Patent Publication Number: US-10760186-B2

Title: Manufacture of bi-component continuous filaments and articles made therefrom

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to the manufacture of bi-component continuous filaments and articles made therefrom, including yarns and fabrics, and end-use applications thereof, preferably including floor coverings such as mats, rugs, and carpets. The present invention also is disclosed in patent application 201721011143 filed in India on Mar. 29, 2017, the disclosure of which is incorporated by reference herein. 
     Continuous filaments are well known in the textile industry. A continuous filament generally comprises a polymer material that is extruded as a long fiber. Such fibers can be twisted together and heat set to form strands of yarn. In turn, the yarn can be texturized for increasing bulkiness and for better wear resistance, and often such yarn is used in carpet as an alternative to carpets made using spun yarn comprised of staple fibers. Indeed, such bulked continuous filaments used in carpets sometimes are referenced as “BCF fibers”, and advances in technology both have resulted in the ability to create filament looks that were impractical in the past, and have made filament production faster and more economical than before Styles previously made using only spun yarn now are made using BCF fibers. 
     Various types of continuous filaments have been developed over the years and have been employed for a variety of uses based on the polymers used. Early examples can be found in U.S. Pat. No. 4,075,378 and U.S. Pat. No. 4,439,487, each of which has been assigned to E. I. du Pont de Nemours and Company. A bi-component continuous filament is a continuous filament made by extruding two different components that together form the long fiber; the two components generally comprise two different polymer materials that are extruded together. Some existing bi-component filaments have been designed by employing a sheath-core arrangement, in which a lower melting temperature polymer is used in forming a sheath component and a higher melting temperature polymer is used in forming a core component of the bi-component continuous filament. Bi-component continuous filaments made in this manner have been used in nonwoven webs to thermally bond the webs together. 
     Some existing yarns made from bi-component continuous filaments consist of a raw white (i.e., color-free) polymer component that has a fine count in texturized polyester pre-oriented yarn, which is typically made by spinning polyester chips of polyethylene terephthalate (PET). Polymer components of bi-component continuous filaments also can be dyed at some point after the bi-component continuous filament has been spun. 
     Unfortunately, many articles made from bi-component continuous filaments and yarns thereof undergo delamination over time, a degradation in which the polymer components begin to separate from one another. This especially occurs when high levels of wear and tear are involved, affecting integrity and long-term durability of such articles. 
     It is believed that one or more needs exist for improvement in the field of making bi-component continuous filaments and articles made therefrom, and for durable, resilient and/or color-fast bi-component continuous filaments and articles made therefrom that are capable of use across a wide range of articles including textile products, and particularly, floor coverings. These, and other needs, are believed to be addressed by one or more preferred embodiments of the present invention. 
     SUMMARY OF THE INVENTION 
     The present invention includes many aspects and features. Moreover, while many aspects and features relate to, and are described in, the context of floor coverings, the present invention is not limited to use only in such context, as will become apparent from the following summaries and detailed descriptions of aspects, features, and one or more embodiments of the present invention. 
     Accordingly, in an aspect of the present invention, a bi-component continuous filament comprises a first polymer component; a second polymer component; and a binding agent adhering the first polymer component to the second polymer component along a length of the filament such that the filament has a generally uniform cross-sectional shape along the length. 
     In feature of this aspect, the first and second polymer components are extruded, with the first polymer component forming a sheath and the second polymer component forming a core that is surrounded by the sheath. 
     In another feature, the binding agent comprises a polyolefin modified by an acid anhydride. 
     In another aspect, a bi-component continuous filament comprises a first polymer component that forms a sheath of the continuous filament; a second polymer component that forms a core of the continuous filament that is surrounded by the sheath; and a binding agent adhering the first polymer component to the second polymer component along a length of the filament such that the filament has a generally uniform cross-sectional shape along the length, wherein the binding agent comprises a polyolefin modified by an acid anhydride. 
     In a feature, the first polymer component comprises a polyamide. 
     In a feature, the first polymer component comprises a polyolefin. 
     In a feature, the first polymer component comprises a polyester. 
     In a feature, the second polymer component comprises a polyamide. 
     In a feature, the second polymer component comprises a polyolefin. 
     In a feature, the second polymer component comprises a polyester. 
     In a feature, the polyolefin modified by the acid anhydride comprises polyethylene (PE). 
     In a feature, the polyolefin modified by the acid anhydride comprises ethylene-vinyl acetate (EVA). 
     In a feature, the polyolefin modified by the acid anhydride comprises polypropylene (PP). 
     In a feature, the acid anhydride comprises maleic anhydride. 
     In a feature, each of the first and second polymer components is solution-dyed. 
     In a feature, one but not both the first and second polymer components is solution-dyed. 
     In a feature, at least one of the first and second polymer components is solution-dyed with a pigment. The pigment may be in an organic or inorganic form. 
     In a feature, at least one of the first and second polymer components is solution-dyed with a pigment and a solvent. 
     In a feature, the second polymer component forming the core of the bi-component continuous filament comprises a recycled polyamide. 
     In a feature, the second polymer component forming the core of the bi-component continuous filament comprises a virgin polyester. 
     In a feature, the second polymer component forming the core of the bi-component continuous filament comprises a recycled polyester. 
     In another feature, the first polymer component comprises a polyamide in cationic form. 
     In another feature, the first polymer component comprises a polyolefin in cationic form. 
     In another feature, the first polymer component comprises a polyester in cationic form. 
     In a feature, at least one of the first and second polymer components is raw white. 
     In a feature, the sheath has a tri-lobal or generally circular cross-sectional shape, and wherein the core has a generally circular cross-sectional shape that is generally arranged concentrically relative to the sheath. 
     In a feature, the sheath has a tri-lobal or generally circular cross-sectional shape, and wherein the core has a generally circular cross-sectional shape that is generally arranged eccentrically relative to the sheath. 
     In a feature, at least one of the first and second polymer components comprises polyolefin, and wherein the polyolefin comprises polyethylene (PE). 
