Phase change temperature regulating lyocell fiber and method of making same

Abstract

The application discloses a phase change temperature regulating Lyocell fiber and a preparation method thereof, and the preparation process is as follows: phase change microcapsules with a certain particle size are dispersed in NMMO aqueous solution to obtain a phase change microcapsule dispersion liquid with a mass ratio of the phase change microcapsules to the NMMO being (0.01-0.1):1, then cellulose is dissolved in the phase change microcapsule dispersion liquid to form a phase change microcapsule / cellulose solution, and after filtration and defoaming, the phase change temperature regulating Lyocell fiber is prepared through dry-jet wet spinning; in the dry-jet wet spinning process, a blowing system with atomizing spraying is adopted to realize sufficient volatilization of the solvent, and by limiting the stretching multiple and the fiber tension in the stretching process, the stability of the fiber in the stretching process is improved, and the filling rate of the microcapsules is ensured; the phase change temperature regulating Lyocell fiber prepared by the above preparation method has excellent heat preservation performance while maintaining the excellent mechanical properties of the Lyocell fiber, and the gram calorie value of the prepared 80g / m<2> fiber fabric is higher than 0.250, and the heat preservation rate is higher than 40.6%. 2 ​

Description

Technical Field

[0001] This invention belongs to the field of fiber technology, specifically relating to a phase change temperature-regulating Lyocell fiber and its preparation method. Background Technology

[0002] With the improvement of people's living standards and the country's increasing advocacy of "green manufacturing," the fiber industry is gradually developing towards intelligence, functionality, and environmental protection. Phase change temperature-regulating fiber is a new type of intelligent textile material that can spontaneously absorb and release heat within a certain range depending on the ambient temperature. It utilizes the heat absorption and release of the phase change material inside the fiber during the phase change process to achieve bidirectional automatic temperature regulation.

[0003] Many countries around the world are conducting special research and development on phase change temperature-regulating fibers and have achieved certain results. However, the preparation technology of phase change fibers in China has been relatively backward, and there are basically no large-scale manufacturers. In today's increasingly fierce international competition, my country's phase change temperature-regulating products are mainly imported. The price of raw materials is controlled by foreign capital, which greatly limits the application of phase change temperature-regulating fibers in China.

[0004] Domestic and international companies have long been engaged in the research and development and manufacturing of phase change temperature-regulating viscose fibers. However, limited by the mechanical properties and production processes of traditional fibers, the produced temperature-regulating fibers cannot meet the processing requirements of apparel textiles and are generally only used as filling materials. Furthermore, due to the limited amount of phase change material added to traditional cellulose solutions, the enthalpy value of traditional temperature-regulating cellulose fibers is difficult to exceed 15 J / g, making it difficult to meet the temperature-regulating capabilities required in high-end applications. Developing temperature-regulating green fibers with high enthalpy value, strong processability, and other comprehensive properties is a major trend in the industry.

[0005] Lyocell fiber, as a new type of cellulose fiber, boasts a green and environmentally friendly production process. Its fiber performance is significantly improved compared to traditional cellulose fibers, and its applications are expanding, gradually becoming a mainstream fiber in our daily lives. Furthermore, the functional development of Lyocell fiber is increasingly being prioritized.

[0006] For example, Chinese invention patent application number CN200880115875.9 discloses a method for preparing Lyocell fibers with temperature regulation capabilities by blending phase change materials with cellulose. However, the enthalpy distribution of the temperature-regulating fibers prepared by this method is uneven, and the fiber loss rate is high during subsequent processing, resulting in increased processing and usage costs.

[0007] Chinese invention patent application number CN200580044121.5 discloses a method for manufacturing a cellulose molded body, particularly Lyocell fiber. Specifically, it discloses a method of sealing a modified substance in microcapsules and mixing the microcapsules into a spinning solution or a spinning solution precursor to obtain modified Lyocell fiber. However, the main technical problem it solves is: improving the compatibility between the modified substance and cellulose by forming microcapsules, thereby successfully modifying the fiber; it does not disclose the influence of process parameters on fiber properties during fiber preparation.

[0008] In view of this, the present invention is proposed. Summary of the Invention

[0009] One of the objectives of this invention is to provide a method for preparing phase change temperature-regulating Lyocell fibers to address the problems in the prior art. By adjusting the process parameters in the fiber preparation and molding process, the enthalpy, clo value, and mechanical properties of the obtained phase change temperature-regulating Lyocell fibers are improved, and large-scale production can be achieved through simple modifications based on existing production equipment.

