Preparation method of composite ramie fabric
By pretreating and carbonizing ramie fibers at low temperatures to form a porous structure and oxygen-containing functional groups, and combining this with a phase change material loading process, the problem of easy shedding of phase change materials is solved, thereby improving the thermal conductivity and temperature regulation effect of the fabric.
Patent Information
- Application Number
- CN202511024455.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-11-07
AI Technical Summary
Existing temperature-regulating fabrics are prone to phase change material shedding after repeated washing, affecting the temperature-regulating effect of the fabric and resulting in a poor hand feel.
By pretreating and low-temperature carbonizing ramie fibers to form a porous structure and oxygen-containing functional groups, and combining this with a phase change material loading process, composite ramie fabrics are prepared.
It improves the compatibility between ramie fiber and phase change material, prevents leakage of phase change material, enhances the thermal conductivity and temperature regulation effect of the fabric, and maintains the tensile strength and production efficiency of the fiber.
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Figure CN120905948A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of new materials, and particularly relates to a preparation method of a composite ramie fabric. BACKGROUND
[0002] Ramie fiber has the functions of bacteriostasis, air permeability, coolness, corrosion resistance, mildew resistance and sweat absorption, and its moisture permeability is about 3-5 times that of cotton fiber, and it is recognized as the "king of natural fibers" in the world. With the development of high value-added fabrics, the dynamic temperature regulating composite ramie fabric developed by using phase change materials can absorb or release heat when the environmental temperature changes, and keep a comfortable microclimate, so it has been widely used.
[0003] At present, the fabric with temperature regulating function generally has a layer of heat-sensitive phase change material attached to the surface of the fabric. Such temperature regulating fabric has poor hand feeling, and the phase change material is easy to fall off after being washed for many times, which affects the temperature regulating effect of the fabric.
[0004] Based on the above technical problems, the present application provides a preparation method of a composite ramie fabric. SUMMARY
[0005] The purpose of the present application is to solve the technical problems mentioned in the background art, and the purpose of the present application is achieved by the following technical scheme: A preparation method of a composite ramie fabric, comprising the following steps: Step S1, pretreating ramie fibers; Step S2, surface carbonization treatment of the pretreated ramie fibers; The surface carbonization treatment comprises: Step S21, low-temperature carbonization of the ramie fibers obtained in step S1 in an inert gas, the carbonization temperature is 250-400 DEG C, the carbonization time is 30-120 min, and the heating rate to the carbonization temperature is 2-5 DEG C / min; Step S22, ultrasonic cleaning of the low-temperature carbonized ramie fibers, and drying; Step S3, twisting the ramie fibers after surface carbonization treatment and low-melting-point fibers into ramie yarns; Step S4, loading phase change materials on the ramie yarns; Step S5, weaving the ramie yarns after loading the phase change materials into a fabric.
[0006] Further, the pretreatment process in step S1 comprises: Step S11, immersing the ramie fibers in a sodium hydroxide solution and treating at 95-100 DEG C for 1-2 h; Step S12, rinsing the ramie fibers obtained in step S11 in clean water; Step S13, drying the ramie fiber obtained in step S12 at 60-80℃ until constant weight.
[0007] Further, the ramie fiber is also immersed in a phosphoric acid solution before step S13, the concentration of the phosphoric acid solution is 4-6 wt%, and the immersion time is 30-60min.
[0008] Further, the inert gas is nitrogen, and the flow rate of the nitrogen is 50-200mL / min.
[0009] Further, the loading process of the phase change material includes: Step S41, preparing a phase change material melt; Step S42, preheating the ramie yarn in a reaction kettle to 60-80℃, and vacuumizing to 0.1-0.5kPa; Step S43, injecting the phase change material melt into the reaction kettle, and vacuumizing to 0.5-1kPa; Step S44, slowly releasing the vacuum to normal pressure, and maintaining 60-80℃ for 60-180min of immersion; Step S45, removing the excess phase change material melt on the surface of the ramie yarn, and heat treating the ramie yarn.
[0010] Further, the phase change material is paraffin or fatty acid.
[0011] Further, the excess phase change material melt is removed by a precision roller or a centrifuge.
[0012] Further, the loading process of the phase change material includes: Step S41', preparing a phase change material solution, and heating to 25-70℃; Step S42', immersing the ramie yarn in the phase change material solution, and vacuumizing to 0.1-0.5kPa; Step S43', slowly releasing the vacuum to normal pressure, and maintaining 25-70℃ for 60-120min of immersion; Step S44', drying at 25-80℃ for 3-5h, and heat treating the ramie yarn.
