A regenerated keratin fiber bundle and its wet spinning method

Abstract

This invention discloses a regenerated keratin fiber tow and its wet spinning method. The wet spinning method includes the following steps: dissolving keratin extracted from keratin waste in an alkaline solution to prepare a keratin spinning solution with a concentration of 15-45 wt.%; degassing the keratin spinning solution and pouring it into a storage tank, then extruding it through a spinneret to a primary coagulation bath, and sequentially undergoing primary coagulation, first draft, second coagulation, second draft, third coagulation, third draft, oxidation, fourth draft, washing and oiling, fifth draft, drying and setting, and winding. The keratin fiber tow obtained by the wet spinning method provided by this invention has excellent performance and a smooth appearance, avoiding the problems of filament bundling and breakage, while significantly increasing production capacity. In addition, the regenerated keratin fiber prepared by this invention has a 100% keratin content, does not require blending with synthetic polymers, and retains the skin-friendly comfort of natural wool to the greatest extent.

Description

Technical Field

[0001] This invention relates to the field of textile materials technology, specifically to a regenerated keratin fiber bundle and its wet spinning method. Background Technology

[0002] Regenerated keratin fiber refers to a type of fiber material that is made by extracting keratin from keratin waste (such as poultry feathers, animal hair and horns from the slaughtering industry, as well as waste materials and waste wool fabrics from the textile industry) using chemical and biochemical methods, and then preparing it through wet spinning process. It has attracted widespread attention and has broad application prospects due to its advantages such as environmental friendliness, abundant resources and biocompatibility.

[0003] Researchers both domestically and internationally have conducted a series of studies in this field. Currently published data on the preparation of keratin fibers from waste wool mainly focus on fundamental research such as the preparation of regenerated keratin fiber monofilaments and the enhancement of their mechanical properties. However, from an industrialization perspective, to improve the production rate of keratin fibers and enable large-scale production, it is necessary to shift the keratin fiber spinning process from monofilament preparation to tow preparation. Chinese invention patent CN1425813 discloses synthetic fibers containing animal protein and their preparation method, providing a method for wet spinning keratin fibers using animal keratin and polyvinyl alcohol (PVA) as raw materials. However, this method has a high PVA content (>46%), and PVA is difficult to biodegrade, resulting in composite fibers that lack high biocompatibility. Currently, publicly available data on the preparation of keratin fiber tows with 100% keratin content remains a blank area. The main factor limiting its development is the severe adhesion and tangling of the tows. These keratin fibers are extruded into a coagulation bath via a porous spinneret. The excessive surface tension between the fibers is the main reason for the adhesion and bonding between the fiber bundles. Furthermore, these fibers, when dried directly without surface treatment immediately after forming, exhibit brittleness and hardening. This adhesion and hardening of the keratin fiber bundles causes problems in subsequent processing steps such as cutting, spinning, weaving, and nonwoven fabrication, as well as application development, significantly hindering their large-scale production and commercial viability. Therefore, how to effectively prevent the formation of adhesion points between keratin fibers or break up existing adhesion points is a direction that those skilled in the art are dedicated to solving. Summary of the Invention

[0004] The first objective of this invention is to provide a wet spinning method for regenerated keratin fiber bundles to solve the problem of bundle adhesion in the existing keratin multifilament preparation process.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A wet spinning method for regenerated keratin fiber bundles, the wet spinning method comprising the following steps:

[0007] Step S1: Dissolve the keratin extracted by dissolving keratin waste in an alkaline solution to prepare a keratin spinning solution with a concentration of 15-45 wt.%. The molecular weight of the extracted keratin is between 45-110 kDa, and the pH value of the alkaline solution is controlled between 9.5-12.

[0008] Step S2, First Coagulation: After degassing the keratin spinning solution obtained in step S1, pour it into a storage tank, and then extrude it through the spinneret to the first coagulation bath to form nascent fibers.

[0009] Step S3, First drawing: The nascent fibers obtained in step S2 are drawn for the first time, with a drawing ratio of 0-1 times;

[0010] Step S4, Secondary Coagulation: The nascent fibers after stretching in step S3 are introduced into a secondary coagulation bath for further solidification and shaping of the keratin fibers in the nascent fibers.

[0011] Step S5, Second Drafting: The nascent fibers that have undergone the secondary coagulation bath treatment are subjected to a second drafting, with a drafting ratio of 1-10 times;

[0012] Step S6, Third Coagulation: The nascent fibers after the second stretching are put into a three-stage coagulation bath for further solidification and shaping of the keratin fibers in the nascent fibers.

[0013] Step S7, Third Drafting: The nascent fibers that have undergone three-stage coagulation bath treatment are drafted for the third time, with a drafting ratio of 1-10 times;

[0014] Step S8, Oxidation: The nascent fibers after the third stretching are placed in an oxidation bath for treatment. The temperature of the oxidation bath is controlled between 20-50°C. The oxidation bath is an aqueous solution containing 2-25 wt.% oxidant. In the oxidation bath, the keratin in the nascent fibers reforms disulfide bonds.

