HK1094219A - Spandex having low heat-set temperature and materials for their production - Google Patents

Description

Elastic fiber having low heat-set temperature and material for its production

Technical Field

The present invention relates to segmented polyurethane/ureas and elastic fibers made therefrom having excellent heat-set efficiency, elasticity, and mechanical properties, and to materials and methods for producing such polyurethane/ureas and fibers. More particularly, the present invention relates to polyurethane/ureas and elastic fibers made from isocyanate terminated prepolymers derived from a mixture of polytetramethylene ether glycol (PTMEG) and a low unsaturated high molecular weight polyoxyalkylene glycol, the prepolymers being chain extended with a chain extender component comprising specified amounts of a linear diamine and at least one asymmetric aliphatic and/or cycloaliphatic diamine.

Background

Polyurethane/ureas in the form of fibers and films having elastomeric properties have found wide acceptance in the textile industry. The term "spandex" is commonly used to describe these elastomeric polyurethanes/ureas and refers to long chain synthetic polymers composed of at least 85 weight percent segmented polyurethane. The term "elastomer" (e.g. in europe) is also used to describe these polymers.

The polymers used in the production of elastic fibers are generally prepared by forming a prepolymer between a polymeric diol and a diisocyanate and then reacting the resulting prepolymer with a diamine in a solvent. This prepolymer is sometimes referred to as a "capped glycol". The resulting polymer chain may then be extended by further reaction with one or more chain extenders. The chain may then be terminated by the addition of a chain terminator. The chain terminator may be mixed with the chain extender or may be added separately after the chain extender.

Elastic fibers are typically prepared by reaction spinning, melt spinning, dry spinning or wet spinning a polyurethane solution into a column filled with a hot inert gas such as air, nitrogen or water vapor, or into an aqueous bath to remove the solvent, followed by winding the fiber. Dry spinning is a process of forcing a polymer solution through a spinneret orifice into a shaft to form filaments. Heated inert gas is passed through the chamber to evaporate solvent from the filaments as they pass through the shaft. The resulting elastomeric fiber can then be wound onto a cylindrical core to form an elastomeric fiber supply package.

Because of their good elasticity and tensile strength, elastic fibers have been used in the production of articles of clothing, disposable personal care products, upholstery, and other commercial and industrial products. The elastic fibers may be blended with other natural and/or synthetic fibers and/or yarns.

Elastic fibres are used in many different applications in the textile industry, in particular in underwear, tight-fitting (form-fit) garments, bathrobes and elastic garments or socks. The elastic fiber provided can be a core spun elastomeric yarn spun from filaments or a staple fiber yarn, or a staple fiber blended with a non-elastic fiber to improve the wearability of a fabric that is not inherently elastic.

The preferred polymeric glycol commercially used to produce elastic fibers is polytetramethylene ether glycol (PTMEG). PTMEG is solid at room temperature and produces prepolymers, particularly diphenylmethane diisocyanate ("MDI") prepolymers, which have extremely high viscosities.

However, despite the inherent difficulties in handling PTMEG, its high cost, and the unsatisfactory hysteresis of fibers made from PTMEG, PTMEG remains the mainstay of elastic fiber production, as no satisfactory alternative has been found to date.

One potential alternative to PTMEG that has been evaluated is polyoxypropylene glycol ("PPG"), which is in principle useful for making elastic fibers. The preparation of elastic fibers from prepolymers made from a polyol component consisting essentially of PPG is economically attractive because the cost of PPG is significantly lower than that of PTMEG. In addition, fibers made from prepolymers made with PPG exhibit excellent elongation and retraction or retention. PPGs themselves are easier to handle than PTMEG because they are non-crystallizable, lower viscosity liquids with low pour points.

For example, U.S. Pat. No. 3,180,854 discloses a polyurethane/urea fiber based on a prepolymer made with a 2000Da molecular weight polyoxypropylene diol. However, polypropylene oxide-derived elastic fibers generally do not perform as well as PTMEG-based fibers. Therefore, polyoxypropylene diols have not been commercially used for elastic fiber production.

High molecular weight polyoxypropylene diols made by conventional methods contain a high percentage of terminally unsaturated or monofunctional hydroxyl-containing materials ("monols"). Many believe that the monols act as chain terminators, limiting the formation of the desired high molecular weight polymer during chain growth, and producing products that are generally inferior to PTMEG derived elastomers.

Unsaturation is measured according to ASTM D-2849-69 "test polyurethane foam Polyol Raw Materials" and expressed as milliequivalents of unsaturation per gram of Polyol (meq/g).

The reduction of unsaturation and the accompanying large monol fraction in polyoxypropylene polyols has been described as a way to produce polyurethane elastomers with improved properties. For example, the use of polyols having a low content of monofunctional species as a means of increasing the molecular weight of the polymer has been disclosed; it is also mentioned that increasing the molecular weight of the polymer is desirable in producing higher performing polymers.

U.S. patent 5,340,902 discloses that unsaturation levels of less than 0.03meq/g are beneficial in the production of elastic fibers, but does not provide any examples to illustrate the use of unsaturation levels of less than 0.03meq/g in the production of elastic fibers. U.S. patent 5,691,441 discloses that low monol polyol blends having unsaturation levels less than 0.010meq/g are required to obtain the advantages of the disclosed invention.

U.S. patent 5,691,441 teaches that "ultra low unsaturation polyols have been found to differ in number from conventional polyols and low unsaturation polyols". In view of this teaching, it is expected that elastic fibers made from blends of PTMEG and polyoxypropylene diols having higher levels of unsaturation (greater than 0.010meq/g) will have fibers that are significantly inferior to fibers based on PTMEG and blends comprising polypropylene diols having ultra-low levels of unsaturation (i.e., less than 0.010 meq/g). U.S. patent 5,691,441 also teaches that "ethylene diamine is particularly preferred as the sole chain extender".

Elastic fibers and fabrics and garments comprising elastic fibers are typically heat-set to provide a fiber or fabric with good dimensional stability and formed into a garment. However, heat setting has disadvantages. Heat setting is an additional cost to complete the weaving of elastic fabrics containing elastic fibers. In addition, typical elastic fiber heat-setting temperatures can adversely affect sensitive companion yarns such as wool, cotton, polypropylene, and silk, requiring more expensive processing. In addition, heat-sensitive yarns such as those from polyacrylonitrile, wool, and acetate cannot be used in the elastic fiber heat-setting step because high heat-setting temperatures will adversely affect such heat-sensitive yarns.

Elastic fibers with low heat-set efficiency require long times and high temperatures for heat-setting. It is desirable that fabrics comprising cotton, wool, polypropylene and silk be heat set at lower temperatures than fabrics based on synthetics such as nylon or polyester. It is generally desirable to heat-set fabrics comprising cotton and elastic fibers, but if the elastic fibers have adequate heat-setting efficiency only at the temperatures used for fabrics comprising nylon, the fabrics cannot be properly and effectively heat-set.

