NL8102970A - CHANNEL-RESISTANT SPAN EXFIBERS. - Google Patents

Description

<N.0. 50,120 -1- j Chlorine resistant spandex fibers.

! The present invention relates to spandex fibers intended for use in a chlorinated aqueous environment such as encountered in swimming pools. In particular, the invention has! . I 'i relate to such fibers, which contain finely divided zinc oxide-

5 at. I

i Spandex fibers, made from synthetic polymers with long - grain The chain, at least 85% consisting of segmented polyurethanes, is known in the art. Yarns of such fibers have been used in the manufacture of attractive fibers, which are suitable, inter alia, for swimwear. However, the water in your pools is chlorinated to such an extent that the active chlorine content is usually between 0.5 and 3 ppm (parts per million) or higher. Exposure of polyurethane spandex fibers to such an environment can result in degradation of the physical properties (e.g., strength) of the fiber. From a practical point of view, some 1 1 degradation can be tolerated without noticing the influences! are for the user of fabrics made from these fibers. Nevertheless, improvements in the resistance to! ! chlorine induced degradation, particularly for low denier I20 yarns (e.g. less than 100 denier). It is an object of the present invention to provide such an improvement.

The present invention provides a spandex fiber with improved resistance to chlorine-induced degradation by the presence of an effective amount of finely divided high purity zinc oxide dispersed in the fiber. Zinc oxide with a content of at least 99> 4% ZnO, preferably at least 99 »7% ZnO, | is suitable for use in the present invention. Zinc oxide concentrations of 0.5% - 10% or more may be effective, but the preferred concentration of the zinc oxide is in the range of 1-3% based on the weight of the fiber. The preferred average particle size is in the range of 0.1-1 µm.

As used herein, the term fiber includes staple fibers and / or continuous filaments.

: 35 According to the present invention, the effective amount of finely divided zinc oxide can vary over a fairly wide range. Improvements in the resistance to chlorine-induced degradation have already been obtained at zinc oxide concentrations of 0.5% · 81 02 9 70 <.

-2- I! However, greater improvements are obtained when the concentrated! 1: tie is at least 1%. Although sometimes large concentrations of zinc oxide can be used in the fiber (for example, 10% or more), a concentration of less than 5% is usually used because excess | | S i; Moderate amounts of the additive adversely affect some of the physical properties of the fiber (manufactured as such) compared to the same fiber without the zinc oxide additive. j

The preferred range of concentrations of zinc oxide in the fiber is; therefore 1-3% * 10; The zinc oxide additive is divided according to the present invention. This makes a more homogeneous distribution of the zinc 1 1! 1; oxide in the fiber may then be obtained if the zinc oxide particles were larger. Generally, small particle sizes are used, such as those with an average size of less than 5 µm. Particles having an average size greater than 5 µm can lead to difficulties spinning the fiber and are therefore generally avoided. Commercially available zinc oxide particles having an average size of 0.1 µm or even slightly smaller are satisfactory. The preferred range of the average particle size is 0.1-1 µm.

High purity zinc oxide (eg at least 99> 4%!) Is suitable for use in the present invention. While less pure zinc oxide may provide some improvement, the resistance to chlorine-induced degradation provides the material of greater purity, a much better resistance to chlorine degradation and less adverse effects on the physical properties and whiteness retention of the fiber The zinc oxide of high purity can be prepared by oxidation of zinc metal, such as in the "indirect" or French process or its equivalent In contrast, the "direct" or US process does not give zinc oxide of such great purity. Among the suitable commercially available high purity zinc oxides are "AZO" -77 (sold by: - ASARC0 , Columbus, Ohio), "KAD0X" -15 (sold by New Jersey Zinc! Company !, Bethlehem, Pennsylvania), zinc oxide No. 20 or No. 911 |!.

55 (sold by St. Joe Zinc Company, Pittsburgh, Pennsylvania) and IÏ.S.P. zinc oxide (sold by Mallinckrodt, St. Louis, Missouri).

