Preparation method of collagen spinning solution, collagen spinning solution and application thereof

Abstract

The present application relates to the field of fiber technology, and specifically discloses a method for preparing a collagen spinning solution, a collagen spinning solution and its application. The preparation method selects relatively cheap water as a solvent, animal leather as a raw material, and alkali as a dissolving aid; after dissolution, the supernatant is taken, and a divalent metal ion Ca is used to dissolve the collagen. 2+ As a cross-linking agent, it causes collagen to lose its water solubility and precipitate, achieving the purpose of removing most of the water; then acid is added, the acid combines with calcium, the collagen regains its water solubility, and forms a macromolecular complex with the added carrageenan to form an ion-sensitive spinning solution, which is used for fibers with different collagen concentrations produced by the wet spinning process.

Description

Technical Field

[0001] The present application relates to the field of fiber technology, and more specifically, to a method for preparing a collagen spinning solution, a collagen spinning solution and its application. Background Art

[0002] Collagen is a white, opaque, unbranched fibrous protein. It is a biological polymer composed of animal cells. It is widely present in the bones, tendons, muscle sheaths, ligaments, fascia, cartilage and skin of animals. It has excellent biocompatibility, degradability and biological activity.

[0003] Existing collagen is generally difficult to spin directly. It usually needs to be made into a collagen spinning solution and then compounded with other cellulose before spinning. Combining collagen with cellulose through regeneration or derivatization methods to prepare composite fibers can make cellulose fibers comfortable and durable, thereby obtaining high-value-added textile fabrics. At present, the common processing method for composite fibers formed by combining collagen and cellulose is to first "dissolve" the cellulose and collagen separately with corresponding solvents, then mix the obtained cellulose spinning solution and collagen spinning solution, and then wet-spin the mixed spinning solution to obtain long fiber materials.

[0004] Among them, the collagen solvents commonly used at home and abroad mainly include fluoroalcohols such as hexafluoroisopropanol, acidic systems such as acetic acid and hydrochloric acid, alkaline solutions, enzyme solutions and ionic liquids. For example, the invention patent with patent publication number CN107190341A discloses a method for preparing regenerated collagen fibers, which uses alkaline treatment and enzyme treatment to solubilize insoluble collagen; the invention patent application with patent publication number CN111501121A discloses a method for preparing collagen fibers by wet spinning, which uses sodium acetate / acetic acid buffer solution to dissolve collagen.

[0005] When dissolving collagen, these methods often require a large amount of medium (water) to dilute the acid or base, thereby minimizing denaturation caused by excessive acid or base concentrations. However, the resulting collagen spinning solution contains a high water content, which makes the collagen easily aggregated. This means that the collagen microfibrils are destroyed during the dissolution process, making it difficult to stably disperse in the alkaline cellulose spinning solution. This results in poor spinnability of the resulting mixed spinning solution. Summary of the Invention

[0006] In order to improve the stability of collagen spinning solution to ensure the spinnability of the mixed spinning solution, the present application provides a preparation method of collagen spinning solution, collagen spinning solution and application.

[0007] In a first aspect, the present application provides a method for preparing a collagen spinning solution, comprising the following steps:

[0008] Dissolution: soaking the raw material of the collagen in an alkaline solution with a concentration of 2-15 wt %, with the weight ratio of the raw material of the collagen to the alkaline solution being 1:3.5-7, and harvesting the crude collagen solution after the raw material of the collagen is fully dissolved;

[0009] Precipitation: Let the crude collagen solution stand until layers are separated, take the supernatant and add calcium chloride solution to harvest the precipitate;

[0010] Decalcification: Add acid to the precipitate until the precipitate is fully dissolved, and adjust the pH value to 5.5-8 to obtain decalcified collagen solution;

[0011] Complexation: Take decalcified collagen solution, add carrageenan, stir evenly and let it stand to defoam, and then harvest the collagen spinning solution.

