Fibers containing protein and polymer components, methods of use, methods of manufacture, and their related threads, yarns, textiles, and fabrics

Abstract

In one embodiment, a yarn comprising a plurality of fibers is provided. Each fiber may comprise at least 0.5 weight percent of protein and synthetic polymer. Each of the plurality of fibers may be a melt-spun fiber. For each fiber, the outer portion may have a higher protein particle density than the inner portion. Each fiber may be a skin-core fiber comprising an inner core and an outer sheath. The outer sheath of each fiber may comprise at least 1 weight percent of protein. The inner core of each fiber may comprise less than 1 weight percent and / or less than 0.1 weight percent of protein. In another embodiment, a fabric woven from the yarn is provided. The fabric may have no identifiable silk threads or may have no threads to a negligible degree. In another embodiment, a method of manufacturing is provided.

Description

Technology Field

[0001] This application claims priority to U.S. provisional application serial number 63 / 619,265 filed on January 9, 2024, the full text of which is incorporated herein by reference.

[0002] Technology field

[0003] The present application relates to compositions of materials prepared from proteins and containing high or low molar mass additives to aid processability, more specifically, to protein or additive-modified protein materials suitable for melt-spinning into fibers. Additionally, the present application relates to methods for preparing structural protein-synthetic polymer materials, the use thereof, and products formed therefrom (including, but not limited to, textiles). Background Technology

[0004] Proteins are biodegradable molecules derived from living organisms that have evolved to perform specific biological functions. Certain proteins in their natural forms, such as keratin (from, for example, wool and other animal hair) and silk (from, for example, the cocoons of various arthropods such as silkworms), have been used for a long time as attractive materials in textiles and other products due to their excellent balance of utility and aesthetic properties, such as mechanical strength, low thermal conductivity, and an attractive appearance.

[0005] Polyesters and other synthetic polymers are relatively inexpensive and easy to manufacture, and are commonly used in textiles, bottles, and other manufactured products. These synthetic polymers may be characterized by simple, repeating chemical structures; they can also vary in molecular length with little or no change in their observable features. Unlike proteins, which are biological polymers endowed with function as a result of their complex biochemical folding (assuming they are undenatured), synthetic polymers typically fold into substantially random structures and interpenetrate. Likewise, as a result of these chemical structures, it has been proven difficult or impossible to produce textiles from synthetic polymer fibers that substantially mimic the beneficial features of protein-fiber-based textiles—especially in an economical manner.

[0006] Naturally occurring protein fibers can be harvested from biological sources and processed to obtain silk threads, wool yarns, etc., for assembly into textiles through weaving or knitting; however, obtaining these protein-based fibers is relatively expensive and labor-intensive compared to manufacturing synthetic polymer fibers through modern industrial technology and / or harvesting plant-based (typically carbohydrate) fibers (e.g., cotton and bamboo). In other words, procuring cashmere, other wools, raw silk, etc., requires significant agricultural activity even before the manufacturing process can begin. In fact, throughout human history and up to the present, all protein-based fibers (silk, cashmere, wool, etc.) used in textiles have been biologically generated. At the same time, waste proteins are readily available at low cost: for example, the poultry industry produces vast quantities of chicken feathers as waste—which substantially contain keratin.

[0007] Cost-effective use of these waste proteins is limited by the difficulty of reprocessing the proteins into new useful items; such attempts generally involve expensive solution procedures that tend to cause these proteins to lose their attractive properties. Structural proteins such as keratin and silk are generally understood to be semicrystalline and denature and / or decompose at temperatures lower than their melting point, which can allow these protein wastes to be processed at low cost (e.g., melt processing) into new useful textile products that were previously unattainable.

[0008] Scientists have attempted to combine proteins and plastics to arrive at new and useful materials. For example, referring to U.S. Patents No. 9,706,789 and No. 10,595,546, inventor Walter Schmidt pioneered a process of plasticizing waste proteins (e.g., keratin and silk) using various nitrogen-containing compounds to obtain melt-stable protein compositions used in solid industrial products such as animal feed and pollen. However, specifically, these processes and patents did not consider the production of fibers or other materials suitable for textile manufacturing. As another example, referring to U.S. Patent No. 5,705,030, Schmidt and other scientists devised a method to produce fibers and fiber pulp from waste chicken feathers. However, the claimed resulting compositions did not significantly incorporate synthetic polymers or could not be easily processed through existing synthetic polymer processing equipment to produce yarn or textiles.

[0009] Therefore, there is a market demand for methods to economically manufacture fibers, yarns, and textiles that possess (or are close to) the characteristics of natural-derived cashmere, other wools, silk, etc., as well as the resulting textiles and other products. It would be advantageous if such technology could substantially utilize the wide range of existing manufacturing equipment currently used for melt processing synthetic polymers into fibers, yarns, and textiles. It would be even more advantageous if such technology could utilize waste protein materials, such as chicken feathers, which can be obtained at minimal cost and / or are beneficial to the environment through the utilization of industrial waste. Furthermore, it would be advantageous if these resulting fibers and textiles were made of or substantially composed of renewable, sustainable, and / or biodegradable materials; this could help beneficially reduce the impact of fiber processing on energy resources and CO2 generation.

[0010] summation

[0011] The technology disclosed herein advantageously provides a method for manufacturing fibers—and corresponding yarns and textiles—that have both synthetic fiber processability and cost-performance and high-quality fiber aesthetics (e.g., cashmere, merino, silk).

[0012] The present disclosure provides descriptions of exemplary protein-high or low molar mass compositions for solving the perceived problems described above, as well as methods of preparation, methods of use, and related products and ingredients. It should be understood that the description herein is merely exemplary and illustrative and does not limit the concept of the disclosed invention.