[0010] Another objective of this invention is to prepare a phase change temperature-regulating Lyocell fiber, which has high enthalpy, high clo value and excellent mechanical properties, and can improve the temperature regulation capability of Lyocell fiber while maintaining the excellent properties of Lyocell fiber to meet the requirements of textile use.

[0011] To achieve the above objectives, the first aspect of the present invention provides a method for preparing phase change temperature-regulating Lyocell fibers, comprising the following steps:

[0012] S1. A phase change microcapsule dispersion is prepared by dispersing phase change microcapsules with a particle size smaller than the fiber diameter in an aqueous solution of NMMO. The amount of phase change microcapsules is 1%-10% of the mass of NMMO.

[0013] S2. Dissolve cellulose in a phase change microcapsule dispersion to prepare a phase change microcapsule / cellulose solution;

[0014] S3. Phase change microcapsules / cellulose solutions are spun using a dry-spray wet spinning method to obtain phase change temperature-regulating Lyocell fibers.

[0015] Furthermore, the phase change microcapsule includes a shell material and a core material encapsulated within the shell material; the shell material is selected from resins or composite materials of several materials, and the core material is selected from organic phase change materials.

[0016] Preferably, the shell material is selected from at least one of epoxy resin, melamine resin, acrylic resin, and silicon dioxide, and the core material is selected from an oleophilic phase change material.

[0017] More preferably, the core material is paraffin wax.

[0018] In the above scheme, the shell material is selected from thermosetting materials that do not react with the NMMO system, such as epoxy resin, melamine resin, acrylic resin, and silica, while the core material is selected from non-polar materials such as paraffin wax. These materials greatly reduce the probability of the microcapsules swelling in the system, which is beneficial to the control of the size of the phase change microcapsules, thereby improving the performance and production stability of the fiber.

[0019] Furthermore, in step S1, the particle size of the phase change microcapsules is less than 2 / 5 of the fiber diameter, the amount of phase change microcapsules used is 2%-8% of the mass of NMMO, and the concentration of NMMO in the phase change microcapsule dispersion ranges from 70% to 85%.

[0020] In the above scheme, limiting the particle size of the phase change microcapsules to less than 2 / 5 of the fiber diameter is the preferred particle size range obtained by technicians based on a large number of experiments and calculations. If the particle size is greater than 2 / 5 of the fiber diameter, the filling rate of the phase change material in the fiber will be greatly reduced, resulting in a significant decrease in its temperature regulation performance. If too many phase change microcapsules are used, the fineness of the fiber will be limited due to the excessive number of microcapsules. If too few microcapsules are used, the enthalpy value of the fiber will decrease.

[0021] Furthermore, in step S1, the phase change microcapsules are uniformly dispersed in an NMMO aqueous solution under the action of a surfactant to form a phase change microcapsule dispersion.

[0022] Preferably, the surfactant is an ionic surfactant.

[0023] The above scheme uses surfactants to effectively prevent the aggregation of phase change microcapsules in NMMO aqueous solution and effectively improves the dispersion uniformity of phase change microcapsules.

[0024] Preferably, the stirring speed is greater than or equal to 500 rpm.

[0025] More preferably, the stirring speed ranges from 1000 to 3500 rpm.

[0026] The stirring speed in the above scheme is a stirring speed that is beneficial to the dispersion of phase change microcapsules, obtained by technicians based on a large number of studies and experiments. If the stirring speed is higher than 3500 rpm, the phase change microcapsules may break or crack due to mutual collisions and collisions with the stirring paddle, which will lead to leakage of phase change material and affect the temperature regulation effect of phase change temperature regulation Lyocell fiber. If the stirring speed is lower than 500 rpm, the phase change microcapsules may not be able to be uniformly dispersed in NMMO aqueous solution, which will affect the uniformity of phase change microcapsules in phase change microcapsule / cellulose solution and lead to a decrease in the temperature regulation performance and mechanical properties of phase change temperature regulation Lyocell fiber.

[0027] Furthermore, in step S2, cellulose with an average degree of polymerization of 250-1100 is used.

[0028] Preferably, the average degree of polymerization of cellulose is 400-800.

