A kind of apocynum fiber, its preparation method and application

Abstract

The present invention relates to a kind of apocynum venetum fiber, its preparation method and application, which includes first preparing an acid dipping solution by mixing oxalic acid and water, adding raw apocynum venetum for reaction, adding hydrogen peroxide and sulfuric acid after the reaction to continue treating the apocynum venetum, taking it out after the treatment is completed, washing, deoxidizing, adding a reagent mainly composed of sodium hydroxide for scouring, washing the fiber with water after the scouring is completed, and oiling and drying. The present invention can prepare apocynum venetum fiber for spinning with high breaking strength, low doubling rate and low residual gum rate.

Description

Technical Field

[0001] The present invention belongs to the field of textile and clothing processing, and particularly relates to a ramie fiber, a preparation method thereof, and an application thereof. Background Art

[0002] Ramie has excellent moisture absorption, air permeability and wearing comfort. In addition, ramie fiber also has excellent ultraviolet resistance and antibacterial effects, and is known as the "king of wild fibers", having great development potential in the textile field. China has the largest growing area of ramie, with a natural area of more than 20 million mu, mainly distributed in Xinjiang, Qinghai, Ningxia, Shandong and other places. Textile fibers can be extracted from the ramie phloem. Its fiber fineness is similar to that of cotton fiber and much finer than ramie fiber; the strength is close to that of ramie and about twice as high as that of cotton fiber; although the elongation at break is not as good as that of cotton fiber, it is better than ramie fiber; the length is close to that of cotton fiber. Therefore, like ramie, ramie is often used for degumming into single fibers and then spinning.

[0003] The main components of ramie are cellulose, hemicellulose, pectin and lignin. The content of cellulose is about 50%, the content of hemicellulose is about 10 - 20%, and the pectin content is about 10%. The presence of these non-cellulose substances (gums) not only affects the quality of the fiber, but also causes many inconveniences in subsequent processing. In addition, compared with ramie, the lignin content of ramie is relatively high, between 10 - 15%. Therefore, in the degumming of ramie, not only gums such as pectin and hemicellulose need to be removed, but also attention should be paid to the removal of lignin.

[0004] In the textile field, the existing degumming processes mainly include traditional alkali degumming, natural microbial degumming, bio-enzymatic degumming, bacterial degumming, organic solvent degumming, oxidative degumming, etc. The traditional alkali degumming process is the most widely used degumming method in industrial production, with stable degumming effect and excellent fiber properties obtained. However, this process has problems such as long process, high energy consumption, and serious pollution of degumming wastewater. In contrast, natural microbial degumming has lower cost and less pollution, but requires a longer time and is easily affected by weather conditions, resulting in unstable degumming quality. Bio-enzymatic degumming can significantly reduce pollution emissions, but due to the specificity of degumming enzymes and their high price, chemical reagents are usually required after bio-enzymatic treatment to meet the fiber standard for spinning. Bacterial degumming has higher efficiency, but there are great difficulties in strain screening and reaction condition control, which affects the degumming effect. The organic solvent degumming process can recycle the degumming liquid, but its solvent cost is high and the waste liquid needs further treatment. Among these degumming processes, oxidative degumming has received extensive attention from researchers due to its high efficiency, energy saving and good degumming quality. However, oxidative degumming also has problems such as strong oxidation, resulting in low strength of the degummed ramie fiber and uneven degumming.

[0005] The invention patent "A method for preparing ramie fibers by oxidative degumming with multiple-step feeding" with the publication number CN103233279B adopts a method of stepwise feeding during the oxidative degumming process to reduce the damage to cellulose caused by the strong oxidizing property generated by peroxides under alkaline conditions. However, this method is cumbersome to operate, and at the same time, it still inevitably causes cellulose depolymerization or damages the strength and elongation of fibers due to oxidation.