[0013] In exemplary embodiments, the disclosed technology enables the production of a new product family in which proteins, particularly structural proteins, retain essential bio-derived properties of the proteins using well-known low-cost melt processing technologies (e.g., fiber spinning, film extrusion, injection molding). As discussed herein, this technology allows structural proteins to be reliably melt-processed at low cost into new products, e.g., textile fibers, which can retain all or substantially the aesthetic properties of the starting proteins, by using additives. In certain embodiments, biodegradability may be preserved by substantially using only additives that are biodegradable in themselves, such as but not limited to low molar amino acids, low molar aliphatic hydroxy acids, high molar aliphatic polyesters, high molar oligopeptides, etc.

[0014] In one exemplary embodiment, a yarn comprising a plurality of fibers is provided. Each fiber may comprise at least 0.5 weight percent of protein and synthetic polymer.

[0015] Each of the multiple fibers may be a melt-spun fiber.

[0016] For each of the multiple fibers, the outer portion may have a higher protein particle density than the inner portion.

[0017] Each fiber may be a skin-core fiber comprising an inner core and an outer sheath. The outer sheath of each fiber may contain at least 1 weight percent of protein. The inner core of each fiber may contain less than 1 weight percent and / or less than 0.1 weight percent of protein.

[0018] Each outer sheath can account for at least 35% by weight of its respective skin-core fiber.

[0019] The protein may be keratin or silk. The synthetic polymer may have a melting point of less than 250°C.

[0020] Each of the plurality of fibers may have a diameter of 8 to 20 micrometers. The outer surface of each outer sheath includes a plurality of circumferential surface cracks. The plurality of circumferential surface cracks may be spaced apart by 0.5 to 2 micrometers.

[0021] Yarn can be filament yarn.

[0022] The yarn may be a staple yarn. Each fiber may have a diameter of 8 to 20 micrometers. Each fiber may have a length of 20 to 128 mm. The outer surface of each outer sheath may include a plurality of circumferential surface cracks. The plurality of circumferential surface cracks may be spaced apart by 0.5 to 2 micrometers.

[0023] Each of the multiple fibers may be crimped. Each fiber may have 5 to 20 crimps per inch and / or 9 to 15 crimps per inch.

[0024] In another embodiment, a fabric woven from a yarn comprising a plurality of fibers is provided. Each fiber may contain at least 0.5 weight percent of protein and synthetic polymer. The fabric may have no or negligible scroop identifiable by the human ear, similar to a fabric made from cashmere and different from a typical synthetic polymer fabric.

[0025] In various other embodiments, methods for manufacturing fibers, yarns, and textiles are provided. Brief explanation of the drawing

[0026] The accompanying drawings included in and constituting part of this specification illustrate some embodiments and aspects of the apparatus and method described herein and are used to explain the principles of the invention together with the description. FIG. 1 is a high-level flowchart illustrating a method for manufacturing textiles from proteins and synthetic polymers according to exemplary embodiments. Figure 2 is an example of a measure of aesthetic properties in fibers and textiles, namely thermal effusivity. FIG. 3 is an example of a melt-spinning technique for producing a filament yarn according to an exemplary embodiment. FIG. 4 is a photograph of a melt-spun protein-synthetic polymer filament yarn wound on a bobbin after melt-spinning, according to an exemplary embodiment. FIGS. 5a, 5b, and 5c are scanning electron microscope (SEM) images of melt-spun protein-synthetic polymer staple yarn fibers at magnifications of 250X, 500X, and 2500X, respectively, according to exemplary embodiments. FIGS. 6a, 6b, and 6c are scanning electron microscope (SEM) images of melt-spun protein-synthesized polymer filament yarn fibers at magnifications of 200X, 500X, and 2500X, respectively, according to exemplary embodiments. FIGS. 7a and 7b are confocal Raman microscopy images of a melt-spun protein-synthetic polymer filament and a staple fiber, respectively, according to an exemplary embodiment. FIGS. 8a, 8b, and 8c are energy-dispersive X-ray spectroscopy (EDX) images showing the nitrogen (N) signature of a melt-spun protein-synthetic polymer filament yarn fiber, a melt-spun protein-synthetic polymer staple yarn fiber, and a keratin protein, respectively, according to exemplary embodiments. FIGS. 8d, 8e, and 8f are energy-dispersive X-ray spectroscopy (EDX) images showing the sulfur (S) signature of a melt-spun protein-synthetic polymer filament yarn fiber, a melt-spun protein-synthetic polymer staple yarn fiber, and a keratin protein, respectively, according to exemplary embodiments. FIGS. 9a, 9b, and 9c are Fourier transform infrared spectroscopy (FTIR) results for compounded batches of keratin, PLA, and keratin-PLA, respectively, according to exemplary embodiments. Specific details for implementing the invention

[0027] details

[0028] Referring to FIG. 1, an exemplary method (100) for manufacturing a textile using a protein and a synthetic polymer is disclosed. In an exemplary embodiment, the method (100) may relate to the production and use of a melt-spun protein-synthetic polymer filament yarn and / or staple yarn.

[0029] As in step (110), a suitable protein can be obtained, preferably from agricultural waste and / or through the recycling of discarded protein-based textiles, other materials, and / or their components.

[0030] In exemplary embodiments, the protein used may include, be composed of, or substantially composed of keratin, but the present disclosure is not so limited. Keratin is a protein that defines the chemical properties of attractive naturally occurring fibers such as wool, cashmere, merino wool, alpaca, angora, camel, mohair, etc. It is also a protein of other animal hair, human hair, feathers, nails, hooves, etc. The inventors have confirmed that the use of keratin in the method (100) can result in economical fiber / textile production and a produced textile having excellent aesthetic quality that is close to that of a textile made of naturally occurring keratin fibers.