     In a feature, at least one of the first and second polymer components comprises polyolefin, and wherein the polyolefin comprises ethylene-vinyl acetate (EVA). 
     In a feature, at least one of the first and second polymer components comprises polyolefin, and wherein the polyolefin comprises polypropylene (PP). 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 6. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 6,6. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 7. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 6,10. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 6,12. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 12. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 46. 
     In a feature, at least one of the first and second polymer components comprises polyamide, and wherein the polyamide comprises nylon 1212. 
     In a feature, at least one of the first and second polymer components comprises polyester, and wherein the polyester comprises polyethylene terephthalate (PET). 
     In a feature, at least one of the first and second polymer components comprises polyester, and wherein the polyester comprises polybutylene terephthalate (PBT). 
     In a feature, at least one of the first and second polymer components comprises polyester, and wherein the polyester comprises polytrimethylene terephthalate (PTT). 
     In a feature, the polymer of the first polymer component is different than the polymer of the second polymer component. 
     In a feature, the bi-component continuous filament exhibits a denier per filament (DPF) ratio measuring from approximately 2 DPF to approximately 30 DPF. 
     In a feature, the bi-component continuous filament exhibits a weight measuring between approximately 500 denier to approximately 3500 denier. 
     In another aspect, a method of making a bi-component continuous filament comprises the steps of: providing in a first mixer a first polymer comprising a polyamide, a polyolefin, or a polyester; providing in a second mixer both a binding agent comprising a polyolefin modified by an acid anhydride, and a second polymer comprising a polyamide, a polyolefin, or a polyester; heating the first polymer to form a first polymer melt; heating the second polymer to form a second polymer melt; solution dyeing the first polymer melt by adding a first pigment and mixing the first polymer melt and the first pigment to form a first mixture; solution dyeing the second polymer melt by adding a second pigment and mixing the second polymer melt and the second pigment to form a second mixture; extruding using a spinneret, from the first mixture, a first polymer component in the form of a sheath, and from the second mixture, a second polymer component in the form of a core that is surrounded by the sheath, wherein a bi-component continuous filament is obtained, and wherein the binding agent adheres the first polymer component to the second polymer component along a length of the bi-component continuous filament such that the bi-component continuous filament has a generally uniform cross-sectional shape along the length; and heat setting the bi-component continuous filament comprising dry heat setting, steam heat setting, or both. 
     In another aspect, a method of making an article from bi-component continuous filaments comprises the steps of: providing in a first mixer a first polymer comprising a polyamide, a polyolefin, or a polyester; providing in a second mixer both a binding agent comprising a polyolefin modified by an acid anhydride, and a second polymer comprising a polyamide, a polyolefin, or a polyester; heating the first polymer to form a first polymer melt; heating the second polymer to form a second polymer melt; solution dyeing the first polymer melt by adding a first pigment and mixing the first polymer melt and the first pigment to form a first mixture; solution dyeing the second polymer melt by adding a second pigment and mixing the second polymer melt and the second pigment to form a second mixture; extruding using a spinneret, from the first mixture, a first polymer component in the form of a sheath, and from the second mixture, a second polymer component in the form of a core that is surrounded by the sheath, whereby bi-component continuous filaments are obtained, and wherein the binding agent adheres the first polymer component to the second polymer component along a length of each bi-component continuous filament such that each bi-component continuous filament has a generally uniform cross-sectional shape along its length; twisting the bi-component continuous filaments; texturizing the bi-component continuous filaments; and heat setting the bi-component continuous filaments comprising dry heat setting, steam heat setting, or both. 
     In another aspect, an article comprises bi-component continuous filaments of or made according to one or more of the foregoing aspects and features. 
     In another aspect, bulk continuous filament (BCF) fibers comprise bi-component continuous filaments of or made according to one or more of the foregoing aspects and features. 
     In another aspect, a woven textile product comprises bi-component continuous filaments of or made according to one or more of the foregoing aspects and features. 
     In another aspect, a tufted textile product comprises bi-component continuous filaments of or made according to one or more of the foregoing aspects and features. 
     In another aspect, a floor covering comprises bi-component continuous filaments of or made according to one or more of the foregoing aspects and features. 
     In addition to the foregoing aspects and features of the present invention, it should be noted that the present invention further encompasses the various logical combinations and subcombinations of such aspects and features. Thus, for example, claims in this or a divisional or continuing patent application or applications may be separately directed to any aspect, feature, or embodiment disclosed herein, or combination thereof, without requiring any other aspect, feature, or embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more preferred embodiments of the present invention now will be described in detail with reference to the accompanying drawings, wherein the same elements are referred to with the same reference numerals. 
         FIG. 1  is a schematic cross-sectional view of an embodiment of a bi-component filament, in accordance with one or more aspects of the present invention, depicting the bi-component filament as having a circular cross-sectional shape with the polymer components in a concentrically-arranged sheath-core relationship. 
         FIG. 2  is a schematic cross-sectional view of an embodiment of a bi-component filament, in accordance with one or more aspects of the present invention, depicting the bi-component filament as having a circular cross-sectional shape with the polymer components in an eccentrically-arranged sheath-core relationship. 
         FIGS. 3 and 4  are each schematic cross-sectional views of an embodiment of a bi-component filament, in accordance with one or more aspects of the present invention, depicting the bi-component filament as having a tri-lobal cross-sectional shape with the polymer components in a sheath-core relationship. 
         FIGS. 5A-5D  are images depicting a plurality of bi-component filament, arranged in a sheath-core relationship, having parameters similar to that of the bi-component filament of  FIG. 3 . 
         FIG. 6  is a schematic cross-sectional view of an embodiment of a bi-component filament, in accordance with one or more aspects of the present invention, depicting the bi-component filament as having a circular cross-sectional shape with the polymer components in a side-by-side relationship. 
     
