Manufacturing method of colored lyocell filaments
By adding dyes in the spinning raw liquid preparation stage and completing color fixation during the spinning process, the problem of low color fastness in the denim fabric dyeing process is solved, and the stable production of colored lyesel filaments and the preparation of high-value-added fabrics are achieved.
Patent Information
- Application Number
- CN202411931986.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-03-14
AI Technical Summary
The dyeing process of existing denim fabrics has problems such as low color fastness, limited resources and environmental pollution. Especially in the dyeing performance of Lycel fiber filaments is less studied, and it is difficult to obtain stable and colored filaments.
The dye is added during the preparation stage of the spinning stock solution and combined with the subsequent process, the color of the obtained color is more stable, and the color is fixed during the spinning process. The insoluble in indigo dye is adopted, combined with the dry spray wet spinning process of Lycel fiber, during the swelling stage of the pulp and solvent mixing, there is less water in the material, which will not affect the dyeing process of the indigo dye.
By adding dye to the spinning raw liquid and completing color fixation during the spinning process, the problem of low color fastness is solved, the added value of the fabric is improved, and the fabric is given a new style and consumption performance, while reducing the problem of color difference before and after the post-processing process and dyeing.
Smart Images
Figure CN119615400A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lyocell filament manufacturing, in particular to a method for manufacturing colored lyocell filament. Background Art
[0002] Denim clothing has experienced a long period of market baptism and is still enduring. By constantly updating and improving the processing technology, introducing popular fiber raw materials, and constantly innovating in color and style, more and more people can accept and fall in love with denim clothing, thus giving denim clothing a broader development prospect.
[0003] Conventional denim fabrics are produced by weaving first and then dyeing. Denim fabric dyeing is mainly divided into indigo dyeing, sulphur dyeing and reactive dyeing according to different dyes. The characteristics of the above three dyeing methods are as follows: 1. Indigo dyeing is used for the most traditional classic blue. Natural indigo can be extracted from plants such as indigo grass. The dyed blue is generally lighter, and the resources are limited and the yield is low. Synthetic indigo dye can dye darker colors, but it is more polluting to the environment; 2. Sulfur dyeing is the most commonly used dyeing method for denim fabrics, but it has the disadvantage of poor storage stability; 3. Reactive dyeing is mainly used for colored denim fabrics, and has high washing and soaping fastness. However, when dyeing denim fabrics with reactive dyes, the utilization rate of dyes is low and a large amount of colored wastewater will be generated.
[0004] Market demand has brought about industrial upgrading. Lyocell fiber, also known as Tencel, is a man-made environmentally friendly fiber made from natural wood and bamboo. Colored Lyocell filaments are now introduced into the denim weaving process.
[0005] Under different equipment and process conditions, two completely different products, staple fiber and filament fiber, can be obtained. At present, there are relatively few studies on the dyeing performance of lyocell filaments in the market, and most of the research directions are still concentrated on the research of lyocell staple fibers and viscose fibers that have completed large-scale production. Due to the characteristics of the process flow and solvent, unlike lyocell staple fibers, it is not recommended to introduce metal ions and too many auxiliary materials in the production process of lyocell filaments, because metal ions will react with the solvent NMMO to release heat, which will seriously affect the stability of the lyocell fiber spinning solution, and too many auxiliary materials will affect the cellulose filamentation process, thereby affecting the physical properties of lyocell filament fibers, and even making it impossible to obtain filaments. In the research on improving the production process of lyocell filaments, our company has carried out corresponding development and research on various problems in the dyeing process and the broader colored filament market. Summary of the invention
[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a method for manufacturing colored lyocell filaments, which solves the problem of low color fastness caused by the existing method of weaving first and then dyeing.