[0031] Poultry feathers, for example, feathers from birds raised for food, are generally considered waste and are typically crushed to provide ingredients for animal feed or buried in landfills. Billions of pounds of poultry feathers, more specifically chicken feathers, are discarded annually and considered as a desirable and suitable source of protein. However, the present disclosure is not so limited: feathers from ducks, turkeys, and other birds may be used. In various embodiments, feathers from the head, wings, and / or feet of birds may be used or omitted. Keratin sources may include intact feathers, broken feathers, and / or feather fluff. However, based on current experiments and research by the inventors, the use of feather shafts and quills appears unlikely to produce fibers having characteristics significantly different from the use of fluff alone.

[0032] In addition, it is considered that poultry feathers can be selected wholly or partially based on the feather color that can be finally (at least partially) imparted to the resulting protein-synthetic polymer composition, its fibers, and yarns and textiles containing them.

[0033] In an alternative embodiment, it is considered that other keratin-containing animal products and by-products may be used as protein sources. For example, protein sources may include waste wool; cashmere waste; hair (including, but not limited to, discarded human and pet hair); animal horns, fingernails, and claws; and / or other keratin sources.

[0034] However, the present disclosure is not limited to the use of keratin and keratin-containing materials as protein sources. In alternative embodiments, silk and / or other suitable animal proteins, and / or other structural proteins such as those derived from soybeans may be used.

[0035] After procuring the protein source, the process can proceed to step (130).

[0036] As in step (130), the protein may be synthesized and / or prepared for plasticization. This may include a sub-step of washing and drying the raw protein source, a sub-step of reducing the size of the protein source material, a sub-step of grinding the protein source material to a desired particle size or particle size range, and / or a sub-step of drying the powdered protein.

[0037] For example, preparing keratin from waste poultry feathers may involve washing the feathers and coarsely chopping them for further processing (e.g., assuming that the chopped feathers and / or feather fluff are not provided as a protein source). The washed chopped feathers may then be ground into a powder having, for example, a substantially uniform particle size of <100 micrometers. However, in some embodiments, a particle size of less than 10 micrometers, for example, an average particle size of 5 to 7 micrometers, and / or an aspect ratio of less than 40 may be used. The ground feather powder may then be further dried, for example, to <100 ppm water.

[0038] In another example, waste wool or waste cashmere can be washed, cut, ground, and / or dried to obtain a suitable processed protein powder.

[0039] In step (150), when the protein powder is to be compounded with a polyester carrier, such as PHA, PEF, PLA, PP and / or PET, it may be particularly important or desirable to remove a significant amount of water content. This is because bio-based and similar synthetic polymers are hydrolyzably unstable; and the retention of excessive moisture in the protein powder may impede the production of the resulting fibers and / or at least have a negative effect on their characteristics.

[0040] It may be noted that upon completion of step (130), the resulting protein powder is unlikely to consist entirely of the desired protein, e.g., keratin. That is, it is thought that smaller amounts of other proteins, carbohydrates, other animal byproducts, and / or various other substances remain in the powder. If the prepared protein powder contains a limited amount of these impurities (e.g., less than 5%, less than 1%, less than 0.5%, less than 0.1%, and / or less than 0.01%), it is unlikely to substantially impair the remaining steps of the method (100) or the characteristics of the resulting fiber or textile.

[0041] The process can proceed in steps (150).

[0042] As in step (150), the protein can be plasticized and melt-stable through combination with a carrier molecule. In an exemplary embodiment, this step can be performed via melt extrusion, for example, in a conventional industrial-scale melt extruder. As part of or prior to step (150), a suitable carrier (and / or additive) can be selected and a desired protein-to-carrier ratio can be determined.

[0043] Important features in the selection of a polymer carrier may include (1) a polymer melting temperature lower than the degradation temperature of the selected protein (e.g., 250°C for keratin), and (2) compounding compatibility between the protein and the carrier. Regarding (2), it can be noted that compatibility is not expected to require integration at the molecular level, but rather that the carrier polymer can be properly bound to and connected to the protein molecule.

[0044] Suitable additives may include nitrogen-containing molecules and / or hydroxyl-containing molecules. In certain exemplary embodiments, the carrier-additive may include low molar mass molecules—e.g., amino acids, aliphatic hydroxy acids, etc.—and / or high molar mass molecules—e.g., oligopeptides of aliphatic polyesters, etc.

[0045] In certain exemplary embodiments, PLA, other polylactides, polyhydroxyalkanoates, other polyesters, and / or other synthetic polymers having a melting temperature of less than 250°C may be used as carriers. In this way, keratin (or other proteins) may be closely mixed with biopolymers such as PHA, PEF, PLA and / or PET, and / or other high molar mass carriers during the compounding process. Consequently, hot melt processing at lower temperatures can substantially prevent or at least reduce the occurrence of degradation of keratin or other processed proteins. For reference, the present art suggests that biopolymers such as PHA, PEF, and / or PLA can improve the thermal stability of keratin and / or other proteins, thereby enabling compounding and hot melt spinning at higher temperatures.

[0046] In certain exemplary embodiments, the carrier may comprise polylactide. Advantageously, polylactide is a biodegradable synthetic polyester that can be obtained entirely from renewable resources. In other exemplary embodiments, the carrier polymer may comprise PET, polyolefin, biopolyolefin, biopolypropylene, maleated biopolypropylene, bionylon, etc. In some embodiments, to achieve desirable mechanical properties and thermal stability in the resulting fiber, the selected carrier may need to be completely or at least partially crystallized. However, it may be noted that PET may have an undesirably high melting point.