Various methods have been used to improve the heat-set efficiency of elastic fibers and thereby reduce the temperature at which the elastic fibers can be heat-set. For example, U.S. Pat. No. 5,539,037 discloses the use of low concentrations of alkali metal carboxylates and thiocyanates in elastic fibers to increase their heat-set efficiency. However, the salt is prone to dissolution during fabric processing, thereby reducing its effectiveness.

U.S. patent 6,403,682B 1 describes elastic fibers having improved heat-set efficiency, wherein the elastic fibers contain quaternary amine additives. However, all reported heat-set tests were done at 190 ℃, which is well above the temperature at which elastic fibers containing cotton yarns can be heat-set without damage to the cotton fibers.

U.S. Pat. No. 5,981,686 discloses the use of high proportions of 1, 3-diaminopentane (1, 3-DAP) chain extenders to increase heat-set efficiency.

U.S. Pat. Nos. 5,000,899 and 5,948,875 disclose the use of a high percentage of 2-methyl-1, 5-pentanediamine to increase elastic fiber heat-set efficiency.

None of these patents disclose the use of blends of these co-chain extenders with polytetramethylene ether glycol and ultra low unsaturation polypropylene glycol. Furthermore, in some cases, excess amounts of co-chain extender result in excessive tackiness, making smooth release from the bobbin difficult. Too high a level of co-chain extender may also reduce the chemical resistance of the fibers to alcohols, dyes, bleaches, and other chemicals that may be encountered during the production of fabrics and fixing operations.

The preparation of various types of mixtures of diamines for use in the chain extension step in elastomeric fiber polymers is known in the art.

Of these, Frazer et al in U.S. patent 2,929,803, Wittbecker in U.S. patent 3,507,834, McMillin et al in U.S. patent 3,549,596, Lawrey et al in U.S. patent 6,737,497 each disclose chain extender mixtures that can be used in making elastic fibers. In U.S. Pat. No. 4,973,647, Bretches et al disclose the use of 15-32 mol% 2-methyl-1, 5-pentanediamine as a co-chain extender in the preparation of elastic fibers containing PTMEG.

Us patent 6,472,494B 2 discloses the use of a mixture of 2,4 '-MDI and 4, 4' -MDI for making elastic fibers with high heat-set efficiency. However, 2, 4' -MDI is not commercially available in pure form. The high MDI grades in the 2,4 'isomers also tend to be much higher in color than the pure 4, 4' MDI.

In U.S. Pat. No. 6,639,041B 2 Nishikawa et al disclose an elastic fiber based on a copolymer (alkylene ether) comprising certain proportions of tetramethylene ether and or ethylene ether or 1, 2-propylene ether moieties. These copolyethers are considered even more expensive than standard polytetramethylene ether glycols, which are themselves significantly more expensive than polyoxypropylene glycols.

Accordingly, there remains a need in the art for new and improved polyether-based elastic fiber yarns that, in addition to their known advantageous properties, can be effectively heat-set at lower temperatures while providing a desirable balance of other physical properties.

Disclosure of Invention

It is an object of the present invention to provide polyurethane/ureas for producing elastic fibers which are made from large amounts of PPG and which have good heat-setting efficiency.

It is another object of the present invention to provide polyurethane/ureas and elastic fibers made therefrom that are based in part on less expensive and more easily handled polyoxypropylene diols and that exhibit improved heat-set characteristics compared to elastic fibers made solely from PTMG.

It is yet another object of the present invention to provide elastic fibers and methods of making elastic fibers that are characterized by excellent toughness, elongation, retractive ability, and set.

These and other objects, which will be apparent to those skilled in the art, are achieved by chain extending an isocyanate-terminated prepolymer produced from an isocyanate-reactive component which meets specified criteria with a chain extender component comprising: (1) greater than 25 to 75 equivalent percent (based on the total equivalents of the chain extender component) of an asymmetric aliphatic and/or cycloaliphatic diamine and (2) a linear diamine such as ethylene diamine. The isocyanate-reactive component comprises: (1) at least one PTMEG and (2) at least one polyoxypropylene diol, having a molecular weight greater than about 1500Da and an unsaturation level less than 0.03 meq/g. The elastomer thus obtained is then spun into fibers.

Detailed Description

This invention relates to polyurethane/ureas suitable for use in the production of elastic fibers, elastic fibers produced from these polyurethane/ureas, and methods of producing the polyurethane/ureas and elastic fibers.

The polyurethane/ureas of the invention are prepared from isocyanate-terminated prepolymers. Suitable prepolymers are produced by reacting an isocyanate-reactive component, which is typically comprised of a diol, with an excess of a diisocyanate. Isocyanate-terminated prepolymers are commonly used to produce such elastomers having a relatively low isocyanate content. The isocyanate content is preferably from about 2.25 to about 4.0%. It is particularly preferred that the isocyanate content of the prepolymer is from 2.5 to 3.75%. The prepolymer is then chain extended in solution.

A key feature of the present invention is the chain extension of the isocyanate terminated prepolymer using a chain extender component, wherein the chain extender component comprises at least one asymmetric aliphatic and/or cycloaliphatic diamine and at least one linear diamine. The aliphatic and/or cycloaliphatic diamine should be present in an amount of greater than 25 to about 75 equivalent percent, preferably from about 30 to about 70 equivalent percent, and most preferably from about 35 to about 65 equivalent percent, based on the total equivalents of the chain extender component. The linear diamine is generally used in an amount of about 25 to about 75 equivalent percent (based on the total equivalents of the chain extender component), preferably about 30 to about 70 equivalent percent, and most preferably about 35 to about 65 equivalent percent.

Examples of suitable asymmetric aliphatic and/or cycloaliphatic chain extenders include: isophorone diamine, 1, 2-diaminopropane; methyl-1, 3-diaminocyclohexane; 1, 3-diaminocyclohexane; 2-methylpentamethylene diamine (commercially available from DuPont under the name Dytek A); 1, 4-diamino-2-methylpiperazine; 1, 4-diamino-2, 5-dimethylpiperazine; and methyl dipropylamine.

Examples of suitable linear amine chain extenders include: ethylene diamine; hydrazine; 1, 3-propanediamine; and tetramethylenediamine. Ethylene diamine is most preferred.