An indication of the purity of the zinc oxide is provided by the sulfur content of the zinc oxide. Elemental analysis has indicated that impurities in the zinc oxide are mostly cadmium, calcium, copper, iron, lead, magnesium, potassium, sodium, sulfur, etc.

81 02 9 7 0 -5-. A suitable measure of the general level of the contamination content of the zinc oxide is its sulfur content. The high purity zinc oxide used in the present invention generally has a sulfur content of not more than 0.025% and preferably not more than 0.005%

In the method of manufacturing spandex fibers of the present invention, the method of dissolving a long chain synthetic polymer containing at least 85% segmented polyurethane in an organic solvent and then spinning the solution by 10 openings to filaments, an effective amount of zinc oxide particles, preferably from at least 0.5 wt% to 10 wt% or more of the polymer, is dispersed in the filaments. The zinc oxide particles can be added at different times of the manufacture of the spandex fibers. For example, the zinc oxide can be added as: suspension to a solution or dispersion of other additives and | are then mixed with or injected into the polymer solution upstream of the fiber spinnerets. Of course, the zinc oxide particles can be separately added to the polymer spinning solution as a dry powder or as a suspension in a suitable medium.

As noted above, the improved spandex fibers of the present invention are made from segmented polymer polymers such as those based on polyethers, polyesters, polyether esters and the like. Such fibers are made by methods known per se, such as described in U.S. Pat. Nos. 2,929-804, 3-097,192, 5-428,711, 5,555,290, and 5,555,115. Some of these spandex polyiners are more sensitive than other polymers to the chlorine-induced degradation.

This can be seen, for example, by comparing the results of Example I, which relates to spandex fibers1 made from polyester-based polyurethane, with the results of Example II, which relates to spandex fibers made from polyester-based polyurethane. As can be seen from these examples, spandex fibers, such as those made from polyether-based polyurethanes, are more advantageous than others from the inclusion of zinc oxide particles of the invention. For this reason, embodiments of the invention involving polyether-based polyurethanes are preferred.

The spandex fibers of the invention may also contain various additives of 8102970-4 for different purposes, such as anti-glare agents, antioxidants, dyes, heat, light and smoke stabilizers, etc., as long as such additives do not have antagonistic effects with the zinc oxide produce. Also, when finishing or dyeing yarns or fabrics made from fibers of the invention, care should be taken to avoid deactivation or dissolution of the zinc oxide.

The following test methods are used to measure the various parameters discussed above.

The concentration of zinc oxide in the fiber is determined as follows. A weighed fiber sample is incinerated in a muffle furnace at 800 ° C for 10 minutes in a platinum dish. The residue thus formed is dissolved in a 50% HCl solution. Insoluble ingredients are removed by filtration. Next, according to the methods described in "Analytical Methods for Atomic Absorptions", Perkin-Elmer Corp. Norwalk, Connecticut (1973)> the filtrate analyzed with a Perkin-Elmer atomic absorption spectrophotometer model 370 (or equivalent) equipped with a zinc lamp and calibrated with a sample containing a known amount of zinc oxide. The zinc oxide concentration is then calculated as a percentage of the total weight of the fiber.

The purity of the zinc oxide can be measured by; of a potassium ferrocyanide titration as described in "Commercial methods of analysis" by E.0. Snell and P.M. Biffen, McGraw-Hill 25 Poker Company Inc. New York (1944)> p. 504 - 506.

The sulfur content of the zinc oxide can be measured by X-ray fluorescence spectroscopy. A Philips X-ray spectrometer, model PW 1400, equipped with a graphite crystal in a vacuum atmosphere and an X-ray tube with a silver 30 disc is suitable. The spectrophotometer operates at 50000 volts and 40 mA. The reaction of the alpha line of sulfur is measured according to the general guidelines of the PW 1400 operating manual published by N.Y. Philips light bulb factories, Eindhoven, the Netherlands: (1980). The instrument was calibrated by analyzing samples of zinc oxide which, by other methods, contained no detectable amounts of sulfur to which were then added known amounts of potassium sulfate.