    
    
     DETAILED DESCRIPTION 
     As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art (“Ordinary Artisan”) that the invention has broad utility and application. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the invention. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure of the invention. Furthermore, an embodiment of the invention may incorporate only one or a plurality of the aspects of the invention disclosed herein; only one or a plurality of the features disclosed herein; or combination thereof. As such, many embodiments are implicitly disclosed herein and fall within the scope of what is regarded as the invention. 
     Accordingly, while the invention is described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present invention, and is made merely for the purposes of providing a full and enabling disclosure of the invention. The detailed disclosure herein of one or more embodiments is not intended, nor is to be construed, to limit the scope of patent protection afforded the invention in any claim of a patent issuing here from, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection afforded the invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself. 
     Thus, for example, any sequence(s) and/or temporal order of steps of various processes or methods that are described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal order, the steps of any such processes or methods are not limited to being carried out in any particular sequence or order, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and orders while still falling within the scope of the invention. Accordingly, it is intended that the scope of patent protection afforded the invention is to be defined by the issued claim(s) rather than the description set forth herein. 
     Additionally, it is important to note that each term used herein refers to that which the Ordinary Artisan would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein—as understood by the Ordinary Artisan based on the contextual use of such term—differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the Ordinary Artisan should prevail. 
     With regard solely to construction of any claim with respect to the United States, no claim element is to be interpreted under 35 U.S.C. 112(f) unless the explicit phrase “means for” or “step for” is actually used in such claim element, whereupon this statutory provision is intended to and should apply in the interpretation of such claim element. With regard to any method claim including a condition precedent step, such method requires the condition precedent to be met and the step to be performed at least once during performance of the claimed method. 
     Furthermore, it is important to note that, as used herein, “a” and “an” each generally denotes “at least one,” but does not exclude a plurality unless the contextual use dictates otherwise. Thus, reference to “a picnic basket having an apple” describes “a picnic basket having at least one apple” as well as “a picnic basket having apples.” In contrast, reference to “a picnic basket having a single apple” describes “a picnic basket having only one apple.” 
     When used herein to join a list of items, “or” denotes “at least one of the items,” but does not exclude a plurality of items of the list. Thus, reference to “a picnic basket having cheese or crackers” describes “a picnic basket having cheese without crackers”, “a picnic basket having crackers without cheese”, and “a picnic basket having both cheese and crackers.” When used herein to join a list of items, “and” denotes “all of the items of the list.” Thus, reference to “a picnic basket having cheese and crackers” describes “a picnic basket having cheese, wherein the picnic basket further has crackers,” as well as describes “a picnic basket having crackers, wherein the picnic basket further has cheese.” 
     Referring now to the drawings, one or more preferred embodiments of the invention are next described. The following description of one or more preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its implementations, or uses. 
       FIG. 1  is a schematic cross-sectional view of an embodiment of a bi-component filament  10 , in accordance with one or more aspects of the present invention, depicting the bi-component filament  10  as having a circular cross-sectional shape with the polymer components in a concentrically-arranged sheath-core relationship, and  FIG. 2  is a schematic cross-sectional view of an embodiment of a bi-component filament  110 , in accordance with one or more aspects of the present invention, depicting the bi-component filament  110  as having a circular cross-sectional shape with the polymer components in an eccentrically-arranged sheath-core relationship. In each of  FIGS. 1 and 2 , a first polymer component  12 , 112  entirely surrounds a second polymer component  14 , 114  (cross-sectionally) so that the first polymer component  12 , 112  forms a sheath around the second polymer component  14 , 114 , which forms a core. In a preferred embodiment, the first polymer component  12 , 112  is different from the second polymer component  14 , 114 , thereby imparting the bi-component filament  10 , 110  with attributes of each filament individually as well as attributes that might arise by the pairing of the selected polymer components. 
     In  FIG. 1 , the first and second polymer components  12 , 14  are generally concentrically arranged, with the core disposed at a generally central location within the sheath. It should be noted that, though each of the polymer components  12 , 14  of the bi-component filament  10  of  FIG. 1  is depicted as having a generally circular cross-sectional shape, it is contemplated that either or both polymer components can be formed to have any of a variety of other non-circular cross-sectional shapes, including, but not limited to, elliptical shapes, tri-lobal shapes, and the like. 
     In  FIG. 2 , the first and second polymer components  112 , 114  are eccentrically arranged, with the core disposed at a generally non-central (i.e., off center) location within the sheath. As with  FIG. 1 , it should be noted that, though each of the polymer components  112 , 114  of the bi-component filament  110  of  FIG. 2  is depicted as having a generally circular cross-sectional shape, it is contemplated that either or both polymer components can be formed to have any of a variety of other non-circular cross-sectional shapes, including, but not limited to, elliptical shapes, tri-lobal shapes, and the like. 