Any known aliphatic and/or aromatic diisocyanate can be used to produce the isocyanate-terminated prepolymer used in the present invention. Preferred isocyanates include: linear aliphatic isocyanates such as 1, 2-ethylene diisocyanate, 1, 3-propylene diisocyanate, 1, 4-butylene diisocyanate, 1, 6-hexylene diisocyanate, 1, 8-octylene diisocyanate, 1, 5-diisocyanato-2, 2, 4-trimethylpentane, 3-oxo-1, 5-pentane diisocyanate and the like; cycloaliphatic diisocyanates such as isophorone diisocyanate, cyclohexane diisocyanate, preferably 1, 4-cyclohexane diisocyanate, fully hydrogenated aromatic diisocyanates such as hydrogenated tetramethylxylylene diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated methylenediphenylene diisocyanate; and aromatic diisocyanates such as toluene diisocyanate, particularly 2, 4-isomer, methylene diphenylene diisocyanate, particularly 4, 4 '-methylene diphenylene diisocyanate (4, 4' -MDI), tetramethylxylylene diisocyanate and the like. 4, 4' -MDI is particularly preferred.

The isocyanate-reactive component used to prepare the isocyanate-terminated prepolymer comprises: (1) copolymers of at least one high molecular weight, low unsaturation polyoxypropylene polyol and (2) at least one PTMEG or tetrahydrofuran ("THF") and 3-methyltetrahydrofuran ("3-MeTHF"). The hydroxyl-terminated copolyethers used as (2) in the isocyanate-reactive component typically contain 4 to 20 mol% 3-MeTHF and have a molecular weight of from about 650 to about 4,500 (preferably from about 2,400 to about 3,800).

The high molecular weight polyoxypropylene polyol component used in the present invention must have an unsaturation level of less than or equal to 0.03 meq/g. The polyoxypropylene polyol component used to produce the isocyanate-terminated prepolymer should include at least 70 weight percent of the low unsaturation polyoxypropylene polyol, based on the total weight of the high molecular weight polyoxypropylene polyol component. Most preferably, the total amount of high molecular weight polyoxyalkylene polyol present in the polyol component has an unsaturation level of less than 0.03meq/g, more preferably less than 0.02meq/g, most preferably less than 0.015 meq/g. However, it is within the scope of the present invention to include a minor proportion of a high molecular weight polyoxypropylene polyol having a somewhat higher level of unsaturation in the polyol component, for example up to about 30 weight percent of the polyoxypropylene polyol has an unsaturation of about 0.06 meq/g. Under such circumstances, the actual unsaturation of the high molecular weight polyoxypropylene polyol component should still be about 0.03meq/g or less. However, as long as 70% by weight or more of the high molecular weight polyoxypropylene polyol component is a low unsaturation polyoxypropylene diol, the beneficial results of the present invention can be obtained.

The term "low unsaturation polyoxypropylene diol" as used herein refers to a polymeric diol prepared by oxypropylating a dihydroxy initiator with propylene oxide in the presence of a catalyst in a manner such that the total unsaturation of the polyol product is less than 0.03 meq/g.

The polyoxypropylene diol may contain oxyethylene moieties in random distribution or in block form. If the block contains ethylene oxide moieties, the block is preferably a terminal block. However, it is preferred when randomly distributed ethylene oxide moieties are present. Generally, the polyoxypropylene diol should contain up to about 30 weight percent oxyethylene moieties, preferably up to 20 percent, more preferably up to about 10 percent. The polyoxypropylene diols may also contain higher alkylene oxide moieties such as those derived from 1, 2-and 2, 3-butylene oxide and other higher alkylene oxides or oxetanes (oxetanes). Such higher alkylene oxide may be 10 to 30 weight percent of the polyoxypropylene polyol. However, it is preferred that the polyoxypropylene polyol is derived substantially from propylene oxide or a mixture of propylene oxide with a lesser amount of ethylene oxide. Such total diols comprising a major portion of the propylene oxide fraction are considered to be the term polyoxypropylene diols as used herein.

It has been surprisingly found that if the present chain extender component is used, an elastomeric fiber system based on an isocyanate reactive component that is a blend of PPG and PTMEG produces a fiber with acceptable mechanical properties even though the PPG component has a level of unsaturation as high as 0.030 meq/g. Contrary to the teachings of the prior art, if a chain extender component comprising from greater than 25 to about 75 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine and a linear diamine (e.g., ethylene diamine) is used, elastic fibers having excellent mechanical properties are obtained even if a PPG component having a level of unsaturation greater than 0.010meq/g is used.

The high molecular weight, low unsaturation polyoxypropylene diols useful in the practice of the present invention generally have molecular weights of at least about 1500Da, preferably at least about 2000Da, and may range up to 8,000 Da or more. Particularly preferred molecular weights are from about 1600 Da to about 4000 Da, most preferably from about 1800 Da to about 3000 Da.

As used herein, "molecular weight" and "equivalent weight" are expressed in Da (daltons) and are number average molecular weight and number average equivalent weight, respectively, unless otherwise indicated.

The number average molecular weight of each polyether diol was determined from the number of hydroxyl groups of the polyether diol, which were measured by the imidazole-pyridine catalyst method described by S.L. Wellon et al in "Determination of hydroxyl Content of Polyurethane polyol and Other Alcohols", ANALYTICALCHEMISTRY, Vol.52, No.8, 1374-1376 (1980, 7 months).

Of course, blends of more than one high molecular weight polyoxypropylene diol may be used, or small amounts, i.e., up to 10 weight percent, of low molecular weight diols may be added. However, when such blends are used, the blend average molecular weight of the high molecular weight component should be at least 1500 Da.

Preferably, the prepolymer is prepared from substantially all difunctional polyols, especially those derived from polyoxypropylene diols. The term "polyoxypropylene diol" as used herein comprises a minor amount, i.e., up to about 5 weight percent or more, of triol.

The polytetramethylene ether glycol (PTMEG) used to make the polyurethane/urea elastomers of the present invention has a molecular weight greater than 600Da, preferably from about 600 to about 6,000 Da, and most preferably from about 600 to about 3,000 Da.

PTMEG may be prepared by any known method. One suitable method is to polymerize tetrahydrofuran in the presence of a lewis acid catalyst. Suitable polymerization catalysts include anhydrous aluminum chloride and boron trifluoride etherate. Such catalysts are well known and are the subject of numerous patents and publications. PTMEG polyols are commercially available from a number of sources at a variety of molecular weights. For example, Invista is under the trademark Terathane^*PTMEG polyol is sold. PTMEG polyol is sold by BASF Corporation under the name PolyTHF. Lyondell Chemical Company under the trademark POLYMEG^*Such polyols are sold.

The isocyanate-reactive component, preferably the polyol component used to produce the prepolymer from which the elastic fibers of the present invention are produced, is primarily a diol component, i.e., the diol component is preferably from about 25 to about 75 equivalent percent PTMEG and from about 25 to about 75 equivalent percent polyoxypropylene diol component having an average unsaturation of less than about 0.03meq/g, more preferably from about 35 to about 60 equivalent percent PTMEG and from about 40 to about 65 equivalent percent polyoxypropylene diol component having an average unsaturation of less than about 0.03meq/g, preferably less than about 0.02meq/g, and most preferably less than about 0.015 meq/g.