[0029] The above-mentioned average degree of polymerization is the optimal range of cellulose polymerization obtained by technicians based on a large number of studies and experiments. Within this range, microcapsules can achieve better dispersion and uniform distribution, which is beneficial to improving the uniformity of the internal structure of the fiber. If the average degree of polymerization is too high, the viscosity of the cellulose solution will increase, and the microcapsules will not be easily dispersed uniformly, resulting in a decrease in the uniformity of the fiber enthalpy value. If the average degree of polymerization is too low, it will affect the mechanical properties of the fiber.

[0030] In step S2, cellulose is dissolved in a phase change microcapsule dispersion under vacuum conditions and a set temperature to obtain a phase change microcapsule / cellulose solution with a viscosity of 700-3500 Pa·s; wherein the set temperature is 80-130℃ and the dissolution time does not exceed 5h.

[0031] The above scheme limits the viscosity of the phase change microcapsule / cellulose solution. If the viscosity is too high, the phase change microcapsules will not be evenly distributed. If the viscosity is too low, it will not be conducive to continuous spinning and will lead to a decrease in spinning stability.

[0032] The optimal dissolution temperature and time for cellulose were determined by technicians based on extensive research and experimentation. Within these temperature and time limits, cellulose can fully dissolve in the phase change microcapsule dispersion to form a solution, ensuring the dimensional stability of the microcapsules and the stability of the solution. Excessive temperature can accelerate the thermal motion of phase change material molecules and solvent molecules, potentially leading to increased particle size due to microcapsule swelling. Furthermore, high temperatures are detrimental to the formation and stability of the cellulose solution, making degradation reactions more likely. Conversely, excessively low temperatures can significantly prolong the dissolution time, which is also detrimental to the dimensional stability of the microcapsules.

[0033] Preferably, the temperature is set at 90-125℃ and the dissolution time does not exceed 3.5 hours.

[0034] Furthermore, in step S2, the cellulose dissolution process also includes stirring, with a stirring time of 1-3.5 hours.

[0035] It should be noted that the stirring residence time refers to the duration of stirring after the cellulose has completely dissolved. The above method ensures the uniform dispersion of the solution through stirring, which in turn helps to improve the uniformity of the fibers in the obtained phase change temperature-controlled Lyocell fibers.

[0036] Furthermore, in step S3, after the phase change microcapsule / cellulose solution is filtered and degassed, it is spun by dry-spray wet spinning to obtain phase change temperature-regulating Lyocell fibers.

[0037] The air section of the dry-jet wet spinning process uses a blowing system with atomized spray.

[0038] In the above scheme, a blowing system with atomizing spray is used to treat the fibers in the air section. The fiber skin can be hooked and solidified faster under the action of water mist, thereby inhibiting the outflow of phase change material caused by the double diffusion process during solidification.

[0039] Furthermore, in step S3, the stretching factor of the phase change temperature-controlled Lyocell fiber during the spinning process is less than or equal to 6 times, and the extrusion molding tension of the phase change temperature-controlled Lyocell fiber is less than or equal to 0.8 CN / dtex.

[0040] In the above scheme, limiting the stretching ratio and fiber tension during the spinning process improves the stability of the phase change temperature-regulating Lyocell fiber during the stretching process, so as to ensure the filling rate of microcapsules. If the stretching ratio is too high, the phase change material will be transferred to the fiber surface during the stretching process, which will easily be lost in subsequent processes. Limiting the tension is to ensure that the fiber reduces wear with the coagulation bath and traction device on the basis of stretching, thereby minimizing the decline in fiber mechanical properties.

[0041] Furthermore, in step S3, the temperature of the coagulation bath is lower than the crystallization temperature of the phase change material; this avoids the loss of the temperature regulation function due to crystallization of the phase change material caused by excessively high temperature; preferably, the temperature range of the coagulation bath is 0-40℃, and the residence time of the phase change microcapsule / cellulose solution in the coagulation bath is not less than 1.5S.

[0042] A second aspect of the present invention provides a phase change temperature-regulating Lyocell fiber prepared by the above-described preparation method.

[0043] Specifically, the obtained phase change temperature-controlled Lyocell fiber has a mechanical strength greater than 2.0 CN / dtex and an enthalpy value higher than 30 J / g. The 80 g / m² fiber obtained using phase change temperature-controlled Lyocell fiber... 2 The clo value of the fiber fabric is higher than 0.250, and the heat retention rate is higher than 40.6%;

[0044] Preferably, the obtained phase change temperature-regulating Lyocell fiber has a mechanical strength greater than 2.4 CN / dtex and an enthalpy value higher than 45 J / g. The 80 g / m² fiber obtained from phase change temperature-regulating Lyocell fiber... 2 The clo value of the fiber fabric is higher than 0.350, and the heat retention rate is higher than 52%.

