dissolved to a spinning solution with a concentration of 16%. Both spinning solutions were in proportion Pressed 50:50 through the spinneret described in Example 1 in order to obtain a mixed fiber. That The precipitation bath consisted of a 30% strength aqueous DMF solution. The coagulated thread was during the Laundry stretched twice in water at 45 ° C and then dried. The drawn thread was then relaxed in water at 50 ° C and dried, as a result of which 25.8 ripples developed on 25 mm became. The CRF of the thread was 16.8%.

In addition, the water absorption of polyvinyl alcohol was determined to be 7.01%.

In this example, the water temperature was for the CRF value measurement 50 ⁰ C.

B e i s ρ i e I 7

Various polymers were dissolved in DMF to form spinning solutions. According to example 3

The methods described were different combinations of the spinning solutions together in aqueous Spun DMF solutions so that the polymer ratio was 50:50. The coagulated thread was each washed with water, stretched and over

Table II

dried a constant length at a temperature of 50 to 135 ° C. Samples thus obtained were thermally shrunk to crimp under various conditions. In Table 2, the Properties of the threads obtained are listed.

Polymer combination the end more hydrophobic AN-EMA Conditions of heat AHS Ripple CRF other cases at 135 ° C. RLC- Component B (97-3) shrinkage (tension-free) pay on difference more hydrophilic AN-VA AN — MA ** 25 mm Component A (91-9) * (85-15) (AWAY) (AWAY) AN — VA — AAm AN-VA AN — MA — ST *** 12O ⁰ C 4.5 17.2 35.6 1.5 (89-2-9) + 2 parts AN — VA ** (98—7) (82-15-3) saturated water vapor 1 part AN-AAM (70-30 + 93-7) 12O ⁰ C 15.1 23.4 28.0 1.5 AN-AAm saturated water vapor (95-5) AN-AAm 145 ° C 3.5 12.1 29.2 0.8 (80-20) saturated water vapor AN-AAm Steaming under 19.5 45.0 20.4 2.8 (70-30) Normal pressure Remarks: Hot water at 80 ° C 15.5 27.6 50.2 4.2 * That in brackets Mixing ratio in the polymer. ** The + sign means a mixture; the water absorption of the AN (70) -AAm (30) copolymer is 4.8%. EMA means ethyl methacrylate, ST means styrene. *** The drying temperature was 50 ° C; in the

Example 8

A mixed fiber obtained according to example 3 of the combination of polymer E and F according to example 4 was obtained under the following conditions:

a) Dimethyl sulfoxide (DMSO) was used as the solvent and the polymer solutions in a 55% aqueous DMSO solution is spun in at 40.degree. The degree of swelling of the coagulated Fiber was 300%, the resulting thread had a denier of 5 and a CRF value of 26.5%.

b) The solvent used was a 55% strength aqueous NaSCN solution and 11% strength polymer solutions which were pressed into an 8% aqueous HaSCN solution at 20 ° C. Of the The degree of swelling of the coagulated thread was 640%, and the denier of the thread obtained was 5 and its CRF value 30.5%.

c) A mixture of 90% polyethylene glycol (molecular weight 600) and 10% DMA used and spun at 100 ° C. The degree of swelling of the coagulated thread was 190%, the denier of the obtained thread5 and its CRF value 19.8%.

The polymer F alone showed RLC values under the same conditions of a) 2.71, b) 3.86 and c) 2.40.

Example 9

The polymer C of Example 2 and a copolymer (J) with a specific viscosity of 0.16 and a content of 91% AN and 9% VA were dissolved in DMA to form 30% solutions so that the spinning solutions were essentially the same Exhibited viscosity. Both spinning solutions were pressed through a spinneret with 60 openings, each 0.08 mm in diameter, into countercurrent air, a mixed thread arranged side by side being formed. The temperature of the spinneret and the spinning solution was 105 ⁰ C. The spin column of 5 m length was maintained at the top to 180 ° C and at the bottom to 200 ⁰ C. At the bottom of the column, the resulting threads were peeled off at a speed of 150 m / min and washed in boiling water while being drawn under an appropriate tension. The threads were then further drawn under dry heat from 160 ° C. to a total of 7 times. The threads were treated with steam and then dried. One thread was 4.8 denier. The curl count was 18.5 by 25 mm and the CRF value was 20.3%.

