Method for manufacturing fibers with phase-change energy storage function

Abstract

The present invention provides a method for manufacturing fibers equipped with a phase-change energy storage function. [Solution] The method includes step 1 of filling a microporous carrier with a phase change material, step 2 of covering the microporous carrier with a polymer having polymer fiber-forming ability, step 3 of preparing a functional masterbatch using the covered microporous carrier, and step 4 of melt spinning the functional masterbatch and the main material of the fiber. [Effects] After a polymer with high-molecular fiber-forming ability is coated with a microporous carrier, the compatibility with the fiber polymer improves, the phase change material is less likely to leak out during granulation and spinning processes, and is easier to store within the fiber. Compared to functional composite fibers with a skin-core structure, the process of this invention is simpler, the fiber yield is higher, and there are no special requirements regarding the type of fiber polymer, resulting in a wide range of applications.

Description

Technical Field

[0001] This application relates to the production of functional fibers, and particularly to a method for producing fibers having a phase change energy storage function.

Background Art

[0002] Chemical fibers are one of the important raw materials for textile products such as clothing. Compared with natural fibers, chemical fibers have the advantages of good stability, wide sources, and long service life. Since the raw materials of chemical fibers have high purity, it is determined that the functions of chemical fibers are single. Usually, multiple fibers are mixed or functional components are added to the fibers to endow the fabric with multiple composite performances. For example, adding nano-particle titanium dioxide to polyamide fibers can produce polyamide raw materials capable of absorbing ultraviolet rays. Adding functional components endows the fibers with better performance. However, due to the material differences between the functional components and the main material of the fibers, the two cannot be well compatible. Moreover, some particulate additive components form stress concentration points, reducing the mechanical properties of the fibers. Furthermore, some additive components should preferably avoid contact with the skin and cannot be exposed to the air, thus limiting their use in functional fibers. Fibers with a skin-core structure are composite fibers, composed of two parts: an outer skin part and an inner core part. The core part may be completely covered by the skin part or partially exposed. The skin part is usually a component of the fiber body, and various functional components can be added to the core part. The surface of the skin-core structure fibers retains the functions of the fiber body, and at the same time, various functional components added to the core part provide additional performance to the fibers. However, there are also problems of interfacial compatibility and strain mismatch due to the material differences between the skin part and the core part in the skin-core structure fibers, which affect the mechanical properties of the fibers. In addition, all conventional devices for manufacturing the skin-core structure adopt the melt spinning method, passing the melt of the skin part and the core part through a hollow annular spinneret at the same time, and cooling the core melt and the skin melt together as they pass through the spinneret to form filaments. This method has high requirements for equipment and technology, and there are also limitations on the melting range of raw materials, and it is impossible to manufacture composite fibers with a large difference in skin and core materials.

[0003] Fibers with phase-change energy storage capabilities are produced by spinning together a phase-change material that can transition between a solid and a liquid state. Currently, the most commonly used type is the skin-core structure fiber described above, where the phase-change material is distributed in the core of the fiber, and the skin portion can enclose the core containing the phase-change material. Skin-core structure composite fibers can avoid exposure of the phase-change functional component. However, the manufacturing technology for skin-core structure fibers is difficult, imposes high restrictions on fiber raw materials, and the core material is easily exposed in the skin portion, affecting the dyeing effect. Therefore, producing fibers with phase-change energy storage capabilities using simple technology, where the phase-change material is not exposed during use and does not come into contact with human skin, is a focus of research for those skilled in the art. [Overview of the project] [Means for solving the problem]

[0004] The manufacturing technology for composite spinning of skin-core structures used in fibers with phase-change energy storage functionality is highly difficult, imposes significant restrictions on the raw materials of the fibers, and the core material is easily exposed to the skin portion, affecting the dyeing effect. To address these challenges, this invention proposes a method for manufacturing fibers with phase-change energy storage functionality, and this method is described below. Step 1 involves filling a microporous support with a phase change material, Step 2 involves covering a microporous support with a polymer having polymer fiber-forming ability, Step 3 involves preparing a functional masterbatch using a covered microporous carrier, The process includes step 4, in which a functional masterbatch and the main fiber material are melt-spun.

