Phase change composite fiber material containing cellulose and preparation method thereof

Abstract

The invention relates to the technical field of composite fiber materials, and discloses a preparation method of a cellulose-containing phase-change composite fiber material, original fibers are bridged by using cellulose, so that the mechanical strength of the original fibers is improved; the fatty acid and the acid anhydride or the binary acid are utilized to perform esterification reaction on the cellulose diacetate so as to finish modification, and the compatibility of the cellulose and the phase change material can be improved after modification, so that the cellulose can be better mixed with the synthetic fiber, and the cellulose-containing phase change composite fiber material is better formed; further, the breaking strength of the product and the specific enthalpy of the phase-change material are improved. Meanwhile, the invention also discloses the cellulose-containing phase change composite fiber material obtained by the preparation method.

Description

Technical Field

[0001] The invention relates to the technical field of composite fiber materials, and particularly discloses a cellulose-containing phase-change composite fiber material and a preparation method thereof. Background Art

[0002] The human body, as a dynamic thermal equilibrium system, transfers heat to and from the outside world through radiation, conduction, convection, and evaporation when environmental conditions such as temperature, humidity, and airflow velocity change. Once the body's normal physiological functions fail to maintain a dynamic balance between heat production and heat dissipation, core body temperature fluctuates, causing uncomfortable sensations such as cold and stuffiness, and in severe cases, even affecting physical health and mobility. Therefore, establishing a heat balance regulation mechanism within the microclimate zone of clothing has become a key technical direction for improving wearing comfort.

[0003] Phase-change thermoregulatory materials, with their unique thermophysical properties, can automatically absorb or release latent heat through solid-liquid or liquid-solid phase transitions when the ambient temperature changes, achieving active regulation of the microenvironmental temperature. This "temperature buffering" function effectively slows the rate of heat exchange between the human body and the outside world, creating a relatively stable microclimate for the wearer. Consequently, they have demonstrated significant application value in textile and apparel fields with high thermal comfort requirements, such as outdoor clothing, medical care, and aerospace. After years of technological iteration, new phase-change thermoregulatory materials have made considerable progress in terms of phase change enthalpy, thermal stability, and environmental adaptability, but they still face numerous challenges in practical engineering applications.

[0004] Phase change fiber is the product of the deep integration of phase change materials and fiber manufacturing technology. Its core design concept is to stably embed the phase change material inside the fiber matrix through physical or chemical packaging. This special structure enables the phase change material to absorb heat and melt to store heat when the ambient temperature rises, and release heat and crystallize to release heat when the temperature drops, thereby achieving dynamic buffering of the microenvironment temperature around the fiber. From the perspective of material design, the packaging efficiency of the phase change material, the mechanical properties of the fiber matrix, the interface compatibility and the thermal cycle stability during long-term use are the key parameters that determine the actual application effect of phase change fiber. The existing phase change fiber preparation technology has the following main limitations: First, the vacuum impregnation method based on hollow / porous fiber carriers can achieve the initial filling of phase change materials, but the preparation process is lengthy (it requires multiple steps such as fiber pretreatment, vacuum impregnation, melt filling, and post-treatment), and the resulting phase change fibers are prone to phase change material leakage and interface debonding during repeated thermal cycles, resulting in a significant decrease in thermal stability; Second, the technical route of directly encapsulating phase change materials during the spinning process (such as melt spinning, electrospinning, etc.) has the potential for continuous production, but it requires extremely high precision in spinning equipment (it is necessary to control multiple parameters such as temperature field uniformity and spinning rate), the equipment investment cost is high, and due to the limitations of the encapsulation process, the dispersion uniformity and encapsulation efficiency of the phase change material in the fiber need to be improved, making it difficult to meet the needs of large-scale production. In addition, the phase change fibers prepared by existing technologies also generally have problems such as difficulty in balancing mechanical strength and temperature regulation performance, and the attenuation of phase change efficiency after long-term use, which restricts their widespread application in the field of high-end textiles and clothing.

