Patent Application
20230407525
The present invention relates to a melt spun bicomponent filament and method for manufacturing a melt spun bicomponent filament.
To this aim, the invention relates to a melt spun bicomponent filament and a method as defined in the appended independent claims, wherein preferred embodiments are defined in the dependent claims.
In a first independent aspect the invention relates to a method of manufacturing bulked continuous filaments, wherein said method comprises at least the following steps: the step of providing a polymer melt; and the step of melt spinning said polymer melt into a plurality of filaments, wherein the method further comprises inducing a differential stress in the polymer melt and/or the filaments.
In a second independent aspect, the invention relates to a method of manufacturing bulked continuous filaments, comprising the steps of: providing a polymer melt; introducing an exploitable stress into the polymer melt; melt spinning the polymer melt into a plurality of filaments; and exploiting the exploitable stress.
In a third independent aspect, the invention relates to a method of manufacturing bulked continuous filaments, wherein said method comprises at least the following steps: the step of providing a polymer melt; and the step of melt spinning said polymer melt into a plurality of filaments, wherein at least one of the following characteristics is met: inducing a differential stress in said polymer melt; inducing a differential stress in an extruder; or inducing a differential stress in a post-extrusion process.
In a fourth independent aspect, the invention relates to a bulked continuous bicomponent filament comprising: a first polymer composition having at least one property and a second polymer composition having the same property, wherein the at least one property of the first polymer composition is different from the at least one property of the second polymer composition.
The present inventions disclosed and taught herein provides a fiber having greater bulk from filaments due to the novel processes and methods.
In one of many embodiments that will be apparent to those in possession of this disclosure, placing and extruding different polymers, and/or polymers having different configurable characteristics, in the cross section of the spinneret may produce differential flow patterns. These differential flow patterns may be controlled to produce different shear rates from the center of the polymer mass to the outside of the polymer mass creating desirable and predictable crimps and twists of the extruded fibers. Environmentally treating the extruded fibers, such as with, but not limited to, a controlled temperature and/or relative humidity, along with any other treatment processes may set the crimps, twists, and rotations to provide more bulk to the extruded fiber, which may be gathered on godets (rollers) and winders.
In one aspect of the inventions disclosed herein, characteristics of polymer melts may be manipulated to produce desired effects. Throughout this disclosure, it must be understood that the intrinsic viscosities (IV) of the polymer melts may be the same, or they may be different. The desirable characteristics that are obtained through the inventions disclosed are not dependent upon having the IV of each polymer melt be identical or close to the IV of another polymer melt.
In another aspect of the inventions disclosed herein, at least one exploitable stress may be induced into a polymer melt spun filament. This exploitable stress may be exploited while extruding the polymer melt through a spinneret, or by environmentally treating the filament during a post-extrusion process such as during a quench phase or during a gathering operation such as rolling the filaments onto a spool. In some bicomponent core-and-sheath filaments, there exists some stress between the core component and the sheath component. Exploiting this stress has an effect on creating crimps, twists, and rotations if the core is concentric with the sheath. However, if the sheath is not concentric with the core, such as if it is asymmetric, then the stress may be exploited to create and permanently keep more crimps, twists, and rotations thereby providing greater bulk to the filaments. These asymmetric stresses may be purposefully configured by introducing additives into one or both polymer melts before, or while they are being extruded through a spinneret.
Characteristics of the polymer melts that do produce desirable effects may include, but are not limited to: nucleation agents, coloring additives, flow aids such as IV enhancers, plasticizers, and/or molecular weight boosters. Each of these may be used individually, or in any combination with any or all of the others. Configuring the polymer melts used in this disclosure to have different characteristics have been found to have desired effects of producing BCF with more crimps and twists than would otherwise be produced.
In another aspect of the inventions disclosed and taught herein, the temperatures of the extruded polymer melts may have different flow characteristics despite having the same IV and melt viscosity. This may also place asymmetric stresses within the resulting bicomponent filaments with the desired results of producing more crimps, twists, and rotations.
Using nucleating agents, colorant additives, flow aids, melt flow manipulators, plasticizers, and other additives as are known to those ordinarily skilled in the art, may predictably change the crystal size, volume, and/or polymer orientation to a desired and configurable result. Several of the additives may be used to reduce crystallinity and/or open up the crystalline structure as the polymers crystalize. In some cases, these additives don't have to be pre-compounded in the polymer before the extrusion process.