[0005] Regarding Step 1, in the fiber equipped with the phase change energy storage function of the present invention, one or more combinations of lauryl alcohol, n-hexadecane, n-heptadecane, octadecane, methyl palmitate, and fatty acid methyl ester are used as the functional phase change material. The phase change temperatures of these substances are approximately 18°C, 24°C, 28°C, 30°C, and 32°C. When the human skin temperature is higher than the phase change temperature, the phase change material changes from solid to liquid. During the process of changing from solid to liquid, the phase change material absorbs heat, lowering the human skin surface temperature and making the person feel cool. When the external temperature changes from a situation where it is higher than the phase change temperature of the phase change material to a situation where it is lower than the temperature of the phase change material, the phase change material changes from liquid to solid. During the process of changing from liquid to solid, the phase change material releases heat, and the human skin does not feel discomfort due to the sudden drop in temperature.

[0006] The microporous support uses oxide particles or microspheres having many pores inside, with a particle size of 0.2 to 50 μm and a pore diameter of 10 to 20 nm. Specifically, it is selected from one of microporous aluminum oxide, microporous silicon dioxide, and microporous titanium dioxide. The molecular particle size of the phase change material in this application is several nanometers to more than ten nanometers, and it can enter the microporous support in a liquid state. The microporous support corresponds to the support for the phase change material.

[0007] To fill the microporous carrier with phase change material as much as possible, it is first necessary to liquefy the phase change material. In a liquid state, the phase change material easily penetrates into the microporous carrier. The microporous carrier and phase change material are then uniformly mixed, heated to 50-70°C, thoroughly stirred, vacuumed, filtered, and the filtered microporous carrier is temporarily stored in an environment lower than the phase change temperature of the phase change material.

[0008] In step 2, the microporous carrier from step 1 is pulverized until its particle size reaches 500 mesh or more, and then an appropriate amount of white oil is added and thoroughly mixed with the microporous carrier. After mixing with a polymer powder having polymer fiber-forming ability in a certain proportion, a microporous carrier covered with a filled phase change material is obtained. The polymer having polymer fiber-forming ability is selected from polyethylene, polyamide, polyethylene terephthalate, and polypropylene. Preferably, in order to improve the spinnability of the fibers, the polymer having polymer fiber-forming ability in step 2 and the masterbatch base material are selected to be the same polymer as the main material of the fibers.

[0009] In step 3, the microporous carrier powder obtained in step 2 is prepared into a functional masterbatch capable of storing phase change energy. Specifically, the microporous carrier powder covered with a fibrous polymer substrate and a filled phase change material is mixed in a fixed ratio. After mixing, the mixture is melted, extruded, cooled, and pelletized to create a functional masterbatch capable of storing phase change energy. By controlling the particle size of the masterbatch and the fibrous polymer to be close, the uneven distribution of certain components due to a large difference in particle size during mixing is avoided. Specifically, the fibrous polymer in this application is selected from polyethylene, polyamide, polyethylene terephthalate, and polypropylene.

[0010] Step 4 involves manufacturing fibers with phase-change energy storage capabilities using a melt spinning method. Specifically, a functional masterbatch capable of storing phase-change energy and the main fiber material are uniformly mixed in a fixed ratio, then melt-extruded through a screw extruder. During processing, the phase-change material is covered in a microporous carrier to minimize the loss of the phase-change material, thereby manufacturing fibers with low loss, low leakage, and uniform dispersion that have phase-change storage capabilities, with the phase-change material covered by the fiber polymer. Specifically, the fiber polymer of this application is selected from polyethylene, polyamide, polyethylene terephthalate, and polypropylene. [Effects of the Invention]

[0011] The beneficial effects of this application are, Firstly, the inventive step of the present invention lies in the spinning method, in which the phase change material is first filled into a microporous material with high thermal conductivity, and then the microporous material is sealed, granulated, and spun. This method effectively reduces the loss of the phase change material during processing and avoids exposure of the phase change material during use. Secondly, in a preferred embodiment, by selecting the same polymer for the polymer having polymer fiber-forming ability, the masterbatch base material, and the main material of the fiber, the microporous material can be dispersed more effectively during the processing process, while the phase change material can also be dispersed more uniformly within the fiber. Third, by using a microporous material with high thermal conductivity as a carrier for the phase change material, the thermal conductivity increases during use, allowing the phase change material to react more quickly and transform into a different form. This allows the human body to adapt to changes in the external environment, resulting in better comfort. Fourth, compared to functional composite fibers with a skin-core structure, the process of this invention is simpler, yields a higher fiber yield, does not have special requirements regarding the type of fiber polymer, and has a wide range of applications. [Brief explanation of the drawing]

[0012] [Figure 1] These are phase change energy storage graphs for the fibers in Examples 1-2 and Comparative Examples 1-3. [Modes for carrying out the invention]

[0013] The present application will be described below based on examples, but the examples given are solely for the purpose of illustrating the present application and are not intended to limit its scope.

