WO2006006784A1

WO2006006784A1 - A spandex fiber with discoloration-resistance and chlorine-resistance and a method for manufacturing the same

Info

Publication number: WO2006006784A1
Application number: PCT/KR2005/002156
Authority: WO
Inventors: Byung-Su Song; Seung-Won Seo; Ji-Won Kim; Ik-Hyeon Kwon
Original assignee: Hyosung Corporation
Priority date: 2004-07-14
Filing date: 2005-07-06
Publication date: 2006-01-19
Also published as: KR100548645B1; TW200609410A; KR20060005814A; TWI281524B

Abstract

The present invention relates to a spandex fiber having excellent discoloration-resistance and chlorine-resistance and keeping the intrinsic properties of polyurethane polymers by preventing the spandex fiber from being discolored in the spinning process, and a method for manufacturing the same. The spandex fiber of the present invention contains the hydrotalcite coated with melamine-based compounds from which water of crystallization is removed. The spandex fiber of the present invention may be distinguished from that of the conventional art in that the former does not be discolored in spinning process and has excellent discoloration-resistance and chlorine-resistance. The spandex fiber of the present invention may be utilized in the field of clothes such as underwear and socks, in particular sports wear because of the excellent discoloration-resistance and chlorine-resistance.

Description

A SPANDEX FIBER WITH DISCOLORATION-RESISTANCE AND CHLORINE-RESISTANCE AND A METHOD FOR MANU¬ FACTURING THE SAME

Technical Field

[1] The present invention relates to a spandex fiber with excellent discoloration- resistance and chlorine-resistance and a method for manufacturing the same, and the spandex fiber according to the present invention may have the advantages with keeping the intrinsic properties of spandex fiber.

[2]

Background Art

[3] In general, spandex fiber has higher rubber-like elasticity, and at the same time has excellent physical properties such as high tensile force and restoration force, and hence spandex fiber has been utilized for underwear, socks and sports wear.

[4] However, if polyurethane contained in spandex as major component is washed with chloride-containing solution, the physical properties of polyurethane may be degraded heavily. And also, if a swimming wear manufactured by warp-knitting spandex and poly amide contacts chlorine water (the concentration of active chlorine is 0.5 to 3.5 ppm), the physical properties of spandex will be degraded.

[5] Efforts to improve the bad quality caused by chlorine have been made for a long time, and the results were shown in many documents in which various compounds are utilized for chlorine resistance, for example zinc oxides in US patent no. 4,340,527; mixture of huntite and hydromagnesite in US patent no. 5,626,960; calcium carbonate and barium carbonate in Korean publication no. 92-3250; MgO/ZnO solid solution in Japan publication no. H 6-81215; magnesium oxide, magnesium hydroxide or hy- drotalcite in Japan publication no. S 59-133248; hydrotalcite coated with higher fatty acid and silane coupling agent in Japan publication no. H 3-292364; hydrotalcite coat ed with stearic acid and inevitably comprising water of crystallization in US patent no. 5,447,969; hydro-talcite coated with melamine-based compounds in US patent no. 6,692,828. And Europe publication number EP 1,262,499 Al describes the hy¬ drotalcite of which the average particle size is less than 1 um by ball-milling.

[6] According to US patent no. 5,447,969, in particular, hydrotalcite is coated with strearic acid and inevitably has water of crystallization, and hence the aggregation of hydrotalcite can be avoided in manufacturing process of spandex and the rise of discharge pressure and yarn breakage can be avoided in spinning process, and also, spandex would not be turned brown and would not be swollen in dying process and in process of treatment with tannin solution because the hydrotalcite has water of crys¬ tallization. And the document reports that a phenomenon that spandex is turned yellow-brown does not happen in dry spinning at the hot atmosphere of 330 ⁰C.

[7] But it was found that spandex was turned yellow-brown when spandex polymer containing the hydrotalcite coated with fatty acid and having water of crystallization according to US patent no. 5,447,969 is spun at the hot atmosphere of 250 ⁰C.