[0047] A wide range is considered for the ratio of the prepared powdered protein (including, as discussed above, a limited inclusion of other protein and byproduct components) to the synthetic polymer carrier or low molar mass modifier. For example, the keratin concentration in the preferred fiber composition may vary from about 1 wt% to over 90 wt%, or in alternative embodiments, may be as low as 0.5 wt%. The inventors have confirmed that adding only a low concentration of keratin to the polymer additive creates new and desirable textile products while maintaining the flexibility of synthetic polymer melt spinning and fiber manipulation techniques, while imparting aesthetic characteristics associated with biologically produced keratin fibers. However, it is considered that different protein-carrier ratios may impart distinct characteristics to the produced fibers and textiles. For example, the inventors' studies and experiments suggest that a higher percentage of keratin content may impart silk-like aesthetic textile characteristics.

[0048] Once a polymer carrier is selected and appropriate amounts of protein powder and carrier are provided, they can be compounded together. In certain preferred embodiments, compounding may be improved by first grinding the protein powder to a uniform and small particle size. In some embodiments, an average particle size equal to or smaller than the diameter of the starting keratinous material may be preferred. For example, such an average particle size may be less than about 10 micrometers, 5 to 8 micrometers (e.g., 6 or 7 micrometers or nearby), and / or less than 5 micrometers in various embodiments.

[0049] In certain exemplary embodiments, the composition components may be compounded through a twin-screw extruder. Prior to such extrusion—particularly when containing PLA and / or PHA—it may be desirable to dry or re-dry the carrier polymer to <100 PPM water to maximize stability during processing. The extrusion screw is considered to be designed for medium to strong mixing and high shear. The inventors have confirmed that if the dispersion and shear are too weak, the protein and carrier will be insufficiently bound, whereas if the shear is too strong, it may alter the molecular weight of the polymer carrier and / or cause degradation of the protein components. During the extrusion process, the processing time and temperature must be controlled to minimize or eliminate protein degradation and / or denaturation.

[0050] In an exemplary embodiment, a twin-screw extruder may preferably provide the protein-polymer composition in the form of a rod. The extruded protein-polymer composition may preferably be pelletized for storage, transport, and / or sale—and for further processing according to typical polymer / polymer fiber manufacturing techniques. In some embodiments, the rod and / or pellet may be cooled via a water bath or similarly. If this sub-step is used, it may be desirable to re-dry the pellet (or rod) to minimize potential hydrolytic instability.

[0051] As would be understood by a person skilled in the art, the extruded protein-synthetic polymer composition may have a higher concentration of protein and / or additives than can be finally used for fiber formation (e.g., step (170) below).

[0052] The process may proceed to step (170). However, in certain embodiments, it is considered that the polymer composition may be transported and / or sold so that step (170) may occur at a different location (e.g., a melt-spinning facility) and / or be performed by a different entity.

[0053] As in step (170), the extruded polymer can be formed into fibers through melt spinning. Advantageously, fibers can be manufactured on a large scale using conventional melt-spinning technology. Referring to FIG. 3, a conventional melt-spinning process in a continuous process machine is illustrated.

[0054] In an exemplary embodiment, melt-spinning may be carried out in commercially available equipment compatible with the carrier-polymer used and at a temperature suitable for melt-spinning the carrier-polymer, but preferably at the lower end of this range. As with step (150), during the melt-spinning process (170), the time and temperature of the process must be controlled to minimize or eliminate protein degradation and / or denaturation. Preferably, melt-spinning may be characterized by uniform quenching.

[0055] The total fiber elongation and the draw ratio in the solid state during spinning can be set to obtain a desired fiber diameter. It is expected that specific fiber characteristics can be manipulated by the total fiber draw ratio. For example, thicker fibers can improve strength or durability, while thinner fibers may correspond to a softer feel. Conventional synthetic polymer fiber diameters and known animal fiber diameters used as starting points (e.g., https: / / en.wikipedia.org / wiki / Animal_fiberVarious desired fiber diameters and their associated characteristics can be determined experimentally by reference. The inventors believe that, in exemplary embodiments, the diameter and / or length of the melt-spun polymer fibers may be selected to approximate the diameter and / or length of the natural fibers for which textile characteristics are required. For example, if silk-like characteristics are required, the diameter and / or length of the melt-spun polymer fibers should match or approximate that of silk, about 10 micrometers; such fibers may also be stretched using a multilobed or triangular (e.g., equilateral) spinneret. For example, triangular fibers may correspond to increased luster in the resulting fabric. In various embodiments, the fibers may be stretched to have a diameter of 8 to 20 micrometers, or more narrowly, 12 to 18 micrometers, or 11 to 13 micrometers.

[0056] In certain embodiments, skin-core melt spinning technology may be used to produce filaments having a higher keratin concentration in the skin to maximize beneficial characteristics. For example, in some embodiments, substantially all protein within the fiber may be present in the filament sheath—and the filament core may have no or substantially no protein. For example, in various embodiments, the core may contain less than 1 wt%, less than 0.1 wt%, less than 0.01 wt%, a negligible amount of several weeks, and / or an immeasurable amount of protein. In various embodiments, the sheath may contain more than 0.5 wt%, more than 1 wt%, more than 2 wt%, more than 5 wt%, or more than 10 wt% of protein. The sheath may contain less than 20 wt%, less than 40 wt%, less than 50 wt%, less than 75 wt%, and / or less than 90 wt% of protein. However, certain characteristics are believed to degrade with a sheath protein content of more than 40 wt%. The provision of all, substantially all, or most of the protein within the sheath is considered to have the potential to maximize improved aesthetic fiber properties while minimizing a potential reduction in fiber strength. In certain skin-core fiber embodiments, an additive may be provided to form the sheath to improve the stainability of the fiber and / or the protein particles within it. In various preferred skin-core fiber embodiments, the sheath may account for at least 35%, 40%, 45%, or 50% of the resulting fiber.

