Method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming

Abstract

The invention discloses a method for preparing long hemp yarn based on photocatalysis and alkali treatment combined degumming, which comprises the following steps: (1) beating hemp bast into hemp, and carding to obtain long hemp bundles; (2) processing the long hemp bundles into hemp strips, drafting, combining, drafting and twisting, and winding to obtain rough hemp yarns; (3) putting the rough hemp yarn into a degumming solution containing a photocatalyst for light treatment, taking out the rough hemp yarn after light treatment, putting the rough hemp yarn into a container containing ethanolamine, heating for 3-6 hours, taking out the rough hemp yarn, washing with water, and drying to obtain degummed rough hemp yarn; and (4) drafting and twisting the degummed hemp roving to obtain the long hemp yarn. According to the method, pectin, lignin and other non-cellulose colloid components in the fibrilia are removed through the combination of the photocatalyst and the organic alkali, the degumming condition is mild, the damage effect on the fibrilia is small, the organic alkali can be recycled, the generated waste liquid is little, and the pollution to the environment 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 alkali treatment 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 role of degumming enzymes is single, which limits the efficiency and effect of degumming and requires the assistance of chemical reagents; organic solvent degumming can recycle the degumming liquid, but the solvent cost is extremely high, and the wastewater also needs further treatment. In addition, the degumming effect of organic solvents is limited, and there is also the problem of incomplete degumming. 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 alkali treatment combined degumming. The method has mild reaction conditions, little environmental pollution, good degumming effect, and less damage to linen fibers.

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

[0006] A method for preparing long linen yarn based on photocatalysis and alkali treatment 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 produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain flax roving;

[0009] (3) adding a photocatalyst into a glass reactor to prepare a degumming solution, and placing the hemp roving into the degumming solution for light treatment, taking out the hemp roving after the light treatment is completed, and then placing the hemp roving into a container containing ethanolamine, heating the container for 3 to 6 hours, taking it out, washing it with water, and drying it to obtain the 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, in step (3), the photocatalyst is a catalyst that can be excited within the visible light wavelength range, and the amount of the photocatalyst used is 5 to 10 g / kg of hemp roving.

[0012] Furthermore, the photocatalyst is at least one of TiO2-CQDs, ZnO-CQDs, and ZnIn2S4.

[0013] In the above technical scheme, 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.

[0014] Furthermore, the illumination treatment time in step (3) is 10 to 60 hours.

[0015] 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.

[0016] Furthermore, in step (3), the solid bath ratio of the flax roving to the photocatalyst degumming solution is 1:10-100.

[0017] Furthermore, in step (3), the heating temperature is 80-100° C. and the heating time is 3-6 hours.

[0018] Furthermore, in step (3), the solid-to-liquid ratio of the hemp roving to ethanolamine is 1:15-20.

[0019] Furthermore, the mass concentration of ethanolamine in step (3) is 10-30%.

[0020] Furthermore, the hemp fiber is one of ramie, hemp, ramie, kenaf or jute.

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming, which utilizes photocatalyst and organic alkali to remove wax, pectin, lignin, hemicellulose and other colloid components in the linen roving, has a simple operation process, mild degumming conditions, good degumming effect, and little damage to the linen fiber. Moreover, the organic alkali can be recycled, less waste liquid is generated, and little pollution to the environment is caused. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing long linen yarn based on photocatalysis and alkali treatment 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.

[0024] Example 1

[0025] This embodiment provides a method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming, comprising the steps of:

[0026] (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;

[0027] (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;

[0028] (3) 500 ml of 10 g / L TiO2-CQDs was added to a 30 L glass reactor to prepare a degumming solution, and 1000 g of hemp roving was placed in the degumming solution for light treatment, water was added to make the solid-to-bath ratio of the hemp roving and the degumming mixed solution 1:20, and the mixture 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, and then the hemp roving was placed in a container containing ethanolamine solution, the mass concentration of the ethanolamine solution was 30%, and the solid-to-liquid ratio of the hemp roving to the ethanolamine solution was 1:20. After heating at 100 ° C for 4 hours, the mixture was taken out, washed with water, and dried to obtain degummed hemp roving;