[0014] (Example 1) A method for producing polyethylene long fibers with a phase-change energy storage function, comprising the following steps: Step 1: Aluminum oxide microspheres with a particle size of 10 μm and a micropore diameter of 15 nm were uniformly mixed with lauryl alcohol with a phase change temperature of 24°C and octadecane with a phase change temperature of 28°C. The mixture was heated to 50-70°C, thoroughly stirred, then vacuumed and filtered. The filtered microporous aluminum oxide microspheres were then filled with the fatty acid methyl ester and lauryl alcohol phase change materials, and the filtered microporous aluminum oxide microspheres were temporarily stored in an environment lower than the phase change temperature of the phase change materials, i.e., below 18.2°C.

[0015] In step 2, the microporous aluminum oxide microspheres obtained in step 1 are ground until the particle size is 500 mesh or larger. Then, an appropriate amount of white oil is added to thoroughly coat the surface of the aluminum oxide microspheres with the white oil. After that, a certain amount of polyamide powder is thoroughly mixed with the aluminum oxide microspheres so that the polyamide powder thoroughly coats the surface of the aluminum oxide microspheres. At this time, the phase change material is sealed inside the micropores of the aluminum oxide.

[0016] In step 3, the aluminum oxide microspheres from step 2 were mixed with polyethylene powder having fiber-forming ability in a fixed ratio. After mixing, a functional masterbatch capable of storing phase-change energy was obtained by melting, extruding, cooling, and pellet cutting.

[0017] In step 4, the polyethylene chips and the polyethylene phase-change energy-storing functional masterbatch from step 3 were mixed uniformly in a mass ratio of 95:5 and then entered into a spinning machine. The temperatures of sections 1 to 5 of the spinning machine were controlled to 210°C, 215°C, 220°C, 215°C, and 215°C respectively. After melting the polyethylene chips and the polyethylene phase-change energy-storing functional masterbatch, the molten material was extruded through a circular spinning die, and after lateral blow drying, oiling, and drafting, it was packaged to obtain polyethylene fibers with phase-change energy storage capabilities.

[0018] (Example 2) A method for manufacturing polyamide long fibers with a phase change energy storage function, comprising the following steps: Step 1: Uniformly mix microporous silicon dioxide with a D90 particle size of 8 μm and a pore diameter of 10 nm, fatty acid methyl ester with a phase change temperature of 28°C to 32°C, and methyl palmitate with a phase change temperature of 28°C, heat to 50 - 70°C, stir thoroughly, then perform vacuum extraction and filtration. After filtration, the porous silicon dioxide is filled with the fatty acid methyl ester phase change material, and the filtered microporous silicon dioxide is temporarily stored in an environment lower than the phase change temperature of the phase change material, that is, below 32°C.

[0019] Step 2: Grind the microporous silicon dioxide obtained in Step 1 until the particle size reaches 500 mesh or more, add an appropriate amount of white oil, and after sufficiently coating the surface of the microporous silicon dioxide with the white oil, mix thoroughly with a certain amount of polyethylene terephthalate powder so that the polyethylene terephthalate powder sufficiently wraps the surface of the microporous silicon dioxide. At this time, the phase change material is sealed inside the microporous silicon dioxide.

[0020] Step 3: Mix the microporous silicon dioxide in Step 2 with polyethylene terephthalate having fiber-forming ability at a certain ratio. After mixing, melt, extrude, cool, and pelletize to obtain a functional masterbatch capable of storing phase change energy.

