Method for preparing long linen yarn based on combined degumming of photocatalysis and pectinase

Abstract

The invention discloses a method for preparing long hemp yarn based on photocatalysis and pectinase combined degumming, which comprises the following steps: (1) beating hemp bast into hemp and carding to obtain parallel and straight long hemp bundles; (2) processing the long ramie bundles into continuous ramie strips on a slivering machine, drafting and combining the continuous ramie strips into parallel and straight long ramie strips with uniform evenness and structure, and drafting, twisting and winding the long ramie strips through a roving frame to obtain rough yarns; and (3) uniformly mixing the photocatalyst suspension and pectinase to prepare a degummed mixed solution, putting the hemp roving into the degummed mixed solution, performing illumination treatment, taking out the hemp roving after the illumination treatment is completed, and performing water washing and drying to obtain the degummed hemp roving. According to the method, pectin, lignin and other non-cellulose colloid components in the jute fibers are removed by utilizing the photocatalyst and pectinase, the degumming condition is mild, the damage effect on the jute fibers is small, the energy consumption is relatively low, an alkaline solution is not used in the degumming process, the generated waste liquid is less, and the environmental pollution is small.

Description

Technical Field

[0001] The invention relates to the technical field of textile processing, and in particular to a method for preparing long linen yarn based on photocatalysis and pectinase combined degumming. Background Art

[0002] Hemp is a natural bast fiber. The cultivation and production of hemp can bring good environmental and economic benefits. It is a high-potential agricultural product. Hemp fiber resources are abundant, with the characteristics of long fiber, high strength, small elongation, fast moisture absorption and release, etc. The spun yarn can be made into various hemp fabrics, hoses, conveyor belts and various sewing hemp threads, etc., for clothing, decoration, industrial and agricultural production and national defense construction. Hemp fiber has a bast fiber structure, which is a single cellulose fibril bonded together by a colloid substance. The colloid substance is mainly composed of hemicellulose, pectin, wax, water-soluble materials and lignin. Since a large amount of colloid substances will increase the toughness and yellowness of hemp fibers, it directly limits their further use. It is very necessary to extract high-quality hemp long fibers from hemp without sacrificing the physical properties or chemical structure of cellulose.

[0003] At present, there are two main methods for preparing long linen yarn: (1) wet spinning method: the coarse yarn is processed through the boiling and bleaching process to swell and remove part of the colloid on the fiber to soften the fiber and reduce the bonding force between the fibers. Then, it is stretched through a water tank (with water, penetrant, softener, etc.) on a wet spinning machine to split and thin the process fibers into finer fiber bundles, which are then twisted into yarn and wound on a bobbin; (2) dry spinning method: the coarse yarn is directly spun on a dry spinning machine to form long linen dry spinning yarn. Of the above two methods, wet spinning yarn has uniform dryness, high strength, less hairiness, and fine spinnable density, while dry spinning cannot effectively remove the colloid on the linen fiber, which affects its use. The boiling and bleaching process in the wet spinning method uses chemical reagents such as caustic soda to react and degrade non-cellulose components such as pectin, hemicellulose and lignin in the linen bast, but this method will produce a lot of pollution and damage cellulose. Compared with traditional alkali degumming, enzyme degumming can significantly reduce pollution emissions, but the degumming enzyme has a single function, which limits the efficiency and effect of degumming and requires chemical reagents to assist; organic solvent degumming can recycle the degumming liquid, but the solvent cost is extremely high and the wastewater also needs further treatment. Therefore, it is urgent to develop a degumming method with mild conditions and low environmental pollution to degumming hemp yarn to obtain long hemp yarn. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing long linen yarn based on photocatalysis and pectinase combined degumming. The method has a simple operation process, mild reaction conditions, little environmental pollution, good degumming effect, and little damage to the linen yarn.