       FIGS. 3 and 4  are each schematic cross-sectional views of an embodiment of a bi-component filament  210 , 310 , in accordance with one or more aspects of the present invention, depicting the bi-component filament  210 , 310  as having a tri-lobal cross-sectional shape with the polymer components in a sheath-core relationship. In each of  FIGS. 3 and 4 , a first polymer component  212 , 312  entirely surrounds a second polymer component  214 , 314  (cross-sectionally) so that the first polymer component  212 , 312  forms a sheath around the second polymer component  214 , 314 , which forms a core. In a preferred embodiment, the first polymer component  212 , 312  is different from the second polymer component  214 , 314 , thereby imparting the bi-component filament  210 , 310  with attributes of each filament individually as well as attributes that might arise by the pairing of the selected polymer components. 
     In  FIG. 3 , each of the polymer components  212 , 214  of the bi-component filament  210  of  FIG. 3  is depicted as having a tri-lobal cross-sectional shape. Although the arrangement of the tri-lobal cross-sectional shape of the core relative to the cross-sectional shape of the sheath is shown as being generally symmetric, an asymmetrical arrangement of the core relative to the sheath is likewise contemplated. A tri-lobal cross-sectional shape for each of the first and second polymer component  212 , 214  can provide increased surface-to-surface interface between the sheath and the core, thereby enhancing the opportunity for effective adhesion between the polymer components  212 , 214 . 
     In  FIG. 4 , the first polymer component  312  is depicted as having a tri-lobal cross-sectional shape, and the second polymer component  314  is depicted as having a generally circular shape. As should be clear, it is contemplated that the cross-sectional shape of the sheath and the core of bi-component filaments in accordance with one or more aspects of the present invention are not required to embody the same cross-sectional shape. It is contemplated that cross-sectional shapes of the sheath and the core can be selected to provide resulting bi-component filaments with physical attributes that might be well-suited to a particular end-use application. 
     With regard to each of the bi-component filaments  10 , 110 , 210 , 310  shown and described in connection with each of  FIGS. 1-4 , a wide variety of different polymers can be selected for implementation as the polymer components. Polymers can be selected to impart the resulting bi-component with desired physical attributes, such as resiliency, durability and/or strength, which may be advantageous for a particular end-use application. 
     In at least some embodiments, the first polymer component  12 , 112 , 212 , 312 , which component is ultimately implemented as the sheath in the resultant bi-component filaments  10 , 110 , 210 , 310 , includes a polyamide, a polyolefin, or polyester. Other classes of polymers commonly used in the manufacture of woven textile materials and products are likewise contemplated. A polyamide that can be selected as the first polymer component  12 , 112 , 212 , 312  includes any of a variety of chained polymers having amide linkages, but is not limited to, nylon 6, nylon 6,6, nylon 7, nylon 6,10, nylon 6,12, nylon 12, nylon 46 or nylon 1212. A polyolefin that can be selected as the first polymer component  12 , 112 , 212 , 312  includes, but is not limited to, polyethylene (PE), ethylene-vinyl acetate (EVA), or polypropylene (PP). A polyester that can be selected as the first polymer component  12 , 112 , 212 , 312  includes, but is not limited to, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). In a preferred embodiment, the first polymer component  12 , 112 , 212 , 312  includes nylon 6. In another preferred embodiment, the first polymer component  12 , 112 , 212 , 312  includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     In at least some embodiments, the second polymer component  14 , 114 , 214 , 314 , which component is ultimately implemented as the core in the resultant bi-component filaments  10 , 110 , 210 , 310 , includes a polyamide, a polyolefin, or a polyester. Other classes of polymers commonly used in the manufacture of woven textile materials and products are likewise contemplated. A polyamide that can be selected as the second polymer component  14 , 114 , 214 , 314  includes any of a variety of chained polymers having amide linkages, but is not limited to, nylon 6, nylon 6,6, nylon 7, nylon 6,10, nylon 6,12, nylon 12, nylon 46 or nylon 1212. A polyolefin that can be selected as the second polymer component  14 , 114 , 214 , 314  includes, but is not limited to, polyethylene (PE), ethylene-vinyl acetate (EVA), or polypropylene (PP). A polyester that can be selected as the second polymer component  14 , 114 , 214 , 314  includes, but is not limited to, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). In a preferred embodiment, the second polymer component  14 , 114 , 214 , 314  includes polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     In at least some embodiments, bi-component filaments  10 , 110 , 210 , 310  include one or more binding agents to facilitate effective adhesion between the first and second polymer components along their respective lengths. It is contemplated that a binding agent can be added to either or both of the and second polymer components when in chip form, prior to heating and extrusion. In a preferred embodiment, the binding agent is mixed with the chip form of the second polymer component  14 , 114 , 214 , 314 , which ultimately is used to form the core of the resulting bi-component filaments  10 , 110 , 210 , 310 . Once thoroughly mixed, the binding agent is spun (i.e., extruded) with either or both of the and second polymer components so that the first and second polymer components can be bound together in such a way that the resulting bi-component filaments  10 , 110 , 210 , 310  are less likely to undergo delamination (i.e., separation of the first and second polymer components) during preparation and/or use of a textile product utilizing the filament. 
     It is contemplated that a wide variety of different materials can be used as a binding agent in connection with generation of bi-component filaments  10 , 110 , 210 , 310  in accordance with one or more aspects of the present invention. In one contemplated embodiment, the binding agent includes a polyolefin modified by an organic acid anhydride. Polyolefins capable of modification by an organic acid anhydride to function as a binding agent include, but are not limited to, polyethylene (PE), ethylene-vinyl acetate (EVA), and polypropylene (PP). An organic acid anhydride for modifying a polyolefin to function as a binding agent includes, but is not limited to, maleic anhydride. 
     To illustrate effectiveness of the inclusion of a binding agent in the generation of bi-component filaments in accordance with one or more aspects of the present invention,  FIGS. 5A-5D  are images depicting a plurality of bi-component filaments, arranged in a sheath-core relationship, having parameters similar to that of the bi-component filaments  210  of  FIG. 3 . The test data associated with the images of  FIGS. 5A-5D  are summarized below in Table 1. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Bi-Component 
                 Denier/ 
                 % 
                   
