Apocynum venetum fiber and preparation method and application thereof

Abstract

The invention relates to apocynum venetum fiber and a preparation method and application thereof. The preparation method comprises the following steps: preparing oxalic acid and water into a pickling solution, adding raw apocynum venetum to react, adding hydrogen peroxide and sulfuric acid to continuously treat apocynum venetum after the reaction, taking out the apocynum venetum after the treatment is finished, washing, deoxidizing, adding a reagent mainly containing sodium hydroxide to boil, and drying to obtain the apocynum venetum fiber. And after the scouring is finished, cleaning the fibers with water, feeding oil, and drying. The apocynum venetum fiber for spinning, which is high in breaking strength, low in doubling rate and low in residual gum rate, can be prepared.

Description

Technical Field

[0001] The invention belongs to the field of textile and garment processing, and particularly relates to apocynum venetum fiber and a preparation method and application thereof. Background Art

[0002] Apocynum venetum boasts excellent moisture absorption, breathability, and comfort. Furthermore, apocynum venetum fiber exhibits excellent UV resistance and antibacterial properties, earning it the nickname "King of Wild Fibers." It holds great potential for development in the textile industry. my country boasts the largest apocynum venetum growing area, with over 20 million mu (approximately 1.5 acres) of natural growth, primarily in Xinjiang, Qinghai, Ningxia, and Shandong. Textile fibers can be extracted from the phloem of apocynum venetum. These fibers are similar in fineness to cotton fibers and much finer than ramie fibers. Their strength is similar to ramie fibers, approximately double that of cotton fibers. While their elongation at break is lower than that of cotton fibers, it is superior to that of ramie fibers. Their length is similar to that of cotton fibers. Therefore, apocynum venetum, like ramie, is often degummed into single fibers for spinning.

[0003] The main components of apocynum venetum are cellulose, hemicellulose, pectin, and lignin. The cellulose content is approximately 50%, the hemicellulose content is around 10-20%, and the pectin content is around 10%. The presence of these non-cellulose substances (colloids) not only affects the fiber quality but also causes numerous inconveniences during subsequent processing. Furthermore, compared to ramie, apocynum venetum has a higher lignin content, ranging from 10-15%. Therefore, apocynum venetum degumming not only requires the removal of pectin, hemicellulose, and other colloids, but also emphasizes the removal of lignin.

[0004] In the textile industry, existing degumming processes mainly include traditional alkali degumming, natural microbial degumming, bio-enzyme degumming, bacterial degumming, organic solvent degumming, and oxidative degumming. Traditional alkali degumming is the most widely used degumming method in industrial production, with stable degumming results and excellent fiber properties. However, this process is plagued by long steps, high energy consumption, and severe pollution from degumming wastewater. In contrast, natural microbial degumming is less expensive and less polluting, but it takes longer and is easily affected by weather conditions, resulting in unstable degumming quality. Bio-enzyme degumming can significantly reduce pollution emissions, but because the degumming enzymes are specific and expensive, chemical reagents are usually required after the bio-enzyme treatment to meet spinning fiber standards. Bacterial degumming is more efficient, but there are significant difficulties in strain selection and reaction condition control, which affect the degumming effect. Organic solvent degumming processes can recycle the degumming solution, but the solvent costs are high and the wastewater requires further treatment. Among these degumming processes, oxidative degumming has attracted widespread attention from researchers due to its high efficiency, energy saving, and excellent degumming quality. However, oxidative degumming also has the problem of strong oxidizing effect, resulting in low strength of degummed hemp fibers and uneven degumming.

[0005] The invention patent with publication number CN103233279B, "A method for preparing ramie fiber by oxidative degumming and multiple step-by-step feeding", adopts a step-by-step feeding method during the oxidative degumming process to reduce the damage to cellulose caused by the strong oxidizing properties of peroxide under alkaline conditions. However, this method is cumbersome to operate and will inevitably cause cellulose depolymerization or damage the strength and elongation of the fiber due to oxidation.

[0006] Patent application CN116815334A, "A Method for Degumming Apocynum venetum," uses a mixed solution of a complex enzyme and an oxidant to treat the apocynum venetum. This process effectively removes gum and natural pigments from the apocynum venetum and increases its whiteness. However, in some cases, the oxidant may inhibit enzyme activity due to changes in its structure or function. Therefore, further research is needed to investigate the effects of oxidants on enzyme activity.