It should be noted, however, that polyoxypropylene diols having unsaturation levels greater than 0.03meq/g may be included in the polyol component used to produce the prepolymers of the present invention, so long as the overall average unsaturation level of all polyoxyalkylene portions of the polyol component is about 0.03meq/g or less.

The diol components used in the practice of the present invention include: (1) one or more PTMEG glycols, and (2) one or more polyoxyalkylene glycols having an average level of unsaturation in the polyoxyalkylene glycol portion of the glycol component of less than about 0.03 meq/g. The polyol component used to make the prepolymers suitable for use in the practice of the present invention includes the diol component and may also include minor amounts of any other hydroxyl or other reactive species that, when reacted with the isocyanate component, will form an isocyanate-terminated prepolymer with the diol component.

The isocyanate reactive component is reacted with an excess of the desired diisocyanate, preferably under an inert atmosphere or vacuum, at a slightly elevated temperature, i.e., 50 ℃ to 100 ℃, more preferably 60 ℃ to 90 ℃. It is within the scope of the invention to react the diisocyanate with both of the desired diols simultaneously or to first react one diol with the isocyanate and then react the other diol with the diisocyanate. In embodiments of the invention where the prepolymer is formed in a solution of at least 10% dimethylacetamide, lower temperatures can be used to obtain a prepolymer having the desired viscosity. The excess isocyanate is selected so that the% NCO group content in the prepolymer is from about 2.25% to 4.00% by weight, preferably from about 2.5 to 3.75% by weight.

The reaction of the isocyanate with the polyol and any other isocyanate-reactive material may be catalyzed by any known catalyst to promote isocyanate, hydroxyl and/or amino groups: (Such as dibutyltin dilaurate), but the reaction can also be carried out without the use of a catalyst. In a preferred embodiment of the invention, the prepolymer forming mixture includes a catalyst, such as C, which promotes linear polymerization but does not degrade the polymer₆-C₂₀Metal salts of monocarboxylic or naphthenic acids. Particularly preferred catalysts are zinc octoate and calcium octoate.

Generally, the reaction of the polyol and isocyanate components is continued until the isocyanate content becomes constant.

The isocyanate-terminated prepolymer is then dissolved in a solvent, typically a polar aprotic solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, and the like, and then chain extended with the chain extender component of the present invention.

The term "polar aprotic solvent" as used herein refers to a solvent having the property of melting the chain-growth polyurethane at a desired concentration while being substantially unreactive with isocyanate groups.

The polyurethane/urea thus obtained has a hard segment and a soft segment. The terms "soft segment" and "hard segment" refer to a specific portion of the polymer chain. The soft segment is the polyether base portion of a segmented polyurethane/urea polymer derived from PTMEG and polyoxypropylene diol. The hard segments are portions of the polymer chain derived from a diisocyanate and a chain extender. The term "NCO content" refers to the isocyanate group content of the prepolymer prior to chain extension.

Chain terminators are typically included in the reaction mixture to adjust the final molecular weight and, therefore, the intrinsic viscosity of the polyurethane/urea polymer to the desired value. Typically, the chain terminator is a monofunctional compound, such as a secondary amine (e.g., diethylamine or dibutylamine).

After the polymerization reaction is complete, the amount of polyurethane (or polyurethaneurea) in the solution is typically from about 30 to about 50 weight percent; about 31 wt% to about 40 wt%; or about 35 wt% to about 39 wt%; based on the total weight of the solution. The elastic fiber can then be made by reactive spinning, dry spinning, or wet spinning, all of which are known in the art.

Elastic fibers are typically produced by dry spinning. Dry spinning is a process in which a polyurethane/urea polymer solution is forced through a spinneret into a column filled with a hot inert gas such as nitrogen or air to evaporate the solvent and form filaments. The filaments are wound around a cylindrical core to form a supply package of elastomeric fiber.

Processes that are not commonly used to prepare elastic fibers are wet spinning and reaction spinning. In the wet spinning process, a polyurethane/urea polymer solution is pumped through a spinneret into an aqueous bath to remove the solvent prior to winding the fibers. In the reactive spinning process, an isocyanate-terminated prepolymer is extruded through a spinneret into a solvent bath containing a diamine. Chain growth occurs in the bath and fibers are formed and the resulting filaments are wound on bobbins after passing through a drying oven.

In a preferred embodiment of the invention, the elastic fiber is formed by dry spinning from the same solvent as used for the polymerization. For example, the resulting polyurethane may be used to produce elastic fibers that may be wound at speeds of at least 450 meters per minute. In one embodiment of the invention, the speed may be at least 700 meters/minute; or winding the elastic fiber at a speed of at least 800 meters/minute. The product is a high speed spun elastic fiber.

The elastic fibers may be spun as monofilaments or may be fused into multifilament yarns by conventional techniques. Each filament has a textile dtex, for example about 6 to about 25 dtex per filament.

Various additives may also be used in the elastic fibers of the present invention. Exemplary additives include chlorine resistant additives; an antibacterial agent; an antioxidant; thermal stabilizers (e.g., 1, 2-bis (3, 5-di-tert-butyl-4-hydroxyhydrocinnamoyl) hydrazine); UV stabilizers (e.g., 2- (2 ' -hydroxy-3 ', 5 ' -di-tert-butylphenyl) -benzotriazole; 2- (2 ' -hydroxy-5 ' -tert-octylphenyl) benzotriazole; 2- (2 ' -hydroxy-3 ', 5 ' -di-tert-butylphenyl) -5-chlorobenzotriazole; 2- (2 ' -hydroxy-3 ' -tert-butyl-5 ' -methylphenyl) -5-chlorobenzotriazole; 2- (2 ' -hydroxy-5 ' -methylphenyl) -benzotriazole); a gas-resistant stabilizer; pigments (e.g., ultramarine green); matting agents (e.g. titanium dioxide); anti-tack additives (e.g., ethylene bis stearamide, ethylene bis oleamide); a heat-setting additive; a dye; an emulsifier; a wetting agent; an antistatic agent; a pH adjusting agent; filament hot pressing preshrinking agent (filament compressing); a preservative; dispersants (e.g., soluble ionic dispersants; soluble nonionic dispersants; soluble amphoteric dispersants); lubricants (e.g., silicone oils), and the like. Up to about 15 wt% of additives based on the weight of the total reactants may be used; 0 wt% to about 10 wt%; 0 wt% to about 5 wt%; about 0.1 wt% to about 3 wt%.

In one embodiment of the invention, the elastic fiber-forming composition includes at least one thermal stabilizer. The heat stabilizer can be 1, 2-bis (3, 5-di-tert-butyl-4-hydroxy hydrogen cinnamoyl) hydrazine. From 0 wt% to about 2 wt% thermal stabilizer may be used based on the polyurethane, or from about 0.001 wt% to about 1 wt% based on the polyurethane.

