A kind of degumming method of apocynum venetum

Abstract

The present invention relates to a method for degumming apocynum venetum, and belongs to the technical field of apocynum venetum degumming processes. The apocynum venetum degumming method provided by the present invention comprises a combined degumming process of pre-acid treatment, pre-alkali treatment and mild oxidase treatment. The present invention is based on composite enzyme degumming, combined with a mild oxidation treatment method, which can effectively remove major impurities such as pectin, lignin, hemicellulose, and other impurities on apocynum venetum fibers, as well as other impurities such as natural pigments, and can increase the whiteness of apocynum venetum fibers, improve water absorption and hair effect, make the surface of the fabric smooth, and feel soft and smooth; at the same time, the hydrophilicity and water absorption diffusion of the fabric are significantly increased, and the mechanical properties are improved, which can correspondingly improve the coloring rate and levelness of the dyeing process.

Description

Technical Field

[0001] The invention belongs to the technical field of apocynum venetum degumming process, and particularly relates to a apocynum venetum degumming method. Background Art

[0002] Apocynum venetum, a perennial wild herbaceous bast fiber plant in the Apocynaceae family, is a unique botanical resource in my country. Its bast fibers, located within the bast tissue of the plant's stem, are long, slender fibers arranged in very loose bundles. They possess the luster of silk, the crispness of linen, the malleability of velvet, and the softness of cotton. Textiles made from them are breathable and highly absorbent, while also being soft, antibacterial, and cool in summer and warm in winter. Therefore, apocynum venetum is known as the "king of wild fibers." However, compared to flax or ramie, its cellulose content is relatively low, at only 45%-55%. Its bast tissue has a thicker gelatinous layer, resulting in a dense fiber bundle structure, high hydrophobicity, and low accessibility. Furthermore, the high pectin content in the bast tissue results in a strong adhesion between the wood and epidermal fibers. Therefore, before being used as textile fiber, Apocynum venetum must be degummed and degumming is difficult. Correspondingly, the degumming process will have a more direct impact on the fiber properties, which has become an important reason restricting Apocynum venetum products from entering the market.

[0003] Currently, there are three methods for degumming apocynum venetum: chemical degumming, physical degumming, and biological degumming. Chemical degumming is a relatively mature process. Traditional chemical degumming primarily relies on alkali degumming, which uses large amounts of strong acids and alkalis, causing environmental pollution and fiber damage. Degumming apocynum venetum fiber is more difficult than other hemp fibers, primarily due to its high concentration of pectin. Using the traditional secondary pre-alkali degumming method inevitably increases the use of chemicals, leading to even greater environmental damage and contradicting the principles of green and sustainable development. Physical degumming primarily involves high temperature and high pressure, ultrasound, and microwave degumming. While physical degumming is less polluting, its degumming efficiency is low. Biological degumming is environmentally friendly, but suffers from low degumming efficiency and inconsistent quality of the resulting dried hemp. Biological degumming is divided into two types: microbial degumming and enzymatic degumming. In microbial degumming, the availability of microorganisms suitable for apocynum venetum degumming is limited, requiring further research. Enzymatic degumming utilizes enzymes to react with pectin in apocynum venetum, thereby degrading the pectin. Compared with chemical degumming, enzyme degumming has higher requirements on degumming conditions and limited degumming rate, and its residual rubber content is higher than that of chemical degumming.

[0004] The biological-chemical combined degumming method can achieve a relatively ideal degumming effect and obtain a good quality of refined hemp under the premise of alleviating environmental pollution. However, the current reports on the biological-chemical combined degumming of Apocynum venetum are relatively limited, and the existing degumming enzymes have a single effect, are expensive, and have a high cost. In addition, the colloid component structure is complex, and the added degumming enzymes have a single performance. There are problems such as high requirements for degumming conditions, low degumming efficiency, low fiber whiteness, and unstable quality of refined hemp. Therefore, developing a gentle degumming method that can reduce Apocynum venetum damage, improve Apocynum venetum whiteness, and reduce wastewater viscosity is a technical problem that is currently in urgent need of solution. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide a method for degumming apocynum venetum with high degumming efficiency, good whiteness and low damage.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for degumming apocynum venetum, comprising the following steps:

