KR810001271B1 - Hygroscopic fibers and filaments of synthetic polymers - Google Patents

Abstract

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Description

Method for preparing absorbent fibers and filaments of synthetic polymers

1 is a cross-sectional view (320 times magnification) of a sliver taken with an optical microscope according to Example 1 of the present invention.

2 is a longitudinal cross-sectional view (320 times magnification) of a fiber taken with an optical microscope according to Example 1 of the present invention.

The present invention relates to a process for producing hygroscopic fibers and filaments of synthetic polymers.

In many textile applications (e.g. bed linen or underwear), it is desirable to use synthetic fibers that exhibit properties similar to the moisture of natural fibers, such as cotton, from the viewpoint of moisture in synthetic fibers. . Therefore, many attempts have been made to improve the properties of synthetic fibers, which are not good in this respect, but in the past, they have never removed any drawbacks.

For example, hygroscopic natural fibers have been blended with synthetic fibers. That is, it is known that polyacrylonitrile can be mixed with other acrylonitrile polymers containing from 30 to 80% by weight of polyethylene oxide methacrylate, thus spinning the resulting mixture (German patent specification) No. 1645532).

It has long been known that acrylic fibers containing polyethylene oxide chemically bonded to ethoxylated acrylic acid derivatives are effective in their antistatic properties even if their moisture content is not particularly high. Many such attempts have also been made to copolymerize certain monomers to enhance the hygroscopic quality. For example, according to Japanese Patent Application No. 2782/70, monomers containing hydrophilic groups (e.g., acrylic acid derivatives) have been compounded to the polymer and then hydrolyzed, and in particular, German Publication No. 2081213 has acrylamide substituted with comonoma. Presented. Many such attempts have also been made to improve the quality of absorbency by crosslinking. German Publication No. 2,303,893 describes hydrolysis of wet spinning expanded acrylic fibers containing N-methol compounds of unsubstituted amides in copolymerized form with sulfuric acid. It was also possible to crosslink by US Pat. No. 3,733,386, which treats fibers with aldehyde compounds and acids to obtain fibers having enhanced water absorption.

However, despite many proposed methods, it has not been possible to date to produce synthetic fibers having hygroscopic qualities close to good hygroscopicity. Cotton has 65% relative humidity, 21% moisture content, and 45% water retention.

Accordingly, it is an object of the present invention to provide synthetic filaments and fibers having enhanced moisture content. Moreover, another object of the present invention is to provide synthetic filaments and fibers having enhanced water retention. In particular, another object of the present invention is to provide synthetic filaments and fibers having improved moisture content and water retention compared to conventional synthetic fibers and filaments.

It is a preferred object of the present invention to provide acrylonitrile filaments and fibers having enhanced moisture content and water retention compared to conventional acrylonitrile filaments and fibers.

Accordingly, an object of the present invention is to provide a method for producing such fibers and filaments.

It was surprisingly found that the enhancement method required above was obtained by dry spinning when a liquid having special properties was added to the solvent for the polymer.

Thus, the present invention has a higher boiling point than the spinning solvent used and is easily blended with both the spinning solvent and water and exhibits 5 to 50% by weight of the solution, which represents a nonsolvent in the spun polymer (based on solvents and solids). ) Is added to a spinning solvent, and a method for producing hygroscopic filaments and fibers having a core (pi) structure by dry spinning from a filament-forming acrylonitrile polymer.

By the method of the present invention it was possible to obtain a filament and fiber of a core structure having a moisture content of at least 2% (at 65% relative humidity and 21 ° C.) or more and at least 10% or more water retention.

The invention also relates to their filaments and fibers. Polymeric acrylonitrile polymers used to make the filaments and fibers are preferred and at least 50% or more preferably composed of acrylonitrile units and very preferably at least 85% by weight or more acrylonitrile polymer. In the case of using acrylonitrile polymers, the hygroscopic quality of the fibers may be further enhanced by using copolymers containing comonoma and hydrophilic amino, sulfo, hydroxyl-N-methylol or carboxyl groups. Particularly suitable compounds are, for example, N-methylol compounds of acrylic acid, methacrylic acid, methalyl sulfonic acid, acrylamides and unsubstituted acid amides such as N-methylol and N-methylol methacrylamide. Mixtures of polymers may also be used.

Suitable spinning solvents are those solvents commonly used for dry spinning, for example dimethyl acetamide, dimethyl sulfoxide, N-methyl pyrrolidone but preferably dimethyl formamide.

