Abstract: Multicomponent fibers and methods of producing the same are provided such that an inter-domain boundary layer is interposed between distinct domains formed of incompatible polymers so as to minimize (if not eliminate entirely) separation of the domains at their interfacial boundary. The polymer forming the inter-domain boundary layer therefore is provided so as to be compatible with the otherwise incompatible polymers forming each of the domains between which it is interposed.

Abstract: Bicomponent fibers of different cross-sections may be formed without changing the geometry of the spinneret orifices. More specifically, at least two polymers are co-melt-spun through an orifice of fixed geometry so as to achieve a bicomponent fiber having a desired cross-section. In order to change to a bicomponent fiber having a cross-section which is different, therefore, at least one of (1) the differential relative viscosity, (2) the relative proportions of the first and/or second polymers, and (3) the cross-sectional bicomponent distribution of the first and second polymers, is changed. In such a manner, therefore, a wide variety of bicomponent fibers having different cross-sectional geometries may be produced without changing the fixed geometry orifice through which the polymers are co-melt-spun. Thus, bicomponent fiber cross-sections may be "engineered" to suit a variety of needs without necessarily shutting down production equipment in order to change spinnerets.

Abstract: Novel bicomponent fibers have a polyamide domain and a contaminant-containing polymer domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and the contaminant-containing polymer constitutes the core. Surprisingly, even though the core is formed of a contaminant-containing polymer (which is difficultly spinnable), the bicomponent fibers are readily spinnable and exhibit properties which are comparable in many respects to fibers formed from 100% polyamide. Preferably, the fibers are concentric sheath-core bicomponent fibers having an uncontaminated nylon-6 sheath and a core formed from nylon-6 having a relatively high level of contamination in the form of the cyclic dimer of caprolactam and/or nylon-6 derived from colored regenerated post-consumer nylon carpet fibers.

Abstract: Multicomponent fibers and methods and apparatus for producing the same are provided such that an inter-domain boundary layer is interposed between distinct domains formed of incompatible polymers so as to minimize (if not eliminate entirely) separation of the domains at their interfacial boundary. The inter-domain boundary layer is formed of a heterogeneous mixture of the polymers forming the respective adjacent domains between which the boundary layer is interposed. The inter-boundary layer will most preferably include rivulets or fingers of each polymer forming the adjacent domains which interlock with one another in a randomly tortuous manner. These different polymer rivulets thereby effectively increase the surface area and mechanical interlocking at the interfacial boundary between the fiber domains thereby increasing the adhesion therebetween.

Abstract: Novel bicomponent fibers have a sheath domain and an core domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The core domain is annular and defines a longitudinally extending central void. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and a fiber-forming polyolefin polymer constitutes the core. The preferred trilobal bicomponent fibers will exhibit a modification ratio of between 2 to 4, an arm angle of between 7.degree. to about 35.degree., and a total cross-sectional void area between about 3 and about 10 percent. Each lobe of the fiber may optionally contain a lobal void space which, if present, is preferably radially elongate in cross-section.

Abstract: Multicomponent fibers have a primary core, and multiple secondary cores equidistantly radially spaced from one another and from the primary core. The primary and secondary cores are entirely embedded within (and thus completely encased by) a primary sheath. Optionally, the primary sheath may be entirely or partly surrounded by a secondary sheath. The primary and secondary cores may be spun from polymers having distinctly different or complementary properties which are surrounded by a sheath or sheaths formed of another polymer(s) which protects the cores.

Abstract: Novel bicomponent fibers have a polyamide domain and a contaminant-containing polymer domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and the contaminant-containing polymer constitutes the core. Surprisingly, even though the core is formed of a contaminant-containing polymer (which is difficultly spinnable), the bicomponent fibers are readily spinnable and exhibit properties which are comparable in many respects to fibers formed from 100% polyamide. Preferably, the fibers are concentric sheath-core bicomponent fibers having an uncontaminated nylon-6 sheath and a core formed from nylon-6 having a relatively high level of contamination in the form of the cyclic dimer of caprolactam and/or nylon-6 derived from colored regenerated post-consumer nylon carpet fibers.

Abstract: Bicomponent fibers of different cross-sections may be formed without changing the geometry of the spinneret orifices. More specifically, at least two polymers are co-melt-spun through an orifice of fixed geometry so as to achieve a bicomponent fiber having a desired cross-section. In order to change to a bicomponent fiber having a cross-section which is different, therefore, at least one of (1) the differential relative viscosity, (2) the relative proportions of the first and/or second polymers, and (3) the cross-sectional bicomponent distribution of the first and second polymers, is changed. In such a manner, therefore, a wide variety of bicomponent fibers having different cross-sectional geometries may be produced without changing the fixed geometry orifice through which the polymers are co-melt-spun. Thus, bicomponent fiber cross-sections may be "engineered" to suit a variety of needs without necessarily shutting down production equipment in order to change spinnerets.