[0006] The invention patent "A method for degumming apocynum venetum" with the publication number CN116815334A uses a mixed solution of composite enzyme and oxidant to treat apocynum venetum. This process can effectively remove gums, natural pigments, etc. on apocynum venetum and increase whiteness. However, in some cases, the oxidant may inhibit the activity of the enzyme because the oxidant may change the structure or function of the enzyme. Therefore, it is necessary to further study the influence of the oxidant on the enzyme activity.

[0007] The invention patent "A method for preparing ramie fibers using a 2,2,6,6-tetramethylpiperidine-1-oxide free radical oxidation system" with the publication number CN106894097B uses a TEMPO selective oxidation system to degum ramie. During the oxidation process, most of the gums can be removed, and only the primary hydroxyl group at the C6 position of cellulose is selectively oxidized to 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, and the use cost of the catalyst TEMPO is relatively high.

[0008] Although the paper "Application of peracetic acid in the pretreatment process of ramie degumming" studied the influence of factors such as the addition amount of peracetic acid on the breaking strength of ramie fibers after degumming, the peracetic acid added in this process is a commercially available product, and peracetic acid can only selectively remove lignin, while its oxidative removal effect on hemicellulose and pectin in ramie non-cellulose substances is weak, resulting in a high residual gum rate of the degummed fibers. And commercially available peracetic acid is prone to decomposition due to poor stability, so it generally needs to be prepared on-site from two liquids A and B before use, and the operation is cumbersome. Summary of the Invention

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

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

[0011] (1) Immerse apocynum venetum in an acid dipping solution and react;

[0012] (2) Add hydrogen peroxide and sulfuric acid to the pickling solution after the reaction in step (1), react, and wash;

[0013] (3) Subject the product after washing in step (2) to deoxidation treatment and scouring treatment to obtain apocynum fibers.

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

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

[0016] Preferably, after adding hydrogen peroxide and sulfuric acid 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, in step (2), the reaction temperature is 60-80 °C, and the reaction time is 30-60 min.

[0018] Preferably, the deoxidation treatment in step (3) includes: adding the washed product to the deoxidizing solution and reacting.

[0019] Preferably, the deoxidizing solution 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 liquor ratio is 1:8-15.

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

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

[0022] After step (3) is completed, take out the hemp fibers, wash them with water, oil them, and dry them.

[0023] The present invention provides apocynum fibers prepared by the above method.

[0024] The present invention provides an application of the above apocynum fibers in the field of textile and clothing.

[0025] In the present invention, oxalic acid and water are first configured into an acid dipping solution, and raw ramie is added for reaction. After reacting for a period of time, a certain amount of hydrogen peroxide and sulfuric acid are added to continue treating the ramie. After the treatment is completed, the ramie fiber is taken out, washed, deoxidized, and then added with a reagent mainly composed of sodium hydroxide for scouring. After scouring is completed, the fiber is washed with water, oiled, and dried. By this method, ramie fibers for spinning with high breaking strength, low doubling rate, and low residual gum rate can be obtained, wherein the breaking strength reaches more than 4.5 cN / dtex, and the doubling rate is below 13,000 per 100 g.

[0026] In the present invention, the acidity of oxalic acid is controllable and no special acid and corrosion-resistant equipment is required. Oxalic acid has excellent ability to remove pectin and can specifically remove the pectin substances adhering to the surface of ramie; when ramie is oxidized under acidic conditions, the hemicellulose contained is more conducive to being hydrolyzed and removed; in addition, during the hydrolysis process of hemicellulose, a large amount of acetic acid will be released through deacetylation and oxidation. Hydrogen peroxide can oxidize acetic acid to generate peracetic acid in the solution. Peracetic acid has high oxidation ability and will generate hydronium ions during the reaction, selectively oxidize lignin by replacing the side chain of lignin, and convert the guaiacyl and syringyl groups of lignin into quinone compounds through Baeyer-Villiger oxidation reaction, and convert the aldehyde intermediates into low molecular weight carboxylic acids through Baeyer-Villiger oxidation reaction, so as to achieve the effect of removing lignin.