Specifically, one skilled in the art and in possession of the inventions disclosed and taught herein may configure the additions of these or other additives to produce various types of stresses between the polymer melts as they are extruded from the spinneret. That is to say that one polymer melt may have a resulting characteristic that it may produce larger or smaller crystal sizes than the other polymer melt as the two of them are treated during a quench process. Similarly, the volume and/or the polymer orientations may be manipulated through the additions of these additives to produce additional stresses between the combined polymer melts. In one of many examples, a polymer melt of PET may be treated with a nucleation agent such that it crystalizes at a different temperature. This may be used to increase the rate and/or overall efficacy of the crystallization. Then a nucleating agent, and/or any other additives, may be combined in an extruder with a polymer melt of untreated PET, or PET that has only been treated with a colorant additive. The resulting fiber may exhibit a shear force within the filament that will form more crimps while it is temperature treated in the quench process.
These stresses may be manipulated to produce configurable and desirable results through the extrusion and quench processes. In one way, the configuration of the polymer melts may be exploited. One of many examples of this may be to produce a trilobal filament where the core of the filament may have a melt of PET and be treated with one additive, while the sheath may be of PTT and be treated with a different additive, Therefore, the combination as it is extruded will have a stress at interfaces between the polymers resulting in a desirable amount of crimps, twists, and rotations. These crimps, twists, and rotations may be set during the quench process by treating the trilobal extrusion to a temperature that sets the crimps and twists, or the stresses may be further exacerbated by the temperature to increase the crimps and twists.
The polymer melt rheology differences are a source of exploitable stresses that may be introduced. Melt viscosity is a relationship of the polymer-polymer interactions as stress is applied, whereas IV is a relationship between a solvent and the solute as stress is applied. Both have thermal influences, however the melt viscosity has more impact with temperature. Similarly, the molecular weight distribution, chain interactions, and other polymer characteristics known to those ordinarily skilled in the art can cause differences between the two values that may be exploited as described in this specification. For example, changes in molecular weight of a polymer with high entanglement affects the melt viscosity more than intrinsic viscosity.
Those of ordinary skill in the art and in possession of the disclosures and teaching herein will understand that the inventions disclosed herein are not limited to a core-and-sheath implementation but may also be implemented in a side-by-side embodiment. Continuing the example of a trilobal extrusion, the core and two of the lobes may be of a single polymer melt and the other lobe may be of a different polymer melt wherein either one or both of the polymer melts may have one or more additives added in such a manner that a configurable stress will be resident in the extruded melt spun bicomponent filament. This configurable stress may react the melt spun bicomponent filament immediately upon extrusion or it may be directed during subsequent processes, such as but not limited to, the quench process. With or without any subsequent process, the stress will produce a filament with predictable crimps and twists that, when combined with other filaments will yield a desirable bulk continuous fiber suitable for many applications including, but not limited to, flooring surfaces, such as carpet.
Similarly, continuing the example of a trilobal extrusion, in addition to the other embodiments, copolymers may be used as either or both of the polymer compositions as described throughout this disclosure. Those of ordinary skill in the art will understand that copolymers that may be utilized comprise, but are not limited to, a PET/PTT copolymer extruded with a PTT homopolymer. Those in possession of this disclosure and the inventions taught herein will understand that many other copolymers may be used without departing from the spirit of the inventions disclosed herein.
In another aspect of the inventions taught and disclosed herein, the formation of the filament may be utilized to produce a stress within the filament. In one of many embodiments of this aspect, the capillary depth may be adjusted. Configuring the capillary depth with polymer melts having been treated as disclosed herein may produce a configurable shear differential between the extruded fibers that may be exploited immediately upon extrusion from the spinneret, during quench treatment, or at a later stage in processing the filament.
Similarly, having the two polymers extruded at different pressures, either in combination with additives as described herein, or by themselves may also produce an axial shift or stress that may be exploited to form desirable crimps, twists, and rotations to the extruded filament.
The quench process may be used in itself to provide configurable and predictable crimps and twists, or it may be used in combinations with the other inventions disclosed and taught herein. In one aspect, treating an extruded filament with heat on one side of the cross-section of the filament may cause torsional stress in the filament that may be set during crystallization and/or during further processing.