The solution added to the spinning solvent must meet the following necessity. That is, the boiling point of these liquids should be higher than the boiling point of the solvent, preferably 50 ° C. or higher, and must be compatible with any solvent and water or in any ratio with another liquid used as a cleaning agent, and also the polymer used in the actual phase. It must be non-solvent for, ie in other words, the polymer should only dissolve in this solution within a very limited range.

Liquids that meet the above mentioned needs include, for example, mono- and poly-substituted alkyl ethers and esters of polyhydric alcohols such as diethylene glycol mono-or-dimethyl, -ethyl and -butyl ether, Diethylene glycol, triethylene glycol, tripropylene glycol, triethylene glycol diacetate, tetraethylene glycol, tetraethylene glycol dimethyl ether, glycol ether acetates such as butyl glycol acetate. It is also possible to use high boiling alcohols (eg 2-ethylcyclohexanol), esters or ketones or mixtures (eg mixtures of ethylene glycol istates).

Glycerol and tetraethylene glycol are preferably used.

It is also possible to use a mixture of liquids to add one liquor, but it is extremely important that the liquid used be easily dissolved in water in order to be able to be removed again after treating the fibers.

It is also advantageous to use liquids which do not form an azeotrope with the spinning solvent used in order to be able to be almost completely regenerated by fractional distillation in the case of DMF-glycerol or DMF-diethylene glycol mixtures.

They are added dropwise to the spinning solvent in an amount of 5 to 50% by weight, preferably 10 to 20% by weight, based on the total solvent and solids.

The upper limit of the miscible liquid (phase) is actually determined by the radioactivity of the polymer solution.The maximum amount of the weight of the liquid is determined from the spinning solvent, the maximum porosity in the core of the fiber, and from such spinning solution water. It is added dropwise to the quality of the maximum hydrophilicity of the filament produced.

In the case of glycol, it is possible to add a polyacrylonitrile solution of 16% by weight to 17% by weight in DMG. In order to obtain a complete mixing of the spinning solution, it is preferable to first mix the spinning solvent, for example DMF, with a relatively high boiling point solution and then add the polymer powder dropwise to the energetically stirred solution because of the polyacrylic in the DMF. This is because the direct addition of glycerol to the ronitrile solution can cause precipitation.

In order to obtain fibers with a high hygroscopic quality as high as possible by the method according to the invention, the spinning treatment is chosen to evaporate together by means of a spinning solvent which evaporates as small as possible or evaporates as little as possible in the spin tube during the shoulder spinning process. do. The short residence time in the radiation tube proves to be of significant benefit due to the extreme low radiation tube temperature, short radiation tube and high radiation ratio which are only above the boiling point of the evaporating spinning solvent. For this reason the temperature of the radiating tube should be at a maximum of 80 ° C., preferably 5 to 30 ° above the boiling point temperature of the spinning solvent used.

As a result of these measurements, most of the added liquid (typically 90%) remains in the sliver or filament. This is removed by a short cleaning in the process after the treatment.

The hygroscopic quality of the fibers with the resulting core structure can thus be further cured by the special form after treatment and the method performed. For example, if the acrylic fibers of the DME-glycerol mixture are stretched to steam or water by the spinning method according to the present invention and then subsequently washed, dried and treated, the first dense skin surface of the fibers or filaments may be highly dispersed through glycerol diffusion. Even if the microcaliber is obtained, acrylic fibers having a particularly high absorptive quality are thus obtained.

In spinning the polymer from the DMF-glycerol mixture in an amount of 17% by weight of polyacrylonitrile solids and 15.7% by weight of glycerine, the filaments spun by the method described above are first treated and then adapted to suitably match the hygroscopic quality of cotton. It is possible to obtain acrylic fibers having the same amount of water retention of 30% or more and 5% moisture content. However, when the core fibers are first washed and then stretched, the dense structure is completely cleaned before the glycerol is stretched and the vacuoles formed by glycerol diffusion are closed again by the stretching method. Due to the acrylic fibers having a dense surface, a low hygroscopic quality is thus obtained (cf. Example 2).

The washing of the seam-fiber may be performed at a temperature of 100 ° C. or lower. The residence time should be at least 10 seconds to thoroughly wash the added liquid.

In carrying out the cleaning, it is also advantageously demonstrated to keep the slivers or filaments only under weak tension or to shrink them to an extremely limited range in order to maximize the removal of the added liquid.

Continuous post-treatment of the slivers or filaments may be carried out with conventionally used post-treatment techniques such as preparation, winding, drying and cutting under the condition of drying the fibers in order to make the hygroscopic quality of the fibers more effective.