[0012] The preparation method of the present application uses a set amount of alkali solution to dissolve the glue raw material. The alkali solution will destroy the peptide bonds in the protein, hydrolyzing the protein into small molecular amino acids, which are water-soluble. The reaction equation is as follows:

[0013]

[0014] Among them, if the concentration of the alkali solution is too low, its dissolution efficiency of the rubber raw material is low, and the water content of the obtained crude collagen solution is also high, which greatly increases the acquisition of collagen; if the concentration of the alkali solution is too high, although it can quickly and effectively dissolve collagen, the collagen solution is denatured in the alkali solution system. For this reason, this application strictly controls the concentration and dosage of the alkali solution so that the collagen in the rubber raw material is effectively dissolved and the water content of the obtained crude collagen solution is low.

[0015] In addition to collagen that can be dissolved by alkali, the raw material of collagen also contains other insoluble substances. Therefore, the crude collagen solution obtained contains non-collagenous substances. Standing helps the non-collagenous substances to precipitate, and the supernatant is the collagen solution. However, the collagen treated with alkali contains carboxyl groups, which has poor stability. Therefore, this application uses calcium chloride to cross-link the collagen. 2+ The flocculent solid formed after cross-linking loses its water solubility and precipitates downward. When no precipitation occurs, the upper solution is poured out and the harvested precipitate contains the calcium salt of collagen. Then acid is added to the precipitate. The H + The calcium in the precipitate can be replaced, and the precipitate can be transformed into water-soluble collagen again. The above steps can greatly reduce the water content of the collagen solution, thereby meeting the concentration requirements of spinning.

[0016] On this basis, the present application adds carrageenan to the decalcified collagen solution obtained after acid decalcification. On the one hand, carrageenan can complex collagen and increase the stability of collagen in aqueous solution; on the other hand, the complex formed by carrageenan complexing collagen can effectively improve the situation that the fibers formed after collagen spinning are easy to break; in addition, carrageenan has good ion sensitivity, and it complexes with collagen to form an ion-sensitive spinning solution, thereby effectively improving the problem that collagen is difficult to spin in spinning equipment. The collagen spinning solution thus prepared can not only effectively maintain the performance of collagen, but also make the entire spinning solution system have excellent stability and ion sensitivity to ensure its spinnability, and can be well applied to fibers with different collagen concentrations produced by wet spinning process.

[0017] Preferably, the glue raw material is derived from one or more of animal bones, tendons, muscle sheaths, ligaments, fascia, cartilage and skin.

[0018] Preferably, the glue raw material is derived from cowhide.

[0019] By adopting the above technical solution, animal bones, tendons, muscle sheaths, ligaments, fascia, cartilage and skin are rich in collagen. The present application can effectively extract collagen from the above-mentioned collagen raw materials by using an alkali solution of appropriate concentration. Among them, the collagen content in cowhide is as high as 80%, making it the preferred source of collagen.

[0020] Preferably, in the dissolving step, the dissolving temperature of the glue raw material is controlled to be ≤20°C.

[0021] By adopting the above technical solution, collagen is more sensitive to heat and has poor stability in alkaline solution. Therefore, controlling the temperature at ≤20°C can effectively ensure the activity of collagen.

[0022] Preferably, the alkali solution is one or more of sodium hydroxide and potassium hydroxide.

[0023] By adopting the above technical solution, sodium hydroxide and potassium hydroxide have strong alkalinity and can better dissolve the collagen in the glue raw material; in addition, the sources of these two alkalis are wide and easy to obtain, which is convenient for enterprises to produce and manufacture.

[0024] Preferably, in the precipitation step, a calcium chloride solution with a concentration of 30±5wt% is slowly added to the supernatant of the crude collagen solution while stirring until flocculent solids stop being produced, and the solution is allowed to stand until stratification, the supernatant is discarded, and the harvested flocculent solids are washed with pure water to obtain the precipitate with a water content of ≤30wt%.

[0025] By adopting the above technical solution, a high concentration of calcium chloride solution helps to quickly increase the concentration of divalent calcium ions in the collagen solution. Combined with the method of slowly adding while stirring, the calcium ions can be evenly dispersed in the collagen solution and effectively cross-linked. The resulting flocculent solids can be separated into layers after standing, making it easy to obtain the flocculent solids, thereby removing as much water as possible from the collagen solution.