Abstract: Multicomponent fibers and methods of producing the same are provided such that an inter-domain boundary layer is interposed between distinct domains formed of incompatible polymers so as to minimize (if not eliminate entirely) separation of the domains at their interfacial boundary. The polymer forming the inter-domain boundary layer therefore is provided so as to be compatible with the otherwise incompatible polymers forming each of the domains between which it is interposed.

Abstract: Multicomponent fiber and a method of producing the same whereby the inter-domain boundary layer between the distinct domains is surface roughened and/or mechanically modified so as to increase the surface area contact (and thereby the adhesion) therebetween. As such, delamination of the domains at their interfacial boundary layer is minimized (if not eliminated entirely). Preferably, the fibers are concentric core-sheath bicomponent fibers whereby the core is surface roughened and/or mechanically modified so that of the inter-domain boundary layer between the core and the sheath appears in cross-section to be serrated, undulated and/or ribbed so as to provide a core domain with a shape factor of between about 25 to about 55.

Abstract: Novel bicomponent fibers have a sheath domain and an core domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The core domain is annular and defines a longitudinally extending central void. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and a fiber-forming polyolefin polymer constitutes the core. The preferred trilobal bicomponent fibers will exhibit a modification ratio of between 2 to 4, an arm angle of between 7.degree. to about 35.degree., and a total cross-sectional void area between about 3 and about 10 percent. Each lobe of the fiber may optionally contain a lobal void space which, if present, is preferably radially elongate in cross-section.

Abstract: Colored bicomponent filaments have a particulate colorant dispersed throughout one of the fiber domains while another of the fiber domains is colorant-free. More specifically, the filaments have at least two distinct components arranged longitudinally coextensive with one another. The arrangement of the components may be a sheath/core structure or a side-by-side structure. One of the components contains a colorant and the other one does not (i.e., is colorant free). The colorant-free component is most preferably formed of a polymeric material which is incompatible with the particulate colorant, whereas the colorant-containing component is most preferably formed of a polymeric material which is compatible with the particulate colorant.

Abstract: Novel bicomponent fibers have a polyamide domain and a contaminant-containing polymer domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and the contaminant-containing polymer constitutes the core. Surprisingly, even though the core is formed of a contaminant-containing polymer (which is difficultly spinnable), the bicomponent fibers are readily spinnable and exhibit properties which are comparable in many respects to fibers formed from 100% polyamide. Preferably, the fibers are concentric sheath-core bicomponent fibers having an uncontaminated nylon-6 sheath and a core formed from nylon-6 having a relatively high level of contamination in the form of the cyclic dimer of caprolactam and/or nylon-6 derived from colored regenerated post-consumer nylon carpet fibers.

Abstract: Multicomponent fibers and methods and apparatus for producing the same are provided such that an inter-domain boundary layer is interposed between distinct domains formed of incompatible polymers so as to minimize (if not eliminate entirely) separation of the domains at their interfacial boundary. The inter-domain boundary layer is formed of a heterogeneous mixture of the polymers forming the respective adjacent domains between which the boundary layer is interposed. The inter-boundary layer will most preferably include rivulets or fingers of each polymer forming the adjacent domains which interlock with one another in a randomly tortuous manner. These different polymer rivulets thereby effectively increase the surface area and mechanical interlocking at the interfacial boundary between the fiber domains thereby increasing the adhesion therebetween.

Abstract: Multicomponent fibers have a primary core, and multiple secondary cores equidistantly radially spaced from one another and from the primary core. The primary and secondary cores are entirely embedded within (and thus completely encased by) a primary sheath. Optionally, the primary sheath may be entirely or partly surrounded by a secondary sheath. The primary and secondary cores may be spun from polymers having distinctly different or complementary properties which are surrounded by a sheath or sheaths formed of another polymer(s) which protects the cores.

Abstract: Novel bicomponent fibers have a polyamide domain and an amorphous non-fiber-forming polymer domain which is embedded entirely within, and thereby completely surrounded by, the polyamide domain. The preferred bicomponent fibers have a sheath-core structure wherein the polyamide domain constitutes the sheath and the amorphous non-fiber-forming polymer constitutes the core. Surprisingly, even though the core is formed of a non-fiber-forming polymer, the bicomponent fibers exhibit properties which are comparable in many respects to fibers formed from 100% polyamide. Preferably, the fibers are concentric sheath-core bicomponent fibers having a nylon sheath and a core formed from polystyrene, polyisobutene and poly(methyl methacrylate). Polystyrene, and particularly atactic polystyrene, is preferred as the amorphous polymer domain.