Similarly, varying the stack height of the filaments leaving the capillary may produce exploitable stresses. This may be used alone, or in conjunction with changing the stack draw and the mechanical draw of the filament.
The inventions disclosed and taught herein may be automated and combined in any way. For example, having a first polymer melt of PET and treated with a nucleating agent may be extruded with a polymer melt of Nylon, polypropylene, or polyethylene (or combinations thereof) and treated with a humidity and temperature to produce fibers that, when combined, produce a BCF with a specific amount of crimps. If sensors are installed to measure the properties of the BCF and find that it may differ from the desired product, a system controller may detect the direction of the inconsistency and take appropriate measures to correct it. In one aspect, this may be to adjust the environmental factors of the temperature and humidity. However, the controller may take additional measures of, for example and without limitation, adding an IV enhancer to the either or both of the polymer melt components.
In one of many embodiments, a method of manufacturing bulked continuous filaments comprises at least the steps of providing a polymer melt, and melt spinning the polymer melt into a plurality of filaments where at least one differential stress is induced into the polymer melt and/or the filaments. The polymer melt may be an extrusion of two or more polymers through a spinneret, or it may be a homopolymer that has at least one portion treated differently than another portion such that at least one differential stress is created that may be exploited.
Taking the example of two different polymers, they may have different IVs before they are combined and extruded through a spinneret. Treating the resulting filament with heat and/or humidity will cause the filament to crimp, twist, and/or form a rotation. The crimps and/or twists along the lengths of a plurality of filaments will provide substantial bulk to the filaments resulting in a desirable continuously bulked filament suitable for many applications including, but not limited to carpets and other soft surfaces.
In another non-limiting example, the two polymers may have different molecular weights. Combining these either before or while extruding them through a spinneret may again induce a stress within the melt and/or the filament. This stress may ordinarily crimp and/or twist the filament upon extrusion, or the stress may be exacerbated by treating the extruded filament with a temperature and/or a humidity. In one example, the extruded filament may be quenched by blowing cooling air across the extruded filament. In one embodiment, the use of a consistent temperature for the quench operation may produce similar crimps, twists, and rotations in a plurality of extruded filaments, which may be desirable to produce a consistent bulk among the filaments. Thermal quenching may be used in a variety of ways to produce inconsistent crimps and twists. In this, energy may be removed from the molten polymer by heat exchange methods known to those ordinarily skilled in the art. One method, without limitation may be achieved by manipulating more or less mass of a cooling agent, such as air, by passing it through or across the extruded filaments. The mass of the cooling agent may be controlled to some extent, in this example, by manipulating the relative humidity of the air at different temperatures, which may provide a greater bulk to the extruded filaments. In one possible embodiment, a cooler portion of the quenching air may produce a higher number of crimps and twists, while a warmer portion of the quenching air may produce fewer crimps and twists.
As will be known to those ordinarily skilled in the art, fluids other than air may be used for a quench operation. Similar to water vapor in air, water or other ingredients may be added to quench fluids to produce a relative humidity or equivalent for other fluids. The water vapor, and/or other ingredients, may play a role in exploiting the stresses between bicomponent polymer melts and filaments. The quench operations of the fluids used may be at a consistent temperature or at varying temperatures across a portion or across multiple portions of the filaments. Similarly, they may be single or multidirectional or even radial to the axis of the filament.
When combined into a continuously bulked filament, these differently crimped and twisted filaments may provide a consistent bulk that has more desired features than a bulked filament treated with a consistent temperature cooling air. Also, in this exemplary embodiment, the quenching air does not need to be blown across the plurality of filaments simultaneously or at a specific distance from the points of extrusion. As will be known to those of ordinary skill in the art, varying the stack height, with varying the stack draw, with varying the mechanical draw, or combinations thereof may allow a quench process to act at various, and perhaps multiple, points before the filament is rolled onto a godet or otherwise accumulated. As those of ordinary skill in the art and in possession of the inventions disclosed herein will be aware, varying the stack height, varying the stack draw, varying the mechanical draw, or combinations thereof may also exploit any stress between differently treated portions of a polymer melt. These variations may be used to exploit longitudinal and other stresses in the molecular components of the bicomponent filaments while the polymer melts are crystalizing, or during a quench operation.