[0026] Preferably, the acid is one or more of sulfuric acid, hydrochloric acid, nitric acid, citric acid, acetic acid and tartaric acid.

[0027] By adopting the above technical solution, the above acids all have strong acidity, and their H + It can effectively replace the calcium in the flocculent solids and transform them into water-soluble collagen again.

[0028] Preferably, in the decalcification step, the pH value is adjusted with citric acid or sodium hydroxide.

[0029] By adopting the above technical solution, during decalcification, if the precipitate is alkaline, citric acid is added. Compared with other acid regulators, citric acid is an organic acid with strong acidity. While adjusting the pH, it can also further stabilize the calcium ions removed from the collagen to form calcium citrate precipitation, thereby helping to obtain high-purity collagen. If the precipitate is acidic, sodium hydroxide is added. The OH- of sodium hydroxide can effectively neutralize the excess H in the system. + , ensure that the pH of the system meets the requirements.

[0030] Preferably, in the complexing step, the carrageenan is added at a weight ratio of collagen to carrageenan of 10-36:64-90.

[0031] Preferably, in the collagen spinning solution, the weight ratio of the complex to water is 16-33:84-77.

[0032] By adopting the above technical solution, if the content of carrageenan is too high, the fiber properties of the collagen spinning solution may not meet the expectations; if the content of carrageenan is too low, the spinnability of the obtained collagen spinning solution is poor. Therefore, after a large number of experiments, the present application has found that the weight ratio of collagen to carrageenan is preferably 10-36:64-90.

[0033] In addition, the moisture content in the complex should not be too high. This application limits the weight ratio of the complex to water to 16-33:84-77, which can effectively reduce the moisture in the collagen spinning solution. In addition, the collagen spinning solution obtained can be directly used for spinning and has good spinnability.

[0034] In a second aspect, the present application provides a collagen spinning solution prepared by the above-mentioned preparation method. The collagen spinning solution prepared by the above-mentioned method has good stability and spinnability and can be well applied in industries such as spinning.

[0035] In a third aspect, the present application provides a collagen fiber, which is made from the collagen spinning solution. The fiber made from the collagen spinning solution has the good properties of collagen.

[0036] In a fourth aspect, the present application provides that the applications of the above-mentioned collagen fibers include but are not limited to the following fields.

[0037] Used in non-woven fields, such as facial masks, sanitary napkins, diapers, underarm patches, etc.

[0038] Applied in the textile field, such as underwear, socks, shorts, clothing fabrics and bedding, collagen fiber is more suitable for spinning and producing protein fiber than general plant protein fiber, and has excellent moisturizing properties, good affinity with human skin, and is comfortable to wear. It is suitable for the development of bedding, shirts, knitted underwear, socks and other products.

[0039] Used in the medical field, such as Band-Aids, bandages, dressings, etc., it has good anti-seepage and healing functions.

[0040] It is used in the food field, such as packaging bags for food preservatives and fruit preservatives, and can also be used in artificial leather.

[0041] Applied in the papermaking industry, it is mainly in the form of fibers and composite products with plant fibers to improve paper strength, water absorption, air permeability, tightness and whiteness.

[0042] Applied in composite materials and nanomaterials, collagen fibers have good film-forming properties in addition to being blended and spun with other polymer materials.

[0043] In summary, this application has the following beneficial effects:

[0044] 1. The preparation method of this application uses relatively cheap water as solvent and alkali as dissolving aid; after dissolving the raw material of glue, take the supernatant and use divalent metal ion Ca 2+ As a cross-linking agent, the collagen loses its water solubility and precipitates, achieving the purpose of removing most of the water; then acid is added, the acid combines with calcium, the collagen regains its water solubility, and forms a macromolecular complex with the added carrageenan to form an ion-sensitive spinning solution, which can not only effectively maintain the performance of collagen, but also make the entire spinning solution system have excellent stability and ion sensitivity to ensure its spinnability, and thus can be better applied to fibers with different collagen concentrations produced by the wet spinning process.