[0015] Step S9, Fourth Drafting: The nascent fibers treated in the oxidation bath are subjected to a fourth drafting, with a drafting ratio of 1-10 times;

[0016] Step S10, washing and oiling: The nascent fibers after the fourth stretching are placed in a water washing bath containing oil agent I for treatment. The temperature of the water washing bath is controlled between 20-45℃, and the time is 0.1-3 min. The amount of oil agent I added in the water washing bath is 0.05-20 wt.%.

[0017] Step S11, Fifth Drafting: The fibers after water washing are subjected to a fifth drafting, with a drafting ratio of 1-10 times;

[0018] Step S12, Drying and Shaping: The fibers after the fifth stretching are dried in a hot tunnel at a temperature of 60-150℃ for 0.5-5 minutes.

[0019] Step S13, winding: The dried fibers are finally wound up using a winding machine.

[0020] The primary, secondary, and tertiary coagulation baths are all alcoholic or inorganic salt solutions containing surfactants and oil agent II. The temperature of the coagulation baths is controlled between 20-50℃, and the pH value is controlled between 1.5-3.2. The concentration of the primary coagulation bath is 18-33 wt.%, the concentration of the secondary coagulation bath is 10-18 wt.%, and the concentration of the tertiary coagulation bath is 7-15 wt.%.

[0021] Here, the coagulation bath is designed as a three-stage gradient coagulation process. In step S2, the primary coagulation bath is an 18-33 wt.% alcohol solution or inorganic salt solution; the high concentration of the coagulation bath enables rapid fiber solidification. In steps S4 and S6, the secondary and tertiary coagulation baths further solidify and shape the fiber. In step S3, the draw ratio can be 0-1 times to ensure that the extrusion swelling zone of the fiber is not damaged, allowing the nascent fiber to obtain a better morphology. In steps S5 and S7, the draw action gradually untangles the entangled keratin molecules, promoting the orientation of the intermediate filaments within the fiber to form a more regular aggregate morphology and achieve fiber denier refinement. Simultaneously, strain induces the transformation of the keratin secondary structure from α-helix to β-sheet, which is beneficial for improving the strength of the keratin fiber bundle. The draw ratio in steps S5 and S7 can be 1 to 10 times. Those skilled in the art can select an appropriate ratio according to actual needs, such as, but not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 times, etc.

[0022] Keratin spinning solution undergoes "double diffusion" formation in the coagulation bath. Under tension along the fiber axial direction, the fibers gradually approach each other. Surface tension easily causes excessive adsorption between fibers, leading to interactions and adhesion. Adding cationic surfactants to the coagulation bath neutralizes the charge on the keratin fiber surface, reducing surface tension and the coefficient of friction, thus preventing the fibers from sticking together.

[0023] In one specific embodiment, the surfactant in the coagulation bath is a cationic surfactant, selected from one or more of dodecyl dimethyl benzyl ammonium chloride, cationic polyacrylamide, hexadecyl trimethyl ammonium chloride, octadecyl phosphate substituted amine, polyvinylpyridine quaternary ammonium salt, and dodecyl pyridine ammonium chloride. The amount of the surfactant added is 0.05-10 wt.%. If the amount of cationic surfactant added in the coagulation bath is less than 0.05 wt.%, it will lead to excessive surface tension between fibers, causing the fiber bundles to adhere to each other. If the amount of cationic surfactant in the coagulation bath is greater than 10 wt.%, the surfactant diffuses into the fiber interior, reducing fiber toughness and preventing high-ratio drawing. Those skilled in the art can select any value within the above range according to actual needs, such as, but not limited to, 1 wt.%, 3 wt.%, 5 wt.%, 7 wt.%, 9 wt.%, etc.

[0024] In one specific implementation, the oil agent II in the coagulation bath is selected from one or more of isononyl isononanoate, glycerol, n-decanoic acid, n-hexanoic acid, and lauric acid, and the amount of oil agent II added is 0.05-10 wt.%. Oil agent II imparts lubricity to keratin fibers and improves fiber toughness. If the amount of oil agent II added in the coagulation bath is less than 0.05 wt.%, it will cause fiber breakage; if the amount of oil agent II added in the coagulation bath is greater than 10 wt.%, the oil agent will coat the fiber surface, the fiber will dry more slowly, which is not conducive to the batch winding of fibers.

[0025] In one specific implementation, in step S2, the spinneret in the spinneret assembly has 10-100 spinneret holes with a hole diameter R of 30-120 μm, which are uniformly distributed in a single or multiple rings, and the lateral spacing S between adjacent holes is 5-25 mm.