[0027] Beneficial effects

[0028] Aiming at the problem of high lignin content in ramie, the present invention adopts a method for preparing ramie fiber by oxalic acid pretreatment synergistically with self-generated peracetic acid for oxidative degumming of ramie. First, oxalic acid is used to remove pectin, and then hydrogen peroxide and sulfuric acid are used to remove hemicellulose; the acetic acid generated by the oxidative hydrolysis of hemicellulose is oxidized by an oxidant to generate peracetic acid in the system, and peracetic acid can oxidize the lignin in ramie without causing oxidative degradation of cellulose, ensuring the strength and elongation properties of the fiber. Alkali boiling can further remove non-cellulose substances, so as to achieve more sufficient degumming, and finally obtain spinnable ramie fibers with high breaking strength, low doubling rate, and low residual gum rate.

[0029] The process of the present invention is green, safe and sustainable. The hydrogen peroxide and peracetic acid used are both green oxidants; the self-generated peracetic acid can reduce the transportation link and reduce the safety accidents caused by collision, leakage, etc. during transportation. The operation is simple and convenient to use. Specific embodiments

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it 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 also fall within the scope defined by the appended claims of this application.

[0031] The test method for the performance indicators in the present invention:

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

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

[0034] The test method for the residual gum 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 with oxalic acid pretreatment synergistically self-generating peracetic acid, and the specific preparation process is as follows:

[0037] 10 g of raw Apocynum venetum, the liquor ratio is 1:8, the concentration of oxalic acid in the pickling solution is 2 g / L, the reaction time is 90 min, and the reaction temperature is 80 °C. After the reaction, hydrogen peroxide and sulfuric acid are added, so that the concentrations of hydrogen peroxide and sulfuric acid are 4 g / L and 0.05 g / L respectively, the reaction time is 60 min, and the reaction temperature is 80 °C. After the reaction, the hemp is washed. The washed product is added to a deoxidizing solution with a liquor ratio of 1:15 and a catalase concentration of 0.05 g / L, and the reaction is carried out at 30 °C for 30 min. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate and sodium tripolyphosphate are added to the deoxidizing solution, and their concentrations are 15 g / L, 2 g / L, 1 g / L and 1 g / L respectively. The boiling time is 180 min, the boiling temperature is 100 °C, and the pressure is 1 Mpa to obtain Apocynum venetum fiber.

[0038] Example 2

[0039] A method for preparing Apocynum venetum fiber by oxidative degumming of Apocynum venetum with oxalic acid pretreatment synergistically self-generating peracetic acid, and the specific preparation process is as follows:

[0040] 10 g of raw Apocynum venetum hemp, bath ratio is 1:10, the concentration of oxalic acid in the pickling solution is 4 g / L, the reaction time is 75 min, and the reaction temperature is 70 °C. After the reaction, hydrogen peroxide and sulfuric acid are added, so that the concentrations of hydrogen peroxide and sulfuric acid are 8 g / L and 0.1 g / L respectively, the reaction time is 45 min, and the reaction temperature is 70 °C. After the reaction, the hemp is washed. The washed product is added to a deoxidizing solution with a bath ratio of 1:10 and a catalase concentration of 1.5 g / L, and the reaction is carried out at 60 °C for 20 min. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate and sodium tripolyphosphate are added to the deoxidizing solution, so that their concentrations are 10 g / L, 3 g / L, 2 g / L and 2 g / L respectively, the scouring time is 120 min, the scouring temperature is 110 °C, and the pressure is 1.5 Mpa to obtain Apocynum venetum fiber.

