A cellulose-containing phase change composite fiber material and its preparation method
By introducing cellulose into phase change fiber materials and modifying it with esterification, combined with coaxial wet spinning technology, the problems of insufficient mechanical strength and temperature regulation performance of phase change fiber materials have been solved, achieving a combination of high strength and high efficiency phase change performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG VOCATIONAL & TECHNICAL COLLEGE
- Filing Date
- 2025-06-06
- Publication Date
- 2026-07-31
AI Technical Summary
Existing phase change fiber materials cannot achieve a balance between mechanical strength and temperature regulation performance, and there are problems such as phase change material leakage and interface debonding during thermal cycling, which makes it difficult to meet the application requirements of high-end textiles and apparel.
Cellulose is used as a crosslinking material. By esterifying it with cellulose diacetate, fatty acids or anhydrides and diacids are combined to improve the compatibility between cellulose and phase change materials. Phase change composite fiber materials are then prepared by coaxial wet spinning technology.
The fracture strength and specific heat enthalpy of phase change composite fiber materials were improved, the mechanical properties of the fibers and the encapsulation efficiency of the phase change materials were enhanced, and the deficiencies in thermal stability and phase change performance were solved.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of composite fiber materials technology, and specifically discloses a cellulose-containing phase change composite fiber material and its preparation method. Background Technology
[0002] As a dynamic thermal equilibrium system, the human body transfers heat to the outside world through radiation, conduction, convection, and evaporation when environmental conditions such as temperature, humidity, and airflow speed change. If the body's normal physiological functions cannot maintain this dynamic balance between heat production and dissipation, fluctuations in core body temperature occur, leading to discomfort such as feeling cold or stuffy, and in severe cases, even affecting health and mobility. Therefore, constructing a thermal balance regulation mechanism within the microclimate of clothing has become a key technological direction for improving wearable comfort.
[0003] Phase change temperature regulating materials, with their unique thermophysical properties, can automatically absorb or release latent heat through solid-liquid or liquid-solid phase change processes when the ambient temperature changes, thus achieving active regulation of the microenvironment temperature. This "temperature buffering" function can effectively slow down the rate of heat exchange between the human body and the external environment, creating a relatively stable microclimate environment for the wearer. Therefore, they have shown significant application value in textile and apparel fields with high requirements for thermal comfort, such as outdoor clothing, medical care, and aerospace. After years of technological iteration, new phase change temperature regulating materials have made some progress in terms of phase change enthalpy, thermal stability, and environmental adaptability, but still face many challenges in practical engineering applications.
[0004] As a product of the deep integration of phase change materials and fiber manufacturing technology, phase change fiber's core design concept is to stably embed phase change materials inside the fiber matrix through physical or chemical encapsulation. This special structure allows the phase change material to absorb heat and melt to store heat when the ambient temperature rises, and to release heat by crystallizing when the temperature drops, thereby achieving dynamic buffering of the microenvironment temperature around the fiber. From a materials design perspective, the encapsulation efficiency of the phase change material, the mechanical properties of the fiber matrix, the interfacial compatibility, and the thermal cycling stability during long-term use are the key parameters that determine the actual application effect of phase change fiber. Existing phase change fiber (PCF) preparation technologies suffer from the following limitations: First, while vacuum impregnation based on hollow / porous fiber carriers can achieve initial filling of PCF materials, the process is lengthy (requiring multiple steps such as fiber pretreatment, vacuum impregnation, melt filling, and post-treatment). Furthermore, the resulting PCF fibers are prone to leakage and interface debonding during repeated thermal cycling, leading to a significant decrease in thermal stability. Second, while technologies that directly encapsulate PCF materials during the spinning process (such as melt spinning and electrospinning) have the potential for continuous production, they require extremely high precision in spinning equipment (controlling multiple parameters such as temperature field uniformity and spinning rate), resulting in high equipment investment costs. Moreover, the uniformity of PCF material dispersion and encapsulation efficiency within the fiber are limited by the encapsulation process, making it difficult to meet the demands of large-scale production. In addition, PCF fibers prepared using existing technologies generally suffer from difficulties in balancing mechanical strength and temperature regulation performance, as well as the degradation of phase change efficiency after long-term use, hindering their widespread application in the high-end textile and apparel industry.
