SHIN, Ickgy (1579-6 Oncheon3-dong, Dongnae-gu, Busan 607-063, KR)
JUNG, Inrak (1 Ildong Mirajoo APT, 725-1 Yaeum3-dong Nam-gu, Ulsan 680-840, 01-1503, KR)
JEONG, Sang Ok (102-104 Singaegeum LG APT, 596 Gaegeum-dong Busanjin-gu, Busan 614-751, KR)
KIM, Wan Ouk (107-902 Woosung APT, Noryangjin1-dong Dongjak-gu, Seoul 156-751, KR)
LEE, Young Kyong (304 LEEGEON Heights Ville, 1183-6 Yongwon-dong Jinhae-si, Gyeongsangnam-do 645-510, KR)
NANOTECHCERAMICS CO., LTD (1522-7, Songjeong-dong Gangseo-gu, Busan 618-817, KR)
CHOI, Okhyun (2 Munsu I-Park APT, Sinjeong2-dong Nam-gu, Ulsan 680-012, 02-2104, KR)
SHIN, Ickgy (1579-6 Oncheon3-dong, Dongnae-gu, Busan 607-063, KR)
JUNG, Inrak (1 Ildong Mirajoo APT, 725-1 Yaeum3-dong Nam-gu, Ulsan 680-840, 01-1503, KR)
JEONG, Sang Ok (102-104 Singaegeum LG APT, 596 Gaegeum-dong Busanjin-gu, Busan 614-751, KR)
KIM, Wan Ouk (107-902 Woosung APT, Noryangjin1-dong Dongjak-gu, Seoul 156-751, KR)
LEE, Young Kyong (304 LEEGEON Heights Ville, 1183-6 Yongwon-dong Jinhae-si, Gyeongsangnam-do 645-510, KR)
[CLAIMS]
[Claim l]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber comprising a polyfunctional alcohol and an isocyanate compound, which is characterized in that it comprises 0.1-10% by weight of basic magnesium carbonate coated with one or more substance (s) selected from
C1-C30 fatty acids, fatty acid metal salts, fatty acid esters, fatty acid phosphoric esters, silica, silane, polyorganosiloxanes, and polyorganosiloxane/polyorganohydrogensiloxane mixtures via dry or wet process, as a chlorine resistant additive.
[Claim 2] A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim 1, wherein the amount of said coating agent coated or encapsulated is 1-20 parts by weight based on the basic magnesium carbonate.
[Claim 3]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim 1, wherein the structure of said basic magnesium carbonate is represented by Chemical Formula 1 :
M 2+ x (A n" ) y M 2+ (OH) z -mH 2 0 (1) wherein, M 2+ is Mg 2+ or Ca 2+ , A n' is CO 3 2" , x is 1-5 , y is 1-5 , z is 0-2 , and m is 0-5 . [Claim 4 ]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim 3, wherein said basic magnesium carbonate is represented by one of Chemical Formulas 2-6:
Mg 4 (CO 3 J 4 Mg (OH) 2 -4H 2 O (2)
Mg 3 (COa) 3 Mg (OH) 2 -3H 2 O (3)
Mg 4 (CO 3 J 4 Mg(OH) 2 (4)
Mg 3 (CO 3 ) 3 Mg(OH) 2 (5)
MgCO 3 ( 6 )
[Claim 5]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim 4, wherein said basic magnesium carbonate is one or more substance (s) selected from hydromagnesite, dihydromagnesite and magnesite.
[Claim 6]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim 1, wherein the activity of said basic magnesium carbonate may be enhanced by removing the surface water or crystal water partly via thermal treatment at 300 "C or less, or completely via thermal treatment at 400 ° C or more. [Claim 7]
A composition for preparing a chlorine resistant polyurethaneurea elastic fiber according to claim I 7 wherein the mean particle size of said basic magnesium carbonate is 10 μm or less . [Claim 8]
A process for preparing a polyurethaneurea elastic fiber, which is characterized in that a composition according to any ¬ one of claims 1 to 7 is spun under the condition of temperature of 240-255 ° C immediately downstream the spinning nozzle, and a spinning rate of 700-1200 m/min.