In another embodiment of the invention, the elastic fiber-forming composition includes at least one additional dispersant. In one embodiment of the invention, the dispersant is a soluble ionic dispersant. From 0 to about 1 wt% of dispersant, based on the polyurethane, may be used; or from about 0.001 wt% to about 0.1 wt% based on the polyurethane.

In another embodiment of the present invention, the elastic fiber-forming composition further comprises at least one pigment. In another embodiment of the present invention, the pigment is ultramarine. From 0 to about 0.5% by weight of pigment, based on the polyurethane, can be used; or from about 0.001 wt% to about 0.1 wt% based on the polyurethane.

In another embodiment of the invention, the elastic fiber-forming composition includes at least one matting agent. In another embodiment of the invention, the matting agent is titanium dioxide. From 0 to about 1 wt% of matting agent, based on the polyurethane, can be used; or from about 0.01 to about 0.5 wt% based on the polyurethane.

In another embodiment of the present invention, the elastic fiber-forming composition further comprises at least one ultraviolet light stabilizer. In one embodiment, the UV stabilizer is 2- (2 ' -hydroxy-3 ', 5 ' -di-t-butylphenyl) benzotriazole. From 0.01 to about 1 wt% of the UV stabilizer may be used.

Anti-tack additives or anti-blocking agents known in the art may be used in the practice of the present invention. Exemplary anti-tack additives and anti-blocking agents include metal stearates and barium sulfate. In one embodiment, about 0 to 2 wt% of the anti-tack additive/anti-blocking agent is used based on the polyurethane, preferably about 0.01 wt% to 1 wt% based on the polyurethane.

Chlorine resistant additives known in the art may be used in the practice of the present invention. Exemplary chlorine resistant additives include aluminum magnesium hydroxide carbonate hydrate; hydrotalcite and hydrated magnesium carbonate. In one embodiment, the hydrotalcite has crystal water and is modified to have C attached thereto_10-30Fatty acids (e.g. capric acid, lauric acid, myristic acid, palmitic acid, stearic acid). About 0 to 10 wt% of the chlorine resistant additive, based on the polyurethane, may be used; or about 0 wt% to 4 wt% based on the polyurethane. When used with hydromagnesite, huntite, zinc oxide, and poly (N, N-diethyl-2-aminoethyl methacrylate), the elastic fibers can have excellent anti-yellowing properties and high mechanical chlorine resistance. From 0 to about 5 weight percent of the chlorine resistant additive may be used; or from about 0.1 wt% to about 3 wt%.

Heat-setting additives known in the art may be used in the present invention. Exemplary heat-set additives include quaternary amine additives such as those described in U.S. patent 6,403,682, the disclosure of which is incorporated by reference in its entirety. In one embodiment, the heat-setting additive is a quaternary amine having a functionality of about 3 to about 100 meq/kg. Other heat-setting additives include alkali metal salts of monocarboxylic acids or thiocyanic acid. Alkali metals that form salt cations include lithium, sodium, and potassium. A suitable salt anion is C_1-10A carboxylate or a thiocyanate. The carboxylate may be derived from formula R¹Aliphatic monocarboxylic acids of COOH, wherein R¹Is a chain of hydrogen or carbon atoms, e.g.Such as C_1-7And (3) a chain. R of carbon atom¹The chain may be saturated or unsaturated, linear or branched. R¹May have a small number of substituents such as lower alkyl, halogen, etc. In one embodiment, the heat-setting additive is acetic acid. The carboxylate may be derived from an aromatic monocarboxylic acid and has the general formula: r³R²R⁴COOH, wherein R²Is a benzene ring, R³Is hydrogen, chlorine, bromine or C_1-4Lower alkyl, R⁴Is optionally or methylene, ethylene or vinylene. Anions derived from aromatic monocarboxylic acids include benzoate, cinnamate and chlorobenzoate. The salt additive can help improve the heat-set characteristics of the elastic fiber when the salt amount reaches 0.02 to 0.25 wt% of the elastic fiber polymer. When the anion is thiocyanate or derived from an aliphatic monocarboxylic acid, the effective amount of salt may be less than 0.1%. When the carboxylate anion is derived from an aromatic monocarboxylic acid, an effective amount of the salt may be up to 0.2%. Alkali metal benzoates, such as potassium benzoate, can be used at concentrations of 0.03 to 0.09 percent based on the weight of the elastomeric fiber polymer.

Antioxidants provide high temperature stability and long term storage stability. Any antioxidant known in the art, such as amine and phenol based antioxidants, can be used in the elastic fibers of the present invention. Exemplary amine-based antioxidants include N, N-di (nonylphenyl) amine, diaryldiamines (e.g., N ' -diphenylethylenediamine, N ' -ditolylethylenediamine), naphthylamines (e.g., N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine), aromatic amines (e.g., N ' -diisobutyl-p-phenylenediamine, N-cyclohexyl-N ' -phenyl-p-phenylenediamine, N ' -dinaphthyl-p-phenylenediamine, N ' -ditolylphenylp-phenylenediamine, N ' -diphenyl-p-phenylenediamine, 6-ethoxydihydroquinoline, 4-isopropoxydiphenylamine), and alkylated diphenylamines. Exemplary phenol-based antioxidants include biphenol, monophenol, polyphenol, and aminophenols. Phenol-based antioxidants include 2, 2 '-methylenebis (4-methyl-6-tert-butylphenol), 4' -methylenebis (2, 6-di-tert-butylphenol), 4 '-butylidenebis (3-methyl-6-tert-butylphenol), 4' -thiobis (3-methyl-6-tert-butylphenol, 4-tert-butylcatechol, monomethyl ethers of hydroquinone, 2, 6-di-tert-butyl-p-cresol, 1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 2,4, 6-tetraaminophenol, and the like Bis (2, 4-dichlorobenzyl) hydroxylamine or a mixture thereof. In one embodiment, the antioxidant is triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate. In one embodiment, about 0 to 2 wt.% antioxidant, based on the polyurethane, is used; or about 0% to 1% by weight based on the polyurethane.

Lubricants known in the art, such as dimethylsiloxane, polydimethylsiloxane, organomodified dimethylsiloxane, organomodified polydimethylsiloxane, or mixtures of two or more thereof, may also be used. Other lubricants include mineral oils, and fatty acids containing from 8 to 22 carbon atoms in the fatty acid component and from 1 to 22 carbon atoms in the alcohol component. Specific examples include methyl palmitate, isobutyl stearate and 2-ethylhexyl tallow fatty acid, carboxylic esters of polyhydric alcohols, esters of coconut fatty acid or glycerol and alkoxylated glycerol, silicones, dimethylpolysiloxanes, polyalkylene glycols and ethylene oxide/propylene oxide copolymers, and other combinations of higher fatty acids including magnesium stearate and palmitic/stearic acids.