[0007] The invention patent with publication number CN106894097B, "A method for preparing ramie fiber using 2,2,6,6-tetramethylpiperidine-1-oxide free radical oxidation system", uses the TEMPO selective oxidation system to degumming ramie. Most of the colloid can be removed during the oxidation process, and only the primary hydroxyl group at the C6 position of cellulose is selectively oxidized to a carboxyl group. The strength and elongation of the product are better than those of the alkaline hydrogen peroxide degumming process. However, the oxidant used in this reaction is sodium hypochlorite, and chloride ions will cause pollution and damage to the environment. In addition, the cost of using the catalyst TEMPO is relatively high.

[0008] While the paper "Application of Peracetic Acid in Ramie Degumming Pretreatment" investigated the effects of factors such as the amount of peracetic acid added on the breaking strength of degummed ramie fibers, the peracetic acid used in this process was a commercially available product. Furthermore, peracetic acid selectively removes lignin, while having a weak oxidative effect on the hemicellulose and pectin in the non-cellulosic materials of ramie, resulting in a high residual glue content in the fibers after degumming. Furthermore, commercially available peracetic acid is unstable and easily decomposed, requiring the on-site preparation of two liquids, A and B, prior to use, which is cumbersome. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide apocynum venetum fiber and its preparation method and application, and particularly relates to a method for preparing apocynum venetum fiber by oxidative degumming of apocynum venetum through oxalic acid pretreatment in conjunction with self-generated peracetic acid. The method overcomes the technical problems in the prior art of low breaking strength of hemp fiber, poor degumming uniformity (high doubling rate), high residual glue rate and environmental pollution caused by chlorine-containing oxidants during oxidative degumming.

[0010] The present invention provides a method for preparing apocynum venetum fiber, comprising:

[0011] (1) Soaking the Apocynum venetum in an acid solution for reaction;

[0012] (2) adding hydrogen peroxide and sulfuric acid to the pickling solution after the reaction in step (1), reacting, and washing;

[0013] (3) The product after washing in step (2) is subjected to deoxidation treatment and scouring treatment to obtain apocynum venetum fiber.

[0014] Preferably, the pickling solution in step (1) is an oxalic acid solution, and the oxalic acid concentration is 2 to 6 g / L.

[0015] Preferably, in step (1), the bath ratio is 1:8-15, the reaction time is 45-90 min, and the reaction temperature is 60-80°C.

[0016] Preferably, after hydrogen peroxide and sulfuric acid are added to the pickling solution after the reaction in step (2), the concentration of hydrogen peroxide is 4-10 g / L, and the concentration of sulfuric acid is 0.05-0.2 g / L.

[0017] Preferably, the reaction temperature in step (2) is 60-80° C., and the reaction time is 30-60 min.

[0018] Preferably, the deoxygenation treatment in step (3) comprises: adding the washed product into a deoxygenation liquid for reaction.

[0019] Preferably, the deoxygenated liquid is a catalase solution with a concentration of 0.05-3 g / L; the reaction temperature is 30-90° C., the reaction time is 10-30 min, and the bath ratio is 1:8-15.

[0020] Preferably, the scouring treatment in step (3) includes adding a reagent mainly composed of sodium hydroxide to the deoxygenated liquid after deoxygenation to obtain a scouring agent solution, and then scouring.

[0021] Furthermore, the scouring agent solution components used in the scouring treatment in step (3) include sodium hydroxide with a concentration of 6 to 15 g / L, sodium sulfite with a concentration of 2 to 4 g / L, sodium carbonate with a concentration of 1 to 3 g / L, and sodium tripolyphosphate with a concentration of 1 to 3 g / L; the scouring treatment is performed for a scouring time of 60 to 180 min, a scouring temperature of 100 to 120° C., and a pressure of 1 to 2 MPa.

[0022] After step (3) is completed, the hemp fibers are taken out, washed with water, oiled, and dried.

[0023] The invention provides apocynum venetum fiber prepared by the method.

[0024] The present invention provides an application of the apocynum venetum fiber in the field of textiles and clothing.

[0025] The present invention first prepares a pickling solution by mixing oxalic acid and water, adds raw apocynum venetum to react, and after a period of reaction, adds a certain amount of hydrogen peroxide and sulfuric acid to continue treating the apocynum venetum. After the treatment is completed, the hemp fibers are removed, washed and deoxidized, and then scouring is performed with a reagent mainly composed of sodium hydroxide. After scouring, the fibers are washed with water, oiled, and dried. This method can produce apocynum venetum fibers for spinning with high breaking strength, low parallel yarn rate, and low residual rubber rate, wherein the breaking strength reaches 4.5 cN / dtex or higher and the parallel yarn rate is 13,000 strands / 100g or lower.