[Claim 9]
A chlorine resistant polyurethaneurea elastic fiber which employs a composition according to any one of claims 1 to 7. [Claim lθ]
A chlorine resistant polyurethaneurea elastic fiber prepared according to the process of claim 8. |
CHLORINE RESISTANT POLYURETHANEUREA COMPOSITION
[Technical Field] The present invention relates to compositions for preparing polyurethaneurea elastic fiber having excellent chlorine resistant property and uniformity, high durability against chlorine-containing water of a swimming pool and excellent quality as a cloth material after mixture-knitting with nylon, and a chlorine resistant polyurethaneurea elastic fiber prepared by using the same.
[Background Art]
Polyurethaneurea elastic fiber is prepared by dry or melt Spinning of a polymer obtained from chain extension of a prepolymer having isocyanate end group, which was synthesized from a high molecular weight polyol and excess amount of organic diisocyanate, with a diamine; and finds its use as an elastic functional material for various clothes such as foundation garments, socks, panty hoses and swimming wears by means of mixture-knitting with polyamide fiber, polyester fiber or a natural fiber.
The polyurethaneurea elastic fiber is deteriorated in physical properties, since the polyetherglycol structure
constituting the soft segment of the polymer is decomposed by chlorine-containing bleach water or active chlorine in a swimming pool for disinfection. Therefore, in order to improve chlorine resistant property of polyurethaneurea elastic fiber employed for a swimming wear, polyurethane elastic fibers using polyesterglycol have been developed. However, aliphatic esters, having high biological activity, are apt to be attacked by fungi, with insufficient chlorine resistance. In order to improve chlorine resistance of polyether polyurethanes, various chlorine resistant additives have been used. Japanese Patent 1982-29609 and USP 4,340,527 used zinc oxide to improve the chlorine resistant property. However, zinc oxide is troublesome since it turns yellow upon reacting with an additive, and it is eluted under acidic dyeing condition at pH 3~4. In particular, zinc components cannot be used in Europe, being a regulatory substance for environment. Japanese Patent 1984-133248 employed hydrotalcite to improve chlorine resistant property. However, hydrotalcite used as a chlorine resistant additive was so hygroscopic that it caused problems of increasing gel formation of the polymer, increasing of filter pressure and reducing of spinning ability. Japanese Patent 1991-243446 employed a hydrotalcite coated with a fatty acid to prevent water absorption of the chlorine resistant additive and to improve dispersiveness, thus
enhancing the chlorine resistant property of polyurethaneurea elastic fiber. However, the hydrotalcite reacts with additives employed for light resistance and gas resistance of the polyurethaneurea elastic fiber, to convert the color of the product yellow during the spinning. USP 5,626,960 employed a mixture of Huntite and hydromagnesite to enhance chlorine resistant property. However, according to the patent, the chlorine resistant material was not coated so that problems of gel formation of the polymer due to hygroscopicity of the material and poor dispersion occurred to increase the filter pressure and fiber breakage rate, and the final product turned yellow.
[Disclosure] [Technical Problem]
An object of the present invention is to provide a composition for preparing polyether polyurethaneurea elastic fiber having excellent chlorine resistant property.
Another object of the present invention is to provide an additive to supplement anti-oxidation, light resistance and waste gas resistance of polyurethane elastic fiber, a chlorine resistant additive and an additive composition having good compatibility with polyurethaneurea, and to prepare polyurethaneurea elastic fiber by using the same.
[Technical Solution]
In order to achieve the objects as described above, the present invention provides polyurethaneurea elastic fiber by- using basic magnesium carbonate as a chlorine resistant additive. While the basic magnesium carbonated employed in the present invention may be used without being coated, it is advantageously employed with organic or inorganic coating to enhance dispersiveness and moisture resistance.
The composition for preparing chlorine resistant polyurethaneurea elastic fiber according to the present invention is characterized in that it comprises 0.1-10% by weight of basic magnesium carbonate coated with one or more substance (s) selected from C1-C30 fatty acids, fatty acid metal salts, fatty acid esters, fatty acid phosphoric esters, silica, silane, polyorganosiloxanes, and polyorganosiloxane/polyorganohydrogensiloxane mixtures via dry or wet process, as a chlorine resistant additive.
In addition, the present invention provides a polyurethaneurea elastic fiber having enhanced chlorine resistant property by adding a coated basic magnesium carbonate during the preparation of the polyurethaneurea elastic fiber as a chlorine resistant additive together with other additives .