[8] In general, even though chlorine -resistance is excellent, the discolored spandex may be inevitably devaluated and also a problem that it is impossible to dye spandex white may happen in dyeing and finishing process, and hence an improvement to overcome the problem has been required.

[9] And also, according to US patent no. 5,447,969 spandex may not be discolored in dying process and in process of treatment with tannin solution and not be swollen only when hydrotalcite with water of crystallization is utilized, but it has been found that the spandex may not be discolored and swollen even though the spandex yarn made of polymer containing the hydrotalcite without water of crystallization is dyed and treated with tannin solution.

[10] According to US patent no. 6,692,828, in the case of using hydrotalcite coated with melamine-based compounds with excellent heat-resistance, spandex was also the same discolored as US patent no. 5,447,969 in dry spinning within hot atmosphere at the temperature of 250 ⁰C even though the discolorization degree of US patent no. 6,692,828 is less than that of US patent 5,447,969.

[11] And Europe patent no. EP 1,262,499Al describes the method to add the hy¬ drotalcite after being ground with milling device to the polymer, but the method is well known to the skilled in this art. And also, in the above-mentioned method, uncoated hydrotalcite without water of crystallization is utilized. If the uncoated hydrotalcite is added to spandex polymer, aggregation and gel may happen in manufacturing process in spite of sufficient dispersion with a milling device. Therefore, it is important to use the coated hydrohtalcite.

[12] Referring to the structural formula of the hydrotalcite shown in EP 1,262,499Al, in contrast with the conventional arts, a part of carbonic ions are decomposed and small amount of oxygen is included in the hydrotalcite. The above-mentionded structure of the hydrotalcite may indicate that the hydrotalcite is heat-treated at higher than 300 ⁰C and the crystal structure is collapsed somewhat. The crystal structure of hydrotalcite and the content of carbonic ions in hydrotalcite are important factors for endowing the chlorine resistance to the spandex fiber, and hence if the hydrotalcite in which the crystal structure is collapsed somewhat and the content of carbonic ions are small is added to the spandex polymer, the chlorine resistance of the spandex fiber may be degraded. [13] For testing the above-mentioned art, hydrotalcite which contains some oxygen and in which a part of carbonic ions is decomposed was prepared by being heated at higher temperature than 300 ⁰C, as described in EP 1,262,499Al. And then, that was mixed with spandex additives in dimethylacetamide to prepare slurry, and subsequently the slurry was ground with milling device to be added to the spandex polymer for manu¬ facturing the spandex yarn.

[14]

Disclosure of Invention

Technical Problem

[15] The discoloration of spandex was not shown in spinning process at higher temperature than 200 ⁰C, but the clogging of spinning filter and the yarn breakage of spandex happened in spinning process. The phenomenon presumably might be caused from the fact that even though the slurry containing hydrotalcite was sufficiently ground with the milling device, the water absorption and the aggregation of the hy¬ drotalcite within the polymer happened rapidly because the hydrotalcite was uncoated. And the chlorine-resistance of the final yarn was worse than that of the other yarns prepared by the other conventional arts.

[16]

Technical Solution

[17] According to the present invention, for solving the problems of conventional arts, hydrotalcite is coated with melamine-based compounds with excellent heat-resistance, and water of crystallization is removed from the hydrotalcite under the condition that carbonic ions are not decomposed by heat-treating at lower temperature than 300 ⁰C. And this hydrotalcite is added to polymer to produce spandex having excellent dispersion of the hydrotalcite, discoloration-resistance in spinning process at higher temperature than 200 ⁰C and excellent chlorine-resistance.

[18] It is an object of the present invention to provide the hydrotalcite-containing spandex fiber with non-discoloration and chlorine resistance even though a raw yarn is produced by melt-spinning or dry-spinning at higher temperature than 200 ⁰C.