[0021] Step 4: Set the mass ratio of polyethylene terephthalate chips to the polyethylene terephthalate phase change energy storage functional masterbatch in Step 3 to 95:5, mix uniformly, then feed it into a spinning machine, control the temperatures of zones 1 to 5 of the spinning machine to 245°C, 255°C, 255°C, 260°C, and 255°C respectively. After melting the polyethylene terephthalate chips and the polyethylene terephthalate phase change energy storage functional masterbatch, the melt is discharged through a circular spinneret, dried by cross blowing, oiled, drafted, and then packaged to obtain polyethylene terephthalate fibers with a phase change energy storage function.

[0022] (Example 3) A method for manufacturing polyethylene terephthalate long fibers with a phase change energy storage function, comprising the following steps: Step 1: Uniformly mix aluminum oxide microspheres with a D90 particle size of 50 μm and a pore diameter of 10 nm, fatty acid methyl esters with a phase change temperature of from 28°C to 32°C, and methyl palmitate with a phase change temperature of 28°C, heat to 50 - 70°C, stir thoroughly, then perform vacuum pumping and filtration. After filtration, the porous aluminum oxide is filled with methyl palmitate and fatty acid methyl ester phase change materials, and the filtered micro-porous aluminum oxide microspheres are temporarily stored in an environment lower than the phase change temperature of the phase change material, that is, lower than 28°C.

[0023] Step 2: Grind the micro-porous aluminum oxide microspheres obtained in Step 1 until the particle size reaches 500 mesh or more, add an appropriate amount of white oil, and after sufficiently coating the surface of the aluminum oxide microspheres with the white oil, mix thoroughly with a certain amount of polyethylene terephthalate powder so as to sufficiently coat the surface of the aluminum oxide microspheres with the polyethylene terephthalate powder. At this time, the phase change material is sealed in the micro-pores of the aluminum oxide.

[0024] Step 3: Mix the aluminum oxide microspheres of Step 2 with polyethylene terephthalate chips having fiber-forming ability at a certain ratio. After mixing, melt, extrude, cool, and pelletize to obtain a functional masterbatch capable of storing phase change energy.

[0025] In step 4, the mass ratio of polyethylene terephthalate chips and the polyethylene terephthalate phase-change energy-storing functional masterbatch from step 3 was set to 95:5, and after uniform mixing, the mixture was placed in a spinning machine. The temperatures of sections 1 to 5 of the spinning machine were controlled to 260°C, 270°C, 280°C, 290°C, and 295°C respectively. After melting the polyethylene terephthalate chips and the polyethylene terephthalate phase-change energy-storing functional masterbatch, the molten material was extruded through a circular spinning die, and after lateral blow drying, oiling, and drafting, it was packaged to obtain polyamide fibers with phase-change energy storage capabilities.

[0026] Examples 1 to 3 described above can also be used to produce short fibers of appropriate specifications using a short fiber spinning method.

[0027] (Comparative Example 1) This is a polyethylene filament produced using a spinning process with polyethylene powder having fiber-forming ability as described in Example 1.

[0028] (Comparative Example 2) This is a polyamide long fiber produced in a spinning process using the polyamide chip having fiber-forming ability as described in Example 2.

[0029] (Comparative Example 3) This is a polyethylene terephthalate filament produced in a spinning process using the polyethylene terephthalate chips of Example 3.

[0030] 1. Contact Cooling Test The phase-change storage fibers of Examples 1-3 and Comparative Examples 1-3 were knitted into 160g single jerseys, and a contact cooling test was conducted. Based on the Japanese standard JIS L1927, measurements were taken using a precision rapid thermophysical property measuring device, and differential scanning calorimetry (DSC) was also used. The test results for the enthalpy of the fibers of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 (Contact Cooling Test Results).

[0031] [Table 1]

[0032] As can be seen from Table 1 above, all of the examples have higher Qmax values ​​compared to the comparative examples, which explains that fabrics knitted using long fibers with phase change energy storage feel cooler the moment they come into contact with the skin. This is because heat from the skin can be instantaneously transferred to the main material of the fiber, then from the main material of the fiber to the microporous material, and the microporous material has a good heat transfer coefficient, and heat can be conducted to the phase change material, and after the phase change material undergoes a phase change, it can absorb more heat, making the human body feel cooler.

[0033] 2. Sustained Cooling Test The phase-change storage fibers of Examples 1-3 and Comparative Examples 1-3 were tested for temperature changes within 60 minutes using 160g of single jersey material, according to the method specified by the Japanese testing institution BOKEN. The test results are shown in Table 2 (Sustained Cooling Test Results).

