MXPA97007960A - Non-two-composite fibers that have a nucleus formed of regenerated polymeric materials and methods to make lasmis - Google Patents

Abstract

The present invention relates to a bicomponent fiber comprising a core having a cyclic caprolactam dimer and a polyamide sheath

Description

BIRTHDAY FIBERS NOVEDOSAS THAT HAVE DOMAIN OF NUCLEUS - FORM OF REGENERATED POLYMERIC MATERIALS AND METHODS TO MAKE THE SAME FIELD OF THE INVENTION The present invention relates to the field of synthetic fibers. More particularly, the present invention relates to synthetic bicomponent fibers which have a sheath-core structure. In particularly preferred ways, the present invention is modalized into multilobal bj_ component fibers having a polyamide sheath that completely rounds off a core formed of a re generated polymeric material.

BACKGROUND AND COMPENDIUM OF THE INVENTION Polyamide has been used extensively as a synthetic fiber. While its structural and mechanical properties make it attractive for use in such capacities such as carpeting, it is relatively expensive nonetheless. Therefore, it would be desirable to replace a portion of polyamide fibers with a core formed of a material of relatively lower cost. In this regard, some polymeric materials are attractive candidates as a partial replacement of the polyamide are "out of specification" - that is, they are not themselves suitable for use in fiber spinning. A particularly attractive candidate "out of specification" is regenerated polymeric materials, for example, polymeric material obtained from recycled post-consumer waste products eg, thermoplastic containers, waste carpeting and the like. However, replacing a portion of a 100% polyamide fiber with a core portion of regenerated polymeric material can affect the mechanical properties of the fiber to a degree that would no longer be useful in its intended end use application ( e.g., such as a carpet fiber). Additionally, many regenerative polymeric materials are already colored (e.g., by the use of a dye or dye). Therefore, their use as a material for making useful products (eg, carpet fibers) is usually limited by the color of the regenerated polymeric materials obtainable. Typically, only clear regenerated polymeric materials are used for such purposes since the manufacturer can then add pigments or dyes to provide products of desired color. Recently, the Patent of E.U.A. No. 5,549,957 proposed multilobal composite fibers having a ny-lon sheath of a fiber-forming polymer which may be, for example, "out of specification" or recovered polymers. (Column 4, lines 6-8). The core can be polyethylene terephthalate, - polypropylene, high density polyethylene, polyester or polyvinyl chloride. (column 4, lines 17-20). The core is covered with a virgin nylon sheath that constitutes between 30% 50% by weight of the core / sheath fiber. (Column 3, lines 65 67). Broadly, the present invention relates to a bicomponent fiber structure having a polyamide domain and another domain of different cross-section formed from a colored, regenerated polymeric material. The regenerated limbic po domain is embedded completely within, and thus completely surrounded by the polyamide domain. Preferably, the fibers of this invention have a concentric sheath-core structure whereby the pyrimid domain forms the sheath and the regenerated polymer forms the core Surprisingly, even when the core is formed of a regenerated colored polymer material, The bicomponent sheath-core fibers of this invention exhibit properties that are in many respects compatible with the fibers formed of 100% polyamide (virgin). For example, the virgin polymer sheath component of the bicomponent fibers of this invention may be colored to such an extent that the colored regenerated polymer core in the core is "hidden." A further aspect of this invention is that the polymeric material regenerated colored is mixed with a colored leveler - for example, a black pigment, such as carbon black. In this regard, it is known that most recycled (recycled) polymer materials will have some color variation. Typically a gray-green tone. In accordance with the present invention, therefore, the regenerated colored polymeric material will first be measured against a known, conventional color standard. A specified nature of a color leveler (e.g., carbon black) would then be added to colored polymeric material regenerated to correct its color to the known standard. Next, the color corrected re generated polymeric material may be incorporated into the core of a sheath-core fiber in accordance with this invention. Additional aspects and advantages of this invention will become more apparent after careful consideration provided to the following detailed description of preferred exemplary modalities thereof.