[0029] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0030] Example 2

[0031] This embodiment provides a method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming, comprising the steps of:

[0032] (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;

[0033] (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;

[0034] (3) 700 ml of 10 g / L TiO2-CQDs suspension was added to a 30 L glass reactor to prepare a degumming solution, and 1000 g of hemp roving was placed in the degumming solution for light treatment, water was added to make the solid-bath ratio of the hemp roving and the degumming mixed solution 1:50, and the hemp roving was taken out after continuous light treatment with an LED lamp for 30 h, and washed and dried, and then the hemp roving was placed in a container containing an ethanolamine solution, the mass concentration of the ethanolamine solution was 30%, and the solid-liquid ratio of the hemp roving to the ethanolamine solution was 1:20. After heating at 90 ° C for 5 h, it was taken out, washed and dried to obtain degummed hemp roving;

[0035] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0036] Comparative Example 1

[0037] This comparative example provides a method for preparing long linen yarn by degumming using a photocatalyst, comprising the steps of:

[0038] (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;

[0039] (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;

[0040] (3) 500 ml of 10 g / L TiO2-CQDs suspension was added to a 30 L glass reactor to prepare a degumming solution, and 1000 g of hemp roving was placed in the degumming solution, water was added to make the solid bath ratio of the hemp roving and the degumming mixed solution 1:20, and the solution was treated in the dark for 4 days, and then the hemp roving was taken out and washed and dried to obtain degummed hemp roving;

[0041] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0042] Comparative Example 2

[0043] This comparative example provides a method for preparing long linen yarn by degumming using a photocatalyst, comprising the steps of:

[0044] (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;

[0045] (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;

[0046] (3) 500 ml of 10 g / L TiO2-CQDs suspension was added to a 30 L glass reactor to prepare a degumming solution, and 1000 g of hemp roving was placed in the degumming solution for light treatment, water was added to make the solid-bath ratio of the hemp roving and the degumming mixed solution 1:20, and the hemp roving was treated with sunlight for 4 days, specifically, the light treatment was 12 hours and then the dark treatment was 12 hours, and the treatment was repeated for 4 days, and then the hemp roving was taken out, washed with water, and dried to obtain degummed hemp roving;

[0047] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0048] Comparative Example 3

[0049] This comparative example provides a method for preparing long linen yarn by degumming using alkali treatment, comprising the steps of:

[0050] (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;

[0051] (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;

[0052] (3) placing the ramie roving into a 30L glass reactor, adding water, the solid-to-liquid ratio of the ramie roving to the solution being 1:20, and performing dark treatment for 4 days, then placing the ramie roving into a container containing an ethanolamine solution, the mass concentration of the ethanolamine solution being 30%, the solid-to-liquid ratio of the ramie roving to the ethanolamine solution being 1:20, heating the ramie roving at 100°C for 4h, taking it out, washing it with water, and drying it to obtain a degummed ramie roving;

[0053] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0054] Comparative Example 4

[0055] This comparative example provides a method for preparing long linen yarn by degumming using alkali treatment, comprising the steps of:

[0056] (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;

[0057] (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;

[0058] (3) Put the hemp roving into a 30L glass reactor, add water, the solid-to-liquid ratio of the hemp roving to the solution is 1:20, and treat it with sunlight for 4 days, specifically, treat it in the dark for 12 hours after treating it with light for 12 hours, repeat it for 4 days, and then put the hemp roving into a container containing ethanolamine solution, the mass concentration of the ethanolamine solution is 30%, the solid-to-liquid ratio of the hemp roving to the ethanolamine solution is 1:20, heat it at 100°C for 4 hours, take it out, wash it with water, and dry it to obtain degummed hemp roving;

[0059] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0060] Comparative Example 5

[0061] This comparative example provides a method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming, comprising the steps of:

[0062] (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;

[0063] (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;