[0005] Chinese patent CN118326560A, a prior application by the present applicant, discloses a phase-change composite fiber material and a method for preparing the same. This method utilizes synthetic fibers and a phase-change material to prepare a core spinning solution and a polymer-based shell spinning solution, which are then coaxially wet-spun. After the synthetic fibers in the core layer solidify, they secure and encapsulate the phase-change material, increasing its encapsulation efficiency. Furthermore, they connect to the shell layer, improving the bonding between the core and shell layers of the prepared phase-change composite fiber material and increasing the sensitivity of the core layer's phase-change material to temperature changes, thereby enhancing the temperature-regulating properties and shape stability of the prepared phase-change composite fiber material. Further observation of this proposal reveals that the breaking strength performance of the phase-change composite fiber material has not been examined.

[0006] Based on this, the technical problem that needs 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 object of the present invention is to provide a cellulose-containing phase-change composite fiber material, which uses cellulose to bridge the original fibers to improve the mechanical strength of the original fibers, and uses fatty acids and acid anhydrides or dibasic acids to esterify diacetyl cellulose and then complete the modification. After the modification, the compatibility of cellulose and phase-change materials can be improved, so that cellulose can be better mixed with synthetic fibers, and a cellulose-containing phase-change composite fiber material can be better formed, thereby improving the breaking strength of the product and increasing the specific heat enthalpy of the phase-change material.

[0008] At the same time, the invention also discloses a cellulose-containing phase-change composite fiber material obtained by the preparation method.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0011] Step 1: crushing and screening the synthetic fibers, and then smelting them to obtain a synthetic fiber melt;

[0012] Step 2: Mixing cellulose diacetate, acetone, and a phase change material, adding fatty acid and acid anhydride or dibasic acid to cause esterification of the cellulose diacetate, and removing the acetone by vacuum distillation after the reaction to obtain a mixture;

[0013] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and performing a first heat treatment to obtain a core layer spinning solution;

[0014] Step 4: mixing the polymer and the organic solvent and performing a second heating treatment to obtain a shell spinning solution;

[0015] Step 5: coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the spinning products in water and ethanol in sequence, and drying to obtain a cellulose-containing phase change composite fiber material;

[0016] The composite material obtained through the above steps is a spun fiber. In industrial applications, the spun fiber can be directly packaged or subjected to post-processing such as heat treatment.

[0017] In order to obtain better mechanical properties, subsequent heat treatment is required, which specifically includes the following steps:

[0018] Step 6: performing dry heat stretching and wet heat stretching on the phase change composite fiber material;

[0019] The temperature of dry heat stretching is 90-110°C;

[0020] The temperature of wet heat stretching is 170 to 200°C.

[0021] The fatty acid is a C8 to C18 fatty acid.

[0022] In the present invention, cellulose is used to bridge the original fibers, thereby improving the mechanical strength of the original fibers. 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 cross-linking. The modification is completed by esterification / ester exchange reaction of diacetyl cellulose using fatty acids and acid anhydrides or dibasic acids. Diacetyl cellulose has a polysaccharide structure, and after modification and curing, it has a very complex network structure, 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 the phase change material.

[0023] The 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 breaking strength of the product and increasing the specific heat enthalpy of the phase change material.

[0024] Preferably, the synthetic fiber 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 described in step 2 is one or more combinations of maleic anhydride, phthalic anhydride, and butyric anhydride; the dibasic acid is one or more combinations of oxalic acid, isophthalic acid, terephthalic acid, malonic acid, and succinic acid; and the phase change material is one or more combinations of paraffin 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 dibasic acid is 1:0.05-0.1:0.05-0.1, and the temperature of the reduced pressure distillation is 30-40°C and the pressure is -0.1 MPa.

[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 extrusion speed ratio of the core layer spinning solution and the shell layer spinning solution is 2:1.

[0030] Preferably, the first heating treatment temperature in step 3 is 200-250° C., and the time is 40-70 min; the second heating treatment temperature in step 4 is 40-80° C., and the time is 30-60 min.

[0031] At the same time, the present invention also discloses a cellulose-containing phase-change composite fiber material, which is prepared by any of the preparation methods described above.