[0045] Furthermore, after 50 washes, the phase change temperature-regulating Lyocell fiber does not change in fiber strength, and the fiber enthalpy value can still maintain more than 93% of its original value.

[0046] The beneficial effects of adopting this solution are as follows:

[0047] This invention defines the relationship between the particle size of phase change microcapsules and the fiber diameter. The phase change microcapsules are dispersed in an NMMO solution using a surfactant to form a phase change microcapsule dispersion, and the stirring speed during the dispersion process is limited, achieving uniform dispersion of the phase change microcapsules in the NMMO solution. Then, cellulose with a specific degree of polymerization is dissolved in the phase change microcapsule dispersion to form a phase change microcapsule / cellulose solution, resulting in a uniformly dispersed phase change microcapsule / cellulose solution. Furthermore, by adjusting various process parameters in the preparation of phase change temperature-regulating Lyocell fibers, phase change temperature-regulating Lyocell fibers with uniform dispersion of phase change microcapsules and high filling rate are obtained, maintaining high mechanical properties while also giving the phase change temperature-regulating Lyocell fibers excellent temperature regulation capabilities.

[0048] In the preparation of phase change temperature-regulating Lyocell fibers, this invention ensures the uniform dispersion of phase change microcapsules in the system by controlling the degree of polymerization of raw materials and the viscosity of cellulose solution; by controlling the ratio of microcapsule particle size to fiber diameter to ≤2 / 5, the retention rate of phase change materials in the fiber is improved, and the fiber enthalpy and temperature regulation performance are significantly improved.

[0049] This invention improves the stability of Lyocell fibers during the stretching process and ensures their mechanical strength by limiting the stretching ratio and fiber tension during the spinning process. Combined with an air-blowing system with atomized spray, it accelerates fiber surface coagulation, significantly slows down the migration of microcapsules in the cellulose solution during stretching, reduces the content of phase change material on the fiber surface, and minimizes phase change material loss due to double diffusion in the coagulation bath. This ensures the filling rate of phase change material and the washability of the fiber. Through the above control of process parameters in the preparation of Lyocell fibers, Lyocell fibers with uniformly dispersed phase change microcapsules are obtained.

[0050] This invention utilizes ionic surfactants in the industrial production of phase change temperature-regulating Lyocell fibers. The phase change microcapsules and surfactants introduced into the system can be separated by the air flotation filtration device and ion exchange of the solvent recovery system, without affecting the solvent recovery process during production, thus reducing the production cost of phase change fibers to a certain extent. Attached Figure Description

[0051] Figure 1This is a simplified flowchart of the phase change temperature-regulating Lyocell fiber preparation method described in this invention. Detailed Implementation

[0052] The exemplary embodiments of the present invention will be described in more detail below using examples. Those skilled in the art will understand that the following embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0053] In the following examples, a laser particle size analyzer was used to measure the particle size of the phase change microcapsules dispersed in NMMO aqueous solution.

[0054] The viscosity test method is standardized as follows: use a rotational viscometer to test the viscosity at 90℃ and a shear rate of 0.4 (1 / s).

[0055] Example 1

[0056] As an embodiment of the present invention, this embodiment discloses a method for preparing phase change temperature-regulating Lyocell fibers, such as... Figure 1 As shown, the specific process is as follows:

[0057] S1. Phase change microcapsules with a particle size of 5 μm were dispersed in a 70% NMMO solution at a stirring speed of 1500 rpm to obtain a phase change microcapsule dispersion. The dispersion process was treated with sodium dodecylbenzenesulfonate, an ionic surfactant. The particle size of the phase change microcapsule dispersion was tested, and the D90 of the phase change microcapsule dispersion was measured to be 5.33 μm. The mass ratio of phase change microcapsules to NMMO was 0.053:1.

[0058] Specifically, in step S1, the shell material of the phase change microcapsules is made of acrylate resin, and the core material is made of aliphatic hydrocarbons with a crystallization temperature of 16-18℃.