The elastic fiber should exhibit excellent lubricity, static resistance and long-term storage stability. For example, the elastic fiber may be treated with a fiber treatment composition comprising polydimethylsiloxane, a polyoxyalkylene functional diorganopolyorganosiloxane, and an antioxidant. The antioxidants may have linear or branched chains and may be linear or cyclic. In the case of the linear structure, the molecular chain terminal group may be a trimethylsiloxy group or a dimethyldihydroxysiloxy group. Such a fiber treatment composition may comprise, for example, 100 parts by weight of a fiber having a viscosity of 3 to 30mm at 25 ℃²A dimethylpolysiloxane per second, and from 0.5 to 50 parts by weight of a polyoxyalkylene-functional diorganopolysiloxane.

The present invention also provides a package of an elastomeric fiber supply comprising a core (e.g., a cylindrical core) and an elastomeric fiber of the present invention wound on the core.

Articles of clothing (e.g., intimate apparel, swimwear, athletic apparel, stockings, socks, garments, suits, outerwear, and the like) and/or disposable personal care products (e.g., baby diapers, feminine care products, adult incontinence garments, protective masks, medical garments, industrial garments, and the like) comprising the elastic fibers of the present invention can be made with the elastic fibers produced by the present invention.

The elastic fibers of the present invention may be used in the incorporation of one or more natural and/or synthetic fibers and/or yarns, such as nylon, polyester, rayon, acrylic, acetate, elastic, wool, hemp, Ningma, jute, cotton, linen, and the like, in articles of clothing, personal care products, or other fabrics. The elastic fibers of the present invention may be used in combination with fibers and/or yarns.

Methods of making stretch fabrics are known, including fabric design and construction, filling stretch, texturing stretch and bi-directional stretch of woven fabrics, heat setting and dyeing and finishing. The core spun yarn is a combination yarn produced by: a "stiff" fiber sheath (i.e., a generally stretched, oriented inelastic fiber, filament, or strand) is spun around an elastic strand core while the elastic strand (e.g., elastic fiber) is placed under tension and elongated to several times its relaxed length. The tension is then released and the elastic core strands contract to produce a stretchable combination yarn. Other methods for making stretchable combination yarns are known in which elastic strands are combined with stiff fibers, for example by draping, air jet entanglement, braiding, and the like. However, woven stretch fabrics made with such combination yarns typically have dimensions that are much smaller than the length and width of the loom on which the fabric is woven.

Fabrics or garments comprising elastic fibers are typically heat-set under tension to stabilize their dimensions. Heat-set "the elastic fibers in an extended form. Heat setting is also known as re-fibrillation (re-fibrillation), whereby a higher denier elastic fiber is drawn or stretched to a lower denier and then heated to a sufficient temperature and for a sufficient time to stabilize the elastic fiber at a lower denier. Heat setting permanently changes the elastic fiber at the molecular level such that the recovery tension in the majority of the stretched elastic fiber is removed and the elastic fiber becomes stable at new and lower deniers. According to the present invention, a sufficient temperature for heat setting may be about 130 ℃ to about 175 ℃ instead of 185-195 ℃ as currently used in many industrial production processes. The optimum temperature and heat-set time will depend on the particular elastic fiber-forming material used and can be readily determined by one skilled in the art.

The fabric produced according to the present invention comprises the elastic fiber of the present invention and at least one companion fiber. The companion fiber comprises one or more man-made and/or natural fibers and/or yarns. Artificial and natural fibers and/or yarns include nylon, polyester, rayon, acrylic, acetate, elastic, wool, hemp, Ningma, jute, cotton, linen, and the like. The elastomeric fibers of the present invention may be combined with artificial and/or natural fibers and/or yarns by operations such as entangling, covering, core spinning, air jet mixing, air jet entangling, weaving, and the like.

In one embodiment of the invention, the fabric or combination yarn comprises the elastic fiber of the invention and cotton. In another embodiment, the fabric or combination yarn comprises the elastic fiber of the present invention and wool. In another embodiment, the fabric or combination yarn comprises the elastic fiber of the present invention and rayon.

Any method known to those skilled in the art for producing spandex polymers can be used to produce the polyurethane/urea elastomers and spandex of the invention. Such methods are disclosed, for example, in U.S. Pat. nos. 3,384,623; 3,483,167, respectively; and 5,340,902, incorporated herein by reference.

Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.

Examples

The test method comprises the following steps:

elongation and modulus testing: a sample of the material to be tested was cut into approximately twelve inches with scissors or a 12 "gauge guillotine and immediately tested with an Instron model 4502 constant speed with an external meter equipped with a 10 newton full scale load cell. Care was taken to ensure that the test material was not stretched prior to testing. The samples were cycled between 0 and 300% elongation ranges at a constant rate of elongation of 35 inches/minute during a particular cycle. Load force (LP) is the stress applied to the fiber at a particular% elongation. After 1 cycle, the fiber was drawn to a defined elongation.

And (3) tensile test: the tensile strength of the material to be tested was measured with a ball dynamometer having an 1/2 "diameter pivot axis and a spring gauge or digital dynamometer was mounted vertically, which recorded the force in ounces or pounds. The scale has a pulley that must be located about 4 inches from the dynamometer stand axis.

A sample of the material to be measured is looped over a pulley or pulley equivalent of the scale. The dynamometer shaft is then rotated. When the shaft is rotated, the loose end of the sample is wrapped around the shaft until the end is collected and the sample itself begins to rotate. The maximum load is then recorded in pounds. Tenacity was calculated by converting the pound-force value to grams and dividing by 2 times the initial denier of the fiber.

Isocyanate moiety%: in the examples,% isocyanate moiety content of the blocked diol is calculated according to the following formula:

% NCO ═ 100 × (2 × NCOfw × (c.r. — 1))/(diol mw + (c.r. × diisocyanate mw))

Where "fw" refers to the formula molecular weight, "mw" refers to the molecular weight, "c.r." refers to the capping ratio (molar ratio of diisocyanate to polymeric diol), "diol" refers to the polymeric diol, and "NCO" refers to the isocyanate moiety, which has a formula molecular weight of 42.02. In order to improve spinning continuity, it is preferred that the capped glycol used in making the elastic fiber of the present invention have an NCO moiety content of about 2.25 to 4.00%.

Heat-setting efficiency: to measure heat-set efficiency, the elastic fiber samples were mounted on a 4 inch frame and stretched 1.5 times (50%). The frame (with sample) was then placed horizontally in an oven and preheated to the test temperature for two minutes. The frame (with the fibers) was then removed from the oven and allowed to cool to room temperature. The sample still on the frame was immersed in boiling water for 30 minutes. The frame and fibers were then removed from the bath and allowed to dry. The length and heat-set efficiency of the fiber samples were measured and calculated (HSE) according to the following formula:

% heat-set efficiency of 100 × (heat-set length-initial length)/(stretched length-initial length)

The materials used in the examples are as follows:

POLYOL A: a polyoxypropylene diol, having a molecular weight of 2000Da, and an unsaturation level of about 0.005 meq/g.