[0013] Further, the phase change material is polyethylene glycol.
[0014] The technical scheme provided by the embodiments of the present application has at least the following technical effects or advantages: 1. By performing surface carbonization treatment on the ramie fiber, the inner core of the ramie fiber maintains the morphology of natural fibers, ensuring the tensile performance of the ramie fiber; at the same time, a rich porous structure is formed on the surface of the ramie fiber, providing a stable support framework for the phase change material; 2. By low-temperature surface carbonization of ramie fibers, abundant oxygen-containing functional groups can be formed on the surface of the ramie fibers, improving the compatibility of the ramie fibers with the phase change material and effectively preventing leakage of the phase change material; 3. By surface carbonization of the ramie fibers, the thermal conductivity between the ramie fibers is improved, and the temperature regulating effect of the fabric is increased. BRIEF DESCRIPTION OF DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0016] Figure 1 Performance indicators of the ramie fibers prepared in Example 1 of the present application; Figure 2 Performance indicators of the ramie fibers prepared in Example 2 of the present application; Figure 3 Performance indicators of the ramie fibers prepared in Example 3 of the present application; Figure 4 Performance indicators of the ramie fibers prepared in Comparative Example 1 of the present application; Figure 5 Performance indicators of the ramie fibers prepared in Comparative Example 2 of the present application; Figure 6 Performance indicators of the ramie fibers prepared in Comparative Example 3 of the present application; Figure 7 Performance indicators of the ramie fibers prepared in Comparative Example 3 of the present application; DETAILED DESCRIPTION
[0017] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined application purposes, the specific embodiments, structures, features and effects according to the present application will be described in detail below with reference to the drawings and preferred embodiments.
[0018] A preparation method of a composite ramie fabric, comprising the following steps: Step S1, pretreating the ramie fibers; The pretreatment process comprises: Step S11, immersing the ramie fibers in a sodium hydroxide solution with a concentration of 8 g / L, and heating to 95-100℃ for 1-2 h; Step S12, immersing the ramie fibers treated with the sodium hydroxide solution in clean water for rinsing to remove residual sodium hydroxide and reaction impurities; Step S13, dry the rinsed ramie fibers at 60-80℃ until constant weight.
[0019] By pretreating the ramie fibers with sodium hydroxide solution, the residual lignin, hemicellulose and pectin and other impurities can be further removed, and purer ramie fibers can be obtained.
[0020] Preferably, the ramie fibers are immersed in a phosphoric acid solution with a concentration of 4-6 wt% before step S13, and the immersion time is 30-60 min. Since phosphoric acid reacts preferentially with hemicellulose / lignin, on the one hand, the carbonization temperature can be reduced, saving energy; on the other hand, the damage to cellulose can be reduced, and the tensile strength of the ramie fibers can be improved.
[0021] Step S2, surface carbonization treatment is performed on the pretreated ramie fibers; The surface carbonization treatment includes: Step S21, the pretreated ramie fibers are added to the carbonization furnace, heated to 250-400℃ at a heating rate of 2-5℃ / min, nitrogen gas is introduced into the carbonization furnace, and the flow rate of the nitrogen gas is controlled at 50-200 mL / min, low-temperature carbonization is performed for 30-120 min, and then the temperature is naturally cooled to room temperature under nitrogen atmosphere.
[0022] Ramie fibers are mainly composed of cellulose, hemicellulose and lignin, hemicellulose begins to decompose significantly at 200-300℃, cellulose pyrolyzes at 300-400℃, and lignin pyrolyzes at 250-500℃. By controlling the temperature in the range of 250-400℃, the surface of the ramie fibers can be carbonized preferentially, while the internal structure remains relatively intact.
[0023] By heating the ramie fibers at a lower heating rate, the intense pyrolysis of the ramie fibers can be avoided, and the uniformity of the surface carbon layer can be improved. By carbonizing under nitrogen atmosphere, on the one hand, the oxidative degradation of the ramie fibers at high temperature can be prevented, and on the other hand, the volatile products generated by pyrolysis can be removed.
[0024] By surface carbonization treatment of the ramie fibers, the inner core of the ramie fibers maintains the morphology of natural fibers, ensuring the tensile properties of the ramie fibers; at the same time, a rich porous structure is formed on the surface of the ramie fibers, providing a stable support framework for the phase change material; by low-temperature surface carbonization of the ramie fibers, a rich oxygen-containing functional group can be formed on the surface of the ramie fibers, improving the compatibility of the ramie fibers with the phase change material, and effectively preventing the leakage of the phase change material; by surface carbonization of the ramie fibers, the thermal conductivity between the ramie fibers is improved, and the temperature regulating effect of the fabric is increased.