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY MODALITIES As used herein and in the accompanying claims, the term "fiber former" attempts to identify linear polymers, at least partially partially crystalline oriented, which are capable of forming into a structure of fiber having a length at least 100 times its width and capable of stretching without breaking by at least 10%. The term "non-fiber-forming", therefore, attempts to refer to amorphous (non-crystalline) linear polymers that can be formed into a fiber structure, but which are unable to stretch without breaking by at least about 10%. The term "fiber" includes fibers of extreme or indefinite length (filaments) and fibers of short length (solid fiber). The term "hi 1o2" refers to a continuous strand or "fiber bundle." The term "regenerated polymer" is intended to refer to recycled post-consumer polymeric waste materials that are, in and of themselves, non-fiber formers. The term "bicomponent fiber" is a fiber which has at least two different cross-sectional domains formed resively of different polymers.The term "bicomponent fiber in this manner is intended to include - concentric sheath-core fiber structures and Eccentric and island fiber structures in the sea. Preferred in accordance with the present invention are concentric bicomponent core-vain fiber structures having a polyamide shell and a regenerated polymer core, and thus, the following discussion will be directed to said embodiment. preferred However, the present invention is also applicable to other bicomponent fiber structures having a polyamide domain and a non-fiber-forming regenerated polymer domain embedded entirely within, and thus completely surrounded by the polyamide domain. the term "linear polymer" is intended to encompass polymers having a straight chain structure wherein less than about 10% of the structural units have side chains and / or branches The preferred polyamides useful for forming the sheath of the bicomponent fibers of this invention are those which are generically known by the term "nylon" and are long chain synthetic polymers containing amide bonds (-C0-NH-) along the main polymer chain. , hi 1 ab by melting, suitable for the sheath of bicomponent sheath-core fibers of this invention include those obtained by the polymerization of a lactate or an amino acid, or those polymers formed by the condensation of a diamine and a dicarboxylic acid Typical polyamides useful in the present invention include nylon 6, nylon 6/6, nylon 6/9, nylon 6/10, nylo n and T, nylon 6/12, nylon 11, nylon 12, nylon 4,6 and copolymers thereof or mixtures thereof. The polyamides can also be nylon 6 or nylon 6/6 copolymers and a * nylon salt obtained by reacting a dicarboxylic acid component such as terephthalic acid, isophthalic acid, adipic acid or sebacic acid with a diamine such as hexamethi lendiami. na, etaxi lendiami na, or 1,4-bisaminomethylcyclohexane. Preferred are pol i-epsi lon-caprol actama (nylon 6) and adipamide polyhexamethylene (nylon 6/6). Nylon 6 is most preferred. Importantly, the core of the core sheath fibers according to this invention is formed of a polymeric material that is obtained. from recrystallized polymer products, preferably colored, regenerated. The regenerated polenic material forming the core of this invention will have some color variation * from batch to batch. Typically the colored regenerated polymeric material will be a gray-green shade The core will represent less than about 50% by weight of the fibers in accordance with this invention, with the va na representing more than about 50% by weight. More preferably, the core will be about 30% by weight or less of the fibers according to this invention, with the vain being present in the fibers in an amount of about 70% by weight or greater. The sheath-core fibers are spun using conventional fiber-forming equipment. Thus, for example, separate melt flows from the sheath and core polymers are fed to a conventional sheath-core spinneret nozzle package such as those described in US Patents. Nos. 5,244,614, 5,162,074, 5,125,818, 5,344,297 and 5,445,884 (the entire contents of each patent being expressly incorporated herein by reference) wherein the melt flows combine to form multi-lobed extruded fibers (e.g. , tetra-, penta- or hexalobales) that have sheath and core structures. Preferably, the fibers have a trilobal structure with a modification ratio of at least about 2.0, more preferably between 2.2 and 4.0. In this regard, the term "modification ratio" means the relation R. / ^ »where R is the radius of the largest circle that is entirely within a cross section of the fiber, R. is the radius of the circle circumscribing the cross section . The extruded fibers are rapidly cooled, for example with air, in order to solidify the fibers. The fibers can then be treated with a finish comprising a lubricating oil or mixture of oils and antistatic agents. The fibers formed in this manner are then combined to form a bundle of yarn which is then wound onto an appropriate package. In a subsequent step, the yarn is stretched and textured to form a bulky continuous fiber (BCF) yarn suitable for laying on carpets. A more preferred technique involves combining the extruded fibers or how they are spun into a yarn then stretching, texturing and winding to an all-in-one package. &ampThe one-step method for making BCF is generally known in the art as side-stretched-textured (SDT) / nylon fibers for the purpose of manufacturing carpet have linear densities in the range of about 3 to about 75 denér / fi 1 amento (dpf) (denér = weight in gram of a single fiber with a length of 9000 meters). A more preferred scale for carpet fibers is from about 15 to 28 dpf.