[0005] Chinese Patent CN118326560A, an earlier application of this applicant, discloses a phase change composite fiber material and its preparation method. The method involves preparing a core spinning solution using synthetic fibers and a phase change material, and a shell spinning solution composed of polymers, followed by coaxial wet spinning. After the synthetic fibers in the core solidify, they both fix and encapsulate the phase change material, improving its encapsulation rate, and connect with the shell, enhancing the bonding between the core and shell layers of the prepared phase change composite fiber material. Furthermore, this improves the sensitivity of the phase change material in the core to temperature changes, thereby enhancing the temperature regulation performance and shape stability of the prepared phase change composite fiber material. Further observation of this method reveals that it does not examine the tensile strength of the phase change composite fiber material.
[0006] Therefore, the technical problem to be solved in this case is: how to provide a phase change composite fiber material with good mechanical properties and temperature regulation properties. Summary of the Invention
[0007] The purpose of this invention is to provide a cellulose-containing phase change composite fiber material. By using cellulose to bridge the original fibers, the mechanical strength of the original fibers is improved. Furthermore, fatty acids and acid anhydrides or diacids are used to esterify cellulose diacetate to complete the modification. After modification, the compatibility between cellulose and phase change materials can be improved, allowing cellulose to be better mixed with synthetic fibers to better form a cellulose-containing phase change composite fiber material, thereby improving the breaking strength of the product and increasing the specific heat enthalpy of the phase change material.
[0008] Meanwhile, the present invention also discloses a cellulose-containing phase change composite fiber material obtained by the preparation method.
[0009] To achieve this objective, the present invention adopts the following technical solution:
[0010] A method for preparing a cellulose-containing phase change composite fiber material specifically includes the following steps:
[0011] Step 1: Crush and sieve the synthetic fibers, then melt them to obtain synthetic fiber melt.
[0012] Step 2: Mix cellulose diacetate, acetone and phase change material, add fatty acids and acid anhydrides or diacids to cause cellulose diacetate to undergo esterification reaction. After the reaction is completed, remove acetone by vacuum distillation to obtain a mixture.
[0013] Step 3: After mixing the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, perform a first heat treatment to obtain the core spinning solution;
[0014] Step 4: Mix the polymer and organic solvent, and perform a second heat treatment to obtain the shell spinning solution;
[0015] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product obtained by spinning is soaked in water and ethanol in sequence, and then dried to obtain a phase change composite fiber material containing cellulose.
[0016] The composite material obtained through the above steps is nascent fiber. In industrial applications, nascent fiber can be directly rolled or post-treated, such as by heat treatment.
[0017] To obtain better mechanical properties, further heat treatment is required, specifically including the following steps:
[0018] Step 6: Perform dry heat stretching and wet heat stretching on the phase change composite fiber material;
[0019] The temperature for dry heat stretching is 90–110℃;
[0020] The temperature for wet-heat stretching is 170–200℃.
[0021] The fatty acid is a C8 to C18 fatty acid.
[0022] In this invention, the mechanical strength of the original fiber can be improved by using cellulose to crosslink it. The cellulose is partially soluble in organic solvents and has multiple esterification sites, which can provide reaction sites for long-chain group grafting and esterification crosslinking. The modification is completed by using fatty acids and acid anhydrides or diacids to carry out esterification / ester exchange reactions on cellulose diacetate. Cellulose diacetate has a polysaccharide structure, which has a very complex network structure after modification and curing, which can significantly improve the breaking strength of the fiber. Moreover, since it uses phase change material as one of the reaction solvent carriers, it has a very good advantage in improving the specific heat enthalpy of phase change material.
[0023] Modified cellulose is more compatible with phase change materials and can be better mixed with synthetic fibers to form cellulose-containing phase change composite fiber materials, thereby improving the tensile strength of the product and increasing the specific heat enthalpy of the phase change material.
[0024] Preferably, the synthetic fiber described in step 1 is composed of polyester fiber and polyamide fiber in a mass ratio of 1:2 to 3.
[0025] Preferably, the acid anhydride mentioned in step 2 is one or more of maleic anhydride, phthalic anhydride, and butyric anhydride; the dicarboxylic acid is one or more of oxalic acid, isophthalic acid, terephthalic acid, malonic acid, and succinic acid; and the phase change material is one or more of paraffin wax and polyethylene glycol.
[0026] Preferably, the mass ratio of cellulose diacetate, acetone and phase change material in step 2 is 1:10-30:10-30; the mass ratio of cellulose diacetate, fatty acid and acid anhydride or dicarboxylic acid is 1:0.05-0.1:0.05-0.1; and the vacuum distillation temperature is 30-40℃ and the pressure is -0.1MPa.
[0027] Preferably, the mass ratio of the synthetic fiber melt to the mixture in step 3 is 4-8:65.