[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a method for manufacturing colored lyocell filaments,
[0008] S1. The pulp is crushed in a crushing device to obtain a processed dry pulp;
[0009] S2. Add the treated dry pulp, 72-76% by mass of NMMO solvent, stabilizer and dye to the mixing and swelling device, and mix thoroughly under the action of a stirring paddle to obtain a porridge;
[0010] S3. The mixed and swollen porridge is sent to the dissolution device through a delivery pump, and vacuum and heating are performed in the device. The porridge is dehydrated in the device. As the concentration of NMMO solvent is further increased, the solubility of the solvent is further improved, and the cellulose and dye are dissolved in the solvent to form a spinning solution;
[0011] S4. Filtering the spinning solution using a filtering device to remove a small amount of impurities in the spinning solution;
[0012] S5. The impurity-removed spinning solution is delivered to the spinning box through a delivery pump, and after being spun and side-blown, it enters a coagulation bath and is cooled to form a tow, and the tow is continuously drawn and washed to remove the remaining NMMO component to form cellulose filaments;
[0013] S6. The cellulose filaments are subjected to oiling, drying and winding processes to obtain colored lyocell fiber filaments.
[0014] By adopting the above technical solution, the dye is added into the spinning solution preparation stage, and the obtained colored spinning solution is more stable in coordination with the subsequent process. The color is fixed during the spinning process, and the colored filaments are produced and then spun and woven. This can improve the color of the fabric surface, increase the added value of the fabric, and give the fabric a new style and wearing performance.
[0015] Furthermore, the pulverizing equipment, mixing and swelling equipment, dissolving equipment, filtering equipment, spinning box, and continuous drawing and washing equipment are connected through a delivery pump to form a continuous equipment.
[0016] By adopting the above technical solution, uninterrupted production process is one of the necessary conditions for obtaining filament fibers.
[0017] Furthermore, the dry pulp, solvent NMMO, stabilizer and dye in S2 are respectively added into the mixing swelling device at a fixed flow rate through continuous metering equipment, according to the ratio of pulp to NMMO solvent of 1:11-12, the amount of stabilizer added is 0.3-0.8% of the weight of the solvent, and the amount of dye added is 2-6% of the cellulose content. The mass fraction of NMMO solvent is 72-76%.
[0018] The adoption of the above technical solution is conducive to the continuous production of filaments and ensures the stability of the filaments.
[0019] Furthermore, in S2, the dye is indigo.
[0020] By adopting the above technical solution, indigo is directly applied to the production of colored lyocell filaments, and the produced colored filaments are used in the production of denim. Colored fabrics can be produced by using less indigo dye, thereby solving the problem of limited indigo resources and generally lighter blue color in the traditional method of spinning and weaving before dyeing.
[0021] Furthermore, in S2, the stabilizer is one of propylene glycol alginate, polyoxypropylene polyoxyethylene glycerol ether, and hydroxylamine.
[0022] Furthermore, the NMMO solvent used in S2 is a concentrated solvent after recycling, and the internal temperature of the swelling and mixing equipment is 85 to 95°C.
[0023] Furthermore, in S3, the dissolving equipment is a vertical dissolving machine, the internal heating temperature of the dissolving machine is 98-115°C, and the internal vacuum degree is -97.5 to -98.5 kPa.
[0024] Furthermore, in S4, the filtering accuracy of the filtering device is 10-20 μm.
[0025] By adopting the above technical solution, impurities in the spinning solution can be effectively removed.
[0026] Furthermore, in S5, the coagulation bath NMMO concentration is 8-12%, the temperature is 15-20°C, and the coagulation bath water and the washing water are reused through a recycling device.
[0027] By adopting the above technical solution, energy saving and environmental protection are achieved.
[0028] Furthermore, in S6, the oil used for oiling is made of the following raw materials in percentage by mass: water 92%-97%; smoothing agent 1%-5%; emulsifier 1%-2%; antistatic agent 0.5%-1%; softener 0%-1%. This oil is specially used for lyocell filaments. The spinning oil after water-based dispersion can greatly reduce the influence of the fiber's own water content on the oil, and adheres to the lyocell fiber, with faster adhesion speed and more uniform oiling.