[0064] (3) 500 ml of 10 g / L TiO2-CQDs suspension was added to a 30 L glass reactor to prepare a degumming solution, and 1000 g of hemp roving was placed in the degumming solution for light treatment, water was added to make the solid-bath ratio of the hemp roving and the degumming mixed solution 1:20, and the solution was treated in the dark for 4 days. After the treatment, the hemp roving was taken out, and then the hemp roving was placed in a container containing an ethanolamine solution, the mass concentration of the ethanolamine solution was 30%, and the solid-liquid ratio of the hemp roving to the ethanolamine solution was 1:20. After heating at 100 ° C for 4 h, the solution was taken out, washed with water, and dried to obtain degummed hemp roving;

[0065] (4) The degummed flax roving is passed through a water tank (with water, penetrant, softener, etc.) on a wet spinning frame and then stretched to split and thin the process fibers into finer fiber bundles. The yarn is then twisted into yarn, dried, and wound onto a bobbin to obtain the finished flax roving, i.e., long flax yarn.

[0066] The chemical composition test of the degummed long linen yarn 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 long linen yarn prepared in Comparative Example 4 and Example 1 was carried out, and the test results are shown in Table 2.

[0067] The above chemical composition test and physical property test methods are as follows:

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Table 1

[0072]

[0073] Table 2

[0074]

[0075] It can be seen from Table 1 above that Example 1 uses TiO2-CQDs + organic base to treat under light conditions, and the prepared long linen yarn has the highest removal rate of wax, pectin, lignin, hemicellulose and other colloids; Compared with Example 1, Comparative Example 5 is treated under dark conditions, and its pectin and lignin content is higher than that of Example 1; Comparative Examples 1 and 2 use TiO2-CQDs to treat under dark conditions or light, and the content of each colloid is still very high; Comparative Examples 3 and 4 use ethanolamine for dark treatment or light treatment, and part of the pectin, wax, lignin, hemicellulose, etc. are removed, but the content of pectin, lignin, hemicellulose, etc. is still very high.

[0076] It can be seen from Table 2 above that Example 1 adopts a TiO2-CQDs photocatalyst and an organic base combined degumming process. After degumming, the fiber fineness is 51 Nm, the breaking strength is 44 cN / dtex, and the yarn is uniform, indicating that the degumming effect is good, the colloid bonding between the single fibers is reduced, the hemp fiber fineness is finer, and the fiber has better dispersibility. In addition, the reaction conditions of this Example 1 are mild, and the damage to the hemp fiber is less, so that the long hemp yarn has better breaking strength and high breaking strength.

[0077] It should be noted that some parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0078] 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 by combined degumming based on photocatalysis and alkali treatment, 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 produce long flax strips with uniform structure and parallel straightness, which are then drawn, twisted and wound by a roving machine to obtain flax roving; (3) adding a photocatalyst into a glass reactor to prepare a degumming solution, and placing the hemp roving into the degumming solution for light treatment, taking out the hemp roving after the light treatment is completed, and then placing the hemp roving into a container containing ethanolamine, heating the container for 3 to 6 hours, taking it out, washing it with water, and drying it to obtain the 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 alkali treatment combined degumming according to claim 1 is characterized in that: The photocatalyst in step (3) is a catalyst that can be excited within the visible light wavelength range, and the amount of the photocatalyst used is 5 to 10 g / kg of hemp roving.

3. The method for preparing long linen yarn by combined degumming based on photocatalysis and alkali treatment according to claim 1, characterized in that: The illumination treatment time in step (3) is 10 to 60 hours.

4. The method for preparing long linen yarn by combined degumming based on photocatalysis and alkali treatment according to claim 1, characterized in that: 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.

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

6. The method for preparing long linen yarn by combined degumming based on photocatalysis and alkali treatment according to claim 1, characterized in that: In the step (3), the heating temperature is 80-100° C. and the heating time is 3-6 hours.

7. The method for preparing long linen yarn based on photocatalysis and alkali treatment combined degumming according to claim 1, characterized in that: In the step (3), the solid-to-liquid ratio of the flax roving to ethanolamine is 1:15-20.

8. A method for preparing flax yarn based on photocatalysis and alkali treatment combined degumming according to any one of claims 1 to 7, characterized in that: The hemp fiber is one of ramie, hemp, apocynum, kenaf or jute.

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