The average size of the zinc oxide particles in the fiber is measured according to Joyce-Loebl Disc Centrifuge techniques according to methods described in "Instruction Manual for ICI-Joyce Loebl Disk 81 02 9 70 -5-

Centrifuge Mk-III with Photosedimentometer ", Joyce Loebl Co. Ltd., Durham, England. Usually the average particle size in the fiber is approximately equal to the size of the particles used in the polymer solution to make the fibers are 5. Very little reduction in particle size occurs in the process of manufacturing the fibers containing the zinc oxide.

Spandex fiber strength is defined as the product of fracture toughness and elongation at break and is measured on an Instron machine. 5 »1 cm Known denier yarn is hung between the clamps of an Instron testing machine model TM equipped with a tensile load cell of" A "capacity. The sample is stretched at a rate of 51 cm / min. The percent elongation at break (elongation at break) and the retraction force in grams M5 at yarn break, divided by the original denier of the yarn (tenacity at break) are recorded. The Whole Test: Runs at 21 ° C and 65% relative humidity after the yarns have been equilibrated under these conditions. Three test samples are averaged for each determination. Β 20 To test the resistance of the spandex fibers to chlorine induced degradation, a 20 cm sample of yarn (for example, 4-filament, 40 denier) is made from the fibers subjected to a "chlorinated water exposure test". In this test, the yarn is stretched to 150% of its original length and then immersed in a stirred state for 24 or 72 hours in a stirred water bath with a volume of about 150 liters at about 22 ° C. , a pH of 7> 5 by adding hydrochloric acid and an active chlorine concentration of 5 parts per million by adding sodium hypochlorite solution. After the exposure, the sample is dried and its physical properties are measured as described in the previous paragraph. The behavior of yarns in the chlorinated water exposure test correlates with the behavior of corresponding yarns in swimwear fabric exposed in chlorinated pools.

The concentration of chlorine in "chlorinated" water is here defined as the concentration of chlorine capable of oxidizing iodide ion to iodine. This concentration is measured by a potassium iodide, sodium thiosulfate titration and is reported as parts per million of "active chlorine" (Clg). The titration method consists of adding 20 ml of a 10% solution of potassium iodide in 8102970-6 water, 10 ml of glacial acetic acid and 5 ml of a 0.5% starch solution to 200 ml of the chlorinated water to be analyzed and titration of the mixture to a starch / iodine end point with 0.01N sodium thiosulfate.

The invention is further illustrated by, but not limited to, the following examples, in which all percentages refer to the total weight of the fibers unless otherwise indicated.

Example I.

This example illustrates the reduction obtained on chlorine-induced degradation when a dispersion of zinc oxide particles is present in a spandex yarn made of a linear segmented polyether based polyurethane.

A solution of segmented polyurethane in N, N-dimethyl-15-acetamide was prepared according to the general method described in U.S. Patent 3,442,711 (for example, the first sentence of Example II and the description of Example 1). An intimate mixture was prepared from p, p'-methylenediphenyl diisocyanate and polytetramethylene ether glycol (having a molecular weight of about 1800) in a 20 molar ratio of 1.70 and held at 80-90 ° C for 90-100 minutes for obtaining a polyether with isocyanate-terminated groups (ie, a masked glycol) which is then cooled to 60 ° C and mixed with N, N-dimethylacetamide to provide a mixture containing about 45% solids contains. Then, under vigorous mixing, the masked glycol! reacted with diethyl diamine chain extenders for 2-3 minutes at a temperature of about 75 ° C. The molar ratio of the di-. amine chain extenders to the diethylamine was 6.31, and the Imol ratio diamine chain extenders to unreacted isocyanate in the masked glycol was 0.948. The solution obtained; Segmented polyurethane contained about 36% solids and had a viscosity of about 2100 poise at 40 ° C. This polymer had an intrinsic viscosity of 0.95 measured at 25 ° C in 1-dimethyl acetamide at a concentration of 0.5 g per 100 ml solution.