[0008] (1) adding apocynum venetum to an acid solution, heating at 55° C.-65° C. for 55 min-75 min, and then washing; the bath ratio of the apocynum venetum to the acid solution is 1:(20-50);

[0009] (2) adding alkali solution to the Apocynum venetum cleaned in step (1), heating at 65° C.-70° C. for 95 min-105 min, and then cleaning; the bath ratio of the Apocynum venetum to the alkali solution is 1:(20-50);

[0010] (3) adding a mixed solution containing a complex enzyme and an oxidant to the apocynum venetum cleaned in step (2), heating the mixture at 70° C.-80° C. for 45 min-85 min, and then washing the mixture, and drying the mixture to obtain apocynum venetum refined fiber; the bath ratio of the apocynum venetum to the mixed solution is 1:(20-50).

[0011] The degumming method of the present invention adopts a composite enzyme and a mild oxidation chemical method to combine degumming. Compared with the existing alkaline oxygen process, it can reduce the strong damage to the apocynum venetum, reduce the viscosity of sewage and the burden of sewage treatment. The present invention uses pre-acid treatment and pre-alkali treatment to preliminarily degrade the colloid components of the outer layer of the fiber that are not directly connected to the fiber or have a loose structure. Under the condition of not damaging the fiber structure, the composite enzyme is used in combination with an oxidant to treat the non-fibrous colloid in one step to achieve the purpose of complete degumming. The degumming method of the present invention has a good degumming effect on the apocynum venetum, can significantly reduce the glue content of the fiber, increase the whiteness of the fiber, reduce the strong damage to the fiber, etc., and the process is green and environmentally friendly.

[0012] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in step (1), the acid in the acid solution is sulfuric acid, and the mass of the sulfuric acid is 1.25%-2% of the mass of the apocynum venetum; the heating temperature is 60°C-65°C, and the heating time is 55 minutes-60 minutes. Pre-acid treatment under these sulfuric acid concentrations and heating conditions can effectively improve the whiteness of the apocynum venetum after degumming and impart better mechanical strength to the apocynum venetum.

[0013] As a preferred embodiment of the method for degumming apocynum venetum of the present invention, in step (1), the mass of the sulfuric acid is 1.75%-2% of the mass of the apocynum venetum. When the sulfuric acid concentration is 1.75%-2% of the mass of the apocynum venetum, the apocynum venetum after pre-acid treatment has good whiteness and mechanical properties.

[0014] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in step (2), the alkali solution comprises the following components in weight percentages based on the mass of the apocynum venetum: 4.5%-6.5% sodium hydroxide, 4%-5% sodium silicate, 2.5%-4.5% sodium sulfite, and 3%-3.5% penetrant. The present invention uses a combination of sodium hydroxide, sodium silicate, sodium sulfite, and penetrant as an alkali agent to pre-alkaline-treat the apocynum venetum, thereby preliminarily degrading the colloid on the apocynum venetum surface. The degumming is combined with pre-acid treatment and enzyme mild oxidation treatment to improve the whiteness of the dried apocynum venetum.

[0015] Preferably, the penetrant is an anionic alkali-resistant penetrant. The use of an anionic alkali-resistant penetrant can better promote the effect of the alkali solution and achieve a better pre-alkali treatment effect.

[0016] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in the step (2), the heating time is 100 min-105 min.

[0017] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in step (3), the compound enzyme comprises pectinase, hemicellulase, ligninase, laccase and xylanase. The compound enzyme obtained by combining the above multiple enzymes has a better degumming effect.

[0018] As a preferred embodiment of the apocynum venetum degumming method of the present invention, the complex enzyme comprises the following components by mass: 60-64 parts of pectinase, 17-19 parts of hemicellulase, 10-13 parts of ligninase, 3-5 parts of laccase and 4-5 parts of xylanase.

[0019] Preferably, the activities of the pectinase, hemicellulase, laccase and xylanase are ≥800 U / mL; and the activity of the ligninase is ≥300 U / mL.

[0020] The invention adopts a composite enzyme containing multiple biological enzymes in combination with an oxidant to perform enzymatic degumming under oxidative conditions, which can effectively remove the colloid on the surface of Apocynum venetum, has a high degumming rate and little colloid residue.

[0021] Preferably, the complex enzyme comprises the following components by mass: 60 parts of pectinase, 17 parts of hemicellulase, 13 parts of ligninase, 5 parts of laccase and 5 parts of xylanase.