160 ° C., preferably at 110 to 140 ° C., a very suitable drying condition and a short residence time of 2 to 3 minutes in the dryer give a carpel structure with extremely good hygroscopic quality.

An increase in the water content and water retention of the cardiofibers according to the present invention in relation to the cleaning stretching method is such that fibers or filaments containing only a very small amount of spinning solvent leaving the tube are immediately drawn, polished, dried and known methods (cf. It may also be obtained when it is post-treated to form a fiber in Example 3). As mentioned above, the filaments and fibers according to the present invention have a sheath structure. In these cortical structures, the seam is microscopic, with an average diameter of about 1μ and generally between about 0.5 and 1μ. The surface area of the seam in the cross section through the fiber is almost 70% of the total cross section.

The blood may be dense or even microscopic, depending on the state of treatment, especially after it has been established. While the cross section of conventional dry spun filaments and fibers is known dumb-bell or bone form, the filaments and fibers according to the present invention mainly have different cross sectional shapes. Thus, it leads to a structure of irregular shape, triro foot shape, mushroom shape, and round bean shape, which are parallel to each other in any case. The excellent cross-sectional shape is dependent not only by the special spinning state established but also by the amount of liquid added to the spinning solvent, where the latter measurement has a greater influence.

In addition to the hygroscopic qualities described above, the filaments and fibers according to the present invention exhibit excellent fibrous properties such as high tensile strength, elongation at break and good dyeability.

Another extremely significant advantage of the fibers according to the invention in wearing arises from the cortical structure of these fibers. Naturally, the same natural fiber has a high wettability with high water absorption, which is not the case of the fiber according to the present invention. This is evidenced by the fact that the absorbed water diffuses into the microbore. As a result of this, the fibers of the present invention are completely non-wetting and actually provide comfort.

Thus, although this technique has a significant distance between acrylic fibers and their production, the present invention is not limited to the production of acrylic fibers. Linear, aromatic polyamides such as polyamides of m-phenylene diamine isophthalyl chloride, or those in the form of optionally having a heterocyclic system, for example polybenz imidazoles, oxazoles, thiazoles and dry spinning Forms that can be made may also be used in the present invention.

Other suitable compounds are generally polymers having a melting point of at least 300 ° C. which can no longer be spun from the melt and can be prepared by solution spinning, for example dry spinning.

The water retention of the fibers is an extremely important vehicle for their use. The effect of high water retention is that they can maintain a relatively dry skin as a result of a lot of sweat when the fibers are worn again and are convenient to wear by them.

Measurement of water holding power (WR)

Water retention is measured according to DIN 53814 (see Melliand Textilberichte 4, 1973, page 350). The fiber sample is immersed in water containing 0.1% wetting agent for 2 hours, then the fiber is centrifuged for 10 minutes at an acceleration of 10,000 m / sec ² and the amount of water remaining in and between the fibers is determined by gravimetric analysis. To measure the dryness of the fibers, the fibers are dried at 105 ° C. so that they have a constant moisture content. Water retention force (WR) in weight% is represented by following Formula.

m _f = weight of moisture fiber

m _f = weight of dry fiber

Moisture Content (MR) Measurement

Moisture content of the fibers is determined by gravimetric analysis based on their dry weight. Finally, the sample is exposed at 21 ° C./65% relative humidity for 24 hours and dried at 105 ° C. to determine the dry weight of the sample to make the weight constant. The moisture content (MR) by weight is represented by the following structural formula.

m _f = 21 ° C / 65% relative moisture weight of the fiber

m _f = dry weight of the fiber

The invention is further illustrated by the following examples in which the parts and percentages are by weight unless otherwise indicated.

Example 1

18.9 kg of DMF was mixed with 4.8 kg of glycerol in a container, followed by dropwise addition of 5.1 kg of acrylonitrile copolymer of 93.6% acrylonitrile, 5.7% methyl acrylate and 0.7% sodium metalyl sulfonate dropwise with stirring. The mixture was stirred for 1 hour at 80 ° C., filtered, and the spinning solution was dry spun from a spinneret of 180 holes in the spinneret by a known method. The temperature of the spin tube is 160 ° C., and the viscosity of the spin solution having a solids concentration of 17 wt% and a glycerol weight 15.7 of 15.7 wt% is calculated as 85 ball drop based on DMF ⁺ polymer powder. Viscosity measurements by ball drop are described in the literature. See K. Jost, Rheologics Acta, Vol. lo. 2-3 (1958), page 303]. The emissive material with denier of 1700 dtex is concentrated in the bobbin and then overlapped with a sliver with a total denier of 102,000 dtex. After leaving the tube, the sliver contained 14.1% by weight glycerol.