[0025] Step S22, ultrasonic cleaning of the low-temperature carbonized ramie fibers to remove the loose carbon structure on the surface of the ramie fibers, and drying.
[0026] Step S3, twisting the ramie fibers after surface carbonization treatment into ramie yarns; preferably, the ramie fibers are blended with low-melting-point fibers by composite spinning technology, and the low-melting-point fibers can be PET fibers.
[0027] Step S4, loading a phase change material on the ramie yarns; If the phase change material is a material with good thermal stability such as paraffin or fatty acid, the loading process of the phase change material includes: Step S41, preparing a phase change material melt; taking paraffin as an example, the paraffin is placed in a stainless steel heating kettle, heated to 70°C, and stirred at a constant temperature of 300 rpm for 30 minutes to ensure complete melting.
[0028] Step S42, preheating the ramie yarns in the reaction kettle to 70°C, and vacuumizing to 0.1-0.5 kPa; to remove air in the ramie yarns.
[0029] Step S43, injecting the paraffin melt into the reaction kettle, so that the liquid level of the paraffin melt is higher than the ramie yarns by more than 10 cm, and vacuumizing to 0.5-1 kPa, so that the paraffin melt enters the carbon layer of the ramie fibers.
[0030] Step S44, slowly releasing the vacuum to normal pressure, and maintaining 60-80°C for 60-180 min of immersion; Step S45, removing the excess phase change material melt on the surface of the ramie yarns by precision rollers or centrifuges.
[0031] If the phase change material is soluble polyethylene glycol, the loading process of the phase change material includes: Step S41', preparing a phase change material solution and heating to 25-70°C; specifically, the polyethylene glycol is added to a solution prepared by mixing water and ethanol in a volume ratio of 7:3, heated to 70°C, and dissolved by magnetic stirring or ultrasonic assistance.
[0032] Step S42', immersing the ramie yarns in the phase change material solution, vacuumizing to 0.1-0.5 kPa, and maintaining for 5 min; Step S43', slowly releasing the vacuum to normal pressure, and maintaining 70°C for 60-120 min of immersion; Step S44', taking out the immersed ramie yarns from the phase change material solution, and drying at 25-80°C for 3-5 h.
[0033] After the loading of the phase change material is completed, the ramie yarn is subjected to heat treatment. The heat treatment can partially melt the low-melting-point fibers to form inter-fiber bonding, which can reduce the hairiness of the ramie yarn and improve the tensile strength of the ramie yarn, and also improve the smoothness of the surface of the ramie yarn, so that the ramie yarn can meet the requirements of high-speed weaving without sizing, and the production efficiency of the ramie fabric is improved. In addition, the low-melting-point fibers can also encapsulate the ramie fibers, further avoiding leakage of the phase change material.
[0034] Step S5, weaving the ramie yarn loaded with the phase change material into a fabric.
[0035] Example 1 Step S1, pretreatment of the ramie fibers S11, immersing the ramie fibers in a sodium hydroxide solution with a concentration of 8 g / L, heating to 95℃ for 1.5 h; S12, immersing the ramie fibers treated with the sodium hydroxide solution in clean water for rinsing to remove residual sodium hydroxide and reaction impurities; S13, immersing the rinsed ramie fibers in a phosphoric acid solution with a concentration of 5 wt% for 45 min, and then placing them in an oven for drying at 70℃ until a constant weight is reached. Step S2, surface carbonization treatment of the pretreated ramie fibers S21, adding the pretreated ramie fibers to a carbonization furnace, heating to 300℃ at a heating rate of 3℃ / min, introducing nitrogen gas into the carbonization furnace at a flow rate of 150 mL / min, low-temperature carbonization for 60 min, and then naturally cooling to room temperature under a nitrogen atmosphere.
[0036] S22, ultrasonic cleaning of the low-temperature carbonized ramie fibers to remove loose carbon structures on the surface of the ramie fibers, and drying.
[0037] Step S3, twisting the ramie fibers treated with surface carbonization and PET low-melting-point fibers in a ratio of 70:30 into ramie yarns; Step S4, loading the phase change material on the ramie yarns Step S41, preparing a phase change material melt; taking paraffin as an example, placing the paraffin in a stainless steel heating kettle, heating to 70℃, and stirring at a constant temperature for 30 minutes at a speed of 300 rpm to ensure complete melting.