[0022] The composite enzyme has a better degumming effect than other enzymes, can significantly improve the whiteness of the degummed apocynum venetum, and has better fiber strength after degumming.

[0023] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in step (3), the concentration of the complex enzyme in the mixed solution is 15 g / L-25 g / L. The enzyme concentration affects the degumming efficiency and degumming effect. Through research, it was found that at this concentration of complex enzyme, the surface colloid of apocynum venetum can be effectively removed, the whiteness of the dried apocynum venetum can be improved, and the damage to the apocynum venetum fiber can be reduced.

[0024] As a preferred embodiment of the apocynum venetum degumming method of the present invention, in step (3), the oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide in the mixed solution is 4g / L-6g / L. The present invention uses hydrogen peroxide to provide a mild oxidizing environment, and degumming is combined with a composite enzyme, thereby requiring low degumming conditions, achieving high degumming efficiency, and producing a refined apocynum venetum with stable quality.

[0025] As a preferred embodiment of the method for degumming apocynum venetum of the present invention, in step (3), the washing is first performed with hot water and then with cold water. The present invention uses alternating hot and cold water to wash the degummed apocynum venetum, which can fully clean the surface colloid residue and better maintain the strength of the apocynum venetum.

[0026] Preferably, the temperature of the hot water is 55°C-65°C, and the temperature of the cold water is 0°C-15°C.

[0027] The present invention has the following beneficial effects:

[0028] (1) The degumming method of the present invention combines chemical degumming and biological degumming, and combines composite enzymes with oxidative environment for degumming, which causes less damage to the fiber. It can replace the input of multiple auxiliary agents in the traditional degumming process of Apocynum venetum, reduce the types and amounts of raw materials, simplify the degumming process and operation, and effectively improve the degumming and impurity removal efficiency of Apocynum venetum. Compared with the existing biological enzyme method, the residual glue rate of Apocynum venetum is about 5%, and the weight loss rate reaches 40%. At the same time, the viscosity of the sewage is low, and the washing burden is light. (2) The degumming method of the present invention is based on composite enzymes, combined with mild oxidation and chemical treatment methods, which can effectively remove natural glue impurities, other various impurities, natural pigments, etc. on Apocynum venetum fabrics, and can increase whiteness, improve hair effect, make the fabric surface smooth, and feel soft and smooth; at the same time, the hydrophilicity and water absorption diffusion of the fabric are significantly increased, which can correspondingly improve the coloring rate and levelness of the dyeing process. The degumming process and operation are simple, and the damage to Apocynum venetum is small. The single yarn strength of apocynum venetum reaches 8cn, with an average breaking strength of 4.5cN / dtex, meeting spinning requirements. Furthermore, the degumming method of the present invention is a novel degumming process that combines bio-enzymes with mild oxidation, expanding the adaptability of bio-mild oxidation degumming processes. Degumming performance is not affected by differences in apocynum venetum production environment, bark condition, or peeling method. The degumming method of the present invention is applicable to products degummed after pilot testing, resulting in stable performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 To study the effect of adding hydrogen peroxide on the weight loss rate of Apocynum venetum;

[0030] Figure 2 To investigate the effect of adding hydrogen peroxide for oxidation on the whiteness of Apocynum venetum;

[0031] Figure 3 To study the effect of adding hydrogen peroxide for oxidation on the strength of Apocynum venetum single fiber;

[0032] Figure 4 The effect of different enzyme treatment temperatures on the weight loss rate of Apocynum venetum;

[0033] Figure 5 The effect of different enzyme treatment temperatures on the whiteness of Apocynum venetum;

[0034] Figure 6 The effect of different enzyme treatment temperatures on the strength of Apocynum venetum single fiber;

[0035] Figure 7 The test results of whiteness strength, elongation and breaking strength of Apocynum venetum under different pre-acid treatment conditions are shown;

[0036] Figure 8 The results of the whiteness strength, elongation and breaking strength test of Apocynum venetum under different pre-alkali treatment conditions are shown in the figure.

[0037] Figure 9 The test results of whiteness strength, elongation and breaking strength of Apocynum venetum under different degumming agent treatment conditions are shown;

[0038] Figure 10 These are scanning electron microscope images of the apocynum venetum fiber before and after degumming in Example 3, wherein (a) shows the apocynum venetum fiber before degumming, and (b) shows the apocynum venetum fiber after degumming.

