CN111893580B

CN111893580B - Keratin spinning solution and prepared keratin regenerated fiber

Info

Publication number: CN111893580B
Application number: CN202010554101.9A
Authority: CN
Inventors: 容敏智; 曹广盛; 章明秋
Original assignee: Sun Yat Sen University
Current assignee: Sun Yat Sen University
Priority date: 2020-06-17
Filing date: 2020-06-17
Publication date: 2021-08-24
Anticipated expiration: 2040-06-17
Also published as: CN111893580A

Abstract

The invention discloses a keratin spinning solution and a keratin regenerated fiber prepared from the same, wherein the keratin spinning solution is prepared by reacting the following raw materials in water: the wool fabric comprises wool, a protein denaturant, a reducing agent and a toughening agent, wherein the protein denaturant is one or more of sodium dodecyl benzene sulfonate, sodium hexadecyl sulfate or sodium dodecyl sulfate. The invention does not need to use reagents such as urea or lithium bromide and the like, can be directly used for spinning to prepare regenerated fibers without any purification treatment, has simpler preparation method and higher utilization rate of wool keratin. The invention can reduce the damage of the keratin main chain, does not contain urea or lithium bromide, and the obtained keratin solution is matched with a proper amount of toughening agent for spinning to obtain regenerated fiber with the similar mechanical property with natural wool, and the keratin regenerated fiber has high keratin content.

Description

Keratin spinning solution and prepared keratin regenerated fiber

Technical Field

The invention relates to the technical field of animal protein regenerated fibers, and more particularly relates to a keratin spinning solution and a keratin regenerated fiber prepared from the same.

Background

With the aggravation of environmental pollution and the consumption of natural resources, the recycling and preparation of wastes into recycled materials are increasingly and widely regarded. The wool is used as a high-end textile raw material, and has good wearing comfort, heat preservation and air permeability. However, during textile processing such as scouring, carding, combing and spinning, thousands of tons of waste wool are produced each year. In addition, a large amount of short and thick waste wool is generated in the production process of mutton, and the short and thick waste wool can only be buried or burnt as garbage. Under the background that natural resources are in short supply and synthetic fibers cannot meet the increasing requirements of high-grade animal fiber textiles, the waste wool is recycled and developed into the regenerated animal protein fiber which can be used as the textile, and huge economic benefit and environmental benefit are generated.

The traditional wool dissolving method usually needs to adopt solvents such as urea or lithium bromide with the concentration of 42-50% to destroy a great amount of hydrogen bonds existing among wool keratin molecules, adjust the pH value of the solution to be alkaline, and add a small amount of sodium dodecyl sulfate and keratin to form micelles to prepare a stable solution. The solution prepared by the method has low keratin concentration (generally only 5 percent) and cannot meet the requirement of direct spinning. If the concentration is increased, the keratin is difficult to be fully dissolved, and the mechanical property of the regenerated fiber is influenced. In order to prepare high-concentration keratin spinning solution meeting spinning requirements, generally, wool is dissolved, then wool residues which are not dissolved in the solution are separated and removed, and then small molecules such as urea or lithium bromide are removed by methods such as dialysis or isoelectric point adjustment, and the two purification processes can cause the loss of keratin, and only about 70% of keratin can be recovered at most. The purified keratin must be re-dissolved to form a spinning solution before the next spinning step can be carried out. Therefore, the keratin spinning solution prepared by recycling wool in the prior art has complex method, needs the processes of dissolution, purification, redissolution and the like, and has serious raw material loss. Furthermore, the regenerated keratin fibers obtained by spinning have poor mechanical properties and cannot meet the requirements of strength and toughness at the same time. For example, chinese patent application CN103205861A discloses a wool keratin spinning solution, which adopts a sodium sulfide/urea/sodium dodecyl sulfate method to dissolve wool, the method for preparing the keratin spinning solution is complicated, and the mechanical properties of the keratin regenerated fiber obtained by spinning are poor.

Therefore, the development of a keratin spinning solution which has a simpler preparation method and is beneficial to improving the mechanical property of the regenerated keratin fiber is needed.

Disclosure of Invention

The keratin spinning solution is simple in preparation method, can be directly prepared into high-concentration and high-viscosity spinning solution, is directly applied to wet spinning, can reduce damage of a keratin main chain, does not contain urea or lithium bromide, is beneficial to improving the mechanical property of the prepared keratin regenerated fiber, and obtains good strength and toughness.