[0026] Here, a spinneret with low pore density and small orifice size can reduce the influence of the spinneret's shielding effect, increasing the contact area between the keratin filaments and the coagulation bath. This is beneficial for the coagulation of the inner monofilaments and also significantly improves the uniformity of filament coagulation, thus enhancing the stability of the spinning process. If the number of spinneret orifices is greater than 100 and the interval S between two adjacent orifices is less than 5 mm, due to the pumping effect, the axially flowing fine streams perpendicular to the bath liquid have a strong "shielding effect." That is, the coagulation bath in the center of the spinneret flows slowly, easily forming dead corners, resulting in poor coagulation of the monofilaments in the center. The poorly coagulated fine streams will then clump together in large quantities. If the number of spinneret orifices is less than 10 and the interval S between two adjacent orifices is greater than 5 mm, although the filament bundle separation is better, the spinning yield is low, which is not conducive to industrial production.

[0027] In one specific implementation, the alcohol used in the coagulation bath is selected from one or more of methanol, ethanol, and propanol; the inorganic salt used is selected from one or more of calcium chloride, sodium sulfate, sodium dihydrogen phosphate, zinc sulfate, and calcium sulfate; and the acid used for pH adjustment is selected from one or more of acetic acid, acetic acid, and formic acid.

[0028] In one specific implementation, in step S2, the extrusion rate of the keratin spinning solution is 100-1000 μl / min.

[0029] In one specific implementation, in step S8, the oxidant in the oxidation bath is selected from one or more of manganese dioxide, potassium permanganate, hypochlorous acid, sulfur dioxide, peracetic acid, hydrogen peroxide, and sodium periodate. An aqueous solution containing 2-25 wt.% oxidant is chosen for the oxidation bath to reconstruct the disulfide bond crosslinking network within the fiber, further improving fiber strength. The temperature of the oxidation bath is 20-55°C. When the oxidation temperature is below 20°C or the oxidant content is below 2 wt.%, the oxidation efficiency is low, which is detrimental to the reconstruction of disulfide bonds in the keratin filament bundles; when the oxidation temperature is above 55°C or the oxidant content is above 25 wt.%, the oxidation is intense, leading to protein denaturation.

[0030] In one specific implementation, the oil agent I in step S10 is selected from one or more of glycerol, polyethylene glycol, and triethanolamine.

[0031] Oiling and hot tunnel drying of regenerated keratin fiber tows can fix the final morphology of the fibers. Oiling can prevent the mechanical strength of keratin fibers from decreasing over time. The selected oil agent I is a small molecule plasticizer. The addition of small molecule plasticizers can effectively reduce intermolecular forces, improve chain mobility, enhance the diffusion ability of water molecules, and reduce the brittleness of protein materials. Here, the addition amount of oil agent I is 0.5-20 wt.%. If the addition amount is less than 0.5 wt.%, the toughness of keratin fibers will not be improved; if the addition amount is more than 20 wt.%, the breaking strength of keratin fibers will decrease due to excessive oil agent addition.

[0032] In one specific implementation, the keratin spinning solution in step S1 is prepared by the following method:

[0033] A keratin modifier is added to a solution containing dissolved keratin to break the disulfide bonds in the keratin. The keratin modifier is selected from one or more of sodium bisulfite, sodium sulfite, L-cysteine, and dithiothreitol. The weight of the added keratin modifier is 1-40% of the weight of the keratin.

[0034] In one specific embodiment, the solution containing keratin also contains surfactant I, which is selected from one or more of sodium alkyl sulfate, sodium alkyl sulfonate, and sodium fatty alcohol ether sulfate, and its addition amount accounts for 1-30% of the weight of the keratin.

[0035] The regenerated keratin is derived from mammalian hair; preferably, the regenerated keratin is derived from one or more of waste wool textiles such as goat hair, sheep wool, rabbit hair, pig hair, camel hair, and yak hair.

[0036] The present invention does not limit the source of the keratin fiber spinning solution, and can use existing or improved methods, such as ① dissolving all waste wool and concentrating it to prepare keratin spinning solution (dissolution methods include but are not limited to ionic liquid method and eutectic solvent method); ② partially dissolving wool chemically, and then extracting keratin solids by filtration, salting out, centrifugation, and freeze drying, and then dissolving it to prepare spinning solution (including but not limited to reduction method and metal salt method).

[0037] The second objective of this invention is to provide a regenerated keratin fiber bundle, which is prepared by the above-mentioned wet spinning method, wherein the diameter of a single keratin fiber in the regenerated keratin fiber bundle is 5-18 μm.

[0038] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0039] 1) This invention reduces the surface tension of fibers by adding cationic surfactants to the coagulation bath, thereby preventing the fibers from sticking together. It also maintains the toughness of keratin fibers by adding oil agent II to the coagulation bath, thereby reducing the coefficient of friction and improving lubricity.