[19] In this specification and accompanied claims, the term "spinning" or "spinning process" comprises both melt-spinning and dry spinning, and the term "spinning temperature" means maximum temperature of spandex polymer in spinning process, for example the temperature for melting polymer chip in melt- spinning process or the temperature of the spinning chamber in dry-spinning process. And discoloration means that fiber turns some color, for example yellow or brown, other than white.

[20]

Advantageous Effects [21] According to the present invention, a spandex fiber with excellent discoloration- resistance and chlorine-resistance can be provided. And also, the spandex fiber of the present invention can be utilized for underwear, socks and in particular sports wear such as swimming wear.

[22]

Best Mode for Carrying Out the Invention

[23] For achieving the above-mentioned object, the spandex fiber contains 0.1 to 10 wt

% of the hydrotalcite based on the weight of the spandex fiber, coated with 0.1 to 10 wt% of melamine-based compounds based on the weight of hydrotalcite, and without water of crystallization.

[24] And also, the hydrotalcite may be preferably represented by the following structural formula (1):

[25] M²⁺ x Al m (OH) y (A^n~) z (1),

[26] wherein M ⁺ represents Mg ⁺or Zn ⁺, Aⁿ represents an any anion with n valences, x and y represent 2 or any positive number bigger than 2, and Z and m represent any positive number. Further, A^n~ may represent any one among OH ,F ,Q ,Br ,NO ,SO

3 4

,CH COO ₅CO ² ,HP0 ^2",Fe(CN) ^3", oxalate ion and salicylate ion.

3 3 4 6

[27] And also, the hydrotalcite may be at least one compound selected from a group consisting of the following compounds (2) to (5): [28] Mg₄₅Al₂(OH)_i3CO₃ — - (2)

[29] Mg Al (OH) CO — - (3)

[30] Mg Al (OH) CO — - (4)

8 2 20 3

[31] Mg Al (OH) CO -— (5)

[32] And also, preferably the melamine-based compounds may comprise at least one compound selected from a group consisting of melamine compounds, phosphorus- combined melamine compounds, melamine cyanurate compounds, melamine compounds substituted with organic compounds having carboxyl groups, phosphorus- combined melamine compounds substituted with organic compounds having carboxyl groups, melamine cyanurate compounds substituted with organic compounds having carboxyl groups.

[33] And also, the weight of the hydrotalcite without water of crystallization is reduced less than 3 wt% when dried at the temperature of 240 ⁰C for 2 hours.

[34] And also, a method for producing spandex fiber with excellent discoloration- resistance and chlorine-resistance may comprise the steps of removing the water of crystallization by heating and drying hydrotalcite at the temperature of 180 to 250 ⁰C and adding the hydrotalcite to spandex polymer for spinning.

[35] The hydrotalcite may preferably be coated with 0.1 to 10 wt% of melamine-based compounds.

[36] The method for producing spandex fiber with excellent discoloration-resistance and chlorine-resistance will be described in detail in the following.

[37] In the explanation of the present invention, it should be understood that the terms used in this specification is defined considering the function of the present invention and the meaning will be modified according to the intent of the skill in this art, without limiting the function of the components of the present invention.

[38] According to the present invention, for avoiding the discoloration of the spandex yarn in spinning process at higher temperature than 200 ⁰C, hydrotalcite coated with 0.1 to 10 wt% melamine-based compounds may be heat-treated for removing interlay er water, namely water of crystallization. And then the hydrotalcite is added to spandex polymer to spin. The coating agent of hydrotalcite may comprise fatty acid, fatty acid ester, fatty acid salts, phosphonic acid ester, styrene/maleic acid anhydride copolymer and derivatives thereof, silane coupling agent, titanate coupling agent, poly- organosiloxane, polyorgano hydrogen siloxane and melamine-based compounds. And the most desirable materials for coating are the melamine-based compounds with excellent heat-resistance because those are not discolored even though the other coating materials may be discolored during heating process of removing water of crys¬ tallization from the hydrotalcite.