[0039] Figure 11 This is the infrared spectrum of Apocynum venetum before and after degumming in Example 3. DETAILED DESCRIPTION

[0040] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0042] Example 1

[0043] 1.1 Selection of enzymes in apocynum venetum degumming agent

[0044] The degumming effect of different enzymes was studied by combining the composite enzyme and hydrogen peroxide mild oxidation in step (3) on the bast of Apocynum venetum. The weight loss rate, whiteness and single fiber strength were used as evaluation indicators to analyze and discuss the degumming effect of different enzymes. Four different bioenzymes were used to explore the degumming effect of the degummed bast after degumming. The oxidation conditions were 10g / L enzyme, 2g / L hydrogen peroxide, bath ratio 1:50, 85℃, 30min. The results are shown in Table 1. Among them, the enzymes JS-369, HS-535, ZW-616 and YA-460 are all composite enzymes. The composite enzyme JS-369 includes the following components by mass: 60 parts of pectinase, 17 parts of hemicellulase, 13 parts of ligninase, 5 parts of laccase and 5 parts of xylanase. The composite enzyme HS-535 includes the following components by mass: 65 parts of pectinase, 20 parts of hemicellulase, 8 parts of ligninase, 2 parts of laccase and 5 parts of xylanase. The compound enzyme ZW-616 comprises the following components by weight: 70-80 parts of pectinase, 10-15 parts of hemicellulase, and 10-15 parts of ligninase. The compound enzyme YA-460 comprises the following components by weight: 70 parts of pectinase, 25 parts of hemicellulase, and 5 parts of ligninase.

[0045] This embodiment and the following whiteness test are all based on GB5881-86 "Test method for whiteness of ramie fibers", the strength and breaking strength tests are based on GB5881-86 "Test method for breaking strength of ramie single fibers", and the length test is based on GB5881-86 "Test method for length of ramie fibers".

[0046] Table 1 Comparison of properties of refined hemp after degumming with different compound enzymes

[0047]

[0048]

[0049] From the weight loss test results in Table 1, it can be seen that the weight loss rate of the apocynum venetum fiber obtained by degumming with the biological enzyme HS-535 is the largest, and the weight loss rate of the apocynum venetum fiber treated with the biological enzyme YA-460 is the smallest; from the whiteness test results, it can be seen that the whiteness of the apocynum venetum bast is the best when treated with the composite biological enzyme JS-369, and the whiteness of the dried hemp prepared by the biological enzyme YA-460 is the worst; from the single fiber strength test results, it can be seen that the single fiber strength of the apocynum venetum obtained by degumming with the biological enzyme HS-535 is the largest, followed by the biological enzyme ZW-616, and the dried hemp obtained by degumming with the biological enzyme JS-369 has the smallest strength.

[0050] Comprehensive comparison shows that under oxidative conditions (10 g / L enzyme, 2 g / L hydrogen peroxide, bath ratio 1:50, 85°C, 30 min), the biological enzyme JS-369 has the highest whiteness, the largest weight loss rate, and the best degumming effect; followed by the composite biological enzyme HS-535. The dried hemp obtained using the composite biological enzyme YA-460 has the lowest weight loss rate and whiteness, and the worst degumming effect.

[0051] 1.2 Selection of conditions for step (3) in the degumming method

[0052] The effects of oxidation conditions and temperature on degumming were investigated by measuring the effects of the addition of hydrogen peroxide and the different enzyme treatment temperatures on weight loss rate, whiteness and strength. Figure 1 To investigate the effect of adding hydrogen peroxide on the weight loss rate of Apocynum venetum. Figure 2 To investigate the effect of adding hydrogen peroxide for oxidation on the whiteness of Apocynum venetum. Figure 3 The effect of adding hydrogen peroxide for oxidation on the strength of Apocynum venetum single fiber was investigated. Figure 1-3 It can be seen that the introduction of oxidation conditions can increase the weight loss rate of Apocynum venetum and significantly improve its whiteness. The whiteness of the dried Apocynum venetum obtained by degumming with bio-enzyme JS-369 and bio-enzyme HS-535 is more than twice that of the non-oxidative conditions. Figure 4 The effect of different enzyme treatment temperatures on the weight loss rate of Apocynum venetum. Figure 5 The effect of different enzyme treatment temperatures on the whiteness of Apocynum venetum. Figure 6The effect of different enzyme treatment temperatures on the strength of Apocynum venetum single fiber is shown in Figure 2. Figure 4-Figure 6 It can be seen that the higher the enzyme treatment temperature, the higher the whiteness and weight loss rate of the dry apocynum venetum, but there is a certain damage to the strength of the single apocynum venetum fiber after degumming.