[0040] 2) A spinneret with low pore density is used, and the extrusion speed of the metering pump is adjusted according to the number of pores to ensure optimal shear stress is applied to the spinning solution, thereby reducing the "shadowing effect" of the spinneret. The multi-stage coagulation bath and multi-stage drawing steps further weaken the van der Waals attraction and radial force between the spinning streams, preventing them from forming an agglomerated state. The keratin fiber streams are solidified and drawn to form keratin fiber bundles. The keratin fiber bundles prepared by the method of this invention have excellent performance and a smooth appearance, avoiding problems such as filament bundling and breakage, while significantly increasing production capacity. Furthermore, the regenerated keratin fibers prepared by this invention have a 100% keratin content, preserving the skin-friendly comfort of natural wool to the greatest extent. The regenerated keratin fiber bundle preparation process is simple, easy to operate, low in cost, and environmentally friendly, making it suitable for industrial-scale production. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a spinneret used in the wet spinning process of a regenerated keratin fiber bundle according to the present invention.

[0042] Figure 2 This is a flow chart of a wet spinning process for regenerated keratin fiber bundles according to the present invention;

[0043] Figure 3 This is an optical microscope (OM) image depicting the surface morphology of the regenerated keratin fiber bundles prepared in Example 1 of this invention;

[0044] Figure 4 This is a scanning electron microscope (SEM) image depicting the cross-sectional morphology of the regenerated keratin fiber bundles prepared in Comparative Example 1 of this invention. Detailed Implementation

[0045] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0046] Unless otherwise specified, all reagents, materials and instruments used in the following examples and comparative examples are commercially available.

[0047] Example 1

[0048] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0049] (1) Preparation of wool keratin spinning solution

[0050] Wool keratin solid powder was dissolved in a 0.6 mol / L sodium carbonate-sodium bicarbonate buffer solution with a pH of 9.5 to make the keratin solution concentration 30 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 1 h, and then centrifuged at 10,000 rpm for 10 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0051] (2) Preparation of regenerated wool keratin fiber bundles

[0052] For the preparation process, please refer to Figure 2 As shown, the above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1 The spinneret shown has 20 holes, a hole diameter of 100 μm, and a lateral spacing of 10 mm between adjacent holes. It is extruded into a primary coagulation bath. The extrusion rate of the spinning solution is 200 μl / min. The primary coagulation bath is an aqueous solution containing 25 wt.% ethanol, 0.2 wt.% cationic polyacrylamide, and 1 wt.% lauric acid. The pH of the coagulation bath is adjusted to 2 with acetic acid. The coagulation temperature is 25℃ and the coagulation time is 0.5 min.

[0053] After exiting the primary coagulation bath, the fiber bundle undergoes a first draft of 0.2 times its original length, followed by a secondary coagulation bath containing 15 wt.% ethanol aqueous solution at pH 2, coagulation temperature of 25°C, and coagulation time of 0.5 min. After exiting the secondary coagulation bath, the fiber bundle undergoes a second draft of 3 times its original length, followed by a tertiary coagulation bath containing 8 wt.% ethanol aqueous solution at pH 2, coagulation temperature of 25°C, and coagulation time of 0.5 min. This process is repeated multiple times, yielding approximately 8000 meters of fiber. The mass ratio of coagulation bath to fiber in each stage is approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid are added to adjust the pH of the three coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the three-stage coagulation bath, the keratin fiber bundles undergo a third stretching, with a stretch ratio of 5 times. The oxidation bath for the keratin fiber bundles is an aqueous solution containing 12 wt.% sodium periodate, with an oxidation temperature of 35°C and an oxidation time of 0.5 min. After exiting the oxidation bath, the fibers undergo a fourth stretching, with a stretch ratio of 2 times. The fiber bundles then enter an oil bath containing 10 wt.% polyethylene glycol, at a temperature of 25°C for 0.5 min. After exiting the oil bath, the fiber bundles undergo further stretching, with a stretch ratio of 1.3 times. They then enter a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid, a washing temperature of 40°C, and a washing time of 1 min. After exiting the washing bath, the fibers undergo further stretching and then enter a 2 m long hot tunnel, with a stretch ratio of 1.1 times, a drying temperature of 80°C, and a drying time of 2 min. Finally, the fiber bundles are collected onto the spool by a winding machine at a winding speed of 30 m / min.

[0054] See Figure 3 As shown, the surface morphology (OM) characterization analysis of the keratin fiber bundles prepared in this example reveals that the keratin fibers are independent of each other, have small diameters, and smooth surfaces.

[0055] Example 2

[0056] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0057] (1) Preparation of wool keratin spinning solution

[0058] Wool keratin solid powder was dissolved in a 0.3 mol / L sodium carbonate-sodium bicarbonate buffer solution with a pH of 9.5 to make the keratin solution concentration 40 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 2 h, and then centrifuged at 10,000 rpm for 10 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0059] (2) Preparation of regenerated wool keratin fiber bundles

[0060] The above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1 The spinneret, with 30 holes, a hole diameter of 60 μm, and a lateral spacing of 8 mm between adjacent holes, was extruded into the primary coagulation bath. The extrusion rate of the spinning solution was 300 μl / min. The primary coagulation bath was an aqueous solution containing 25 wt.% ethanol, 0.3 wt.% dodecyl dimethyl benzyl ammonium chloride, and 1 wt.% glycerol. The pH of the coagulation bath was adjusted to 2 with acetic acid, the coagulation temperature was 25℃, and the coagulation time was 0.8 min.