The glycerol content of the sliver is measured by gas chromatography analysis and the tow is elongated in boiling water at a ratio of 1: 3.6 and then washed in boiling water under mild tension for 3 minutes to provide antistatic properties. This is done by drying the screen in a screen drum dryer at a maximum temperature of 130 ° C. allowing the bullfight to be cut into fibers having a staple length of 60 mm and then allowing 20% shrinkage. Individual fibers with a final denier of 3.3 dtex had a moisture content of 5.2%, a water retention of 32.8%, a tensile strength of 2.6 p / dtex, and an elongation at break of 41%.

After leaving the radiation tube, the fibers have an irregularly compounded seam-blood structure (typically in Trilobal cross-sectional form) as shown by the photograph taken with an optical microscope of cross section in FIG. 1 (320 times magnification). The surface of the blood has a useful width of almost 4 μm, and in order to measure the sheath and skin of the fiber, more than 100 fiber cross sections are quantitatively evaluated by a Leitz® Classimat® image analyzer. An average of 32% of the cross-sectional area has a useful width. FIG. 2 is a photograph taken with an optical microscope of three filaments (320 times magnification), and in this case, the carpel structure having a denser blood and a clear hole core can be clearly seen. The residual glycerol content is 0.6% by weight while the residual solvent content of the fibers is 0.2% by weight or less. The fibers can be deeply dyed with blue dyes corresponding to the following structural formulas.

The distinguishing value is 1.39 for 100 mg of fiber per 100 ml of DMF (570 mμ, 1 cm Cuvette). Yarns with a 36/1 water frequency are spun from fibers with a final denier of 3.3 dtex and are also made of knitted fabrics, some of which are white on one side and dyed blue on the other, with a moisture content of 5.1% and water retention of 34.3%. to be.

Example 2

The acrylonitrile copolymer having the same chemical composition used in Example 1 was dissolved in the DMF-glycerol mixture under the same conditions, then filtered and spun to concentrate this spinning in bobbin and into a sliver having a total denier of 102,00 dtex. Duplicate The material is rinsed in boiling water under tension for 3 minutes, stretched at a ratio of 1: 3.6 and then subjected to antistatic treatment and worked up in the same manner as described in Example 1. Individual denier fibers of 3.3 dtex have a water content of 2.0% and a water retention of 11.4%. This fiber has a clear seam-blood structure and irregularities, usually a trilobal cross section.

Compared with the fiber of Example 1, the surface to be treated is more dense and not penetrated by the axe. This is explained by the low hygroscopic quality of the fibers as compared to Example 1. Due to the modified aftertreatment process, the vacuoles formed through the removal of glycerol during cleaning are again largely closed by the stretching process performed after cleaning.

Example 3

Acryltonitrile copolymers having the same chemical composition used in Example 1 are dry spun from the DMF-glycerol mixture under the same conditions. Directly stretch the sliver with 102,000dtex denier in boiling water at a ratio of 1: 3.6, dry it at 120 ° C with a screen drum dryer that allows formulation, crimping and shrinkage of 20%. Made of waffle fiber A fiber with a final denier of 3.3 dtex has a water content of 2.9% and a water retention of 24.5%. The fiber cross section is thus a shim-blood structure with a trilobal cross section.

Example 4

10.0 kg of DMF was mixed with 2.15 kg of glycerol in a container, followed by dropwise addition of 2.85 kg of acrylonitrile copolymer of 91.1% acrylonitrile, 5.5% methyl acrylate and 3.4% sodium methacrylate sulfonate with stirring. Stir at 80 ° C. for 1 hour, filter, and spin the processed spinning solution in the same manner as described in Example 1. The spinning solution with a solids concentration of 19% -glycerol content of 14.5% based on DMF and PAN replacements has a viscosity of 78 voldrops. Emissions with denier of 1710 dtex were overlapped with tow and worked up in the same manner as described in Example 1. Individual fibers with a final denier of 3.3 dtex had a water content of 5.8% and a water retention of 35.3%. The fibers are therefore irregular trilobal cross sections and exhibit a clear seam-blood structure. The enhancement of hygroscopicity in connection with Example 1 is illustrated by the increased presence of acid groups in the copolymer.