[0005] The technical solution adopted by the present invention is:

[0006] A method for preparing long linen yarn based on photocatalysis and pectinase combined degumming, comprising the steps of:

[0007] (1) beating hemp bast into hemp, and after the pre-combing preparation process, combing on a combing machine to obtain parallel and straight long hemp bundles;

[0008] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by 3 to 5 drawing frames to form long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0009] (3) uniformly mixing the photocatalyst suspension and the pectinase solution to prepare a degumming mixed solution, and pouring the degumming mixed solution into a glass reactor, and then placing the hemp roving into the degumming mixed solution and subjecting it to light treatment. After the light treatment is completed, the hemp roving is taken out, and washed and dried to obtain a degummed hemp roving;

[0010] (4) The degummed flax roving is drawn on a wet spinning frame, twisted into yarn, and then dried and wound onto a bobbin to obtain finished flax roving, i.e., long flax yarn.

[0011] Furthermore, the pre-combing preparation process in step (1) includes humidification and milk supply, health care, bundle separation, and initial combing.

[0012] Furthermore, the photocatalyst in step (3) can be a catalyst that can be excited within the visible light wavelength range, such as TiO2-CQDs, ZnO-CQDs and other composite photocatalysts containing carbon quantum dots and other types of photocatalysts, such as ZnIn2S4.

[0013] In the above technical solution, the photocatalyst is a catalyst that can be excited within the visible light wavelength range, such as TiO2-CQDs, ZnO-CQDs, ZnIn2S4 and other photocatalysts. This type of photocatalyst can be excited within the visible light wavelength range, and visible light accounts for 45% of the total energy of sunlight, and its light utilization rate is high, thereby improving the degumming effect. Further, the amount of the photocatalyst used in step (3) is 1 to 5 g / kg of hemp roving.

[0014] Furthermore, in the step (3), the dosage of pectinase is 2000-10000U / kg of hemp roving.

[0015] Furthermore, in the step (3), the solid-bath ratio of the flax roving to the degumming mixed solution is 1:10-100.

[0016] Furthermore, the illumination treatment time in step (3) is 20 to 60 hours.

[0017] Furthermore, the light source used in the illumination treatment in step (3) is sunlight or simulated sunlight, and the simulated sunlight is a light emitting diode or a xenon lamp.

[0018] Furthermore, the hemp fiber is one of ramie, hemp, ramie, kenaf or jute.

[0019] The beneficial effects of the present invention are:

[0020] The invention provides a method for preparing long linen yarn based on photocatalysis and pectinase combined degumming, which utilizes photocatalyst and pectinase to remove wax, pectin, lignin, hemicellulose and other colloids in linen fiber, has mild degumming conditions, high degumming efficiency, little damage to the linen yarn, and improves the strength and evenness of the yarn; moreover, the energy consumption is low, no alkaline solution is used in the degumming process, less waste liquid is generated, and the environmental pollution is small. DETAILED DESCRIPTION

[0021] The present invention provides a method for preparing long linen yarn based on photocatalysis and pectinase combined degumming. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Example 1

[0023] This embodiment provides a method for preparing long linen yarn by degumming based on photocatalysis and pectinase, comprising the steps of:

[0024] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0025] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0026] (3) 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension and 2000 U of pectinase solution were mixed to prepare a degumming mixed solution, and the degumming mixed solution was poured into a 30 L glass reactor, wherein the pectinase activity content was 2 U / mL, and then 1000 g of hemp roving was placed in the degumming mixed solution, and water was added to make the solid-bath ratio of the hemp roving and the degumming mixed solution 1:20, and the solution was placed under sunlight for 4 days, specifically, 12 hours of light treatment and 12 hours of dark treatment, which was repeated for 4 days. After the light treatment was completed, the hemp roving was taken out, washed with water, and dried to obtain degummed hemp roving;

[0027] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0028] Example 2

[0029] This embodiment provides a method for preparing long linen yarn by degumming based on photocatalysis and pectinase, comprising the steps of:

[0030] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0031] (2) The long flax bundles are processed into continuous flax strips on a strip forming machine, and then drawn and combined by a five-pass drawing frame to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0032] (3) 500 ml of 10 g / L ZnIn2S4 photocatalyst suspension and 8000 U of pectinase solution were mixed evenly to prepare a degumming mixed solution, and the degumming mixed solution was poured into a 30 L glass reactor, and then 1000 g of hemp roving was placed in the degumming mixed solution, and water was added to make the solid-bath ratio of the hemp roving and the degumming mixed solution be 1:60, and the hemp roving was treated with continuous illumination by LED lamp for 3 days. After the illumination treatment was completed, the hemp roving was taken out, and it was washed and dried to obtain degummed hemp roving;