The BCF yarns can pass through various processing steps well known to those skilled in the art. For example, to produce carpets for floor covering applications, the BCF yarns generally flow toward a collapsible primary backing or reinforcement. The primary reinforcing materials are generally selected from woven jute, woven polypropylene, nonwoven cellulosics and non-woven nylon, polyester and polypropylene. The primary reinforcement is then coated with an appropriate latex material such as a conventional styrene-butadiene latex (SB), vinylidene chloride polymer, or vinylidene chloride-vinylidene copolymers. It is common practice to use fillers such as calcium carbonate to reduce latex costs. The final purpose is to apply a secondary reinforcement, usually a woven yut or woven synthetic such as polypropylene. Preferably, carpets for floor covering applications will include a woven polypropylene primary reinforcement, a conventional SB latex formulation, and either a woven jute or a reinforced woven polypropylene secondary carpet. The SB lathe may include calcium carbonate filler and / or one or more of the hydrate materials listed above. While the foregoing discussion has emphasized the fibers of this invention that are formed into continuous vibrations that are voluminous for purposes of making carpet fibers, the fibers of this invention can be processed to form fibers for a variety of textile applications. In this regard, the fibers may be curled or otherwise textured and then cut to form random lengths of short fibers having individual fiber lengths of about 3.81 to about . 32 centimeters The fibers of this invention can be dyed or colored using conventional fiber coloration techniques. For example, the fibers of this invention can be subjected to an acid dye bath to achieve the desired fiber coloration. Alternatively, the nylon sheath can be colored in the fusion before the formation of fiber (ie, dyed in solution) using conventional pigments for that purpose. A further understanding of this invention will be obtained from the following non-limiting Examples that illustrate specific embodiments thereof.

EXAMPLES Example 1 (Invention) In this Example 1 polymer nylon 6 () (Ultramid 'nylon BS-700F commercially available from BASF is used.

Corporation) and a regenerated polymeric material obtained from recycled nylon carpets having 90% nylon 6 and 10% dirt and reinforcing contaminants. The materials are extruded using equipment as described in the U.S. Patent. 5,244,614. The relative amounts of each component are 75% by weight of nylon 6 in the sheath and 25% by weight of nylon 8 recycled in the core. The extruder zone temperatures for each polymer are 275eC for nylon 6 and 275C for recycled nylon 8. The spinning packs temperature is 270d. The polymers are delivered to a spin pack designed using thin plates such as those described in the U.S. Patent. No. 5,458,972 (the entire contents of which is incorporated herein by reference), particularly the Figure thereof, so as to form a tril bal bicomponent fiber having a core of concentric circular cross section. The fiber is cooled, stretched and textured in a continuous spinning-stretching apparatus (Rieter JO / 10). The standard ratio is 2.8 and the winding speed is 2200 meters per minute.

Example 2 (Invention) In this Example 2 nylon 6 (R) polymer (Ultramid; nylon ND-700F commercially available from BASF Corporation) and a regenerated polymeric material obtained from recycled nylon shales having 90% nylon 6 are used. and 10% dirt and reinforcing contaminants. The materials are extruded using equipment as described in the U.S. Patent. No. 5, 244,614. The relative amounts of each component are 70% by weight of nylon 6 in the sheath and 30% by weight of nylon 6 recirculated in the core. The final extruder zone temperatures for each polymer are 275SC for nylon 6 and 275C for recycled nylon 6. The spin pack temperature is 270SC The polymers are delivered to the spin pack designed using thin plates such as described in U.S. Patent No. 5,458,972 so as to form a tri-lobal bi-component fiber having a primary core of concentric circular cross section and a radially elongated secondary core, of elliptical cross section in each of the fiber-trilobal legs. The fiber is cooled, stretched and textured in a continuous spinning-stretching apparatus (Rieter JO / 10). The design ratio is 2.8 and the winding speed is 2200 meters per minute.

Example 3 (Invention) It is known that the recycled polymer material will have some color variation (typically a gray-green shade) due to different colors and polymers between batches of recycled material. The recycled polymer is measured in this way for - color difference against a known color standard. Then, a specified amount of carbon black is added to the recycled polymer to correct the color to the known conventional color. The "color-leveled" recycled polymer could then be spun as a core in the fibers in accordance with - Examples 1 and 2.