[0053] Through the exploration of this example, an enzyme-oxidation method combining biological enzymes with hydrogen peroxide was selected to degumming Apocynum venetum.

[0054] Example 2

[0055] 2.1 Step (1) Investigation of pre-acid treatment conditions

[0056] The weighed Apocynum venetum was placed in a beaker, 98% sulfuric acid solution was added, and the mixture was placed in a water bath for heating treatment. The sulfuric acid concentration in the pre-acidification conditions (1.25%, 1.75%, 2.25%), water bath temperature (55°C, 65°C, 75°C), and heating time (55min, 65min, 75min) were subjected to factor analysis. A total of 9 groups of orthogonal experiments were conducted on the pre-acidification treatment. The orthogonal experimental scheme is shown in Table 2.

[0057] Table 2 Orthogonal experimental scheme for pre-acid treatment

[0058] serial number Sulfuric acid concentration (to fabric weight) Temperature / ℃ Time / min A1 1.25％ 55 55 A2 1.75％ 65 55 A3 2.25％ 75 55 A4 1.25％ 75 65 A5 1.75％ 55 65 A6 2.25％ 65 65 A7 1.25％ 65 75 A8 1.75％ 75 75 A9 2.25％ 55 75

[0059] The effects of sulfuric acid concentration, pre-acid treatment temperature and time on the properties of Apocynum venetum were determined by 9 groups of orthogonal experiments. The whiteness, strength, elongation and strength of Apocynum venetum treated in step (1) were tested. The test results are as follows: Figure 7 As shown, Figure 7 The left picture shows the whiteness test results of Apocynum venetum under different pre-acid treatment conditions. Figure 7 As can be seen from the left figure, the lowest whiteness of the pre-acidified apocynum venetum fiber is 68.38% and the highest whiteness is 76.36%. From the whiteness test results, 5 groups of apocynum venetum with the best whiteness were selected to test their strength, elongation and breaking strength. The test results are as follows Figure 7 As shown in the figure on the right, after pre-acid treatment, the minimum average strength was 8.6 cN, the maximum average strength was 13 cN, the minimum elongation was 0.23 mm, the maximum elongation was 0.45 mm, the minimum breaking strength was 4.29 cN / dtex, and the maximum breaking strength was 6.53 cN / dtex. Degumming in groups A1 and A2 showed superior mechanical strength and whiteness, with A2 achieving the best results. The pre-acidification conditions were: 1.75% sulfuric acid solution per fabric weight, 65°C, and 55 minutes.

[0060] 2.2 Step (2) Study on pre-alkali treatment conditions

[0061] The pre-acid-treated apocynum venetum was washed with clean water, and sodium hydroxide, sodium silicate, sodium sulfite, and an anionic alkali-resistant penetrant were added in sequence. The plants were then placed in a waterbath and heated for alkali boiling. Alkali boiling was used as the single variable, and pre-acidification and enzyme treatment were used as quantitative factors. Factor analysis was performed on the alkali boiling conditions, including sodium hydroxide concentration (4.5%, 5.5%, 6.5%), sodium silicate concentration (3%, 4%, 5%), sodium sulfite concentration (2.5%, 3.5%, 4.5%), anionic alkali-resistant penetrant concentration (1.5%, 2.5%, 3.5%), heating temperature (50°C, 60°C, 70°C), and heating time (85 min, 95 min, 105 min). Eighteen orthogonal experimental groups were obtained. The orthogonal experimental scheme is shown in Table 3.