Those of ordinary skill in the art and in possession of the inventions disclosed and taught herein will also appreciate that additives may be used to induce a stress between polymers or between different portions of a homopolymer. Such additives include, but are not limited to: a flow aid, a molecular weight booster, an intrinsic viscosity (IV) enhancer, a melt flow manipulating agent, a colorant, a nucleating agent, and/or any combinations of those.
For example, and without limitation, a nucleating agent may be added to a first portion of a homopolymer but not to a second portion before the portions are pressed through a capillary to be extruded through a spinneret. In an ordinary quench operation at a consistent cooling temperature, the portion that had been treated with a nucleating agent may crystalize at a different rate than the untreated portion. In this example, the different rates of crystallization between the portions is a stress that may be exploited to produce twists, crimps, and rotations within the extruded filament.
It must be understood that the term polymer composition comprises a composition that has at least one polymer in it. The polymer composition may also comprise, without limitation, additives that are herein disclosed and identified. Saying this another way, different polymer compositions disclosed herein may comprise portions of matter that have different physical properties while each portion contains at least one polymer. While several embodiments disclosed herein exemplify different polymer compositions with each polymer composition comprising a different polymer and/or different additives, it must be understood that a second polymer composition may differ from a first polymer composition by only a physical property. Examples of physical properties may include, but are not limited to, being at different temperatures and/or being under different pressures.
Similarly, a nucleating agent may be added to a first polymer, which may have a different molecular weight than a second polymer as they are pressed through a capillary to be melt spun. The nucleating agent may be configured to crystalize the two polymers at different rates thereby offsetting or compounding the crimps and twists that may be formed from the stress induced from the polymers having different molecular weights. It will therefore be apparent to those in possession of this disclosure that the additives described herein may be combined with other physical properties of the polymers (or different portions of a homopolymer) to achieved desired stresses and deliver filaments with configurable qualities.
Those familiar with and ordinarily skilled in the art and in possession of the inventions disclosed and taught herein will be aware that more than two polymers may be used in an embodiment without departing from the spirit of the inventions herein. Using an exemplary, but nonlimiting embodiment of three polymer compositions, a first polymer composition may comprise a first polymer by itself; a second polymer composition may comprise a first polymer and a copolymer; and the third polymer composition may comprise a third polymer with a nucleating agent. The extrusion of each of those polymer compositions through a spinneret will combine them as disclosed herein with stresses that may be exploitable to produce desired twists, crimps, and rotations.
The spinnerets may also be configured to produce the desired and exploitable stresses in the polymer melt or filaments. In one of many possible configurations, the produced filament may be a core and sheath design. Having a nucleating agent in the core that produces a polymer that crystallizes at a different rate than the surrounding sheath will produce a stress that, when quenched, will produce crimps and twists throughout the filament. This may be exacerbated by offsetting the core from the axial center of the sheath. Similarly, for a different geometry such as a trilobal configuration, one lobe may be of the first polymer with a nucleating agent and the other lobes made with a different polymer without a nucleating agent, or with a nucleating agent that exacerbates the crystallization rates between them. This non-symmetrical configuration may be applied to other extrusion geometries such as, but not limited to a box or rectangular cross section, and/or a delta cross section, or any other cross-section geometries that are known to those skilled in the art. For example, one corner of a box cross-section may be non-symmetrically configured to extrude a first polymer with a coloring agent, and the other three corners of the box cross section may be configured to extrude a polymer with a molecular weight booster.
In addition to, or in place of non-symmetrical cross-sections, the capillaries in the extruder may be of sufficiently different depths to provide extrusion at different rates thereby causing a stress between the polymers. That is to say that a capillary at a first depth will require a first pressure to extrude a polymer melt at a known rate. A nearby capillary having a second depth will require a different pressure to extrude the polymer at that rate. Therefore, applying the same pressure to the nearby capillaries having different depths will extrude their respective polymer melts at different rates into a filament. Crystallizing these melts during a quench operation may produce desired crimps and twists. From that, it should be apparent to those of skill in the art and in possession of the inventions disclosed and taught herein that different capillary depths and/or polymer melt extrusion pressures may be utilized to create filament having desirable properties in terms of crimps, twists, and rotations.