To the obtained viscous polymer solution were added titanium dioxide, a copolymer of diisopropylaminoethyl methacrylate and n-decyl methacrylate (in a 70/30 weight ratio), 1,1-bis- (3-tert-butyl-6-methyl-4-hydroxyphenyl) butane and ultramarine blue pigment 40 (sold by Reckitts, Ltd., North Humberside, England), added in addition to the amounts of zinc oxide indicated in the tahel below, so that these additives are 4.7, 4.7, 1.0, respectively and 0.01% based on the weight of the final fibers. The St. Joe 20 zinc oxide, manufactured by the St. Joe Zinc Company, had a purity of 99.7% ZnO, a sulfur content of 185 ppm, and an average particle size of 0.4 µm.

The polymer solution was spun through openings in the usual way to form coalesced 4-filament, 40-: denier yarns. These yarns were then subjected to a simulated finishing treatment, during which the yarns (usually a 20 cm sample) were immersed in atmospheric pressure for 30 minutes in 3 liters of water at 80-96 ° C. containing 4.5 g of tetrasodium pyrosulfite and 4.5 g of "Duponol EP" (a cleaning agent consisting essentially of diethanolamine lauryl sulfate, sold under the trade 5; sold by EI du Pont de Nemours and Company, Wilmington, Delaware) .

The finished yarns, referred to as yarns "a" through "g", were then subjected to the "chlorinated water exposure test". The results of this exposure to the chlorinated water are summarized in the table below.

It is noted that yarn "a" and yarn "b", which were comparative yarns, containing zero and 0.26% zinc oxide, respectively, seriously deteriorated in physical properties within a very short time. For example, upon 24 hours of exposure to the chlorinated water, these two yarns were broken down to less than 10% of their original strengths in 72 hours to 2% or less. Besides! after 24 hours of exposure, yarn "c" of the present invention containing 0.7% zinc oxide retained more than 30% of its original strength and yarn "d" of the invention containing 1.3% zinc I30: Oxide retained more than 80% of its strength. Yarns "e", "f" and "g", containing 1.5, 2.1 and 2.7% zinc oxide, respectively, showed high resistance to chlorine-induced degradation. Therefore, the data in the table show that these yarns of the invention having zinc oxide contents in the preferred range of: 35 1 - 3%, retain 8-10 times their original strength after 24 hours of exposure to chlorinated water and about 40 times their original strength after 72 hours of exposure as spandexve; polyether-based scythe, in which there is no zinc oxide or ineffective amounts of zinc oxide.

40 · I

81 02 9 70 -8-

Image II.

This example illustrates the reduction obtained in the chlorine-induced degradation when a dispersion of zinc oxide particles is present in a spandex yarn made of polyester-based linear segmented polyurethane.

A polyester with hydroxyl end groups having a molecular weight of about 3400 was obtained by reacting 17.3 parts by weight ethylene glycol and 14.9 parts by weight butanol with 67.8 parts by weight adipic acid. Then, a polyester with isocyanate-terminated groups was formed by reacting at 100 ° C 100 parts by weight of the polyester with hydroxyl end groups and 13% by weight of p, p'-methylenediphenyl diisocyanate. The isocyanate-terminated polyester was then dissolved in 163.2 parts by weight of N, N-dimethyl-acetamide egg reacted with 1.30 parts by weight of ethylenediamine and 0.19 parts by weight of diethyl amine dissolved in 54.6% by weight. parts of Ν, Ν-dimethylacetamide. The resulting polymer solution was mixed with (a) the polyurethane formed as described in U.S. Pat. 3 * 555 * 115 by the reaction of tert-butyldiethanolamine and methylene-bis- (4-cyclohexylisocyanate) and (b) the condensation polymer of p-: 20icres ° 1 and divinylbenzene, as described in U.S. Pat. 290, which additives were 1.0 and 0.5 parts by weight, respectively, of the final fibers produced by spinning. The polymer solution thus prepared was spun dry in the usual manner through openings to form a coalesced 4-filament, 40-denier yarn (yarn "h"). A second yarn (yarn "i") was prepared in the same manner. as gauges "h", except that zinc oxide particles having an average size of about 1 µm manufactured by Mallinckrodt and having a purity of 99.7% ZnO and a sulfur content of 24 ppm in the polymer-150 solution were mixed before spinning. The zinc oxide content of yarn "i" was 1.4% ·