B e i s ρ i e 1 10

The polymers E and F described in Example 4 were dissolved in DMA so that the Solutions had a viscosity of 600 poise at 50 ° C. Both spinning solutions were in proportion 50:50 fed to a distributor plate with ten holes in such a way that the one dope at the top Surface entered and exited on the lower surface of the distribution plate, while the other dope laterally entered the distributor plate in a space disposed between the upper and lower surfaces. The streams of the first spinning solution were thereby surrounded by the second spinning solution without each other the two spinning solutions mixed. The spinning solution flow flowing off the lower surface of the distributor plate was accordingly composed of ten jacketed streams. The spinning solutions were then into a spinneret with 200 openings from

in each case 0.076 mm in diameter and, according to Example 3, in a precipitation bath of aqueous DMA solution pressed. Two spinning solutions arranged side by side were passed through part of the spinneret openings extruded, while only one solution emerged through the remaining openings. That coagulated thread bundles were drawn 5 times in boiling water washing and then dried at 135 ° C.

62% of the fibers of the dry fiber bundle were threads of the individual polymer component E or F. The thread bundle (H) is thermally shrunk by means of steam at 110 ⁰ C, which, surprisingly, not only the mixing threads, but all the strings, including the from the individual components E or F Developed ripple. The filaments were about 3 denier and the crimp count was 21.7 over 25 mm. The obtained crimped thread bundle (I) had an excellent hand and a large bulk.

The mixture of mixed and single component threads thus obtained had excellent dimensional stability when dry and when wet and resulted in special grip effects for comparison with thread bundles made only from mixed threads.

For example, the elongation in the dry state with a weight of 50 mg / den in bundle I and in bundle K of Example 5 without individual component thread (initial weight 5 mg / den) was 7.3 and 13.3%, respectively. At a weighting of 10 mg / den in water at 80 ° C (Anfangsbeschwerung 1 mg / den in water at 80 ⁰ C), however, the elongation was 4.7% I of the bundle which the bundle K 9.0%. This results in a far better dimensional stability and fullness of the bundle I.

Example 11

a) The thread bundle H produced according to Example 10 was by means of saturated steam at 129 ° C thermally shrunk, with all threads developing crimps with a crimp number of 38.5 to 25 mm.

b) The thread bundle H was put together and a weight was attached to the bundle, thereby exerting a pressure of 8 g / cm ² . In this state, the threads were thermally shrunk with steam at 129 ° C - all threads developed crimps in a number from 23.7 to 25 mm.

Example 12

Mixed threads were produced by means of the distributor plate used in Example 10. With an opening number (N) 20 of the distributor plate, ie with a ratio

η (number of spinneret orifices)
N (number of distributor plate openings)

= 10

the ratio of the mixed threads was 83%, when N = 4, that is, n / N = 50, the ratio was 36%. In this case, the mixing ratio can be determined from the ratio N to η .

Example 13

The bundle of coagulated filaments, which had been produced according to Example 10, was drawn twice instead of 5 times and then dried at 135 ° C. The bundle was then further drawn 4 times while being heated by means of hot air in a tube so that the filament bundles temperature to 160 ⁰ C increased. the bundle was then shrunk with saturated steam at 105 ⁰ C, wherein all the threads of the bundle crimps developed in a number from 23.5 to 25 mm. the tenacity was 3.82 g / d and was higher than in the case of Example 10, where the value was 2.73 g / den.

Example 14

The two spinning solutions used in Example 10 were in the ratio 50:50 openings of a spinneret with 7000 of 0.08 mm in diameter fed, and spun into a coagulation bath of 30 ⁰ C in 60% DMA and 40% water, so that all threads in the ratio 50 : 50 were arranged side by side. The obtained thread bundle was drawn 6 times in boiling water, washed and dried. The dry thread bundle was placed in a container, subjected to a pressure of at least 5 g / cm ² in a steam chamber and then thermally shrunk with saturated steam at 129 ° C. in the usual way. The bundle was then subjected to a steam treatment at normal pressure under tension, mechanically crimped and cut.

The staple fiber obtained showed no significant self-curling, but mechanical curling between 12 and 15 by 25 mm. The staple fiber was made into a 2/36 two-ply yarn in a known manner about 3.54S and about 2.36 Z twists spun. The yarn was steamed and dried to give a decidedly pleasing, full yarn with excellent grip.

A combination of polymer J from Example 9 and polymer E from Example 3 was subjected to the same process steps in another experiment and a spun yarn made from mixed fibers without water reversibility (CRF value = 3.5%) was obtained. Compared with this yarn, the fiber produced in accordance with the present invention was superior in shape, and it was soft and excellent in hand. In addition, a yarn made from the fiber obtained according to the invention showed less stretching, especially in hot water, and showed far better stability than a conventional fiber provided with reversible crimping and containing a group that can be dissociated into ions, ie the fiber of Comparative Experiment 3.