[0028] Preferably, the mass ratio of the polymer to the organic solvent in step 4 is 1:9-11.5; the polymer is one or more combinations of polyurethane, polyvinylidene fluoride, polyethylene, polystyrene, polypropylene, and polyimide; and the organic solvent is N,N-dimethylformamide.
[0029] Preferably, in the coaxial wet spinning process described in step 5, the ratio of the extrusion speed of the core spinning solution to that of the shell spinning solution is 2:1.
[0030] Preferably, the first heating treatment temperature in step 3 is 200-250℃ and the time is 40-70 min; the second heating treatment temperature in step 4 is 40-80℃ and the time is 30-60 min.
[0031] Meanwhile, the present invention also discloses a cellulose-containing phase change composite fiber material, which is prepared by the preparation method described in any of the preceding claims.
[0032] The beneficial effects of this invention are:
[0033] By using cellulose to bridge the original fibers, the mechanical strength of the original fibers is improved. Furthermore, the esterification reaction of cellulose diacetate with fatty acids, acid anhydrides, or diacids is carried out to complete the modification. After modification, the compatibility between cellulose and phase change materials can be improved, allowing cellulose to be better mixed with synthetic fibers to form cellulose-containing phase change composite fiber materials, thereby improving the breaking strength of the product and increasing the specific heat enthalpy of the phase change material. Detailed Implementation
[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0035] Example 1
[0036] A method for preparing a cellulose-containing phase change composite fiber material, comprising the following steps:
[0037] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:2.5.
[0038] Step 2: Mix 10g cellulose diacetate, 100g acetone, and 100g phase change material (polyethylene glycol with a relative molecular weight of 800), add 0.5g dodecanoic acid and 0.5g maleic anhydride, and react under reflux at 0.1MPa and 80℃ for 2 hours. During the reaction, water separation is performed to remove the water generated during the reaction. After the reaction is completed, acetone is removed by vacuum distillation at 35℃ and -0.1MPa to obtain a mixture.
[0039] Step 3: Mix the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, and then heat it at 240°C for 40 minutes to obtain the core spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65.
[0040] Step 4: Mix polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), and heat at 50°C for 60 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.
[0041] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain a cellulose-containing phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:1.
[0042] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0043] The temperature for dry heat stretching is 100℃;
[0044] The temperature for wet-heat stretching is 180℃.
[0045] Example 2
[0046] The method is largely the same as in Example 1, except that the amounts of dodecanoic acid and maleic anhydride used are 0.8g and 0.2g, respectively.
[0047] Example 3
[0048] The method is largely the same as in Example 1, except that the amounts of dodecanoic acid and maleic anhydride used are 0.2g and 0.8g, respectively.
[0049] Example 4
[0050] The method is largely the same as in Example 1, except that the amounts of dodecanoic acid and maleic anhydride used are 0.8g and 0.8g, respectively.
[0051] Example 5
[0052] The method is largely the same as in Example 1, except that the amounts of dodecanoic acid and maleic anhydride used are 1g and 1g, respectively.
[0053] Example 6
[0054] A method for preparing a cellulose-containing phase change composite fiber material, comprising the following steps:
[0055] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:2.
[0056] Step 2: Mix 10g of cellulose diacetate, 200g of acetone, and 200g of phase change material (polyethylene glycol with a relative molecular weight of 800), add 1g of stearic acid and 1g of succinic acid, and react under reflux at 0.1MPa and 80℃ for 1 hour. During the reaction, water is separated. After the reaction, acetone is removed by vacuum distillation to obtain a mixture. The vacuum distillation temperature is 30℃ and the pressure is -0.1MPa.
[0057] Step 3: Mix the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, and then heat it at 250°C for 40 minutes to obtain the core spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 6:65.
[0058] Step 4: Mix polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), and heat at 40°C for 60 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:9.
[0059] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain a cellulose-containing phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:1.
[0060] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0061] The temperature for dry heat stretching is 100℃;
[0062] The temperature for wet-heat stretching is 180℃.
[0063] Example 7
[0064] A method for preparing a cellulose-containing phase change composite fiber material, comprising the following steps:
[0065] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:3.
[0066] Step 2: Mix 10g of cellulose diacetate, 300g of acetone, and 300g of phase change material (polyethylene glycol with a relative molecular weight of 800), add 0.8g of palmitic acid and 0.8g of succinic acid, and react under reflux at 0.1MPa and 80℃ for 1 hour. During the reaction, water is separated. After the reaction, acetone is removed by vacuum distillation to obtain a mixture. The vacuum distillation temperature is 40℃ and the pressure is -0.1MPa.
[0067] Step 3: Mix the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, and then heat it at 200℃ for 70 minutes to obtain the core spinning solution; wherein the mass ratio of synthetic fiber melt to mixture is 4:65.