Yarns "h" and "i" were then finished as described in Example I. The yarns were then subjected to the "chlorinated water exposure test". The results are shown in the table below. It is noted that yarn "i", which contains 1.1% zinc oxide, is much better than yarn "h" (which does not contain zinc oxide) in its ability to withstand chlorine-induced degradation.

81 02 9 70 -9-

Table.

Effect of exposure to chlorinated water on yarn properties_

Mon-% Number Eek, Toughness * Strength ^,% Original star ZnO hours% gpd gpd.% Actual strength exposure a 0 0 560 1.10 610 100 24 340 0.15 50 8 10 72 150 0.05 8 1 b 0.26 0 520 0.85 440. 100 24 270 0.15 40 9 72 170 0.07 10 2: c 0.70 0 550 1.04 580 100 15; 24 440 0.42 190 34 I 72 290 0.14 40 7 d 1.30 0 440 0.92 410 100 24 430 0.79 340 83; 72 470 0.73 340 83 20 e 1.5 0 510 0.86 440 100! 24 460 0.85 400 91 i j 72, 460 0.74 340 77! ! ! f 2.1 o 460 1.01 460 100 1 24 430 0.82 350 76 25 72 450 0.77 340 74 g 2.7 0 570 0.98 560 100: 24 470 1.02 480 86 72 450 0, 80 360 64 h 0 0 760 0.55 420 100: 30: 24 700 0.31 220 52; 72 610 0.15 90 21 i 1.1 0 810 0.49 400 r 100 24 750 0.4: 5 340 85 72 750 0.41 310 77 35: Toughness is in grams per denier (gpd).

s * Strength is grams per denier toughness multiplied by% elongation: (gpd.%).

81 02 9 70

Claims (7)

Spandex fiber, characterized in that, in order to increase the fiber's resistance to chlorine-induced degradation, the fiber contains an effective amount of finely divided zinc oxide with a purity of at least 99%. Yezel according to claim 1, characterized in that the zinc oxide has a sulfur content of not more than 0.025%. Fiber according to claim 1 or 2, characterized in that the zinc oxide has a purity of at least 99% and 10%, a sulfur content of not more than 0.005%. Fiber as claimed in claims 1 to 5, characterized in that the zinc oxide concentration is in the range of 0.5-10 wt.% Of the fiber. Fiber according to claims 1 to 5, characterized in that the zinc oxide concentration in the range is 1 - 5% and the average size of the zinc oxide particles in the range is 0.1 - 1 µm A method of manufacturing a spandex fiber, wherein a long chain synthetic polymer containing at least 85% segmented polyurethane is dissolved in an organic solvent and the polymer solution thus formed is then spun dry by openings to fiber, characterized in that an effective amount of high purity zinc oxide particles are dispersed in the fiber. 7. Process according to claim 6, characterized in that zinc oxide particles with a purity of at least 99.4% and a sulfur content of not more than 0.025% and a zinc oxide concentration in the range of 0.5 - are used. 10% by weight based on the fiber. A method according to claim 6, characterized k. using zinc oxide particles with a purity of at least 99.7%> a sulfur content of not more than 0.005% and an average size in the range of 0.1 - 1 µm and providing a zinc oxide concentration in the range of 1-3 wt% based on the fiber. Process according to claims 6-8, characterized in that the zinc oxide particles are added to a mixture of other additives and then injected into the polymer solution upstream of the openings. 10. Process according to claims 6-8, characterized in that a suspension of zinc oxide particles is formed in a compatible medium and then added to the polymer solution upstream of the openings. i i I 81 02 9 70