[0059] S2. Cellulose pulp with a degree of polymerization of 420 was added to the phase change microcapsule dispersion prepared in step S1 and dissolved in the phase change microcapsule dispersion under vacuum conditions of 5 kPa at 100°C. The dissolution process was continuously stirred and dissolved for about 1 hour. Then, the mixture was stirred for another 2.5 hours at 105°C to obtain a phase change microcapsule / cellulose solution. The viscosity was measured to be 1300 Pa·s. The particle size distribution of the microcapsules in the cellulose solution was analyzed, and the D90 was 5.72 μm.

[0060] S3. The phase change microcapsule / cellulose solution obtained in step S2 is fed into a filtration device for filtration. The filtration device has a filter size of 15μm. Then, spinning is performed. The fibers ejected from the spinneret first pass through an air section, then through a blowing system with atomizing spray, and finally immerse in a spinning coagulation bath at a temperature of 15℃ for 2.3s. During the spinning process, the fiber tension is controlled at 0.4CN / dtex. Phase change temperature-regulating Lyocell fibers with different fineness are obtained at a stretching ratio of 2.5-5.3 times.

[0061] Example 2

[0062] As an embodiment of the present invention, this embodiment discloses a method for preparing phase change temperature-regulating Lyocell fibers. This embodiment uses phase change microcapsules with a particle size of 3 μm. The shell material of the phase change microcapsules is melamine resin, the core material is aliphatic hydrocarbon, and the crystallization temperature is 28-32℃. Figure 1 As shown, the specific process is as follows:

[0063] S1. Phase change microcapsules were dispersed in a 75% NMMO aqueous solution using a high-speed stirrer at 2000 rpm at a concentration of 4.7% NMMO. The dispersion process was treated with the ionic surfactant sodium dodecylbenzenesulfonate to prepare a phase change microcapsule dispersion. The particle size distribution of the phase change microcapsule dispersion was measured to be 3.42 μm. The mass ratio of phase change microcapsules to NMMO was 0.047:1.

[0064] S2. Cellulose pulp with a degree of polymerization of 800 was added to the phase change microcapsule dispersion prepared in step S1. The mixture was mixed, swollen, and finally dissolved in the phase change microcapsule dispersion under vacuum conditions of 105℃ and 6 kPa for approximately 1.3 hours. Stirring was maintained continuously during the dissolution process, and after the cellulose pulp dissolved, stirring was continued at 100℃ for 2 hours to obtain a phase change microcapsule / cellulose solution. Its viscosity was measured to be 1800 Pa·s. The microcapsule particle size distribution in the cellulose solution was analyzed, and the D90 was 3.68 μm.

[0065] S3. The phase change microcapsule / cellulose solution obtained in step S2 is fed into a filtration device for filtration. The filtration device has a filter size of 20μm. Then, spinning is performed. The fibers ejected from the spinneret first pass through an air section, then through a blowing system with atomizing spray, and finally immerse in a spinning coagulation bath at a temperature of 20℃ for 1.8s. During the spinning process, the fiber tension is controlled at 0.3CN / dtex. Phase change temperature-regulating Lyocell fibers with different fineness are obtained at a stretching ratio of 2.2-4.9.

[0066] Example 3

[0067] As an embodiment of the present invention, this embodiment discloses a method for preparing phase change temperature-regulating Lyocell fibers. This embodiment uses phase change microcapsules with a particle size of 7 μm. The shell material of the phase change microcapsules is selected as silica resin, the core material is selected as aliphatic hydrocarbon, and the crystallization temperature is 21-24℃. Figure 1 As shown, the specific process is as follows:

[0068] S1. Phase change microcapsules were dispersed in a 73% NMMO aqueous solution using a high-speed stirrer at 3500 rpm with 1.7% NMMO by mass. The dispersion process was treated with the ionic surfactant sodium dodecylbenzenesulfonate. The resulting phase change microcapsule / NMMO / aqueous dispersion had a particle size D90 of 7.23 μm. The mass ratio of phase change microcapsules to NMMO was 0.017:1.

[0069] S2. Cellulose pulp with a degree of polymerization of 800 was added to the phase change microcapsule dispersion prepared in step S1 and dissolved in the phase change microcapsule dispersion under vacuum conditions of 5 kPa at 105°C. The dissolution process was continuously stirred and dissolved for about 2 hours. Then, the mixture was stirred for another 2.5 hours at 100°C to obtain a phase change microcapsule / cellulose solution. The viscosity was measured to be 2500 Pa·s. The particle size distribution of the microcapsules in the cellulose solution was analyzed, and the D90 was 8.89 μm.