[0033] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0034] Comparative Example 1

[0035] This comparative example provides a method for preparing long linen yarn by degumming using a photocatalyst, comprising the steps of:

[0036] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0037] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0038] (3) Pour 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension into a 30 L glass reactor to prepare a degumming mixed solution, then put 1000 g of hemp roving into the degumming mixed solution, add water to make the solid bath ratio of hemp roving and degumming mixed solution be 1:20, and then treat it in the dark for 4 days. After the treatment is completed, take out the hemp roving, wash it with water, and dry it to obtain degummed hemp roving;

[0039] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0040] Comparative Example 2

[0041] This comparative example provides a method for preparing long linen yarn by degumming using a photocatalyst, comprising the steps of:

[0042] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0043] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0044] (3) Pour 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension into a 30 L glass reactor to prepare a degumming mixed solution, then put 1000 g of hemp roving into the degumming mixed solution, add water to make the solid-bath ratio of hemp roving and degumming mixed solution 1:20, and place it under sunlight for 4 days, specifically, 12 hours of light treatment and 12 hours of dark treatment, which is repeated for 4 days. After the treatment is completed, take out the hemp roving, wash it with water, and dry it to obtain degummed hemp roving;

[0045] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0046] Comparative Example 3

[0047] This comparative example provides a method for preparing long linen yarn by degumming with pectinase, comprising the steps of:

[0048] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0049] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0050] (3) Pour 2000U pectinase solution into a 30L glass reactor to prepare a degumming mixed solution, then put 1000g of hemp roving into the degumming mixed solution, the solid bath ratio of the hemp roving to the degumming mixed solution is 1:20, and then treat it in the dark for 4 days. After the treatment is completed, take out the hemp roving, wash it with water, and dry it to obtain degummed hemp roving;

[0051] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0052] Comparative Example 4

[0053] This comparative example provides a method for preparing long linen yarn by degumming with pectinase, comprising the steps of:

[0054] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0055] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0056] (3) Pour 2000U pectinase solution into a 30L glass reactor to prepare a degumming mixed solution, then put 1000g of hemp roving into the degumming mixed solution, add water so that the solid-bath ratio of the hemp roving and the degumming mixed solution is 1:20, and place it under sunlight for 4 days, specifically, 12 hours of light treatment and 12 hours of dark treatment, which is repeated for a total of 4 days. After the treatment is completed, take out the hemp roving, wash it with water, and dry it to obtain degummed hemp roving;

[0057] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0058] Comparative Example 5

[0059] This comparative example provides a method for preparing long linen yarn based on photocatalysis and pectinase combined degumming, comprising the steps of:

[0060] (1) beating the hemp bast into hemp, and after the preparatory processes such as humidification, curing, bundle division, and initial combing, combing is performed on a combing machine to obtain parallel and straight long hemp bundles with a certain length, linear density and weight;

[0061] (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by four drawing machines to produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving;

[0062] (3) 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension and 2000 U of pectinase solution were mixed to prepare a degumming mixed solution, and the solution was poured into a 30 L glass reactor, and then 1000 g of hemp roving was placed in the degumming mixed solution, and water was added to make the solid bath ratio of the hemp roving and the degumming mixed solution 1:20, and then the solution was treated in the dark for 4 days. After the treatment, the hemp roving was taken out, washed with water, and dried to obtain degummed hemp roving;

[0063] (4) The degummed flax roving is passed through a water tank (water, penetrant, and softener are added to the water tank) on a wet spinning machine and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn and, after drying, is wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0064] In addition, the chemical composition test of the degummed hemp fibers prepared in the above-mentioned Example 1 and Comparative Examples 1-5 was carried out, and the test results are shown in Table 1. The physical properties test of the degummed hemp fibers prepared in Example 1 and Comparative Example 4 was carried out, and the test results are shown in Table 2.