[0061] After exiting the primary coagulation bath, the fiber bundles were drawn to a ratio of 0.2 and then introduced into a secondary coagulation bath containing an 18 wt.% ethanol aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 30°C, and the coagulation time was 1 minute. After exiting the secondary coagulation bath, the fiber bundles were drawn to a ratio of 3 and then introduced into a tertiary coagulation bath containing a 10 wt.% ethanol aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 35°C, and the coagulation time was 1.2 minutes. This process was repeated multiple times, producing approximately 8000 meters of fiber. The mass ratio of coagulation bath to fiber in each stage was approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid were added to adjust the pH of the three different coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the three-stage coagulation bath, the keratin fiber bundles are stretched. The oxidation bath for the keratin fiber bundles is an aqueous solution containing 10% v / v H2O2, with an oxidation temperature of 35℃ and an oxidation time of 1 minute. After exiting the oxidation bath, the fibers are stretched to a stretch ratio of 2. The fiber bundles then enter an oil bath containing 10 wt.% glycerol at a temperature of 30℃ for 1 minute. After exiting the oil bath, the fiber bundles are stretched to a stretch ratio of 1.3. They then enter a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid, a washing temperature of 40℃, and a washing time of 1 minute. After exiting the washing bath, the fibers are stretched again and then enter a 2-meter-long hot tunnel with a stretch ratio of 1.1. The drying temperature is 80℃, and the drying time is 1 minute. Finally, the fiber bundles are collected onto the spool by a winding machine at a winding speed of 30 m / min.

[0062] Example 3

[0063] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0064] (1) Preparation of wool keratin spinning solution

[0065] Wool keratin solid powder was dissolved in 0.3 mol / L sodium carbonate-sodium bicarbonate buffer solution with pH 9.5 to make the keratin solution concentration 20 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 1 h, and then centrifuged at 10,000 rpm for 10 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0066] (2) Preparation of regenerated wool keratin fiber bundles

[0067] The above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1 The spinneret, with 50 pores and a diameter of 50 μm, and a lateral spacing of 10 mm between adjacent pores, extrudes the fibers into a primary coagulation bath. The extrusion rate of the spinning solution is 600 μl / min. The primary coagulation bath is an aqueous solution containing 25 wt.% methanol, 0.2 wt.% cationic polyacrylamide, 0.2 wt.% dodecyl dimethyl benzyl ammonium chloride, and 1 wt.% glycerol. The pH of the coagulation bath is adjusted to 2 with acetic acid, the coagulation temperature is 35℃, and the coagulation time is 1.5 min. After exiting the primary coagulation bath, the fiber bundle is drawn to a ratio of 0.1 and then enters a secondary coagulation bath containing 18 wt.% methanol aqueous solution. The pH of the coagulation bath is 2, the coagulation temperature is 35℃, and the coagulation time is 1 min. After exiting the secondary coagulation bath, the fiber bundles were drawn to a ratio of 3, and then placed in a tertiary coagulation bath containing a 10 wt.% methanol aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 35℃, and the coagulation time was 1 minute. This process was repeated multiple times, yielding approximately 8000 meters of fiber. The mass ratio of fiber to coagulation bath in each stage was approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid were added to adjust the pH of the three different coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the tertiary coagulation bath, the keratin fiber bundles were drawn to a ratio of 1.2. The keratin fiber bundles were then oxidized in an aqueous solution containing 10% v / v H₂O₂ at a temperature of 25℃ for 1 minute. After exiting the oxidation bath, the fibers were drawn to a ratio of 2. The fiber bundle is then placed in an oil bath containing 10 wt.% glycerol at 35°C for 1 minute. After exiting the oil bath, the fiber bundle is drawn to a ratio of 1.3. It then enters a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid. The washing temperature is 40°C for 0.8 minutes. After exiting the washing bath, the fibers are drawn again and then placed in a 2-meter-long hot tunnel with a draw ratio of 1.1. The drying temperature is 80°C for 2 minutes. Finally, the fiber bundle is collected onto a spool by a winding machine at a speed of 60 m / min.