Along with non-symmetrical cross-sections, other features of the extruders and spinnerets may be utilized within the scope of the inventions disclosed and taught herein. For example, and without limitation, the spinnerets may be configured to produce a rotational twist in the filaments. This may be used in conjunction with any other stress disclosed herein to produce filaments having desired qualities. For instance, an extruded rotational twist may be used together with any of the other methods or processes disclosed herein to produce an exploitable stress in a bicomponent polymer melt or filament. As an example, the spinneret may be configured to produce a right-handed rotational twist in the filament while a nucleating agent may be introduced into one of the polymer melts in a non-symmetrical cross-section that is designed to also produce a right-handed rotational twist. The combination of these two factors will produce a greater rotation than either done singularly. On the other hand, if the right-handed rotational twist configured in the spinneret produces a twist that is greater than desired, a counter-twist may be configured into the bicomponent polymer melt by adding a nucleating agent to one of the polymers prior to it be extruded. If the nucleating agent is added in portions to the polymer melt, then a filament may be produced that has a predominant right-handed rotation along with sections of counter rotations or twists. That is to say that the nucleating agent need not be homogenously mixed within the polymer melt but may be injected at intervals to produce configurable results. On one way, the nucleating agent may be regularly injected into the polymer melt. In another way, slugs of a nucleating agent may be injected into the polymer melt at irregular times to produce an irregular pattern of crimps, twists, and rotations.
Other rheological properties of the polymer melts and filaments may be used and/or combined with those described heretofore. For example, and without limitation, the orientation and elongation of molecules in one polymer of a bicomponent polymer filament may be manipulated to create desired stress with the other polymer. Similarly, chain interactions, and other polymer characteristics known to those ordinarily skilled in the art can cause differences between the bicomponent melt and/or filament that may be exploited to produce desired results.
Any of these rheological properties, when used in light of the inventions disclosed and taught herein, may be used to create a differential stress in a bicomponent polymer melt and/or filament. As an example, and without limitation, performing a mechanical operation (e.g., stretching or flow straightening) and/or adding a chemical interaction (e.g., adding a flow enhancer) in one polymer may create an exploitable rheological difference when that polymer is combined with another polymer and extruded.
In another embodiment of the inventions disclosed and taught herein, a bicomponent filament may be made comprising a first and a second polymer composition, wherein the radial cross section of said filament is composed of a first zone provided by said first polymer composition and a second zone provided by said second polymer composition, wherein in each of said zones providing a part of the circumference of the cross section the center of gravity of the first zones is different from the center of gravity of the second zone, and wherein the volume ratio of the first polymer to the second polymer is in the range of between 1:1 to 1:20.
In another embodiment of the inventions disclosed and taught herein, a bicomponent filament may be made comprising a first and a second polymer composition wherein a radial cross section of said bicomponent filament is comprised of a first zone provided by said first polymer composition and a second zone provided by said second polymer composition, wherein each of said zones provides at least a portion of the circumference of the cross section wherein the center of gravity of the first zone is different from the center of gravity of the second zone, and wherein the radial cross section comprises three or more lobes.
In another embodiment of the inventions disclosed and taught herein, a spinning installation for spinning a filament may be made comprising sections of: a spinning section for spinning out spun filaments; a quenching section for quenching said spun filaments; a finishing section for applying finish to the quenched filaments; a drawing section for drawing the finished filaments to final denier; a heating section for heating the drawn filaments thereby crimping the drawn filaments above their crimping temperature; and a cooling section for cooling the crimped filaments. Additionally, the spinning installation may comprise a section where the filaments are entangled and create tac points in which yarn is held together thereby preventing the individual filaments from separating out of the yarn bundle.
With the intention of better showing the characteristics of the invention, herein after, as an example without any limitative character, some preferred embodiments are described, with reference to the accompanying drawings, wherein:
In the way of example and without limitation,
Those of ordinary skill in the art will note that to illustrate the inventions taught and disclosed herein, some components, such as pumps and monitoring equipment, have been left out of this illustrative schematic for clarity.
Within the spin station 106, the polymer compositions may be rejoined to form a plurality, or bundle of extruded filaments 114 with at least one differential stress. For example, and without limitation, the resulting filaments 114 may be a trilobal filament with the core comprising the first polymer composition; two of the lobes also comprising the first polymer composition; and the third lobe comprising the second polymer composition that contains the IV enhancer.