[0032] The beneficial effects of the present invention are:

[0033] By using cellulose to bridge the original fibers, the mechanical strength of the original fibers is improved, and the diacetate cellulose is modified by esterification reaction using fatty acids, acid anhydrides or dibasic acids. After modification, the compatibility of cellulose and phase change materials can be improved, so that cellulose can be better mixed with synthetic fibers and better 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 DESCRIPTION

[0034] Below in conjunction with embodiments of the present invention, technical scheme of the present invention is clearly and completely described, obviously, described embodiment is only a part of embodiment of the present invention, rather than whole embodiment. Based on the embodiment in the present invention, those of ordinary skill in the art, without making the every other embodiment obtained under creative work premise, all fall within the scope of protection of the present invention. It should be noted that, in the embodiment, those not indicating specific conditions, carry out according to the condition of normal condition or manufacturer's suggestion. Reagents used or instrument not indicating manufacturer, all are conventional products that can be obtained by commercial purchase.

[0035] Example 1

[0036] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0037] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:2.5;

[0038] Step 2: 10 g of cellulose diacetate, 100 g of acetone, and 100 g of a phase change material (polyethylene glycol with a relative molecular weight of 800) were mixed, 0.5 g of dodecanoic acid and 0.5 g of maleic anhydride were added, and the mixture was reacted under reflux at 0.1 MPa and 80° C. for 2 h. During the reaction, water was separated to remove the water produced during the reaction. After the reaction, the acetone was removed by vacuum distillation to obtain a mixture. The vacuum distillation temperature was 35° C. and the pressure was -0.1 MPa.

[0039] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and then heating the mixture at 240° C. for 40 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65;

[0040] Step 4: After mixing polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF), heat-treating at 50° C. for 60 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.

[0041] Step 5: Coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a cellulose-containing phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0043] The temperature of dry heat stretching is 100°C;

[0044] The temperature for wet heat stretching was 180°C.

[0045] Example 2

[0046] The process is substantially the same as Example 1, except that the amounts of lauric acid and maleic anhydride used are 0.8 g and 0.2 g, respectively.

[0047] Example 3

[0048] The process is substantially the same as Example 1, except that the amounts of lauric acid and maleic anhydride used are 0.2 g and 0.8 g, respectively.

[0049] Example 4

[0050] The process is substantially the same as Example 1, except that the amounts of lauric acid and maleic anhydride used are 0.8 g and 0.8 g, respectively.

[0051] Example 5

[0052] The process is substantially the same as Example 1, except that the amounts of lauric acid and maleic anhydride used are 1 g and 1 g respectively.

[0053] Example 6

[0054] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0055] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:2;

[0056] Step 2: 10 g of cellulose diacetate, 200 g of acetone, and 200 g of a phase change material (polyethylene glycol with a relative molecular weight of 800) were mixed, 1 g of stearic acid and 1 g of succinic acid were added, and the mixture was reacted under reflux at 0.1 MPa and 80°C for 1 h. During the reaction, water was separated. After the reaction, the acetone was removed by vacuum distillation to obtain a mixture. The vacuum distillation temperature was 30°C and the pressure was -0.1 MPa.

[0057] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and then heating the mixture at 250° C. for 40 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 6:65;

[0058] Step 4: After mixing polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF), heat-treating at 40°C for 60 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:9.

[0059] Step 5: Coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a cellulose-containing phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0061] The temperature of dry heat stretching is 100°C;

[0062] The temperature for wet heat stretching was 180°C.

[0063] Example 7

[0064] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0065] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:3;

[0066] Step 2: 10 g of cellulose diacetate, 300 g of acetone, and 300 g of a phase change material (polyethylene glycol with a relative molecular weight of 800) were mixed, 0.8 g of palmitic acid and 0.8 g of succinic acid were added, and the mixture was reacted under reflux at 0.1 MPa and 80° C. for 1 h. During the reaction, water was separated. After the reaction, the acetone was removed by vacuum distillation to obtain a mixture. The vacuum distillation temperature was 40° C. and the pressure was -0.1 MPa.

[0067] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and heating the mixture at 200° C. for 70 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 4:65;

[0068] Step 4: polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF) were mixed and heated at 80°C for 40 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide was 1:11.5;

[0069] Step 5: Coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a cellulose-containing phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0071] The temperature of dry heat stretching is 100°C;

[0072] The temperature for wet heat stretching was 180°C.