POLYOL B: polytetramethylene ether glycol having a number average molecular weight of 2,000.

MDI: 4, 4' -diphenylmethane diisocyanate.

ZNO: zinc octoate (commercially available as Borcher's Octa-Soligen Zn 22).

DMAc: and (3) dimethylacetamide.

EDA (electronic design automation): ethylene diamine.

IPDA: isophorone diamine.

DEA: diethylamine.

Example 1

254g of dehydrated POLYOL A and 254g of dehydrated POLYOL B were added to a 1 liter reaction flask in the amounts indicated in Table 1. 132.7g of MDI was added at 55 ℃ and the reaction was carried out for 2 hours 15 minutes at 76 ℃ to form a mixture of isocyanate-terminated prepolymer and unreacted diisocyanate. 264g DMAc was added to the mixture and stirred until the reaction mixture was homogeneous.

After 1 hour, the chain extender components consisting of ethylenediamine, isophoronediamine and diethylamine, in the amounts indicated in table 1, dissolved in DMAc, were added to the reaction mixture. An additive slurry containing a gas attenuating additive, an antioxidant, a thermal stabilizer, an anionic dispersant, ultramarine, titanium dioxide, and an antiblocking agent is thoroughly mixed into a prepolymer and chain extender solution. After mixing for one hour under vacuum, the resulting elastic fiber solution was transferred into quart bottles. The elastic fiber solution is then spun into fibers by standard dry spinning methods. The properties of these fibers are reported in table 1.

Comparative examples 2 to 4

The method used in comparative examples 2 to 4 was the same as that used in example 1. Table 1 shows the relative amounts of materials used and the properties of the fibers produced.

Comparative example 5

In an autoclave reactor, a single batch of 73kg prepolymer was prepared from MDI, poiol a and poiol B in the amounts indicated in table 1. The prepolymer was diluted with DMAc and reacted with a DMAc/amine stream in a continuous mechanical polymerizer to obtain a solution having the composition and characteristics shown in table 1. On an equivalent substrate, there was a 2% excess of amine groups over NCO groups. The solution was then dry spun to form 40 denier fibers. The properties of these fibers are reported in table 1.

Comparative example 6

A blend of 1495g POLYOL A and 996.5g POLYOL B was dehydrated in vacuum at 120 ℃ for 1 hour. After cooling to room temperature, 50ppm of ZNO was admixed. 531.9g of MDI were added at 55 ℃. The reaction mixture was heated at 80 ℃ for 90 minutes until the prepolymer had an NCO content of 2.39%.

1296.4g DMAc were added to the prepolymer at 60 ℃ and the mixture was cooled to 25 ℃. The homogenized mixture of prepolymer and DMAc had an NCO content of 1.62%. 18.48g of EDA, 9.52g of IPDA, 1.36g of DEA and 2474g of DMAc are added to 1804g of diluted prepolymer and mixed rapidly. After one hour of mixing, the resulting solution had a viscosity of 55.0 pas. An additional 69.0g of the diluted prepolymer was added and mixed for 30 minutes. The solution had a viscosity of 89 pas at this time. An additional 39.2g of the diluted prepolymer was added and mixed for 30 minutes. This produced a final solution with a viscosity of 102Pa · s and a solids content of about 30%.

Mixing 0.3 wt% magnesium stearate, 2.0 wt% Cyanox^*1790 antioxidant (commercially available from Cyanamid), 0.5 wt% Tinuvin^*622 stabilizer (commercially available from Ciba-Geigy) and 0.3 wt% of a polyether siloxane Silwet^*L7607 (product of Union Carbide Corp, USA) was added to the viscous polymer solution (amounts based on polyurethane solids). The solution was then dry spun to form 40 denier fibers. The properties of these fibers are reported in table 1.

It can be seen from table 1 that only compositions within the scope of the present invention give the desired heat-set efficiency, and good toughness, elongation, modulus, elasticity and chemical resistance.

In comparative example 2, an increase in the percentage of low unsaturation polyoxypropylene diol in the polyol component and a decrease in the capping ratio resulted in a great improvement in HSE, although the level of asymmetric diamine was very similar to that of example 1. However, the composition of example 2 is not practical due to the very low modulus of the fibers made from the composition and poor spinning performance.

In comparative example 3, the polyol composition was the same as in example 1. The end-capping ratio and prepolymer% NCO were also almost the same as in example 1. However, the level of asymmetric diamine (IPDA) was much higher than that used in example 1. While the final fiber made from the composition exhibits good elongation, it has an unacceptably low modulus and poor spinning continuity.

In comparative example 4, the polyol composition was again the same as in example 1, but the% NCO was higher than in example 1 and outside the scope of the present invention. Polyurethane/ureas containing high% NCO values based on prepolymers require larger amounts of asymmetric diamines to have adequate heat-set efficiency. In example 4, no linear diamine was used and the diamine component was based only on asymmetric IPDA. The resulting fibers have desirably high heat-set efficiency at 150 ℃. It also spun well, but with low tenacity and elongation. Furthermore, the fibers prepared based on the composition are extremely tacky and have insufficient resistance to chemicals commonly encountered in fabric washing, bleaching and dyeing operations.

In comparative example 5, the percentage of the low unsaturation polyoxypropylene diol in the polyol component was 40 equivalent%. The prepolymer end-capping ratio was 1.65 and the% NCO was 2.26. Because of the low end-capping ratio, the resulting elastic fiber has excellent elongation and toughness. However, the fibers have insufficient heat-set efficiency due to the low percentage of asymmetric diamine chain extender used in this example.

In comparison, the fibers in comparative example 6 showed improved HSE relative to the fibers in comparative example 5. The higher HSE in comparative example 6 particularly surprisingly resulted in a slightly higher capping fraction and prepolymer% NCO. In comparative example 6, the same level of asymmetric diamine was used as in comparative example 5, but a greater percentage of low unsaturation polyoxypropylene diol was used in the polyol component.