The processes for preparing the basic magnesium carbonate
employed in the present invention include a soda ash process which utilizes a reaction of soluble magnesium salt such as magnesium chloride with sodium carbonate, a carbo-stable process which utilizes a reaction of soluble magnesium salt with ammonium carbonate, a gas process which utilizes a reaction of magnesium hydroxide with carbonic acid gas, and the like.
According to these processes, normal magnesium carbonate (represented by chemical formula MgCO 3 ^nH 2 O, usually n=3) or magnesium bicarbonate (Mg (HCO 3 ) 2 ) obtained as an intermediate from the reaction of the magnesium source with the carbonate source is subjected to aging for a long period to produce basic magnesium carbonate. Magnesium sulfate heptahydrate
(12.5 g) is mixed with 100 g of water at 85 ° C to give an aqueous magnesium sulfate heptahydrate solution. Anhydrous sodium carbonate (20 g) is mixed with 100 g of water at 85 ° C to give an aqueous solution of anhydrous magnesium carbonate, which is then added to the magnesium sulfate heptahydrate solution. While maintaining the temperature of the mixture at 85 ° C, the mixture is stirred for 1 hour to proceed the reaction. After completion of the reaction, the solid is filtered and washed to obtain the product, which is then dried to provide basic magnesium carbonate. The basic magnesium carbonate obtained by the reaction is pulverized several times by means
of a hammer mill or a jet mill in order to adjust the particle size as desired. The basic magnesium carbonate finally- obtained is aggregated particles comprising primary particles of flake shape having 0.01-0.2 μm of thickness and 0.1-2 μm of diameter. Mean particle size of the aggregated particle is 0.5-15 μm, with amorphous shape.
The process for coating the basic magnesium carbonate may ¬ be carried out in a dry mode or a wet mode . According to the dry coating process, 3 parts by weight of stearic acid is stirred with 100 parts by weight of basic magnesium carbonate in a super mixer under the condition of 110 ° C and 500 rpm for 20 minutes to provide basic magnesium carbonate coated with stearic acid. According to the wet coating process, 600 parts by weight of water is added to 100 parts by weight of basic magnesium carbonate, and the mixture is stirred thoroughly, and then 3 parts by weight of stearic acid dissolved in ethanol is added thereto and the resultant mixture is reacted with stirring at 90 ° C for 30 minutes. After the reaction is completed, the reaction mixture is filtered and dried by heating at 150 ° C to produce basic magnesium carbonate coated with stearic acid.
The amount of the coating agent employed is 0.1-20 parts by weight, more preferably 1-10 parts by weight on the basis of the weight of basic magnesium carbonate.
The basic magnesium carbonate according to the present invention is represented by Chemical Formula 1:
M 2+ x (A n -) y M 2+ (OH) z -mH 2 O (1) wherein, M 2+ is Mg 2+ or Ca 2+ , A n~ is CO 3 2" , x is 1-5, y is 1-5, z is 0-2, and m is 0-5.
More specifically, the basic magnesium carbonate can be represented by one of Chemical Formulas 2 to 6. Particularly, hydromagnesite, dihydromagnesite, magnesite or the like may be used.
Mg 4 (COa) 4 Mg (OH) 2 -4H 2 O (2)
Mg 3 (CO 3 J 3 Mg (OH) 2 -3H 2 O (3)
Mg 4 (CO 3 J 4 Mg(OH) 2 (4)
Mg 3 (CO 3 J 3 Mg(OH) 2 (5)
MgCO 3 (6) The mean particle size of the basic inorganic substance employed according to the invention is not more than 10 μm, more preferably not more than 3 μm. If the particle size is more than 10 μm, more milling process is performed during the preparation of the additive slurry to increase the thermal hysteresis that is given to the chlorine resistant material.
When the additive to which much thermal hysteresis has been given is employed, color of the final product converts to grey
(lower a value) to deteriorate the quality of the product, and additional loss of energy occurs in view of economy. In addition, since the breakage of fiber increases during spinning, the size of the inorganic particle employed should be 10 μm or less, preferably 3 μm or less for continuity of
spinning and production stability, being advantageous of application to the process.