                 % Boiling Water 
                 % Crimp 
               
               
                 Image 
                 Filament 
                 filament 
                 Elongation 
                 Tenacity 
                 Shrinkage 
                 Contraction 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 FIG. 
                 Nylon 6/PET 
                 1200/60 
                 37.88 
                 3 
                 2.5 
                 20.41 
               
               
                 5A 
                 (no Binding Agent) 
               
               
                 FIG. 
                 Nylon 6/PET 
                 1200/60 
                 37.64 
                 3.85 
                 1.25 
                 20.58 
               
               
                 5B 
                 (50/50) 
               
               
                   
                 (with Binding 
               
               
                   
                 Agent) 
               
               
                 FIG. 
                 Nylon 6/PET 
                 1200/60 
                 35.39 
                 3.39 
                 0.92 
                 19.27 
               
               
                 5C 
                 (33/67) 
               
               
                   
                 (with Binding 
               
               
                   
                 Agent) 
               
               
                 FIG. 
                 Nylon 6/PET 
                 1200/60 
                 33.61 
                 3.55 
                 1.81 
                 21.64 
               
               
                 5D 
                 (67/33) 
               
               
                   
                 (with Binding 
               
               
                   
                 Agent) 
               
               
                   
               
            
           
         
       
     
       FIG. 5A  depicts a cross-sectional view of bi-component filaments, with a tri-lobal cross-sectional shape, having a sheath formed of a polyamide that includes nylon 6 and a core formed of a polyester that includes polyethylene terephthalate (PET). The bi-component filament depicted in  FIG. 5A  does not include a binding agent. 
     Each of  FIGS. 5B-5D  likewise depicts a cross-sectional view of bi-component filament, with a tri-lobal cross-sectional shape, having a sheath formed of a polyamide that includes nylon 6 and a core formed of a polyester that includes polyethylene terephthalate (PET). The percentage of each polymer component relative to the whole varies across the three samples, as presented in the second column of Table 1. Each of the samples of  FIGS. 5B-5D  was prepared using a binding agent as described above. 
     As summarized in Table 1, the bi-component filament samples of  FIGS. 5B-5D  exhibit higher tenacity levels (i.e., strength) than the bi-component filament sample of  FIG. 5A , which was prepared without a binding agent. As further shown in Table 1, the bi-component filament samples of  FIGS. 5B-5D  maintain relatively high elongation percent in conjunction with increased tenacity. Accordingly, the bi-component filament samples of  FIGS. 5B-5D  support an increase in overall strength with the use of a binding agent as described above. 
     Furthermore, with reference to  FIG. 5A  (and by comparison of  FIG. 5A  with  FIGS. 5B-5D ), some bi-component filaments of  FIG. 5A  exhibit delamination between the sheath  512  and the core  514 . In particular,  FIG. 5A  illustrates that gaps  518  have already formed between the sheath  512  and the core  514 , where the polymer components are no longer adhered to one another. In  FIG. 5B  (as well as  FIGS. 5C and 5D ), by comparison, the bi-component filaments exhibit a high degree of lamination, with little to no gaps, where the binding agent has effectively bound the sheath  612  and the core  614  together along their respective lengths. 
     In at least some embodiments, either or both of the first and second polymer components of bi-component filaments  10 , 110 , 210 , 310  is solution-dyed (i.e., dope-dyed) to enhance certain physical attributes of the resulting bi-component filaments. Because many polymers are initially color-free (i.e., raw white), polymers can be treated using a solution dyeing process prior to spinning a bi-component filament. In this regard, rather than dyeing the resulting filament, the polymer components themselves can be permeated with a desired pigment via solution dyeing so that the color exists in the extruded polymer mix. Filaments prepared using a solution dyeing process have demonstrated enhanced ability to retain color (i.e., color fastness). 
     In one contemplated form of solution dyeing usable to generate bi-component filaments  10 , 110 , 210 , 310  in accordance with one or more aspects of the present invention, the solution is prepared using a pigment dyestuff to add a desired color to the polymer mix. Here, the pigment is typically a pure color pigment that is added during the melt stage and extruded with either or both polymer components to deliver a spun filament exhibiting the selected color. It is contemplated that the pigment can be in an organic or an inorganic form, as might be desired. In many cases, use of a pure color pigment in connection with solution dyeing results in filaments with strong, vivid color, although a range of color variability (i.e., subtle changes of hues) can sometimes be difficult to achieve. 