[0045] 2. This application further limits the usage ratio of the rubber raw material to the alkali solution and the weight ratio of the collagen to the carrageenan, thereby further improving the stability and spinnability of the collagen spinning solution.

[0046] 3. The collagen spinning solution prepared in this application can be well applied to fiber preparation, thereby facilitating the expansion of collagen recycling and utilization and achieving sustainable development of resources. DETAILED DESCRIPTION

[0047] The existing collagen solution formed after alkali treatment has the problems of high water content and poor collagen stability, so it is often used to prepare gel. However, the present application is to obtain a spinnable collagen spinning solution, which requires greatly reducing the water content in the solution to ensure the effective spinning content of the collagen, and at the same time, it is necessary to make the structure of the collagen meet the spinning requirements. To this end, the present application provides a new method for preparing a collagen spinning solution with high stability and spinnability. The collagen spinning solution prepared in this way can be directly used in the spinning process to be spun into collagen fibers.

[0048] In the preparation method of the present application, raw materials and reagents are all commercially available products.

[0049] The raw materials for the glue can be derived from one or more of animal bones, tendons, muscle sheaths, ligaments, fascia, cartilage, and skin, and can be specifically recycled from waste materials such as slaughterhouses and food processing plants. This application further illustrates this using cowhide as an example, as cowhide contains up to 80% collagen, which can be harvested at a higher level, helping to reduce the cost of collagen recycling and fiber production for businesses.

[0050] The present application is further described in detail below with reference to the following examples and comparative examples.

[0051] Example

[0052] Example 1

[0053] 1. Preparation of collagen spinning solution

[0054] The method of spinning collagen dope in this embodiment comprises the following steps:

[0055] (1) Dissolution:

[0056] 1 kg of cowhide was soaked in 3.5 kg of 2 wt% alkali solution at a temperature of ≤ 20° C. (specifically 20° C.) for 3 hours to fully dissolve the collagen in the cowhide, and a crude collagen solution was obtained. The alkali solution may be one or more of NaOH and KOH. In this embodiment, NaOH is used as an example.

[0057] (2) Precipitation:

[0058] The crude collagen solution was allowed to stand until layers were separated, and a 30 wt% (fluctuation within the range of 30 ± 5 wt%) calcium chloride solution was slowly added to the supernatant while stirring until flocculent solids ceased to form. The solution was allowed to stand again until layers were separated, and the supernatant was discarded. The flocculent solids were washed twice with purified water to obtain a precipitate having a water content of 30 wt%.

[0059] (3) Decalcification:

[0060] Acid is added to the precipitate until the precipitate is fully dissolved, and the pH is adjusted to 6.0 to obtain a decalcified collagen solution. The type of acid added includes one or more of sulfuric acid, hydrochloric acid, nitric acid, citric acid, acetic acid, and tartaric acid. Due to the different types and properties of the acid, it is usually slowly added to the cross-linked collagen in the form of an acid solution or an acid aqueous solution until it is completely dissolved. The addition is stopped. In this embodiment, citric acid is used to dissolve the precipitate and adjust the pH. If excessive acid is added, sodium hydroxide is used to adjust the pH to 6.0.

[0061] (4) Complexation:

[0062] A small amount of the collected decalcified collagen solution was freeze-dried into a powder, and the actual collagen content in the decalcified collagen solution was calculated. Carrageenan was added to the remaining decalcified collagen solution for a complexation reaction. Carrageenan was added at a weight ratio of collagen to carrageenan of 10:90, and the solution was stirred at a stirring speed of 15 rpm (which can fluctuate within the range of 10-20 rpm) for 4±0.1 h. After thorough stirring, the solution was allowed to stand for defoaming. The complexation reaction was carried out in water, and the weight ratio of the complex to water was 16:84. The collagen spinning solution was harvested;

[0063] Among them, in order to facilitate the rapid and uniform dispersion of carrageenan in the collagen spinning solution, the carrageenan needs to be soaked and dissolved in water before adding. The amount of water in the collagen spinning solution is calculated according to the weight ratio of the complex to water, and the amount of water carried by the decalcified collagen solution itself is subtracted to calculate the remaining amount of water to be replenished. The carrageenan is soaked in the remaining water to be replenished, and the temperature is raised to 80°C until the carrageenan is completely dissolved. After the temperature drops to room temperature, it is added to the corresponding amount of decalcified collagen solution.