[0065] The above chemical composition test and physical property test methods are as follows:

[0066] Test method for chemical composition: Refer to GB 5889-1986 "Quantitative analysis method for chemical composition of ramie" to test the residual gum rate of degummed hemp fiber.

[0067] Test method for fineness: Refer to GB / T 6100-2007 "Test method for linear density of cotton fibers - mid-section weighing method" to test the fineness of degummed hemp fibers.

[0068] Test method for bundle fiber strength: refer to GB / T 5882-1986 "Test method for breaking strength of ramie bundle fibers" to test the strength of degummed hemp fibers.

[0069] Table 1

[0070]

[0071] Table 2

[0072]

[0073] It can be seen from Table 1 above that the removal rate of wax, pectin, lignin, hemicellulose and other colloids of the long linen yarn prepared in Example 1 is the highest, indicating that the combined degumming effect of TiO2-CQDs and pectinase under light treatment is good; compared with Example 1, Comparative Example 5 is treated under dark conditions using TiO2-CQDs and pectinase, and its wax, pectin, lignin, hemicellulose and other contents are higher than those in Example 1; in addition, Comparative Example 1 is treated only with TiO2-CQDs under dark conditions, and the content of each colloid is still very high; Comparative Example 2 is treated only with TiO2-CQDs under light conditions, and the content of each colloid is still very high, and lignin and hemicellulose are only slightly reduced; Comparative Example 3 is treated in the dark using pectinase, and part of pectin, wax, lignin, hemicellulose, etc. are removed; compared with Comparative Example 3, Comparative Example 4 is treated with pectinase under light, and relatively more pectin, wax, lignin, hemicellulose, etc. are removed.

[0074] It can be seen from Table 2 above that Example 1 adopts a TiO2-CQDs photocatalyst combined with a pectinase degumming process. After degumming, the fineness of the flax yarn is 41 Nm, the breaking strength is 34 cN / dtex, the yarn is strong, and the yarn is uniform. Compared with the single pectinase treatment in Comparative Example 4, its breaking strength remains basically unchanged, indicating that photocatalysis has little effect on fiber performance.

[0075] It should be noted that some parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0076] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing long linen yarn based on photocatalysis and pectinase combined degumming, characterized in that: Includes steps: (1) beating hemp bast into hemp, and after the pre-combing preparation process, combing on a combing machine to obtain parallel and straight long hemp bundles; (2) The long flax bundles are processed into continuous flax strips on a slitting machine, and then drawn and combined by 3 to 5 drawing frames to form long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain roving; (3) uniformly mixing the photocatalyst suspension and the pectinase solution to prepare a degumming mixed solution, and pouring the degumming mixed solution into a glass reactor, and then placing the hemp roving into the degumming mixed solution and subjecting it to light treatment. After the light treatment is completed, the hemp roving is taken out, and washed and dried to obtain a degummed hemp roving; (4) The degummed flax roving is drawn on a wet spinning frame, twisted into yarn, and then dried and wound onto a bobbin to obtain finished flax roving, i.e., long flax yarn.

2. The method for preparing long linen yarn based on photocatalysis and pectinase combined degumming according to claim 1 is characterized in that: The pre-combing preparation process in step (1) includes humidification, milking, health care, bundling, and initial combing.

3. The method for preparing flax yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: The photocatalyst in step (3) is a catalyst that can be excited within the visible light wavelength range.

4. The method for preparing flax yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: The amount of the photocatalyst used in step (3) is 1-5 g / kg of the flax roving.

5. The method for preparing long linen yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: The dosage of pectinase in the step (3) is 2000-10000U / kg of flax yarn.

6. The method for preparing long linen yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: In the step (3), the solid-bath ratio of the flax roving to the degumming mixed solution is 1:10-100.

7. The method for preparing long linen yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: The illumination treatment time in step (3) is 2 to 5 days.

8. The method for preparing flax yarn based on photocatalysis and pectinase combined degumming according to claim 1, characterized in that: The light source used in the illumination treatment in step (3) is sunlight or simulated sunlight.

9. A method for preparing flax yarn based on photocatalysis and pectinase combined degumming according to any one of claims 1 to 8, characterized in that: The hemp fiber is one of ramie, hemp, apocynum, kenaf or jute.

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