[39] For preventing spandex raw yarn from being discolored in spinning process at higher temperature than 200 ⁰C, the hydrotalcite coated with melamine-based compounds is heat-treated to remove water of crystallization from that and then added to spandex polymer, and the resulting spandex raw yarn made of the spandex polymer has excellent discoloration-resistance and chlorine-resistance.

[40] The hydrotalcite used for producing spandex of the present invention may be represented by the following structural formula (1)

[41] M ⁺ Al (OH) (A^n~) — (1), wherein M ⁺ represents Mg ⁺ or Zn ⁺, A^n~ represents an x m y z any anion with n valences, x and y represent 2 or any positive number more than 2, and z and m represent positive number. A^n~ may be any one ion selected from a group consisting of OH , F , Cl , Br , NO , SO ² ,CH COO ₅ CO ² , HPO ² , Fe(CN) ^3",

3 4 3 3 4 6 oxalate ion and salicylate ion, and the formulas of hydrotalcite suitable for being used in the spandex fiber of the present invention preferably may be represented in the following (2) to (5).

[42] Mg Al (OH) CO — - (2)

[43] Mg 6 Al 2 (OH) 16 CO 3 — - (3)

[44] Mg Al (OH) CO — - (4)

°8 2 20 3

[45] Mg₄Al₂(OH)₁₂CO₃ -- - (5)

[46] The above-mentioned formulas of the hydrotalcite represent the hydrotalcite from which interlayer water or water of crystallization is removed.

[47] Melamine-based compounds may preferably comprise melamine compounds, phosphorus -combined melamine compounds, melamine cyanurate compounds, melamine substituted with organic compounds having carboxyl groups, phosphorus- combined melamine compounds substituted with organic compounds having carboxyl groups, melamine cyanurate compounds substituted with organic compounds having carboxyl groups, and the above-mentioned compounds may be used individually or in mixture.

[48] Melamine compounds may comprise methylene dimelamine, ethylene dimelamine, trimethylene dimelamine, tetramethylene dimelamine, hexamethylene dimelamine, de- camethylene dimelamine, dodecamethylene dimelamine, 1,3-cyclohexylene dimelamine, p-phenylene dimelamine, p-xylene dimelamine, diethylene trimelamine, triethylene tetramelamine, tetraethylene pentamelamine, hexaethylene heptamelamine and melamine formaldehyde.

[49] Phosphorus-combined melamine compounds may comprise melamine compounds associated with phosphoric acid or phosphate, for example dimelamine pyrophosphate, melamine primary phosphate, melamine secondary phosphate, melamine polyphosphate, melamine salts reacted with bis-(pentaerythritol phosphate) phosphoric acid.

[50] Melamine cyanurate compounds may comprise melamine cyanurate compounds un- substituted or substituted with at least one selected from a group of methyl, phenyl, carboxymethyl, 2-carboxymethyl, cyanomethyl and 2-cyanoethyl.

[51] Advantageously melamine-based compounds may be substituted with organic compounds having carboxyl groups. Organic compounds having carboxyl groups may comprise aliphatic mono-carboxylic acid such as caprylic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, hexadecanoic acid, hep- tadecanoic acid, stearic acid, nonadecanoic acid, eicosanoic acid and behenic acid, aliphatic dicarboxyl acid such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaric acid, sebasic acid, 1,9-nonanedicarboxyl acid, 1,10-decanedicarboxyl acid, 1,11-undecanedicarboxyl acid, 1,12-dodecanedicarboxyl acid, 1,13-tridecanedicarboxyl acid or 1,14-tetradecanedicarboxyl acid aromatic mono- carboxylic acid such as benzoic acid, phenylacetic acid, alpha-naphthoic acid, beta- naphthoic acid, cynnamic acid, p-amino hippuric acid and (4-(2-thiazo(l)ylsulfamyl)-phthalaninoic acid, aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid and phthalic acid, aromatic tricarboxylic acid such as trimellitic acid, 1,3,5-benzenetricarboxylic acid and tris(2-carboxyethyl) isocyannurate, aromatic tetracarboxylic acid such as pyromellitic acid and biphenyltetracarboxylic acid, aliphatic cyclic monocarboxylic acid such as cyclohexane carboxylic acid and aliphatic cyclic dicarboxylic acid such as 1,2-cyclohexane dicarboxylic acid.