[0064] 2. Preparation of collagen fibers

[0065] The method for preparing collagen fibers in this embodiment comprises the following steps:

[0066] (1) Spinning:

[0067] The collagen spinning stock solution is passed through a wet spinning metering pump with an inlet pressure of 0.1 MPa and an outlet pressure of 1 MPa, a candle-shaped filter, a gooseneck tube, and a spinneret with a spinneret hole diameter of 0.1 mm into a coagulation bath with a pH of 5.9, and coagulation and spinning are performed at 20 m / min to form nascent fibers. The nascent fibers are negatively drafted in the coagulation bath at a spinning speed: bath speed of 1:0.7; wherein the coagulation bath comprises the following substances in weight percentages: 3.5% calcium chloride, 1% sulfuric acid, and the remainder water; the settings and parameters of the wet spinning metering pump, candle-shaped filter, gooseneck tube, and spinneret are all routinely adjusted by those skilled in the art according to actual production conditions, for example, the inlet pressure of the wet spinning metering pump is 0.08-0.11 MPa, and the outlet pressure is 0.9-1.3 MPa; the spinneret hole diameter is 0.05-0.12 mm, and the channel length is 0.1-0.25 mm, which will not be repeated here;

[0068] (2) Post-processing:

[0069] The spun fibers are then subjected to post-processing such as wet stretching, dry stretching, and heat setting to obtain collagen fibers. Similarly, wet stretching, dry stretching, and heat setting are all routinely adjusted by those skilled in the art according to actual production conditions and will not be described in detail here.

[0070] Examples 2-9

[0071] Examples 2-9 were based on the method of Example 1, with adjustments made to the type, concentration, and amount of alkali solution. The specific adjustments are shown in Table 1 below. The alkali solution in Example 9 was a mixture of NaOH and KOH, with both alkalis having a concentration of 10 wt % and the amounts used being 2.5 kg and 2.5 kg.

[0072] Table 1 is a table of alkali solution parameters of Examples 1-9 and Comparative Examples 1-2.

[0073] Types of alkali Concentration / wt% Dosage / kg Example 1 NaOH 2 3.5 Example 2 NaOH 5 4 Example 3 NaOH 8 4 Example 4 NaOH 10 5 Example 5 NaOH 12.5 4 Example 6 NaOH 12 7 Example 7 NaOH 15 7 Example 8 KOH 10 5 Example 9 KOH+NaOH(1:1) 10 5 Comparative Example 4 NaOH 1.25 40 Comparative Example 5 NaOH 20 2.5

[0074] Examples 10-12

[0075] In Examples 10-12, based on the method of Example 4, the pH value of the decalcified collagen solution in the decalcification step was adjusted. The specific adjustment details are shown in Table 2 below.

[0076] Table 2 pH adjustment table of decalcified collagen solutions of Examples 4, 10-12 and Comparative Examples 3-4.

[0077] pH Example 4 6.0 Example 10 5.5 Example 11 7.0 Example 12 8.0 Comparative Example 6 5.0 Comparative Example 7 9.0

[0078] Example 13

[0079] This embodiment uses pigskin as the glue raw material based on the method of embodiment 4.

[0080] Example 14

[0081] This embodiment is based on the method of embodiment 4. In the dissolving step, the dissolving temperature of the glue raw material is controlled at 25°C.

[0082] Examples 15-16

[0083] Examples 15-16 are based on the method of Example 4, except that the water content of the precipitate is controlled during the precipitation step. The water content of the precipitate harvested in Example 15 is 25 wt %, and the water content of the precipitate harvested in Example 16 is 35 wt %.

[0084] Example 17

[0085] This embodiment is based on the method of embodiment 4. In the decalcification step, hydrochloric acid is used to dissolve the precipitate and the pH value is adjusted. If excessive acid is added, sodium hydroxide is used to adjust the pH to 6.0.