TABLE 1

Examples	1	2*	3*	4*	5*	6*
							POLYOL A(eq.％)	50	65	50	50	40	60
POLYOL B(eq.％)	50	35	50	50	60	40
							NCO:OH	2.09	1.575	2.05	2.4	1.65	1.70
Prepolymer (% NCO)	3.63	2.01	3.51	4.52	2.26	2.43
							ZNO，ppm	25	45	25	25	50	50
EDA(eq.％)	39.0	37.5	0	0	80.5	82.5
							IPDA(eq.％)	58.5	60	97.5	97.5	15	15
DEA(eq.％)	2.5	2.5	2.5	2.5	4.5	2.5
							Spinning speed (feet/minute)	2850	2850	2850	2850	2624	2624
Properties of the fiber
							Denier	30	40	30	30	40	40
Toughness (gm/denier)	1.10	--	0.91	0.76	1.25	1.38
							Elongation (%)	468	--	450	347	515	527
First cycle, LP2001(gm/denier)	0.081	--	0.061	0.174	0.15	0.14
							First cycle, LP2502(gm/denier)	0.122	--	0.087	0.28	--	--
First cycle, LP3003(gm/denier)	0.194	--	0.129	0.45	0.26	0.23
							Second cycle, LP2004(gm/denier)	0.046	--	0.034	0.58	--	--
Second cycle, LP2505(gm/denier)	0.072	--	0.052	0.106	--	--
							HSE at 150 ℃%	--	72	--	85	--	--
HSE at 170 ℃%	70	90	--	--	51	58
							Spinning performance	Good effect	Difference (D)	Difference (D)	Good effect	--	--
Note	Good HSE; no stickiness; good chemical resistance; good modulus; good elongation	Very low modulus	A low modulus; stickiness; poor chemical resistance	Stickiness; poor chemical resistance	Low HSE	Low HSE

^*Comparative example

eq% equivalent percentage

¹Load force at 200% elongation after first cycle

²Load force at 250% elongation after first cycle

³Load force at 300% elongation after first cycle

⁴Load force at 200% elongation after second cycle

⁵Load force at 250% elongation after second cycle

It should be noted that the spinning speed used in these examples is much higher than that cited in many other patents. Therefore, the heat-set results here cannot be directly compared with those found in other patents. At high spinning speeds, the heat-setting results are considered quite good.

The% NCO range used in the present invention is about 2.25 to 4%. As the proportion of asymmetric diamine in the chain extender mixture increases, the% NCO increases. If the% NCO is too low, the load force becomes too low and it becomes difficult to spin the polyurethane/urea solution into spandex. If the% NCO is too high, the elongation and heat-set efficiency of the elastic fiber become low, and the load force becomes undesirably high. At high% NCO levels, a large percentage of asymmetric diamines are required in the chain extender mixture to obtain fibers with suitable heat-set efficiency. However, too high a level of asymmetric diamine can reduce the chemical resistance of the fibers, chemicals being alcohols, dyes, bleaches and other chemicals that may be encountered during fabric production and fixing operations. As can be seen in the previous examples, only compositions within the scope of the present invention give the desired heat-set efficiency at low temperatures, as well as good toughness, elongation, modulus, elasticity and chemical resistance.

Having now fully described this invention, it will be apparent to those of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

Claims (15)

1. A segmented polyurethane/urea produced by reacting in solution the following a) and b) in the presence of c):

a) an isocyanate terminated prepolymer having a free isocyanate group content of from about 2.25 to about 4 percent which is the reaction product of:

(1) a stoichiometric excess of at least one diisocyanate, and

(2) an isocyanate-reactive component comprising:

(i) a diol component comprising:

(a) from about 25 equivalent percent to about 75 equivalent percent of at least one polyoxypropylene diol having a molecular weight of at least 1500Da and an average unsaturation level of less than or equal to 0.03meq/g, and

(b) about 25 equivalent percent to about 75 equivalent percent of at least one polytetramethylene ether glycol having a molecular weight of about 600Da to about 6000 Da; and optionally

(ii) One or more other materials comprising at least one functional group reactive with isocyanate groups, provided that the sum of the equivalent percentages of (i) and (ii) is 100 equivalent percentages, and

b) a diamine chain extender comprising:

(1) from greater than 25 to about 75 equivalent percent of at least one asymmetric aliphatic and/or cycloaliphatic diamine, based on the total equivalents of b), and

(2) at least one linear diamine, wherein the diamine is selected from the group consisting of,

c) a solvent.

2. The polyurethane/urea of claim 1 wherein from about 30 to about 70 equivalent percent of the diamine chain extender is an asymmetric aliphatic and/or cycloaliphatic diamine.

3. The polyurethane/urea of claim 1 wherein 35 to 65 equivalent percent of the diamine chain extender is an asymmetric aliphatic and/or cycloaliphatic diamine.

4. The polyurethane/urea of claim 1 wherein the ethylenediamine is a linear diamine.

5. The polyurethane/urea of claim 1 wherein from about 40 to about 65 equivalent percent of the polyol component is a polyoxypropylene diol having a molecular weight of at least 1500Da and an average level of unsaturation of less than about 0.03 meq/g.

6. The polyurethane/urea of claim 1 wherein the polyoxypropylene diol having an average unsaturation level of less than about 0.03meq/g has an average molecular weight of from about 2000 to about 8000 Da.

7. The polyurethane/urea of claim 1 wherein the polyoxypropylene diol having a molecular weight of at least 1500Da has an average level of unsaturation of less than 0.02 meq/g.

8. The polyurethane/urea of claim 1 wherein the diisocyanate is diphenylmethane diisocyanate.

9. Spun spandex from the polyurethane/urea of claim 1.

10. A process for producing elastic fibers comprising spinning a polyurethane/urea which is the reaction product of the following a) and b) in c):

a) an isocyanate-terminated prepolymer which is the reaction product of:

(1) a stoichiometric excess of diisocyanate, and

(2) an isocyanate-reactive component comprising:

(i) a diol component comprising:

(a) from about 25 equivalent percent to about 75 equivalent percent of at least one polyoxypropylene diol having a molecular weight in excess of about 1500Da and an average unsaturation level of less than about 0.03meq/g, and

(b) about 25 equivalent percent to about 75 equivalent percent of at least one polytetramethylene ether glycol having a molecular weight of at least 600 Da; and

optionally (c) is

(ii) One or more other materials comprising at least one functional group reactive with isocyanate groups, with the proviso that the sum of the equivalent percentages of (i) and (ii) is 100 equivalent percentages,

the prepolymer has a free isocyanate group content of from about 2.25 to about 4%,

and

b) a diamine chain extender comprising:

(1) about 25 to about 75 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine, based on the total equivalents of b), and

(2) at least one linear diamine, wherein the diamine is selected from the group consisting of,

c) a solvent.

11. The method of claim 10 wherein the diisocyanate is diphenylmethane diisocyanate.

12. The method of claim 10, wherein the linear diamine is ethylene diamine.

13. The process of claim 10 wherein 30 to 70 equivalent percent of the diamine chain extender is an asymmetric aliphatic and/or cycloaliphatic diamine.

14. The process of claim 10 wherein 35 to 65 equivalent percent of the diamine chain extender is an asymmetric aliphatic and/or cycloaliphatic diamine.

15. The process of claim 10 wherein the solvent is dimethylacetamide.