[0070] S3. The phase change microcapsule / cellulose solution obtained in step S2 is fed into a filtration device for filtration. The filtration device has a filter size of 20 μm. Then, spinning is performed. The fibers ejected from the spinneret first pass through an air section, then through a blowing system with atomizing spray, and finally immerse in a spinning coagulation bath at a temperature of 20°C for 2.6 s. During the spinning process, the fiber tension is controlled at 0.3 CN / dtex. Phase change temperature-regulating Lyocell fibers are obtained at a stretch ratio of 4.2.

[0071] Example 4

[0072] As an embodiment of the present invention, this embodiment discloses a method for preparing phase change temperature-regulating Lyocell fibers. This embodiment uses phase change microcapsules with a particle size of 3 μm. The shell material of the phase change microcapsules is a composite resin, the core material is an aliphatic hydrocarbon, and the crystallization temperature is 22-25℃. Figure 1 As shown, the specific process is as follows:

[0073] S1. Phase change microcapsules were dispersed in a 70% NMMO aqueous solution using a high-speed stirrer at 2500 rpm with 9.2% NMMO by mass. The dispersion process was treated with the ionic surfactant sodium dodecylbenzenesulfonate. The resulting phase change microcapsule / NMMO / aqueous dispersion had a particle size D90 of 2.98 μm. The mass ratio of phase change microcapsules to NMMO was 0.092:1.

[0074] S2. Cellulose pulp with a degree of polymerization of 500 was added to the phase change microcapsule dispersion prepared in step S1 and dissolved in the phase change microcapsule dispersion under vacuum conditions of 5 kPa at 100°C. The dissolution process was continuously stirred and dissolved for about 1.2 hours. Then, the mixture was stirred for another 3 hours at 95°C to obtain a phase change microcapsule / cellulose solution. The viscosity was measured to be 2000 Pa·s. The particle size distribution of the microcapsules in the cellulose solution was analyzed, and the D90 was 3.87 μm.

[0075] S3. The phase change microcapsule / cellulose solution obtained in step S2 is fed into a filtration device for filtration. The filtration device has a filter size of 20 μm. Then, spinning is performed. The fibers ejected from the spinneret first pass through an air section, then through a blowing system with atomizing spray, and finally immerse in a spinning coagulation bath at a temperature of 20°C for 2 seconds. A small amount of microcapsules are precipitated in the coagulation bath. During the spinning process, the fiber tension is controlled at 0.2 CN / dtex. Phase change temperature-regulating Lyocell fibers are obtained at a stretch ratio of 5.2.

[0076] The properties of the phase change temperature-regulating Lyocell fibers prepared in Examples 1 to 4 above were tested, and the test results are shown in the table below:

[0077]

[0078] As can be seen from the test results of the above embodiments, the phase change temperature-regulating Lyocell fiber prepared by the preparation method of the present invention has excellent mechanical properties, with a strength of more than 2.0 CN / dtex, and excellent temperature regulation performance, with an enthalpy value of more than 50 J / g. The temperature regulation performance is good, the enthalpy value does not change much after washing, and the water wash resistance is excellent.

[0079] Example 5

[0080] As an embodiment of the present invention, this embodiment discloses a fabric made using the phase change temperature-regulating Lyocell fiber obtained in Embodiments 1 and 4, named Fabric 1 and Fabric 2 respectively. The thermal conductivity of the fabric obtained in this embodiment and the fabric made of conventional Lyocell fiber were tested according to GB / T 35762-2017 Test Method for Heat Transfer Properties of Textiles (Plane Method). The test results are as follows:

[0081]

[0082]

[0083] It can be seen that the fabric made from the phase change temperature regulating Lyocell fiber prepared by the phase change temperature regulating Lyocell fiber preparation method described in this invention has higher clo value, thermal resistivity and heat retention rate, and excellent temperature regulating performance.

[0084] Comparative Example 1

[0085] In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference from Example 1 lies in the initial particle size of the phase change microcapsules, i.e., the ratio of particle size to fiber diameter is different. Specifically, the properties of the obtained phase change temperature-regulating Lyocell fibers are as follows:

[0086] The following table shows:

[0087]

[0088] The above comparison shows that when the ratio of particle size to fiber diameter is small, the microcapsule filling rate in the fiber is higher and the fiber enthalpy is higher. When the ratio exceeds 0.4, the fiber enthalpy decreases significantly, resulting in poorer fiber temperature regulation ability, but it does not affect washability. The smaller the ratio of particle size to fiber diameter, the better it is for improving fiber temperature regulation performance.