[0041] Example 3

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

[0043] 10 g of raw Apocynum venetum hemp, bath ratio is 1:15, the concentration of oxalic acid in the pickling solution is 6 g / L, the reaction time is 45 min, and the reaction temperature is 60 °C. After the reaction, hydrogen peroxide and sulfuric acid are added, so that the concentrations of hydrogen peroxide and sulfuric acid are 10 g / L and 0.2 g / L respectively, the reaction time is 30 min, and the reaction temperature is 60 °C. After the reaction, the hemp is washed. The washed product is added to a deoxidizing solution with a bath ratio of 1:8 and a catalase concentration of 3 g / L, and the reaction is carried out at 90 °C for 10 min. Subsequently, sodium hydroxide, sodium sulfite, sodium carbonate and sodium tripolyphosphate are added to the deoxidizing solution, so that their concentrations are 6 g / L, 4 g / L, 3 g / L and 3 g / L respectively, the scouring time is 60 min, the scouring temperature is 100 °C, and the pressure is 2 Mpa to obtain Apocynum venetum fiber.

[0044] Comparative Example 1

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

[0046] 10 g of raw Apocynum venetum fiber, bath ratio of 1:15, add hydrogen peroxide and sulfuric acid, with the concentrations of hydrogen peroxide and sulfuric acid being 10 g / L and 0.2 g / L respectively, reaction time of 30 min, reaction temperature of 60 °C. After the reaction, add oxalic acid to make the concentration of oxalic acid 6 g / L, reaction time of 45 min, reaction temperature of 60 °C, and wash the fiber after the reaction. Add the washed product to the deoxidizing solution with a bath ratio of 1:8 and a catalase concentration of 3 g / L, react at 90 °C for 10 min, then add sodium hydroxide, sodium sulfite, sodium carbonate and sodium tripolyphosphate to the deoxidizing solution, with their concentrations being 6 g / L, 4 g / L, 3 g / L and 3 g / L respectively, boiling time of 60 min, boiling temperature of 100 °C, pressure of 2 Mpa to obtain Apocynum venetum fiber. The properties of the Apocynum venetum fiber prepared in Examples 1-3 and the comparative examples are shown in Table 1.

[0047] Table 1 Test results of the properties of Apocynum venetum fiber

[0048]

Claims

1. A preparation method of apocynum venetum fiber, comprising: (1) Immerse apocynum venetum into an acid dipping solution and react; (2) Add hydrogen peroxide and sulfuric acid into the acid dipping solution after the reaction in step (1), react and wash; after adding hydrogen peroxide and sulfuric acid into the acid dipping solution after the reaction, the concentration of hydrogen peroxide is 4 - 10 g / L, and the concentration of sulfuric acid is 0.05 - 0.2 g / L; the reaction temperature is 60 - 80 °C, and the reaction time is 30 - 60 min; (3) Perform deoxidation treatment and scouring treatment on the product after washing in step (2) to obtain apocynum venetum fiber; the components of the scouring agent solution used in the scouring treatment include that the concentration of sodium hydroxide is 6 - 15 g / L, the concentration of sodium sulfite is 2 - 4 g / L, the concentration of sodium carbonate is 1 - 3 g / L, and the concentration of sodium tripolyphosphate is 1 - 3 g / L.

2. The method according to claim 1, wherein The acid dipping solution in step (1) is an oxalic acid solution, and the concentration of oxalic acid is 2 - 6 g / L; In step (1), the liquor 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, wherein The deoxidation treatment in step (3) includes: adding the washed product into a deoxidizing solution and reacting.

4. The method according to claim 3, wherein The deoxidizing solution is a catalase solution, and the concentration is 0.05 - 3 g / L; the reaction temperature is 30 - 90 °C, the reaction time is 10 - 30 min, and the liquor ratio is 1:8 - 15.

5. The method according to claim 1, characterized in that In the scouring treatment in step (3), the scouring time is 60 - 180 min, the scouring temperature is 100 - 120 °C, and the pressure is 1 - 2 Mpa.

6. Apocynum venetum fiber prepared by the method according to claim 1.

7. Application of the apocynum venetum fiber according to claim 6 in the field of textile and clothing.

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