[0086] Examples 18-27

[0087] In Examples 18-27, based on the method of Example 4, the weight ratio of collagen to carrageenan and the weight ratio of the complex to water were adjusted. The specific adjustments are shown in Table 3 below.

[0088] Table 3 Adjustment table of the weight ratios of the components in Examples 4 and 18-27.

[0089]

[0090]

[0091] Comparative Example

[0092] Comparative Example 1

[0093] The collagen spinning solution of this comparative example is the supernatant of the crude collagen solution harvested in the dissolution step of Example 4;

[0094] Among them, the collagen spinning solution of this comparative example cannot be made into collagen fibers. This shows that the collagen solution obtained by directly dissolving with alkali solution is difficult to be directly used for preparing fibers.

[0095] Comparative Example 2

[0096] The collagen spinning solution of this comparative example is the decalcified collagen solution harvested in the decalcification step of Example 4;

[0097] The collagen spinning solution of this comparative example is also difficult to be made into collagen fibers. Therefore, it can be seen that the complexation step of this application is a key step in collagen spinning and cannot be deleted at will.

[0098] Comparative Example 3

[0099] The preparation method of the collagen spinning solution of this comparative example comprises the following steps:

[0100] (1) Dissolution:

[0101] 1 kg of cowhide was soaked in 5 kg of 10 wt% NaOH solution at 20°C for 3 hours to fully dissolve the collagen in the cowhide, and crude collagen solution was obtained.

[0102] (2) Complexation:

[0103] The crude collagen solution was allowed to stand until stratification, the supernatant was taken and the pH value was adjusted to 6.0 with citric acid, a small amount of the collected supernatant was freeze-dried into a powder, the actual collagen content in the decalcified collagen solution was calculated, and carrageenan was added to the remaining decalcified collagen solution for complexation reaction. Carrageenan was added at a weight ratio of collagen to carrageenan of 10:90 (the addition method was the same as in Example 4), and the mixture was stirred at a stirring speed of 10-20 rpm for 4 h to ensure thorough mixing and then allowed to stand for defoaming to harvest the collagen spinning solution.

[0104] The collagen spinning solution in this comparative example has too much water content and is difficult to spin into collagen fibers. 2+ Cross-linking precipitation and then using acid and calcium to restore the water solubility of collagen is one of the key steps in achieving collagen spinning.

[0105] Comparative Examples 4-5

[0106] Comparative Example 4-5 Based on the method of Example 4, the type, concentration and amount of alkali solution were adjusted. The specific adjustments are shown in Table 1 above;

[0107] Among them, in Comparative Example 4, the amount of alkali solution used is too much, and the collagen content per unit volume of the corresponding crude collagen solution is too low. According to the method of Example 4, the precipitate is difficult to be effectively collected in the precipitation step, and thus it is difficult to harvest the desired collagen spinning solution.

[0108] Comparative Examples 6-7

[0109] Comparative Examples 6-7 are based on the method of Example 4, except that the pH value of the decalcified collagen solution in the decalcification step is adjusted. For specific adjustment details, see Table 2 above.

[0110] Performance testing

[0111] The collagen spinning solutions of Examples 1-27 and Comparative Examples 3-7 were used as solution samples, and the collagen fibers obtained from the solution samples were used as fiber samples to perform the following performance tests. The test contents and standards are shown in Table 4 below.

[0112] Stock solution sample: weigh the weight of the raw material as m0; harvest the precipitate of the crude collagen solution, add pure water to wash twice, and then dry the water, weigh it as m1, and calculate the utilization rate of the raw material as m2 = ((m0-m1)

[0113] / m0)*100%.

[0114] Fiber samples: Specifications are 1.33 dtex*38 mm. For each fiber sample, first visually inspect the fiber appearance. Then, quantitatively weigh 10 g of the sample and add 10 g of 25°C purified water to the fiber sample to observe the fiber's water absorption and gel properties. The pH value of the fiber aqueous solution is measured with a pH meter, and the moisture content (%) of the fiber is measured with a moisture meter. Finally, the whiteness (%) and dry breaking strength (cN / dtex) of the sample are tested according to the methods described in GB / T 14463-2008, "Viscose Staple Fibers."