Another object of the present invention is to provide a regenerated keratin fiber.

In order to solve the technical problems, the invention adopts the technical scheme that:

a keratin spinning solution is prepared by reacting the following raw materials in parts by weight in water:

the protein denaturant is one or more of sodium dodecyl benzene sulfonate, sodium hexadecyl sulfate or sodium dodecyl sulfate.

The wool may be waste wool.

The inventor researches and discovers that when urea or lithium bromide is adopted to dissolve wool in the prior art, the dissolution needs to be carried out under high temperature conditions, and the alkaline environment and the high-concentration urea and lithium bromide can destroy the keratin main chain to a certain extent and reduce the keratin molecular weight. The keratin molecular weight is reduced, so that the regenerated keratin fiber obtained by spinning has poor mechanical property and cannot meet the requirements of strength and toughness at the same time.

The inventors have further studied and found that wool can be sufficiently dissolved by merely increasing the amount of a surfactant such as sodium lauryl sulfate used as a protein denaturing agent and adding a reducing agent without destroying hydrogen bonds with a reagent such as urea or lithium bromide, and a wool keratin solution having a concentration of up to 20% and usable directly for wet spinning can be prepared. In the wool dissolving process, sodium dodecyl sulfate and the like are used as surfactants, and hydrophilic terminals of the surfactants are-SO₄ ^-2Can form hydrogen bonds with keratin molecules and form a competitive relationship with the hydrogen bonds in the structure of the keratin, thereby achieving the purpose of destroying the hydrogen bonds inside wool, and the hydrophobic end forms a hydrophobic effect with oily groups in the keratin, so as to break the structure of a hydrophobic area inside the keratin, lead a reducing agent to further enter the inside of the wool to destroy disulfide bonds and fully dissolve the wool. After the keratin is dissolved, the surfactant forms micelles with the keratin through hydrophobic effect, and hydrophilic groups in the keratin and hydrophilic ends of the surfactant are fully exposed, so that the solubility of the keratin in water is greatly improved.

According to the spinning process requirement, the high-concentration (up to 20%) keratin solution is prepared by fully dissolving the waste wool, and the solution can be directly used for preparing regenerated fibers without any purification treatment, so that the problems of low concentration of the keratin solution, raw material loss caused by purification treatment, resource waste, complex process and the like in the traditional method are solved, and the high-efficiency recycling of the waste wool is realized.

In addition, the invention can reduce the damage of the keratin main chain, does not contain urea or lithium bromide and is beneficial to improving the mechanical property of the prepared keratin regenerated fiber. The obtained keratin dissolved solution is matched with a proper amount of toughening agent to obtain spinning dope, and the conventional post-crosslinking treatment is carried out after spinning, thus obtaining the keratin regenerated fiber with good strength and toughness.

Preferably, the protein denaturant is 4-10 parts.

Preferably, the mass ratio of the wool to the water is 1: 3-8.45.

Preferably, the reaction temperature is 60-80 ℃, and the reaction time is 12-24 h.

Preferably, the protein denaturant is sodium lauryl sulfate.

Preferably, the reducing agent is one or more of dithiothreitol, thioglycolic acid, sodium sulfide or sodium borohydride.

Preferably, the reducing agent is dithiothreitol and/or thioglycolic acid.

Preferably, the toughening agent is one or more of polyvinyl alcohol, hydroxypropyl cellulose or poly rotaxane graft polycaprolactone.

Preferably, the molecular weight Mw of the polyvinyl alcohol is 31000-50000 g/mol.

Preferably, the substitution degree of the hydroxypropyl cellulose is 60-66%.

Preferably, the molecular weight Mw of the polyrotaxane grafted polycaprolactone is 300000-400000 g/mol. Optionally, in the polyrotaxane grafted polycaprolactone, the content of polycaprolactone is 75 wt%. The raw material of the polyrotaxane grafted polycaprolactone can be polycaprolactone with the molecular weight Mw of 3000 g/mol. The polyrotaxane-grafted polycaprolactone can be obtained commercially.

The invention also provides a keratin regenerated fiber, which is obtained by carrying out wet spinning and post-crosslinking treatment on the keratin spinning solution.

The wet spinning method comprises the following steps: and (3) defoaming the keratin spinning solution, and spinning by taking an ammonium chloride saturated solution as a coagulating bath to obtain the nascent fiber.