[0062] Table 3 Orthogonal experimental scheme for pre-alkali treatment

[0063]

[0064] The effects of the content of each component in the alkali solution, the temperature and time of the pre-alkali treatment on the properties of Apocynum venetum in step (2) were determined by 18 groups of orthogonal experiments. The whiteness, strength, elongation and strength of each group of Apocynum venetum after treatment were tested. The test results are as follows: Figure 8 As shown, Figure 8 The left picture shows the whiteness test results of Apocynum venetum under different pre-alkali treatment conditions. Figure 8 As can be seen from the left figure, the lowest whiteness of the apocynum venetum fiber after pre-alkali is 66.2% and the highest whiteness is 75.9%. From the whiteness test results, 10 groups of apocynum venetum with the best whiteness were selected to test their strength, elongation and breaking strength. The test results are as follows Figure 8 As shown in the figure on the right, after pre-alkali treatment, the lowest average strength was 6.1 cN, the highest average strength was 10.46 cN, the minimum elongation was 0.18 mm, the maximum elongation was 0.44 mm, the minimum breaking strength was 3.04 cN / dtex, and the maximum breaking strength was 5.23 cN / dtex. Among them, the mechanical strength and whiteness of apocynum venetum after degumming in groups B3 and B18 were superior, with B3 having the best degumming effect among apocynum venetum. The pre-alkali treatment conditions were: 4.5% sodium hydroxide, 4% sodium silicate, 2.5% sodium sulfite, 3.5% penetrant, temperature 70°C, and time 105 minutes.

[0065] 2.3 Step (3) Investigation of enzyme combined with mild oxidation treatment conditions

[0066] After pre-acid and pre-alkali treatment, Apocynum venetum was washed clean with warm water and placed in a beaker. The enzyme complex JS-369 was added, and the pH was controlled between 9 and 11. Hydrogen peroxide was then added, and the pH of the solution was measured to maintain a pH between 9 and 11. Finally, the solution was heated for enzymatic treatment, washed with warm water, then washed with cold water, and dried to obtain the refined Apocynum venetum. Within this pH range, the enzyme combined with mild oxidation treatment was optimal. Using pre-acid treatment and alkali boiling as quantitative variables and enzyme treatment as the single variable, a factor analysis was performed on the enzyme complex JS-369 concentrations (15 g / L, 20 g / L, 25 g / L), hydrogen peroxide concentrations (4 g / L, 6 g / L, 8 g / L), heating temperatures (70°C, 85°C, 100°C), and heating times (45 min, 65 min, 85 min), resulting in nine orthogonal experimental groups. The orthogonal experimental scheme is shown in Table 4.

[0067] Table 4 Orthogonal experimental scheme for enzyme treatment

[0068] serial number Enzyme concentration (g / L) Hydrogen peroxide concentration (g / L) Temperature / ℃ Time / min C1 15 4 70 45 C2 15 6 100 65 C3 15 8 85 85 C4 20 4 100 85 C5 20 6 85 45 C6 20 8 70 65 C7 25 4 85 65 C8 25 6 70 85 C9 25 8 100 45

[0069] The effects of the amount of complex enzyme, amount of hydrogen peroxide, temperature and time on the properties of Apocynum venetum in step (3) were determined by 9 groups of orthogonal experiments. The whiteness, strength, elongation and strength of the treated Apocynum venetum were tested. The test results are as follows: Figure 9 As shown, Figure 9 The left picture shows the results of the whiteness test of Apocynum venetum under different enzyme combined mild oxidation treatment conditions. Figure 9 As can be seen from the left figure, the lowest whiteness of the Apocynum venetum fiber after enzyme combined with mild oxidation treatment is 68.34%, and the highest whiteness is 75.06%. From the whiteness test results, 5 groups of Apocynum venetum with the best whiteness were selected to test their strength, elongation and breaking strength. The test results are as follows Figure 9 As shown in the figure on the right, after enzyme combined with mild oxidation treatment, the lowest average strength was 7.33 cN, the highest average strength was 9.69 cN, the minimum elongation was 0.31 mm, the maximum elongation was 0.45 mm, the minimum breaking strength was 3.16 cN / dtex, and the maximum breaking strength was 4.84 cN / dtex. Among them, the mechanical strength and whiteness of apocynum venetum after degumming in groups C1 and C8 were superior, with C8 achieving the best degumming effect. The degumming agent treatment conditions were: 25 g / L degumming agent, 6 g / L hydrogen peroxide, temperature 70°C, and time 85 minutes.