[0115] The fibers of Examples 1-4, 8-27, and Comparative Examples 6-7 all had a white appearance, free of black spots, dirt, and other impurities. The fibers of Examples 5-7 all had an off-white appearance, free of black spots, dirt, and other impurities. The fibers of Comparative Example 5 had a yellow appearance, with black spots, dirt, and other impurities. This indicates that the collagen fibers of Examples 1-27 and Comparative Examples 6-7 meet the fiber appearance standards, while the collagen fibers of Comparative Example 5 do not. This may be due to the excessively high alkali concentration in the alkali solution, which denatures the collagen, causing it to turn yellow or even black.

[0116] In addition, the water absorption of the collagen fibers of Examples 1-20, 23-27 and Comparative Examples 5-7 of the present application is "1s water absorption, transparent", and the water absorption of the collagen fibers of Example 1-20 is "2s water absorption, transparent", which shows that the collagen proteins of the present application have good water absorption. Except for Comparative Example 5, the gel state of the above Examples 1-27 and Comparative Examples 6-7 is "slightly smooth and soft, and completely soluble in water at room temperature". It can be seen that excessively high concentrations of alkali solution will affect the gel state effect of the collagen fibers. The preparation method of the present application requires strict control of the concentration and amount of alkali solution.

[0117] Other test results are shown in Table 5.

[0118] Table 4 is the test result table of Examples 1-27 and Comparative Examples 3-7.

[0119]

[0120] Table 5 is the test result table of Examples 1-27 and Comparative Examples 3-7.

[0121]

[0122] Referring to Table 5, the test results of Examples 1-9 are compared with those of Comparative Examples 4-5. The test results of Examples 1-9 meet the test standards in Table 4. In contrast, Comparative Example 4 failed to produce a collagen spinning solution. While Comparative Example 5 achieved a high recovery rate of the collagen raw material, its fiber appearance, gel-state properties, pH value, whiteness, and dry breaking strength did not meet the standard requirements.

[0123] It can be seen that the present application uses a set amount of alkali solution to effectively dissolve the collagen in the rubber raw material. However, if the alkali solution concentration used is too low, the collagen content per unit volume of the crude collagen solution will be low, and thus the collagen spinning solution cannot be obtained; if the alkali solution concentration is too high, it will affect the fiber strength of the collagen fibers corresponding to the collagen spinning solution (reflected by dry breaking strength, the greater the dry breaking strength, the stronger the fiber strength). The present application preferably uses an alkali solution with a concentration of 2-15wt%, specifically controlling the weight ratio of the rubber raw material to the alkali solution to be 1:3.5-7. Among them, Example 4 is a preferred embodiment among Examples 1-9.

[0124] Comparing the test results of Example 4 with those of Examples 10-12 and Comparative Examples 6-7, the pH value in the decalcification step will affect the water absorption and fiber strength of the collagen fibers to a certain extent. For this reason, this application limits the pH value to 5.5-8.0.

[0125] The test results of Example 13 show that the method of the present application is not limited to using cowhide as the rubber raw material, and can also be used to prepare collagen spinning solution as long as the rubber raw material contains sufficient amount of collagen.

[0126] Comparing the test results of Example 4 with those of Examples 15-16, it can be concluded that excessive water content in the precipitate will affect the effect of restoring the water solubility of collagen to a certain extent, so it is appropriate to control the water content in the precipitate to 30wt%.

[0127] Comparing the test results of Example 4 with those of Example 17, it can be found that the acidification using citric acid in this application has better water solubility and fiber strength than hydrochloric acid, so it is further preferred.

[0128] Comparing the test results of Example 4 with those of Examples 18-27, it can be seen that in the complexation step of the present application, excessive addition of carrageenan will limit the water absorption of the collagen fibers to a certain extent, but if too little carrageenan is added, the fiber strength of the harvested collagen fibers is poor. In addition, excessive or insufficient content of the complex will affect the fiber strength. For this reason, the present application preferably has a weight ratio of collagen to carrageenan of 10-36:64-90, and a weight ratio of the complex to water of 16-33:84-77. Further preferred is Example 25, in which the weight ratio of collagen to carrageenan is 25:75, and the weight ratio of the complex to water is 25:75.