The post-crosslinking treatment comprises the following steps: and soaking the nascent fiber in an aqueous solution of glutaraldehyde, washing and drying after crosslinking is finished, and obtaining the keratin regenerated fiber. The temperature of the post-crosslinking may be room temperature. The concentration of the aqueous solution of glutaraldehyde may be 5%. The soaking time of the post-crosslinking treatment can be 1-2 min.

Compared with the prior art, the invention has the beneficial effects that:

the method can directly prepare the high-concentration keratin stock solution meeting the spinning process requirements without using reagents such as urea or lithium bromide and the like, can be directly used for spinning to prepare regenerated fibers without any purification treatment, and has a simpler preparation method of the keratin spinning stock solution. The problems of low concentration of the keratin solution, raw material loss caused by purification treatment, resource waste, complex process and the like in the traditional method are solved, and the high-efficiency recycling of the waste wool is realized.

The invention can reduce the damage of the keratin main chain, does not contain urea or lithium bromide and is beneficial to improving the mechanical property of the prepared keratin regenerated fiber. The obtained keratin dissolved solution is matched with a proper amount of flexibilizer to obtain spinning dope, and the spinning dope is subjected to conventional post-crosslinking treatment, so that the regenerated animal protein fiber which has excellent mechanical properties (has good strength and toughness) and takes wool keratin as a main matrix material can be prepared.

Drawings

Fig. 1 is an SEM picture of the regenerated keratin fiber produced in example 1 of the present invention.

Fig. 2 is an XRD spectrum of the regenerated keratin fiber prepared in example 1 of the present invention.

Detailed Description

The present invention will be further described with reference to the following embodiments.

The raw materials in the examples are all commercially available;

in the examples and comparative examples, the polyvinyl alcohol was obtained from model 363138 of Sigma-aldrich Sigma Aldrich trade Co., Ltd, the molecular weight Mw was 31000-50000 g/mol, and the degree of hydrolysis was 98-99%; the hydroxypropyl cellulose is purchased from Shanghai biological engineering Co., Ltd.A 600519, and the substitution degree is 60-66%; the polyrotaxane grafted polycaprolactone is purchased from Tianjin micro-Rui supermolecule materials science and technology Limited, model U111562G, the molecular weight is 300000-400000 g/mol, and the PCL content is 75%.

Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1

This example provides a keratin spinning dope, and a keratin regenerated fiber obtained by wet spinning.

The preparation method of the keratin spinning solution comprises the following steps:

20g of waste wool, 10g of sodium dodecyl benzene sulfonate, 5g of dithiothreitol and 62.5g of distilled water are added into a three-mouth bottle with a condensation reflux device and stirring magnetons under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

The preparation method of the keratin regenerated fiber comprises the following steps:

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking treatment for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 88.9%.

Example 2

20g of waste wool, 10g of sodium hexadecylsulfate, 5g of dithiothreitol and 62.5g of distilled water are added into a three-neck flask with a condensation reflux device and a stirring magneton under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 3

20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 62.5g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 4

under the protection of nitrogen, 20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 60g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking treatment for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 80.0%.

Example 5

20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 64g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 1g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 95.2%.

Example 6

under the protection of nitrogen, 15g of waste wool, 4g of sodium dodecyl sulfate, 2g of dithiothreitol and 76.5g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 18h at 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking treatment for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 85.7%.

Example 7

under the protection of nitrogen, 10g of waste wool, 2g of sodium dodecyl sulfate, 1g of dithiothreitol and 84.5g of distilled water are added into a three-mouth bottle with a condensation reflux device and a stirring magneton, and stirred and refluxed at a high speed for 12 hours at the temperature of 60 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 8

20g of waste wool, 10g of sodium dodecyl sulfate, 5g of thioglycolic acid and 62.5g of distilled water are added into a three-necked flask with a condensation reflux device and a stirring magneton under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 9

20g of waste wool, 10g of sodium dodecyl sulfate, 5g of sodium sulfide and 62.5g of distilled water are added into a three-mouth bottle with a condensation reflux device and a stirring magneton under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 10

under the protection of nitrogen, 20g of waste wool, 10g of sodium dodecyl sulfate, 5g of sodium borohydride and 62.5g of distilled water are added into a three-necked bottle with a condensation reflux device and a stirring magneton, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 2.5g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Example 11

under the protection of nitrogen, 20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 60g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 5g of polyvinyl alcohol, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning solution.