[0068] Example 4

[0069] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0070] (1) Preparation of wool keratin spinning solution

[0071] Wool keratin solid powder was dissolved in a 0.4 mol / L sodium carbonate-sodium bicarbonate buffer solution with a pH of 9.5 to make the keratin solution concentration 35 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 2 h, and then centrifuged at 10,000 rpm for 10 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0072] (2) Preparation of regenerated wool keratin fiber bundles

[0073] The above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1The spinneret, with 20 holes and a diameter of 50 μm, and a lateral spacing of 10 mm between adjacent holes, was extruded into a primary coagulation bath. The extrusion rate of the spinning solution was 500 μl / min. The primary coagulation bath was an aqueous solution containing 30 wt.% zinc sulfate, 5 wt.% sodium sulfate, 0.5 wt.% cationic polyacrylamide, and 1 wt.% glycerol. The pH of the coagulation bath was adjusted to 2 with acetic acid, the coagulation temperature was 25℃, and the coagulation time was 2 min. After exiting the primary coagulation bath, the fiber bundle was drawn to a ratio of 0.2 and then entered a secondary coagulation bath containing a 15 wt.% ethanol aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 35℃, and the coagulation time was 2 min. After exiting the secondary coagulation bath, the fiber bundles were drawn to a ratio of 3, and then placed in a tertiary coagulation bath containing a 10 wt.% ethanol aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 35℃, and the coagulation time was 2 minutes. This process was repeated multiple times, yielding approximately 8000 meters of fiber. The mass ratio of each coagulation bath to fiber was approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid were added to adjust the pH of the three different coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the tertiary coagulation bath, the keratin fiber bundles were drawn to a ratio of 1.2. The keratin fiber bundles were then oxidized in an aqueous solution containing 10% v / v H₂O₂ at a temperature of 35℃ for 2 minutes. After exiting the oxidation bath, the fibers were drawn to a ratio of 2. The fiber bundle is then placed in an oil bath containing 10 wt.% glycerol at 35°C for 2 minutes. After exiting the oil bath, the fiber bundle is drawn to a ratio of 1.3. It then enters a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid. The washing temperature is 40°C for 1 minute. After exiting the washing bath, the fibers are drawn again and then placed in a 2-meter-long hot tunnel with a draw ratio of 1.1. The drying temperature is 80°C for 4 minutes. Finally, the fiber bundle is collected onto a spool by a winding machine at a speed of 30 m / min.

[0074] Example 5

[0075] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0076] (1) Preparation of wool keratin spinning solution

[0077] Wool keratin solid powder was dissolved in a 0.3 mol / L sodium carbonate-sodium bicarbonate buffer solution with a pH of 9.5 to make the keratin solution concentration 35 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 2 h, and then centrifuged at 10,000 rpm for 20 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0078] (2) Preparation of regenerated wool keratin fiber bundles

[0079] The above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1 The spinneret, with 50 pores and a diameter of 50 μm, and a lateral spacing of 10 mm between adjacent pores, extrudes the fibers into a primary coagulation bath. The extrusion rate of the spinning solution is 600 μl / min. The primary coagulation bath is an aqueous solution containing 30 wt.% sodium sulfate, 5 wt.% zinc sulfate, 0.5 wt.% hexadecyltrimethylammonium chloride, and 1 wt.% glycerol. The pH of the coagulation bath is adjusted to 2 with acetic acid, the coagulation temperature is 30℃, and the coagulation time is 2 min. After exiting the primary coagulation bath, the fiber bundle is drawn to a ratio of 0.2 and then enters a secondary coagulation bath containing a 15 wt.% sodium sulfate aqueous solution. The pH of the coagulation bath is 2, the coagulation temperature is 30℃, and the coagulation time is 2 min. After exiting the secondary coagulation bath, the fiber bundles were drawn to a ratio of 3, and then entered a tertiary coagulation bath containing a 10 wt.% sodium sulfate aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 30°C, and the coagulation time was 2 minutes. This process was repeated multiple times, yielding approximately 8000 meters of fiber. The mass ratio of each coagulation bath to fiber was approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid were added to adjust the pH of the three different coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the tertiary coagulation bath, the keratin fiber bundles were drawn to a ratio of 1.3. The keratin fiber bundles were then oxidized in an aqueous solution containing 10% v / v H₂O₂ at a temperature of 35°C. After exiting the oxidation bath, the fibers were drawn to a ratio of 2. The fiber bundles were then placed in an oil bath containing 10 wt.% glycerol at a temperature of 30°C for 2.5 minutes. After exiting the oil bath, the fiber bundle is drawn to a ratio of 1.3. It then enters a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid. The washing temperature is 40°C, and the washing time is 2.5 minutes. After exiting the washing bath, the fibers are drawn again and then enter a 2-meter-long hot tunnel with a draw ratio of 1.1. The drying temperature is 80°C, and the drying time is 2.5 minutes. Finally, the fiber bundle is collected onto a spool by a winding machine at a winding speed of 30 m / min.

[0080] Example 6

[0081] This example provides a wet spinning method for preparing regenerated wool keratin fiber bundles, the steps of which are as follows:

[0082] (1) Preparation of wool keratin spinning solution

[0083] Wool keratin solid powder was dissolved in a 0.4 mol / L sodium carbonate-sodium bicarbonate buffer solution with a pH of 9.5 to make the keratin solution concentration 35 wt.%. The keratin solution was then aged at room temperature for 24 h, heated in a water bath at 90 °C for 2 h, and then centrifuged at 10,000 rpm for 20 min to remove bubbles, resulting in a uniformly mixed keratin spinning solution.