     In another contemplated form of solution dyeing usable to generate bi-component filaments  10 , 110 , 210 , 310  in accordance with one or more aspects of the present invention, the solution is prepared using each of a pigment dyestuff and a solvent. A solvent added to the solution dyeing process can introduce added strength to an extruded polymer. In addition, inclusion of a solvent can facilitate enhanced color variability. In other words, the solvent can soften the effect of the pure color pigment, standing alone, so that a wider range of color shades and hues can be obtained in an extruded polymer. 
     It is contemplated that either the first component, the second component or both the first and second components can be treated via a solution dyeing process. Furthermore, it is contemplated that, to the extent that a natural white color is preferred, neither the first polymer component nor the second polymer component is solution dyed so as to preserve the raw white characteristic of color-free polymer. In a preferred embodiment, each of the first and second polymer components is solution-dyed prior to extrusion—either using a pigment alone or using a pigment in combination with a solvent. In this regard, it is contemplated that each of the first and second polymer components can be treated using the same solution dyeing process (i.e., using the same solvent and/or pigment) or using a different solution dyeing processes (i.e., using different solvents and/or pigments for each polymer component). In this latter regard, a resultant bi-component filament  10 , 110 , 210 , 310  can exhibit a sheath of one color and a core of a different color. 
     EXAMPLES 
     It is contemplated that the examples discussed hereinbelow may be implemented with respect to any of the bi-component filament shapes and/or arrangements discussed hereinabove in connection with  FIGS. 1-4 . 
     Example 1 
     In one contemplated bi-component filament in accordance with one or more aspects of the present invention, first and second polymer components of the bi-component filament are arranged in a sheath-core relationship. In this example, each of the first polymer component (i.e., the sheath) and the second polymer component (i.e., the core) is solution-dyed during or prior to the extrusion process. The solution-dyeing process in this example includes: (a) solution dyeing with a pigment (using a pigment in either an organic or an inorganic form); or (b) solution dyeing with a combination of a pigment and a solvent. 
     In Example 1, it is contemplated that the first polymer component (i.e., the sheath) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Furthermore, in Example 1, it is contemplated that the second polymer component (i.e., the core) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Example 2 
     In another contemplated bi-component filament in accordance with one or more aspects of the present invention, first and second polymer components of the bi-component filament are arranged in a sheath-core relationship. Although not required, one or both of the first polymer component (i.e., the sheath) and the second polymer component (i.e., the core) are solution-dyed during or prior to the extrusion process. The solution-dyeing process in this example includes: (a) solution dyeing with a pigment (using a pigment in either an organic or an inorganic form); or (b) solution dyeing with a combination of a pigment and a solvent. Alternatively, it is contemplated that each of the first polymer component and the second polymer can be color-free (i.e., raw white). It is further contemplated that the first polymer component (i.e. the sheath) can be solution-dyed in accordance with one of the above-described processes, while the second polymer component (i.e., the core) is color-free, or that the second polymer component (i.e., the core) can be solution-dyed in accordance with one of the above-described processes, while the first polymer component (i.e., the sheath) is color-free. 
     In Example 2, a binding agent is mixed with one or both of the and second polymer components. As the polymers are extruded into the bi-component continuous filament, the binding agent facilitates strong adhesion qualities between the first and second polymer components. The binding agent includes, for example, a polyolefin modified by maleic anhydride. 
     Furthermore, in Example 2, it is contemplated that the first polymer component (i.e., the sheath) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Furthermore, in Example 2, it is contemplated that the second polymer component (i.e., the core) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Example 3 
     In another contemplated bi-component filament in accordance with one or more aspects of the present invention, first and second polymer components of the bi-component filament are arranged in a sheath-core relationship. In this example, each of the first polymer component (i.e., the sheath) and the second polymer component (i.e., the core) is solution-dyed during or prior to the extrusion process. The solution-dyeing process in this example includes: (a) solution dyeing with a pigment (using a pigment in either an organic or an inorganic form); or (b) solution dyeing with a combination of a pigment and a solvent. 