[0029] Compared with the prior art, the advantages of the present invention are: 1. Different from the conventional process of weaving first and then dyeing, the dye is added into the lyocell filament spinning solution preparation stage to obtain a stable colored spinning solution, and the color fixation is completed during the spinning process; 2. Introducing colored lyocell filaments into the denim weaving process can improve the color of the fabric surface, increase the added value of the fabric, and give the fabric a new style and wearing performance. Colored lyocell filaments have natural advantages in weaving and can adapt well to various weaving methods including knitting and weaving. At the same time, the post-processing procedures of the cloth (such as cloth dyeing, washing and color fixation) are greatly reduced, and the color difference between the front and back, the step difference (color fading difference), the color fastness difference, the color difference between the edge and the like in the cloth dyeing are effectively reduced; 3. Lyocell filament fibers have good strength, comfort and unique touch. In addition, they also have good dyeing performance and have With the advantages of being biodegradable and green, it is widely used in the fields of non-woven fabrics, clothing and home textiles. 4. The study utilized the insoluble nature of indigo dye, combined with the dry-jet wet spinning process of lyocell fiber. During the swelling stage of the pulp and solvent mixture, there is a small amount of water in the material, which will not affect the dyeing process of indigo dye. A smaller dose of dye is used to obtain the target color fabric. At the same time, the higher concentration of NMMO solvent is alkaline, which dissolves both cellulose molecules and indigo dye during the swelling and dissolution process. In the subsequent spinning process, the coagulation bath and washing process remove the NMMO in the filaments, and the water-insoluble cellulose and indigo dye are perfectly combined at the microscopic level through molecular hydrogen bonds in this process, forming a stable and uniform colored lyocell filament. At the same time, the insoluble nature of indigo dye also ensures that the recycled NMMO solvent does not contain any excess components. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION
[0031] The present invention is further described in detail below with reference to the accompanying drawings.
[0032] Embodiment 1: Figure 1 A method for manufacturing colored lyocell filaments is provided, comprising a continuous crushing device, a mixing and swelling device, a dissolving device, a filtering device, a spinning box and a continuous drawing and washing device, wherein the devices are connected by a delivery pump to continuously produce lyocell filaments;
[0033] S1. The pulp is crushed in a crushing device to obtain a processed dry pulp;
[0034] S2. Add the treated dry pulp, NMMO solvent, stabilizer and dye to a mixed swelling device with an internal temperature between 85 and 95° C., wherein the mass fraction of NMMO solvent is 72-76%, and the dry pulp, NMMO solvent, stabilizer and dye are respectively added to the mixed swelling device continuously through a metering device according to the ratio of pulp to NMMO solvent of 1:11-12, the stabilizer is added in an amount of 0.3-0.8% by weight of the solvent, and the dye is added in an amount of cellulose content of 2-6%. The mixture is fully mixed under the action of a stirring paddle to obtain a pulp porridge;
[0035] S3. The mixed and swollen porridge is sent to the dissolving device through a delivery pump. The dissolving device is a vertical dissolving machine, and vacuum and heating are performed in the device. The internal heating temperature of the dissolving machine is 98-115°C, and the internal vacuum degree is -97.5 to -98.5kpa. The porridge is dehydrated in the device. As the concentration of NMMO solvent is further increased, the solubility of the solvent is further improved, and the cellulose and dye are dissolved in the solvent to form a spinning solution;
[0036] S4. Use a filtering device to filter the spinning solution to remove a small amount of impurities in the spinning solution. The filtering accuracy of the filtering device is 10-20 μm;
[0037] S5. The impurity-removed spinning solution is delivered to the spinning box through a delivery pump, and after being spun and blown sideways, it enters a coagulation bath and is cooled to form a tow. The tow passes through a continuous drawing and washing device to remove the remaining NMMO component to form cellulose filaments. In S5, the NMMO concentration of the coagulation bath is 8-12%, the temperature is 15-20°C, and the coagulation bath water and the washing water are reused through a recycling device.