[0068] Step 4: After mixing polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), heat-treat at 80℃ for 40 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:11.5.
[0069] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain a cellulose-containing phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:1.
[0070] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0071] The temperature for dry heat stretching is 100℃;
[0072] The temperature for wet-heat stretching is 180℃.
[0073] Comparative Example 1
[0074] A method for preparing a phase change composite fiber material, comprising the following steps:
[0075] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:2.5.
[0076] Step 2: Mix the synthetic fiber melt obtained in Step 1 with the phase change material (polyethylene glycol with a relative molecular weight of 800), and then perform a first heat treatment at 240°C for 40 minutes to obtain the core spinning solution; wherein, the mass ratio of synthetic fiber melt to phase change material is 8:65.
[0077] Step 3: Mix polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), and heat at 50°C for 60 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.
[0078] Step 4: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution and the shell spinning solution is 2:1.
[0079] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0080] The temperature for dry heat stretching is 100℃;
[0081] The temperature for wet-heat stretching is 180℃.
[0082] Comparative Example 2
[0083] A method for preparing a cellulose-containing phase change composite fiber material, comprising the following steps:
[0084] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:2.5.
[0085] Step 2: Mix 10g of cellulose diacetate, 100g of acetone, and 100g of phase change material (polyethylene glycol with a relative molecular weight of 800), add 1g of lauric acid, and react under reflux at 0.1MPa and 80℃ for 2 hours. During the reaction, water separation is performed to remove the water generated during the reaction. After the reaction is completed, acetone is removed by vacuum distillation to obtain a mixture.
[0086] Step 3: Mix the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, and then heat it at 240°C for 40 minutes to obtain the core spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65.
[0087] Step 4: Mix polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), and heat at 50°C for 60 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.
[0088] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain a cellulose-containing phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:1.
[0089] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0090] The temperature for dry heat stretching is 100℃;
[0091] The temperature for wet-heat stretching is 180℃.
[0092] Comparative Example 3
[0093] A method for preparing a cellulose-containing phase change composite fiber material, comprising the following steps:
[0094] Step 1: Crush the synthetic fibers, pass them through a 10-mesh sieve, and then melt them at 240℃ to obtain a synthetic fiber melt; wherein, the synthetic fibers are composed of polyester fibers (relative molecular weight of 16000-25000) and polyamide fibers (relative molecular weight of 10000-20000) in a mass ratio of 1:2.5.
[0095] Step 2: Mix 10g of cellulose diacetate, 100g of acetone, and 100g of phase change material (polyethylene glycol with a relative molecular weight of 800), add 1g of maleic anhydride, and react under reflux at 0.1MPa and 80℃ for 2 hours. During the reaction, water separation is performed to remove the water generated during the reaction. After the reaction is completed, acetone is removed by vacuum distillation to obtain a mixture.
[0096] Step 3: Mix the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, and then heat it at 240°C for 40 minutes to obtain the core spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65.
[0097] Step 4: Mix polyurethane (PU, relative molecular weight <10000) and N,N-dimethylformamide (DMF), and heat at 50°C for 60 min to obtain shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.
[0098] Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product of the coaxial wet spinning is soaked in water at 20°C for 15 minutes, then soaked in ethanol for 10 hours, and dried to obtain a cellulose-containing phase change composite fiber material; wherein, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:1.
[0099] Step 6: The phase change composite fiber material is subjected to dry heat stretching and wet heat stretching to obtain filaments with a diameter of 200 μm;
[0100] The temperature for dry heat stretching is 100℃;
[0101] The temperature for wet-heat stretching is 180℃.
[0102] Performance testing
[0103] The filaments obtained in Examples 1-7 and Comparative Examples 1-3 were tested using the following test methods. The test results are shown in Table 1.
[0104] Tensile strength test: GB / T 14344-2022 Test method for tensile properties of chemical fiber filaments
[0105] Tensile properties test: The test was conducted using an XLB yarn tensile strength tester with a pre-tension of 0.05 cN / dtex, a clamping distance of 250 mm, and a tensile speed of 500 mm / min. The elongation at break was calculated.
[0106] DSC test: The phase change performance of the sample was tested using a differential scanning calorimeter. 10 mg of the phase change composite fiber material to be tested was used as the sample. N2 was used as the protective gas with a flow rate of 30 mL / min. The heating and cooling range was -20 to 120℃, and the heating and cooling rate was 10℃ / min.