[0089] Comparative Example 2

[0090] In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference from Example 1 lies in the different mass ratio of phase change microcapsules to NMMO in the phase change microcapsule dispersion. The specific mass ratio and the properties of the obtained phase change temperature-regulating Lyocell fibers are shown in the table below:

[0091]

[0092]

[0093] The above comparison shows that when the amount of microcapsules is too low, there is insufficient phase change material inside the fiber after it is formed, which will result in higher mechanical properties and lower enthalpy value of the fiber. The fineness of the fiber determines its load-bearing capacity. When the amount of microcapsules is too high, the fiber will not be able to carry more phase change material. Therefore, it is more appropriate to determine the amount of microcapsules within a reasonable range.

[0094] Comparative Example 3

[0095] In this comparative example, phase change temperature-controlled Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference from Example 1 lies in the use of spinnerets of different specifications to prepare the phase change fibers, resulting in different stretch ratios of the phase change temperature-controlled Lyocell fibers. The specific stretch ratios, tensions, and properties of the obtained phase change temperature-controlled Lyocell fibers are shown in the table below:

[0096]

[0097] The above comparison shows that the fiber stretch ratio affects the distribution of microcapsules within the fiber. A higher stretch ratio allows some microcapsules to migrate from the fiber interior to the fiber surface, making surface microcapsules more susceptible to water washing damage, thus affecting the fiber's wash resistance. Excessive tension increases friction during fiber preparation, leading to poorer mechanical properties. Furthermore, excessive friction causes fibrillation, which is also detrimental to the wash resistance of phase change fibers. Fiber tension can be controlled during fiber preparation by adjusting the air section length and the corresponding guide mechanism to achieve a suitable spinning tension range.

[0098] Comparative Example 4

[0099] In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference between this example and Example 1 lies in the treatment method of the air section during the spinning process. The specific treatment method and the properties of the resulting phase change temperature-regulating Lyocell fibers are shown in the table below:

[0100]

[0101]

[0102] The above comparison shows that the fiber prepared by using atomized spraying in the air section has better wash resistance. The faster coagulation of the skin is more conducive to reducing the phenomenon of microcapsules migrating from the inside to the outside during the stretching process, so that more microcapsules remain inside the fiber and improve water resistance.

[0103] Comparative Example 5: In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method of phase change temperature-regulating Lyocell fibers disclosed in Example 1. The difference between this example and Example 1 lies in the different average degree of polymerization of the cellulose used. The specific average degree of polymerization and the properties of the obtained phase change temperature-regulating Lyocell fibers are shown in the table below:

[0104]

[0105] The above comparison shows that when the degree of polymerization of pulp is low, the microcapsules are well distributed in the cellulose solution, and the fiber enthalpy distribution is more uniform. However, if the degree of polymerization of pulp is too low, below 250, it will seriously affect the spinnability of the fiber, making it difficult to form fibers, and the mechanical properties of the fiber will be very low. If the degree of polymerization of pulp is too high, above 1100, the distribution of microcapsules will be poor, and the uniformity of fiber enthalpy will be poor, which is not conducive to increasing the amount of microcapsules added, thus resulting in a lower enthalpy value.

[0106] Comparative Example 6

[0107] In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference from Example 1 lies in the preparation time of the cellulose solution. The specific dissolution, stirring, and residence times, as well as the properties of the obtained phase change temperature-regulating Lyocell fibers, are shown in the table below:

[0108]

[0109] The above comparison shows that prolonged residence time leads to gradual swelling of microcapsules in NMMO solvent, resulting in increased particle size and decreased filling rate of phase change material in fibers, which is not conducive to improving fiber enthalpy.