Example 12

under the protection of nitrogen, 20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 60g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 5g of polyrotaxane grafted polycaprolactone, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in 5% glutaraldehyde water solution at room temperature for 1min for post-crosslinking treatment, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 80.0%.

Comparative example 1

The present comparative example provides a keratin spinning dope, and a keratin regenerated fiber obtained by wet spinning.

20g of waste wool, 29g of urea, 2g of sodium dodecyl sulfate, 5g of dithiothreitol and 41.5g of distilled water are added into a three-mouth bottle with a condensation reflux device and stirring magnetons under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. After the wool is fully dissolved, 2.5g of hydroxypropyl cellulose is added, heating is stopped, the temperature is naturally reduced to room temperature, and the mixture is kept fully stirred, so that light gray pasty wool keratin spinning solution which is not fully dissolved is obtained.

Comparative example 2

20g of waste wool, 35g of lithium bromide, 2g of sodium dodecyl sulfate, 5g of dithiothreitol and 35.5g of distilled water are added into a three-mouth bottle with a condensation reflux device and stirring magnetons under the protection of nitrogen, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. After the wool is fully dissolved, 2.5g of hydroxypropyl cellulose is added, heating is stopped, the temperature is naturally reduced to room temperature, and the mixture is kept fully stirred, so that light gray pasty wool keratin spinning solution which is not fully dissolved is obtained.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber to obtain the regenerated fiber with the wool keratin content of 88.9%.

Comparative example 3

under the protection of nitrogen, 20g of waste wool, 10g of sodium dodecyl sulfate, 5g of dithiothreitol and 65g of distilled water are added into a three-neck flask with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 24 hours at 80 ℃. And after the wool is fully dissolved, stopping heating to naturally cool the wool to room temperature and keeping fully stirring to obtain the light gray wool keratin spinning solution.

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then soaking the nascent fiber in a 5% glutaraldehyde water solution at room temperature for post-crosslinking for 1-2 min, taking out the crosslinked regenerated fiber, washing the regenerated fiber with distilled water, and naturally drying the regenerated fiber in the air to obtain the regenerated fiber with the wool keratin content of 100%.

Comparative example 4

centrifuging the obtained spinning solution at 1000rpm for 10min for degassing bubble treatment, and wet spinning with saturated ammonium chloride solution as coagulating bath to obtain nascent fiber. And then washing the nascent fiber with distilled water, and naturally drying to obtain the regenerated fiber with the wool keratin content of 88.9%.

Comparative example 5

under the protection of nitrogen, 10g of waste wool, 36.25g of urea, 2.5g of dithiothreitol and 50g of distilled water are added into a three-mouth bottle with a condensation reflux device and stirring magnetons, and stirred and refluxed at a high speed for 24 hours at a temperature of 80 ℃. And after the wool is fully dissolved, adding 1.25g of hydroxypropyl cellulose, stopping heating, naturally cooling to room temperature, and keeping fully stirring to obtain the light gray wool keratin spinning stock solution.

Test method

And (3) testing mechanical properties: using standard ISO11566, the spacing is 25mm and the drawing rate is 5mm^-1. Each sample measurement was tested in parallel for 50 specimens; the tensile strength and elongation at break were measured.

And (3) morphology testing: SEM morphology characterization was performed using HITACHI model S-4800, platinum was sprayed on the surface of the fiber, and the acceleration voltage was 10 kV.

XRD test: XRD measurements were performed with a D8 ADVANCE X-ray diffractometer (WAXR, Cu K)_αradiation, lambda is 0.154nm, scanning range is 5-80 deg., and scanning speed is 10 deg. min^-1,Bruker Corporation,Genrmany)。

Test results

The keratin solution with the concentration and viscosity required by wet spinning can be prepared under the neutral condition according to the spinning process requirement, so that the keratin solution can be directly used for spinning without purification. The keratin spinning dope prepared in examples 1 to 12 has a high keratin concentration, wherein the concentrations of examples 1 to 5 and 8 to 12 are as high as 20%.

The keratin spinning solution obtained in the embodiment 1 to 12 is spun and combined with a simple post-crosslinking treatment process to prepare the regenerated animal protein fiber which has excellent mechanical properties and takes wool keratin as a main matrix material (the keratin content is more than 88.9%), and the spinning and post-treatment processes are simple and convenient to operate. As shown in Table 1, the regenerated keratin fibers prepared in the embodiments 1 to 12 have tensile strength higher than 7cN/tex, elongation at break higher than 20%, and good mechanical properties. In the prior art, the spinnability of a pure keratin solution is poor, and the obtained regenerated material has low mechanical property, so that the wool keratin can only be used as a secondary component of the regenerated material.