Even though the invention has been described in relation to what is currently considered to be the most practical and preferred modality, it should be understood that the invention is not tailored to the described modality, but on the contrary, it is intended to cover the various Modifications and equivalent provisions included within the spirit and scope of the appended claims.

Claims (18)

1. CLAIMS: 1. - A bicomponent fiber comprised of a regenerated colored polymer core domain, and a fiber-forming polyamide sheath domain that completely surrounds the core d minum, the sheath domain being colored to a degree that the core color of Regenerated polymer is not visible.
2. 2. A fiber as in claim 1, wherein each of the core and sheath domains is nylon.
3. 3. A fiber as in claim 2, wherein the nylon is nylon-6.
4. 4. A bicomponent sheath-core fiber comprised of a core formed of a regenerated polymer having a color that deviates from a color standard, and a sheath that completely surrounds the core, wherein the core includes a leveling of the core. color in an amount sufficient to correct the color of the regenerated polymer so that it matches the standard of colo 5.- The fiber of. the rei indication 4, where the color level is carbon black. 6. A fiber as in claim 4, in the form of a concentric, triangular, bicomponent sheath-core fiber. 7. A fiber as in claim 6, wherein the nylon sheath is nylon 6 or nylon 6/6. 8. - A fiber as in claim 7, wherein the core comprises 50% by weight or more of the fiber. 9. A fiber as in claim 8, wherein the sheath comprises more than about 75% by weight of the fiber, and the core comprises less than about 25% by weight of the fiber. 10. A fiber as in claim 1 or 4, which is stretched more than 10%. 11. A fiber as in claim 1 or 4, which is a continuous, voluminous carpet fiber. 12. A fiber as in claim 1 or 4, which is a short fiber. 13.- A fiber for two-component, stretched, multilobal vai-core, comprised of a domain of polymeric nucleus, colored, regeneraod, and a polyamide fiber-forming sheath domain that completely surrounds the d-core domain, the domain of Sheath being colored to a degree that the color of the regenerated polymer core is not visible. 14. A carpet fiber as in claim 13, which is trilobal. 15. A carpet fiber as in claim 13, wherein the sheath comprises approximately 70% or more by weight of the fiber, and the core comprises approximately 30% by weight or less of the fiber. 16. A fiber for the carpet as in claim 15, wherein the pod comprises approximately 75% by weight or more of the fiber, and the core comprises approximately 25% by weight or less of the fiber. 17. A yarn comprised of a plurality of carpet fibers as in any of claims 13-16. 18. A fabric comprised of a plurality of fibers as in any of claims 1-12. 1-9.- A method for making a bicomponent fiber-which comprises directing respective melt flows of a fiber-forming polymer at least partially crystalline and a -regenerated polymer to a spinning nozzle, forming a bicomponent fiber by extruding the at least partially crystalline fiber-forming polymer and the melt flow of regenerated polymer through orifices of the spinning nozzle so that the regenerated polymer is present as a domain in the cross-section of the fiber and the polymer fiber - is present as another domain in the cross section of fiber, and then quickly cool the bicomponent fiber. 20. A method as in claim 19, further comprising the step of stretching the bicomponent fiber at least 105. 21. A method as in claim 19, wherein the regenerated polymer is recycled carpet comprised of approximately 90 % nylon-6 and approximately 10% non-polymeric contaminants. 22. A method as in claim 21, wherein the fiber-forming polymer is nylon 6. 23. A method as in claim 22, where fiber is tri-lobal. 24. A method as in claim 19, which comprises forming a concentric sheath-core bicomponent fiber, wherein the sheath comprises nylon-6 and the core comprises a regenerated, colored nylon-6. 25. A method for making a bicomponent colored fiber comprising melt spinning a fiber-forming polymer and a regenerated, colored polymer, so that the colored regenerated polymer is present as a core domain that is completely surrounded by a sheath domain of the fiber-forming polymer, and where prior to melt spinning, the sequential steps of: (I) comparing the colored regenerated polymer with a color standard are practiced; and (II) adding a color leveler to the regenerated polymer, colored in an amount sufficient to obtain a regenerated, colored polymer having a color that matches the color standard. 26. The method of claim 25, wherein the color leveler is carbon black. 27. The method of claim 25 or 26, wherein the sheath is formed of nylon 6 and the core is formed of a regenerated polymer that is recycled carpet comprised of approximately 90% nylon-6 and about 10% non-polluting contaminants.