[0038] Step S42, preheating the ramie yarns in a reaction kettle to 70℃, and vacuuming to 0.3 kPa to remove air in the ramie yarns.
[0039] Step S43, injecting the paraffin melt into the reaction kettle, so that the liquid level of the paraffin melt is higher than the ramie yarns by more than 10 cm, vacuuming to 0.8 kPa, and making the paraffin melt enter the carbon layer of the ramie fibers.
[0040] Step S44, slowly release the vacuum to normal pressure, keep 70℃ for 120min; Step S45, remove the excess phase change material melt on the surface of the ramie yarn by precision roller.
[0041] 5. The ramie yarn loaded with phase change material is woven into fabric by plain weave process. The performance index of the ramie fiber prepared in Example 1 is shown in Figure 1 .
[0042] Example 2 The concentration of phosphoric acid in step S13 of Example 1 is changed to 4wt%, and the immersion time is changed to 60min; the carbonization temperature in step S21 is changed to 250℃, and the carbonization time is changed to 90min, and the others are the same as Example 1.
[0043] The performance index of the ramie fiber prepared in Example 2 is shown in Figure 2 It can be seen that reducing the concentration of phosphoric acid and the carbonization temperature will lead to insufficient modification of the fiber, and the loading rate and strength decrease slightly.
[0044] Example 3 Step S1, pretreatment of ramie fiber S11, immerse the ramie fiber in a sodium hydroxide solution with a concentration of 8g / L, heat to 95℃ for 1.5h; S12, immerse the ramie fiber treated with sodium hydroxide solution in clean water for rinsing to remove residual sodium hydroxide and reaction impurities; S13, dry the rinsed ramie fiber in an oven at 70℃ to constant weight. Step S2, surface carbonization treatment of the pretreated ramie fiber; S21, add the pretreated ramie fiber to the carbonization furnace, heat to 400℃ at a heating rate of 3℃ / min, introduce nitrogen into the carbonization furnace, control the flow rate of nitrogen to be 200mL / min, low-temperature carbonize for 40min, and then naturally cool to room temperature in nitrogen atmosphere.
[0045] S22, ultrasonic cleaning of the low-temperature carbonized ramie fiber to remove the loose carbon structure on the surface of the ramie fiber, and dry.
[0046] Step S3, twist the ramie fiber after surface carbonization treatment and PET low-melting-point fiber into ramie yarn at a ratio of 70:30; Step S4, load phase change material on the ramie yarn; Step S41', prepare the phase change material solution and heat to 60°C; specifically, add polyethylene glycol to a solution prepared by mixing water and ethanol in a volume ratio of 7:3, heat to 70°C, and dissolve by magnetic stirring or ultrasonic assistance.
[0047] Step S42', immerse the ramie yarn in the phase change material solution, vacuumize to 0.3 kPa, and maintain for 5 min; Step S43', slowly release the vacuum to normal pressure, maintain the 70°C immersion for 80 min; Step S44', take out the immersed ramie yarn from the phase change material solution and dry at 60°C for 4 h.
[0048] 5. Weave the phase change material loaded ramie yarn into a fabric by plain weave process.
[0049] The performance indicators of the ramie fibers prepared in Example 3 are shown in Table 3. Figure 3 As shown in Table 3, after canceling the phosphoric acid immersion, the cellulose is damaged due to high temperature carbonization without phosphoric acid protection, resulting in a significant decrease in tensile strength of the fabric; at the same time, the relatively large molecular weight of polyethylene glycol reduces the penetration efficiency, resulting in a decrease in phase change material loading rate.
[0050] Comparative Example 1 Compared with Example 1, the pretreatment process of steps S11-S13 is omitted, and the rest is the same as Example 1.
[0051] The performance indicators of the ramie fibers prepared in Comparative Example 1 are shown in Table 2. Figure 4 As shown in Table 2, the uneven carbonization caused by the absence of hemicellulose / lignin leads to a fragile fiber structure after carbonization, and the loading rate is extremely low.
[0052] Comparative Example 2 Compared with Example 1, the phosphoric acid immersion treatment process in step S13 is omitted, and the rest is the same as Example 1.
[0053] The performance indicators of the ramie fibers prepared in Comparative Example 2 are shown in Table 3. Figure 5 As shown in Table 3, the lack of preferential reaction of phosphoric acid on hemicellulose results in damage to cellulose during carbonization, and the strength / loading rate is lower than that of Example 1.