[0034] [Table 2]

[0035] As can be seen from Table 2, within the 60-minute test period, all the examples had lower temperatures than the comparative examples. This is because the phase-change material absorbs heat through the phase change, keeping the sample surface at a lower temperature and contributing to a sustained cooling effect.

[0036] III. Phase-change energy storage function test The phase-change energy storage fibers of Examples 1-3 and Comparative Examples 1-3 were knitted into 160g single jerseys, and their temperature changes within 45 minutes were tested using the method specified by the Japan Inspection Organization BOKEN. Specifically, after drying, the samples were folded twice, a sensor was placed between the samples, and the constant temperature and humidity chamber was set to 20°C and 60%RH. The samples were placed in the chamber for 2 hours, then the temperature of the chamber was maintained at 40°C and humidity unchanged for 15 minutes, and then the temperature was further changed to 20°C and humidity at 60% for 30 minutes. The temperature changes of each sample within the above 45 minutes were recorded, and the graphs are shown in Figure 1. As can be seen from Figure 1, in the temperature rise phase, the temperature of the example is always lower than that of the comparative example. When the external temperature rises, the phase change material can lower the temperature of the sample surface through phase change endothermic action, thus maintaining coolness. Similarly, in the cooling phase, the temperature of the example is always higher than that of the comparative example. When the external temperature falls, the phase change material can release heat through phase change, replenishing the heat of the sample surface and maintaining warmth. Thus, the fiber equipped with the phase change energy storage function of this application has both phase change endothermic and exothermic functions.

[0037] The foregoing describes only preferred embodiments of the present application and does not limit it; any modifications, equivalent substitutions, improvements, etc., made in the spirit and principles of the present application should be included within the scope of protection.

Claims

1. Step 1 involves filling a microporous carrier with a phase change material, Step 2 involves covering a microporous support with a polymer having polymer fiber-forming ability, Step 3 involves preparing a functional masterbatch using a covered microporous carrier, A method for producing a fiber having a phase change energy storage function, characterized by comprising step 4 of melt spinning a functional masterbatch and the main material of the fiber.

2. The method for producing a fiber having a phase-change energy storage function according to claim 1, characterized in that the phase-change material is a combination of one or more of lauryl alcohol, n-hexadecane, n-heptadecane, octadecane, methyl palmitate, and fatty acid methyl esters.

3. The method for producing a fiber having a phase-change energy storage function according to claim 1, characterized in that the particle size of the microporous carrier is 0.2 to 50 μm, the pore diameter of the micropores is 10 to 20 nm, and one of microporous aluminum oxide, microporous silicon dioxide, and microporous titanium dioxide is selected.

4. The method for producing a fiber having a phase change energy storage function according to claim 1, characterized in that the polymer having polymer fiber-forming ability is selected from polyethylene, polyamide, polyethylene terephthalate, and polypropylene, and the main material of the fiber is selected from polyethylene, polyamide, and polypropylene.

5. The method for producing fibers with a phase change energy storage function according to claim 1, characterized in that step 1 involves uniformly mixing a microporous carrier and an excess of phase change material, heating to 50-70°C, stirring thoroughly, then vacuuming and filtering, and temporarily storing the processed microporous carrier in an environment lower than the phase change temperature of the phase change material.

6. The method for producing a fiber having a phase change energy storage function according to claim 1, characterized in that step 2 involves grinding the microporous carrier from step 1 until the particle size is 500 mesh or more, then adding an appropriate amount of white oil and thoroughly mixing it with the microporous carrier, and finally mixing it with a polymer powder having polymer fiber forming ability in a certain proportion to obtain a microporous carrier covered with a filled phase change material.

7. The method for producing a fiber having a phase change energy storage function according to claim 1, characterized in that step 3 involves uniformly mixing the polymer having polymer fiber-forming ability with the microporous carrier prepared in step 2, and then obtaining a functional masterbatch capable of storing phase change energy by melting, extruding, cooling, and pellet cutting.

8. The method for producing a fiber having a phase change energy storage function according to claim 1, characterized in that step 4 is obtained by melt spinning using the functional masterbatch and main fiber material of step 3 to obtain a short fiber or long fiber having a phase change energy storage function.

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