[0084] (2) Preparation of regenerated wool keratin fiber bundles

[0085] The above spinning solution was added to a storage tank and subjected to a process at 0.2 MPa and 25°C. Figure 1The spinneret, with 20 holes and a diameter of 50 μm, and a lateral spacing of 10 mm between adjacent holes, was extruded into a primary coagulation bath. The extrusion rate of the spinning solution was 500 μl / min. The primary coagulation bath was an aqueous solution containing 30 wt.% sodium dihydrogen phosphate, 0.5 wt.% cationic polyacrylamide, and 1 wt.% glycerol. The pH of the coagulation bath was adjusted to 2 with acetic acid, the coagulation temperature was 25°C, and the coagulation time was 3 min. After exiting the primary coagulation bath, the fiber bundle was drawn to a ratio of 0.2 and then entered a secondary coagulation bath containing a 15 wt.% sodium dihydrogen phosphate aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 25°C, and the coagulation time was 3 min. After exiting the secondary coagulation bath, the fiber bundles were drawn to a ratio of 3, and then placed in a tertiary coagulation bath containing a 10 wt.% sodium dihydrogen phosphate aqueous solution. The pH of the coagulation bath was 2, the coagulation temperature was 25℃, and the coagulation time was 3 minutes. This process was repeated multiple times, yielding approximately 8000 meters of fiber. The mass ratio of each coagulation bath to fiber was approximately 2500:1. After each spinning cycle, a few drops of hydrochloric acid were added to adjust the pH of the three coagulation baths back to 2, ensuring consistent coagulation conditions. After exiting the tertiary coagulation bath, the keratin fiber bundles were drawn to a ratio of 1.3. The keratin fiber bundles were then oxidized in an aqueous solution containing 10% v / v H₂O₂ at a temperature of 35℃ for 1.5 minutes. After exiting the oxidation bath, the fibers were drawn to a ratio of 2. The fiber bundles are then placed in an oil bath containing 10 wt.% glycerol at 35°C for 1.5 minutes. After exiting the oil bath, the fiber bundles are drawn to a ratio of 1.3. They then enter a washing bath containing 1 g / L sodium dodecylbenzenesulfonate, with the pH adjusted to 4 using acetic acid. The washing temperature is 40°C for 1.5 minutes. After exiting the washing bath, the fibers are drawn again and then placed in a 2-meter-long hot tunnel with a draw ratio of 1.1. The drying temperature is 80°C for 5 minutes. Finally, the fiber bundles are collected onto a spool by a winding machine at a speed of 30 m / min.

[0086] Comparative Example 1

[0087] The steps are basically the same as in Example 1, except that the coagulation bath in the keratin fiber bundle preparation process of Comparative Example 1 is only a single stage, and no cationic surfactant or oiling agent is added to the coagulation bath. The prepared regenerated wool keratin fiber bundles are mutually adhered, and the characterization of their cross-sectional morphology is shown in the attached figure. Figure 4 As shown.

[0088] Comparing Example 1 and Comparative Example 1, it can be seen that the fiber mechanical properties of the spun fibers obtained in Comparative Example 1 are lower than those obtained in Example 1. This is because, under the conditions in Comparative Example 1, the spinning streams adhere to each other due to surface tension. Furthermore, the attraction of van der Waals forces and the action of radial forces between the spinning streams cause them to form an adhesive state. This demonstrates that the method of the present invention can reduce the surface tension between keratin fiber bundles, reduce the fiber friction coefficient, improve lubricity, prevent keratin fiber bundles from adhering to each other, improve the problems of yarn doubling and breakage, and increase production capacity.

[0089] The keratin fiber bundles prepared in Examples 1-6 and Comparative Example 1 were subjected to performance tests. The test methods are as follows, and the measured data are shown in Table 1.

[0090] Test method:

[0091] The diameter of a single fiber in the prepared fiber bundle was measured using a fiber fineness tester of Shanghai Xinxian Instrument Co., Ltd., with 100 tests performed.

[0092] Table 1:

[0093]

[0094]

[0095] In Table 1, the keratin fiber bundles obtained in Examples 1-6 are well evenly distributed, which proves that the method of the present invention can avoid the adhesion between keratin fiber bundles, and the prepared regenerated keratin fibers have small diameter and bright luster.