     In Example 3, it is contemplated that the first polymer component (i.e., the sheath) includes a polyamide in cationic form, a polyolefin in cationic form, or a polyester in cationic form. The polyamide includes, for example, a cationic form of nylon 6. The polyolefin includes, for example, a cationic form of polypropylene (PP). The polyester includes, for example, a cationic form of polyethylene terephthalate (PET), a cationic form of polybutylene terephthalate (PBT), or a cationic form of polytrimethylene terephthalate (PTT). 
     Furthermore, in Example 3, it is contemplated that the second polymer component (i.e., the core) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Example 4 
     In still another contemplated bi-component filament in accordance with one or more aspects of the present invention, first and second polymer components of the bi-component filament are arranged in a sheath-core relationship. Although not required, one or both of the first polymer component (i.e., the sheath) and the second polymer component (i.e., the core) can be solution-dyed during or prior to the extrusion process. The solution-dyeing process in this example includes: (a) solution dyeing with a pigment (using a pigment in either an organic or an inorganic form); or (b) solution dyeing with a combination of a pigment and a solvent. Alternatively, it is contemplated that each of the first polymer component and the second polymer can be color-free (i.e., raw white). It is further contemplated that the first polymer component (i.e. the sheath) can be solution-dyed in accordance with one of the above-described processes, while the second polymer component (i.e., the core) is color-free, or that the second polymer component (i.e., the core) can be solution-dyed in accordance with one of the above-described processes, while the first polymer component (i.e., the sheath) is color-free. 
     In Example 4, a binding agent is mixed with one or both of the and second polymer components. As the bi-component filament is extruded, the binding agent facilitates strong adhesion qualities between the first and second polymer components. The binding agent includes, for example, a polyolefin modified by maleic anhydride. 
     Furthermore, in Example 4, it is contemplated that the first polymer component (i.e., the sheath) includes a polyamide, a polyolefin, or a polyester. The polyamide includes, for example, nylon 6. The polyolefin includes, for example, polypropylene (PP). The polyester includes, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT). 
     Furthermore, in Example 4, it is contemplated that the second polymer component (i.e., the core) includes a recycled polyamide or a recycled polyester. The polyamide includes, for example, a recycled form of nylon 6. The polyester includes, for example, a recycled form of polyethylene terephthalate (PET). 
     Turning now to  FIG. 6 , a schematic cross-sectional view of an embodiment of a bi-component filament  410 , in accordance with one or more aspects of the present invention, is shown. Here, the bi-component filament  410  has a generally circular cross-sectional shape with the polymer components arranged in a side-by-side relationship. As shown in  FIG. 6 , bi-component filaments in accordance with one or more aspects of the present invention are not limited to the polymer components being arranged in a sheath-core relationship. In  FIG. 6 , two different polymer components  416 , 418  are shown side by side, and adhered together, to form a single bi-component filament  410  having a generally circular cross-sectional shape. It should be noted that, though the bi-component filament  410  of  FIG. 6  is depicted as having a generally circular cross-sectional shape, filaments with non-circular cross-sectional shapes (e.g., elliptical, tri-lobal, and the like) are likewise contemplated. Furthermore, in at least some contemplated embodiments, a bi-component filament with polymer components arranged in a side-by-side relationship, as in  FIG. 6 , can be symmetrically arranged. In other contemplated embodiments, a bi-component filament with polymer components arranged in a side-by-side relationship can be asymmetrically arranged. 
     Although not specifically depicted here, it is further contemplated that the polymer components of bi-component filaments in accordance with one or more aspects of the present invention may exhibit matrix-fibril type structure, whereby filaments of one polymer component are dispersed in a matrix made using another polymer component, or the polymer components of bi-component filaments in accordance with one or more aspects of the present invention may be arranged in a segmented pie-chart (or citrus) type structure. It is contemplated that these other types of bi-component filament arrangements can have circular or non-circular arrangements, as might be preferred. It is further contemplated that these other types of bi-component filament arrangements can have symmetrical or asymmetrical arrangements, as might be preferred. 
     In a method of generating bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention, first and second polymer components, as described in connection with  FIGS. 1-4 and 6 , are selected for inclusion in a bi-component filament. Though the polymer components often exist in a chip or pellet form, other forms of polymer components are contemplated. In a contemplated method, the first and second polymer components are mixed independently of one another. A binding agent, as described hereinabove, can be included in the polymer mix of one or both of the and second polymer components. In a contemplated embodiment, the binding agent is mixed with the second polymer component, which, in  FIGS. 1-4 , forms the core of the resulting bi-component filament. 