[0026] The acidity of the oxalic acid in the present invention is controllable and does not require special acid-resistant and corrosion-resistant equipment. Oxalic acid has excellent pectin removal capabilities and can specifically remove pectin substances adhering to the surface of apocynum venetum. When apocynum venetum is oxidized under acidic conditions, the hemicellulose contained therein is more easily hydrolyzed and removed. In addition, during the hydrolysis of the hemicellulose, a large amount of acetic acid is released through deacetylation and oxidation. Hydrogen peroxide can oxidize the acetic acid to spontaneously generate peracetic acid in the solution. Peracetic acid has a high oxidizing ability and produces hydronium ions during the reaction process. It selectively oxidizes lignin by replacing the side chains of lignin, converting the guaiacyl and syringyl groups of the lignin into quinone compounds through the Baeyer-Villiger oxidation reaction. Aldehyde intermediates are also converted into low-molecular-weight carboxylic acids through the Baeyer-Villiger oxidation reaction, thereby achieving the effect of removing lignin.

[0027] Beneficial effects

[0028] To address the problem of high lignin content in apocynum venetum, the present invention utilizes an oxalic acid pretreatment combined with self-generated peracetic acid for oxidative degumming to produce apocynum venetum fiber. Oxalic acid is first used to remove pectin, followed by hydrogen peroxide and sulfuric acid to remove hemicellulose. Acetic acid produced by the oxidative hydrolysis of hemicellulose is then oxidized by an oxidant to generate peracetic acid within the system. The peracetic acid oxidizes the lignin in apocynum venetum without causing oxidative degradation of cellulose, thereby ensuring the fiber's strength and elongation properties. Alkali cooking further removes non-cellulosic substances, achieving more complete degumming. The resulting spinnable apocynum venetum fiber exhibits high breaking strength, low parallel stranding rate, and low residual glue content.

[0029] The process of the invention is green, safe and sustainable. The hydrogen peroxide and peracetic acid used are both green oxidants. The self-generated peracetic acid can reduce transportation links and reduce safety accidents caused by collisions, leakages, etc. during transportation. The process is simple to operate and easy to use. DETAILED DESCRIPTION

[0030] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0031] Testing methods for performance indicators in the present invention:

[0032] The test method for breaking strength of apocynum venetum fiber is: GB 5886-1986;

[0033] The test method for the parallel yarn rate of apocynum venetum fiber is: GB / T 32753-2016;

[0034] The test method for residual rubber rate of apocynum venetum fiber is: GB / T18147.2-2008.

[0035] Example 1

[0036] A method for preparing apocynum venetum fiber by oxidative degumming of apocynum venetum by oxalic acid pretreatment in combination with self-generated peracetic acid, wherein the specific preparation process is as follows:

[0037] 10g of raw apocynum venetum was prepared in a bath ratio of 1:8, with an oxalic acid concentration of 2 g / L in the pickling solution. The reaction time was 90 minutes and the reaction temperature was 80°C. Hydrogen peroxide and sulfuric acid were added after the reaction to a concentration of 4 g / L and 0.05 g / L, respectively. The reaction time was 60 minutes and the reaction temperature was 80°C. The apocynum venetum fiber was then washed. The washed product was added to a deoxygenated solution with a bath ratio of 1:15 and a catalase concentration of 0.05 g / L. The reaction was continued at 30°C for 30 minutes. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate, and sodium tripolyphosphate were added to the deoxygenated solution to a concentration of 15 g / L, 2 g / L, 1 g / L, and 1 g / L, respectively. The fiber was scoured for 180 minutes at a temperature of 100°C and a pressure of 1 MPa to obtain apocynum venetum fiber.

[0038] Example 2

[0039] A method for preparing apocynum venetum fiber by oxidative degumming of apocynum venetum by oxalic acid pretreatment in combination with self-generated peracetic acid, wherein the specific preparation process is as follows:

[0040] 10g of raw apocynum venetum was prepared in a bath ratio of 1:10, with an oxalic acid concentration of 4g / L in the pickling solution. The reaction time was 75min and the reaction temperature was 70°C. Hydrogen peroxide and sulfuric acid were added after the reaction to a concentration of 8g / L and 0.1g / L, respectively. The reaction time was 45min and the reaction temperature was 70°C. The apocynum venetum fiber was then washed. The washed product was added to a deoxygenated solution with a bath ratio of 1:10 and a catalase concentration of 1.5g / L. The reaction was carried out at 60°C for 20min. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate, and sodium tripolyphosphate were added to the deoxygenated solution to a concentration of 10g / L, 3g / L, 2g / L, and 2g / L, respectively. The fiber was scoured for 120min at a temperature of 110°C and a pressure of 1.5MPa to obtain apocynum venetum fiber.