[0096] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wet spinning process for regenerating keratin fiber tows, characterized in that, The wet spinning method comprises the following steps: Step S1, dissolving the keratin extracted from the keratin waste by dissolution and extraction into an alkaline solution to prepare a keratin spinning solution with a concentration of 15-45 wt.%, the molecular weight of the extracted keratin being between 45-110 kDa, and the pH value of the alkaline solution being controlled between 9.5-12; Step S2, primary coagulation: the keratin spinning solution obtained in step S1 is defoamed and then poured into a storage tank, and then extruded through a spinning pack into a primary coagulation bath to form a nascent fiber; Step S3, first drawing: the nascent fiber obtained in step S2 is subjected to first drawing with a draw ratio of 0-1; Step S4, secondary coagulation: the nascent fiber drawn in step S3 is subjected to secondary coagulation in a secondary coagulation bath, and the keratin fiber in the nascent fiber is further solidified and formed in the secondary coagulation bath; Step S5, second drawing: the nascent fiber treated in the secondary coagulation bath is subjected to second drawing with a draw ratio of 1-10; Step S6, tertiary coagulation: the nascent fiber drawn in step S5 is subjected to tertiary coagulation in a tertiary coagulation bath, and the keratin fiber in the nascent fiber is further solidified and formed in the tertiary coagulation bath; Step S7, third drawing: the nascent fiber treated in the tertiary coagulation bath is subjected to third drawing with a draw ratio of 1-10; Step S8, oxidation: the nascent fiber drawn in step S7 is subjected to oxidation in an oxidation bath, the temperature of the oxidation bath being controlled between 20-50℃, the oxidation bath being an aqueous solution containing 2-25 wt.% oxidizing agent, and the keratin in the nascent fiber re-forming disulfide bonds in the oxidation bath; Step S9, fourth drawing: the nascent fiber treated in the oxidation bath is subjected to fourth drawing with a draw ratio of 1-10; Step S10, water washing and oiling: the nascent fiber drawn in step S9 is subjected to water washing and oiling in a water washing bath containing oiling agent I, the temperature of the water washing bath being controlled between 20-45℃, the time being 0.1-3 min, and the addition amount of the oiling agent I in the water washing bath being 0.05-20 wt.%; Step S11, fifth drawing: the fiber treated in the water washing bath is subjected to fifth drawing with a draw ratio of 1-10; Step S12, drying and setting: the fiber drawn in step S11 is dried in a hot duct, the drying temperature being controlled between 60-150℃, and the time being 0.5-5 min; Step S13, winding: the fiber dried in step S12 is finally wound by a winding machine. The primary coagulation bath, the secondary coagulation bath and the tertiary coagulation bath are all alcohol solutions or inorganic salt solutions containing a surfactant and oiling agent II, the temperature of the coagulation bath being controlled between 20-50℃, and the pH value being controlled between 1.5-3.2; the concentration of the primary coagulation bath is 18-33 wt.%; the concentration of the secondary coagulation bath is 10-18 wt.%; and the concentration of the tertiary coagulation bath is 7-15 wt.%.

2. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, The surface active agent in the coagulation bath is a cationic surface active agent selected from one or more of dodecyl dimethyl benzyl ammonium chloride, cationic polyacrylamide, hexadecyl trimethyl ammonium chloride, octadecyl phosphate substituted amine, polyvinyl pyridine quaternary ammonium salt and dodecyl pyridine chloride, and the surface active agent is added in an amount of 0.05-10wt.%.

3. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, The oil agent II in the coagulation bath is selected from one or more of isononyl isononanoate, glycerol, n-decanoic acid, n-hexanoic acid and lauric acid, and the oil agent II is added in an amount of 0.05-10wt.%.

4. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, In step S2, the number of the spinning holes of the spinning plate in the spinning assembly is 10-100, the hole diameter R is 30-120μm, and the holes are uniformly dispersed in a single or multiple annular shape, and the lateral interval S between two adjacent holes is 5-25mm.

5. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, The alcohol used in the coagulation bath is selected from one or more of methanol, ethanol and propanol, the inorganic salt used is selected from one or more of calcium chloride, sodium sulfate, sodium dihydrogen phosphate, zinc sulfate and calcium sulfate, and the acid used for pH adjustment is selected from one or more of acetic acid, acetic acid and formic acid.

6. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, In step S2, the extrusion rate of the keratin spinning solution is 100-1000μl / min.

7. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, In step S8, the oxidizing agent of the oxidation bath is selected from one or more of manganese dioxide, potassium permanganate, hypochlorous acid, sulfur dioxide, peroxyacetic acid, hydrogen peroxide and sodium periodate.

8. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, The oil agent I in step S10 is selected from one or more of glycerol, polyethylene glycol and triethanolamine.

9. The wet spinning process for regenerating keratin fiber tow according to claim 1, characterized by, In step S1, the keratin spinning solution is prepared by the following method: A keratin modifier is added to the solution in which the keratin is dissolved to cleave the disulfide bonds in the keratin to form, the keratin modifier is selected from one or more of sodium bisulfite, sodium sulfite, L-cysteine and dithiothreitol, and the keratin modifier is added in an amount of 1-40% by weight of the keratin.

10. A regenerated keratin fiber strand, characterized in that, It is prepared by the wet spinning method of the regenerated keratin fiber bundle according to any one of claims 1 to 9, and the diameter of the single keratin fiber in the regenerated keratin fiber bundle is 5-18μm.

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