[52] The coating agent content of the hydrotalcite according to the present invention preferably may be 0.1 to 10 wt% based on the total weight of hydrotalcite. If the weight of the coating agent is less than 0.1 wt%, then the coating effect may be negligible, while if more than 10 wt%, then the manufacturing cost may increase without further effect.

[53] The method for coating the hydrotalcite particles comprises adding the coating agent to a solvent such as water, alcohol, ether and dioxane in amount of 0.1 to 10 wt% based on the weight of the hydrotalcite, and then adding hydrotalcite to the solvent. The solvent is being stirred with being heated until 50 to 170 ⁰C and, if necessary, a high pressure reactor may be used. The coating reaction continues for 30 to 120 minutes and then hydrotalcite is obtained through filtering and drying. An alternative coating method is a physical mixing method that involves mixing the melamine-based compounds dissolved in a solvent with hydrotalcite by means of a high speed mixer and drying the mixture.

[54] The coating agent prevents hydrotalcite from absorbing humidity and improves the dispersion of the hydrotalcite in polymer, so it can avoids the deterioration of spinning property due to gel possibly formed in the polymer. And the discoloration of coating material cannot happen even though heat-treatment process may be performed for removing water of crystallization within hydrotalcite because melamine-based compounds has excellent heat-resistance. When the coated hydrotalcite is used after removing of water of crystallization, it is important to reduce the time for the hy¬ drotalcite to contact the air and immediately to wrap the hydrotalcite for preventing humidity from being absorbed. If the temperature for heat-treating is higher than 300 ⁰C, the hydrotalcite structure may be altered or the discoloration of coating material may happen. And hence it is important to heat-treat within the temperature at which the hydrotalcite structure may not be altered and the coating material may not be discolored.

[55] The present invention will be described in detail in the following.

[56] The present invention is characterized in that water of crystallization withi[n hy¬ drotalcite is removed in specific temperature. The water of crystallization within hy¬ drotalcite exist not on outer surface (surface water) of hydrotalcite but in the form of water of crystallization that is interlayer water in hydrotalcite, and generally the content of interlayer water before being removed from the hydrotalcite may amount to about 12 wt%. The water of crystallization, that is interlayer water generally means the moisture which is evaporated on heating at temperature of 180 to 300 ⁰C not with a vacuum hear dryer, but with a common convection oven. If the hydrotalcite is dried below 180 ⁰C, then the time for removing water of crystallization may be too long, while if above 300 ⁰C, then the structure of the hydrotalcite starts to collapse with being changed into oxides of Mg and Al. The temperature of a spinning chamber in spinning process of spandex remains at 200 to 300 ⁰C for evaporating and recycling the organic solvent. It was found that at such range of temperature spandex polymer containing the hydrotalcite with interlayer water is discolored. The surface water of hy¬ drotalcite which is evaporated at the temperature of about 100 ⁰C cannot discolor spandex fiber in spinning process.

[57] It was found that the preferable temperature for removing the interlayer water from hydrotalcite is at the range of 180 to 250 ⁰C. If the temperature is below 180 ⁰C, then the time for removing the interlayer water from hydrotalcite is too long, while if above 250 ⁰C, then the coating material of hydrotalcite may be discolored or decomposed.

[58] Any method for heating and drying hydrotalcite may be used only if the temperature is kept above 180 ⁰C, and the method may comprise convection, conduction and radiation, etc. A microwave or a vacuum heating dry method developed recently may be used.