Similarly,
Those of ordinary skill in the art will understand that the spin stations illustrated in
Within the spin station 206, the polymer compositions may be rejoined to form a plurality, or bundle of extruded filaments 214 with at least one differential stress. For example, and without limitation, the resulting filaments 214 may be a trilobal filament with the core comprising the first polymer composition; two of the lobes also comprising the first polymer composition; and the third lobe comprising the second polymer composition that contains the optional IV enhancer. In another embodiment, the optional IV enhancer may not be mixed with the second polymer composition, however, the extruded filaments 214 would still have at least one exploitable differential stress.
As noted throughout this specification, rather than an IV enhancer being injected into the second polymer composition, other additive may be mixed, such as but not limited to a flow aid, a molecular weight booster, a melt flow manipulating agent, a colorant, a plasticizer, a nucleating agent, or combinations thereof.
As shown in
As may be known to those of skill in the art and in possession of the teachings and inventions within this disclosure, tacking may induce yet another exploitable stress within filaments. Tacking may be combined with other means for inducing exploitable stresses disclosed herein to contribute to producing desirable crimps, twists, and rotations.
The exemplary tacking device 325 may be air entanglers that use room temperature air for entangling the filaments. In other embodiments, the tacking devices may include heated air entanglers (e.g., air temperature is higher than room temperature) or steam entanglers, for example that may exploit any differential stresses in the filaments 314.
The bundles of tacked filaments 326 may be drawn to a final titer by drawing device 360, which may be a plurality of godets. The godets may each be turned at a different speed, according to some embodiments.
In alternative embodiments (not shown in
And, in yet another embodiment (not shown in
The bundles 314 may be texturized separately through a texturizer 372. Following this step, a bundle 328 of texturized filaments are provided.
The texturizer 372 may apply air, steam, heat, mechanical force, or a combination of one of more of the above to the filaments to cause the filaments to bulk (or crimp/shrink) from their exploitable stresses.
Next, the texturized filaments 328 may be provided to an individual color entanglement process prior to the final tacking at tacking device 380.
The tacking device 329 may be air entanglers that use room temperature air applied at a pressure, for example, for entangling the filaments. But the pressure may be varied with an increased number of filaments, increased denier per filament, and/or increased the speed of filament production. And, in other embodiments, the tacking device 329 may include heated fluid entanglers (e.g., air temperature is higher than room temperature) or steam entanglers, for example. The tacking may be done more frequently for a specific look desired.
After being individually tacked with a tacking device 329, the bundle 330 is guided to a mixing cam 340 along with other bundles 330′ and 330″. The mixing cam 340 positions bundles tacked by the tacking device 329 relative to each other prior to being tacked together into a yarn 391 in a final tacking device 380. The mixing cam 340 may be cylindrical and may have an external surface defining a plurality of grooves for receiving and guiding the texturized and tacked bundles.
The first component 422 may include a first additive, such as a molecular weight enhancer 422a, 422b introduced at a gradient having a higher amount near the lobe 422b than at the center 422a. Similarly, the sheath 424 may have some amount of nucleating agent 424a. While the separate polymer compositions may provide an exploitable differential stress by themselves, these may be exacerbated by the inclusion of the additives. In other embodiments in accordance with the first aspect, the first component 422 may not be fully encapsulated by the second component 424 but may still have differential stresses that may be exploitable to provide desirable crimps, twists, and rotations.
The bicomponent filament 600 shown in
The core/sheath multi-component filament 900 in
As another example, in the multi-component filament 1000 shown in
The bicomponent filament 1100 shown in
The multi-component filament 1200 shown in
In other embodiments in accordance with the first aspect, the filament can have four or more alternating segments of the first and second components and no axial voids or more than one axial voids. For example, the bicomponent filament 1500 in
The multi-component filament 1300 shown in
The multi-component filament 1400 shown in
The bicomponent filament 1600 shown in
In other embodiments according to the first aspect, the filaments illustrated in these figures may include more than two components and/or have any radial cross-sectional shape, including any of the shapes described herein.
The present invention is in no way limited to the herein above-described embodiments, on the contrary many such melt spun bicomponent filament and methods may be realized according to various variants, without leaving the scope of the present invention.
| Number | Date | Country | |
|---|---|---|---|
| 63352139 | Jun 2022 | US |