And (3) morphology testing results: as shown in fig. 1, example 1 resulted in a smooth surfaced fiber filament having a diameter of about 30 microns. XRD test results: in fig. 2, 9 ° represents α -helix structure and 20 ° represents β -sheet, and the regenerated fiber obtained in example 1 has decreased α -helix and increased β -sheet compared to the original wool.

Comparative examples 1 and 2 are conventional methods, and require the use of high concentrations of reagents such as urea and lithium bromide to break down a large number of hydrogen bonds present between wool keratin molecules, and also require adjustment of the pH to alkaline and addition of a small amount of sodium dodecyl sulfate to form micelles with keratin to produce a stable keratin solution. The solution reaction needs to be carried out under the high-temperature condition, the alkaline environment and the high-concentration urea or lithium bromide can destroy the keratin main chain to a certain extent, and the keratin molecular weight is reduced. In addition, the high concentration of urea and lithium bromide directly affects the solidification process of the regenerated fiber, and reduces the mechanical property of the regenerated fiber. As shown in table 1, the tensile strength was insufficient in both comparative example 1 and comparative example 2.

Comparative example 3, which was post-crosslinked without using a toughening agent, had poor toughness despite the relatively high mechanical strength of the resulting regenerated fiber. Comparative example 4 uses a toughening agent but does not crosslink, and the toughness of the regenerated fiber is improved to a certain extent, but the mechanical strength is poor and cannot meet the practical requirements.

Comparative example 5 in the wool dissolving process, a surfactant such as sodium dodecyl sulfate, etc. was not used, and thus a large amount of urea or lithium bromide was required to break the hydrogen bonds, but a high-concentration sufficiently dissolved keratin solution could not be obtained, and the mechanical strength and toughness of the regenerated fiber prepared were reduced due to the influence of the high-concentration urea or lithium bromide on the coagulation process of the regenerated fiber.

TABLE 1 mechanical Properties of regenerated Keratin fibers obtained in examples 1 to 12 and comparative examples 1 to 5

Sample (I)	Tensile Strength (cN/tex)	Elongation at Break (%)
			Example 1	8.68	41.09
Example 2	8.52	43.05
			Example 3	9.44	39.72
Example 4	7.06	68.19
			Example 5	10.98	22.72
Example 6	7.66	56.24
			Example 7	7.18	63.02
Example 8	8.56	42.28
			Example 9	8.34	35.42
Example 10	8.29	37.84
			Example 11	10.85	22.32
Example 12	7.02	64.54
			Comparative example 1	4.74	24.24
Comparative example 2	4.98	30.74
			Comparative example 3	12.55	4.40
Comparative example 4	0.57	22.65
			Comparative example 5	4.85	8.71

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The keratin spinning solution is characterized by being prepared by reacting the following raw materials in water in parts by weight:

the protein denaturant is one or more of sodium dodecyl benzene sulfonate, sodium hexadecyl sulfate or sodium dodecyl sulfate; the reducing agent is one or more of dithiothreitol, thioglycollic acid, sodium sulfide or sodium borohydride; the toughening agent is one or more of polyvinyl alcohol, hydroxypropyl cellulose or poly rotaxane grafted polycaprolactone.

2. The keratin spinning dope of claim 1, wherein the protein denaturant is 4 to 10 parts.

3. The keratin spinning dope of claim 1, wherein the reaction temperature is 60 to 80 ℃ and the reaction time is 12 to 24 hours.

4. The keratin spinning dope of claim 1 or 2, wherein the protein denaturant is sodium lauryl sulfate.

5. The keratin spinning dope of claim 1, wherein the molecular weight Mw of the polyvinyl alcohol is 31000-50000 g/mol.

6. The keratin spinning dope of claim 1, wherein the substitution degree of the hydroxypropyl cellulose is 60 to 66%.

7. The keratin spinning dope of claim 1, wherein the polyrotaxane grafted polycaprolactone has a molecular weight Mw of 300000-400000 g/mol.

8. A regenerated keratin fiber obtained by wet spinning the keratin spinning dope of any one of claims 1 to 7 and post-crosslinking the resulting product.