Secondary aggregation of the basic inorganic substance used as a chlorine resistant material occurs in a polar solvent used in preparing a polyurethaneurea elastic fiber such as N,N-dimethylacetamide, N,N-dimethylformamide, to induce raise of filter pressure during the spinning process and breakage of fibers. Thus, the surface of the basic magnesium carbonate employed in the present invention is coated with acidic or basic coating agent to adjust the pH of the chlorine resistant material to weakly basic to neutral pH of 7-9, so that the basicity and charge of the surface of the material can be lowered to reduce the occurrence of secondary aggregation. In addition, moisture absorption during the storage or exposure to open air of the material is prevented to solve the problems of gel formation in the dope, pressure rise and generation of breakage of fiber during the spinning process, as well as inhibiting coloring or discoloring of the fiber after spinning. The activity of the chlorine resistant additive according to the invention can be increased by thermal treatment. The activity can be increased by removing the surface water or crystal water partly via thermal treatment at 300 ° C or less, or completely via thermal treatment at 400 ° C or more.
As the coating agent which can be employed in the chlorine resistant material according to the present invention, one or more substance (s) selected from fatty acids, fatty acid metal salts, fatty acid esters, fatty acid phosphoric esters, silica, silane, polyorganosiloxanes, and polyorganosiloxane/polyorganohydrogensiloxane mixtures may be coated in an amount of 1-20 parts by weight of basic magnesium carbonate via dry or wet process.
More specifically, the coating agent may be selected from higher fatty acids such as stearic acid, oleic acid, palmitic acid and lauric acid; higher alcohols such as stearyl alcohol, oleyl alcohol and laury alcohol; fatty acid esters such as glyceryl monostearate, stearyl oleate, lauryl oleate; fatty acid metal salts such as sodium stearate, magnesium stearate, calcium stearate, sodium oleate, sodium palmitate, sodium laurate, sodium laurylsulfonate,- fatty acid phosphoric esters such as stearyl phosphate, oleyl phosphate, lauryl phosphate, tridecyl phosphate, butyl phosphate having C 4 ^ 30 straight or branched alkyl group; silicas such as calcium silicate (Water- glass No.3 from DC Chemical Co., Ltd.); silanes such as the compound represented by chemical formula (RO) 3 SiR" (R' or R" represents same or different Ci_ 40 aliphatic or aromatic hydrocarbon) ; polyorganosiloxanes such as polydimethylsiloxane,- and polyorganohydrogensiloxanes such as
polydimethylhydrogensiloxane .
The coating of the material can be performed in a dry or a wet mode. According to the wet mode, the coating agent is added as a liquid or an emulsion to the slurry of basic magnesium carbonate particles, and the mixture is sufficiently mixed and dried. According to the dry mode, the coating agent is added as a liquid, emulsion or solid phase, while sufficiently stirring the basic magnesium carbonate particles by using a mixer such as super mixer and Henschel mixer, and the resultant mixture is fully mixed under heating or without heating.
The chlorine resistant material according to the present invention may be treated by coating or encapsulation to improve the moisture resistance and dispersiveness . In general, coating means a process of attaching an organic or an inorganic coating agent to only parts of the surface of chlorine resistant material, while encapsulation means a process of attaching an inorganic coating agent to entire surface of chlorine resistant material. On the surface of the capsule, minute holes of nano-size are distributed so that chlorine resistant agent inside can react with active chlorine. When encapsulation coating is made on a chlorine resistant material, the problem of eluting of chlorine resistant material into acidic salt bath under acidic dyeing at pH 3-4
can be overcome .
When the basic magnesium carbonate is used without coating in the present invention, the material is liable to absorb moisture. Thus, careful moisture control is required from the packing stage of the product to the use of the moisture-resistant package after storage in a storehouse. If an apparatus for drying the material is incorporated at the final usage, it may be utilized without coating. Another method to prevent moisture absorption is to disperse a chlorine resistant material in DMAc solvent in advance to prepare a slurry and stored in a drum, the slurry is then directly introduced to a tank for preparing additive slurry in the field. However, when the material is used without coating, the problems of second aggregation owing to surface charge of the chlorine resistant material, of inconvenience of handling the material and of cost for moisture management occur, so that it is preferable to coat the chlorine resistant material with the coating agent according to the present invention.
In the present invention, the moisture management of the basic magnesium carbonate as a chlorine resistant additive is very important. Owing to moisture absorbed by the chlorine resistant material, gel formation or poor dispersion occurs in the second polymer to cause problems of raising the filter pressure during the process and increasing breakage of fiber.