[0057] The process may proceed to step (175). However, in certain embodiments, it is considered that the spun filament may be transported and / or sold so that subsequent steps may occur at different locations (e.g., textile factories) and / or are performed by different entities.

[0058] As in step (175), the filament can be processed. For example, referring to the melt-spun fiber example 1 below, this step may be omitted in certain embodiments.

[0059] For example, referring to melt-spun fiber Examples #2 and #3 (discussed below), the spun fibers may undergo controlled surface crazing. As would be understood by a person skilled in the art, even in the non-surface crazing examples, the fibers may be stretched in their solid state by a specified draw ratio, e.g., 2.5 to 3.5. Controlled surface crazing may use a draw ratio approximately 20% to 30%, or about 25%, higher than that typically used for similar fibers. For example, each solid-state fiber may be stretched longer through higher draw ratios, e.g., 3.8 to 4, 4 to 4.2, or 4.2 to 4.4, to create microcracks on its outermost surface. These microcracks essentially create micropores, increasing the surface area of ​​these fibers, which can expose additional protein particles and improve aesthetic properties. Referring to FIG. 6c, the microcracks on the outer surface of the fiber may generally be circumferential and spaced 0.5 to 2 micrometers apart, for example, about 1 micrometer.

[0060] The inventors believe that such surface cracking morphology can make fibers (and corresponding yarns and textiles) appear brighter due to light scattering, improve the aesthetic feel and drapeability of the corresponding textiles, and enhance the dyeing process of the resulting yarns and fabrics. A person skilled in the art will find that these benefits of surface cracking morphology are unexpected, as surface cracking is generally understood to be undesirable for textiles in the case of PHA, PLA, and other synthetic polymer fibers, for example, because it can reduce tensile strength. Based on experimental data, the fiber embodiments disclosed herein are expected to have a tensile strength of 3.5-5 g / denier, or more narrowly 3.75-4.5 g / denier—which substantially exceeds the tensile strength of wool and is similar to the tensile strength of uncracked PLA fibers.

[0061] In a staple yarn embodiment, for example, referring to melt-spun fiber Example #4 (discussed below), the melt-spun fiber may be crimped and heat-treated before being cut and used to form a yarn (e.g., step (180) below). It is thought that the cut length and crimp cycle may be selected to mimic the characteristics of the high-grade or other animal hair fibers to be emulated. Known crimping techniques, including heat crimping techniques, may be used on staple fibers (and / or filament fibers), for example, including heat-treating the crimped fibers at a temperature exceeding the expected salt bath temperature. In various embodiments, the fibers may receive "soft" or "strong" crimping at varying depths and may be crimped to 5 to 20 crimps per inch (CPI), and / or more narrowly to 9 to 15 CPI. In certain preferred embodiments, "soft" crimps can achieve excellent aesthetic qualities, including the perceived softness of the resulting fabric: for example, 6-8 CPI can mimic certain aesthetic characteristics of cashmere and 9-11 CPI can mimic certain aesthetic characteristics of merino wool. In various embodiments, the cut length may be 20 to 128 mm or more narrowly 35 to 60 mm.

[0062] Additionally or alternatively, false twist texturing may be used to add volume. These and other embodiments may utilize cutting the fibers into short lengths, such as natural wool or cashmere; producing staple fibers that can be twisted (spun) into yarn; or texturing the product, filament, or staple to create a volume similar to that of natural fibers.

[0063] In certain alternative embodiments, the fiber may be formed (or spun) to have a non-circular cross-section, e.g., triangular or multilobed, thereby further conforming to the cross-sectional morphology of naturally occurring silk or other fibers.

[0064] The process may proceed to step (180). However, in certain embodiments, it is also considered that the spun (and / or processed) fiber may be transported and / or sold so that subsequent steps may occur at different locations (e.g., textile factories) and / or are performed by different entities. In some embodiments, it is also considered that steps (180 and 185) may be omitted, for example, when textile manufacturing (step (190)) uses monofilament rather than yarn.

[0065] As in step (180), the processed filament and / or unprocessed filament (if step (175) is omitted) may be processed into staples and / or filament yarns using, for example, methods known in the relevant art.

[0066] The process may proceed to step (185). However, in certain embodiments, it is also considered that the yarn may be transported and / or sold so that subsequent steps may occur at different locations (e.g., textile factories) and / or are performed by different entities. In some embodiments, it is also considered that step (185) may be omitted entirely.

[0067] As in step (185), the yarn may be treated by dyeing and / or other methods known in the relevant art. As will be understood by a person skilled in the art, the fibers and yarns disclosed herein are expected to essentially accommodate almost any dye chemical effective for the protein used, since they contain such protein components. This susceptibility to conventional dyeing may also be enhanced through additives or skeletal modifications made possible by fiber morphology control.

[0068] The process can proceed to step (190).

[0069] As in step (190), the fibers may be manufactured into textile products through weaving, knitting, and / or other known processes. Melt-spun polymer fibers are considered to be usable to manufacture textiles in substantially the same way as commonly used fiber yarns (e.g., polyester, wool, silk, cashmere, cotton, etc.). Method (100) may be completed.