[0073] Comparative Example 1

[0074] A method for preparing a phase change composite fiber material, comprising the following steps:

[0075] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:2.5;

[0076] Step 2: After mixing the synthetic fiber melt obtained in step 1 and the phase change material (polyethylene glycol with a relative molecular weight of 800), a first heat treatment is performed at 240° C. for 40 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the phase change material is 8:65;

[0077] Step 3: polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF) were mixed and heated at 50°C for 60 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide was 1:10;

[0078] Step 4: coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0080] The temperature of dry heat stretching is 100°C;

[0081] The temperature for wet heat stretching was 180°C.

[0082] Comparative Example 2

[0083] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0084] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:2.5;

[0085] Step 2: 10 g of cellulose diacetate, 100 g of acetone, and 100 g of a phase change material (polyethylene glycol with a relative molecular weight of 800) were mixed, 1 g of dodecanoic acid was added, and the mixture was reacted under reflux at 0.1 MPa and 80° C. for 2 h. During the reaction, water was separated to remove the water produced during the reaction. After the reaction, the acetone was removed by vacuum distillation to obtain a mixture.

[0086] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and then heating the mixture at 240° C. for 40 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65;

[0087] Step 4: After mixing polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF), heat-treating at 50° C. for 60 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.

[0088] Step 5: Coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a cellulose-containing phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0090] The temperature of dry heat stretching is 100°C;

[0091] The temperature for wet heat stretching was 180°C.

[0092] Comparative Example 3

[0093] A method for preparing a phase-change composite fiber material containing cellulose, comprising the following steps:

[0094] Step 1: crushing the synthetic fiber, passing it through a 10-mesh sieve, and then melting it at 240° C. to obtain a synthetic fiber melt; wherein the synthetic fiber is composed of polyester fiber (relative molecular weight of 16,000 to 25,000) and polyamide fiber (relative molecular weight of 10,000 to 20,000) in a mass ratio of 1:2.5;

[0095] Step 2: 10 g of cellulose diacetate, 100 g of acetone, and 100 g of a phase change material (polyethylene glycol with a relative molecular weight of 800) were mixed, 1 g of maleic anhydride was added, and the mixture was reacted under reflux at 0.1 MPa and 80° C. for 2 h. During the reaction, water was separated to remove the water generated during the reaction. After the reaction, the acetone was removed by vacuum distillation to obtain a mixture.

[0096] Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and then heating the mixture at 240° C. for 40 minutes to obtain a core layer spinning solution; wherein the mass ratio of the synthetic fiber melt to the mixture is 8:65;

[0097] Step 4: After mixing polyurethane (PU, relative molecular weight <10,000) and N,N-dimethylformamide (DMF), heat-treating at 50° C. for 60 minutes to obtain a shell spinning solution; the mass ratio of polyurethane to N,N-dimethylformamide is 1:10.

[0098] Step 5: Coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the coaxial wet-spun product in 20° C. water for 15 minutes, then soaking it in ethanol for 10 hours, and drying it to obtain a cellulose-containing phase change composite fiber material; wherein the extrusion speed ratio of the core layer spinning solution to the shell layer 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 a filament with a diameter of 200 μm;

[0100] The temperature of dry heat stretching is 100°C;

[0101] The temperature for wet heat stretching was 180°C.

[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] Breaking strength test: GB / T 14344-2022 Test method for tensile properties of chemical fiber filaments

[0105] Tensile performance test: The test was carried out using an XLB yarn strength and elongation 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: Differential scanning calorimetry was used to test the phase change properties of the sample. 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°C, and the heating and cooling rate was 10°C / min.

[0107] Table 1 Result data table

[0108]

[0109] Result analysis:

[0110] 1. The test results of breaking strength and breaking elongation show that with the addition of dibasic acid / anhydride, the product strength performance has been significantly improved. This is because cellulose diacetate has a Y-shaped structure. 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 to make yarn, the strength of the fiber yarn increases. At the same time, the modification of cellulose diacetate uses acetone and phase change material as solvents, and its compatibility with the phase change material itself is very good. Ultimately, the compatibility of the composite fiber material is improved, which is manifested as an increase in structural strength.