When the chlorine resistant material is coated with less than 1 part by weight of coating agent, sufficient moisture prevention or sufficient dispersive effect during the preparation of slurry cannot be expected. On the other hand, if it is more than 20 parts by weight, no more enhancement of dispersing effect of the chlorine resistant material occurs as compared to the material coated with not more than 20 parts by weight of the coating agent. Even in terms of economy, the coating agent is preferably used in an amount of l~20 parts by weight.
According to the invention, the basic magnesium carbonate to which fatty acid or silane type coating agent is attached is added in an amount of 0.1-10% by weight of total dope solution. If the amount is less than 0.1% by weight, chlorine resistant property cannot reach the expected value. On the other hand, if it is more than 10% by weight, the chlorine resistant performance increases but mechanical properties such as strength, elongation and modulus of the fiber decreases. Thus, the above range is most preferable. The coated basic magnesium carbonate to be added is preferably dispersed in N,N-dimethylacetamide solvent and pulverized and dispersed by using a wet pulverizer to make the size of 40 μm or less, more preferably 20 μm or less before use.
In order to confirm pulverization and dispersion of the
additive slurry in the present invention, filterability of the additive slurry is measured. Additive slurry (1.5 kg), that is pulverized and dispersed by using a wet pulverizer, is passed through a filter having 25 mm of diameter and 20 μm of pore size under a pressure of 3 kg/cm 2 . The standard for controlling the pulverized and dispersed slurry is whether the amount of the slurry passed through is at least 85% of the amount introduced. The weight of the slurry passed through the filter is an important index of operation continuity in the process for spinning a polyurethaneurea elastic fiber. Thus, the more slurry is passed through, the better the operation continuity is during the dry spinning.
According to the present invention, hydromagnesite with fatty acid attached is prepared by pulverizing and dispersing an additive slurry comprised of the conventional additives used in polyurethaneurea elastic fiber such as titanium dioxide, a gas stabilizer, a light stabilizer, an anti-oxidant, spinning ability enhancer and N,N-dimethylacetamide solvent, by using a high performance wet pulverizer to provide 10 μm of the particle size of inorganic additive in the slurry, preferably not more than 3 μm of mean particle size. It is then added to a dope and spun by dry spinning process to prepare a polyurethaneurea chlorine resistant elastic fiber.
Now, the process for preparing the composition according
to the invention is specifically described.
Polytetramethylene ether glycol (PTMEG, Molecular weight 1815) and diphenylmethane-4 , 4 ' -diisocyanate (MDI) are introduced in a molar ratio of 1.70 (NCO/OU=I .70) and polymerized to prepare a first polymer having not more than 3.0 mol% of unreacted diisocyanate at the terminal. The first polymer is uniformly dissolved in N,N-dimethylacetamide (DMAc) to give a first polymer mixture in which the content of unreacted diisocyanate has been certainly adjusted. Ethylene diamine and 1, 2-diaminopropane as the chain extender and diethylamine as the chain terminator are dissolved in N, N- dimethylacetamide, and the mixture is introduced with the first polymer mixture to a second polymerizer to obtain a second polymer (35% by weight) . To the second polymer, added is a slurry having not more than 10% by weight of solid content, which is comprised of titanium dioxide, a gas stabilizer, an anti-oxidant, a dyeability enhancer, magnesium stearate and hydromagnesite (4% by weight) and N, N- dimethylacetamide solvent. The slurry is incorporated to the process after a pulverizing and dispersing stage by using a wet pulverizing device to provide a particle size of the inorganic additives in the slurry of 10 μm or less. The spin dope is passed through a static mixer of pipe shape to homogeneously mix the additive slurry with the second polymer,
then the dope is spun at a temperature of 240~255 ° C immediately downstream the spinning nozzle with 700-1200 m/min of spin rate in a dry spinning mode to prepare a polyurethaneurea chlorine resistant fiber. After spinning, the residual solvent content in the spandex fiber is adjusted to 1.0% by weight or less. The inherent viscosity was 1.25 when measured in a solution in N,N-dimethylacetamide (0.5 g/100 ml)
[Advantageous Effects] The polyurethaneurea chlorine resistant fiber prepared as described above has excellent uniformity and spinning ability, and provides excellent quality of cloth material having good elastic resilience, strength retention and chlorine resistant property after dyeing process. Said chlorine resistant polyurethaneurea elastic fiber is also included in the scope of the invention.