     Either or both of the and second polymer components can be solution-dyed prior to spinning. In contemplated embodiments, the solution dyeing process includes a pigment or each of a pigment and a solvent. As discussed hereinabove, solution dyeing the polymer components prior to spinning enables coloration of the polymer components (across a wide spectrum of colors, particularly when a solvent is included in the solution dyeing process). The solution-dyeing process can also enhance strength and durability in the polymer components so as to impart the resulting bi-component filament with desirable attributes for various end-use applications. 
     Each polymer mix is heated and stirred so that each of the first and second polymer components forms a melt that is ready for extrusion via a spinneret. The first and second polymer melts are fed through a spinneret selected to yield a bi-component filament  10 , 110 , 210 , 310 , 410  of a particular cross-sectional shape. After spinning, the resulting bi-component filament  10 , 110 , 210 , 310 , 410  can be further treated and/or texturized for implementation across a wide range of different end-use applications. The resulting filament further can be heat set, including, but not limited to, dry heat setting, steam heat setting, or a combination of both. 
     In one contemplated embodiment, the resulting bi-component filament  10 , 110 , 210 , 310 , 410  can be texturized to form bulk continuous filament suitable for tufting and weaving into floor coverings, such as carpets, or other textile products where durability, strength and/or color-fastness may be advantageous. In further preparation for end-use applications, bulk continuous filament bundles of the bi-component filaments  10 , 110 , 210 , 310 , 410  can be intermingled with two or three bundles of the same color or a different color. 
     Additionally, or alternatively, the resulting bi-component filament  10 , 110 , 210 , 310 , 410  can be cable formed, whereby the filaments exhibit a pile construction with chunky tufts and longer pile height, or twist and heat set formed, whereby the filaments are twisted together and then heat set to help the twisted bundle stay intact and increase resistance to pile crush. Where bi-component filaments are twisted, it is contemplated that single or multiple bundles of bulk continuous filaments (e.g., one, two or three bundles) of the same or different color can be twisted to satisfy the demands of various end-use applications. In this regard, it is contemplated that twisting can range from zero turns per meter up to approximately 300 turns per meter. Likewise, where bi-component filaments are heat set, it is contemplated that single or multiple bundles of bulk continuous filaments (e.g., one, two or three bundles) of the same or different color can be heat set to satisfy the demands of various end-use applications. Heat setting can afford the filaments with enhanced dimensional stability as well as other desirable attributes, such as wrinkle resistance and/or temperature resistance. It is contemplated that heat setting can be accomplished by steam heating, by dry heating or by a combination of steam and dry heating. 
     In contemplated embodiments, bulk continuous filament generated using bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention exhibits a denier per filament (DPF) ratio measuring from approximately 2 DPF to approximately 30 DPF. Furthermore, in contemplated embodiments, bulk continuous filament generated using bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention exhibits a weight measuring between approximately 500 denier to approximately 3500 denier. 
     Bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention have broad utility across a range of end-use textile applications. In at least some embodiments, a polyamide sheath can provide a good visual appeal to pile change and, as such, the bi-component filament is well-suited for use in floor covering products. Furthermore, in at least some embodiments, a polyester or a polyolefin (e.g., polypropylene) core can provide enhanced moisture-repelling properties so that textile products incorporating such filaments are more durable and are quick-drying. 
     In various contemplated embodiments, bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention can be woven for production of any of a wide range of floor and surface coverings, including, but not limited to, door mats, bath rugs, area rugs, accent rugs, carpet tile rugs, broadloom carpet, automotive floor mats, automotive covering, automotive internal floor covering. It is further contemplated that bi-component filaments  10 , 110 , 210 , 310 , 410  in accordance with one or more aspects of the present invention may likewise be implemented in textile products such as sheeting, towels and other bed and bathroom textile needs. 
     Based on the foregoing description, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those specifically described herein, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing descriptions thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to one or more preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purpose of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended to be construed to limit the present invention or otherwise exclude any such other embodiments, adaptations, variations, modifications or equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.