Example 5

10.4 kg of DMF was mixed with 2.15 kg of glycerol in a vessel while stirring, and then 2.85 kg of acrylonitrile copolymer of 90% acrylonitrile, 5% acrylamide and 5% N-methoxy methylacrylic was added while stirring The spinning solution formed by stirring and filtering the mixture at 80 ° C. for 1 hour is spun in the same manner as described in Example 1. Based on the DMF and PAN solids, a spinning solution having a solids content of 15% and a glycerol content of 14.5% has a viscosity of 69 ball drops. Emissions with denier of 1700 dtex were duplicated again with tow and then worked up in the same manner as described in Example 1. Fibers with a final denier of 3.2 dtex had a water content of 5.3% and a water retention of 34.9%. The fibers are thus trilobal cross sections, which are irregular, generally clear seam-blood structures. The improved hygroscopicity compared to Example 1 is illustrated by the presence of hydrophilic amino and N-methoxymethyl acrylamide groups in the copolymer.

Example 6

6.1 kg of DMF1 was mixed in a vessel with stirring with glycerol 3.4, followed by 2.0 kg of acrylonitrile copolymer of acrylonitrile 91.1%, methyl acrylate 5.5% and sodium methylyl sulfonate 3.4 and 90% acrylonitrile 5% acrylamide And 2.0 kg of N-methoxymethyl acrylamide 5% acrylonitrile copolymer- dropwise with stirring. After spinning and filtering for 1 hour at 80 ° C., the spinning solution was spun in the same manner as described in Example 1 to continuously work up this spinning material. The glycerol content is 14.5% by weight based on the DMF-PAN mixture. A spinning solution with 17% solids by weight has a viscosity of 68 ball drops. A fiber with a final denier of 3.3 dtex has a water content of 5.7% and a water retention of 31%. Thus, these fibers are usually clear seam-like structures with a cross-sectional toe.

Example 7

8.6 kg of DMF was added dropwise with 2.17 kg of glycerol to the vessel, followed by dropwise addition of 4.2 kg of acrylonitrile copolymer of 59% of acrylonitrile, 37.5% of vinylidene chloride and 3.5% of sodium metharylsulfonate. After stirring at 50 ° C. for 1 hour, the filtered solution containing 14.5% by weight of glycerol based on DMF and PAN solids was dry spun and worked up in the same manner as described in Example 1. The spinning solution has a viscosity of 53 ball drops and a fiber having a final denier of 3.3 dtex has a distinctly seam-like structure and pore core with a uniquely rounded cross section, a water content of 2.0% and a water retention of 38%.

Example 8

16.5 kg of DMF were mixed with 3.5 kg of diethylene glycol in a vessel while stirring, followed by dropwise addition of 6.0 kg of acrylonitrile having the same chemical composition as used in Example 1, followed by stirring as described in Example 1. Dry spinning results in post-treatment to form fibers. Spinning solutions containing 13.5% by weight of diethylene glycol based on DMF and PAN solids had a viscosity of 65 ball drops. Fibers with a final denier of 3.3 dtex exhibit an apparent seam-blood structure with a triro-cross section, with a moisture content of 4.3% and water retention of 27.4%.

Example 9 (Control)

a) 13.1 kg of DMF is mixed with 4.9 kg of ethylene carbonate in the container with stirring, and then 6.0 kg of acrylonitrile copolymer having the chemical composition as used in Example 1 is added dropwise with stirring.

The ethylene carbonate content based on the DMF and PAN mixture is 20.5% by weight for a solids concentration of 25% by weight. After stirring for 1 hour at 80 ° C., the solution is filtered, dry spun and the spun material is worked up in the same manner as described in Example 1 to form fibers. Fibers with a final denier of 3.3 dtex show a useful dumbbell-bell cross section and there is no carpel structure. The moisture content is 1.3% and the water retention is 5.5%. In spite of the many additions of ethylene carbonate, there is no change in cross-sectional structure as well as no increase in hygroscopicity with respect to standard commercial grade acrylic fibers. Different glycerols and other mentioned liquids, ethylene carbonate, are solvents for acryltonitrile polymerizers and lead to seam-free fibers.

b) Fibers without a seam-blood structure are always obtained when the ethylene carbonate content and DMF of the polyacrylonitrile spinning solution are reduced to 5% by weight or the ethylene carbonate content is reduced to 40% by weight.

c) A mixture of DMF and Y-butyrolacetone, which is also a solvent for polyacrylonitrile, is carried out in the same manner.

Claims (1)

In the method for producing hygroscopic filaments or fibers, 5 to 50% by weight of the solution having a higher boiling point than the spinning solvent used and easily mixed with both the spinning solvent and water and representing the nonsolvent relative to the spun polymer. A process for producing the hygroscopic filament or fiber having a core-blood structure by dry spinning from a filament-forming acrylonitrile polymer, characterized by adding a solid) to a spinning solvent

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