[0038] S6. The cellulose filaments are subjected to the processes of oiling, drying and winding to obtain colored lyocell fiber filaments. The oil used for oiling is made of the following raw materials in the following mass percentages: water 92%-97%; smoothing agent 1%-5%; emulsifier 1%-2%; antistatic agent 0.5%-1%; softener 0%-1%, which is specially used for lyocell filaments.
[0039] On the basis of the above embodiment, the specific method of continuously adding into the mixed swelling equipment in S2 is: the dry pulp, solvent NMMO, stabilizer and dye are respectively delivered to the mixed swelling tank at a fixed flow rate through a metering delivery pump based on the metering of the metering equipment, and a discharge pump is arranged at the lower end of the mixed swelling tank to pump out the mixed swelling material at a fixed flow rate, thereby forming continuous production.
[0040] The above-mentioned measuring equipment can be a belt scale or a loss-in-weight scale.
[0041] The metering delivery pump can be a gear pump, a plunger pump or other pumps capable of controlling flow rate.
[0042] On the basis of the above embodiment, the NMMO solvent used in S2 is a solvent that is concentrated after recycling, the dye is indigo, and the stabilizer is one of propylene glycol alginate, polyoxypropylene polyoxyethylene glycerol ether, and hydroxylamine.
[0043] Example 2, on the basis of Example 1, a dark blue spinning solution is prepared according to the ratio of pulp to NMMO solvent of 1:12, the amount of stabilizer added is 0.5% of the weight of the solvent, and the amount of dye added is 3% of the cellulose content. The dynamic viscosity of the solution is about 1.3 million cp to 1.5 million cp, and the solution is filtered through a filter to remove impurities, and then spun through a spinning box, and enters a coagulation bath with a mass concentration of 11% at a spinning speed of 150m / min to complete cooling and coagulation molding, and is drawn through a treatment roller and washed with a multi-pass washing machine to wash the remaining NMMO solvent, and the filaments are oiled through an oiling device, and finally the excess water is removed through a dryer, and finally 1kg / roll of colored lyocell filaments that can be used for denim weaving is obtained through a filament winding machine. The color of the obtained filaments is dark blue, and physical testing shows that the filament properties are no significantly different from those of normal colorless lyocell fibers.
[0044] Comparative Example 1: According to the ratio of pulp to NMMO solvent of 1:12, the amount of stabilizer added is 0.5% of the weight of the solvent, and no dye is added to prepare the original color spinning solution. The dynamic viscosity of the solution is about 1.3 million cp to 1.5 million cp. It is filtered through a filter to remove impurities, and then spun through a spinning box. The spinning speed is 150m / min and enters a coagulation bath with a mass concentration of 11% to complete cooling and coagulation. After treatment roller drawing and multi-pass washing machine washing to clean the remaining NMMO solvent, the filaments are oiled by an oiling device, and finally the filaments are The dryer removes excess water, and finally the filament winding machine obtains 1kg / roll of primary color lyocell filaments, which are white with a yellowish tint. The dye with a cellulose content of 3% is added to dye the primary color lyocell filament textile fabric, and the color saturation of the obtained fabric is inferior to that of the fabric in Example 2, that is, the same dose of indigo dye is used, and the dye is added in the preparation stage of the filament spinning stock solution, and the color effect of producing colored filaments first and then using the colored filaments to weave fabrics is better than the effect of weaving fabrics first and then dyeing the fabrics.