[0111] 2. The dibasic acid / anhydride will reduce the phase transition temperature, but increase the thermal enthalpy, indicating that the structure of the material has undergone substantial changes. It is speculated that the change in the cross-linking density of the fiber itself may increase the apparent phase change enthalpy of the phase change material distributed in the cross-linked network. The existence of the fiber network structure improves the temperature uniformity of the phase change material at each microscopic location in the network, thereby reducing the phase transition temperature of the phase change material.

[0112] When fatty acids are additionally used as esterification materials, the compatibility of cellulose with the phase change material and the fiber material increases, which will increase the phase change temperature of the phase change material to a suitable temperature while maintaining a high phase change enthalpy.

[0113] The above scheme shows that by modifying cellulose diacetate in a phase change material and acetone system and then fusing it with synthetic fibers to make silk, the phase change material can be kept at a suitable phase change temperature, the phase change enthalpy can be increased, and excellent structural strength can be maintained.

[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 embodied 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 illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a phase change composite fiber material containing cellulose, characterized in that: The specific steps include: Step 1: crushing and screening the synthetic fibers, and then smelting them to obtain a synthetic fiber melt; Step 2: Mixing cellulose diacetate, acetone, and a phase change material, adding fatty acid and acid anhydride or dibasic acid to cause esterification of the cellulose diacetate, and removing the acetone by vacuum distillation after the reaction to obtain a mixture; Step 3: mixing the synthetic fiber melt obtained in step 1 and the mixture obtained in step 2, and performing a first heat treatment to obtain a core layer spinning solution; Step 4: mixing the polymer and the organic solvent and performing a second heating treatment to obtain a shell spinning solution; Step 5: coaxially wet-spinning the core layer spinning solution obtained in step 3 and the shell layer spinning solution obtained in step 4, soaking the spinning products in water and ethanol in sequence, and drying to obtain a cellulose-containing phase change composite fiber material; The fatty acid is a C8 to C18 fatty acid.

2. The preparation method according to claim 1, characterized in that The synthetic fiber described in step 1 is composed of polyester fiber and polyamide fiber in a mass ratio of 1:2-3.

3. The preparation method according to claim 1, characterized in that The acid anhydride described in step 2 is one or more combinations of maleic anhydride, phthalic anhydride, and butyric anhydride; the dibasic acid is one or more combinations of oxalic acid, isophthalic acid, terephthalic acid, malonic acid, and succinic acid; and the phase change material is one or more combinations of paraffin and polyethylene glycol.

4. The preparation method according to claim 1, characterized in that The mass ratio of the cellulose diacetate, acetone and phase change material in step 2 is 1:10-30:10-30; the mass ratio of the cellulose diacetate, fatty acid and acid anhydride or dibasic acid is 1:0.05-0.1:0.05-0.1, and the temperature of the reduced pressure distillation is 30-40°C and the pressure is -0.1MPa.

5. The preparation method according to claim 1, characterized in that The mass ratio of the synthetic fiber melt to the mixture in step 3 is 4-8:

65.

6. 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, polyvinylidene fluoride, polyethylene, polystyrene, polypropylene, and polyimide; and the organic solvent is N,N-dimethylformamide.

7. The preparation method according to claim 1, characterized in that In the coaxial wet spinning process described in step 5, the extrusion speed ratio of the core layer spinning solution and the shell layer spinning solution is 2:

1.

8. The preparation method according to claim 1, characterized in that The first heating treatment temperature in step 3 is 200-250° C. and the time is 40-70 min; the second heating treatment temperature in step 4 is 40-80° C. and the time is 30-60 min.

9. The preparation method according to claim 1, characterized in that After step 5, the method further includes step 6: performing dry heat stretching and wet heat stretching on the phase change composite fiber material; The temperature of dry heat stretching is 90-110°C; The temperature of wet heat stretching is 170 to 200°C.

10. A phase change composite fiber material containing cellulose, characterized in that: The method is as described in any one of claims 1 to 9.

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