[0110] Comparative Example 8

[0111] In this comparative example, phase change temperature-regulating Lyocell fibers were prepared using the preparation method disclosed in Example 1. The difference between this example and Example 1 lies in the viscosity of the cellulose solution. The specific solution viscosity and the properties of the obtained phase change temperature-regulating Lyocell fibers are shown in the table below:

[0112]

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing phase change temperature-regulating Lyocell fibers, characterized in that, Includes the following steps: S1. A phase change microcapsule dispersion is prepared by dispersing phase change microcapsules with a particle size smaller than the fiber diameter in an aqueous solution of NMMO. The amount of phase change microcapsules used is 1%-10% of the mass of NMMO. S2. Dissolve cellulose in a phase change microcapsule dispersion to prepare a phase change microcapsule / cellulose solution; S3. Phase change microcapsules / cellulose solutions are spun using a dry-spray wet spinning method to obtain phase change temperature-regulating Lyocell fibers. In step S1, the particle size of the phase change microcapsules is less than 2 / 5 of the fiber diameter; In step S2, cellulose with an average degree of polymerization of 250-1100 is used; In step S2, under vacuum conditions and a set temperature, cellulose is dissolved in a phase change microcapsule dispersion to obtain a phase change microcapsule / cellulose solution with a viscosity of 700-3500 Pa·s. In step S2, the cellulose dissolution process also includes stirring, with a stirring time of 1-3.5 hours; In step S3, the phase change microcapsule / cellulose solution is filtered and degassed, and then spun by dry-spray wet spinning to obtain phase change temperature-regulating Lyocell fibers. In step S3, the stretching factor of the phase change temperature modulated Lyocell fiber during the spinning process is less than or equal to 6 times, and the extrusion molding tension of the phase change temperature modulated Lyocell fiber is less than or equal to 0.8 CN / dtex.

2. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 1, characterized in that, Phase change microcapsules include a shell material and a core material encapsulated within the shell material; The shell material is selected from resin or a composite material of several materials, and the core material is selected from organic phase change materials.

3. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 1, characterized in that, The shell material is selected from at least one of epoxy resin, melamine resin, acrylic resin, and silicon dioxide, and the core material is selected from oleophilic phase change material.

4. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 1, characterized in that, The core material is paraffin wax.

5. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 1, characterized in that, The amount of phase change microcapsules used is 2%-8% of the mass of NMMO, and the concentration of NMMO in the phase change microcapsule dispersion ranges from 70% to 85%.

6. The method for preparing phase change temperature-regulating Lyocell fibers according to any one of claims 1-5, characterized in that, In step S1, the phase change microcapsules are uniformly dispersed in an NMMO aqueous solution under the action of a surfactant to form a phase change microcapsule dispersion.

7. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 6, characterized in that, The surfactant is an ionic surfactant.

8. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 6, characterized in that, The stirring speed is greater than or equal to 500 rpm.

9. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 6, characterized in that, The stirring speed range is 1000-3500 rpm.

10. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 6, characterized in that, The average degree of polymerization of cellulose is 400-800.

11. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 10, characterized in that, The set temperature is 80-130℃, and the dissolution time is no more than 5 hours.

12. The method for preparing phase change temperature-regulating Lyocell fiber according to claim 11, characterized in that, Set the temperature to 90-125℃ and the dissolution time to no more than 3.5 hours.

13. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 1, characterized in that, The air section of the dry-jet wet spinning process uses a blowing system with atomized spray.

14. The method for preparing phase change temperature-regulating Lyocell fibers according to claim 13, characterized in that, In step S3, the temperature of the coagulation bath is lower than the crystallization temperature of the phase change material.

15. The method for preparing phase change temperature-regulating Lyocell fiber according to claim 14, characterized in that, The temperature range of the coagulation bath is 0-40℃, and the residence time of the phase change microcapsule / cellulose solution in the coagulation bath is not less than 1.5S.

16. A phase change temperature-regulating Lyocell fiber prepared by any one of the preparation methods described in claims 1-15, characterized in that, The mechanical strength of the phase change temperature-regulating Lyocell fiber is greater than 2.0 CN / dtex, and the enthalpy value is higher than 30 J / g. The clo value of the 80 g / m2 fiber fabric made from the phase change temperature-regulating Lyocell fiber is higher than 0.250, and the heat retention rate is higher than 40.6%.

17. The phase change temperature-regulating Lyocell fiber according to claim 16, characterized in that, The mechanical strength of the phase change temperature-regulating Lyocell fiber is greater than 2.4 CN / dtex, the enthalpy value is higher than 45 J / g, and the clo value of the 80 g / m2 fiber fabric made from the phase change temperature-regulating Lyocell fiber is higher than 0.350 and the heat retention rate is higher than 52%.

Images