[59] A way to verify whether the interlayer water within hydrotalcite is or not that the initial weight of dried hydrotalcite is compared with that of the later weight of the dried hydrotalcite after being dried additionally. If the reduction rate % of weight is equal to or less than 3 wt% after drying additionally for 2 hours at 240 ⁰C temperature, then it is assumed that the interlayer water is removed (see the method for checking whether the interlayer water is removed or not). If the interlayer water of hydrotalcite is not removed, then the reduction percent of the weight is more than 12 wt% after drying for 2 hours at temperature of 240 ⁰C. The reason that the reduction percent of the weight is equal to and less than 3 wt% in checking the removement of the interlayer water is that hydrotalcite absorbs moisture in the air rapidly and instantly on contacting the air even though all of the interlayer water within the hydrotalcite is removed. The heat-treated hydrotalcite may be wrapped with aluminum packing materials for preventing humidity from being absorbed.

[60] And uncoated hydrotalcite which is heat-treated for removing the interlayer water and lies in the air absorbs moisture more rapidly than coated hydrohthalcite which is heat-treated for removing interlayer water and lies in the air. Therefore, the coated hy¬ drotalcite is preferably used for storing as well as other objects.

[61] The content of hydrotalcite in spandex according to the present invention is preferably 0.1 to 10 wt%. If the content is less than 0.1 wt%, then the effect of chlorine-resistance is negligible, while if more than 10 wt%, then the strength, elongation and modulus of spandex are degenerated due to containing excess inorganic compound.

[62] The average particle size of hydrotalcite according to the present invention preferably is equal to or less than 10 um, and more preferably less than 5 um in the process application. The average particle size of the hydrotalcite exceeding 10 um may result in the rise of pack pressure and yarn breakage in spinning process.

[63] Polyurethane polymer used for producing spandex fiber of the present invention is prepared, as known to the skilled in this art, and according to the method polyurethane precursor is prepared by reacting organic diisocyanate and polymer diol, and then the precursor is dissolved in organic solvent to react with diamine and monoamine for producing polyurethane-urea polymer.

[64] Organic diisocyanate used in the present invention may comprise diphenylmethane-

4, 4'-isocyanate, hexamethylene isocyanate, toluene diisocyanate, butylene di¬ isocyanate, hydrogenated P, P-methylene diisocyanate, etc. Polymer diol may comprise polytetramethylene ether glycol, polypropylene glycol and polycarbonate diol, etc. Diamines may be used as chain extenders, and comprise ethylene diamine, propylene diamine, hydrazine and the like. And also, monoamines may be used as chain terminator, and comprise diethyl amine, mono-ethanol amine and dimethyl amine and the like.

[65] In the present invention, stabilizers such as hindered phenol compounds, benzofuran-one compounds, semi-carbazide compounds, benzotriazol compounds, hindered amine compounds, polymeric tertiary amine stabilizers such as poly urethane with tertiary nitrogen atom and polydialkylaminoalkyl methacylate may be added to spandex polymer to prevent the discoloration and the degradation of spandex caused by ultra-violet ray, smog and the heat-treatment during the down stream process of the spandex.

[66] The spandex fiber of the present invention may further comprise additives such as titanium dioxide, magnesium stearate, etc. Titanium dioxide may be added to the spandex polymer in the amount of 0.1 to 5 wt %, based on the total weight of the spandex fiber, depending on the degree of white color of spandex. And also, Magnesium stearate is added to the spandex polymer in the amount of 0.1 to 2 wt%, based on the total weight of the spandex fiber to improve the unwinding property of the spandex fiber from the bobbin.

[67] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and it is intended to provide further explanation of the invention as claimed.

[68]

Mode for the Invention

[69] Example

[70] Example 1 to 4, comparison 1 to 5 [71] 518 g of diphenylmethane-4, 4-diisocyanate and 2328 g of polytetramethylene-ether glycol (molecular weight 1800) were reacted with stirring at 80⁰C in nitrogen atmosphere for 90 minutes to prepare a polyurethane prepolymer. The pre-polymer was cooled to the room temperature, and then 4269g of dimethylacetamide was added to the prepolymer to obtain polyurethane pre-polymer solution. Subsequently, 34.4 g of ethylene diamine, 10.6 g of propylene diamine and 9.1 g of diethyl diamine were dissolved in 1117 g of dimethylacetamide to obtain the amine solution. The amine solution is added to the prepolymer solution at the lower temperature than 10⁰C to prepare a polyurethane-urea solution.