[0107] Table 1 Results Data Table
[0108]
[0109] Results analysis:
[0110] 1. The test results of breaking strength and elongation at break show that the strength performance of the product is significantly improved with the addition of diacid / anhydride. This is because cellulose diacetate has a Y-shaped structure, and after modification, the strength of the fiber itself and its compatibility with synthetic fibers can be improved. When this modified fiber is mixed with synthetic fibers for yarn production, the strength of the fiber filaments will increase. At the same time, the modification of cellulose diacetate uses acetone and phase change materials as solvents, and its compatibility with the phase change materials is very good, ultimately improving the compatibility of the composite fiber material, which is reflected in the increase in structural strength.
[0111] 2. Dicarboxylic acids / anhydrides lower the phase transition temperature but increase the enthalpy, indicating that the material structure has undergone a substantial change. It is speculated that the change in the cross-linking density of the fiber itself increases the apparent phase transition enthalpy of the phase change material distributed in the cross-linking network. The presence of the fiber network structure improves the temperature uniformity of the phase change material at each micro-location in the network, thus lowering the phase transition temperature of the phase change material.
[0112] When fatty acids are used as esterification materials, the compatibility between cellulose and phase change materials and fiber materials increases, which raises the phase change temperature of the phase change material to a suitable temperature while maintaining a high phase change enthalpy.
[0113] The above scheme demonstrates that by modifying cellulose diacetate in phase change materials and acetone systems, and then fusing it with synthetic fibers to produce filaments, it is possible to maintain the phase change material at a suitable phase change temperature, increase the phase change enthalpy, and at the same time maintain excellent structural strength.
[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
Claims
1. A method for producing a phase change composite fiber material containing cellulose, characterized by, Specifically, the following steps are included: Step 1: Crush and sieve the synthetic fibers, then melt them to obtain synthetic fiber melt. Step 2: Mix cellulose diacetate, acetone and phase change material, add fatty acids and acid anhydrides or diacids to cause cellulose diacetate to undergo esterification reaction. After the reaction is completed, remove acetone by vacuum distillation to obtain a mixture. Step 3: After mixing the synthetic fiber melt obtained in Step 1 and the mixture obtained in Step 2, perform a first heat treatment to obtain the core spinning solution; Step 4: Mix the polymer and organic solvent, and perform a second heat treatment to obtain the shell spinning solution; Step 5: The core spinning solution obtained in Step 3 and the shell spinning solution obtained in Step 4 are subjected to coaxial wet spinning. The product obtained by spinning is soaked in water and ethanol in sequence, and then dried to obtain a phase change composite fiber material containing cellulose. The fatty acid is a C8~C18 fatty acid; The synthetic fiber described in step 1 is composed of polyester fiber and polyamide fiber in a mass ratio of 1:2~3.
2. The production method according to claim 1, characterized by, The acid anhydride mentioned in step 2 is one or more of maleic anhydride, phthalic anhydride, and butyric anhydride; the dicarboxylic acid is one or more of oxalic acid, isophthalic acid, terephthalic acid, malonic acid, and succinic acid; and the phase change material is one or more of paraffin wax and polyethylene glycol.
3. The preparation method according to claim 1, characterized in that, The mass ratio of cellulose diacetate, acetone, and phase change material in step 2 is 1:10-30:10-30; the mass ratio of cellulose diacetate, fatty acid, and acid anhydride or dicarboxylic acid is 1:0.05-0.1:0.05-0.1; and the vacuum distillation temperature is 30-40℃ and the pressure is -0.1MPa.
4. The method of claim 1, wherein, The mass ratio of the synthetic fiber melt to the mixture in step 3 is 4-8:
65.
5. The preparation method according to claim 1, characterized in that, The mass ratio of the polymer to the organic solvent in step 4 is 1:9-11.5; the polymer is one or more combinations of polyurethane and polyvinylidene fluoride; and the organic solvent is N,N-dimethylformamide.
6. The method of claim 1, wherein, In the coaxial wet spinning process described in step 5, the extrusion speed ratio of the core spinning solution to the shell spinning solution is 2:
1.
7. The preparation method according to claim 1, characterized in that, The first heating treatment in step 3 is performed at a temperature of 200-250℃ for 40-70 minutes; the second heating treatment in step 4 is performed at a temperature of 40-80℃ for 30-60 minutes.
8. The method of claim 1, wherein, Step 5 is followed by step 6: dry heat stretching and wet heat stretching of the phase change composite fiber material; The temperature for dry heat stretching is 90~110℃; The temperature for wet-heat stretching is 170~200℃.
9. A cellulose-containing phase change composite fiber material, characterized by, It is prepared by the preparation method described in any one of claims 1-8.