[0070] Characterization of polymer fibers and textiles

[0071] While textile aesthetics such as "tactile feel" and "drapeability" can be difficult to quantify through objective measurements, textile experts have developed a series of objective measurements to describe desirable textile characteristics for textile products. For example, referring to Fig. 2, thermal diffusivity, one textile aesthetic characteristic, is defined by ASTM Test Method 07984 and correlates with garment performance. Textiles can also be objectively characterized by measurements from the Kawabata evaluation system. (e.g., https: / / textiles.ncsu.edu / tpacc / comfort-performance / kawabata-evaluation-system / (Reference) These measurements include compressive properties evaluated by the KES-FB3 compression tester; bending properties evaluated by the KES-FB2 bending tester; surface properties such as the coefficient of friction and geometric roughness evaluated by the KES-FB4 surface tester; and shear and tensile properties evaluated by the KES-FB1 tensile-shear tester.

[0072] "Skinning" is another aesthetic characteristic that represents a subtle but undesirable sound typically produced by synthetic fiber fabrics when rubbed together between the thumb and index finger, but not by certain "premium" fiber fabrics such as fine wool. A preferred embodiment of the present disclosure can produce a protein-synthetic polymer fabric that is similar to natural high-quality "premium" fabrics, with no skinning or a negligible level of skinning.

[0073] The novel fibers disclosed herein can also be objectively characterized by filament size, cross-sectional measurements, surface features, fiber diameter, etc. Additionally or alternatively, the novel properties of these fibers can be characterized using critical morphological parameters such as degree of crystallinity, molecular orientation, glass transition or melting temperature, and dimensional stability.

[0074] The specific novel fiber disclosed herein may be characterized as being melt-processed into a fiber of textile denier (1-30); containing up to 95 weight% of protein; containing at least 0.5 weight%, 1 weight%, or 2 weight% of protein; and / or containing at least 0.5 weight%, 1 weight%, or 2 weight% of keratin protein.

[0075] Melt-spun fiber production Example #1: Filament yarn

[0076] The following is an experimental example of producing a keratin-containing filament yarn having excellent aesthetics according to method (100) (steps (175, 185, and 190) are omitted):

[0077] Chicken feathers from downlite were ground at a speed of 5 lb / hr in a Restch centrifugal grinder, model ZM200, with a .25 mm screen.

[0078] The feathers were loosely packed in a pillowcase and dried at 80°C for 8 hours in a column dryer with dry air at a dew point of -40°C. The polylactic acid polymer (Kinpoly HT101) was dried in the same column dryer.

[0079] Polylactic acid was fed into a Leistritz 27mm twin-screw extruder via a precision feeder. Crushed feathers were precision-fed into the PLA melt at 10 wt% via a side feeder. The screws were configured for strong shear and mixing. The feather / PLA melt blend was extruded through a die into a water-cooled bath and pelletized. The pellets were dried in a column dryer with dry air at 65°C and -40°C dew point for 8 hours.

[0080] The pellets were fed from the hopper dryer to the hopper of the Hills melt spinneret at a rate of 7.89 wt% along with similarly dried PLA from the aforementioned source.

[0081] A yarn of 726.8 / 144 denier / filament was wound at 1060 m / min at a spinning temperature of 230°C, a spinneret hole diameter of 0.6 mm, and a maximum roll temperature of 85°C.

[0082] Approximately 0.25 lb was wound onto a bobbin. Referring to FIG. 4, an embodiment of a melt-spun protein-synthetic filament wound onto a bobbin is illustrated. Unexpectedly, the melt-spinning process is believed to cause an increased proportion of the keratin component of the composite to accumulate on the externally exposed portion of the composite fiber rather than internally.

[0083] The yarn was wound from the bobbin onto a display card approximately 4 in length and 2 in width.

[0084] The characteristics of the yarn were a denier per filament of 5.04, a toughness of 1.24 g / denier, and an elongation of 21.3%. The fiber was a uniform light beige color and had a translucent luster that was judged to be closer to natural fibers such as silk than to the characteristic luster of synthetic fibers. The fiber was judged by fiber experts to have a more natural feel than synthetic fibers.

[0085] Melt-spun fiber production Example #2: Filament yarn using controlled crazing

[0086] The following is an experimental example of producing a keratin-containing filament yarn having excellent aesthetics, substantially according to Example 1 of melt-spun fiber production, but with the addition of an embodiment of step (185). Specifically, in this example, a step of deformation-induced crazing of the surface of the filament before yarn formation was added.

[0087] A high draw ratio was applied to the filament of Example 1, which produced melt-spun fibers, so that only the surface, rather than the entire fiber, would undergo stretch breakage; this is referred to herein as controlled crazing. While controlled crazing techniques for PLA fibers may be known in the art, the results of controlled crazing on composite melt-spun protein-polymer fibers were unexpected. Specifically, after controlled crazing, the composite melt-spun polymer fiber / yarn of this example had an aesthetic quality that was almost indistinguishable from silk.

[0088] The resulting yarn had a very fine denier and could be characterized as a slip-glide fiber. The inventors believe that the controlled crazing of the composite changed the surface texture, exposing more keratin elements of the composite and causing a softer touch. The yarn was woven into a textile / fabric. Textile experts could hardly distinguish between the fabric samples woven from the composite melt-spun polymer fibers / yarn and the similarly woven silk samples based on aesthetic appearance and touch.

[0089] Melt-spun fiber production example #3: Skin-core architecture filament yarn using controlled crazing

[0090] In another experimental example, keratin powder and PLA were compounded to obtain a master batch pellet containing about 40 wt% keratin protein.

[0091] Next, skin-core architecture fibers were melt-spun using techniques known in the relevant art field. Protein-free PLA was extruded to form the core, and a sheath was extruded from approximately 5-10% masterbatch pellets and additional PLA pellets. The spun fibers were surface-crazed and then twisted to form filament yarns. Surface crazing was achieved using a solid-state draw ratio of 4.1.

[0092] Each of the generated fibers had a diameter of about 15 micrometers and, based on the tensile strength measurements of Example 4, had an estimated tensile strength of at least 4 g / denier and up to 5 g / denier.