[72] Based on the total weight of the solid of the polyurethane-urea solution, 1.5 wt% of such as ethylene bis(oxyethylene) bis-(3-(5-t-butyl-4-hydoroxy-m-toil)-propionate), 0.5 wt % of 5,7-di-t-butyl-3-(3,4-dimethyl phenyl)-3H-benzofuran-2-one, lwt % of 1,1,1'r-tetramethy 1-4-4 -(methylene-di-p-phenylene)disemicarbazide, 1 wt% of poly(N,N-diethyl-2-aminoethyl methacrylate), 0.1 wt % of titanium dioxide, 0.5 wt % of magnesium stearate and hydrotalcite (example 1 to 4 and comparison 1 to 5) as shown in Table 1 and Table 2 were added to the polyurethane-urea solution to prepare a spinng solution of the polyurethane-urea.

[73] The above-mentioned additives were dispersed and ground in dimethylacetamide by using of Advantis V3 apparatus made in Drais Mannheim Co., Germany, before they were added to the poly urethane-urea solution.

[74] After defoaming the spinning solution of the polyurethane-urea, that solution was spun in dry spinning chamber of which the upper part temperature was 250 ⁰C to prepare a 40-denier spandex fiber consisting of 4 filaments, and then the physical properties were estimated to be shown in table 1 and table 2.

[75] <Chlorine-resistance test>

[76] Test of strength preservation rate in chlorinated water: The Spandex yarn subjected to 50 % stretching was treated with a water( pH 4.2, at 97 ⁰C to 98 ⁰C) for 2 hours and cooled at the room temperature. And after being dipped in 45 L of chlorinated water(pH 7.5) containing 3.5 ppm of active chlorine for 24 hours, the spandex yarn was analyzed in regard to strength preservation rate.

[77] * Strength preservation rate (%) = S/S X 100

[78] (S : strength before treatment, S: strength after treatment)

[79] * An Instron 4301(Instron Co., USA) was used for strength measurement, where the sample piece was 5 cm long and the cross head speed was 300 mm/min with 1 Kg of a cell.

[80]

[81] <Method for checking whether the interlayer water in hydrotalcite is removed or not> [82] Whether the interlay er water in the hydrotalcite to be added to the polyurethane- urea solution was or not was checked by measuring and comparing the weight of the hydrotalcite with that of the hydrotalcite after being dried at 240 ⁰C for 2 hours.

[83] (i) An aluminum foil was weighed after the foil was dried for 30 minutes: (A) [84] (ii) The foil with a sample was weighed:(B) [85] (iii) The foil was dried in a convection oven at the temperature of 240 ⁰C +5 ⁰C for 2 hours.

[86] (iv) The sample was weighed in hot state immediately after being taken out from the convection oven: (C) [87] (v) The amount of loss on drying was calculated according to the following equation.

[88] Loss on drying (%) = [1-(C-AV(B-A)] X 100 [89] (vi) If the loss on drying was equal to or less than 3 wt%, then it was regarded as that the interlayer water was not.

[90] <Method for estimating yellowness of spandex yarn> [91] The yellowness value "b" of a bobbin that the spandex yarn was wound to 3.7 cm in height and 4 cm in width on a paper tube having 8.5 cm of outer diameter and 5.7 cm of width was measured with a Color- view spectrophotometer (BYK-Gardener Co., US) (Test condition: Instrument Geometry = 45 / 0 , Illuminant/ Observer= D65/10 , 11 mm sample port aperture was used,and the number of tests was 3).