[0041] Example 3

[0042] A method for preparing apocynum venetum fiber by oxidative degumming of apocynum venetum by oxalic acid pretreatment in combination with self-generated peracetic acid, wherein the specific preparation process is as follows:

[0043] 10g of raw apocynum venetum was prepared with a bath ratio of 1:15, an oxalic acid concentration of 6g / L in the pickling solution, a reaction time of 45min, and a reaction temperature of 60°C. Hydrogen peroxide and sulfuric acid were added after the reaction to a concentration of 10g / L and 0.2g / L, respectively. The reaction time was 30min at 60°C, and the hemp was washed. The washed product was added to a deoxygenated solution with a bath ratio of 1:8 and a catalase concentration of 3g / L. The reaction was carried out at 90°C for 10min. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate, and sodium tripolyphosphate were added to the deoxygenated solution to a concentration of 6g / L, 4g / L, 3g / L, and 3g / L, respectively. The scouring time was 60min at a temperature of 100°C and a pressure of 2MPa to obtain apocynum venetum fiber.

[0044] Comparative Example 1

[0045] A method for preparing apocynum venetum fiber by oxidative degumming of apocynum venetum by oxalic acid pretreatment in combination with self-generated peracetic acid, wherein the specific preparation process is as follows:

[0046] 10g of raw apocynum venetum was prepared in a bath ratio of 1:15. Hydrogen peroxide and sulfuric acid were added to concentrations of 10g / L and 0.2g / L, respectively. The reaction time was 30 minutes at a temperature of 60°C. Oxalic acid was added after the reaction to a concentration of 6g / L. The reaction time was 45 minutes at a temperature of 60°C. The apocynum venetum fiber was then washed. The washed product was added to a deoxygenated solution with a bath ratio of 1:8 and a catalase concentration of 3g / L. The solution was reacted at 90°C for 10 minutes. Sodium hydroxide, sodium sulfite, sodium carbonate, and sodium tripolyphosphate were then added to the deoxygenated solution to concentrations of 6g / L, 4g / L, 3g / L, and 3g / L, respectively. The fiber was scoured for 60 minutes at a temperature of 100°C and a pressure of 2 MPa to produce apocynum venetum fiber. The properties of the apocynum venetum fibers produced in Examples 1-3 and the Comparative Example are shown in Table 1.

[0047] Table 1 Test results of apocynum venetum fiber properties

Claims

1. A method for preparing apocynum venetum fiber, comprising: (1) Soaking the apocynum venetum in an acid solution for reaction; (2) adding hydrogen peroxide and sulfuric acid to the pickling solution after the reaction in step (1), reacting, and washing; (3) The product after washing in step (2) is subjected to deoxygenation treatment and scouring treatment to obtain apocynum venetum fiber.

2. The method according to claim 1, characterized in that: The pickling solution in step (1) is an oxalic acid solution, and the oxalic acid concentration is 2 to 6 g / L; In step (1), the bath ratio is 1:8-15, the reaction time is 45-90 min, and the reaction temperature is 60-80° C.

3. The method according to claim 1, characterized in that: In the step (2), hydrogen peroxide and sulfuric acid are added to the pickling solution after the reaction is completed, wherein the concentration of hydrogen peroxide is 4-10 g / L, and the concentration of sulfuric acid is 0.05-0.2 g / L.

4. The method according to claim 1, characterized in that: In the step (2), the reaction temperature is 60-80° C. and the reaction time is 30-60 min.

5. The method according to claim 1, characterized in that: The deoxygenation treatment in step (3) comprises: adding the washed product into a deoxygenation liquid for reaction.

6. The method according to claim 5, characterized in that: The deoxygenated liquid is a catalase solution with a concentration of 0.05-3 g / L; the reaction temperature is 30-90° C., the reaction time is 10-30 min, and the bath ratio is 1: 8-15.

7. The method according to claim 1, characterized in that: The scouring treatment in step (3) includes adding a reagent mainly composed of sodium hydroxide to the deoxygenated liquid after the deoxygenation treatment to obtain a scouring agent solution, and then scouring.

8. The method according to claim 1, characterized in that: The scouring agent solution used in the scouring treatment in step (3) comprises sodium hydroxide at a concentration of 6 to 15 g / L, sodium sulfite at a concentration of 2 to 4 g / L, sodium carbonate at a concentration of 1 to 3 g / L, and sodium tripolyphosphate at a concentration of 1 to 3 g / L; the scouring treatment is performed for a scouring time of 60 to 180 min, a scouring temperature of 100 to 120° C., and a pressure of 1 to 2 MPa.

9. A type of apocynum venetum fiber prepared by the method of claim 1.

10. Use of the apocynum ramie fiber according to claim 9 in the field of textiles and clothing.

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