[0129] Application Examples

[0130] This application takes the collagen fibers produced in Example 25 as an example, which can be well applied in the following fields including but not limited to:

[0131] 1. Applied in non-woven fields: such as facial masks, sanitary napkins, diapers, underarm patches, etc.

[0132] 2. Application in the textile field: such as underwear, socks, shorts, clothing fabrics and bedding, etc. Collagen fiber is more suitable for spinning and producing protein fibers than general plant proteins, and has excellent moisturizing properties, good affinity with human skin, and is comfortable to wear. It is suitable for the development of bedding, shirts, knitted underwear, socks and other products;

[0133] 3. Applied in the medical field: such as Band-Aids, bandages, dressings, etc., with good anti-seepage effect and healing function;

[0134] 4. Applied in the food field: For example, preservatives in the food field, fruit fresh-keeping bags, etc. can also be used in artificial leather;

[0135] 5. Application in papermaking industry: mainly in the form of fiber and plant fiber to form composite products, used to improve paper strength, water absorption, air permeability, tightness and whiteness;

[0136] 6. Applied in the fields of composite materials and nanomaterials.

[0137] It should be noted that when the collagen fibers of the present application are applied to the above-mentioned fields, their weaving methods are the same as those of materials well known to those skilled in the art, such as polyester fibers.

[0138] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing a collagen spinning solution, characterized in that: The following steps are involved: Dissolution: Soak the raw material of the collagen in an alkaline solution with a concentration of 2-15 wt %, with the weight ratio of the raw material of the collagen to the alkaline solution being 1:3.5-7, and harvest the crude collagen solution after it is fully dissolved; Precipitation: Let the crude collagen solution stand until layers are separated, take the supernatant and add calcium chloride solution to harvest the precipitate; Decalcification: Add acid to the precipitate until the precipitate is fully dissolved, and adjust the pH value to 5.5-8 to obtain decalcified collagen solution; Complexation: Take decalcified collagen solution, add carrageenan, stir evenly and let it stand to defoam, and then harvest the collagen spinning solution.

2. The preparation method according to claim 1, wherein: The glue raw material is derived from one or more of animal bones, tendons, ligaments, fascia and skin.

3. The preparation method according to claim 2, wherein: The rubber raw material is derived from cowhide.

4. The preparation method according to claim 1, wherein: In the dissolving step, the dissolving temperature of the glue raw material is controlled to be ≤20°C.

5. The preparation method according to claim 1, wherein: The alkali solution is one or both of sodium hydroxide and potassium hydroxide.

6. The preparation method according to claim 1, wherein: In the precipitation step, a calcium chloride solution with a concentration of 30±5wt% is slowly added to the supernatant of the crude collagen solution while stirring until flocculent solids stop being produced. The solution is allowed to stand until stratification, the supernatant is discarded, and the harvested flocculent solids are washed with pure water to obtain the precipitate with a water content of ≤30wt%.

7. The preparation method according to claim 1, wherein: The acid is one or more of sulfuric acid, hydrochloric acid, nitric acid, citric acid, acetic acid and tartaric acid.

8. The preparation method according to claim 1, wherein: In the decalcification step, the pH value is adjusted with citric acid or sodium hydroxide.

9. The preparation method according to claim 1, wherein: In the complexing step, the carrageenan is added at a weight ratio of collagen to carrageenan of 10-36:64-90.

10. The preparation method according to claim 1, characterized in that: The decalcified collagen solution in the collagen spinning solution forms a complex with carrageenan, and the weight ratio of the complex to water is 16-33:84-77.

11. A collagen spinning solution, characterized in that: The method is as described in any one of claims 1 to 10.

12. A collagen fiber, characterized in that: It is made from the collagen spinning solution as claimed in claim 11.

13. Use of the collagen fiber according to claim 12.

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