[Mode for invention]
Prior to the description of the Examples of the present invention, various methods of evaluation are described:
1) Measuring viscosity of a polymer
Viscosity of a polymer with chain extension and chain termination having been completed is measured at 40 ° C by using
a Brookfield Viscometer (B type), and reported in poise.
2) Measuring inherent viscosity
Inherent viscosity of a solution prepared by dissolving
0.5 g of a polymer in 100 ml of N,N-dimethylacetamide is measured by Ubbelohde viscometer in a constant temperature chamber at 30+0.5 ° C, to obtain the inherent viscosity of the polymer.
3) Measuring pH of the chlorine resistant material
Two grams of sample is dispersed in 25 ml of ethyl alcohol, and pH of the material is measured by using a pH electrode. The pH of the material is controlled to be 7-9.
4) Tensile strength, Tensile elongation
By using a tensile tester (manufactured by Instrong, UTM) , a sample having 5 cm length is stretched at a speed of 50 cm/min under the condition of 25 ° C, 65% RH to measure Tensile strength (g/d) and Tensile elongation (%) .
5) Wet-heat elastic resilience
A 10 cm interval of a sample is marked, and the sample is stretched by 100%. After treating the sample under steam atmosphere at 130°C for 60 minutes, the stretch is released, and the length recovered (Lw) is measured. The resilience is expressed in a ratio to the untreated length of the sample. The high resilience represents high heat resistance but low thermal setting.
Moisture-heat elastic resilience = [(20-Lw) /10] x 100
6) Dry-heat strength retention
A sample is treated with hot air at 180 ° C for 1 minute while it is stretched by 100%, and measured its strength in a tensile tester. The ratio of the strength after the dry-heat treatment to the strength of untreated fiber is the strength retention. The higher the strength retention is, the higher the heat resistance is.
7) Chlorine resistant property of fiber A sample under 50% of stretching is impregnated in a bath having 20 ppm of effective chlorine concentration (pH 7) , and the ratios of the strength after 24, 48 and 72 hours are determined respectively as the strength retention. The higher the strength retention is, the higher the chlorine resistant property is. The sample length before and after the chlorine treatment are measured to determine the elastic resilience. The higher the resilience is, the higher the chlorine resistant property is. (Criteria of fiber for chlorine resistance property: at least 70% of strength retention after 48 hr treatment)
8) Chlorine resistant property of cloth material
The cloth material is cut along warp direction to give a test piece of 2cm x 20cm. While being stretched by 50%, the test piece is impregnated in a bath having 200 ppm of
effective chlorine concentration (pH 7) at 25 ° C . The ratio of 50% stretch strength over time is determined as the strength retention. The higher the retention is, the higher the chlorine resistant property is. 9) Measuring number of polymer gel particles
In an electrolyte solution of 1% LiCl/DMAc, 0.5% of a polymer is dissolved, and the number of gels existing in the polymer is measured by using a Coulter Counter (Beckman) .
10) Measuring spinning ability Spinning is processed for 24 hours, and the number of occurrence of breakage of fiber is shown as the proportion based on total number of winding.
11) Measuring color of raw fiber
By using a Spectrophotometer (Minolta CM-508D) , a surface of spandex package is measured three times to obtain L/a/b value of the raw fiber.
12) Measuring filterability of additive slurry Additive slurry (1.5 kg) pulverized and dispersed by a wet pulverizer is passed through a filter having 25 mm of diameter and 20 μm of pore size under a pressure of 3 kg/cm 2 . When the amount of the slurry passed through is at least 85% of the amount introduced, the slurry is fed into the process.
Examples
Now the present invention is specifically described by- means of Examples, but the invention is not restricted to those Examples by any means . [Example 1]
Polytetramethylene ether glycol (PTMEG, MW 1815) and diphenylmethane-4, 4' -diisocyanate (MDI) were introduced in a molar ratio of 1.70 (NCO/OH=1.70) and polymerized to prepare a first polymer having not more than 3.0 mol% of unreacted diisocyanate at the terminal. The first polymer was uniformly dissolved in N,N-dimethylacetamide (DMAc) in a high performance dissolver to give a first polymer mixture in which the content of unreacted diisocyanate has been constantly adjusted to 2.64+0.02 mol%. Ethylene diamine and 1,2- propylenediamine as the chain extender and diethylamine as the chain terminator were dissolved in DMAc, and the mixture is introduced with the first polymer mixture to a second polymerizer. Via conventional polymerization process of polyurethaneurea elastic fiber, a polymer having about 35% of solid content and about 2000-3500 poise of apparent viscosity at 40 ° C. Inherent viscosity of the polymer measured in a solution in N,N-dimethylacetamide (0.5 g/100 ml) was 1.0.