[0045] Comparative Example 2: According to the ratio of pulp to NMMO solvent of 1:12, the amount of stabilizer added is 0.5% of the weight of the solvent, and the amount of dye added is 1% of the cellulose content, to prepare a light blue spinning solution with a dynamic viscosity of about 1.3 million cp to 1.5 million cp. The solution is filtered through a filter to remove impurities, and then spun through a spinning box, and enters a coagulation bath with a mass concentration of 10% at a spinning speed of 150m / min to complete cooling and coagulation molding. The remaining NMMO solvent is washed by a treatment roller and a multi-pass washing machine, and the filaments are oiled by an oiling device, and finally the excess water is removed by a dryer. Finally, 1kg / roll of colored lyocell filaments that can be used for denim weaving is obtained through a filament winding machine. The color of the obtained filaments is light blue, and physical testing shows that there is no obvious difference between the filament properties and normal colorless lyocell fibers.
[0046] Although the preferred embodiments of the present invention are described in detail above, it should be clearly understood that various modifications and variations are possible for those skilled in the art. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for producing colored lyocell filaments, characterized in that: S1. The pulp is crushed in a crushing device to obtain a processed dry pulp; S2. Add the treated dry pulp, NMMO solvent, stabilizer and dye to the mixed swelling device and mix thoroughly under the action of a stirring paddle to obtain a porridge; S3. The mixed and swollen porridge is sent to the dissolution device through a delivery pump, and vacuum and heating are performed in the device. The porridge is dehydrated in the device. As the concentration of NMMO solvent is further increased, the solubility of the solvent is further improved, and the cellulose and dye are dissolved in the solvent to form a spinning solution; S4. Filtering the spinning solution using a filtering device to remove a small amount of impurities in the spinning solution; S5. The impurity-removed spinning solution is delivered to the spinning box through a delivery pump, and after being spun and side-blown, it enters a coagulation bath and is cooled to form a tow, and the tow is continuously drawn and washed to remove the remaining NMMO component to form cellulose filaments; S6. The cellulose filaments are subjected to oiling, drying and winding processes to obtain colored lyocell fiber filaments.
2. The method for producing colored lyocell filaments according to claim 1, characterized in that: The crushing equipment, mixing and swelling equipment, dissolving equipment, filtering equipment, spinning box, and continuous drawing and washing equipment are connected through a delivery pump to form a continuous equipment to ensure the uninterrupted production of filament fibers.
3. The method for producing colored lyocell filaments according to claim 1, characterized in that: In S2, dry pulp, solvent NMMO, stabilizer and dye are respectively added into the mixing swelling device at a fixed flow rate through continuous metering equipment according to the ratio of pulp to NMMO solvent of 1:11-12, the amount of stabilizer added is 0.3-0.8% of the weight of the solvent, and the amount of dye added is 2-6% of the cellulose content. The mass fraction of NMMO solvent is 72-76%.
4. The method for producing colored lyocell filaments according to claim 1, characterized in that: The dye in S2 is indigo.
5. The method for producing colored lyocell filaments according to claim 1, characterized in that: The stabilizer in S2 is one of propylene glycol alginate, polyoxypropylene polyoxyethylene glycerol ether, and hydroxylamine.
6. The method for producing colored lyocell filaments according to claim 1, characterized in that: The internal temperature of the swelling and mixing equipment in S2 was 85 to 95°C.
7. The method for producing colored lyocell filaments according to claim 1, characterized in that: The dissolving equipment in S3 is a vertical dissolving machine, the internal heating temperature of the dissolving machine is 98-115°C, and the internal vacuum degree is -97.5 to -98.5kpa.
8. The method for producing colored lyocell filaments according to claim 1, characterized in that: The filtration accuracy of the filtration equipment in S4 is 10-20μm.
9. The method for producing colored lyocell filaments according to claim 1, characterized in that: The NMMO concentration of the coagulation bath in S5 is 8-12%, the temperature is 15-20°C, and the coagulation bath water and the washing water are reused through a recycling device.
10. The method for producing colored lyocell filaments according to claim 1, characterized in that: The oil used in oiling S6 is made of the following raw materials in mass percentage: water 92%-97%; smoothing agent 1%-5%; emulsifier 1%-2%; antistatic agent 0.5%-1%; softener 0%-1%.