Example 15

The two spinning solutions from Example 14 became threads under the conditions described in Example 11 processed with the difference that the spinning solutions over a distributor plate with 500 openings distributed in dope flows with 500 jacketed streams and the flows in a spinneret with 10000 openings of 0.08 mm diameter were given.

Of the total threads 65% were mixed threads, 21% single component threads made of polymer F and 14% individual component threads made from polymer E. The spun yarn obtained was steamed and closed a yarn with greater bulk (yarn diameter) and softness than that produced according to Example 14 Yarn.

509 636/323

The yarn obtained is easy to handle because it is dry and wet despite the higher Fullness is less stretched and the fullness develops evenly under drying conditions shows.

In addition, the yarn threads shift with repeated drying and moistening treatments, so that a yarn is obtained which is extremely excellent in feel and appearance.

Example 16

A copolymer (L) with a specific viscosity of 0.17 and a content of 92% AN and 8% MA and a copolymer (M) with a specific viscosity of 0.17 with a content of 86% AN and 14% AAM were each dissolved in DMA to make 22% solutions.

The two spinning solutions were pressed through a spinneret with 50 openings.

The spinneret was located above the liquid surface of the precipitation bath, as a result of which the squeezed spinning solution flowed about 1 cm through the air and then entered and coagulated vertically in the surface of the precipitation bath made of DMA and water. The thread bundle was removed from the precipitation bath and stretched while washing in boiling water for 2 times, dried and hot stretched by 3 times under such conditions that the temperature was 160 ⁰ C bundle. Subsequently, the bundle was exposed between rolls dry heat, to increase the bundle temperature to 180 ⁰ C, and then continuously thermally shrunk. In this operation, the speed ratio of the rollers before and after the heat-shrinking treatment was appropriately selected so that the bundle shrank by 28% with no curl formed after the heat-shrinkage. The denier of the fiber was 3. The thread bundle developed crimp after steam treatment and subsequent drying, whereby a crimped yarn with excellent feel and appearance was obtained. For comparison, the same procedures were repeated except that the heat shrink treatment consisted dry heat of 18O ⁰ C in the stress-free state, with 85 crimps developed mm on 25th Even when the fiber was subjected to boiling water and drying treatments, the curl number did not change.

in which R ₃ , R ₄ and / or R _{5 are} hydrogen or a lower alkyl group or R ₄ and R ₅ are connected to one another to form a five- or six-membered ring, is polymerized.

4. Process according to claims 1 to 3, characterized in that one in the other Spinning solution used a copolymer containing 80 to 96 percent by weight of acrylonitrile units.

5. Process according to claims 1 to 4, characterized in that the stretched Subjecting fiber to a shrink treatment for curl development in a hot medium stretched to remove crimp, spun into a yarn and then another Subjected to shrink treatment for curl development.

6. The method according to claims 1 to 4, there-

characterized in that the drawn fiber is subjected to a heat treatment at a temperature below 100 ^° C. in a relaxed state, spun into a yarn and then subjected to a shrinking treatment to develop crimps.

7. Process according to claims 1 to 4, characterized in that the drawn The fiber undergoes heat shrink treatment at a temperature higher than the second transition temperature Fiber subjects under such a tension that the crimp number due to the shrinkage difference between the polymer components is less than 80% of the crimp number, which is fully developed in the tension-free state, and that the shrinkage of the mixed fiber is greater than that of the less shrinking polymer component.

Claims (2)

Patent claims: 1. Process for the production of multicomponent threads or fibers from acrylonitrile copolymers by simultaneous spinning of at least two spinning solutions that are different Acrylonitrile polymers contain, in a precipitation medium, stretching and shrink treatment of the obtained threads and, if necessary, repeated shrink treatment of the fibers or threads in the form of yarns, knitted fabrics or woven fabrics made from them, characterized in that, that one of the spinning solutions is the solution of a hydrophobic, 80 to 96 percent by weight Acrylonitrile-containing copolymer without a hydrophilic neutral comonomer and as a second spinning solution, the solution of a hydrophilic acrylonitrile copolymer with a polymerized proportion of 5 to 30 percent by weight of a hydrophilic neutral Monomers used. 2. The method according to claim 1, characterized in that there is an acrylonitrile copolymer used, in which a compound of the general formula as the hydrophilic neutral monomer