[92] [93] Table 1

[94] [95] Table 2

[96]

[97] note)

[98] CC : coating material

[99] CA : coating weight %, based on the total weight of hydrotalcite

[100] Hy : hydrotalcite

[101] A.Hy : hydrotalcite weight %, based on the total weight of spandex yarn

[102] S.P.R : strength preservation rate (%) of spandex yarn after chlorinated water treatment after 24 hours

[103] Y.v : yellowness value(b value) of the bobbin [104] S.w : the number of times of yarn breakage per hour during spinning process [105] * The less "b" value is, the less discolored is the bobbin. [106] [107] As shown in table 1 and table 2, when the hydrotalcite which was coated with melamine-based compounds and from which the interlayer water was removed was used, spandex was not discolored and had excellent chlorine -resistance and spinning work efficiency even at higher temperature than 200 ⁰C

[108] When the hydrotalcite which was uncoated and from which interlayer water was removed was used, the discoloration didn't occur, but the sipinning work efficiency and the chlorine resistance was degraded.

[109] In particular, when the hydrotalcite which was uncoated and in which some of carbonate ions was decomposed and of which the structure was somewhat broken, as described in EP 1,262,499 Al, was used, the spinning work efficiency and the chlorine-resistance was much degraded.

[HO] The present invention was described in the foregoing in detail with examples, but it should be understood that the modification and the adjustment of the examples can be made by the skilled in this art in the scope of the present invention. The scope of the present invention will be limited only by the accompanied claims.

[I l l]

Industrial Applicability

[112] The present invention is applicable to a spandex fiber with excellent discoloration- resistance and chlorine-resistance and a method for manufacturing the same, and the spandex fiber according to the present invention may have the advantages with keeping the intrinsic properties of spandex fiber.

Claims

[1] L A spandex fiber with excellent discoloration-resistance and chlorine-resistance comprising, 0.1 to 10 wt% of hydrotalcite based on the total weight of the spandex fiber, wherein the hydrotalcite is coated with 0.1 to 10 wt% of melamine-based compounds based on the weight of the hydrotalcite and the interlayer water is not in the hydrotalcite.

[2] 2. The spandex fiber according to claim 1, wherein the hydrotalcite are represented by the following structural formula: M ⁺ xAl m (OH) y (A^n~) z (1), wherein M ⁺ represents Mg ⁺or Zn ⁺, A^n~ represents an any anion with n valence, x and y represent 2 or any positive number more than 2, and Z and m represent positive number. Aⁿ represents OH ,F ,Cl ,Br ,NO ^",SO₄ ² ,CH₃COO ,CO₃ ^2",HPO₄ ^2",Fe(CN)_g ^3", oxalate ion and salicylate ion. [3] 3. The spandex fiber according to claim 1, wherein the hydrotalcite particles are represented by at least one selected from a group consisting of the following (2) to (5): Mg Al (OH) CO — - (2)

45 2 13 3

Mg₆Al₂(OH)₁₆CO₃ - - (3) Mg Al (OH) CO — - (4)

8 2 20 3

Mg Al (OH) CO — - (5).

4 2 12 3

[4] 4. The spandex fiber according to claim 1, wherein the melamine-based compounds comprise at least one compound selected from a group consisting of melamine compounds, phosphorus -combined melamine compounds, melamine cyanurate compounds, melamine compounds substituted with organic compounds having carboxyl groups, phosphorus-combined melamine compounds substituted with organic compounds having carboxyl groups and melamine cyanurate compounds substituted with organic compounds having carboxyl groups.

[5] 5. The spandex fiber according to claim 1, wherein loss on drying(%) is equal to or less than 3 wt% when the hydrotalcite from which the interlayer water is removed is dried at the temperature of 240 ⁰C for 2 hours.

[6] 6. A method for manufacturing a spandex fiber with excellent discoloration- resistance and chlorine-resistance comprising the steps of: removing the interlayer water from hydrotalcite by heating and drying at the temperature of 180 ⁰C to 250 ⁰C; adding the hydrotalcite to a spandex polymer; and spinning the spandex polymer to produce the spandex fiber.

[7] 7. The method according to claim 6, wherein the hydrotalcite is coated with 0.1 to 10 wt% of a melamine-based compounds compared based on the weight of the hydrotalcite.