[0054] Comparative Example 3 Compared with Example 1, the surface carbonization process of step S2 is omitted, and the rest is the same as Example 1.
[0055] The performance indicators of the ramie fibers prepared in Comparative Example 3 are shown in Table 3. Figure 6 As shown in Table 3, the absence of carbonization layer leads to a lack of porous structure in the fiber, and the paraffin only adheres to the surface, resulting in a significant decrease in loading rate and enthalpy.
[0056] As shown in Table 3, the absence of carbonization layer leads to a lack of porous structure in the fiber, and the paraffin only adheres to the surface, resulting in a significant decrease in loading rate and enthalpy. Figure 7The performance comparison summary table of the examples and the comparative examples is shown. It can be seen that: 1. The tensile strength can be increased by more than 15% by phosphoric acid impregnation treatment, and the cellulose structure is protected; 2. The carbon layer generation and fiber integrity can be balanced by carbonization at 300°C, and the loading rate is increased by 130% compared with the non-carbonization group.
[0057] 3. Compared with polyethylene glycol, paraffin has lower viscosity, so it is easier to penetrate into the carbon layer, and the enthalpy value is 25% higher than that of polyethylene glycol under the same conditions. The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application shall still fall within the scope of the technical solution of the present application.
Claims
1. A method for preparing a composite ramie fabric, characterized in that, The method comprises the following steps: Step S1, pretreating the ramie fibers; Step S2, performing surface carbonization treatment on the pretreated ramie fibers; The surface carbonization treatment comprises: Step S21, carbonizing the ramie fibers obtained in step S1 at a low temperature in an inert gas, the carbonization temperature being 250-400℃, the carbonization time being 30-120min, and the heating rate to the carbonization temperature being 2-5℃ / min; Step S22, performing ultrasonic cleaning on the ramie fibers after the low-temperature carbonization and drying; Step S3, twisting the ramie fibers after the surface carbonization treatment with low-melting-point fibers to form ramie yarns; Step S4, loading phase change materials on the ramie yarns; Step S5, weaving the ramie yarns after the loading of the phase change materials into a fabric.
2. A method of preparing a composite ramie fabric according to claim 1, characterized in that, The pretreatment process in step S1 comprises: Step S11, immersing the ramie fibers in a sodium hydroxide solution and treating at 95-100℃ for 1-2h; Step S12, immersing the ramie fibers obtained in step S11 in clean water for rinsing; Step S13, drying the ramie fibers obtained in step S12 at 60-80℃ to a constant weight.
3. A method of preparing a composite ramie fabric as claimed in claim 2, wherein, Before step S13, the ramie fibers are also immersed in a phosphoric acid solution, the concentration of the phosphoric acid solution being 4-6 wt%, and the immersion time being 30-60min.
4. The method as claimed in claim 1, wherein the said fabric is prepared by the process comprising of the steps of: The inert gas is nitrogen, and the flow rate of the nitrogen is 50-200mL / min.
5. The method as claimed in claim 1, wherein the said fabric is prepared by the steps of: The loading process of the phase change materials comprises: Step S41, preparing a phase change material melt; Step S42, preheating the ramie yarns in a reaction kettle to 60-80℃ and vacuumizing to 0.1-0.5kPa; Step S43, injecting the phase change material melt into the reaction kettle and vacuumizing to 0.5-1kPa; Step S44, slowly releasing the vacuum to normal pressure, maintaining 60-80℃ for 60-180min of immersion; Step S45, removing the excess phase change material melt on the surface of the ramie yarns and performing heat treatment on the ramie yarns.
6. A method of preparing a composite ramie fabric as claimed in claim 5, wherein, The phase change material is paraffin or a fatty acid.
7. The method as claimed in claim 5, wherein the said fabric is prepared by using the said yarns in the ratio of 60:
40. 5 The excess phase change material melt is removed by a precision roller or a centrifuge.
8. The method as claimed in claim 1, wherein the said fabric is prepared by the steps of: The loading process of the phase change materials comprises: Step S41', preparing a phase change material solution and heating to 25-70℃; Step S42', immersing the ramie yarns in the phase change material solution and vacuumizing to 0.1-0.5kPa; Step S43', slowly releasing the vacuum to normal pressure, maintaining 25-70℃ for 60-120min of immersion; Step S44', drying at 25-80℃ for 3-5h and performing heat treatment on the ramie yarns.
9. The method for preparing a composite ramie fabric according to claim 8, characterized in that, The phase change material is polyethylene glycol.