[0070] Through further research, it was concluded that the pre-acid conditions for the degumming step (1) of Apocynum venetum were: 1.25%-2% sulfuric acid solution on the weight of the fabric, temperature 55°C-65°C, and time 55min-75min; the pre-alkali conditions for the step (2) were: 4.5%-6.5% sodium hydroxide, 4%-5% sodium silicate, 2.5%-4.5% sodium sulfite, 3%-3.5% penetrant on the weight of the fabric, temperature 65°C-70°C, and time 95min-105min; and the enzyme combined mild oxidation treatment conditions for the step (3) were: 15g / L-25g / L complex enzyme JS-369, 4g / L-6g / L hydrogen peroxide, temperature 70°C-80°C, and time 45min-85min.

[0071] Example 3

[0072] This embodiment provides a method for degumming apocynum venetum, comprising the following steps:

[0073] (1) Add Apocynum venetum to sulfuric acid solution at a bath ratio of 1:50, heat at 60°C for 60 minutes, and wash; the amount of sulfuric acid used is 2% owf;

[0074] (2) adding the cleaned Apocynum venetum obtained in step (1) into an alkali solution at a bath ratio of 1:50; heating the solution at 70° C. for 105 minutes and then cleaning the solution; the alkali solution comprises: 4.5% owf sodium hydroxide, 4% owf sodium silicate, 2.5% owf sodium sulfite, and 3.5% owf penetrant;

[0075] (3) adding a mixed solution of bioenzyme JS-369 and hydrogen peroxide to the apocynum venetum cleaned in step (2) at a bath ratio of 1:50; wherein the amount of the apocynum venetum degumming agent is 25 g / L, the mass fraction of the hydrogen peroxide is 30%, the amount of the hydrogen peroxide is 6 g / L, heating at 70° C. for 85 min, first washing with hot water at 55° C. and then washing with cold water at 10° C., and drying at 60° C. to obtain apocynum venetum refined fiber.

[0076] The average whiteness of the apocynum venetum treated by the degumming method of this embodiment reaches 77.34%, the average strength reaches 9.7 cN, the average elongation reaches 0.57 mm, and the average breaking strength reaches 4.91 cN / dtex, indicating that the apocynum venetum treated by the present invention has higher whiteness and mechanical properties.

[0077] Scanning electron microscope was used to observe the surface morphology of Apocynum venetum before and after degumming. Figure 10 As shown in Figure 1, (a) shows the apocynum venetum fiber before degumming. The surface is rough, uneven, and has many impurities. It can be clearly seen that there are a large number of colloid particles wrapped on the surface of the apocynum venetum fiber. Figure 10As shown in (b), the surface is smooth and flat, indicating that the impurities on the surface of the apocynum venetum fiber have been basically removed. The degumming agent and degumming method of the present invention can better remove the colloid on the surface of the apocynum venetum fiber.

[0078] The structure of Apocynum venetum fibers before and after degumming was characterized by infrared spectrometer with a scanning range of 4000-500 cm –1 , resolution 4cm –1 . Figure 11 The infrared spectrum of the apocynum venetum fiber is shown in FIG. 1 , wherein the treated apocynum venetum fiber is the apocynum venetum fiber degummed in this embodiment. Figure 11 It can be seen that at 3369cm –1 The peak at (-OH stretching vibration) is the characteristic absorption peak of cellulose and hemicellulose components, 2898 cm –1 The peak at 1728 cm (C-H stretching vibration) is the characteristic peak of cellulose and macromolecular colloids. –1 and 1643cm –1 The absorption peak at 1427 cm is the characteristic absorption peak of lignin carbonyl and hemicellulose acetyl. –1 、1369cm –1 、1318cm –1 、1157cm –1 The absorption peak at 665cm is the characteristic absorption peak of galacturonic acid in pectin in the fingerprint region. –1 The peak at (C—OH out-of-plane bending) is the main characteristic peak of cellulose. After the degumming treatment of apocynum venetum fiber, the above absorption vibration peaks are weakened to a certain extent, indicating that after the degumming treatment, the pectin and non-cellulose colloids in the apocynum venetum fiber are basically removed.