To the polyurethaneurea second polymer polymerized with the chain extender and the chain terminator, following
additives were added in order for the usual spandex to have durability while washing and using and maintain white color, to improve color-change resistance (prevent yellowing) and dyeability, to prevent or reduce deterioration of mechanical property and to enhance the durability against chlorine (the amount is based on total weight of the spun spandex fiber) : 0.50% by weight of titanium dioxide; 0.50% by weight of 1,1,1' ,1' -tetramethyl-4,4' - (methylene-di-p-phenylene) disemicarbazide as a waste gas stabilizer (HN-150, from Nippon Hydrazine); 1.44% by weight of a hindered phenolic compound, 1,3, 5-tris (4-t-butyl-3-hydroxy-2, 6-dimethylbenzene) -1,3,5- triazine-2,4,6- (1H,3H,5H) -trione [CYANOX 1790 ® (from Cytec, United States)] as an anti-oxidant ; 0.30% by weight of magnesium stearate (Nippon Oil and Fats, Japan) in order to improve the stickiness and unwinding ability; 0.51% by weight of poly (N,N-diethyl-2-aminoethyl methacrylate) as a dyeability enhancer; and 4.0% by weight of hydromagnesite (from Nanotech Ceramics, Airlite-Sl) coated via dry mode with 3 parts by weight of stearic acid as a chlorine resistant additive. When preparing the additive slurry, inorganic substances were pulverized and dispersed by using a wet pulverizer to make the particle size not more than 10 μm. A wet pulverizer was used to pulverize the inorganic additives among the additive slurry, to make the mean particle size of the inorganic substances not
more than 10 μm. Then, after performing a filter test of the slurry by using a 20 μm filter, the slurry was introduced to the process. At this time, homogeneous mixing of the final polymer with the additives is important, so that a static mixer having a cylindrical pipe shape was employed for homogeneous mixing of the additives with the final polymer. The polyurethaneurea product thus prepared contained about 35% of solid, being a polymer solution having 4350 poise (40 ° C) of viscosity, which is suitable for spinning. The additive slurry to be mixed with the final polymer was maintained at 45 ° C. The polymer solution for spinning thus prepared was subjected to dry spinning wherein the solution was constantly pumped by a gear pump to a spinning can having the atmosphere at 250 ° C to evaporate the solvent, at a spinning rate of 900 m/min. The physical properties are shown in Table 2.
[Example 2]
An elastic fiber was prepared according to the same procedure described in Example 1, but using hydromagnesite having mean particle size of not more than 10 μm (Airlite-S3 from Nanotech Ceramics) coated via wet mode with stearic acid as the chlorine resistant material . [Example 3] An elastic fiber was prepared according to the same
procedure described in Example 1, but using non-coated hydromagnesite having mean particle size of not more than 10 μm (Airlite-S3 from Nanotech Ceramics) as the chlorine resistant material. [Example 4]
An elastic fiber was prepared according to the same procedure described in Example 1, but using 2% by weight of hydromagnesite (Airlite-Sl, from Nanotech Ceramics) .
[Comparative Example 1] An elastic fiber was prepared according to the same procedure described in Example 1, but without adding a chlorine resistant material. [Comparative Example 2]
An elastic fiber was prepared according to the same procedure described in Example 1, but hydrotalcite (DHT-4A, from Nippon Kyowa) was used instead of hydromagnesite in an amount of 4% by weight.
[Comparative Example 3]
An elastic fiber was prepared according to the same procedure described in Example 1, but magnesium hydroxide was used instead of hydromagnesite in an amount of 4% by weight.
[Table 1]
[Table 2 ]
Note: b value: Yellowing is observed when it is 7 or more.
From the Examples and Comparative Examples, it is found that the elastic fiber according to the process of the invention exhibits very excellent chlorine resistant property and spinning ability.
[industrial Applicability]
The polyurethaneurea elastic fiber prepared according to the present invention has excellent chlorine resistant
property and spinning ability, and provides, after dyeing process, a cloth material having excellent chlorine resistant property, elastic resilience and strength retention.