[0093] The resulting yarn had a very fine denier and could be characterized as a slip-glide fiber. The inventors believe that the controlled crazing of the composite changed the surface texture, exposing more keratin elements of the composite and causing a softer touch. The yarn was woven into a textile / fabric. Textile experts could hardly distinguish between the fabric samples woven from the composite melt-spun polymer fibers / yarn and the similarly woven silk samples based on aesthetic appearance and touch.

[0094] The skin-core architecture of the fiber produced by Example 3 could not be observed with conventional imaging, but Fig. 7a shows the skin-core architecture through confocal Raman microscopy. Protein particles on the outer surface of the fiber sheath can also be observed in Fig. 7a.

[0095] Figures 6a, 6b, and 6c are SEM images of the Example 3 filament fiber at magnifications of 200X, 500X, and 2500X, respectively. Referring to Figure 6a, it can be observed that the fiber is uniform and smooth, and its diameter matches the measured denier. Figure 6b shows a cross-section of the filament fiber. Referring to Figure 6c, a surface crack morphology with a spacing of approximately 1 micrometer between the stripes on the outer surface of the sheath can be easily observed.

[0096] Figures 8a and 8d show the EDX nitrogen and sulfur signatures of the fibers of Example 3, respectively. The pointillized nature of the nitrogen and sulfur signatures indicates the presence of keratin on the outer surface because the PLA carrier lacks nitrogen in its composition. Figures 8c and 8f show the EDX nitrogen and sulfur signatures of the keratin powder compounded with PLA to form a masterbatch (not shown) that was ultimately used to spin the sheath. The EDX data further confirmed that almost all of the sulfur and nitrogen present in the powdered protein withstood compounding into the masterbatch and subsequently withstood fiber formation, processing, and yarn formation, including extrusion at temperatures exceeding 200°C. This demonstrates that the powdered protein within the masterbatch withstood the manufacturing processes described above without being blown away by gas, and remained present in the protein-synthetic polymer yarn in a substantially intact state.

[0097] The FTIR-ATR results for the fiber of Example #3 were found to be almost indistinguishable from the results of PLA, as shown in Fig. 9b. That is, the FTIR-ATR analysis of Example #3 failed to prove the presence of keratin, which was an unexpected result in terms of the keratin signature reflected in the compounded protein-synthesized polymer (Fig. 9a), as shown in Fig. 9c.

[0098] Melt-spun fiber production Example 4: Skin-core architecture staple yarn

[0099] In this embodiment, the skin-core architecture fibers were spun in substantially the same manner as the filaments of Example 3, but a draw ratio of 3.2 (about 25% less than that used in Example 3) was applied in the solid state, and thus did not have a surface crack morphology. The fibers were then crimped with about 12 crimps per inch, heat-set at 130°C for about 1 minute, and then cut to form 45 mm fibers. These crimping parameters were selected to emulate wool.

[0100] Each resulting fiber had a diameter of approximately 15 micrometers; a tensile strength of approximately 4 g / denier, approaching that of PLA; an elongation of 32%; and a hot air shrinkage of less than 5% at 115°C. These characteristics are highly desirable for garment applications. The high strength combined with the small fiber diameter ensures that the small-diameter yarn possesses sufficient strength to be knitted and woven into fine fabrics. Tensile properties and shrinkage rates are superior to those of wool and are influenced by the carrier polymer and the process. The combination of excellent tensile and shrinkage properties with a soft, natural fiber feel is unique. Furthermore, the fabric derived from this soft crimped, staple yarn did not possess a substantially identifiable slur (based on the ears of both the general public and expert observers), unlike fine wool and all prior art synthetic polymer fabrics known to the inventors.

[0101] The skin-core architecture of the fiber produced by Example #4 could not be observed with conventional imaging, but FIG. 7b shows the skin-core architecture through confocal Raman microscopy.

[0102] Figures 5a, 5b, and 5c are SEM images of the Example 4 staple fiber at magnifications of 250X, 500X, and 2500X, respectively. As in Figure 5a, it can be observed that the fiber is uniform and crimped, and that its diameter matches the measured denier. Figure 5b shows a cross-section of the fiber. And, in Figure 5c, keratin protein particles of about 3 micrometers on the outer surface of the sheath can be easily observed.

[0103] Figures 8b and 8e show the EDX nitrogen and sulfur signatures of the fibers of Example 4. The pointillistic nature of the nitrogen signature indicates the presence of keratin on the outer surface because the PLA carrier lacks nitrogen in its composition. Figures 8c and 8f show the EDX nitrogen and sulfur signatures of the keratin powder compounded with PLA to form a masterbatch (not shown) that was ultimately used to spin the sheath. The EDX data further confirmed that almost all of the sulfur and nitrogen present in the powdered protein withstood compounding into the masterbatch, and subsequently withstood fiber formation, processing, and staple yarn formation, including extrusion at temperatures exceeding 200°C. This demonstrates that the powdered protein within the masterbatch withstood the manufacturing processes described above without being blown away by gas, and remained present in the protein-synthesized polymer yarn in a substantially intact state.

[0104] The FTIR-ATR results for the fiber of Example 4 were found to be almost indistinguishable from the results of PLA, as shown in Fig. 9b. That is, the FTIR-ATR analysis failed to prove the presence of keratin, which was an unexpected result in terms of the keratin signature reflected in the compounded protein-synthesized polymer (Fig. 9a), as shown in Fig. 9c.