[0079] Example 4

[0080] A method for degumming apocynum venetum comprises the following steps:

[0081] (1) Add Apocynum venetum to sulfuric acid solution at a bath ratio of 1:50, heat at 65°C for 55 minutes, and wash; the amount of sulfuric acid used is 1.75% owf;

[0082] (2) adding the cleaned Apocynum venetum obtained in step (1) into an alkali solution at a bath ratio of 1:50; heating the solution at 65° C. for 95 minutes and then cleaning the solution; the alkali solution comprises: 6.5% owf sodium hydroxide, 5% owf sodium silicate, 4.5% owf sodium sulfite, and 3.5% owf penetrant;

[0083] (3) adding a mixed solution of bioenzyme JS-369 and hydrogen peroxide to the apocynum venetum cleaned in step (2) at a bath ratio of 1:50; wherein the amount of the apocynum venetum degumming agent is 15 g / L, the mass fraction of the hydrogen peroxide is 30%, the amount of the hydrogen peroxide is 4 g / L, heating at 80° C. for 45 min, first washing with hot water at 65° C. and then washing with cold water at 15° C., and drying at 60° C. to obtain apocynum venetum refined fiber.

[0084] The average whiteness of the apocynum venetum treated by the degumming method of this embodiment reaches 76.9%, the average strength reaches 9.2 cN, the average elongation reaches 0.56 mm, and the average breaking strength reaches 4.85 cN / dtex, indicating that the apocynum venetum treated by the present invention has higher whiteness and mechanical properties.

[0085] The physical and chemical properties of Apocynum venetum after the pilot test of the degumming methods of Example 3 and Example 4 of the present invention are shown in Table 5.

[0086] Table 5 Physical and chemical properties of Apocynum venetum fiber in pilot plant

[0087] Types of Apocynum venetum Example 3 Example 4 Weight loss rate (%) 46.5 46.0 Whiteness 76.5 74.2 Single fiber strength (cN) 8.5 8.2 Pectin content (%) 5.13 4.69

[0088] From the results in Table 5, it can be seen that the apocynum venetum degumming agent and degumming method of the present invention have stable performance in the pilot test, good degumming effect, good whiteness, good strength and low pectin residue.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for degumming apocynum venetum, characterized in that: The following steps are involved: (1) adding apocynum venetum to an acid solution, heating at 55° C.-65° C. for 55 min-75 min, and then washing; the bath ratio of the apocynum venetum to the acid solution is 1:(20-50); (2) adding alkali solution to the Apocynum venetum cleaned in step (1), heating at 65° C.-70° C. for 95 min-105 min, and then cleaning; the bath ratio of the Apocynum venetum to the alkali solution is 1:(20-50); (3) adding a mixed solution containing a complex enzyme and an oxidant to the apocynum venetum cleaned in step (2), heating at 70° C.-80° C. for 45 min-85 min, washing, and drying to obtain apocynum venetum refined fiber; the bath ratio of the apocynum venetum to the mixed solution is 1:(20-50); In the step (2), the alkali solution comprises the following components in weight percentages based on the mass of the Apocynum venetum: 4.5%-6.5% of sodium hydroxide, 4%-5% of sodium silicate, 2.5%-4.5% of sodium sulfite and 3%-3.5% of a penetrant; In the step (3), the complex enzyme comprises the following components: 60-64 parts of pectinase, 17-19 parts of hemicellulase, 10-13 parts of ligninase, 3-5 parts of laccase and 4-5 parts of xylanase.

2. The method for degumming apocynum venetum according to claim 1, wherein In the step (1), the acid in the acid solution is sulfuric acid, and the mass of the sulfuric acid is 1.25%-2% of the mass of the Apocynum venetum; the heating temperature is 60° C.-65° C., and the heating time is 55 min-60 min.

3. The method for degumming apocynum venetum according to claim 2, wherein In the step (1), the mass of the sulfuric acid is 1.75%-2% of the mass of the Apocynum venetum.

4. The method for degumming apocynum venetum according to claim 1, wherein In the step (2), the heating time is 100 min-105 min.

5. The method for degumming apocynum venetum according to claim 1, wherein In the step (3), the concentration of the complex enzyme in the mixed solution is 15 g / L-25 g / L.

6. The method for degumming apocynum venetum according to claim 1, wherein In the step (3), the oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide in the mixed solution is 4g / L-6g / L.

7. The method for degumming apocynum venetum according to claim 3, wherein In step (3), the cleaning is first performed with hot water and then with cold water.

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