[0105] Additional and / or alternative embodiments and improvements

[0106] The protein-polymer mixture disclosed above is considered to be usable for various other applications outside the textile field. For example, in certain embodiments, the extruded polymer may not be melt-spun into 1D fibers (as in step (170)). Instead, in certain alternative embodiments, the protein-synthetic polymer composition may be extruded into a 2D film for packaging or other applications via conventional film extrusion techniques, such as a high-speed blown film machine. In other alternative embodiments, the protein-synthetic polymer composition may be formed into 3D products, such as bottles, toys, and other consumer goods, via injection molding, stretch blow molding, 3D printing, and / or other known methods of synthetic polymer molding. These products are expected to have unique surface properties.

[0107] Although the aforementioned embodiments have been described in detail through examples and embodiments for clarity of understanding, it will be readily apparent to those skilled in the art, in light of the description herein, that specific changes and modifications may be made without departing from the spirit or scope of the disclosure. Since the scope of the invention is limited only by its claims, it should also be understood that the terms used herein are intended to describe specific aspects only and are not intended to be limiting.

[0108] Note that, as used herein, the singular forms “a,” “an,” and “the” include multiple referents unless the context clearly indicates otherwise. Also note that claims may be drafted to exclude any optional elements. As such, this statement is intended to serve as a prior basis for the use of exclusive terms such as “only,” “only,” or “negative” limitations in relation to the citation of claim elements. As will be apparent to a person skilled in the art when reading this disclosure, each individual aspect described and illustrated herein has individual components and features that can be easily separated from or combined with any of the features of the other aspects without departing from the scope or spirit of this disclosure. Any cited method may be performed in the order of the cited events or in any other logically possible order. Accordingly, the foregoing is merely an illustrative example. It will be understood that a person skilled in the art will be able to devise various arrangements that embody the principles of the present disclosure and are included within the spirit and scope thereof, even though they are not expressly described or illustrated herein.

[0109] Furthermore, all embodiments and conditional language cited herein are intended primarily to assist the reader in understanding the principles of the invention and the concepts to which the inventors have contributed to the development of the technology, and should be interpreted without limitation to such specifically cited embodiments and conditions. Additionally, all statements in this invention citing the principles and aspects of the invention, as well as specific embodiments thereof, are intended to include both their structural and functional equivalents. Furthermore, such equivalents are intended to include currently known equivalents and equivalents to be developed in the future, that is, any developed elements that perform the same function regardless of structure. Accordingly, the scope of the invention is not intended to be limited to the exemplary configurations shown and described herein.

[0110] In this specification, various preferred embodiments have been described with reference to the accompanying drawings. However, it will be apparent that various other modifications and changes may be made and additional embodiments may be implemented without departing from the broader scope of this disclosure. Accordingly, the specification and drawings should be conceived as illustrative rather than restrictive.

Claims

Claim 1 A yarn comprising a plurality of fibers, wherein each fiber comprises a protein and a synthetic polymer, and wherein each of the plurality of fibers comprises at least 0.5 weight% of protein. Claim 2 In paragraph 1, a yarn in which each of the plurality of fibers is a melt-spun fiber. Claim 3 In paragraph 2, a yarn having, for each of the plurality of fibers, an outer portion having a higher protein particle density than an inner portion. Claim 4 In paragraph 2, a yarn in which each of the plurality of fibers is a skin-core fiber comprising an inner core and an outer sheath. Claim 5 In paragraph 4, the outer sheath of each of the plurality of skin-core fibers comprises at least 1 weight% of protein; and the inner core of each of the plurality of skin-core fibers comprises less than 1 weight% of protein on a weight basis. Claim 6 In paragraph 5, a yarn in which each outer sheath accounts for at least 35 weight percent of its respective skin-core fiber. Claim 7 In claim 6, the yarn wherein the inner core of each of the plurality of skin-core fibers contains less than 0.1% by weight of protein on a weight basis. Claim 8 In paragraph 2, the protein is keratin or silk; and the synthetic polymer has a melting point of less than 250°C. Claim 9 In paragraph 4, each of the plurality of fibers has a diameter of 8 to 20 micrometers; and the outer surface of each outer sheath includes a plurality of circumferential surface cracks. Claim 10 In claim 9, a yarn having multiple circumferential surface cracks spaced 0.5 to 2 micrometers apart. Claim 11 In paragraph 5, the yarn is a filament yarn. Claim 12 In claim 1, the yarn is a staple yarn; each of the plurality of fibers has a diameter of 8 to 20 micrometers; and each of the plurality of fibers has a length of 20 to 128 mm. Claim 13 In paragraph 4, the yarn is a staple yarn; each of the plurality of fibers has a length of 20 to 128 mm; and the outer surface of each outer sheath includes a plurality of circumferential surface cracks. Claim 14 In paragraph 13, a yarn having multiple circumferential surface cracks spaced 0.5 to 2 micrometers apart. Claim 15 In paragraph 12, a yarn in which each of the multiple fibers is crimped. Claim 16 In paragraph 15, a yarn in which each of the plurality of fibers has 5 to 20 crimps per inch. Claim 17 In paragraph 15, a yarn in which each of the plurality of fibers has 9 to 15 crimps per inch. Claim 18 In item 15, the outer surface of each outer sheath comprises a plurality of circumferential surface cracks. Claim 19 In paragraph 12, the outer sheath of each of the plurality of skin-core fibers comprises at least 1 weight% of protein; and the inner core of each of the plurality of skin-core fibers comprises less than 1 weight% of unmodified animal protein on a weight basis. Claim 20 A fabric comprising a yarn, wherein the yarn comprises a plurality of fibers, each fiber comprises a protein and a synthetic polymer, wherein each of the plurality of fibers comprises at least 0.5 weight% of protein; each of the plurality of fibers is a melt-spun fiber; and the fabric is a fabric having no scroop identifiable by a human ear or a negligible level.

Images